Note: Descriptions are shown in the official language in which they were submitted.
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REMOTE ENGINE STOP/START SYSTEM WITH BACKUP MOTOR CONTROL
BACKGROUND OF THE INVENTION
1. Technical Field:
The invention relates to power take off systems for utility vehicles and more
particularly to
a system providing remote starting and stopping of the vehicle and for control
of an
emergency back up motor to the power take off system.
2. Description of the Problem:
Utility vehicles are often advantageously supplied with auxiliary equipment
the operation of
which is supported by the vehicle. Such auxiliary equipment can include
hydraulically
powered, aerial lift buckets that are often used for the repair of electrical
power distribution
lines. Typically, a hydraulic lift platform will be driven by a pump which is
in turn driven by
the vehicle's engine. In some applications, a back up prime mover, e.g. an
electrical motor,
is provided for the pump. A bucket at the end of the aerial lift system is
electrically isolated
to allow the worker to work on power lines which are still hot.
Trucks may come equipped with controls to allow a worker supported in the
bucket to
remotely shut off and tum on the vehicle's engine and to remotely raise and
lower the lift.
To avoid providing a conductive electrical path between the bucket and the
truck, the controls
located in and around the bucket for the operator's use are usually pneumatic.
An air line
is connected between the bucket, where a plunger-actuated piston is
positioned, and a
pneumatic, pressure actuated, electrical switch on the truck. To avoid expense
a minimal
number of pneumatic lines is provided. A problem addressed by the invention is
providing a
single, pneumatic, pressure actuated electrical switch which can be used to
both start and
stop a truck's engine and in some appiications, allow activation of a back up
hydraulic pump
in case of engine failure. Complicating the effort to construct such a device
is the
susceptibility of vehicle electronics to resetting during engine starting due
to voltage
fluctuations.
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Industry standards specify that the bucket control for an aerial lift truck
having an emergency or back up
pump shall: (1) if the engine is running and the remote switch is closed
(regardless of the duration for
which it is held closed), shut down the engine; (2) if the remote switch is
kept depressed for more than
3 seconds following a remote engine stop, cause the emergency or back up pump
to operate and to
continue to operate for as long as the switch is held closed; (3) if the
remote switch is cycled following a
remote stop or following the operation of the emergency pump, cause the engine
to crank for the
duration of the switch closure; and (4) if the engine does not start after
cranking, respond to cycling the
remote switch by causing the emergency pump to operate for as long as the
remote switch is
depressed.
Contemporary vehicles are commonly equipped with an electrical systems
controiler/body computer
(ESC) and a controller area network allowing data transfer between the ESC and
other controllers,
including an engine controller and a transmission controller. These systems
are built in conformance
with the Society of Automotive Engineers' J1939 standard. Remote engine and
bucket position control
must be implemented in a way that cranking and shut down of the engine is
effected only by closure of
a hard-wired, ground side switch. This remote switch must be designed in the
system hardware and be
independent of the ESC's software. The hardware architecture cannot depend
upon the ESC
remaining active during engine cranking and must continue to function even if
the ESC temporarily fails
and reinitializes due to transient low voltage.
The status of the ESC cannot be allowed to interfere with normal starting and
stopping of the engine
using the standard four-position key ignition switch. It must remain possible
to crank the engine even
when the vehicle is latched in the remote start mode. This allows ground
personnel to start the engine
and engage PTO operation to lower a boom should the operator be disabled. It
is permissible to allow
momentary cycling of the key ignition switch to cancel remote stop mode. The
system shall prevent
engine cranking in response to closure of the remote switch if the hood is
open. The hood disable
feature must also be independently operable without reference to ESC status.
However, the backup
pump motor must be operable with the hood open.
The backup motor and solenoid should not be operated for any cluration of
time, or briefly cycled on
and off, unless the conditions for emergency operation have been met. The
backup motor brushes and
solenoid contact life may be compromised by repeated, brief duration operation
at high surge current
levels. Remote switch operation should not result in application of any
current to the backup motor and
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solenoid unless and until its operation is necessary.
The system shall permit the engine to crank only so long as the remote switch
is closed. Once the
remote switch opens, cranking should immediately stop, allowing only for some
delay where the remote
switch is pneumatically actuated. The system shall not allow the engine to
crank unless the parking
brake is set. This requirement can be met by modification of ESC software. The
system shall not allow
remote engine shut down unless a J1939 compliant engine RPM rnessage is
present on the vehicle
databus from an engine controller. This requirement prevents stranding an
operator in a boom since
the engine will not crank remotely if an engine RPM message is not present.
SUMMARY OF THE INVENTION
According to the invention there is provided a motor vehicle having a remote
switch by which the
vehicle's engine may be shut down and restarted. In some applications the same
switch may be used
to engage a backup electric motor energized from the vehicle's battery as a
substitute prime mover for
a power take off apparatus installed on the vehicle. The inventiori provides a
vehicle engine ignition
control system having a starter solenoid and motor and engine control
electronics. A multiple position
ignition switch provides energization to the ignition control system in
response to positioning of a key
switch, as is conventional. The ignition switch has two output termirials
which assume energized states
in response to the positioning of the key switch. A first output is energized
when the key switch in
placed in a start position. A second output is energized when the key switch
is in either the ignition
position or the start position and may be energized when the key switch is in
an accessory position. A
remote switch is located on the vehicle away from the multiple position
ignition switch, typically in a
bucket suspended by an aerial boom. The remote switch provides a connection to
ground when
closed. An electrical systems controller communicates with the engine control
electronics and is
coupled to the remote switch to be responsive to closure of the remote switch
in accordance with its
programming. Responses include providing various enable signals and/or ground
connections
enabling operation of selected portions of the ignition control system. A
remote start relay is coupled to
respond to a remote start energization signal sourced by the electrical
systems controller if it occurs
concurrently with closure of the remote start switch. The remote start relay
provides an activation'*
signal on an output which is applied to a starter relay. The starter relay
responds to the activation
signal by providing activation energization to the starter solenoid and motor.
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Remote stop of the engine is provided by control of a chassis ignition relay,
which couples an ignition
signal (Ign) from the ignition switch to an engine controller. A remote switch
state detection relay is
coupled to the remote switch and to the second output of the multiposition
ignition switch and is
responsive to the concurrent occurrence of an energization signal on the
second output of the
multiposition ignition switch and closure of the remote switch to generate a
remote stop energization
signal. The electrical systems controller is further responsive to closure of
the remote switch and to
indication that the engine is operating (by reading an engine RPM signal from
the engine controller) for
providing a ground connection through an input. A remote stop relay provides
coupling of energization
from the multiple position ignition switch to the chassis ignition relay. The
chassis ignition relay is
connected to the remote switch state detection relay to receive the remote
stop relay energization
signal and is further connected to the input of the controller, the remote
stop relay being responsive to
the remote stop energization signal and grounding of the ground side of its
energization coil through the
controller input for interrupting energization of the chassis ignition relay
and thereby cutting the lgn
signal to the engine controller, resulting in interruption of operation of the
engine.
Where a vehicle is equipped with backup prime mover for a vehicle power take
off (PTO) apparatus,
the ignition system further includes a backup motor and solenoid connected to
the vehicle electrical
power source. A backup motor inhibit relay is connected across the power
connection to the backup
motor and solenoid to prevent any undesired operation of the motor, however
brief. A backup motor
relay is coupled to receive energization from the remote start relay and is
further coupled to the remote
switch to be responsive to concurrent closure of the remote switch and
application of the energization
signal from the remote start relay for coupling energization signal from the
remote start relay to the
backup motor inhibit relay as an input. Finaily the electricaf systems
controller provides a connection to
ground on an inhibit input in response to the key switch being in the ignition
position and engine
cranking having been attempted and failed.
Additional effects, features and advantages will be apparent in the written
description that follows.
BRIEF DESCRIPTION OF THE DRAWINGS
The novel features believed characteristic of the invention are set forth in
the appended claims. The
invention itself however, as well as a preferred mode of use, further objects
and advantages thereof,
will best be understood by reference to the following detailed description of
an illustrative embodiment
when read in conjunction with the accompanying drawings, wherein:
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Figure 1 is a simplified illustration of a truck mounted aerial lift assembly
for locating an operator in
various raised positions.
Figure 2 is a high level schematic of a vehicle electrical and hydraulic
control system incorporating the
invention for the truck of Fig.1.
Figure 3-10 are a series of circuit schematics of a remote ignition control
system in accordance with
two embodiments of the invention.
Figures 11-12 are high-level flow charts of programs executed by a system
electronics controller in
implementing aspects of the invention.
DETAILED DESCRIPTION OF THE INVENTION
Referring to the drawings, and particularly to FIG. 1, an example of a mobile
aerial lift truck 1 is
illustrated in simplified presentation for clarity of illustration. The
niobile aerial lift truck 1 includes an
aerial lift unit 2 mounted to a bed on the back portion of the truck. The
aerial lift unit 2 includes a lower
boom 3 and an upper boom 4 pivotally interconnected to each other and to the
truck bed through
support 6 and rotatable support bracket 7. A bucket/basket 5 is shown secured
to the outer end of the
upper boom 4 within which the operating personnel are located during the
lifting to and locating within a
selected work area in accordance with known practice. Basket 5 is typically
pivotally attached to the out
end of the boom 4 to maintain a horizontal (level) orientation at all times.
The aerial lift unit 2 is
mounted to the truck bed through support 6. A rotatable support bracket 7 is
secured to the support 6
and projects upwardly. The lower boom 3 is pivotally connected as at pivot 8,
to the rotatable support
bracket 7. A lifting lower boom cylinder unit 9 is interconnected between
bracket 7 and the lower boom
3. In the illustrated embodiment, a pivot connection 10 connects the lower
boom cylinder 11 of unit 9 to
the bracket 7. A cylinder rod 12 extends from the cylinder 11 and is pivotally
connected to the boom 3
through a pivot 13. Lower boom cylinder unit 9 is connected to either of two
hydraulic supplies of a
suitable hydraulic fluid, which allow the assembly to be lifted and lowered as
desired.
The outer end of the lower boom 3 is interconnected to the lower and pivot end
of the upper boom 4. A
pivot 116 interconnects the outer end of the lower boom 3 to the pivot end of
upper boom. An upper
boom/compensating cylinder unit or assembly 117 is connected between the lower
boom 3 and the
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upper boom for pivoting the upper boom about pivot 116 for positioning of the
upper boom relative to
the lower boom. The upper boom/compensating cylinder unit 117 is constructed
to permit independent
movement of the upper boom 4 relative to boom 3 and to provide a compensating
motion between the
booms to maintain the upper boom raising with the lower boom and is similarly
connected to the
sources of pressurized hydraulic fluid as further developed below.
Conventionally, aerial lift unit 2
requires positive hydraulic pressure both to be lifted or to be lowered.
Bucket 5 includes a plunger
moving a piston in an air line. The air line runs from bucket 5 to a point on
truck 1 where a remote
switch, as described below, is located.
Fig. 2 is a block diagram schematic illustrating electronic control of a truck
1, based on controller area
network technology and an electrical systems controller/body computer (ESC)
24. Collectively,
bus/data link 18 and the various nodes (generally the various vocational
controllers described below) to
which it is attached form the controller area network (CAN), which conforms to
the SAE J1939
standard. Controller area networks are networks which do not have destination
addresses for nodes
attached to the networks, but rather provide for transmission of data in
packets, identified as to the
source, message type and priority. The nodes are programmed as to whether to
respond to a packet
based on one or more of three identifiers. Many message types are predefined
by the SAE J1939
standard. The SAE J1939 standard allows the definition of proprietary message
types which in
structure conform to the standard.
Active vehicle components are typically controlled by one of a group of
autonomous, vocational
controllers. These vocational controllers include ESC 24, an engine controller
20, a electrical gauge
controller 14, a transmission controller 16, an anti-lock brake system
controller 22, and a remote power
take off controller 57. ESC 24 and engine controller 20 are of primary
interest to the present invention.
Transmission controller 16 is provided with vehicles equipped with automatic
transmissions and
generates a signal indicating whether the vehicle's drive line is engaged or
not. It is preferred at the
time this application is being written that application of the invention be
limited to vehicles equipped with
automatic transmissions due to the lack of a indicator on vehicles ecluipped
with standard transmissions
as to whether the vehicle drive line is disengaged. Should such an indicator
be made available the
invention can be used on vehicles equipped with standard transmissions. Engine
controller 30 provides
an engine RPM signal, which is required for implementing certain routines in
ESC 24. The engine
controller 20 also receives certain signals implicated in engine operation.
ESC 24, through discrete
input ports 50 and output ports 52, provides selective enable siginals and
ground connections, and
detects the state of a remote switch used for remotely starting and stopping
the vehicle's engine.
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The hydraulic lift unit 58 which supports operation of an aedal lift unit 2 is
primarily powered by a
conventional PTO hydraulic pump 60 which is usually driven by engine 30.
Backup to engine 30 for
powering hydraulic pump 60 is provided by a backup solenoid and motor 54,
energized from vehicle
battery 21. Energization of backup solenoid and motor 54 is controlled in part
by programming of ESC
24 and control signals issued by it through discrete outputs 52 coupled into
the starter system 100 and
a pump inhibit relay 46. Energization for backup solenoid and motor 54 is
supplied by battery 21 as
controlled by a pump relay 36 and the pump inhibit relay 46. ESC 24 also
controls remote starting and
stopping of engine 30 by control signals provided to starter system 100 which
in tum provides control
signals to a starter solenoid and motor 59 and engine controller 20. Battery
21 charge is maintained by
an engine 30 driven charging system 47. ESC 24 also monitors the position of a
parking brake and a
PTO on/off switch. PTO on/off switch is located in a muitiplexed switch pack
43, monitored on the
J1708 switch data link 49. The parking brake is a discrete switch input 50.
Referring to Figures 3-7, a preferred embodiment of the starter system 100 as
applied to a vehicle not
having a backup hydraulic pump motor is illustrated. Starter system 100
provides for starting and
stopping an intemal combustion engine 30 from either inside a vehicle cab
using an ignition switch 102
or from a remote point on the vehicle using a remote switch 110. Remote switch
110 is a ground side,
momentary contact switch with a default open state. Remote switch 110 is
pneiamatically actuated
using a plunger 117 into an air line 111. Ignition switch 102, as is
conventional, has four position: (1)
accessory/Acc; (2) off; (3) ignition; and (4) start. Ignition switch 102 has
first and second mechanically
linked switches 106 and 108. Switch 106 has an output connected to the start
contact of the switch.
For switch 108 the ignition and start position are tied together for output
115. Ignition and
AccessorylAcc positions are tied together when the key switch is either of
these positions.
Accessory/Acc is a discrete input to the ESC 24. Acc has +12V anytime the key
is in the accessory or
ignition positions. Accessory drops out with the key switch in the crank
position, which permits the
invention to detect that the key switch is in the crank position during a
remote stop period, such as the
case where someone in the cab cranks the engine should the operator in the
boom not be able to start
the engine remotely (e.g. when the operator is unable to press the remote
button. Switch 108, as
described below, allows for remote stopping and starting of an engine using
remote switch 110.
Ignition switch 102 is key actuated and is energized through a 5 amp fuse 104
from battery 21. For
clarity of presentation, the off and ignition contacts for switch 106 are
shown as floating, their operation
not effecting the invention. The accessory contact of switch 106 provides
power as an input to the ESC
24.
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Remote switch 110, ignition switch 102 and the various relays used in
implementing starter system 100
interact with programmable controllers which communicate with one another over
the J1939 datalink
18. ESC 24 and engine controller 20 monitor the state of various signals and
provide enabling signals
(including signals characterized by a ground connection througli the
controller) which implement
aspects of the invention. Transmission controller 16 provides a driveline
engagement indication signal
used by engine controller 20 which inhibits cranking should the transmission
engagement signal
indicate the transmission (not shown) is in neutral or park. Some operations
of starter system 100 can
however be invoked notwithstanding temporary failure of the programmable
controllers. ESC 24 is
illustrated sectioned into two parts, one associated with electrical
connections outside of a vehicle cab
and a second section inside the vehicle cab. ESC 24 is usually orie device and
the division is simply
for convenience of illustration. Adapting starter system 100 for remote
operation must be done in a way
that does not change normal operation of a vehicle. Accordingly, switch 106,
when moved to the start
position, supplies power to a sense input (PIN 86) of starter relay 112. This
causes starter relay 144 to
close thus supplying power from battery 21 through fuse 144 to the output
associated with PIN 87 of
the starter relay and from there to a starter solenoid and motor 59. Engine
controller 20 provides a
ground to PIN 85 of starter relay 112 through a transistor switch 126 which is
biased into conductivity in
response to a gate signal provided by microprocessor 124.
Remote operation is possible when ignition switch 102 is placed in the
"ignition position". This places
both of switches 106 and 108 in the ignition position, supplying power to node
115 which is tied to the
second output of ignition switch 102. Remote operation is involked by closing
momentary contact
remote switch 110, the effect of which is to connect to ground node 113, which
is normally biased high
by ESC 24 from a sensor input 130. The closure of remote switch 110 is
detected by ESC 24 through
sensor input 130. The closure of remote switch 110 also grounds thie ground
side contact for the sense
coil of a remote start relay 138 and the ground side contact for the sense
coil of a remote switch state
detect relay 132. Assuming initially that engine 30 is running, the closure of
remote switch 110 results
in engine 30 being shut down. Since switch 108 is in the ignition position
power flows from node 115 to
the high side contact for the sense coil for remote switch state detect relay
132, and the relay closes,
supplying power from ignition switch 102 through remote switch state detect
relay 132 to the high side
sense input of remote stop relay 114.
Upon detection of closure of remote switch 110 ESC 24 determines if the
conditions for remote stop are
present, e.g. (1) parking brake set, (2) Engine RPM signal non-zero, etc. If
all the conditions are met,
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ESC 24 will provide a ground connection through transistor 132 (an RD1 5 low
side driver) to the low
side contact for the sense coil of remote stop relay 114, resuiting in the
relay opening and the transfer
of power through the remote stop relay being interrupted. When remote stop
relay 114 opens, three
ignition relays 116, 118 and 120 are all interrupted, with the result that
power to all ignition powered
features of the vehicle are interrupted. Chassis ignition relay 116 provides
an ignition signal (Ign) via
fuse 122 to engine controller 20 and microprocessor 124. Engine controller 20
in turn carries out a shut
down of engine 30. Power is also interrupted to transmission controller 16.
When the user releases remote switch 110, DIN 19 on ESC 24 detects an increase
in voltage at node
113 indicating to ESC 24 that the remote switch has opened. Remote switch
state detect relay 132 is
deenergized due to loss of a connection to ground on the low side of the
switch state detect relay's
sense coil. Remote stop relay 114 remains energized (i.e. latched) because the
high side of the remote
stop relay sense coil is tied to DIN $7 of the relay and ESC 24 continues to
provide a ground
connection to the low side of the remote stop relay's coil.
Remote start is explained with reference to Fig. 4. Again a user causes remote
switch 110 to close and
holds the remote switch down. Engine 30 cranks for as long as remote switch
110 is held closed.
Upon closure of remote switch 110 node 113 drops to ground, an event which is
detected by sensor
130 (DIN 19) of ESC 24. The voltage drop causes remote switchi state detect
relay 132 to trip to a
closed state, an operation which has no other effect on circuit operation. In
response to the fall in
voltage ESC 24 determines if the conditions for remote start are met. If the
conditions are met, ESC 24
removes the gate voltage from transistor 134 cutting off conduction through
the device. At this point the
remote stop relay 114 deenergizes, reconnecting the high sides of the
energization coils for the three
ignition relays 116, 118 and 120, to power from multiple position ignition
switch 102. The low side
contacts for the sense coils for all three of the ignition relays 116, 118 and
120 are connected
permanently to chassis ground so all three relays are automatically
reenergized. The signal fgn to
engine controller 20 is thus restored and transistor 126 is energized to
connect the ground side of the
energization coil of starter relay 112 to ground. Ign also indicates to the
engine controller 20 that other
ignition management functions are to be implemented.
ESC 24 must carry out certain actions to enable an engine restart in response
to closure of remote
switch 110. The response to the detected voltage drop on node 113 includes ESC
24 driving output
136 high. With output 136 high and node 1131ow, a voltage difference appears
across the contacts of
the sense coil for remote start relay 138 and the relay becomes energized.
Provided the vehicle hood
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is closed (thus closing a hood safety switch 142), power will be coupled
through remote start relay 138
to the sense coil high side input (DIN 86) of starter relay 112 from node 115
with the key switch of the
multiple position ignition switch 102 in the ignition (ign) position. With
starter relay 112 energized,
energy is coupled through the starter relay from battery 21 to starter
solenoid and motor 59 to initiate
cranking.
High surge currents delivered to starter solenoid and motor 59 may cause a
system voltage drop which
may result in ESC 24 resetting. If this occurs transistor 134 remains in a non-
conductive state which is
desired. However, output 136 can fail. Accordingly, it is desirable to provide
a means of latching
remote start relay 138 in an energized state for cranking, since crariking
will cease if remote start relay
138 deenergizes in response to loss of the signal from output 136. See Figure
6. To effect latching of
remote start relay 138 a diode 140 is provided oriented to conduct electricity
from DIN 87 (the normally
open contact) of remote start relay 138 to the high side contact of the
energization coil for the relay.
Once remote start relay 138 is energized, and for as long as remote switch 110
is closed, the relay will
remain latched by way of a forward biased diode 140. This of course requires
the ignition switch 102
remain in the Ign or St position. If Ignition switch 102 is moved to the OFF
position, it will of course
deprive the output DIN 87 of power and remote start relay 138 will be
deengergized. Release of
remote switch 110 deprives the ground side contact of the energization coil of
the remote start relay of
a ground connection also resulting in deenergization of the relay. See Figure
7.
A diode 140 is used instead of a wire connection to provide a latch mechanism
for remote start relay
138. Were a wire used to connect the contacts of remote start relay 138,
anytime a high signal
appeared on output 136 of ESC 24 the engine would crank. Since ESC 24 is
subject to reprogramming
and field maintenance the possibility that the device could be reprogrammed or
rewired cannot be
discounted. The engine crank inhibit low side driver (sensor input 130) is a
relatively low impedance
path to ground from node 113 when the transmission is in neutral. It could
function to pull down node
113 enough to be detected as closed remote switch.
Referring to Figures 8-10 a second embodiment of the invention incorporating
an emergency pump
motor and solenoid 54 is described. The remote start/stop circuit 100 of
Figures 3-7 is unchanged
except for the addition of the emergency motor and associated control relays.
As with the remote start
operation, operation of the emergency motor is to be invoked using remote
switch 110. An additional
connection to ESC 24 is also provided to allow ESC 24 a certain degree of
control over remote
operation of emergency pump motor and solenoid 54 although the circuit
provides for failsafe operation
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of the emergency pump motor should ESC 24 fail.
Normally the operation of emergency pump motor and solenoid 54 is inhibited by
ESC 24. This is
effected by ESC 24 energizing transistor 146 to provide a pump inhibit signal
(a ground contact) to the
low side contact of the energization coil of pump inhibit relay 46. The high
side contact of the
energization coil of pump inhibit relay 46 is connected to node 115. As a
result, pump inhibit relay is
energized and no activation signal can flow from the relay to emergency pump
and solenoid 54. See
Figure 8.
Emergency pump operation following a remote stop occurs when a user/operator
keeps remote switch
110 depressed after a remote engine shut down. Remote start relay 138 is not
energized, so ignition
voltage is supplied from multiple position ignition switch 102 via node 115 to
the high side sense coil
contact of pump relay 36 energization coil and to the power input contact of
the pump relay, the two
contacts being in common. See Figure 9. With the ground side contact of the
energization coil of
pump relay 36 at ground, the response of pump relay 36 is to energize
supplying power to DIN 30
(common terminal) of pump inhibit relay 54.
ESC 24 times the duration of closure of remote switch 110 and when three
seconds have expired
deenergizes transistor 146 depriving a connection to ground for the ground
side contact of the
energization coil of pump inhibit relay 46. Pump inhibit relay 46 deenergizes
connecting the common
terminal of the relay to output DIN 87A and thereby supplying an activation
signal to emergency pump
motor and solenoid 54. See Figure 10. The deenergized pump inhibit relay 46
supplies ignition
voltage to the emergency pump motor solenoid resulting in energization of the
emergency pump motor.
Emergency pump motor and solenoid 54 operates as long as remote switch 110 is
held closed.
Opening remote switch 110 causes pump relay 36 to deenergize, interrupting the
signal to the common
terminal of pump inhibit relay 46 which in turn deenergizes depriving
emergency pump motor and
solenoid 54 of an activation signal. In addition, when remote switch 110 is
released the voltage on
node 113 increases, which is detected by ESC 24 which responds by energizing
transistor 146 and
thereby energizing pump inhibit relay 46 until ESC 24 again determines that
the conditions for
emergency pump motor operation are met. Were there no pump inhibit relay 46,
any closure of remote
switch 110 would cause emergency pump motor and solenoid 54 to briefly
operate, which has the
potential of decreasing the life of the solenoid and motor.
Operation of emergency pump motor and solenoid 54 can also occur after an
unsuccessful engine
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crank. ESC 24 maintains pump inhibit relay 46 in an energized state until the
conditions for emergency
pump motor and soienoid 54 operation are met. Following a crank attempt which
fails, an operator
reieases remote switch 110 to discontinue cranking. The operator then
depresses remote switch 110
and holds it closed to initiate operation of the emergency pump motor and
solenoid 54. See Figure 9.
ESC 24 will detect the closed remote switch 110. Even though the erigine is
not running, ESC 24 does
not initiate a crank operation (by supplying the appropriate signals at output
136 and changing the state
of transistor 134) since the last command was to crank the engine. ESC 24 is
programmed instead to
engage emergency pump motor and solenoid 54 following a failed cranking
attempt, even if ESC 24
suffered a reset due to low battery voltage during cranking. Three seconds
after remote switch 110 is
closed ESC 24 deenergizes transistor RD13 146. This in turn deenergizes pump
inhibit relay 46.
Closure of remote switch 110 has already supplied a ground connection to the
ground side contact of
the energization coil of pump relay 36, resulting in the pump relay becoming
energized. Deenergized
pump inhibit relay 46 supplies ignition voltage from pump relay 36 to
emergency pump motor and
solenoid 54 and the emergency pump motor begins to operate until remote switch
110 is released.
Opening of remote switch 110 causes pump relay 36 to deenergize, interrupting
ignition voltage to
pump inhibit relay 46 and cutting off power to emergency pump motor and
solenoid 54. Pump inhibit
relay 46 remains energized by a reenergized RD 13 transistor 146 until the
conditions for emergency
pump motor operation are again met.
Emergency pump motor and solenoid 54 operation are also available in case of a
complete failure of
ESC 24. If ESC 24 fails, the pump inhibit signal from RD 13 transistor 146
also fails and the pump
inhibit relay 46 deenergizes. If battery voltage is still available, ignition
voltage is still present on the
high side contact and common contact for the energization coil of pump relay
36. When remote switch
110 is depressed pump relay 36 energizes and couples ignition voltage through
to the common contact
of now deenergized pump inhibit relay 46. Pump inhibit relay couples the
ignition voltage through to
emergency pump motor and solenoid 54 which is energized whenever, and for as
long as, remote
switch 110 is closed. No three-second delay occurs for pump operation under
conditions of failure of
ESC 24.
Figures 11 and 12 are flow charts for programming of ESC 24 to implement
certain features of the
present invention for the embodiment not incorporating and the alternative
embodiment incorporating
an emergency pump motor, respectively. The programs implement logical testing
for the conditions
under which the vehicle's engine is stopped or started and the emergency pump
motor is run. When
the conditions for an engine stop are met ESC 24 provides the required signals
for invoking particular
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operations. For example, for a remote engine stop, a 1 amp FET low side driver
associated with ESC
output 136 is deactivated and remote stop relay 114 is activated aind remains
activated until either
multiple position ignition switch 102 is moved to OFF or an engine crank
sequence has begun. For a
vehicle equipped with an emergency pump motor the remote stop relay 114
remains activated until the
ignition switch is turned to off, or the remote switch 110 is held closed for
a period exceeding a delay
period, or an engine crank is requested. Programming helps determine if the
conditions for an engine
stop are met, which are: (1) the engine is running; (2) the multiple position
ignition switch is NOT in the
OFF position; (3) remote switch 110 is depressed; (4) the remote switch 110
has just been depressed;
(5) the park brake is set; (6) the status of the engine speed message signal
is good; and (7) if a PTO
interlock variable is set, the PT0 switch is on and has good status. Where the
vehicle is equipped with
an emergency pump motor then the last condition (no. 7) is simply that the
status of the engine speed
signal is good. When the engine controller determines that the engine has
started it discontinues
cranking.
The engine can be remotely started under the following conditions: (1) The
engine is not running; (2)
the key is not in the OFF position; (3) the plunger switch is depressed; (4)
the plunger switch has just
been depressed; (5) the park brake is set; and (6) if the PTO interlock is
set, then the PTO switch is on
and has good status. For a vehicle with an emergency pump motor condition 6 is
replaced with the
condition that: the previous sequence with the engine not running was an
emergency pump motor
operation sequence or the previous sequence was an engine stop sequence using
remote switch 110.
Emergency pump motor inhibit relay 46 is activated when ignition switch 102 is
not in the off position
and any one of the three following conditions is met: (1) the accessory signal
is ON and NEW, or (2)
the engine state is ON and NEW, or (3) the remote switch 110 has just been
released. Pump inhibit
relay 46 is deactivated when the ignition switch 102 is OFF or all of the
following conditions are met: (1)
ignition switch 102 is not OFF; (2) remote switch 110 is closed; (3) remote
switch 110 has been closed
for longer that the programmed delay period after stopping the engine to run
the emergency pump
motor 59. Finally, if an emergency pump motor is present it will also run if
the multiple position ignition
switch 102 is not in the OFF position, the remote switch 110 is depressed, no
other functions are
currently running (engine stop, cranking, etc.) and the conditions are such
that no other function will
run.
Referring particularly to Figure 11, execution of the program for a vehicle
not having an emergency
pump motor begins with determination at step 200 of the position of the
ignition switch. If the ignition
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switch is not in the OFF position the Key_State is true and execution
continues to step 202. If NO the
variables Engine_Stop_Relay_Cmd and Engine_Crank__Cmd are reset at step 222
and processing
stops. At step 202 ESC 24 determines if remote switch 110 is depressed. If no,
the
Engine_Crank_Cmd variable is reset at step 224 and processing stops. If a yes
resulted at step 202,
execution continues to step 204 where the value of the variable
"Tem_Rem_Start_Stop_Plunger" is
checked. If the value is "NEVM', i.e. the remote switch is newly depressed a
value of 1 is stored on a
stack in memory, otherwise a value of 0 is entered. A logical AND operation is
then implemented on
the stack. Next, at step 206 it is determined in the remote stop start PTO
interlock is set. If the PTO
interlock is set, step 208 is executed to determine if the PTO engagement
switch is on and a logical
AND operation is performed with 1 and the stack. Otherwise the stack is
"ANDed" with 0. At step 210,
following step 208 or along the NO branch from step 206, it is determined if
the Parking brake is
engaged. If yes the stack is ANDed with 1, otherwise with zero. Next, at step
212, if the ignition signal
(Ign) to engine controller is on an "AND" operation is preformed on the stack
with 1 if the Engine_State
has a good status. Otherwise the AND operation on the stack uses a 0. Next, at
step 214 the stack is
interrogated to see if it has the value 1. If NO the conditions for remote
start or stop have not been met
and processing is exited. If YES, the conditions for a remote stop or start
have been met and step 216
is executed to determine if the engine is running. If YES, the
Engine_Stop_Relay_Cmd is set and
transistor RD15 134 is energized. If NO, the engine stop relay command is
reset and engine crank
command is issued on output 136.
The required logic is more complex if an emergency pump motor is provided.
Referring to Figure 12 a
flow chart for a vehicle equipped with an emergency pump motor is illustrated.
Again processing
begins with a determination of the key state at step 230 (i.e, the key is not
in the OFF position). If the
key is in the OFF position (the NO branch), step 268 is executed to reset each
of four variables: (1)
Engine_Crank_Cmd; (2) Engine_Stop_Relay_Cmd; (3) EmergencyPump_Inhibit_Relay;
and (4)
Start_Stop_Timer and the process is terminated. Otherwise processing continues
to step 232 which
tests to see if one of three conditions is met: (1) if the Accessory_Signal is
on or new (in this version the
invention also works for ACC being on in the ignition switch 102); (2) the
Engine state is on or new; or
(3) the remote switch is newly open. If yes, step 234 is executed to set the
emergency pump motor
relay and to stop the remote switch closed timer. Following the NO branch from
step 232 or after step
234 it is determined if the remote switch is closed. If NO, the routine is
exited via step 270 with reset of
the engine crank command and the remote switch closure timer. Otherwise step
238 is executed to
determine if the remote switch timer has expired. If yes, the process is
exited via step 272 with a reset
of the emergency pump motor inhibit relay and turning off the timer.
Otherwise, along the NO branch
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from step 238, step 240 is executed to put a 1 on the stack if the remote
switch is newly closed, Next,
at step 242, if the parameter remote stop/start PTO interlock is set, an AND
operation is performed
between the stack and 1, but only if the PTO engagement switch is on and has a
good status.
Otherwise an AND operation is performed between the stack and 0. Next, at step
244, an AND
operation between the stack and 1 is done if the parking brake is set, but
otherwise with 0.
Next, at step 246 it is determined if the signal Ign is high (as reported by
the Engine Controller). If YES,
step 248 is executed to determine if the engine status is bad and the remote
switch is newly depressed.
If YES, step 250 provides that a remote shut down flag be set and remote
switch depression timer be
started along with a stop timer. Following either the NO branch from step 248
or after step 250, if
engine status is bad an AND operation between the stack and 0 is done, but
otherwise the AND
operation is done against 1. Next, along the NO branch rom step 246 or after
step 252, the value of
stack is compared to 1. If it is not 1, processing ceases. Otherwise, along
the YES branch it is
determined if the engine state is true. If YES, the engine stop relay command
and remote shut down
flags are set. The remote switch closure timer is started and the engine stop
timer is started and
processing stops. Following the NO branch from step 256, the remote switch
timer is stopped and the
engine stop relay command is reset. Next, at step 262 it is determined if the
remote shut down flag is
set. If YES, the engine crank command is reset and the remote shut down flag
is reset. If NO, the
remote shut down flag is set, the remote switch timer is started and the
remote switch time. Processing
then discontinues.
The present invention provides a simple, multifunction remote start/stop
control system for a utility
vehicle that exhibits robustness. A single control may be used to invoke not
only starting and stopping,
but also to actuate an electric motor-driven pump in case of engine faiYure.
While the invention is shown in only one of its forms, it is not thus limited
but is susceptible to various
changes and modifications without departing from the spirit and scope of the
invention.
