GB2466446A

GB2466446A - I.c. engine oil supply system with insulated oil storage for improved cold start efficiency

Info

Publication number: GB2466446A
Application number: GB0823101A
Authority: GB
Inventors: Volker Drunert
Original assignee: GM Global Technology Operations LLC
Current assignee: GM Global Technology Operations LLC
Priority date: 2008-12-18
Filing date: 2008-12-18
Publication date: 2010-06-23
Also published as: GB0823101D0

Abstract

An oil supply system 10 for supplying a combustion engine 12 of a vehicle with motor oil 20 comprises oil storage 18, eg an oil pan 14 with oil sump 16, for providing motor oil 20 to the engine and a thermally insulated oil storage container 32 having greater heat insulation than the oil storage 18. The insulated storage container 32 is adapted to be permanently fed, eg by pump 22, during operation of the combustion engine 12. There may be no valve(s) between the oil storage 18 and the insulated storage container 32. The insulated storage container 32 may have sensor(s) 38 to detect parameters of the oil, eg level and temperature, which are sent to a control unit 40 which controls the pump 22. After a cold start the combustion engine 12 may be fed with heated motor oil from the heat insulated storage container 32 to improve cold start efficiency over the life time of the engine without the need for additional equipment.

Description

Oil supply and method for operating a combustion engine

Description

The invention relates to an oil supply for supplying an internal combustion engine of a vehicle with motor oil as well as to a method for operating a combustion engine of a vehicle by means of an oil supply.

Internal combustion engines have an optimum operating temperature with respect to efficiency, emissions, wear and others. When after a longer time without operation a cold combustion engine is started ("cold start") the efficiency of the combustion engine is poor in comparison to the efficiency of the combustion engine at operating temperature.

It is the object of the invention to provide an oil supply as well as a method of operating a combustion engine, by means of which an improved cold start efficiency over the life time of the combustion engine is provided which particularly improves cold start efficiency without the need for additional aggregates.

The solution of the object is achieved by an oil supply comprising the features of claim 1 as well as by a method of operating a combustion engine comprising the features of claim 13. Preferred embodiments are given by the dependent claims.

The oil supply according to the invention for supplying a combustion engine of a vehicle with motor oil comprises an oil storage for providing motor oil, for instance a sump of an oil pan of the combustion engine.

According to the invention a thermally insulated storage container is provided for storing heated motor oil, wherein the storage container comprises a greater heat insulation than the oil storage. The storage container is adapted to be permanently fed during operation of the combustion engine.

Since the oil storage is not heat insulated a sufficient cooling of the motor oil during normal operation conditions is ensured. Due to the heat insulated storage container heated motor oil can be stored during and/or after operation of the combustion engine and kept at a higher temperature than the other motor oil over a long period of time. By means of the heat insulated storage container even after a longer time of for example one or two days relatively hot oil can be supplied to the engine immediately after cold start.

Further it is possible to mix the warm motor oil from the storage container with the cold motor oil of the oil storage providing an increased overall temperature of the motor oil at once after the start of the combustion engine. Due to the lower viscosity of the warmer engine oil from the insulated storage, friction of the engine after cold start is greatly reduced which leads to lower fuel consumption and CO2 emissions. Since the storage container is adapted to be permanently fed during operation of the combustion engine, it is possible to arrange the storage container in line with an existing oil duct system without the need for additional aggregates like valves and/or pumps for filling and emptying the storage container. It is sufficient to provide an additional heat insulated storage volume.

Particularly the heated motor oil stored by the storage container comprises a temperature T and the motor oil stored by the oil storage comprises a temperature T, wherein it is T �= Ts, particularly after a stop and/or before a start of the combustion engine.

Ideally, the insulated storage container should be filled with as hot as possible engine oil. Typically, engine oil is pumped through the insulated storage container during operation of the combustion engine. However, in case actual engine oil temperature gets significantly hotter than normal operating temperature, it may be preferred to fill and trap engine oil before the engine is switched off. Is

Preferably the oil storage and the insulated oil container are valve-free connected. This means when pumping oil from the oil storage the insulated oil container is automatically filled during operation of the combustion engine. It is safeguarded that the insulated oil container is filled with oil of the hottest actual temperature. At cold start, the combustion engine is fed with oil from the insulated container first, so that cold oil from the oil storage can be mixed with the present hot oil of the oil container before the mixed oil is led to the combustion engine. The risk, that at a cold start very cold oil is fed to the combustion engine, is reduced. If so, by means of check valves or other devices it is safeguarded that the heated motor oil does not flow out of the insulated oil container when the combustion engine is switched off.

Particularly an oil pump for feeding the combustion engine from the oil storage is provided, wherein the storage container is fed by means of an oil pressure provided mainly by the oil pump. A second oil pump for feeding and/or emptying the storage container is not necessary.

In a preferred embodiment an oil pan for connecting to a motor block of the combustion engine is provided, wherein the oil pan comprises an oil sump, which comprises the oil storage. Particularly the oil pan comprises the storage container. The storage container may be a separated heat insulated compartment of the oil pan. This facilitates to provide an existing combustion engine design with the heat insulated storage container.

Further the storage container may be easily press fitted into the oil sump of the oil pan.

Particularly the insulated storage container may comprise one first opening for filling only and one second opening for emptying only. Thus, only two openings are provided, so that the insulated storage container can be permanently flowed through during operation. This further leads to good heat insulation since a perforation of a provided heat insulation layer is reduced to a minimum.

Particularly the storage container may comprise a heater for heating motor oil inside the storage container. Even after a long period of non-operation of the combustion engine it is possible to provide preheated motor oil by means of the heater for the cold start.

Further is possible to prevent a too low temperature of the motor oil inside the storage container.

Particularly an oil duct connected to the oil storage for supplying motor oil from the oil storage to the combustion engine and a return duct connected to the oil storage for leading motor oil from the combustion engine to the oil storage are provided, wherein the oil storage and/or the oil duct and/or the return duct comprises the storage container. Particularly the return duct may comprise engine parts to be lubricated. Thus, the insulated storage container may be connected for filling and/or emptying with the ducts of an engine oil loop, which is present for the normal operation mode of the combustion engines. The building space is not significantly affected.

The invention further relates to a method for operating a combustion engine of a vehicle, particularly by means of an oil supply, which may be designed as previously described. According to the invention during operation of the combustion engine a heat insulated storage container is permanently fed with heated motor oil coming from the combustion engine and the combustion engine is fed from the insulated storage container with motor oil directly on or after the start of the combustion engine.

By means of the heat insulated storage container even after a longer time of non-operation of for example one or two days heated motor oil is present at once without the need to heat the motor oil prior. After the cold start the combustion engine may be fed with heated motor oil from the heat insulated storage container, which is replaced by motor oil from the oil sump, without the need for additional aggregates. Thus, an improved cold start efficiency over the life time of the combustion engine is provided, which leads in turn to a C02-reduction of the combustion engine.

These and other aspects of the invention will be apparent from and elucidated with reference to a preferred embodiment described hereinafter.

In the drawings: Fig. 1 is a schematic conceptual view of an oil supply according to the invention.

The oil supply 10 for feeding a combustion engine 12 comprises an oil pan 14. The oil pan 14 is part of the combustion engine 12 and comprises an oil surnp 16, which provides an oil storage 18 for motor oil 20. By means of an oil pump 22 the motor oil 20 of the oil storage 18 may be supplied via an oil duct 24 to certain parts 26 of the combustion engine 12 for lubrication. From the parts 26 the engine oil drips to the oil storage 18 of the oil sump 16. Due to the oil duct 24 and the parts 26 of the return duct of the engine that get lubricated 26 an engine oil loop 28 is provided, which is closed via the oil storage 18 of the oil pan 14.

By means of the oil pump 22 hot motor oil 20 from the oil surnp 16 or any other appropriate part of the engine 12 may be led trough only one first opening 30 to a storage container 32, which is thermally insulated by a thermal insulating layer 34. Via only one second opening 36 the hot motor oil 20 may be emptied from the storage container 32. For feeding the combustion engine 12 at a cold start with motor oil of a higher temperature the oil pump 22 pumps the warm motor oil from the heat insulated storage container 32 downstream the oil duct 24 of the engine oil loop 28, so that the combustion engine 12 is fed with warm motor oil. In this embodiment a single oil pump 22 is sufficient to fill and deplete the storage container 32 as well as the oil storage 18.

The storage container 32 may comprise one or more sensors 38, by means of which the level of the storage container 32 and/or the temperature and/or any other applicable parameter of the filled motor oil may be detected. This information is processed by a control unit for adjusting the oil pump 22, so that the combustion engine 12 may be operated by means of the oil pump 22 in an appropriate manner with respect to the actual oil temperature of the fed motor oil 20.