Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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The invention relates to an apparatus for heating
the operating cabin of a machine drlven by an internal-
combustion en~ine, more particularly -the driver's compartrnent
of a vehicle, the said apparatus comprisiny a hydraulic pump
driven by the said enyine and drawiny engine-oil from the
engine lubricating- and cooling-oil sys-tern, a throttle-
element for r~ising the ternperature, connected to the sai~
hydraulic pump' an oil/air heat-exchanger in the driver's
compartment connected to the engine lubricating- and cooling-
oil system downstream of the throttle-element, as seen in
the direction of flow, and an adjustable flow-divider
controlling a bypass-line running to the said oil/air heat-
exchanger. Heating apparatuses of this kind are of partic-
ular advantage in the case of air-cooled internal-combustion
engines.
German OS 29 32 448 discloses a heating apparatus
in which the lubricating-oil-, cooling-oil- and heating-
circuits are completely separate, at least from the suction-
side of the hydraulic pump. Although in this case slightly
heated engine-oil is available to the heating-circuit heat-
exchanger as soon as the engine is started, the desired
high temperature at the engine-bearing locations arises only
as the total supply of lubricating-oil gradually heats up.
P 29 32 448.9 describes a heating apparatus in
which only a part of the lubricating-oil supply is repeatedly
throttled in order to accelerate the rise in temperature in
the heating-circuit heat-exchanger, but the total volume of
oil again heats up only gradually and this is detrimental to
the bearing locations. Moreover, a separate flow-divider is
needed to control this repeatedly throttled part-volume of
oil
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It is the purpose of the pre~ent invention to propose
a heating apparatus which not only adapts well to ex.istiny
lubrication oil systems, but also allows the increase in
temperature obtained by throttling to be used in full to
benefit, selectively or simultaneously, the heating-circuit
heat-exchanger, the bearing locations, and the ~plash-lubri-
cation locations, It is also the purpose of the invention,
while still maintaining the above-mentioned adaptability to
existing lubricating-oil systems, to make it possib]e to heat
up a part of the lubricating oil to an increased extent, the
amount of oil thus heated up being self-regulating without a
separate control-element.
The first of these purposes is accomplished by
providing an apparatus for heating the operating cabin of a
machine driven by an internal~combustion engine, more partic-
ularly the driver's compartment of a vehicle, the said
apparatus comprising a hydraulic pump driven by the said
engine and drawing engine-oil from the engine lubricating-
and cooling-oil system, a throttle-element for raising the
temperature, connected to the said hydraulic pump; an oil/air
heat-exchanger in the driver's compartment connected to the
engine lubricating- and cooling-oil system downstream of the
throttle-element, as seen in the direction of flow; and an
adjustable flow-divider controlli.ng a bypass-line running to
the said oil/air heat-exchanger, characterized in that the
return from the oil/air heat-exchanger is connected, at a
discharge-location-junction , arranged before the oil-
supply points to the engine, to the engine lubricating-
and cooling-oil system.
The second of these purposes is accomplished by
providing an apparatus as mentioned directly above wherein the
--2--
suc-tion-side of the hydraulic pump is connected at a branch
point arranged downstream of the lubricatiny-oil supply pump
to the lubricating- and cooling-oil sys-tem.
The conversion of existing internal-combusti.on
engines to the arrangement in accordance with the invention
is greatly facilitated through the aspects of: (a) providing
a lubricating-oil radiator in the lubricating- and cooling-oil
system, upstream of the loop-line, or lines for the hydrlulic
pump, the throttle-elemenk the flow-divider, and the oil/air
heat-exchanger, and in that the branch-point and/or the discharge-
location-junction, and/or the hot-oil return and/or the hot-oi'
branch, are located in connecting parts between the internal-
combustion engine and the lubricating-oil radiator, and (b)
providing the flow-controller as a thermostat-valve-
In one aspect of the present invention there is providedan arrangement for heating the operator's cabin of a machine
driven by an internal combustion engine, comprising a lubricat-
ing - and cooling - oil distribution system of the engine having
oil distribution points, the system including a first hydraulic
pump for pumping oil fr~n the engine oil sump through pre-
ssurized lines of the system, a heating system connected in
series with the distribution system and including a second
h~draulic pump driven by the engine for withdrawing engine oil
from the distribution system and pumping the engine oil through
the heating system, an intake line leading into the second pump
and being connected into the distribution system at a ta]~e-off
point downstream of the first pump, a throttling element in the
heating system downstream of the second pump for reducing the
pressure and elevating the temperature of the engine oil
passing therethrough7 a space neat exchanger in the heating
system downstream of the throttling element for supplying heat
to the operator's cabin, a by-pass line in the heating system
by-passing the heat exchanger, an adjustable control element
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for selectively controlling the ~low o~ heated oil down~treamfrom the throttling element to the hea-t exchange~ or through
the by-pass line depending on the heating requirements of the
heating system, a return line leading frorn the heat exchanger
and connected into the distribution system at a junction point
upstream of the oil distributing points an~ upstream o~ the
take-off point, whereby the oil fed components o~ the engine
are imrnediately heated through the oil distributing poin-ts.
Figures 1-4 are diagrammatic outlines of apparatus
in accordance with the invention and showing design variations-
Regardless of the suction-location of the hydraulic
pump, it is particularly desirable, in view of the wear
arising in internal-combustion engines, to connect the return
from the heat-exchanger, to the lubricating- and cooling-oil
system, before or upstream of the oil-feed locations, since
in this way when the heat-exchanger is in operation ? but
especially when it is being by-passed, heated lubricating-oil
imrnediately reaches the bearing locations through the bypass,
and components which are splash-lubricated through nozzles,
more particularly pistons, are, as usual, cooled only slightly
and thus reach their operating temperature more rapidly.
Further advantages according to the invention may be obtained
by connecting the suction-side of the hydraulic pump to the
lubricating-oil and cooling-oil system. In this connection
it is largely irrelevant whether the junction to the hydraulic
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pump is located before i.e. upstream of or after i. e. down-
stream of the discharge location-junction from -the heating-
circuit heat-exchanger in the main oil-sys-tem. Even in the
ease of the loops according to Figs 1 and 2, runniny parallel
with the main direction of flow, a return~flow takes plaee in
the section of main line located between the junc-tion-points,
if it is assumed that the displacemen-t of the internal-
eombustion engine is less than the output from the hydral~lic
pump. It is thus elearly recognizable, especially in ~'lgs.
3 and 4, that in all of the design~variants shown, there oceurs
a short-eircuit flow, the volume of which controls itself
automatically and which assists in accelerating the increase
in temperature, both in the heating-eircuit heat-exchanger
and at the engine oil-supply locations.
Adaptation of the heating apparatus aceording to
the invention to existing internal-combustion-engine design
is greatly facilitated in that the loops pertaining to the
heating-circuit are connected at pcints where portions of the
lubrieating-oil and cooling-oil system emerge from the engine
housing to be conneeted to external assemblies, on the one
hand, at the junetion between the engine and the lubrieating-
oil cooler and, on the other hand, at the junction between
the engine and the lubricating-oil filter. The conneetion may
be in aecordanee with the various arrangements shown. Partic-
ularly advantageous are arrangements whereby the lubricating-
oil passing to the heat-exchanger is also filtered before
entering it,the said oil also being filtered repeatedly as it
eirculates repeatedly in the loop.
The flow-divider aeeording to the invention may be
located, as desired, at the flow-division, as shown, or at
the confluence in the heat-exchanger bypass. Adjustment of the
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flow divider may be effected thermostaticall~ in accordance
with the heating requirements, using lubricating-oil ternpera-
ture or a room-tempera-ture as the control factor. It is also
conceivable to provide additional con-trol-means, e.g. for
shutting the heat off permanently regardless of the temperature.
In order to assure lubrication of the engine, activation of
the heat-exchanger may also be eliminated, below a minimal
lubricating-oil pressure, by over-riding the temperature-
control at the flow-controller, On the other hand, the heat-
ing-circuit heat-exchanger may also serve as a replacement for
a lubricating-oil radiator, if the flow of air to be processed
is also taken from outside the driver's cabin.
The hydraulic pump is usually coupled permanently
to the engine, for example, to an auxiliary take-off. A
variable drive is also conceivable, but is usually too complex
and thus costly for practical application. Furthermore,
arrangements of this kind have already been described.
When the maximal permissible lubricating-oil tempera-
ture is reached, if the hydraulic pump is in constant operation,
and especially at high amhient temperatures, throttling should
be eliminated, this being accomplished by control-means, not
shown, at the throttle. The designs shown are intended to
mean that either the throttle cross-section is controllable
or the throttle-element has an internal bypass.
Control of the throttle cross-section, or bypass,
may be effected by the previously described, precontrolled,
temperature- and viscosity-sensitive pressure-maintaining
valves. If control is to be effected as a function of other
operating parameters, e.g. component-temperature or engine-
loading, a solenoid-valve may be used for the purpose, and
this will preferably influence a precontrol device.
Various de~igns of the ~ppa~atus accordiny to the
invention appear in the four drawings attached hereto in which
differently arranged elements bear the same reference numerals.
The only differences are in the branch-points and discharge
locations. Each figure shows a lubricating- and cooling-oil
system in which lubricating-oil is -taken :rom an oil-tank 1 by
a lubricating-oil pump 2 and is delivered through a lubricating
oil radiator 3, and a lubricating-oil filter 4, to supply
points 5 of the internal-combustion engine. Provided i.n the
lubricating- and cooling-oil system is a branch-point 6, to
which a hydraulic pump 7 is connected, followed by a throttle-
element ~.
Running in parallel with a heat--exchanger 12 is a
bypass 13 controlled by a flow-divider 14. It is possible to
arrange hydraulic pump 7 and throttle-element 8 in a first
loop 10, and heat-exchanger 12 and flow-divider 14 in a
second loop 15 (Figs 2, 4) or to arrange alL of these compo-
nents in series in a common loop 20 (Figs 1,3). The
lubricating-oil emerging from heat-exchanger 12 and bypass
13 may be filtered entirely, or additionally, through an
auxiliary filter 17 (Fig. 1) within this loop 15,20, A non-
return valve 18 may be provided in the line running to heat-
exchanger 12, for the purpose of avoiding leakage when bypass
13 is open. Heat-exchanger 12 may also be protected from
overpressure by a short-circuit valve 19 (Fig. 3). The return-
flow from the said heat exchanger to the lubricating- and cool-
ing-oil system is effected at a discharge-location-junction
160 There is usually a return-flow between discharge-
location-junction 16 and branch-point 6. If the heating
30 system consists, as in Figs 2 and 4, of two loops 10 and 15,
loop 10, which contains hydraulic pump 7 and throttle-element
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8, terminates at a hot-oil return 9. In this case, loop 15,
containing heat-exchanger 12, starts at a hot-oil junction ll
which is usually arranged in the lubricating- and cooling-oil
system after hot-oil return 9. I~he li.ne cross-sections are
to be designed in such a manner as to ensure an adequate
flow through the said heat-exchanger, especially when the
apparatus is divided into two loops 10,15. In this latter
design it is possible, uncler certain circumstances, to ornlt
the direct connection between hot-oil branch ll and discharge-
location-junction 16 in the lubricating- ancd cooling-oil
system, but hi.s should not be done if the installation is to
be adapted to an existing internal-cornbustion engine. Modifi-
cation of the designs shown, with respect to the arrangement
of the flow-divider and the design of the throttle-element,
have already been described.
