GB2252362A

GB2252362A - Engine fuel heating and oil filtration

Info

Publication number: GB2252362A
Application number: GB9123135A
Authority: GB
Inventors: Alan Robert Cook; Charles Vincent Maloney; George Seear
Original assignee: FUEL ECONOMY CORP Ltd
Current assignee: FUEL ECONOMY CORP Ltd
Priority date: 1991-02-01
Filing date: 1991-10-31
Publication date: 1992-08-05
Also published as: GB9123135D0

Abstract

Lubricating oil is passed through a container 1 containing an oil filter body 8 surrounded by a heat exchanger coil 13. Fuel is passed through the coil and is heated. A thermostat (34, Fig. 4) controls the mixing of heated fuel from the outlet 15 with unheated fuel to provide fuel at about 45 DEG C. <IMAGE>

Description

ENGINE FUEL HEATING AND OIL FILTRATION APPARATUS The invention relates to apparatus for use in heating fuel prior to its ignition in an engine, especially a Diesel engine or compression engine, and to the simultaneous filtration of the oil used to lubricate the engine.

It is known to pre-heat Diesel fuel prior its ignition into order to reduce fuel consumption. non apparatus or methods used are either unreliable or do not heat the fuel in a controlled wan.

For example, the heating devices affect the performance of engine by starving it of fuel from time to time or they are so inefficient that more than one heating means is required or ts are so uncontrolled that they cannot be used in hot climates. It is one object of the invention to provide reliable and efficient and controlled apparatus and method for the purpose specified.

Accordingly in one aspect the invention provides an engine fuel heating apparatus comprising a container having an inlet for the ingress of hot lubrication oil from the engine and an outlet for the egress of oil back to the engine, heat exchanger means located within the container and arranged, in use, to be substantially immersed within the hot oil flowing between the inlet and outlet of the container, the heat exchanger means having an inlet for the ingress of fuel from a reservoir thereof and an outlet for the egress of heated fuel to the engine, and being arranged to pass the fuel to the engine as demanded, a body of filter material being located within the container and arranged so that the oil flowing between the inlet and outlet passes through the body of filter material and is thereby filtered free of contaminants.

Apparatus of the invention can be provided as a single unit capable of simultaneously performing two different tasks.

In a more specific aspect, the invention provides a container having a compartment, the compartment having an open top and a closed floor, an oil filter element being contained within the compartment, an inlet being present in the floor of the container for the ingress of hot lubricating oil from an engine, an oil outlet comprising a pipe extending from a hole in the floor of the compartment to the outside of the container, elongate heat exchanger means comprising a length of tubing coiled about the compartment and including an inlet for the ingress of fuel from a reservoir thereof, and an outlet for the egress of fuel to the combustion chamber of the engine, the tubing being dimensioned so as not to substantially restrict the flow of fuel to the engine, whereby, in use, hot oil is passed into the inlet of the container through the filter element in the compartment and out through the oil outlet and fuel is passed along the heat exchanger from the inlet to the engine and the flowing fuel is continuously heated and the oil is continuously filtered.

Preferably the heat exchanger means comprises a coil or like length of tube. The diameter of the tube is selected so that the rate of flow of fuel to the engine is in excess of any engine demand requirements. The length of the tube is determined by the intended level of heating of the fuel and related factors.

The filter material may be a Nylon gauze or paper or a mixture.

Preferably the filter material comprises a microporous sheet of resin bonded cellulosic fibres derived from sulphated wood pulp; more specifically the filter material is a pulped mixture of sulphated hard wood and soft wood Rrafts. The fibres are split and then resin bonded to form sheets in which the majority of fibres ar oriented in one direction, the sheets are then dried and creped. Preferably the sheet has pores of 5 to 100 microns diameter.

The fuel and the oil may be arranged to flow in the same direction or in opposite directions.

It is a surprising feature of the invention that because the heating of the fuel is so efficient there is a serious risk that the fuel will be heated to a temperature above that at which the fuel will be harmed chemically, e.g. by degradation. According to another feature of the invention thermostat control means are present to reduce the temperature below a predetermined limit, typically about 450C in the case of Diesel fuel. Preferably such means are arranged to add relatively cold fuel from the fuel tank to the hot fuel in sufficient quantity to reduce the temperature as required.

In a much preferred Eeature, the apparatus as defined further includes thermostat means located in the main pipeline present between the container and the engine where the fuel is consumed, the thermostat including a temperature sensing device connected to a piston which at rest obstructs an inlet from an auxiliary pipeline connected to a supply of unheated fuel, the piston being arranged to reciprocate between two long tw inally spaced apart perforate walls through which fuel flows towards the engine, the piston and the device being spring biased towards the forward perforate wall proximate the engine, the thermostat being arranged that when the device senses a temperature above a predetermined limit, the piston is urged rearwardly to expose the inlet and allow cooler fuel into the main pipeline thereby to mix with the fuel therein and so lower the temperature thereof. The piston means which obstructs the inlet from the auxiliary pipeline is arranged so that it does not obstruct the flow of fuel to the engine. For this purpose the piston has elongate passageways therethrough.

In another aspect the invention provides a method of heating fuel for an engine prior to passing the fuel into the engine, comprising passing the fuel from a reservoir thereof into an inlet of a heat exchanger means, the heat exchanger means being substantially immersed within hot oil flowing from the engine and through a container within which the heat exchanger means is located, and passing the fuel thereby heated into the combustion chamber of the engine.

Preferably the method includes the step of maintaining the temperature below a predetermined value.

In order that the invention may be well understood, embodiments thereof will now be described by way of example with reference to the accompanying diagrammatic drawings in which; Figure 1 is a vertical sectional view through one embodiment of the invention; Figure 2 is a cross sectional view along line A-A of Figure 1; Figure 3 is a schematic diagram showing another embodiment of the invention; and Figure 4 is a longitudinal sectional view through the thermostat of the embodiment shown in Figure 3.

The same reference numerals are used to identify similar parts in the different embodiments.

The apparatus shown in Figures 1 and 2 of the drawings comprises an outermost generally cylindrical container or canister 1 having a lid closure 2 which, as shown, may be sealed to the canister 1 by means of screw threads 3 or other sealing means. The interior of the canister 1 defines a chamber 4. An inlet 5 is present in the base of the canister 1 as shown and s arranged, in use, to be connected to an outlet from the oil lubrication system of 2 Diesel engine (not shown). A generally cylindrical compartment 6 is located centrally within the canister 1 and standing on a pillar 1-7. The canister and compartment 6 may advantageously be constructed of stainless steel sheet welded or otherwise joined together. The compartment 6 is open at the top to define an entrance 7 and contains as a close fit a body of filter material 8, e.g. of cellulosic fibres, paper or the like. A short length of pipe 9 extends between a hole 10 in the floor 11 of the compartment 6 and an oil outlet 12 in the floor of the canister.

A heat exchanger 13 having an inlet 14 connectable to a fuel reservoir (not shown), and an outlet 15 connectable to the combustion chambers of an associated engine (not shown), is located within the chamber 4. The engine may be a Diesel engine having a high fuel demand. As shown, the heat exchanger 13 comprises a length of tubing, e.g. of copper or like thermally conductive material slightly spaced from and coiled several times about the compartment 6. The outlet 15 is diametrically opposite and vertically above the inlet 14. The diameter of the tubing is large enough not to affect the rate of flow of fuel to the engine and the length is selected according to the level of heating required.

In use, lubrication oil heated by passage through the engine lubrication system is pumped under pressure or drawn under vacuum from the engine through the inlet 5 to fill the chamber t sufficiently to immerse the heat exchanger 13 in the hot oil.

The oil flows continuously in the annular space 16 between the walls of the compartment 6 and the canister 1, through the entrance 7 of the compartment 6 and down through the body of filter material 8, where particles of carbon or metal or water and other harmful materials are removed. The filtered oil then returns via the hole 10 in the floor 11 of the compartment 6 and the pipe 9 to the engine. Meanwhile, fuel is pumped from the reservoir and into the inlet 14 of the heat exchanger coil 13.

During passage through the heat exchanger 13, heat is transferred from the hot flowing oil to the relatively cooler fuel. The fuel then passes under pressure through the outlet 15 and into the combustion chambers of the engine. It will be noted that the oil flows vertically up into the chamber 4 and then down to the outlet 12 through the filter whereas the fuel flows spirally in heat exchanger coils 13. The two fluids thus flow in different directions, i.e. transversely, for efficient heat exchange. We have discovered that with oil circulating at a temperature of about 900C, it is possible to heat the fuel to a temperature of about 40-50 C or more. At such a temperature useful reductions in fuel consumption and other benefits can be achieved. Using such a system, the fuel flow is not substantially restricted thereby avoiding fuel starvation.

Periodically, the body of filter material will become clogged and can be replaced by removing the closure 2 and substituting a new filter for the old filter in the compartment 6.

An adaptor may be present on the inlet to the heat exchanger to adjust the flow rate for different engine sizes.

As shown in Figure 3, a thermostat T may be incorporated in circuit with the apparatus. As shown the thermostat is located at the outlet pipe 15 leading from the apparatus to the fuel injectors of the engine. The thermostat T comprises a length of piping 20 interposed in the main pipeline between the outlet 15 of the apparatus of Figures 1 and 2 and the fuel injectors, not shown. At each end the length is connected by a nut 21 to the adjacent threaded ends of the main pipeline 22. The pipe 20 contains a passageway 23. The length has an inlet port 24 in one side wall connected to an auxiliary pipeline 25 to the main fuel reservoir. The pipeline 25 will typically be much shorter than the length of the heat exchanger coil 13.

A piston 26 having elongate passageways 27 is present in the passageway 23 which includes a forward shoulder 28 to limit its forward travel. The piston 26 is urged forward by a spring 29 biased between a rearward perforate wall 30 and the rearward face 31 of the piston 26. A forward perforate wall 32 is present in the passageway 23 and has a central socket 33 to receive the body of a thermostat sensor 34. The sensor 34 has a rearwardly extending push rod 35 opposite the forward face 36 of the piston 26. 0 rings 37 are present at each end of the length. At rest, the body of the sensor body 34 is in the socket 33 in the forward perforate wall 32, with the piston 26 adjacent thereto and obstructing the inlet port 24.Heated fuel flows forwardly through the rearward perforate wall 30 through the passageways 27 of the piston 26 and through the holes of the forward perforate wall 32 about the sensor body 34. When the temperature of the heated fuel rises above a predetermined limit, say about 45or, the sensor 34 is actuated and the push rod 35 urges the piston 26 rearwardly exposing the inlet 24 according to the distance travelled by the piston 26. Unheated fuel can then flow forwardly from the auxiliary pipeline 25 to join the heated fuel disposed about the sensor 34, the two fuels being mixed on their passage through the holes in the forward perforate wall 32. When the temperature falls below the predetermined limit the sensor retracts and the spring 29 urges the piston 26 forward to obstruct the port 24 again.The parts may be dimensioned so that the unheated fuel will be drawn through the pipe 25, without affecting the flow of the heated fuel.

The apparatus may be provided as a separate accessory, or, for example, the container 1 may be integrally cast into the engine block. Two or more units may be linked together in series to suit engines of larger sizes. The thermostat may be interposed between the fuel outlet pipe and the fuel injectors as shown, or it may be associated with the oil circuit. The apparatus may be used with a petrol engine with appropriate modifications.

Because the fuel is preheated in a controlled way, i.e. to a predetermined temperature range, the fuel is consumed efficiently with much reduced pollution. In evaluations, we have been able to show a saving in fuel cost of up to 15 and the following reductions in exhaust emissions: CO from 60 to 30 ppm and from 50 to 20 ppm NOx from 10 to 4 ppm and from 12 to 5 ppm HCHO down to 0.6 ppm The oil filtration acts to remove all particles larger than 2 micron. Calculations have shown that the distance travelled between oil changes can be extended to 100,000 km.

Claims

1. An engine fuel heating apparatus comprising a container having an inlet for the ingress of hot lubrication oil from the engine and an outlet for the egress of oil back to the engine, a body of filter material being located within the container and arranged so that the oil flowing between the inlet and outlet of the container passes through the body of filter material, heat exchanger means located within the container and arranged, in use, to be substantially immersed within the hot oil flowing between the inlet and outlet of the container, the heat exchanger means having an inlet for the ingress of fuel from a reservoir thereof and an outlet for the egress of heated fuel to the engine and being arranged to pass fuel to the engine.

2. Apparatus according to Claim 1, characterised in that the body of filter material is located within a compartment within the container, the compartment having an open top and a closed floor, a length of pipe extending from a hole in the floor of the compartment to the outside of the container to define the oil outlet.

3. Apparatus according to Claim 1 or 2 characterised in that the heat exchanger means comprises a length of tubing coiled about the compartment.

4. Apparatus according to Claim 3 characterised in that the tubing is formed of copper.

5. Apparatus according to any preceding Claim characterised in that the container has a compartment, the compartment having an open top and a closed floor, an oil filter element being contained within the compartment, an inlet being present in the floor of the container for the ingress of hot lubricating oil from an engine, an oil outlet comprising a pipe extending from a hole in the floor of the compartment to the outside of the container, heat exchanger means comprising a length of tubing coiled about thercompartment and including an inlet for the ingress of fuel from a reservoir thereof, and an outlet for the egress of fuel to the combustion chamber of the engine, the tubing being dimensioned so as not to substantially restrict the flow of fuel to the engine, whereby, in use, hot oil is passed into the inlet of the container through the filter element in the compartment and out through the oil outlet and fuel is passed through the heat exchanger from the inlet to the outlet thereof and the fuel is continuously heated and the oil is continuously filtered.

6. Apparatus according to any preceding Claim characterised in that thermostat control means is present to restrict the temperature to which the fuel is heated.

7. Apparatus according to Claim 6 characterised in that the thermostat is arranged to mix unheated fuel with the heated fuel when the temperature of the heated fuel exceeds a predetermined limit until the temperature of the heated fuel falls below the predetermined limit.

8. Apparatus for heating engine fuel before it reaches the engine at which the heated fuel is to be consumed, the apparatus comprising means for heating the fuel characterised in that thermostat means are present to limit the temperature to which the fuel is heated.

9. Apparatus according to Claim 8 characterised in that the thermostat is arranged to mix unheated fuel and heated fuel when the temperature of the fuel exceeds a predetermined limit until the temperature of the heated fuel falls below the predetermined limit.

10. A method of heating fuel for an engine prior to passing the fuel into the engine, comprising passing the fuel from a reservoir thereof into an inlet of a heat exchanger means, the heat exchanger means being substantially immersed within hot oil flowing from the engine and through a container within which the heat exchanger means is located, and passing the fuel thereby heated into the combustion chamber of the engine.

11. A method according to Claim 10 characterised in that the temperature of the heated fuel is maintained below a predetermined limit, e.g. about 500C.

12. A method according to Claim 10 or 11 characterised in that the temperature is maintained below the limit by adding unheated fuel to the heated fuel until the temperature of the heated fuel falls below the predetermined limit.