GB2144799A

GB2144799A - Internal-combustion engines

Info

Publication number: GB2144799A
Application number: GB08320785A
Authority: GB
Inventors: Andrade Gonzalo Moreano
Original assignee: Individual
Current assignee: Individual
Priority date: 1983-08-02
Filing date: 1983-08-02
Publication date: 1985-03-13
Also published as: GB8320785D0

Abstract

To facilitate operation of a spark-ignition engine on diesel oil, or kerosene, the latter is vaporized by heating means eg. a heater h, before it enters the combustion chamber l.The fuel may be heated by a burner, electric means, or the hot exhaust-gases, and may be delivered to the heater from a tank a by a pump c by way of a non-return valve g. The flow-rate may be regulated with a needle valve i. Unheated fuel may be removed through a valve j. The engine may be started, and may be operated thereafter partially, on petrol with the aid of carburetter, Figs. 2 to 4. Diesel oil may be introduced through the carburetter and vaporized in a chamber circumjacent an enlargement in the exhaust manifold, Fig. 5. <IMAGE>

Description

SPECIFICATION Improvements in gasoline and diesel engines This invention relates to improvements in gasoline and diesel engines. Any change, modification or transformation to improve gasoline engines, having as an objective a reduction in the cost of fuel consumed, will be always welcomed, and this invention relates to a system which is directed to that end.

For many years gasoline engines have been subject to a series of improvements in order to improve their efficiency and performance, and both goals have been achieved to a high degree, to the point that the gasoline engine is universally accepted.

Nevertheless, the cost of gasoline has increased greatly so that the engine is becoming economically ineffective in many countries. As a solution to this problem the diesel engine has been adopted and although its construction is expensive, the lower cost of the fuel is a compensation. The idea of this invention is to provide a system which will allow a gasoline engine to run on diesel fuel.

Within a carburettor the vents tri device allows fuel to be vapourized by an air current, resulting in a homogeneous fuel-air mixture to be burned within the cylinder by action of the spark of the spark plug.

There are models of gasoline engines where the carburettor is eliminated and the fuel is injected directly into the cylinder; however in both cases the compression ratio is from 1:7 up to 1:9. When diesel engines were first designed, the fuel was injected into the cylinder as small particles. Later on, pumps and injectors were used and the compression ratio of the new engine was from 1:12 up to 1:24 in order to obtain compressed air at a very high temperature, so that the diesel fuel was ignited thereby.

In summary, the engines described above can only run with gasoline or diesel fuel, with no possibility of change.

This invention presents an alternative of how to improve the ignition properties of diesel fuel so that it can be used with gasoline engines, but before going into details, it is important to take a look at the following table: Properties Gasoline Diesel fuel Specific weight (kg/dm3) 0.73 (average) 0.87 (average) Caloric Power (Kcal/Kg) 11.110 (average) 10.800 (average) Chemical Composition 85% Carbon 86% Carbon 15% Hydrogen 14% Hydrogen Inflammability Maximum Reduced Gasoline and diesel fuel are similar in specific weight, caloric power and chemical composition, but differ in their viscosity, volatility and inflammability.However, in the case of diesel fuel, if we increase its temperature up to 300"C it will work like gasoline or even better, and then if we make a good air-diesel mixture it will burn inside the cylinder by action of the spark of the spark plug. This is the basis of the present invention for using diesel fuel in gasoline engines.

Considering a gasoline engine, it is to be noted that almost always the intake manifold is located on the exhaust manifold. This configuration allows the liquid particles of gasoline to be heated before entering the cylinder, so that they enter as vapour. If diesel fuel is used instead of gasoline the liquid particles will not enter the cylinder as vapour, because they need to be heated longer and at higher temperatures. To use diesel fuel in a gasoline engine, therefore, it is necessary to consider ways of vapourizing it, this being the only way that the molecular, dry particles of diesel fuel can mix well with the air and be burned in the cylinder by action of the spark.

A system for achieving this is shown in Figure 1. This comprises a fuel pump (c) which can be run by an electric motor or by the gear cam or other system. The pump (c) suctions fuel (a) from a tank (b) via a suction pipe (d). If the pump has a return line, the diesel fuel is fed back to the tank (b) via the pipe (e). A check valve (g) allows the diesel fuel to pass via a line (f) through a heater(h) at high temperature, which could be electric, or provided with a burner, or could be designed to use the hot gases of the exhaust manifold to heat the diesel fuel until it is converted to vapour in sufficient quantities to be used by the engine.

From the heater (h) the vapour passes via the line (f) to a needle valve (i). This valve controls exactly the amount of vapour entering the intake manifold (x). Opening or closing of the valve (i) causes more or less vapour to pass through it, thereby increasing or decreasing the acceleration of the engine. A valve (j) serves to drain the system, taking out some liquid diesel fuel which could remain in the pipe (f) when the engine is not running with diesel fuel. A relief valve (not shown in Figure 1) is provided in the line (f) in order to avoid any accidental over pressure in the line.

The system operates as follows: The diesel fuel leaves the tank, passes through the pump (c) and valve (g), is then vapourized by the heater (h) and passes as vapourthrough the needle valve (i) which controls the amount of fuel into the intake manifold (x) where the vapour mixes with air (k). The air-diesel mixture passes through a valve (y) filling the combustion chamber (1) by suction of piston (A), and the mixture is compressed by the piston (A) and is ignited by the spark of the spark plug (z).

The system of Figure 1 works well when the engine is running, but it is difficult and complex to get it started. To avoid this the system of Figure 2 may be used.

Keeping the original carburettor and starting the engine with gasoline, ignition will be immediate, because the gasoline enters the engine as vapour. It may be helpful at this point to summarize the operation of a carburettor. The air (k) enters through the intake manifold (x) creating a vacuum in the pipe (v) and absorbing gasoline as very fine particles, which are vapourized by contact with the air. The air-gasoline mixture passes a butterfly valve (throttle valve) (s) and then enters the cylinder.

The needle valve (q) is open, so the gasoline (p) from the fuel tank (o) can go to the intake manifold (x). The carburettor has another needle valve (r) to control the minimum speed, and a float (n) to maintain the level of gasoline (p) in the fuel tank (o), closing or opening the valve (u) which allows the fuel to pass through the pipe (m).

Before the engine is initially started, it is recommended to decrease the air flow (k) by closing the butterfly valve (t), so as to obtain a rich mixture and quick ignition. In this case the needle valve (i) is closed and the engine runs normally on gasoline.

When the engine has been running for 10 minutes on gasoline, the system of the invention goes into action (see Figure 3) to vapourize the diesel fuel, and at the same time the changeover of fuel is made. The drain valve (j) opens for a while to drain the liquid diesel fuel from the pipe (B) and when there is vapour in the pipe (f) the drain valve closes. The transfer of fuel (diesel) is made by the needle valve (i) and at the same time the valve (q) closes. The butterfly valve (s) opens completely and the air flow passes through it (k), mixed with the diesel fuel vapour. The fuel-air mixture will thus pass through the valve (i) and from it into the cylinder.

When the engine is running with gasoline, the trottle valve (s) controls the acceleration; when it is running with diesel fuel, the valve (i) performs this function.

The device which effects the fuel changeover could be manual or automatic, depending on the degree of complexity which is desired or acceptable, but it should carry out the steps described above.

If for some reason the gasoline engine does reach the optimum temperature for inflammability of the diesel fuel, it is possible to open the needle valve (q) a little (see Figure 4) to add a small amount of gasoline to the air-diesel mixture, but not more than 5 or 10%, to increase the inflammability ofthe fuel.

The above system can use a variety of pumps, heaters, needle valves and so forth, and there are a large number of types on the market. The same can be said for the device which changes the fuel from gasoline to diesel fuel.

One interesting feature of this invention is that the system can work with diesel or kerosene or any fuel which can be vapourized. A large number of experiments were made with an air-cooled gasoline engine of 5 HP, with a compression ratio of 1:8 and with 3,600 RPM. It was possible without undue experimentation, to get the desired result. The engine ran on diesel fuel for a long time, and it is interesting to note that the combustion was very clean. As a test, the fuel feed (gasoline) was taken out, and the tank (o) was empty. The engine continued to run with no problems and only stopped when the valve (i) was closed. It is also a possibility to use the system of this invention with an engine where there is direct injection of fuel into the cylinder, and this should also work properly because all that is needed is to get the fuel vapourized.In this invention it is also possible to change elements without altering the fundamental principle of vapourization of fuel before it enters the cylinder. Thus, it is possible to use the carburettor as a regulator of the fuel-air mixture and as a device to get very fine liquid particles of diesel fuel which will be transported by the air into the engine. The only problem to be resolved is to transform the liquid particles into vapour, because it is the only way the diesel fuel can be burned in the cylinder and, as stated above, the liquid particles need high temperatures and longer time to become vapourized, and this may be achieved if the intake manifold is heated from an electrical source or, preferably, if the intake and exhaust manifolds are connected to form a heat exchanger.

Looking at Figure 5, we can see that in a gasoline engine (D) the exhaust manifold (E) increases its diameter to provide a major surface on which the liquid particles of diesel coming from the carburettor will be vapourized. The intake manifold (F), which covers the exhaust manifold (E), will transport the air-fuel mixture as vapour into the cylinder. The design of heat exchanger will depend on the type of engine to be modified, and in some engines will be easier to achieve than in others. If this approach is followed the carburettor needs to be adjusted to allow a better diesel fuel flow.

With the system described above, any gasoline engine can work with diesel fuel and the invention may lead to improved diesel engines because the compression ratio is reduced with this new system and thus eliminates the need for pumps and injectors. Furthermore, clean combustion is achieved.

To summarize, we set out below a list of various features and advantages of the invention and/or embodiments thereof: 1. The system works with a series of elements such as pump, heater, valves, etc., which properly combined allow any gasoline engine to run with diesel fuel.

2. Through this new system the diesel fuel can change from liquid to vapour providing an easy and clean combustion.

3. Thanks to this system it is possible to supply diesel vapour to the intake manifold or directly to the cylinder, resulting in a similar efficiency in both cases.

4. It is not necessary to make any major change to the engine or its parts; just adding this system gives vapourization of diesel fuel.

5. If the gasoline engine does not achieve the optimum temperature it is possible to add a small amount of gasoline to provide better inflammability.

6. It is possible to start the engine using the original carburettor and gasoline as fuel.

7. Making a diesel engine will be easier in the future, because using this system there is no need to have pumps, injectors and a high compression ratio.

8. It is possible to join together the intake and exhaust manifolds making an efficient heat exchanger where the very fine liquid particles of diesel fuel become vapourized before entering the cylinder.

9. It is possible to install only an electrical heater in the manifold intake for the purpose of vapourizing diesel fuel.

Claims

1. A device for feeding fuel to an internal combustion engine having at least one cylinder in which fuel is ignited by a spark plug, comprising a source of a liquid fuel and means for heating the liquid fuel to a temperature high enough to vapourize it.

2. A device according to claim 1, wherein the heater comprises a heat exchanger in which, in use, a flow of hot exhaust gases heats incoming liquid fuel.

3. A device according to claim 2, wherein the said heat exchanger comprises an enlarged engine outlet manifold portion through which, in use, the hot exhaust gases flow.

4. A device according to claim 1, wherein the heater is an electric heater.

5. A device according to claim 1, wherein the heater comprises a burner.

6. A device according to any preceding claim, comprising means located downstream of the heater for draining off any remaining liquid fuel.

7. A device according to any preceding claim, wherein the liquid fuel is diesel fuel.

8. A device according to claim 7, further comprising a source of liquid gasoline, means for leading vapour thereof to the engine, and means for controlling selectively the introducing into the engine of gasoline only, diesel fuel only, or a mixture of gasoline and diesel fuel.

9. A device according to claim 8, wherein the said controlling means is manual.

10. A device according to claim 8, wherein the said controlling means is automatic.

11. A device for feeding fuel to an internal combustion engine, substantially as herein described with reference to Figure 1, or Figures 2 to 4, or Figure 5, of the accompanying drawings.

12. An internal combustion engine having at least one cylinder in which fuel is ignited by a spark plug, in combination with a device according to any preceding claim.