Note: Descriptions are shown in the official language in which they were submitted.
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ELECTRIC PUMP FOR A HYBRID VEHICLE
CROSS-REFERENCE TO RELATED APPLICATION
This application claims the benefit of U.S. Provisional Application No.
61/781,458 filed March 14, 2013, which is hereby incorporated by reference.
BACKGROUND OF THE INVENTION
With the growing concern over global climate change as well as oil supplies,
there has been a recent trend to develop various hybrid systems for motor
vehicles.
While numerous hybrid systems have been proposed, the systems typically
require
significant modifications to the drive trains of the vehicles. These
modifications make
it difficult to retrofit the systems to existing vehicles. Moreover, some of
these
systems have a tendency to cause significant power loss, which in turn hurts
the fuel
economy for the vehicle. Thus, there is a need for improvement in this field.
One of the areas for improvement is in the construction and arrangement of the
hydraulic system. Hybrid vehicles, and in particular the hybrid module
associated with
such a vehicle, have various lubrication and cooling needs which depend on
engine
conditions and operational modes. In order to address these needs, oil is
delivered by
at least one hydraulic pump. The operation of each hydraulic pump is
controlled,
based in part on the lubrication and cooling needs and based in part on the
prioritizing
when one or more hydraulic pump is included as part of the hydraulic system of
the
hybrid vehicle. The prioritizing between hydraulic pumps is based in part on
the needs
and based in part on the operational state or mode of the hybrid vehicle. In
this regard,
an electric (oil) pump can be used in combination with a mechanical (oil)
pump.
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SUMMARY
The hydraulic system (and method) described herein is part of a hybrid module
used within a hybrid system adapted for use in vehicles and suitable for use
in
transportation systems and into other environments. The cooperating hybrid
system is
generally a self-contained and self-sufficient system which is able to
function without
the need to significantly drain resources from other systems in the
corresponding
vehicle or transportation system. The hybrid module includes an electric
machine
(eMachine).
This self-sufficient design in turn reduces the amount of modifications needed
for other systems, such as the transmission and lubrication systems, because
the
capacities of the other systems do not need to be increased in order to
compensate for
the increased workload created by the hybrid system. For instance, the hybrid
system
incorporates its own lubrication and cooling systems that are able to operate
independently of the transmission and the engine. The fluid circulation
system, which
can act as a lubricant, hydraulic fluid, and/or coolant, includes a mechanical
pump for
circulating a fluid, along with an electric pump that supplements workload for
the
mechanical pump when needed. As will be explained in further detail below,
this dual
mechanical/electric pump system helps to reduce the size and weight of the
required
mechanical pump, and if desired, also allows the system to run in a complete
electric
mode in which the electric pump solely circulates the fluid. The focus of this
disclosure is directed at the electric pump.
More specifically, the described hydraulic system (for purposes of the
exemplary embodiment) is used in conjunction with a hybrid electric vehicle
(HEV).
Included as part of the described hydraulic system is a parallel arrangement
of a
mechanical oil pump and an electric oil pump. The control of each pump and the
sequence of operation of each pump depends in part on the operational state or
the
mode of the hybrid vehicle. Various system modes are described herein relating
to the
hybrid vehicle. As for the hydraulic system disclosed herein, there are three
modes
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which are specifically described and these three modes include an electric
mode
(eMode), a transition mode, and a cruise mode.
As will be appreciated from the description which follows, the described
hydraulic system (and method) is constructed and arranged for addressing the
need for
component lubrication and for cooling those portions of the hybrid module
which
experience an elevated temperature during operation of the vehicle. The
specific
construction and operational characteristics provide an improved hydraulic
system for
a hydraulic module.
The compact design of the hybrid module has placed demands and constraints
on a number of its subcomponents, such as its hydraulics and the clutch. To
provide
an axially compact arrangement, the piston for the clutch has a recess in
order to
receive a piston spring that returns the piston to a normally disengaged
position. The
recess for the spring in the piston creates an imbalance in the opposing
surface areas of
the piston. This imbalance is exacerbated by the high centrifugal forces that
cause
pooling of the fluid, which acts as the hydraulic fluid for the piston. As a
result, a
nonlinear relationship for piston pressure is formed that makes accurate
piston control
extremely difficult. To address this issue, the piston has an offset section
so that both
sides of the piston have the same area and diameter. With the areas being the
same,
the operation of the clutch can be tightly and reliably controlled. The
hydraulics for
the clutch also incorporate a spill over feature that reduces the risk of
hydrostatic lock,
while at the same time ensures proper filling and lubrication.
In addition to acting as the hydraulic fluid for the clutch, the hydraulic
fluid
also acts as a coolant for the eMachine as well as other components. The
hybrid
module includes a sleeve that defines a fluid channel that encircles the
eMachine for
cooling purposes. The sleeve has a number of spray channels that spray the
fluid from
the fluid channel onto the windings of the stator, thereby cooling the
windings, which
tend to generally generate the majority of the heat for the eMachine. The
fluid has a
tendency to leak from the hybrid module and around the torque converter. To
prevent
power loss of the torque converter, the area around the torque converter
should be
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relatively dry, that is, free from the fluid. To keep the fluid from escaping
and
invading the torque converter, the hybrid module includes a dam and slinger
arrangement. Specifically, the hybrid module has a impeller blade that propels
the
fluid back into the eMachine through a window or opening in a dam member.
Subsequently, the fluid is then drained into the sump so that it can be
scavenged and
recirculated.
The hybrid module has a number of different operational modes. During the
start mode, the battery supplies power to the eMachine as well as to the
electric pump.
Once the electric pump achieves the desired oil pressure, the clutch piston is
stroked to
apply the clutch. With the clutch engaged, the eMachine applies power to start
the
engine. During the electro-propulsion only mode the clutch is disengaged, and
only
the eMachine is used to power the torque converter. In the propulsion assist
mode, the
engine's clutch is engaged, and the eMachine acts as a motor in which both the
engine
and eMachine drive the torque converter. While in a propulsion-charge mode,
the
clutch is engaged, and the internal combustion engine solely drives the
vehicle. The
eMachine is operated in a generator mode to generate electricity that is
stored in the
energy storage system. The hybrid module can also be used to utilize
regenerative
braking (i.e., regenerative charging). During regenerative braking, the
engine's clutch
is disengaged, and the eMachine operates as a generator to supply electricity
to the
energy storage system. The system is also designed for engine compression
braking, in
which case the engine's clutch is engaged, and the eMachine operates as a
generator as
well.
In addition, the system is also designed to utilize both power takeoff (PTO)
and
electronic PTO (ePTO) modes in order to operate ancillary equipment such as
cranes,
refrigeration systems, hydraulic lifts, and the like. In a normal PTO mode,
the clutch
and the PTO system are engaged, and the internal combustion engine is then
used to
power the ancillary equipment. In an ePTO state, the clutch is disengaged and
the
eMachine acts as a motor to power the ancillary equipment via the PTO. While
in the
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PTO or ePTO operational modes, the transmission can be in neutral or in gear,
depending on the requirements.
Further forms, objects, features, aspects, benefits, advantages, and
embodiments of the present
invention will become apparent from a detailed description and drawings
provided herewith.
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BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 illustrates a diagrammatic view of one example of a hybrid system.
FIG. 2 illustrates a diagrammatic view of one hydraulic system suitable for
use in
the FIG. 1 hybrid system.
FIG. 3 is a perspective view of a hybrid module coupled to a transmission that
is
used in the FIG. 1 hybrid system.
FIG. 4 is a top view of the FIG. 4 hybrid module-transmission subassembly.
FIG. 5 is a perspective, partial cross-sectional view of the hybrid module-
transmission subassembly illustrated in FIG. 3.
FIG. 6 illustrates a diagrammatic view of the FIG. 2 hydraulic system when the
hydraulic system is in an eMode.
FIG. 7 illustrates a diagrammatic view of the FIG. 2 hydraulic system when the
hydraulic system is in a Transition Mode.
FIG. 8 illustrates a diagrammatic view of the FIG. 2 hydraulic system when the
hydraulic system is in a Cruise Mode.
FIG. 9 is a perspective view of an electric pump according to one embodiment
of
the present disclosure.
FIG. 10 is an electrical schematic associated with the FIG. 9 electric pump
according to the present disclosure.
FIG. 11 is an exploded perspective view of an electric pump according to
another embodiment of the present disclosure.
FIG. 12 is a perspective view of the FIG. 11 electric pump as assembled.
FIG. 12A is a partial perspective view of an alternative embodiment with a
three-
bolt mounting pattern.
FIG. 13 is a partial perspective view of the FIG. 12 electric pump, as viewed
from a different direction.
FIG. 14 is a partial perspective view of the FIG. 12 electric pump, in full
section.
FIG. 15 is a partial perspective view of the FIG. 12 electric pump, in full
section.
FIG. 16 is a partial perspective view of the FIG. 12 electric pump, in full
section.
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FIG. 17 is partial perspective view of the FIG. 12 electric pump, showing an 0-
ring location.
FIG. 18 is a partial perspective view of the FIG. 12 electric pump, showing a
new dowel pin location.
FIG. 19 is a partial perspective view of the FIG. 12A electric pump, showing
an
alternate connector orientation.
FIG. 20 is a partial perspective view of the FIG. 12 electric pump, showing a
shortened inlet/outlet conduit length.
FIG. 21 is a partial perspective view of one bolt location of the FIG. 12
electric
pump, showing increased clearance around the bolt head.
FIG. 22 is a diagrammatic illustration of phase 1 of the assembly sequence of
installing the FIG. 12 electric pump into a hybrid module.
FIG. 23 is a diagrammatic illustration of phase 2 of the assembly sequence.
FIG. 24 is a diagrammatic illustration of phase 3 of the assembly sequence.
FIG. 25 is a diagrammatic illustration of phase 4 of the assembly sequence.
FIG. 26 is a perspective view of a dowel pin showing a vent groove.
FIG. 27 is a perspective view of the use of tamper-proof threaded fasteners.
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DETAILED DESCRIPTION
For the purposes of promoting an understanding of the disclosure, reference
will
now be made to the embodiments illustrated in the drawings and specific
language will
be used to describe the same. It will nevertheless be understood that no
limitation of
the scope of the disclosure is thereby intended, such alterations and further
modifications in the illustrated device and its use, and such further
applications of the
principles of the disclosure as illustrated therein being contemplated as
would
normally occur to one skilled in the art to which the disclosure relates.
FIG. 1 shows a diagrammatic view of a hybrid system 100 according to one
embodiment. The hybrid system 100 illustrated in FIG. 1 is adapted for use in
commercial-grade trucks as well as other types of vehicles or transportation
systems,
but it is envisioned that various aspects of the hybrid system 100 can be
incorporated
into other environments. As shown, the hybrid system 100 includes an engine
102, a
hybrid module 104, an automatic transmission 106, and a drive train 108 for
transferring power from the transmission 106 to wheels 110. The hybrid module
104
incorporates an electrical machine, commonly referred to as an eMachine 112,
and a
clutch 114 that operatively connects and disconnects the engine 102 with the
eMachine 112 and the transmission 106.
The hybrid module 104 is designed to operate as a self-sufficient unit, that
is, it
is generally able to operate independently of the engine 102 and transmission
106. In
particular, its hydraulics, cooling and lubrication do not directly rely upon
the engine
102 and the transmission 106. The hybrid module 104 includes a sump 116 that
stores
and supplies fluids, such as oil, lubricants, or other fluids, to the hybrid
module 104 for
hydraulics, lubrication, and cooling purposes. While the terms oil or
lubricant or lube
will be used interchangeably herein, these terms are used in a broader sense
to include
various types of lubricants, such as natural or synthetic oils, as well as
lubricants
having different properties. To circulate the fluid, the hybrid module 104
includes a
mechanical pump 118 and an electric pump 120 in cooperation with a hydraulic
system
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200 (see FIG. 2). With this parallel combination of both the mechanical pump
118 and
electric pump 120, there are opportunities to reduce the overall size and
perhaps the
total cost for the pumps. The electric pump 120 cooperates with the mechanical
pump
118 to provide extra pumping capacity when required. The electric pump 120 is
also
used for hybrid system needs when there is no drive input to operate the
mechanical
pump 118. In addition, it is contemplated that the flow through the electric
pump 120
can be used to detect low fluid conditions for the hybrid module 104.
The hybrid system 100 further includes a cooling system 122 that is used to
cool the fluid supplied to the hybrid module 104 as well as the water-ethylene-
glycol
(WEG) to various other components of the hybrid system 100. In one variation,
the
WEG can also be circulated through an outer jacket of the eMachine 112 in
order to
cool the eMachine 112. Although the hybrid system 100 has been described with
respect to a WEG coolant, other types of antifreezes and cooling fluids, such
as water,
alcohol solutions, etc., can be used. With continued reference to FIG. 1, the
cooling
system 122 includes a fluid radiator 124 that cools the fluid for the hybrid
module 104.
The cooling system 122 further includes a main radiator 126 that is configured
to cool
the antifreeze for various other components in the hybrid system 100. Usually,
the
main radiator 126 is the engine radiator in most vehicles, but the main
radiator 126
does not need to be the engine radiator. A cooling fan 128 flows air through
both fluid
radiator 124 and main radiator 126. A circulating or coolant pump 130
circulates the
antifreeze to the main radiator 126. It should be recognized that other
various
components besides the ones illustrated can be cooled using the cooling system
122.
For instance, the transmission 106 and/or the engine 102 can be cooled as well
via the
cooling system 122.
The eMachine 112 in the hybrid module 104, depending on the operational
mode, at times acts as a generator and at other times as a motor. When acting
as a
motor, the eMachine 112 draws alternating current (AC). When acting as a
generator,
the eMachine 112 creates AC. An inverter 132 converts the AC from the
eMachine 112 and supplies it to an energy storage system 134. In the
illustrated
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example, the energy storage system 134 stores the energy and resupplies it as
direct
current (DC). When the eMachine 112 in the hybrid module 104 acts as a motor,
the
inverter 132 converts the DC power to AC, which in turn is supplied to the
eMachine 112. The energy storage system 134 in the illustrated example
includes
5 three energy storage modules 136 that are daisy-chained together to
supply high
voltage power to the inverter 132. The energy storage modules 136 are, in
essence,
electrochemical batteries for storing the energy generated by the eMachine 112
and
rapidly supplying the energy back to the eMachine 112. The energy storage
modules
136, the inverter 132, and the eMachine 112 are operatively coupled together
through
10 high voltage wiring as is depicted by the line illustrated in FIG. 1.
While the
illustrated example shows the energy storage system 134 including three energy
storage modules 136, it should be recognized that the energy storage system
134 can
include more or less energy storage modules 136 than is shown. Moreover, it is
envisioned that the energy storage system 134 can include any system for
storing
potential energy, such as through chemical means, pneumatic accumulators,
hydraulic
accumulators, springs, thermal storage systems, flywheels, gravitational
devices, and
capacitors, to name just a few examples.
High voltage wiring connects the energy storage system 134 to a high voltage
tap 138. The high voltage tap 138 supplies high voltage to various components
attached to the vehicle. A DC-DC converter system 140, which includes one or
more
DC-DC converter modules 142, converts the high voltage power supplied by the
energy storage system 134 to a lower voltage, which in turn is supplied to
various
systems and accessories 144 that require lower voltages. As illustrated in
FIG. 1, low
voltage wiring connects the DC-DC converter modules 142 to the low voltage
systems
and accessories 144.
The hybrid system 100 incorporates a number of control systems for
controlling the operations of the various components. For example, the engine
102 has
an engine control module (ECM) 146 that controls various operational
characteristics
of the engine 102 such as fuel injection and the like. A transmission/hybrid
control
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module (TCM/HCM) 148 substitutes for a traditional transmission control module
and
is designed to control both the operation of the transmission 106 as well as
the hybrid
module 104. The transmission/hybrid control module 148 and the engine control
module 146 along with the inverter 132, energy storage system 134, and DC-DC
converter system 140 communicate along a communication liffl( as is depicted
in FIG.
1.
To control and monitor the operation of the hybrid system 100, the hybrid
system 100 includes an interface 150. The interface 150 includes a shift
selector 152
for selecting whether the vehicle is in drive, neutral, reverse, etc., and an
instrument
panel 154 that includes various indicators 156 of the operational status of
the hybrid
system 100, such as check transmission, brake pressure, and air pressure
indicators, to
name just a few.
As noted before, the hybrid system 100 is configured to be readily retrofitted
to
existing vehicle designs with minimal impact to the overall design. All of the
systems
including, but not limited to, mechanical, electrical, cooling, controls, and
hydraulic
systems, of the hybrid system 100 have been configured to be a generally self-
contained unit such that the remaining components of the vehicle do not need
significant modifications. The more components that need to be modified, the
more
vehicle design effort and testing is required, which in turn reduces the
chance of
vehicle manufacturers adopting newer hybrid designs over less efficient,
preexisting
vehicle designs. In other words, significant modifications to the layout of a
preexisting
vehicle design for a hybrid retrofit require, then, vehicle and product line
modifications
and expensive testing to ensure the proper operation and safety of the
vehicle, and this
expense tends to lessen or slow the adoption of hybrid systems. As will be
recognized,
the hybrid system 100 not only incorporates a mechanical architecture that
minimally
impacts the mechanical systems of pre-existing vehicle designs, but the hybrid
system
100 also incorporates a control/electrical architecture that minimally impacts
the
control and electrical systems of pre-existing vehicle designs.
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Further details regarding the hybrid system 100 and its various subsystems,
controls, components and modes of operation are described in Provisional
Patent
Application No.
61/381,615, filed September 10, 2010, which is hereby incorporated by
reference in its
entirety.
Referring to FIG. 2, there is illustrated in diagrammatic form a hydraulic
system
200 which is suitably constructed and arranged for use with hybrid system 100.
More
particularly, hydraulic system 200 is a portion of hybrid module 104. Since
the FIG. 2
illustration includes components which interface with a sump module assembly
202,
broken lines 204 are used in FIG. 2 to denote, in diagrammatic form, the
functional
locations of the oil connections from other hydraulic components to the sump
module
assembly 202. Lower case letters are used in conjunction with reference
numeral 204
in order to distinguish the various broken line locations (204a, 204b,etc.).
For
example, the sump 116 is part of the sump module assembly 202, while
mechanical
pump 118 and electric pump 120 are not technically considered to be actual
component
parts of the sump module assembly 202, though this convention is somewhat
arbitrary.
The mechanical pump 118 and the electric pump 120 each have an oil connection
with
the sump module assembly 202. Sump 116 is independent of the sump for the
automatic transmission 106. Broken line 204a diagrammatically illustrates the
location of flow communication between the mechanical pump inlet conduit 206
and
sump 116. Similarly, broken line 204b denotes the location of flow
communication
between the electric pump inlet conduit 208 and sump 116. Inlet conduit 206
defines
inlet conduit opening 206a. Inlet conduit 208 defines inlet conduit opening
208a.
On the flow exiting sides of the two oil pumps, broken line 204c denotes the
location where the outlet 210 of mechanical pump 118 is in flow connection
(and flow
communication with the sump module assembly 202. Broken line 204d denotes the
location where the outlet 212 of the electric pump 120 is in flow connection
(and flow
communication) with the sump module assembly 202. This broken line convention
is
used throughout the FIG. 2 illustration. However, this convention is simply
for
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convenience in explaining the exemplary embodiment and is not intended to be
structurally limiting in any manner. While the other components which have
flow
connections to the sump module assembly 202 are not technically considered
part of
the sump module assembly, these other components, such as the mechanical pump
118
and the electric pump 120, are considered part of the overall hydraulic system
200.
With continued referenced to FIG. 2, hydraulic system 200 includes a main
regulator valve 218, main regulator by-pass valve 220, control main valve 222,
exhaust
back fill valve 224, cooler 226, filter 228, lube splitter valve 230, clutch
trim valve
232, accumulator 234, solenoid 236, and solenoid 238. It will be appreciated
that these
identified component parts and subassemblies of hydraulic system 200 are
connected
with various flow conduits and that pop off valves are strategically
positioned to
safeguard against excessive pressure levels. Further, downstream from the lube
splitter
valve 230 are illustrated elements which are intended to receive oil. The
first priority
of the available oil at the lube splitter valve 230 is for lubrication and
cooling of
bearings 244 and gears or other accessories which are in need of cooling and
lubrication. The second priority, once the first priority has been satisfied,
is to deliver
oil to motor sleeve 246.
The mechanical pump 118 is constructed and arranged to deliver oil to the main
regulator valve 218 via conduit 250. One-way valve 248 is constructed and
arranged
for flow communication with conduit 250 and is positioned downstream from the
mechanical pump 118. Valve 248 is constructed and arranged to prevent
backwards
flow when the engine and (accordingly) the mechanical pump are OFF. Valve 248
includes a ball and spring arrangement set at a threshold of 5 psi. Branch
conduits 252
and 254 provide flow connections to the main regulator valve 218 and the main
regulator by-pass valve 220, respectively. The electric pump 120 is
constructed and
arranged to deliver oil to the main regulator by-pass valve 220 via conduit
256. The
main regulator by-pass valve 220 is in flow communication with main regulator
valve
218 via conduit 258, with control main valve 222 via conduit 260, with clutch
trim
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valve 232 via conduit 262, with cooler 226 via conduit 264 and with solenoid
238 via
conduit 266.
The main regulator valve 218 is in flow communication with conduit 264 via
conduit 272. Conduit 274 is in flow communication with the main regulator
valve 218
and connects to conduit 276 which extends between control main valve 222 and
solenoid 236. Branch conduit 278 establishes a flow path between conduit 274
and
solenoid 238. Conduit 280 establishes flow communication between main
regulator
valve 218 and clutch trim valve 232. Conduit 282 establishes flow
communication
between control main valve 222 and exhaust back fill valve 224. Conduit 284
establishes flow communication between exhaust back fill valve 224 and clutch
trim
valve 232. Conduit 286 establishes flow communication between clutch trim
valve
232 and accumulator 234. Conduit 288 establishes flow communication between
clutch trim valve 232 and conduit 276. Conduit 290 establishes flow
communication
between solenoid 236 and clutch trim valve 232. Conduit 292 establishes a flow
path
(main) between conduit 280 and control main valve 222. Conduit 294 establishes
a
control branch flow connection between conduit 276 and control main valve 222.
Other flow connections and conduits are illustrated in FIG. 2 and the
corresponding
flow path is readily apparent.
Considering the diagrammatic form of FIG. 2, it will be appreciated that the
various flow connections and flow conduits may assume any one of a variety of
forms
and constructions so long as the desired oil flow can be achieved with the
desired flow
rate and the desired flow timing and sequence. The hydraulic system 200
description
makes clear what type of oil flow is required between what components and
subassemblies and the operational reason for each flow path. The hydraulic
system
200 description which corresponds to what is illustrated in FIG. 2 is directed
to what
components and subassemblies are in oil flow communication with each other,
depending on the hybrid system 100 conditions and the operational mode.
Before describing each of the three modes of operation applicable to hydraulic
system 200, the relationship between and some of the construction details
regarding
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the mechanical pump 118 and the electric pump 120 will be described.
Understanding
a few of the pump basics should facilitate a better understanding of the three
modes of
operation selected for further discussion regarding the overall hydraulic
system.
Turning now to some of the mechanical structures, FIG. 3 illustrates a
5 perspective view of the hybrid module 104 attached to the automatic
transmission 106
to form a hybrid module-transmission subassembly 300, and FIG. 4 shows a top
view
of the subassembly 300. As can be seen in FIG. 3, the hybrid module 104
includes a
hybrid module housing 302 that has an engine engagement side 304 where the
hybrid
module 104 engages the engine 102 and a transmission engagement side 306 where
the
10 hybrid module 104 engages the automatic transmission 106. The hybrid
module 104
further includes a high voltage connector box 308 in which high voltage wires
310
from the inverter 132 are received. The three-phase alternating current is
transmitted
via the high voltage wires 310 to the high voltage connector box 308.
The hybrid module 104 is constructed so as to fit between the engine 102 and
15 the automatic transmission 106 without any significant modification to
the overall
vehicular design. In essence, the drive shaft of the vehicle is simply
shortened, and the
hybrid module 104 is inserted between the engine 102 and the automatic
transmission 106, thereby filling the space in between which the longer
driveshaft once
occupied. With that said, the hybrid module 104 is designed specifically to
have a
compact design so as to be easily retrofitted into existing vehicle designs.
Moreover,
the hybrid module 104 as well as the rest of the components are designed to be
easily
assembled and retrofitted to a preexisting automatic transmission 106. As
noted
before, the hybrid module 104 is also designed to be a self-contained/self-
sufficient
unit in which it is able to function without draining resources from other
systems in the
vehicle. For instance, the lubrication and cooling system for the hybrid
module 104
generally operates independent of the engine 102 and the automatic
transmission 106.
As such, it gives the hybrid module 104 greater flexibility in its various
operational
modes. This self-sufficient design in turn reduces the amount of modifications
needed
for other systems, such as the transmission 106, because the capacities of the
other
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systems do not need to be increased in order to compensate for any increased
workload
created by the hybrid module 104. As one example, looking at FIG. 3, the
hybrid
module 104 has the sump 116 that is independent of the sump for the automatic
transmission 106. The electric pump 120 supplements the mechanical pump 118,
which will be described later with respect to FIG. 5, in order to pump fluid
through the
hybrid module 104.
FIG. 5 shows a front, perspective view that includes a partial cross section
through the hybrid module 104 from the perspective of the engine engagement
side 304 of the hybrid module 104. On the engine engagement side 304, the
hybrid
module 104 has the mechanical pump 118 with a pump housing 402 that is secured
to
the hybrid module housing 302. A pump drive gear 404 which is secured to an
input
shaft 406 is used to drive the mechanical pump 118. The drive gear 404 in one
example is secured to the input shaft 406 via a snap ring and key arrangement,
but it is
contemplated that the drive gear 404 can be secured in other manners. The
mechanical
pump 118 in conjunction with the electric pump 120 supplies fluid for
lubrication,
hydraulics, and/or cooling purposes to the hybrid module 104. By incorporating
the
electric pump 120 in conjunction with the mechanical pump 118, the mechanical
pump 118 can be sized smaller, which in turn reduces the required space it
occupies as
well as reduces the cost associated with the mechanical pump 118. Moreover,
the
electric pump 120 facilitates lubrication even when the engine 102 is off.
This in turn
facilitates electric-only operating modes as well as other modes of the hybrid
system 100. Both the mechanical pump 118 and the electric pump 120 recirculate
fluid from the sump 116. The fluid is then supplied to the remainder of the
hybrid
module 104 via holes, ports, openings and other passageways traditionally
found in
transmissions for circulating oil and other fluids. A clutch supply port 408
supplies oil
that hydraulically applies or actuates the clutch 114. In the illustrated
embodiment, the
clutch supply port 408 is in the form of a tube, but is envisioned it can take
other
forms, such as integral passageways within the hybrid module 104, in other
examples.
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As mentioned before, the hybrid module 104 is designed to be easily assembled
to both the engine 102 and the automatic transmission 106. To facilitate a
relatively
easy connection to the engine 102, the input shaft 406 at the engine
engagement
side 304 has a series of splines 410 that are adapted to engage an input drive
disc of the
engine 102. The splines 410 reduce the need for reorienting the crankshaft of
the
engine 102 in order to secure the hybrid module 104 to the engine 102 in the
manner of
a conventional bolt joint flex plate drive system. The input shaft 406 is also
configured to be able to be slid out of the hybrid module 104 for facilitating
servicing
of the input shaft 406 as well as components associated with the input shaft
406. To
further secure the hybrid module 104 to the engine 102, the hybrid module
housing 302 has an engine flange 412 with bolt openings 414 in which bolts 416
are
used to secure the hybrid module 104 to the engine 102.
The operation of the hybrid system 100 involves or includes various
operational modes or status conditions, also referred to herein as "system
modes" or
simply "modes". The principal hybrid system 100 modes are summarized in Table
1
which is provided below:
TABLE I
SYSTEM MODES
Mode Clutch Motor PTO Transmission
Engine Start Engaged Motor Inoperative Neutral
Charge Neutral Engaged Generator Inoperative Neutral
eAssist Propulsion Engaged Motor Inoperative In Gear
eDrive Disengaged Motor Inoperative In Gear
Propulsion with Charge Engaged Generator Inoperative In Gear
Regeneration Charging Disengaged Generator Inoperative In Gear
No Charge Braking Engaged N/A Inoperative In Gear
PTO Engaged N/A Operative Neutral
ePTO Disengaged Motor Operative Neutral
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During an initialization and/or startup mode, the electric pump 120 is
activated
by the transmission/hybrid control module 148 so as to circulate fluid through
the
hybrid module 104. The electric pump 120 receives its power from the energy
storage
system 134 via the inverter 132 (FIG. 1). Once sufficient oil pressure is
achieved, the
clutch 114 is engaged. At the same time or before, the PTO is inoperative or
remains
inoperative, and the transmission 106 is in neutral or remains in neutral.
With the
clutch 114 engaged, the eMachine 112 acts as a motor and in turn cranks the
engine
102 in order to start (i.e., spin/crank) the engine. When acting like a motor,
the
eMachine 112 draws power from the energy storage system 134 via the inverter
132.
Upon the engine 102 starting, the hybrid system 100 shifts to a charge neutral
mode in
which the fuel is on to the engine 102, the clutch 114 is engaged, and the
eMachine 112 switches to a generator mode in which electricity generated by
its
rotation is used to charge the energy storage modules 136. While in the charge
neutral
mode, the transmission remains in neutral.
From the charge neutral mode, the hybrid system 100 can change to a number
of different operational modes. The various PTO operational modes can also be
entered from the charge neutral mode. As should be understood, the hybrid
system is
able to move back and forth between the various operational modes. In the
charge
neutral mode, the transmission is disengaged, that is, the transmission is in
neutral.
Referring to Table 1, the hybrid system 100 enters a propulsion assist or
eAssist
propulsion mode by placing the transmission 106 in gear and having the
eMachine 112
act as a motor.
During the eAssist propulsion mode, a PTO module is inoperative and the fuel
to the engine 102 is on. In the eAssist propulsion mode, both the engine 102
and the
eMachine 112 work in conjunction to power the vehicle. In other words, the
energy to
power the vehicle comes from both the energy storage system 134 as well as the
engine
102. While in the eAssist propulsion mode, the hybrid system 100 can then
transition
back to the charge neutral mode by placing the transmission 106 back into
neutral and
switching the eMachine 112 to a generator mode.
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From the eAssist propulsion mode, the hybrid system 100 can transition to a
number of different operational states. For instance, the hybrid system 100
can
transition from the eAssist propulsion mode to an electrical or eDrive mode in
which
the vehicle is solely driven by the eMachine 112. In the eDrive mode, the
clutch 114 is
disengaged, and the fuel to the engine 102 is turned off so that the engine
102 is
stopped. The transmission 106 is placed in a driving gear. As the eMachine 112
powers the transmission 106, the PTO module is inoperative. While in the
eDrive
mode, the electric pump 120 solely provides the hydraulic pressure for
lubricating the
hybrid module 104 and controlling the clutch 114, because the mechanical pump
118
is not powered by the stopped engine 102. During the eDrive mode, the eMachine
112
acts as a motor. To return to the eAssist propulsion mode, the electric pump
120
remains on to provide the requisite back pressure to engage the clutch 114.
Once the
clutch 114 is engaged, the engine 102 is spun and fuel is turned on to power
the
engine 102. When returning to the eAssist propulsion mode from the eDrive
mode,
both the eMachine 112 and the engine 102 drive the transmission 106, which is
in
gear.
The hybrid system 100 also has a propulsion charge mode, a regenerative
braking charge mode, and a compression or engine-braking mode. The hybrid
system 100 can transition to the propulsion charge mode from the charge
neutral mode,
the eAssist propulsion mode, the regenerative braking charge mode, or the
engine-
braking mode. When in the propulsion charge mode, the engine 102 propels the
vehicle while the eMachine 112 acts as a generator. During the propulsion
charge
mode, the clutch 114 is engaged such that power from the engine 102 drives the
eMachine 112 and the transmission 106, which is in gear. Again, during the
propulsion charge mode, the eMachine 112 acts as a generator, and the inverter
132
converts the alternating current produced by the eMachine 112 to direct
current, which
is then stored in the energy storage system 134. In this mode, the PTO module
is in an
inoperative state. While in the propulsion charge mode, the mechanical pump
118
generally handles most of the oil pressure and lubricant needs, while the
electric pump
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120 provides eMachine cooling. The load between the mechanical 118 and
electric
120 pumps is balanced to minimize power loss.
The hybrid system 100 can transition to a number of operational modes from
the propulsion charge mode. For example, the hybrid system 100 can transition
to the
5 charge neutral mode from the propulsion charge mode by placing the
transmission 106
in neutral. The hybrid system 100 can return to the propulsion charge mode by
placing
the transmission 106 into gear. From the propulsion charge mode, the hybrid
system 100 can also switch to the propulsion assist mode by having the
eMachine 112
act as an electric motor in which electricity is drawn from the energy storage
10 system 134 to the eMachine 112 such that the eMachine 112 along with the
engine 102
drive the transmission 106. The regenerative charge mode can be used to
recapture
some of the energy that is normally lost during braking. The hybrid system 100
can
transition from the propulsion charge mode to the regenerative charge mode by
simply
disengaging the clutch 114. In some instances, it may be desirable to use the
engine-
15 braking mode to further slow down the vehicle and/or to reduce wear of
the brakes.
Transitioning to the engine-braking mode can be accomplished from the
propulsion
charge mode by turning off the fuel to the engine 102. During the engine-
braking
mode, the eMachine 112 acts as a generator. The hybrid system 100 can return
to the
propulsion charge mode by turning back on the fuel to the engine 102. Simply
20 disengaging the clutch 114 will then switch the hybrid system 100 to the
regenerative
charging mode.
The hybrid system 100 is able to conserve energy normally lost during braking
by utilizing the regenerative braking/charge mode. During the regenerative
charge
mode, the clutch 114 is disengaged. The eMachine 112 acts as a generator while
the
transmission 106 is in gear. The power from the wheels of the vehicle is
transferred
through the transmission106 to the eMachine 112, which acts as a generator to
reclaim
some of the braking energy and in turn helps to slow down the vehicle. The
recovered
energy via the inverter 132 is stored in the energy storage system 134. As
noted in
Table 1 above, during this mode the PTO module is inoperative.
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The hybrid system 100 can transition from the regenerative charge mode to any
number of different operational modes. For instance, the hybrid system 100 can
return
to the propulsion assist mode by engaging the clutch 114 and switching the
eMachine 112 to act as a motor. From the regenerative charge mode, the hybrid
system 100 can also return to the propulsion charge mode by engaging the
clutch 114,
and switching the eMachine 112 to the generator role. The hybrid system 100
can also
switch to the engine-braking mode from the regenerative charge mode by turning
off
the fuel to the engine 102 and engaging the clutch.
In addition to the regenerative braking mode, the hybrid system 100 can also
utilize the engine-braking mode in which compression braking of the engine 102
is
used to slow down the vehicle. During the engine braking mode, the
transmission 106
is in gear, the PTO module is inoperative, and the eMachine 112 is acting as a
generator so as to recover some of the braking energy, if so desired. However,
during
other variations of the engine-braking mode, the eMachine 112 does not need to
act as
a generator such that the eMachine 112 draws no power for the energy store
system
module 134. To transmit the energy from the vehicle's wheels, the engine
clutch 114
is engaged and the power is then transmitted to the engine 102 while the fuel
is off In
another alternative, a dual regenerative and engine braking mode can be used
in which
both the engine 102 and the eMachine 112 are used for braking and some of the
braking energy from the eMachine 112 is recovered by the energy storage system
module 134.
The hybrid system 100 can transition from the engine-braking mode to any
number of different operational modes. As an example, the hybrid system 100
can
switch from the engine-braking mode to the propulsion assist mode by turning
on the
fuel to the engine 102 and switching the eMachine 112 to act as an electric
motor.
From the engine-braking mode, the hybrid system 100 can also switch to the
propulsion charge mode by turning back on the fuel to the engine 102. In
addition, the
hybrid system 100 can switch from the engine-braking mode to the regenerative
charge
mode by turning on the fuel to the engine 102 and disengaging the clutch 114.
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When the PTO is used, the vehicle can be stationary or can be moving (e.g.,
for
refrigeration systems). From the charge neutral mode, the hybrid system 100
enters a
PTO mode by engaging the PTO. While in the PTO mode, the clutch 114 is engaged
such that power from the engine 102 is transmitted to the now-operative PTO.
During
this PTO mode, the eMachine 112 acts as a generator drawing supplemental power
from the engine 102 and transferring it via the inverter 132 to the energy
storage
system module 134. At the same time, the transmission 106 is in neutral so
that the
vehicle can remain relatively stationary, if desired. With the PTO operative,
the
ancillary equipment, such as the lift buckets, etc., can be used. The hybrid
system 100
can return to the charge neutral mode by making the PTO inoperative.
During the PTO mode, the engine 102 is constantly running which tends to
waste fuel as well as create unnecessary emissions in some work scenarios.
Fuel can
be conserved and emissions reduced from the hybrid system 100 by switching to
an
electric or ePTO mode of operation. When transitioning to the ePTO mode, the
clutch 114, which transmits power from the engine 102, is disengaged and the
engine 102 is stopped. During the ePTO mode, the eMachine 112 is switched to
act as
an electric motor and the PTO is operative. At the same time, the transmission
106 is
in neutral and the engine 102 is stopped. Having the engine 102 turned off
reduces the
amount of emissions as well as conserves fuel. The hybrid system 100 can
return from
the ePTO mode to the PTO mode by continued operation of the electric pump 120,
engaging the clutch 114 and starting the engine 102 with the eMachine 112
acting as a
starter. Once the engine 102 is started, the eMachine 112 is switched over to
act as a
generator and the PTO is able to operate with power from the engine 102.
With the operation or system modes of hybrid system 100 (see Table 1) in
mind, the hydraulic system 200 is now further described in the context of
three modes
of operation. These three modes include an Electric Mode (eMode), a Transition
Mode, and a Cruise Mode. From the perspective of the status and conditions of
hydraulic system mode the eMode conditions are diagrammatically illustrated in
FIG.
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6. The Transition Mode conditions are diagrammatically illustrated in FIG. 7.
The
Cruise Mode conditions are diagrammatically illustrated in FIG. 8.
Referring first to FIG. 6, in the eMode condition, as represented by hydraulic
system 200a, the engine and clutch are each in an "OFF" condition, and each
solenoid
236 and 238 is an "OFF" condition. The electric pump 120 provides one hundred
percent (100%) of the oil flow to the main regulator valve 218. With solenoid
238 in
an "OFF" condition, there is no solenoid signal to the main regulator by-pass
valve 220
and this component is also considered as being in an "OFF" condition. The main
pressure is "knocked down" to 90 psi due to using only the electric pump 120
and
considering its performance limitations. Any lube/cooling flow to the cooler
226 is the
result of main regulator valve 218 overage.
Referring now to FIG. 7, in the Transition Mode condition as represented by
hydraulic system 200b, the engine may be in either an "ON" or "OFF" condition,
the
clutch is in an "ON" condition, solenoid 238 is "OFF", and solenoid 236 is
"ON". The
electric pump 120 and the mechanical pump 118 can supply a flow of oil to the
main
regular valve 218. The main pressure is knocked down to 90 psi and any
lube/cooling
flow to the cooler 226 is the result of main regulator valve 218 overage.
Referring now to FIG. 8, in the Cruise Mode, as represented by hydraulic
system 200c, the engine and clutch are each in an "ON" condition, and each
solenoid
236 and 238 is an "ON" condition. In this condition, the mechanical pump 118
provides one hundred percent (100%) of the oil flow to the main regulator
valve 218
and to the clutch control hydraulics. The electric pump 120 provides
supplemental
cooler flow (or what may be referred to as cooler flow "boost"). The main
pressure is
at the "normal" (i.e., not knocked down) level of 205 psi. The flow to the
cooler 226 is
by way of the main regulator valve 218 overage and supplemented by flow from
the
electric pump 120.
The three modes which have been described and illustrated in FIGS. 6-8 have
been identified in conjunction with hydraulic systems 200a, 200b, and 200c,
respectively. This numbering scheme of letter suffixes is representative of
the fact that
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the hardware, components, subassemblies, and conduits of hydraulic system 200
do
not change with the different modes of operation. However, the operational
status, the
various ON/OFF conditions, etc. of the hardware, components, and subassemblies
may
change, depending on the particular item and the specific mode of operation.
While the three described modes for the hydraulic system 200 are based in part
on the status or conditions of the engine, these modes are also based in part
on the
ON/OFF status of the referenced hardware, components, and subassemblies,
including
the mechanical pump 118 and the electric pump 120. The mechanical pump 118 is
directly connected to the engine 102 such that when the engine is ON, the
mechanical
pump 118 is ON. When the engine 102 is OFF, the mechanical pump 118 is OFF.
When ON, the mechanical pump 118 delivers oil to the entire hydraulic system.
Any
overage from the main regulator valve 218 is delivered to the cooler 226.
The ON/OFF status of the electric pump 120 and the speed of the electric pump
120 are controlled by the electronics of the hybrid module 104. The electric
pump 120
delivers oil either to the hydraulic system 200 and/or to the cooler 226. When
the
mechanical pump 118 is either OFF or when its delivery of oil is insufficient,
the
electric pump 120 delivers oil to the hydraulic system. When the delivery of
oil from
the mechanical pump is sufficient, the electric pump 120 is able to be used
for delivery
of oil to the cooler for lube and motor cooling.
Reference has been made to the knocked down lower pressure level for certain
operational modes. This knocked down pressure is associated with operation of
the
electric pump 120. Considering the various pressure levels and flow rates, the
main
pressure of the mechanical pump 118 is 205 psi. The main pressure of the
electric
pump 120 is 90 psi. For lube and cooling, the first 5.0 lpm of flow at
approximately
30 psi is used for lube. Any excess flow up to approximately 15.0 lpm is
delivered to
the motor cooling sleeve 246. A maximum of 50 psi for the lube/cooling
function is
attained only after the motor cooling sleeve 240 is filled with oil. The
clutch applied
pressure is 205 psi nominal (1410 kPa) and 188 psi minimum (1300 kPa).
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Referring now to FIG. 9, additional details of one embodiment of a suitable
electric pump 120 are illustrated and described. The pump mechanism 500
includes a
pump inlet 502 and a pump outlet 504. Ignoring for now the precise form of the
mechanical connections between the pump inlet 502 and the sump 116, whether by
5 inlet conduit 208 or by some other similar structure, inlet 502 has a
generally
cylindrical form and surrounds pump outlet 504. Pump outlet 504 is generally
cylindrical and generally concentric with pump inlet 502. The outer surface
502a of
pump inlet 502 defines an annular recessed channel 502b for receipt of 0-ring
506.
Similarly, the outer surface 504a of pump outlet 504 defines an annular
recessed
10 channel 504b for receipt of 0-ring 508.
The electric motor and controller subassembly 514 includes an electrical
connector 516 and an annular mounting flange 518. The mounting flange 518,
illustrated with a bolt circle of externally-threaded mounting studs 520,
could be
alternatively constructed and arranged with a plurality of internally-
threaded, blind
15 holes. The activation or energizing of the electric motor (part of
subassembly 514)
operates the pump mechanism 500 to draw in oil from sump 116 and deliver oil
to the
downstream demands or requirements of the hydraulic system 200, as described
herein.
Referring now to FIG. 10, a circuit schematic for the electric pump 120 and
20 associated with the electric pump 120 is illustrated. The illustrated
electric pump
schematic of FIG. 10 includes electric pump 120 and an integral electric motor
controller 526. As depicted, the electric pump assembly 524, including the
pump 120
and controller 526, is mounted to sandwich housing 528. Controller 526 is
electrically
connected to vehicle battery 530. More specifically, some of the electrical
components
25 within controller 526 are powered by battery 530 via positive and
negative battery
connections 532, 534, respectively. In order to sense the ignition of the
hybrid system,
an ignition switch 536 is disposed on the electrical connection 538 between
the
positive terminal of vehicle battery 530 and controller 526. Vehicle battery
530
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provides various levels of energy depending upon application, such as 12 Volts
or 24
Volts, to name a couple of examples.
In order to power electric pump 120, an energy storage system 540 is
electrically connected to the electric pump assembly 524. In one embodiment,
electric
pump 120 operates at 300 Volts DC at 2 Amps. Depending upon application,
energy
storage system 540 may maintain an energy level greater than 300 Volts. In
those
instances, the voltage level available from energy storage system 540 may be
stepped
down before being provided to the electric pump assembly 524 or within
controller
526 before being provided to pump 120.
Because of the high voltage components located within the electric pump
assembly 524, a high voltage interlock (HVIL) 542 is also provided as a safety
precaution. In the illustrated embodiment, HVIL 542 is electrically and
communicatively connected to electric motor controller 526. Controller 526 is
therefore adapted to trigger HVIL 542 in order to electrically disconnect the
electric
pump assembly 524 from the rest of the vehicle if the high voltage electrical
conditions
become unsafe.
The electric pump assembly 524 is activated and operated by hybrid control
module (HCM) 544. HCM 544 is communicatively connected to electric motor
controller 526 via controller area network (CAN) bus 546. For instance, the
CAN bus
546 can be a 250 k J1939-type data link, a 500 k J1939-type data link, 1000 k
J1939-
type data link, or a PT-CAN type data link, just to name a few examples. All
of these
types of data links can take any number of forms such as metallic wiring,
optical
fibers, radio frequency, and/or a combination thereof, just to name a few
examples. As
appreciated by those of ordinary skill in the art, electrical communication
links, such as
CAN bus 546, can be adversely affected by electromagnetic interference, or
EMI. As
illustrated, CAN bus 546 includes the appropriate CAN shielding in order to
avoid the
negative effects of EMI. Additionally, CAN terminal 548 is provided to
properly
ground CAN bus 546. In another embodiment, HVIL 542 is controlled by HCM 544.
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SAE J1939 is the vehicle bus standard used for communication and diagnostics
among vehicle components, originally by the car and heavy duty truck industry
in the
United States.
J1939 is used in the commercial vehicle area for communication throughout the
vehicle. With a different physical layer it is used between the tractor and
trailer. This
is specified in ISO 11992. SAE J1939 defines five layers in the 7-layer OSI
network
model, and this includes the CAN 2.0b specification (using only the 29-bit/
"extended"
identifier) for the physical and data-link layers. The session and
presentation layers are
not part of the specification. All J1939 packets contain eight bytes of data
and a
standard header which contains an index called PGN (Parameter Group Number),
which is embedded in the message's 29-bit identifier. A PGN identifies a
message's
function and associated data. J1939 attempts to define standard PGNs to
encompass a
wide range of automotive, agricultural, marine and off-road vehicle purposes.
Controller-area network (CAN or CAN-bus) is a vehicle bus standard designed
to allow microcontrollers and devices to communicate with each other within a
vehicle
without a host computer. CAN is a message based protocol, designed
specifically for
automotive applications but now also used in other areas such as industrial
automation
and medical equipment. CAN is one of five protocols used in the OBD-II vehicle
diagnostics standard. The OBD standard is mandatory for all cars and light
trucks sold
in the United States since 1996, and the EOBD standard, mandatory for all
petrol
vehicles sold in the European Union since 2001 and all diesel vehicles since
2004.
Considering the mechanical and electrical details of the disclosed electric
pump
120, the hydraulic system modes of operation, and the overall hybrid module,
several
novel and unobvious aspects relating to electric pump 120 are disclosed.
Referring to FIG. 11, there is illustrated another embodiment of a suitable
electric pump 600 for the type or style of hybrid electric vehicle which is
disclosed
herein. The FIG. 11 illustration is an exploded view of the primary component
parts
with corresponding reference numbers as set forth below in Table II.
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TABLE II
Reference No. Component Part
602 End face seals
604 Dowel pin
606 Dowel pin
608 Spring washer
610 Relief valve spring
612 Valve ball
614 Valve ball
616 0-ring
618 Dowel pin
620 Pump body
622 Motor kit with bus bar
624 Dowel pin
626 Inner rotor
628 0-ring
630 Shaft
632 Cover
634 Outer rotor
636 Sealed connector
638 Screw/Bolt
640 Electrical connector
642 Screw/Bolt
654 Hex head bolt
In the illustrated embodiment of FIG. 11, four hex head bolts 654 are used
(see
also FIGS. 12, 17, 18 and 20). An alternative embodiment (see FIG. 12A), in
terms of
a hex head bolt pattern, uses three hex head bolts. The electric pump of this
three-bolt
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pattern is identified as electric pump 600a. The inlet conduit 644a and outlet
conduit
646a are identified to help orient electric pump 600a. The three bolt
locations are
denoted by the three flange holes 609. The decision or choice on the bolt
pattern
depends on other housing, casting and packaging considerations. Although the
four-
bolt pattern is shown in other drawings, the three-bolt pattern is considered
preferable
based on the current housing/casting construction and arrangement.
FIG. 12 provides a perspective view of the electric pump 600 assembly, as
viewed from the opposite end of the exploded view provided by FIG. 11. FIG. 13
is a
partial perspective view from still another angle or direction. FIGS. 14-16
provide
partial section views of the interior of electric pump 600. Included are the
inner and
outer rotors 626 and 634, respectively, which comprise the gerotor 627. With
continued reference to FIG. 14, the referenced "gerotor" 627 which is
incorporated into
electric pump 600 (including electric pump 600a) is positioned so as to be
generally
concentric with the motor 629. Typically, a gerotor and motor are arranged end
to end
in an axial stack or sequential series. By changing the respective locations
such that
the gerotor 627 and motor 629 are concentric (and coaxial) there is
significant space
conservation producing a more compact package. The inner rotor 626 is also
referred
to as the inner gear 626 of the gerotor 627 (see FIG. 11). The outer rotor 634
is also
referred to as the outer gear 634 of the gerotor 627 (see FIG. 11).
The motor 629 includes a stator 631, a two-piece shaft 630 and a stainless
steel
liner 633 concentrically positioned between the stator 631 and the permanent
magnet
liner 635 which separates the stainless steel liner 633 from the outer gear
634 (see
FIGS. 14 and 15). The permanent magnet liner 635 includes a plurality of
permanent
magnets which are either bonded to and/or embedded in a stainless steel layer.
This
combination of integrated component parts is illustrated as a unitary
structure and
singularly defined as liner 635. Broken line 630a denotes the line of
separation
between the two sections or portions which comprise shaft 630.
One of the design features of electric pump 600 is the longer 0-ring landing
as
illustrated in FIG. 17. Another design feature is the separated dowel pin as
illustrated
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in FIG. 18. Another design feature is the arrangement and orientation of
connector 640
as illustrated in FIG. 19. Another design feature is a shorter inlet/outlet
assembly, as
illustrated in FIG. 20. Another design feature is adding clearance around each
bolt
head such that a standard socket wrench can be applied to the bolt head
without
5 interference. A representative example of this clearance is illustrated
in FIG. 21.
With continued reference to FIG. 21, the generally cylindrical area or zone
surrounding the head 654a of bolt 654, as denoted by broken line 655,
represents bolt
head clearance for a standard socket wrench of an 18mm diameter. The
approximate
diameter size of this clearance area or zone is 19.6mm, a dimension which
generally
10 corresponds to the referenced socket wrench.
The assembly sequence for electric pump 600, as it is installed into the
hybrid
module, is illustrated in FIGS. 22-25. The first step or phase (see FIG. 22)
is to align
the pump body with the opening in the hybrid module which is constructed and
arranged to receive the face-seal end of electric pump 600. Several points of
contact or
15 engagement must be monitored, including the 0-ring 616 and the dowel pin
606.
The next phase or step in the assembly sequence, see FIG. 23, is to establish
dowel pin engagement between dowel pin 606 and the machine bore in the hybrid
module. At this phase in the assembly sequence, the 0-ring 616 has not yet
been
contacted for compression and the face seals 602 are not yet in abutment
against the
20 interior surface of the hybrid module.
As the dowel pin 606 continues into the machined bore 660 of the hybrid
module, contact and compression of 0-ring 616 begins as the enclosing surface
of the
hybrid module begins to push against the outwardly protruding portion of the 0-
ring
616, see FIG. 24. Abutment of face seal 602 has not yet occurred at this phase
of the
25 assembly sequence. The final phase, see FIG. 25, has the dowel pin 606
fully inserted
into the receiving bore 660 and the face seal 602 pushed into abutment (i.e.,
engagement) against the inner surface of the hybrid module.
With continued reference to FIGS. 11, 12, and 13, the assembled electric pump
600 includes an electrical connector 640 at one end and the inlet and outlet
conduits
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644 and 646, respectively, at the opposite end. Inserted and secured into the
end of
each conduit 644 and 646 is a face seal 602. Internally, the outlet conduit
646 includes
a one-way valve 648 (see FIG. 16) and a pressure regulating and reducing valve
(PRV)
650. The one-way valve 648 includes valve ball 614 and dowel pin 618. The PRV
650 includes valve ball 612, valve spring 610, and dowel pin 604 (see FIG.
16). The
PRV 650 is used to manage the hydraulic fluid pressure within the pump and
thus
within the exiting flow path via outlet conduit 646. Valve 648 allows the
hydraulic
fluid to exit based on the flow rate and pressure created by the gerotor
pumping
mechanism. Essentially no resistance is offered by ball 614 which only acts to
prevent
reverse flow. If the hydraulic fluid pressure within pump 600 (or pump 600a)
and seen
within conduit 646 is too high, ball 612 pushes up against spring 610 and a by-
pass
passage is opened for hydraulic fluid to leave the electric pump and return to
sump.
The use of PRV 650 protects the interior of pump 600 from excessive internal
pressures. An elevated pressure might be due to a blockage or other
restriction. Once
the elevated pressure is relieved, the PRV 650 closes. The threshold pressure
to open
PRV 650 is managed by the size of ball 612 and by the selected spring constant
for
spring 610. In the exemplary embodiment PRV 650 has its threshold pressure set
at
900Kpa 70Kpa.
Another design feature which is incorporated into the construction of electric
pump 600 (as well as electric pump 600a) pertains to the construction of one
or more
of the dowel pins 606 and 624. Referring to FIG. 26, a generic dowel pin 619
is
illustrated as being representative of dowel pins 606 and/or dowel pins 624.
Dowel
pin 619 includes a swirl cut pattern which is denoted by spiral groove 619a.
This
dowel pin groove 619a is constructed and arranged to prevent "pressure lock".
When a
smooth and close line-to-line fitting dowel pin is inserted into a bore, the
trapped air
can create an abutment to the continued advancement of the dowel pin. This air
pressure lock can be eliminated by allowing the otherwise trapped air to
escape via the
spiral groove or vent groove 619a.
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Another design feature which is incorporated into the construction of electric
pump 600 (as well as electric pump 600a) pertains to the use of tamper-proof
threaded
fasteners. With reference to FIG. 27, threaded fasteners 638 and 642 include a
head
construction with a fluted recess 638a and 642a, respectively, as well as a
center post.
The unique shape of each recess 638a and 642a, along with the center post, is
such that
a special tool is required in order to install and remove these tamper-proof
threaded
fasteners. Conventional hand tools, such as flat blade screwdrivers, phillips
screwdrivers and allen wrenches are not suitable as a means to remove these
threaded
fasteners. Since these types of hand tools would be the types typically
available in the
field, providing a specialized shape which requires a special tool clearly
enables the
intention of providing these threaded fasteners as "tamper-proof' threaded
fasteners.
One of the design improvements offered by electric pump 600 is a more
compact construction by shortening the extended length of the inlet and outlet
conduits
644 and 646, respectively, relative to face 652 which abuts up against the
inner surface
of the hybrid module as hex head bolts 654 are tightened. As noted above,
there are
two embodiments, one embodiment has a four-bolt pattern (bolts 654) and the
other
embodiment has a three-bolt pattern. The referenced distance (d) (see FIG. 20)
is
approximately 69 mm. An earlier prototyped version of the disclosed electric
pump
600 set this dimension (d) at approximately 79 mm. This more compact design
results
in a smaller electric pump and a smaller electric pump has less weight. Less
weight
results in better fuel economy.
This earlier prototyped version also incorporated an alignment dowel pin as
part of one of the four hex head bolt locations. This "incorporated"
construction used a
hollow dowel and the corresponding hex head bolt extended through the dowel
(i.e.,
concentric) such that dowel alignment and bolting occurred essentially at the
same
axial location. Another design improvement added to electric pump 600 was to
separate the dowel pin 606 from the location of the corresponding hex head
bolt 654 as
now shown in FIGS. 12 and 18. A separate portion 656 is included as part of
the pump
body 620 for receiving and seating one end of dowel pin 606. This relocation
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contributes to a more accurate alignment procedure, a more accurate alignment
in the
resulting assembly, and less risk of interference as the hex head bolts are
tightened.
Another improvement introduced into electric pump 600 is a longer 0-ring
landing as compared to an earlier prototyped version. By "longer", what is
meant is
that the lateral section diameter of the 0-ring body is larger in the current
embodiment
as compared to the earlier prototyped version. In turn, this larger diameter
in lateral
section means that the receiving groove has a larger diameter and thus in an
axial or
longitudinal direction is "longer". Having a larger 0-ring provides more
elastomeric
material for compression and a larger area of sealing contact. The result is a
larger and
more effective sealing interface at the location of the 0-ring relative to the
hybrid
module.
Referring to FIG. 19, the connector 640 has a different orientation when used
with the three-bolt pattern illustrated in FIG. 12A. This revised orientation
makes
assembly and the electrical connections easier.
While the preferred embodiment of the invention has been illustrated and
described in the drawings and foregoing description, the same is to be
considered as
illustrative and not restrictive in character, it being understood that all
changes and
modifications that come within the spirit of the invention are desired to be
protected.
