GB1596796A

GB1596796A - Internal combustion engines

Info

Publication number: GB1596796A
Application number: GB33551/77A
Authority: GB
Original assignee: Cadbury Schweppes Ltd
Current assignee: Mondelez UK Holdings and Services Ltd
Priority date: 1977-08-10
Filing date: 1977-08-10
Publication date: 1981-08-26
Also published as: DE2835099A1; DE2835099C2

Description

(54) IMPROVEMENTS RELATING TO INTERNAL COMBUSTION ENGINES (71) We, CADBURY SCHWEPPES LIMITED, a British Company of Bournville, Birmingham, B30, 2LU, do hereby declare this invention for which we pray that a patent may be granted and the method by which it is to be performed to be described in and by the following statement:- This invention relates to internal combustion engines and in particular to systems for the supply of fuel to such engines.

Developed countries are now acutely aware of the need to economise on the use of oil and oil products, such as diesel fuel for diesel engines, and the present invention is concerned with a proposal for economisingthe use of for example diesel fuel in diesel engines, such as diesel engines of road vehicles.

It is known to mix diesel fuel and water in an emulsifier and to deliver the resulting emulsion to a prime mover which normally uses a diesel fuel, and at least in relation to heavy duty diesel engines, e.g. those over 400 Horse Power, encouraging results have been obtained, suggesting that economies in fuel consumption may be obtained. In the known system, the fuel/water ratio needs to be maintained at predetermined levels over the operating range of the engine.

Any economy of significance in diesel fuel consumption is of interest to us, and accordingly we have researched the use of an emulsion of diesel fuel and water in diesel engines for motor vehicles. Extensive bench tests and road tests on vehicle engines have indicated that in using the known proposal wherein the fuel/water ratio is maintained, no single ratio is suitable for the economy of running at all speeds and powers.

The research has led to the invention that, contrary to expectations and established practice, it is desirable not to use a fixed ratio of fuel to water, and in accordance with the present invention there is provided a system for supplying an emulsion of fuel and water to an internat combustion engine comprising an emulsifier, fuel supply means for the supply of fuel to the emulsifier in which fuel and water are mixed to form a fuel/water emulsion, and water supply means for the supply of the water to the emulsifier in which fuel and water are mixed to form a fuel/water emulsion, which fuel supply and water supply means are arranged so that, over the range of operation of the engine, the percentage of water in the emulsion decreases with increasing fuel supply rate and increases with decreasing fuel supply rate.

Any suitable form of emulsifier may be used, and it is preferred that the water be supplied to the emulsifier at an approximately fixed rate. By this means, when the fuel requirement and supply increases as dictated by engine running conditions, so the percentage of water in the emulsion automatically decreases. It is possible to interlink the fuel and water supplies so that they are related in a particular manner to give a decreasing percentage with increased fuel supply, which is a function other than that achieved by having a fixed water supply rate, although this will probably require a more complex and costly control arrangement.

From the road test carried out with a supply system according to the invention, there is indicated, over the working range of the diesel engine tested, a saving in fuel of the order of 5 /O as compared to running the engine on diesel fuel only,-without loss of performance of the engine, when the fixed supply of water was approximately 8 cc/minute. The amount of water supplied will of course depend upon the engine size.

If an attempt were to be made to use a constant ratio of water to fuel for a diesel engine for a vehicle, the ratio in my view would require to be high in order to gain maximum saving when the engine ticks over the condition in which the fuel consumed is virtually wasted. However, the use of a high water fuel ratio indicates that a high volume water tank, e.g. of the order of 5 gallons would be required and would require refilling as frequently as the fuel tank of a normal vehicle to give a range of 200 miles.

A water tank of this size is not at present considered desirable because of size and also because if an anti-freezing agent such as methyl alcohol were introduced into the water in order to prevent winter freezing, with a 5% concentration of methyl alcohol, the consumption of methyl alcohol by the engine would be significant and the cost of same would negate at least some of the fuel saving advantages.

With the utilization of the invention however, involving the use of an approximately fixed rate of supply of water, a relatively small water tank (of the order of 1 or 2 gallons in volume) can be used, and if methyl alcohol were used to prevent freezing as opposed to using a heater for this purpose, then so much less methyl alcohol would be consumed by the engine.

Notwithstanding the above, some other work in this field suggests that from an environmental point of view it is desirable to have as high a water content as possible in the emulsion. Thus it may be shown in the furure that a large water tank is desirable and it is not intended that the use of a large water tank is to be excluded in this invention.

The final rate of supply of water as related to the supply of fuel will depend upon each application, but obviously if, at any particular engine speed and for any particular engine, the rate of supply of water relative to the fuel is increased beyond a certain point, the engine will stall.

It is desirable that there should be an onoff control valve in the water supply means, preferably where the water supply means connects with the emulsifier, to enable the water supply to be switched off either automatically or by the operator when the engine is stopped.

This invention also provides an internal combustion engine provided with a system as aforesaid.

Embodiments of the invention will now be described, by way of example, with reference to the accompanying drawing, wherein: Figure 1 is a diagram showing the normal fuel supply system of a standard Bedford (Registered Trade Mark) diesel engine as used in the tests referred to, Figure 2 is a diagram similar to Figure 1, but showing how the Bedford engine fuel supply system is modified in accordance with the embodiment of the invention; and Fig. 3 is a diagram similar to Fig. 1, but showing how the Bedford diesel engine fuel supply is modified in accordance with another embodiment of the invention.

Referring to the drawings, and firstly to Figure 1, the engine block of the standard Bedford diesel engine used in the tests is indicated by numeral 10. The fuel supply system illustrated is that as conventionally used with this engine and comprises a fuel tank 12, a lift pump 14 which draws fuel from the tank 12 and supplies it to a filter 16.

Fuel from the filter 16 is delivered to high pressure injection unit 18 which in turn supplies the fuel to the individual cylinder injectors 20. Reference numeral 22 indicates a cold start device which comes into operation in the starting up of the engine by the pressing of a button by the driver and directs surplus fuel through a supply line 24 to the air intake 26 of the engine. The device 22 has a vent 28 to atmosphere, and also has a surplus fuel return connection to a return line 30 at atmospheric pressure leading to the tank 12.

In operation, a small amount of fuel returns from the device 22 through passage 30 to tank 12. There is an additional surplus conduit 32 which leads fuel (still under pressure) from the connection between the device 22 and the injectors 20 to the filter 16 as shown. The surplus return lines are shown in chain-dotted lines in Figure 1, whereas the supply lines to the injectors are shown in full line.

Referring now to Figure 2, this shows how the fuel supply arrangement of Figure 1 was modified for the tests referred to herein. Parts already described in relation to Figure 1 carry the same reference numerals.

The system in Figure 2 involves the emulsification of fuel and water, and the fuel lines indicating the supply of emulsion are shown in double full lines with cross hatching, whilst the surplus return lines carrying surplus fuel-vt lter emulsion are shown in double dotted lines with crosshatching.

The arrangement of Figure 2 differs from Figure 1 in that the lift pump 14 supplies fuel through a first by-pass valve 50 to an emulsifier 52 for providing the emulsion of water and fuel, and the output from the emulsifier 52 supplies the filter 16 through a second by-pass valve 54. A by-pass passage 56 connects the two valves 50 and 54 and the arrangement is such that by appropriate positioning of valves 50 and 54 neat fuel can be supplied from the lift pump 14 along the by-pass pipe 56 to enable the engine to run exactly as described in relation to the arrangement of Figure 1. The valves 50, 54 and by-pass 56 can be omitted if desired.

Connected to the emulsifier 52 is a supply of water contained in the tank 58, the water being supplied through a constant rate delivery pump 60 which supplies water at a fixed rate to the emulsifier 52. The return pipe 30 is passed to a collection tank 62 for collecting the small amount of surplus fuel/water emulsion from device 22, whilst the line 32 returns the normal surplus water and fuel emulsion to the filter 16 as in the arrangement of Figure 1. The water supply line 61 may have an on-off control valve where it is connected to the emulsifier 52.

Such valve, which would be operated automatically or could be under the control of the operator, serves to connect or disconnect the water supply to or from the emulsifier.

In running the engine on a fuel/water emulsion with the arrangement described using a fixed rate pump 60 for the delivery of a fixed amount of water, encouraging results were obtained. The test utilized a perestaltic pump delivering approximately 8 cc's per minute.

The tank 62 was provided for experimental purposes only, as it enabled the surplus not returned to the system to be measured, but in a practical arrangement, it would be desirable to make provision to have the surplus returned to the system for re-use, in order to maximise the available energy in the fuel and the water.

Instead of returning the excess emulsion through conduit 32 to the filter 16, it may be returned to the fuel line as indicated by reference numeral 32A in Figure 2 to the suction side of pump 14.

Referring to Fig. 3, components which are illustrated in and have been described in relation to Fig. 2 have the same reference numerals as are used in Fig. 2 and will not be described in detail. It should be mentioned however that the line marking convention used in Fig. 2 has not been used in Fig. 3. The significant points of the Fig. 3 arrangement as compared to the Fig. 2 arrangement are that the pump 14 discharges neat fuel directly into the filter 16, which in turn delivers to the emulsifier through a check valve 100. A branch 102 from the filter outlet leads to the cold start device 22, so that neat fuel can be delivered to the said device 22 for cold starting. The surplus return line 30 from the device 22 leads surplus neat fuel at atmospheric pressure to the fuel tank 12.

The surplus line 32 from the injectors is returned to the fuel inlet of the emulsifier, after the valve 100.

The water pump 60 delivers water to the emulsifier 52 through a filter 104, a solenoid valve 106, an orifice plate 108 and a check valve 110 to control the flow of water to the emulsifier 52, to ensure constant rate delivery of the water to the emulsifier 52.

The check valves 100 and 110 are nonreturn valves, whilst solenoid valve 106 is an on-off valve which closes when the engine is switched off and opens, after a delay, when the engine starts up. The length of the delay can be varied and the valve 106 can be provided with a manual override if desired.

The orifice plate 108 is used to provide a means of regulating the rate of water flow even if there are pressure fluctuations upstream of the plate 108. By the use of the plate 108 there is permitted the use of a less expensive pump 60 than might otherwise be required.

It is envisaged that the positions of the filter 16 and emulsifier 52 in Fig. 2 can be reversed in the flow sequence, so that the filter filters the neat fuel. It is to be noted in Fig. 3 that the by-pass 56 and valves 50, 54 have been omitted.

Although the modifications of the system described are applied to a standard Bedford engine, it would appear that the invention can be applied to other forms of internal combustion engine such as a Cummins engine, although such engine works on a slightly different principle concerning the return of surplus fuel from the injectors. In the Cummins engine approximately 75% of the fuel supplied to the engine is returned to the fuel tank.

WHAT WE CLAIM IS: 1. A system for supplying an emulsion of fuel and water to an internal combustion engine comprising an emulsifier, fuel supply means for the supply of fuel to the emulsifier in which fuel and water are mixed to form a fueVwater emulsion, and water supply means for the supply of the water to the emulsifier in which fuel and water are mixed to form a fuel/water emulsion, which fuel supply and water supply means are arranged so that, over the range of operation of the engine, the percentage of water in the emulsion decreases with increasing fuel supply rate and increases with decreasing fuel supply rate.

2. A system according to Claim 1, wherein the water supply means is arranged to supply the water to the emulsifier at a fixed rate.

3. A system according to Claim 1 or 2, wherein the water supply means comprises a water tank, a water supply line connecting the tank with the emulsifier and a fixed rate delivery pump.

4. A system according to Claim 3, wherein the water supply line includes an on-off control valve which is automatically operable or operable by an operator to prevent or permit flow of water to the emulsifier.

5. A system according to any preceding Claim, wherein the fuel supply means for supplying fuel comprises a fuel tank and a fuel supply line connecting the fuel tank with the emulsifier.

6. A system according to any preceding Claim, including a by-pass means whereby

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. collecting the small amount of surplus fuel/water emulsion from device 22, whilst the line 32 returns the normal surplus water and fuel emulsion to the filter 16 as in the arrangement of Figure 1. The water supply line 61 may have an on-off control valve where it is connected to the emulsifier 52. Such valve, which would be operated automatically or could be under the control of the operator, serves to connect or disconnect the water supply to or from the emulsifier. In running the engine on a fuel/water emulsion with the arrangement described using a fixed rate pump 60 for the delivery of a fixed amount of water, encouraging results were obtained. The test utilized a perestaltic pump delivering approximately 8 cc's per minute. The tank 62 was provided for experimental purposes only, as it enabled the surplus not returned to the system to be measured, but in a practical arrangement, it would be desirable to make provision to have the surplus returned to the system for re-use, in order to maximise the available energy in the fuel and the water. Instead of returning the excess emulsion through conduit 32 to the filter 16, it may be returned to the fuel line as indicated by reference numeral 32A in Figure 2 to the suction side of pump 14. Referring to Fig. 3, components which are illustrated in and have been described in relation to Fig. 2 have the same reference numerals as are used in Fig. 2 and will not be described in detail. It should be mentioned however that the line marking convention used in Fig. 2 has not been used in Fig. 3. The significant points of the Fig. 3 arrangement as compared to the Fig. 2 arrangement are that the pump 14 discharges neat fuel directly into the filter 16, which in turn delivers to the emulsifier through a check valve 100. A branch 102 from the filter outlet leads to the cold start device 22, so that neat fuel can be delivered to the said device 22 for cold starting. The surplus return line 30 from the device 22 leads surplus neat fuel at atmospheric pressure to the fuel tank 12. The surplus line 32 from the injectors is returned to the fuel inlet of the emulsifier, after the valve 100. The water pump 60 delivers water to the emulsifier 52 through a filter 104, a solenoid valve 106, an orifice plate 108 and a check valve 110 to control the flow of water to the emulsifier 52, to ensure constant rate delivery of the water to the emulsifier 52. The check valves 100 and 110 are nonreturn valves, whilst solenoid valve 106 is an on-off valve which closes when the engine is switched off and opens, after a delay, when the engine starts up. The length of the delay can be varied and the valve 106 can be provided with a manual override if desired. The orifice plate 108 is used to provide a means of regulating the rate of water flow even if there are pressure fluctuations upstream of the plate 108. By the use of the plate 108 there is permitted the use of a less expensive pump 60 than might otherwise be required. It is envisaged that the positions of the filter 16 and emulsifier 52 in Fig. 2 can be reversed in the flow sequence, so that the filter filters the neat fuel. It is to be noted in Fig. 3 that the by-pass 56 and valves 50, 54 have been omitted. Although the modifications of the system described are applied to a standard Bedford engine, it would appear that the invention can be applied to other forms of internal combustion engine such as a Cummins engine, although such engine works on a slightly different principle concerning the return of surplus fuel from the injectors. In the Cummins engine approximately 75% of the fuel supplied to the engine is returned to the fuel tank. WHAT WE CLAIM IS:

1. A system for supplying an emulsion of fuel and water to an internal combustion engine comprising an emulsifier, fuel supply means for the supply of fuel to the emulsifier in which fuel and water are mixed to form a fueVwater emulsion, and water supply means for the supply of the water to the emulsifier in which fuel and water are mixed to form a fuel/water emulsion, which fuel supply and water supply means are arranged so that, over the range of operation of the engine, the percentage of water in the emulsion decreases with increasing fuel supply rate and increases with decreasing fuel supply rate.

6. A system according to any preceding Claim, including a by-pass means whereby

the fuel supply can be caused to by-pass the emulsifier so that the system can be used, selectively, for the supply of neat fuel to the engine.

7. A system for supplying an emulsion of fuel and water to an internal combustion engine substantially as hereinbefore described with reference to Figure 2 or Figure 3 of the accompanying drawings.

8. An internal combustion engine provided with a system according to any preceding Claim connected thereto for the supply of emulsion to the engine.