Claims:CLAIMS

We claim:
1. A carburetor based fuel injection device (100), comprising
an air intake suction tube (118) having a venturi portion (120) and a throttle valve (102), and
a fuel chamber (110) connected to said suction tube (118) through at least one valve (106), characterized in that:
a controller (104) adapted to operate said at least one valve (106) to supply fuel based on at least one operating parameter.
2. The device (100) as claimed in claim 1, wherein said operating parameter is selected from a group comprising an engine speed, an engine load, a vehicle speed, a throttle valve position, a brake pedal position, a manifold air pressure, air mass flow, temperature, lambda value and the like.

3. The device (100) as claimed in claim 1, wherein said at least one valve (106) is operated based on control signals from said controller (104).

4. The device (100) as claimed in claim 1, wherein said at least one valve (106) is operated by at least one actuating means selected from a group comprising electromagnetic, electrical, hydraulic, pneumatic, and the like.

5. The device (100) as claimed in claim 1, wherein said at least one valve (106) is provided at any one position selected from a group comprising a first position between said fuel chamber (110) and at least one jet (112) connecting said fuel chamber (110) to said suction tube (118), a second position inside said at least one jet (112), and a third position at an orifice of said at least one jet (112).

6. The device (100) as claimed in claim 5, wherein said at least one valve (106) is operated to open and close said orifice of at least one jet (112) connected to said suction tube (118) by any one mode selected from a group comprising fixed duty cycle with constant operating frequency, fixed duty cycle with variable operating frequency, variable duty cycle with constant operating frequency and variable duty cycle with variable operating frequency.

7. A method of supplying fuel to an engine through a carburetor, said carburetor comprising an air intake suction tube (118) having a venturi portion (120) and a throttle valve (102), and a fuel chamber (110) connected to said suction tube (118) through at least one valve (106), said method comprises the steps of:
receiving values of at least one operating parameter related to engine;
controlling operation of said at least one valve (106) based on said at least one operating parameter, and
supplying fuel to said engine through venturi effect.

8. The method as claimed in claim 7, wherein said operating parameter is selected from a group comprising an engine speed, an engine load, a vehicle speed, a throttle valve position, a brake pedal position, a manifold air pressure, an air mass flow, a temperature, a lambda value and the like.

9. The method as claimed in claim 7, wherein said at least one valve (106) is controlled by at least one actuating means selected from a group comprising electromagnetic, electrical, hydraulic, pneumatic, and the like.

10. The method as claimed in claim 7, wherein said at least one valve (106) is operated to regulate fuel flow and air-fuel mixture by opening and closing an orifice of at least one jet (112) connected to said suction tube (118) by any one mode selected from a group comprising fixed duty cycle with constant operating frequency, fixed duty cycle with variable operating frequency, variable duty cycle with constant operating frequency and variable duty cycle with variable operating frequency.
, Description:Field of the invention:
[0001] The present disclosure relates to a carburetor based fuel injection device, and particularly relates to electronically controlling the carburetor as a fuel injection system.
Background of the invention:
[0002] According to a prior art US4084562, a fuel metering device for low fuel feed pressures is described which is adapted for use in an externally ignited internal combustion engine of the air/fuel mixture compressing type having an air-intake suction tube, and which comprises (a) conduit means for conveying fuel to the suction tube of the engine, (b) throttle means of determinable cross-sectional throttle area disposed in the conduit means, (c) bypass duct means for bypassing the throttle means, and (d) control means for switching the bypass means into the fuel flow through the conduit means to bypass the aforesaid throttle means, thereby varying the ratio of the amounts of fuel and air in the mixture being formed in the suction pipe; the control means are responsive to characteristic engine data.
[0003] In carburetors, unintentional delivery of fuel to engine happens during trailing (i.e. downhill driving with throttle closed) wherein ideally no power generation from engine is necessary. Due to the physical fuel metering technique in carburetors, the manifold vacuum causes the fuel to enter into the engine cylinder uncontrolled causing inefficient combustion due to the lack of air with closed throttle condition. This causes hydrocarbon (HC) peaks in emission during trailing and also loss of the fuel which reduces the fuel efficiency of the vehicles fit with carburetors.
Brief description of the accompanying drawings:
[0004] An embodiment of the disclosure is described with reference to the following accompanying drawings,
[0005] Fig. 1 illustrates a block diagram of a carburetor based fuel injection device, according to an embodiment of the present disclosure, and
[0006] Fig. 2 illustrates a method of supplying fuel to an engine through a carburetor, according to an embodiment of the present disclosure.
Detailed description of the embodiments:
[0007] Fig. 1 illustrates a block diagram of a carburetor based fuel injection device, according to an embodiment of the present disclosure. The carburetor based fuel injection device 100, comprises an air intake suction tube 118 having a venturi portion 120 and a throttle valve 102, a fuel chamber 110 connected to the suction tube 118 through at least one valve 106. The device 100 further comprises a controller 104 adapted to control/operate the at least one valve 106 to supply fuel to the suction tube 118 based on at least one operating parameter. A calculated quantity of fuel is supplied to the engine (not shown) through the intake manifold.
[0008] The operating parameter is selected from a group comprising an engine speed, an engine load, a vehicle speed, a throttle valve position/ accelerator pedal position, a brake pedal position, a manifold air pressure, air mass flow, temperature, a lambda value and the like.
[0009] The at least one valve 106 is operated based on control signals from the controller 104. The controller 104 is a dedicated Electronic Control Unit (ECU), or an existing ECU of the vehicle is allowed to control the operation of the at least one valve 106. The at least one valve 106 is controlled/operated by the controller 104 either externally or internally through wired or wireless connection. Further, the at least one valve 106 is operated by at least one actuating means selected from a group comprising electromagnetic, electrical, hydraulic, pneumatic, mechanical and the like. For example: the at least one valve 106 is a solenoid valve. The solenoid valve is also referred to as electromechanical or electromagnetic valve. The fuel metering through the at least one valve 106 is controlled/operated in association with the at least one jet 112 in the carburetor.
[00010] The at least one valve 106 is provided at any one position selected from a group comprising a first position between the fuel chamber 110 and the at least one jet 112 connecting the fuel chamber 110 to the suction tube 118, a second position inside the at least one jet 112, and a third position at an orifice of the at least one jet 112. In the second position, the at least one valve 106 is positioned inside the at least one jet 112 connecting the fuel chamber 110 to the suction tube 118. In third position, the at least one valve 106 is positioned at the orifice (at outlet) of the at least one jet 112 connecting the fuel chamber 110 to the suction tube 118.
[00011] The at least one jet 112 refers to a flow path between the fuel chamber 110 to the suction tube 118. The at least one jet 112 is in fluid communication with a fuel stored in the fuel chamber 110. The commonly known jets comprise a main jet, an idle jet, an air bleed jet and the like. The idler jet, the main jet and other jets are regulated and provide controllability in multiple operating conditions of the engine. The fuel chamber 110 also referred to as a float chamber maintains a constant level of the fuel with the help of a float valve 114. The float valve 114 opens and closes the fuel inlet path 116 based on the level of fuel in the fuel chamber 110, and maintains a constant pressure of the fuel inside the fuel chamber 110. The carburetor based fuel injection device 100 is also operable with or without float valve 114 based fuel chamber 110. The fuel 108 stored in the fuel chamber 110 is selected from a group comprising gasoline/petrol, diesel, flex-fuel and the like.
[00012] The control signals from the controller 104 can be pulses. The at least one valve 106 is operated to open and close an orifice of at least one jet 112 connected to the suction tube 118 by any one mode selected from a group comprising fixed duty cycle with constant operating frequency, fixed duty cycle with variable operating frequency, variable duty cycle with constant operating frequency and variable duty cycle with variable operating frequency. The at least one valve 106 is also controlled by simple ON and OFF pulses and by pulse width modulation (PWM).
[00013] With the improved carburetor design, the controller 104 is able to restrict, block and meter the fuel entry through the at least one jet 112 based on trigger dependent on at least one operating parameter. The at least one valve 106 is also allowed to be positioned between a fuel tank (different from fuel chamber 110) to fuel float valve 114.
[00014] In accordance to another embodiment of the present disclosure, a carburetor with a mechanical valve is provided which operates due to the pressure variations in the suction tube 118.
[00015] In yet another embodiment, a carburetor with a combination of at least two valves 106 is used for at least one jet 112 to meter/ supply fuel to the intake manifold of the engine.
[00016] According to an embodiment of the present disclosure, the at least one valve 106 is actuated to control the fuel metering during normal operation, during trailing to cut-off the fuel or other engine operating conditions which reduces or exceeds the fuel quantity other than the physical request from the engine. The carburetor supports cold start ability by enriching fuel required during start, similar function like a choke in carburetor and start enrichment in Electronic Fuel Injection (EFI). Further, the controller 104 shuts OFF the at least one valve 106 and switches ON based on the fuel cut-off and cut-in strategy of EFI. Still further, the carburetor based fuel injection device 100 is capable to be implemented with a gravity feed fuel injection system, low pressure fuel injection system and fuel injection system with pumps, where the pumps are employed for proving fuel to the fuel chamber 110.
[00017] Fig. 2 illustrates a method of supplying fuel to an engine through a carburetor, according to an embodiment of the present disclosure. The method of supplying fuel to an intake manifold of an engine through a carburetor comprises an air intake suction tube 118 having a venturi portion 120 and a throttle valve 102, and a fuel chamber 110 connected to the suction tube 118 through at least one valve 106. The step 202 of the method comprises receiving values of at least one operating parameter related to engine. The step 204 comprises controlling operation of the at least one valve 106 based on the at least one operating parameter. The third step 206 comprises supplying fuel to the intake manifold through venturi effect. The venturi effect is caused due to the venturi portion 120 of the suction tube 118 and during intake stroke of the engine.
[00018] The operating parameter is selected from a group comprising an engine speed, an engine load, a vehicle speed, a throttle valve position, a brake pedal position, a manifold air pressure, air mass flow, temperature, lambda value and the like.
[00019] The at least one valve 106 is operated by at least one actuating means selected from a group comprising electromagnetic, electrical, hydraulic, pneumatic, mechanical and the like.
[00020] The at least one valve 106 is operated to regulate fuel flow and air-fuel mixture by opening and closing an orifice of at least one jet 112 connected to the suction tube 118 by any one mode selected from a group comprising fixed duty cycle with constant operating frequency, fixed duty cycle with variable operating frequency, variable duty cycle with constant operating frequency and variable duty cycle with variable operating frequency. The at least one valve 106 is also controlled by simple ON and OFF pulses and by pulse width modulation (PWM).
[00021] According to an embodiment of the present disclosure a simplified fuel injection device using a carburetor is provided for the engine. The device 100 provides an improvement or modification in the existing carburetors to derive benefits similar to the fuel injection system. The improvement is introduction of a valve mechanism in between the fuel chamber 110 and the at least one jet 112 in the carburetor, hence controlling the fuel output/metering from the at least one jet 112 based on a requirement. The improved design of the carburetor works similar to the conventional carburetor based on physical air flow and the vacuum pressure in the manifold, however an additional control is obtained to open and close the fuel line based on the control strategy similar to fuel injection system.
[00022] The present disclosure provides an electronically controlled carburetor which includes operating principle of the carburetor with the at least one valve 106 replacing at least one jet 112 or combining the at least one jet 112 and the at least one valve 106 as a single unit. The operation is a combination of carburetor and fuel injection principle.
[00023] The control actuating means is to open and close the at least one valve 106 in synchronization to the manifold under pressure and target fuel metering accuracy. The at least one valve 106 is controlled very similar to a gasoline fuel injector, only difference being the injection strategy. The fuel metering in the present disclosure is based on the manifold under pressure, the air velocity and the opening duration of the at least one valve 106. The improved carburetor combines the benefit of fuel atomization and simplicity of the conventional carburetor and the accuracy and controlled metering like an EFI.
[00024] The present disclosure allows fuel injection with the carburetor in a controlled environment. The control strategy of using a carburetor with at least one valve 106 to behave as a fuel injector. In the present disclosure the fuel metering is based on controlled valve operation with the fuel atomization maintained similar to existing carburetor. Only the basic parts of a carburetor are shown and must not be understood in limiting sense.
[00025] It should be understood that embodiments explained in the description above are only illustrative and do not limit the scope of this invention. Many such embodiments and other modifications and changes in the embodiment explained in the description are envisaged. The scope of the invention is only limited by the scope of the claims.