WO1996032570A1 - Water-cooled diesel engine oil system - Google Patents

Water-cooled diesel engine oil system Download PDF

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Publication number
WO1996032570A1
WO1996032570A1 PCT/SE1996/000435 SE9600435W WO9632570A1 WO 1996032570 A1 WO1996032570 A1 WO 1996032570A1 SE 9600435 W SE9600435 W SE 9600435W WO 9632570 A1 WO9632570 A1 WO 9632570A1
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WO
WIPO (PCT)
Prior art keywords
driven gearwheel
housing
assembly
oil circuit
chamber
Prior art date
Application number
PCT/SE1996/000435
Other languages
French (fr)
Inventor
Nils Olof HÅKANSSON
Lars Tenglud
Original Assignee
Ab Volvo
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Ab Volvo filed Critical Ab Volvo
Publication of WO1996032570A1 publication Critical patent/WO1996032570A1/en

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C14/00—Control of, monitoring of, or safety arrangements for, machines, pumps or pumping installations
    • F04C14/18—Control of, monitoring of, or safety arrangements for, machines, pumps or pumping installations characterised by varying the volume of the working chamber
    • F04C14/185—Control of, monitoring of, or safety arrangements for, machines, pumps or pumping installations characterised by varying the volume of the working chamber by varying the useful pumping length of the cooperating members in the axial direction
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01M—LUBRICATING OF MACHINES OR ENGINES IN GENERAL; LUBRICATING INTERNAL COMBUSTION ENGINES; CRANKCASE VENTILATING
    • F01M1/00—Pressure lubrication
    • F01M1/16—Controlling lubricant pressure or quantity
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01P—COOLING OF MACHINES OR ENGINES IN GENERAL; COOLING OF INTERNAL-COMBUSTION ENGINES
    • F01P5/00—Pumping cooling-air or liquid coolants
    • F01P5/10—Pumping liquid coolant; Arrangements of coolant pumps
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16N—LUBRICATING
    • F16N13/00—Lubricating-pumps
    • F16N13/20—Rotary pumps
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01P—COOLING OF MACHINES OR ENGINES IN GENERAL; COOLING OF INTERNAL-COMBUSTION ENGINES
    • F01P3/00—Liquid cooling
    • F01P2003/006—Liquid cooling the liquid being oil
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B3/00—Engines characterised by air compression and subsequent fuel addition
    • F02B3/06—Engines characterised by air compression and subsequent fuel addition with compression ignition
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C2/00—Rotary-piston machines or pumps
    • F04C2/08—Rotary-piston machines or pumps of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing
    • F04C2/12—Rotary-piston machines or pumps of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing of other than internal-axis type
    • F04C2/14—Rotary-piston machines or pumps of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing of other than internal-axis type with toothed rotary pistons
    • F04C2/18—Rotary-piston machines or pumps of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing of other than internal-axis type with toothed rotary pistons with similar tooth forms

Definitions

  • the present invention relates to a water-cooled diesel engine oil system according to the preamble of claim 1.
  • the diesel engine In heavy goods vehicle applications, conventional diesel engines operate between 500 rpm and 2500 rpm.
  • the diesel engine incorporates an oil pump which is typically dimensioned to provide about 1.25 bar pressure at 500 rpm when the oil is warm. Since the lubricating circuit, or oil gallery, through which the lubricating oil is fed imparts a throttling effect, the pressure at 1000 rpm rises to about 5 bar. A pressure of 5 bar is generally considered to be optimal for engine speeds of 1000 rpm and over. Accordingly, in a conventional lubricating system the oil pump is dimensioned to provide a flow of about 80 litres/min at 1000 rpm. This implies, however, that at 2000 rpm, the oil flow is twice that which is required. To cope with this overpressure, the lubricating circuit is provided with a pressure relief valve which is set to open at pressures above 5 bar. Thus, at 2000 rpm, half the energy consumed by the oil pump is dissipated through the pressure relief valve.
  • a portion of the excess oil flow which arises above 1000 rpm can be used for piston cooling. Accordingly, as the pressure in the lubricating oil exceeds 5 bar, i.e. at engine speeds above 1000 rpm, a valve is arranged to open to allow oil to flow into a cooling oil circuit. Due to the design of nozzles which direct the cooling oil towards the pistons, a suitable operating pressure in the cooling oil circuit is 1.25 bar with a flow rate of about 40 litres/min. This implies that at 2000 rpm, 75% of the energy of the oil which is available for the cooling oil circuit must be throttled away to ensure that the pressure in the cooling oil circuit does not exceed 1.25 bar.
  • One possible way of reducing the losses which up until now have arisen in the oil system of diesel engines is to connect two pumps for the lubricating oil circuit in parallel at low engine speeds. As the engine speed increases, a valve arrangement separates the output of the pumps into two circuits having different pressure levels, one for the lubricating oil and one for the cooling oil. In this manner, the criterion of high oil pressure at low engine speeds is attained at the same time that energy is saved at higher engine speeds.
  • FIG. 1 is a schematic representation of an internal combustion engine according to the invention having a lubricating oil circuit and a cooling, oil circuit;
  • Fig. 2 is a sectional view through a variable displacement pump which may be used in the engine according to the present invention
  • Fig. 3 is a sectional view along line III-III of Fig. 2;
  • Fig. 4 is a sectional view along line IV-IV of Fig. 2, and
  • Fig. 5 is a sectional view along line V-V of Fig. 2.
  • a water-cooled diesel engine for use in heavy goods vehicles is schematically depicted and denoted by reference numeral 1.
  • the engine includes a sump 2 from which oil is drawn via a conduit 3 to a pump unit 10.
  • the pump unit 10 comprises a pair of pumps which may be housed in a common housing 12.
  • the housing is provided with an inlet 14 and a pair of outlets 16.
  • One outlet from the pump unit 10 is arranged to feed oil to a lubricating oil circuit A, whilst the second outlet feeds oil to a cooling oil circuit B.
  • oil which is intended for the lubricating oil circuit A should, at operating temperature, be pressurized to about 5 bar, whilst oil for the cooling oil circuit B should have a pressure of about 1.25 bar. It is generally desirable that these pressures be attained at 1000 rpm and that the pump unit be so dimensioned that, at this engine speed, about 80 litres/min of oil be pumped to the lubricating oil circuit A and about 40 litres/min of oil be pumped to the cooling oil circuit B.
  • the pair of pumps comprised in the pump unit 10 are variable displacement pumps so that the pressure and flow rates which are achieved at 1 000 rpm are substantially maintained at engine speeds above 1 000 rpm.
  • variable displacement pump any type of variable displacement pump may be incorporated in the pump unit, such as sliding vane pumps in which the rotor chamber is arranged to be displaceable with respect to the rotor to thereby vary the volume of the pumping chambers.
  • Rotor pumps are also known in which the ports are positioned relative to the offset of the rotors such that they are uniquely associated with increasing volume between rotors on the inlet side and decreasing volume on the outlet. By rotating the offset, the ports are associated with a volume which is both increasing in part of its rotation and decreasing before passing on to the next port. By altering the phase difference between the sets of rotors, flows between zero and full output are possible.
  • variable displacement pump which is illustrated in Figs. 2 to 5.
  • Such a type of pump is claimed per se in a co-pending application in the name of the present applicant.
  • a driving gearwheel assembly 18 is arranged for rotation about a first longitudinal axis 20 centrally located within the housing 12.
  • the driving gearwheel assembly may be caused to rotate in any known manner such as via a power take-off from the camshaft or crankshaft of an engine.
  • the pump 10 further comprises a pair of driven gearwheel assemblies 22 which are arranged to intermesh with the driving gearwheel assembly 18, with the driven gearwheel assemblies being arranged for rotation about second longitudinal axes 24 within the housing.
  • the driven gearwheel assemblies are arranged on either side of the driving gearwheel assembly 18, with all three assemblies lying parallel to each other.
  • the gearwheel assemblies may advantageously be made from sintered steel.
  • the driving gearwheel assembly 18 and the driven gearwheel assembly 22 or assemblies are arranged to effect relative axial displacement along either or both longitudinal axes 20, 24.
  • the driving gearwheel assembly 18 is axially stationary in the housing 12, whilst each driven gearwheel assembly 22 is independently axially displaceable along its associated longitudinal axis. How the axial displacement is attained will become apparent from the following description.
  • the driving gearwheel assembly generally comprises a gearwheel portion 26 extending from a smooth cylindrical portion 28.
  • the gearwheel portion 26 is adapted to engage and mesh with a corresponding gearwheel 30 on each driven gearwheel assembly 22.
  • the gearwheel 30 is journalled to a rotationally fixed, generally cylindrical guide block 32 whose shape is most clearly shown in Fig. 5.
  • the guide block of each driven gearwheel assembly is provided with a longitudinally extending arcuate recess 34 having a radius of curvature corresponding substantially to the diameter of the smooth cylindrical portion 28 of the driving gearwheel assembly. In this manner, the driven gearwheel assembly is able to effect an axial displacement along its axis without the guide block 32 fouling the cylindrical portion 28 of the driving gearwheel assembly.
  • each driven gearwheel assembly 22 delimits a respective first chamber 38 within the housing 12.
  • a second axial end 40 of each driven gearwheel assembly delimits a respective second chamber 42 within the housing.
  • the first chambers 38 are provided with force applying means which act on the first axial ends of the driven gearwheel assemblies 22.
  • These force applying means may be in the form of a resilient spring, or the chambers may be connected to a hydraulic or pneumatic source so that the pressures in the first chambers can be altered independently.
  • the driven gearwheel assembly will tend to be displaced to the left as shown in Fig. 2.
  • a feedback conduit 44 is provided from a point downstream of the fluid outlet 16 to the second chamber 42 of each driven gearwheel assembly 22. In this manner, if the pressure in the fluid outlet should rise, a corresponding increase in pressure in the second chamber 42 takes place, thereby causing the driven gearwheel assembly to shift to the right as shown in Fig. 2. Since a movement to the right reduces the area of intermesh between the gearwheel portion 26 of the driving gearwheel assembly 18 and the gearwheel 30 of the driven gearwheel assembly, a reduction of the outlet flow will occur, thereby creating a reduction in pressure.
  • force applying means for the first chambers 38 are selected such that the extent of overlap between the driving gearwheel assembly 18 and the driven gearwheel assemblies at 1000 rpm results in an outlet pressure of 5 bar in the lubricating oil circuit A and an outlet pressure of 1.25 bar in the cooling oil circuit B.
  • an increase in the outlet pressures will cause the driven gearwheel assemblies to be displaced to the right as shown in Fig. 1 due to the increase in pressure in the second chambers 42. Since a displacement to the right reduces the extent of overlap between the driving and the driven gearwheel assemblies, a corresponding reduction in the outlet pressures will be attained.

Abstract

A water-cooled diesel engine oil system is described, having a lubricating oil circuit (A) and a cooling oil circuit (B). To minimize the energy required to circulate the oil in the circuits, a lubricating oil pump is included in the lubricating oil circuit and a cooling oil pump is included in the cooling oil circuit, with both pumps (10) being variable displacement pumps.

Description

TITLE: Water-Cooled Diesel Engine Oil System
TECHNICAL FIELD:
The present invention relates to a water-cooled diesel engine oil system according to the preamble of claim 1.
BACKGROUND OF THE INVENTION:
In heavy goods vehicle applications, conventional diesel engines operate between 500 rpm and 2500 rpm. For lubrication purposes, the diesel engine incorporates an oil pump which is typically dimensioned to provide about 1.25 bar pressure at 500 rpm when the oil is warm. Since the lubricating circuit, or oil gallery, through which the lubricating oil is fed imparts a throttling effect, the pressure at 1000 rpm rises to about 5 bar. A pressure of 5 bar is generally considered to be optimal for engine speeds of 1000 rpm and over. Accordingly, in a conventional lubricating system the oil pump is dimensioned to provide a flow of about 80 litres/min at 1000 rpm. This implies, however, that at 2000 rpm, the oil flow is twice that which is required. To cope with this overpressure, the lubricating circuit is provided with a pressure relief valve which is set to open at pressures above 5 bar. Thus, at 2000 rpm, half the energy consumed by the oil pump is dissipated through the pressure relief valve.
In a known system, a portion of the excess oil flow which arises above 1000 rpm can be used for piston cooling. Accordingly, as the pressure in the lubricating oil exceeds 5 bar, i.e. at engine speeds above 1000 rpm, a valve is arranged to open to allow oil to flow into a cooling oil circuit. Due to the design of nozzles which direct the cooling oil towards the pistons, a suitable operating pressure in the cooling oil circuit is 1.25 bar with a flow rate of about 40 litres/min. This implies that at 2000 rpm, 75% of the energy of the oil which is available for the cooling oil circuit must be throttled away to ensure that the pressure in the cooling oil circuit does not exceed 1.25 bar.
If the oil has not reached its normal operating temperature, its viscosity is much greater and the pressure increases to its desired level at a correspondingly lower engine speed. In other words, an even greater portion of the energy demanded by the oil pump is lost through the pressure limiting valve.
From US-A-4 449 487 it is known to provide an air-cooled internal combustion engine with a lubricating oil circuit and a cooling oil circuit. However, because the engine in said patent does not rely on water-cooling, a substantial flow of cooling oil is required. Accordingly, in said patent two oil pumps are provided, i.e. a relatively high pressure pump for the lubricating oil circuit and a relatively low pressure, high through-flow pump for the cooling oil circuit.
If the twin pump arrangement of US-A-4 449 487 were to be incorporated in the diesel engine described above, the energy losses would be even higher than those already mentioned because not only would the lubricating oil pump require a pressure relief valve to open above 1000 rpm, so too would the cooling oil circuit in order to maintain the cooling oil circuit pressure at 1.25 bar.
One possible way of reducing the losses which up until now have arisen in the oil system of diesel engines is to connect two pumps for the lubricating oil circuit in parallel at low engine speeds. As the engine speed increases, a valve arrangement separates the output of the pumps into two circuits having different pressure levels, one for the lubricating oil and one for the cooling oil. In this manner, the criterion of high oil pressure at low engine speeds is attained at the same time that energy is saved at higher engine speeds.
One disadvantage with the latter system is that the valve arrangement for separating the output of the pumps is relatively complicated.
SUMMARY OF THE INVENTION:
It is therefore an object of the present invention to provide a water-cooled diesel engine oil system in which losses are minimized, without recourse to complicated valve arrangements.
This is achieved according to the present invention by an internal combustion engine according to claim 1.
Since, in the present invention, separate lubricating and cooling oil pumps are provided and these pumps have variable displacements, it is assured that the pumps supply only the required quantity of oil at any given engine speed. This implies that only that energy which is required to provide the desired flows is demanded by the pumps. In addition, no throttle valves or overpressure valves are required.
Preferred embodiments of the present invention are detailed in the dependent claims.
BRIEF DESCRIPTION OF THE DRAWINGS:
The invention will be described in the following in greater detail by way of example only and with reference to the attached drawings, in which Fig. 1 is a schematic representation of an internal combustion engine according to the invention having a lubricating oil circuit and a cooling, oil circuit;
Fig. 2 is a sectional view through a variable displacement pump which may be used in the engine according to the present invention;
Fig. 3 is a sectional view along line III-III of Fig. 2;
Fig. 4 is a sectional view along line IV-IV of Fig. 2, and
Fig. 5 is a sectional view along line V-V of Fig. 2.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS: In Fig. 1, a water-cooled diesel engine for use in heavy goods vehicles is schematically depicted and denoted by reference numeral 1. The engine includes a sump 2 from which oil is drawn via a conduit 3 to a pump unit 10. The pump unit 10 comprises a pair of pumps which may be housed in a common housing 12. The housing is provided with an inlet 14 and a pair of outlets 16. One outlet from the pump unit 10 is arranged to feed oil to a lubricating oil circuit A, whilst the second outlet feeds oil to a cooling oil circuit B.
Typically, oil which is intended for the lubricating oil circuit A should, at operating temperature, be pressurized to about 5 bar, whilst oil for the cooling oil circuit B should have a pressure of about 1.25 bar. It is generally desirable that these pressures be attained at 1000 rpm and that the pump unit be so dimensioned that, at this engine speed, about 80 litres/min of oil be pumped to the lubricating oil circuit A and about 40 litres/min of oil be pumped to the cooling oil circuit B. In accordance with the present invention, the pair of pumps comprised in the pump unit 10 are variable displacement pumps so that the pressure and flow rates which are achieved at 1 000 rpm are substantially maintained at engine speeds above 1 000 rpm.
In principle, any type of variable displacement pump may be incorporated in the pump unit, such as sliding vane pumps in which the rotor chamber is arranged to be displaceable with respect to the rotor to thereby vary the volume of the pumping chambers. Rotor pumps are also known in which the ports are positioned relative to the offset of the rotors such that they are uniquely associated with increasing volume between rotors on the inlet side and decreasing volume on the outlet. By rotating the offset, the ports are associated with a volume which is both increasing in part of its rotation and decreasing before passing on to the next port. By altering the phase difference between the sets of rotors, flows between zero and full output are possible.
However, and in accordance with a further aspect of the present invention, it is advantageous to use the type of variable displacement pump which is illustrated in Figs. 2 to 5. Such a type of pump is claimed per se in a co-pending application in the name of the present applicant.
Accordingly, and with reference to Fig. 2, a driving gearwheel assembly 18 is arranged for rotation about a first longitudinal axis 20 centrally located within the housing 12. The driving gearwheel assembly may be caused to rotate in any known manner such as via a power take-off from the camshaft or crankshaft of an engine.
The pump 10 further comprises a pair of driven gearwheel assemblies 22 which are arranged to intermesh with the driving gearwheel assembly 18, with the driven gearwheel assemblies being arranged for rotation about second longitudinal axes 24 within the housing. As is apparent from the drawings, in a preferred embodiment of the invention, the driven gearwheel assemblies are arranged on either side of the driving gearwheel assembly 18, with all three assemblies lying parallel to each other. Depending on the chosen field of use, the gearwheel assemblies may advantageously be made from sintered steel.
The driving gearwheel assembly 18 and the driven gearwheel assembly 22 or assemblies are arranged to effect relative axial displacement along either or both longitudinal axes 20, 24. In the illustrated embodiment, the driving gearwheel assembly 18 is axially stationary in the housing 12, whilst each driven gearwheel assembly 22 is independently axially displaceable along its associated longitudinal axis. How the axial displacement is attained will become apparent from the following description.
The driving gearwheel assembly generally comprises a gearwheel portion 26 extending from a smooth cylindrical portion 28. The gearwheel portion 26 is adapted to engage and mesh with a corresponding gearwheel 30 on each driven gearwheel assembly 22. The gearwheel 30 is journalled to a rotationally fixed, generally cylindrical guide block 32 whose shape is most clearly shown in Fig. 5. Thus, the guide block of each driven gearwheel assembly is provided with a longitudinally extending arcuate recess 34 having a radius of curvature corresponding substantially to the diameter of the smooth cylindrical portion 28 of the driving gearwheel assembly. In this manner, the driven gearwheel assembly is able to effect an axial displacement along its axis without the guide block 32 fouling the cylindrical portion 28 of the driving gearwheel assembly. Since, in the present invention, it is desired to have a constant pressure pump, the pump unit is provided with automatic feedback to maintain constant pressure substantially independently of the speed of rotation of the driving gearwheel assembly. In order to achieve this, a first axial end 36 of each driven gearwheel assembly 22 delimits a respective first chamber 38 within the housing 12. Similarly, a second axial end 40 of each driven gearwheel assembly delimits a respective second chamber 42 within the housing.
In order to cause the driven gearwheel assemblies to effect an axial displacement, the first chambers 38 are provided with force applying means which act on the first axial ends of the driven gearwheel assemblies 22. These force applying means may be in the form of a resilient spring, or the chambers may be connected to a hydraulic or pneumatic source so that the pressures in the first chambers can be altered independently. As soon as the force acting on the first axial end of the driven gearwheel assembly is greater than the force applied to the second axial end, the driven gearwheel assembly will tend to be displaced to the left as shown in Fig. 2.
So as to ensure that the pump automatically adapts itself to changes in the rotational speed of the driving gearwheel assembly 18, a feedback conduit 44 is provided from a point downstream of the fluid outlet 16 to the second chamber 42 of each driven gearwheel assembly 22. In this manner, if the pressure in the fluid outlet should rise, a corresponding increase in pressure in the second chamber 42 takes place, thereby causing the driven gearwheel assembly to shift to the right as shown in Fig. 2. Since a movement to the right reduces the area of intermesh between the gearwheel portion 26 of the driving gearwheel assembly 18 and the gearwheel 30 of the driven gearwheel assembly, a reduction of the outlet flow will occur, thereby creating a reduction in pressure.
It will be apparent from the above that the actual outlet pressure in each outlet will be dependent on the area of intermesh between the gearwheels of the driving and respective driven gearwheel assemblies. The area of intermesh is primarily determined by the extent of overlap of these gearwheels. Since the extent of overlap is dependent on the force acting on the first axial end 36 of the driven gearwheel assembly, the desired output pressure can be achieved by suitable selection of the force exerted by the force applying means within the first chamber 38. Since two driven gearwheel assemblies are provided, the outlet pressure from each assembly can be independently determined by selecting a suitable force for the force applying means in the respective first chamber 38.
When incorporated in the system according to the present invention, the above-described pump operates in the following manner.
With particular reference to Figs. 1 and 2, force applying means for the first chambers 38 are selected such that the extent of overlap between the driving gearwheel assembly 18 and the driven gearwheel assemblies at 1000 rpm results in an outlet pressure of 5 bar in the lubricating oil circuit A and an outlet pressure of 1.25 bar in the cooling oil circuit B. As the engine speed increases above 1 000 rpm, an increase in the outlet pressures will cause the driven gearwheel assemblies to be displaced to the right as shown in Fig. 1 due to the increase in pressure in the second chambers 42. Since a displacement to the right reduces the extent of overlap between the driving and the driven gearwheel assemblies, a corresponding reduction in the outlet pressures will be attained. From the above, it will be apparent that the utilization of this type of pump as an oil pump in a water-cooled diesel engine oil system will result in considerable energy savings since the pump only produces the volume flow rate which is actually required. In conventional pumps, the additional flow which was generated over 1 000 rpm was redundant and the surplus pressure was removed from the oil circuit via a pressure release valve. Due to the self- adjusting nature of the pump used in the system according to the present invention, no pressure release valve is necessary.
The invention is not restricted to the embodiments described above and shown in the drawings but may be varied within the scope of the appended claims. For example, it will be apparent to the skilled person that the diameters of the driving and driven gearwheel assemblies need not be identical. In addition, the gearwheel assemblies do not need to be located in one and the same plane. Furthermore, the force applying means present in the first chamber 38 may be partially or totally replaced by mechanical tensioning means located within the second chamber 42.

Claims

What is claimed is:
1. A water-cooled diesel engine oil system, comprising a lubricating oil circuit; a lubricating oil pump in said lubricating oil circuit for supplying said lubricating oil circuit with oil, and a cooling oil circuit; characterized in that a cooling oil pump is provided in said cooling oil circuit for supplying said cooling oil circuit with oil, and in that said lubricating oil pump and said cooling oil pump are variable displacement pumps.
2. The system according to claim 1, characterized in that said pumps are housed in a common housing.
3. The system according to claim 1 or 2, characterized in that said pumps are gearwheel pumps.
4. The system according to claim 3, characterized in that said housing houses a driving gearwheel assembly which intermeshes with two driven gearwheel assemblies, said driving gearwheel assembly (18) being arranged for rotation about a first longitudinal axis (20) within said housing, and said driven gearwheel assemblies (22) being arranged for rotation about a second longitudinal axis (24) within said housing, said first and second longitudinal axes being substantially parallel, and in that said driving gearwheel assembly (18) and said driven gearwheel assemblies (22) are arranged to effect relative axial displacement along said longitudinal axes (20, 24).
5. The system according to claim 4, characterized in that said driving gearwheel assembly (18) is axially stationary in said housing (12) and in that said driven gearwheel assemblies (22) are independently axially displaceable along their associated longitudinal axes (24).
6. The system according to claim 5, characterized in that a first axial end (36) of each driven gearwheel assembly (22) delimits a first chamber (38) within said housing (12), and a second axial end (40) of each driven gearwheel assembly delimits a second chamber (42) within said housing.
7. The system according to claim 6, characterized in that force applying means are provided within each said first chamber (38), which means act on said first axial end (36) of each respective driven gearwheel assembly (22) to create a pressure difference across said axial ends (36; 40) to thereby effect said axial displacement.
8. The system according to claim 7, characterized in that the extent of axial displacement of each driven gearwheel assembly (22) is determined by the pressure difference prevailing over said axial ends (36; 40) of said respective driven gearwheel assembly.
9. The system according to claim 8, characterized in that each driven gearwheel assembly (22) cooperates with a respective fluid outlet (16) in said housing (12), and in that said second chamber (42) of each driven gearwheel
* assembly cooperates with a point downstream of said fluid outlet via a feedback conduit (44).
10. The system according to claim 8 or 9, characterized in that said force applying means within one first chamber (38) applies a greater force than the force applying means within the other first chamber.
PCT/SE1996/000435 1995-04-13 1996-04-03 Water-cooled diesel engine oil system WO1996032570A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SE9501381A SE9501381L (en) 1995-04-13 1995-04-13 Oil system for a water-cooled diesel engine
SE9501381-9 1995-04-13

Publications (1)

Publication Number Publication Date
WO1996032570A1 true WO1996032570A1 (en) 1996-10-17

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WO (1) WO1996032570A1 (en)

Cited By (6)

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Publication number Priority date Publication date Assignee Title
DE19926350C1 (en) * 1999-06-10 2000-11-02 Daimler Chrysler Ag Oil supply system for IC engine uses single pump with separate pump feed chambers for supplying engine lubrication points and piston sprays for cooling pistons
US6763797B1 (en) * 2003-01-24 2004-07-20 General Motors Corporation Engine oil system with variable displacement pump
DE102006037461A1 (en) * 2006-08-10 2008-02-14 Bayerische Motoren Werke Ag Operation of variable-delivery oil-lubrication pump of diesel engine, employs pressure-regulated bypass with temperature-controlled pumping modes
DE102007002677A1 (en) * 2007-01-18 2008-07-24 Bayerische Motoren Werke Aktiengesellschaft Method for actuating flow rate adjustable lubricant pump in lubricant closed loop of diesel engine, involves determining pre-determined flow rate depending on number of rotations of diesel engine and fuel amount is assigned to diesel engine
WO2008089714A1 (en) * 2007-01-27 2008-07-31 Geräte- und Pumpenbau GmbH Dr. Eugen Schmidt Adjustable coolant pump
DE102013001750A1 (en) * 2013-01-31 2014-07-31 Volkswagen Aktiengesellschaft Method for controlling oil pressure for combustion engine, involves keeping oil pressure in first speed range of engine constant and increasing oil pressure in second speed range with increasing speed so as to be above first speed range

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US4449487A (en) * 1980-11-27 1984-05-22 Volkswagenwerk Ag Internal-combustion engine having lubricating and cooling oil circuits
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Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19926350C1 (en) * 1999-06-10 2000-11-02 Daimler Chrysler Ag Oil supply system for IC engine uses single pump with separate pump feed chambers for supplying engine lubrication points and piston sprays for cooling pistons
US6763797B1 (en) * 2003-01-24 2004-07-20 General Motors Corporation Engine oil system with variable displacement pump
DE102006037461A1 (en) * 2006-08-10 2008-02-14 Bayerische Motoren Werke Ag Operation of variable-delivery oil-lubrication pump of diesel engine, employs pressure-regulated bypass with temperature-controlled pumping modes
DE102007002677A1 (en) * 2007-01-18 2008-07-24 Bayerische Motoren Werke Aktiengesellschaft Method for actuating flow rate adjustable lubricant pump in lubricant closed loop of diesel engine, involves determining pre-determined flow rate depending on number of rotations of diesel engine and fuel amount is assigned to diesel engine
WO2008089714A1 (en) * 2007-01-27 2008-07-31 Geräte- und Pumpenbau GmbH Dr. Eugen Schmidt Adjustable coolant pump
DE102013001750A1 (en) * 2013-01-31 2014-07-31 Volkswagen Aktiengesellschaft Method for controlling oil pressure for combustion engine, involves keeping oil pressure in first speed range of engine constant and increasing oil pressure in second speed range with increasing speed so as to be above first speed range

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SE9501381L (en) 1996-10-14

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