Fuel Supply System for an Internal Combustion Engine

Field of the invention:

The present invention relates to "Fuel Supply System for an Internal Combustion Engine" and more particularly to fuel supply system for an internal combustion engine of a two wheeler.

Background of the Invention:

Internal Combustion Engines convert the chemical energy available in fuels like petrol, diesel, LPG and CNG into mechanical energy by igniting the combustible air -fuel mixture inside a combustion chamber. Internal Combustion Engines can be classified into spark ignition engines and compressed ignition engines on the basis of means of igniting the fuel. A spark is produced across a spark gap for igniting the combustible air fuel mixture in the case of spark ignition engines. The air - fuel mixture is sucked into the combustion chamber by the low pressure created during the suction stroke.

The air - fuel mixture required for combustion is generally prepared either by a carburettor or by fuel injection. In case of carburettor, the fuel stored in petrol tank mixes with filtered air inside a carburettor because of the low pressure created by intake air rushing through it and the air - fuel mixture is delivered to the inlet manifold of the engine. The quantity of air - fuel mixture delivered to the inlet manifold is controlled by a throttle cable which is in turn connected to a throttle pipe or accelerator pedal.

Whereas in case of fuel injection, the fuel is atomized by forcibly pumping it through a small nozzle at high pressure created by a fuel pump. The fuel pump is typically mounted in a fuel tank. A fuel injector acts as a fuel - dispensing nozzle. It injects liquid fuel directly into the engine's intake air stream. An Engine Control Unit (ECU) calculates the amount of fuel that has to be injected for complete combustion based on signals received from Manifold Air Flow (MAF) sensor, Throttle Position Sensor (TPS), Engine Speed Sensor etc and provides appropriate signal to fuel injector solenoid which in turn delivers the high pressure fuel.

Fuel injection has several advantages over carburettor mechanism of fuel delivery, since the amount of fuel injected can be accurately controlled, improved driveability, reduced emissions and increased fuel efficiency can be achieved. The high cost of a Fuel Injection System and the large number of parts of Fuel Injection System prevent its widespread use for Spark Ignition Engines.

Therefore it is an object of the present invention to provide a fuel supply system which overcomes the above limitation.

Summary of the Invention:

The present invention has been devised in view of the above limitation and it is therefore an object of the present invention is to provide a fuel supply system which can be used for spark ignition engines.

Another object of the present invention is to eliminate the use of fuel pump in the fuel tank.

Another object of the present invention is to provide a fuel supply system which employs less number of parts for its working.

Another object of the present invention is to provide a fuel supply system which is cost effective.

Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.

Brief description of the Drawings:

The present invention will become more fully understood from the detailed description given herein below and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention, and wherein

FIG. 1 illustrates a conventional two wheeler.

FIG. 2 shows the fuel supply system according to the present invention.

FIG. 3 shows the connection of elements of fuel supply system according to the present invention.

Detailed Description of the Invention:

It is further to be noted that the present invention is not limited to the described embodiment and many other changes and modifications may be made without departing from the scope of the appended claims.

A preferred embodiment of the fuel supply system of an automobile according to the present invention will be described hereunder. The present invention is applied to a two wheelers.

Embodiments of the present invention now be described with reference to the accompanying drawings. In the following description, "front", "rear", "upper", "lower", "right", "left" and "bottom" represent directions viewed from the perspective of the vehicle rider.

Drawing reference to Figure.1 a motorcycle comprises of a frame (101), front fork (102) attached to a pivot tube (103) of the vehicle frame, a front wheel (104) attached to these front forks (102), a handle bar (105) connected to the front forks (102), a fuel tank (106) attached so as to straddle an upper part of the vehicle frame, a seat (107) attached to the upper rear portion of the vehicle frame, an engine unit (108) attached to the lower front section of the vehicle frame, a swing arm (109) attached to a lower rear section of the vehicle frame, suspended by a rear shock absorber (not shown in the drawing) from the vehicle frame and a rear wheel (110) attached to a rear end of swing arm (109). The intake system of the engine comprises of a carburettor (117), intake duct and an air cleaner. The exhaust system of the engine comprises of exhaust pipe and a muffler. The motorcycle is also provided with a side cover (111) for covering a side section of the vehicle frame, a seat cover for covering a rear section of the vehicle frame below the seat, a front fender (112) for covering an upper part of the front wheel (104), and a rear fender (113) for covering an upper part of the rear wheel (110). The drive from the engine (108) is transmitted from the engine to the driven wheel sprocket mounted on the rear wheel hub mounted on the rear wheel assembly.

Referring to Figure 2, a fuel tank (201) is provided which comprises two expandable elastomeric compartments (202, 203) separated by a double partition wall. One compartment is provided for filling fuel otherwise known as 'Fuel Compartment'

(203) and the other compartment is for filling Compressed air otherwise known as 'Compressed Air Compartment' (202). During refuelling of the vehicle, both compartments are filled with fuel and compressed air respectively. The compressed air in the compressed air compartment (202) exerts a pressure on the Fuel Compartment (203) by virtue of the expandable nature of the compartments. The fuel outlet of the Fuel Compartment is connected to a solenoid (204) which is controlled by an Engine Control Unit (ECU) (205). The said solenoid (205) has two outlets, one connecting to the carburettor (206) and the other to fuel Injector (207). A pressure sensor (208) connected to the Fuel Compartment (203) provides fuel pressure signal to the ECU (205). The said ECU (205) allows the pressurized fuel to flow into the fuel injector for fuel pressure values greater than a predetermined level. When the fuel pressure falls below the predetermined level, the ECU switches the solenoid to provide fuel supply to the carburettor.

In the said fuel supply system the high pressure required for fuel injection is produced by means of compressed air stored in one of the two expandable elastomeric compartments of the fuel tank.

Figure 3 shows the preferred connection between various elements of the fuel system described above which can be used for any vehicle having at least two wheels.

The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the claims.

We Claim:

1. A fuel supply system for an internal combustion engine comprising:

a fuel tank having at least two expandable elastomeric compartments;

a pressure sensor for sensing the fuel pressure inside the fuel tank;

a solenoid connecting one compartment to a carburettor and a fuel Injector; and

a controller for actuating the solenoid based on pressure sensor input.

2. The fuel supply system as claimed in claim 1, wherein the said two elastomeric compartments are preferably compressed air compartment and fuel compartment,

3. The fuel supply system as claimed in claim 1 and claim 2, wherein the said compressed air compartment is placed closed to fuel compartment.

4. The fuel supply system as claimed in claim 1 and claim 2, wherein the said compressed air compartment is placed in such a way that it exert pressure on fuel compartment.

5. A fuel supply system for an internal combustion engine of a vehicle having at least two wheels comprising:

a fuel tank having at least two expandable elastomeric compartments;

a pressure sensor for sensing the fuel pressure inside the fuel tank;

a solenoid connecting one compartment to a carburettor and a fuel Injector; and

a controller for actuating the solenoid based on pressure sensor input.