WO2014033469A2

WO2014033469A2 - Lubrication system

Info

Publication number: WO2014033469A2
Application number: PCT/GB2013/052283
Authority: WO
Inventors: Cedric Rouaud; David Greenwood
Original assignee: Ricardo Uk Ltd.
Priority date: 2012-08-30
Filing date: 2013-08-30
Publication date: 2014-03-06
Also published as: GB201215417D0; GB201315473D0; GB2508262A; WO2014033469A3

Abstract

A vehicle has an engine and a lubrication system for the engine. The lubrication system includes a lubricant reservoir for storing engine lubricant and an electrically-conductive heating element arranged for heating lubricant as it travels between the reservoir and the engine. The lubrication system further includes a conduit for conveying engine lubricant between said reservoir and the vehicle engine. The heating arrangement is configured for receiving electrical current to heat the heating element. The heating element is arranged in contact with an external surface of the conduit for heating of the conduit.

Description

Lubrication System

The present invention relates to a lubrication system for an engine, more particularly, but not exclusively, to a lubrication system for a vehicle combustion engine.

It is well known to use lubricant to lubricate moving parts of an engine, in order to reduce engine wear. It is also known to warm engine lubricant before starting an engine, in order to reduce fuel consumption during engine warm-up (e.g. by reducing viscosity and hence friction).

A number of heating arrangements for engines are known, such as block heaters, dipstick heaters and sump heaters (sometimes referred to as 'pan' heaters). A block heater is typically inserted into an engine block (e.g. in place of one of the engine's core plugs) and arranged to heat engine oil and/or coolant through the engine block. Dipstick heaters replace a standard oil dipstick, extending into a vehicle's oil sump to directly heat the oil held in the sump, whereas sump heaters are arranged to provide direct heating to a wall of the oil sump.

There are disadvantages with the above-listed heaters. Block heaters are inefficient, as heat is wasted on parts of the engine not requiring heating. Dipstick heaters are by their nature limited in diameter, so provide only a relatively limited heating capacity. Sump heaters heat all of the oil in the pan and so can take time to be effective. Moreover, each of these known arrangements require an external power source, which can be inconvenient and costly to incorporate.

There is a need for a heating arrangement for an engine lubrication system which addresses one or more of the above issues.

According to the present invention there is provided a lubrication system for an engine. The lubrication system comprises a lubricant reservoir for holding a body of engine lubricant, and a heating arrangement for heating engine lubricant within the system. The system further includes a conduit for conveying engine lubricant between said reservoir and a vehicle engine. The heating arrangement is configured to heat lubricant within the conduit.

This system allows for targeted heating of lubricant, making the system more efficient than known systems (i.e. those which heat the entire lubricant reservoir or engine block).

The heating arrangement may be configured to heat the conduit per se, e.g. using a heating element in conductive contact with the conduit. This arrangement avoids heating of unnecessary parts of the system or the engine.

The heating element may be a resistance wire, which may be helical, and/or may be configured to encircle the conduit. The heating element may comprise at least one portion not in contact with the conduit, and may further comprise insulation material configured to insulate said at least one portion.

The system may include a pump, wherein the conduit may extend between the reservoir and the pump, or may extend between the pump and said engine. The system therefore provides for heating of lubricant after it leaves the reservoir and before it arrives at the engine. There is further provided a vehicle engine including a lubrication system as described above. The system may be configured such that the heating arrangement receives power produced by regenerative braking of the vehicle, and/or from a vehicle battery. This arrangement is convenient, economical and efficient, removing as it does the need for an external power source of the kind required by the known heating arrangements referred to above.

There is yet further provided a vehicle having an engine, a lubrication system for the engine and a regenerative braking system. The vehicle is configured such that energy from the regenerative braking system is used to heat lubricant within the lubrication system. Again, this is efficient, economical and convenient. The lubrication system of the vehicle may be as described above. There is still further provided a vehicle having an engine and a lubrication system for the engine. The lubrication system includes a lubricant reservoir for storing engine lubricant. An electrically-conductive heating element is arranged for heating lubricant as it travels between the reservoir and the engine.

In exemplary embodiments, the lubrication system further includes a conduit for conveying engine lubricant between said reservoir and the vehicle engine. The heating arrangement is configured for receiving current to heat the heating element. Said heating element is arranged in contact with an external surface of the conduit for heating the conduit.

In exemplary embodiments, the heating element is a resistance wire.

In exemplary embodiments, the heating element is arranged in helical configuration to encircle the conduit.

In exemplary embodiments, the vehicle includes a power source for supplying electrical current to the heating element to heat the heating element, e.g. an alternator, battery or other capacitor, which may be connected to a regenerative braking system. In exemplary embodiments, the heating element comprises at least one portion not in contact with the conduit, and further comprising insulation material configured to insulate said at least one portion.

In exemplary embodiments, the vehicle includes an oil filter between the lubricant reservoir and the engine, and wherein said conduit is arranged between the reservoir and the oil filter, or between a pump for pumping engine lubricant within the system and the reservoir, or between said pump and the engine.

Other aspects and features of the invention will be apparent from the claims and following description of embodiments, made by way of example, with reference to the following drawings, in which: Figure 1 is a schematic view of a lubrication system according to a first embodiment of the invention; and Figure 2 is a schematic view of a lubrication system according to a second embodiment of the invention.

A vehicle engine is indicated generally at 10 in Figure 1. The engine 10 is an internal combustion engine and is provided with a lubrication system, indicated generally at 12, configured to provide lubricant to moving parts of the engine 10.

The lubrication system 12 includes a lubricant oil sump or reservoir 14 configured to contain lubricant 16. In this embodiment the lubricant 16 is a known engine oil, though other types of lubricant may be used in alternative embodiments.

The lubrication system 12 includes a pump 18 arranged to circulate oil about the system 12. When the pump 18 is in operation, oil is pumped from the reservoir 14 to the pump 18 through an oil pick-up pipe 15 and a first metal conduit 20. Oil 16 is then pumped to an oil filter 22 along a second metal conduit 24, before being dispensed to the engine 10 for lubrication. The system 12 forms a complete circuit, so that oil travels back to the reservoir 14 under gravity through a further series of conduits (not shown).

As previously described, it is advantageous to warm engine oil for reasons of fuel economy. The system 12 of this embodiment is configured such that oil is heated whilst in the first and/or second conduits 20, 24, i.e. after the oil has been pumped from the reservoir, yet before it is dispensed to the engine 10 for lubrication. In this way only the oil that is being pumped for imminent dispersal through the engine 10 is heated, rather than heat being used to warm stored oil in the reservoir 14.

Advantageously, heat is applied to the lubricant before it reaches the oil filter 22. For example, the conduits 20, 24 may be heated, so that oil passing therethrough is heated. In the embodiment of the invention shown in Figure 1, a heating arrangement 26 is configured to heat the first conduit 20. The heating arrangement 26 of this embodiment includes a heating element 28 in conductive contact with the first conduit 20, so that as the heating element 28 is heated, the metal conduit 20 is heated. The heating element 28 encircles the first conduit 20 so that an inner surface (not shown) of the heating element 28 is in contact with an outer surface 30 of the first conduit 20. The heating element is in this embodiment helical.

The heating element 28 is in this embodiment copper resistance wire, though in alternative embodiments other suitable conductive materials may be used. Importantly, the temperature of the wire 28 increases as the current through the wire 28 is increased. In exemplary embodiments, the diameter of the wire 28 is large enough to sustain a high current, but small enough to be wound about the conduit 20 to form a good conductive contact. In use, the heating element 28 is connected to a power supply (described below). The first conduit 20 is thus heated through conduction as the element 28 is heated, and the oil pumped therethrough is similarly heated by conduction. Heat is inhibited from escaping the heating element 28 by insulating material 32 arranged about the exposed surface of the heating element 28, improving efficiency. Once heated, oil is pumped through the second conduit 24 to the oil filter 22, before being dispersed into the engine 10 at a suitably high temperature.

In the second embodiment, shown in Figure 2, the heating arrangement 26 is used to heat the second conduit 24 rather than the first conduit 20. A heating element 28 similar to that of the first embodiment is arranged in conductive contact with the outer surface 30 of the second conduit 24. Again, the heating element 28 is helical, and encircles the second conduit 20. In use, when the heating element 28 is connected to a power supply (e.g. as described below) and has its temperature increased, the second conduit 24 is heated through conduction, such that oil pumped therethrough is also heated by conduction. Again, heat is inhibited from escaping the heating element 28 by insulating material 32 arranged about the exposed surface of the heating element 28. The heated oil is pumped to the oil filter 22 for dispersal into the engine 10 whilst warm. In these embodiments, the heating element 28 is configured to heat the oil to between 80°C and 120°C. Typically, the heating element 28 will require between 500W and 1.5kW to heat oil in the first or second conduit 20, 24 to this temperature - a significant reduction in the power that would be required to heat the amount of oil in the reservoir 14 to the same temperature.

In exemplary embodiments, oil temperature is measured by temperature sensors 36 positioned on the second conduit 24 and at a second point further around the system 12 (e.g. after passing through the engine but before re-entry to the reservoir 14). Temperature data collected by the sensors 36 is transmitted to an engine control unit 38, which monitors the oil temperature. The engine control unit 38 is configured to maintain the oil at a suitable temperature by regulation of power supplied to the heating element 28. If the oil temperature is lower than required, the engine control unit 38 increases the power to the heating element 28 so that the temperature of the heating element 28 is increased, thus increasing the temperature of the oil.

The engine control unit 38 monitors the oil when it is at ambient temperature, prior to starting of the engine 10, and adjusts power supply to the heating element 28 accordingly. For example, in cold climates, more power will be needed to heat the oil to a suitable starting temperature than will be required in temperate climates, and the engine control unit 38 ensures that adequate power is supplied for heating the oil prior to delivery to the engine (more particularly prior to delivery to the oil filter). The engine 10 is installed in a motor vehicle 40. The vehicle 40 of these embodiments includes a regenerative braking system 42 configured to generate power during vehicle braking. Generated power is stored in a vehicle battery 34 or other capacitor. Whilst regenerative braking is taking place, the heating element 28 is supplied with electricity from an alternator 44 via connections 35, rather than depleting the battery 34. When the oil is to be warmed prior to starting the engine 10, and when there is no regenerative braking, power for the heating element 28 is drawn from the battery 34. The battery 34 is recharged once the engine 10 is started. Recharging occurs through regenerative braking, where possible, to minimise fuel consumption.

Advantageously, the lubrication system allows only oil that is to be imminently used to be heated, improving efficiency over existing heaters (which typically heat the entire lubrication reservoir). Oil is heated through conduction rather than through direct contact with the heating element, removing the possibility of heated oil damaging the heating element. Heat is applied prior to delivery to the oil filter, providing further advantages. Oil is heated whilst being pumped in a stream through a conduit 20, 24, so low power is required to heat the oil to a suitable temperature. Oil temperature is monitored and controlled through the engine control unit, and can easily be varied through variation in power supply to the heating element. Power for heating is conveniently and economically drawn from the vehicle rather than from an external power source.

The system can be used in petroleum or diesel-fuelled cars, or in series or parallel hybrid electric vehicles, or in other suitable vehicles.

In alternative embodiments (not shown), both first and second conduits 20, 22 are heated.

In alternative embodiments (not shown), the conductive heating element may not be helical.

In alternative embodiments (not shown), other forms of suitable heating arrangements (e.g. not electrically-conductive) may be used for direct heating of the conduits 20, 24, or for heating the lubricant as it passes through one or both of the conduits 20, 24 or through other elements between the primary lubricant reservoir and the oil filter/engine.

Claims

1. A lubrication system for an engine, the lubrication system comprising a lubricant reservoir for holding a body of engine lubricant, and a heating arrangement for heating engine lubricant within the system, wherein the system further includes a conduit for conveying engine lubricant between said reservoir and a vehicle engine, and wherein the heating arrangement is configured to heat lubricant within the conduit.

2. A system according to claim 1 wherein the heating arrangement is configured to heat the conduit.

3. A system according to claim 2 wherein the heating arrangement comprises a heating element in conductive contact with the conduit.

4. A system according to claim 3 wherein the heating element is a resistance wire.

5. A system according to claim 4 wherein the wire is arranged in helical configuration to encircle the conduit.

6. A system according to any preceding claim wherein the heating arrangement comprises an electrically-conductive heating element.

7. A system according to claim 6 wherein the electrically-conductive heating element is in contact with the conduit for thermal-conductive heating of the conduit.

8. A system according to claim 6 or claim 7 including a power source for supplying electrical current to the heating element to heat the heating element.

9. A system according to any one of claims 3 to 8 wherein the heating element comprises at least one portion not in contact with the conduit, and further comprising insulation material configured to insulate said at least one portion.

10. A system according to any preceding claim including an oil filter between the lubricant reservoir and the engine, and wherein said conduit is arranged between the reservoir and the oil filter, or between a pump for pumping engine lubricant within the system and the reservoir, or between said pump and the engine.

11. A vehicle engine including a lubrication system according to any preceding claim.

12. An engine according to claim 11 wherein the system is configured such that the heating arrangement receives power produced by regenerative braking of the vehicle.

13. An engine according to claim 11 or claim 12 wherein the system is configured such that the heating arrangement receives power from a vehicle battery or vehicle alternator.

14. An engine according to any of claims 11 to 13 wherein temperature sensors are positioned within the lubrication system for transmitting temperature data to an engine control unit, for selective control of the heating arrangement.

15. A vehicle having an engine, a lubrication system for the engine and a regenerative braking system, wherein the lubrication system includes a heating element configured for receiving power from energy recovered under regenerative braking to heat lubricant within the lubrication system.

16. A vehicle according to claim 15 wherein the lubrication system includes a lubricant reservoir for storing engine lubricant, and the heating element is arranged for heating lubricant as it travels between the reservoir and the engine.

17. A vehicle according to claim 15 or claim 16 wherein temperature sensors are positioned within the lubrication system for transmitting temperature data to an engine control unit, for selective control of the heating element.

18. A vehicle according to any of claims 15 to 17 wherein the lubrication system is according to any one of claims 1 to 10.

19. A vehicle having an engine and a lubrication system for the engine, wherein the lubrication system includes a lubricant reservoir for storing engine lubricant and an electrically-conductive heating element arranged for heating lubricant as it travels between the reservoir and the engine.

20. A vehicle according to claim 19 wherein the lubrication system further includes a conduit for conveying engine lubricant between said reservoir and the vehicle engine, and wherein the heating arrangement is configured for receiving current to heat the heating element, and said heating element is arranged in contact with an external surface of the conduit for thermal-conductive heating of the conduit.