Claims:We claim:
1. A dual fuel operation mode switch system (300) comprising:
an input selecting unit (240,230) configured to send an input to an ECU unit (305);
said ECU unit (305) electrically configured to control a gas flow valve (201) based on said input.
2. The dual fuel operation mode switch system (300) as claimed in claim 1, wherein said input selecting unit being a fuel knob (240),
wherein, said fuel knob (240) comprises plurality of positions,
wherein, said plurality of positions being a first position to turn OFF the fuel supply; a second position to enable a gas power mode and a third position to enable gas economy mode.
3. The dual fuel operation mode switch system (300) as claimed in claim 2, wherein said fuel knob (240) is configured to a fuel reservoir (307) to send a fuel to a fuel pressure reducer (200).
4. The dual fuel operation mode switch system (300) as claimed in claim 1, wherein said input selecting unit being a switch unit (230),
wherein, said switch unit (230) electrically configured to a fuel knob (240); and
said switch unit (230) comprises a liquid fuel mode, a neutral mode, a gas fuel mode and a gas power mode.
5. The dual fuel operation mode switch system (300) as claimed in claim 1, wherein a gas flow valve (201) being configured to receive said fuel from said fuel pressure reducer (200).
6. The dual fuel operation mode switch system (300) as claimed in claim 5, wherein said ECU unit (305) electrically controls said gas flow valve (201) through a fuel control signal (106).
7. The dual fuel operation mode switch system (300) as claimed in claim 1, wherein said fuel pressure reducer (200) comprises of a primary chamber (205) and a secondary chamber (203).
8. The dual fuel operation mode switch system (300) as claimed in claim 7, wherein said secondary chamber (203) being connected to said gas flow control valve (201) and said secondary chamber (203) of said fuel pressure reducer (200) is configured to receive a fuel from the primary chamber (205).
9. The dual fuel operation mode switch system (300) as claimed in claim 1, wherein said primary chamber (205) being connected to a fuel reservoir (307) through a fuel pressure line (304).
10. A method of operating a dual fuel operation mode switch system (300) in a vehicle (100) comprising the steps of:
switch ON the ignition key of a vehicle (100);
selecting a fuel type through a switch unit (230);
selecting an input from an input unit; and
sending a fuel control signal to a gas flow control valve (201).
11. The method of operating a dual fuel operation mode switch system (300) as claimed in claim 10, wherein said selecting said input unit comprising the steps of:
sending a fuel control signal to said gas flow control valve (201) when a gas economy mode being selected;
sending no fuel control signal to said gas flow control valve (201) when a gas power mode being selected.
12. The method of operating a dual fuel operation mode switch system (300) as claimed in claim 10, wherein said selecting said input from said input unit comprises the steps of:
selecting an input from a fuel knob (240);
shutting OFF fuel supply when a first position selected;
entering into a gas power mode when a second position selected; and
entering into a gas economy mode when a third position selected.
13. The method of operating a dual fuel operation mode switch system (300) as claimed in claim 10, wherein said selecting said input from said input unit comprising the steps of:
selecting an input from a switch unit (230);
turning ON liquid fuel supply when a liquid fuel mode selected;
turning OFF a gas fuel and liquid fuel when a neutral mode selected;
entering into a gas power mode when a gas power mode selected; and
entering into a gas economy mode when a gas economy mode selected. , Description:
TECHNICAL FIELD
[0001] The present subject matter generally relates to a vehicle. The present subject matter specifically but not exclusively relates to a duel fuel operation mode switch system.
BACKGROUND
[0002] In recent times there is an increased demand to control emissions from automobiles, in view of environmental issues. As a result, use of alternative fuels has been given enough consideration to replace or to reduce the emissions. Natural gas is of the alternative fuel to fuel oil and natural gas is used to run vehicles specially passenger vehicles. The natural gas is compressed to a high pressure and therefore called as compressed natural gas (CNG).
[0003] In order to facilitate the smooth operation of the vehicle running on CNG, a CNG tank, a high pressure pipe, a solenoid valve is provided in the upstream of the high pressure pipe to control the amount of gas fuel reaching into the engine.
BRIEF DESCRIPTION OF THE DRAWINGS
[0004] The detailed description is described with reference to an embodiment of a three wheeler vehicle along with the accompanying figures. The same numbers are used throughout the drawings to reference like features and components.
[0005] Fig. 1 illustrates a side view of a motor vehicle, as per one embodiment of present subject matter.
[0006] Fig. 2 illustrates a dual fuel operation mode switch system, as per one embodiment of present subject matter.
[0001] Fig. 3 illustrates a dual fuel operation mode switch system, as per another embodiment of present subject matter.
[0002] Fig. 4 illustrates a flow chart of method of operating the dual fuel operation mode switch system, as per one embodiment of present subject matter.
[0003] Fig. 5 illustrates a flow chart for an operation of an embodiment of the present invention involving the fuel knob.
[0004] Fig. 6 illustrates a flow chart for an operation of an another embodiment of the present invention involving the switch unit.

DETAILED DESCRIPTION
[0005] The output of the high pressure gas pipe or a gas pressure reducer is directly connected to the gas solenoid. The gas solenoid controls the flow of gas to the engine of the vehicle. The gas pressure sensor and the gas temperature sensor are mounted on the gas pressure reducer before the gas solenoid. The gas fuel supply is controlled by a switch which can also enable the user of the vehicle to switch between the type of fuel such as a liquid fuel and a gaseous fuel.
[0006] For a dual fuel vehicle designed to work on a liquid fuel such as a petrol as well as a gaseous fuel such as CNG, the user of the vehicle has to switch between the type of fuel to be used depending on the requirement and depending on the availability / supply of type of fuel. In order to switch between the type of fuel, the user has to keep on switching between the dedicated switches available for the gas fuel and the liquid fuel. Further, the user needs to run the vehicle either in an economy mode or a power mode which demands variation in the metering of the fuel. This variation in the demand of the metering necessitates incorporating additional button for making the vehicle run in a particular mode. Further, the gas fuel is highly combustible and demands for a safety operation in a vehicle so that the fuel does not leak when any fracture or crack occurs in the fuel pipe connected to the gas fuel reducer and the engine. Thus there exists a challenge of proving a improved fuel switching system for fuel supply of an engine which can overcome all the above problems and other problems of known art.
[0007] Hence, the present subject matter provides an improved dual fuel operation mode switch system. The dual fuel operation mode switch system enables the user of the vehicle to switch between the type of fuel to be used and a mode of operation for a gaseous fuel in which the user prefers to drive the vehicle.
[0008] As per an aspect, the present subject matter provides a dual fuel operation mode switch system with a switch unit, which is configured to a ECU (Electronic control unit). The ECU unit is configured to receive an input signal from an input unit such as a switch unit or a fuel knob disposed on a fuel reservoir of the dual fuel operation mode switch system.
[0009] Yet another aspect of the present subject matter provides a dual fuel operation mode switch system having an input unit which is capable of switching between a liquid fuel and a gaseous fuel. Further, upon selection of the type of fuel, the input unit is configured to send a mode signal to the ECU unit in order to activate a driving mode of the vehicle such as an economy mode and a power mode. The ECU unit is configured to receive the mode signal from the switch unit in order to control a gas flow valve of the fuel pressure reducer to control the fuel flow into an engine of the vehicle and to operate the vehicle in a used selected mode.
[00010] Still another aspect of the present subject matter provides an ECU unit configured to send a fuel control signal to the gas flow control valve of the fuel pressure reducer in accordance with the selected driving mode. The gas flow control valve is a gas solenoid which has pins to electrically connect to an Engine control unit (ECU) of the vehicle. The gas flow control valve is configured in a way to control the flow of the gaseous fuel into the engine of the vehicle.
[00011] Another aspect of the present subject matter provides a dual fuel operation mode switch system where a fuel reservoir comprises of a primary chamber and a secondary chamber. The secondary chamber, connected to the gas flow control valve, of the fuel pressure reducer is configured to receive a fuel from the primary chamber. The primary chamber is connected to a fuel reservoir through a fuel pressure line. The embodiments of the present invention will now be described in detail with reference to an embodiment in a three wheeled vehicle along with the accompanying drawings. However, the present invention is not limited to the present embodiments. The present subject matter is further described with reference to accompanying figures. It should be noted that the description and figures merely illustrate principles of the present subject matter. Various arrangements may be devised that, although not explicitly described or shown herein, encompass the principles of the present subject matter. Moreover, all statements herein reciting principles, aspects, and examples of the present subject matter, as well as specific examples thereof, are intended to encompass equivalents thereof.
[00012] Fig. 1 illustrates a side view of a motor vehicle (100). In an embodiment, a front compartment including a head tube (not shown) that mounts a handle bar assembly (106) of the motor vehicle (100) and the head tube (not shown) is capable of steering a front wheel (101). A driver seat assembly (104) that is housed on a front portion (F) of the motor vehicle (100) and facing towards the handle bar assembly (106). The motor vehicle (100) also includes a pair of rear wheels (102) and a front fender (103) disposed above the front wheel (101). A CNG cylinder etc. is housed in a housing area (110) under the driver seat assembly (104). The cylinder is a fuel reservoir (307) (refer fig. 4) which provides gas fuel to the engine (306) of the motor vehicle (100). The fuel in the fuel reservoir (307) is at a very high pressure and need to be reduced by a fuel pressure reducer (200) (refer fig. 2). The front wheel (101) is controlled by a braking system (121) (shown in fig.1a) which implements a rotator potentiometer, an actuator, a pressure sensor. For instance, the braking system of the present invention works on the principle of brake by wire. In an implementation, the brake by wire technology utilizes the electrical power to generate force that is transmitted to the master cylinder piston instead of direct application of force from the pedal. This assist follows a characteristic that is dependent on the pedal travel as well as the difference in pressure between the set value and the brake line pressure. As a result of this, the amount of pedal force that has to be applied by the driver to stop the vehicle within a designated stopping distance is greatly reduced. Consequently, in a vehicle equipped with a brake by wire technology, the driver needs to apply only a lesser force at the pedal for the vehicle to stop within a given distance, than in a vehicle fitted with a conventional brake system.
[00013] In an implementation, the brake by wire system of the present invention may include a brake pedal attached to a rotary potentiometer, a control unit, an actuator, pressure sensor and the conventional parts such as master cylinder, a plurality of bundy tubes, wheel cylinder, back plate assembly which includes the brake shoes and the wheel cylinder. The potential difference created in the rotary potentiometer when the brake pedal is turned while pressed by the driver’s foot is given as an input to the control unit and the actuator pushes the push rod in master cylinder based on the amount of pedal turn as quantified by the rotary potentiometer. A pressure transducer is present in the brake line which measures the pressure and sends the signal to the control unit. If the pressure in the line is less than the required pressure for that pedal travel set in the control system then the control unit pushes further until the required pressure in line is achieved there by ensuring the added safety with the help of this closed loop control. Similarly, if the pressure is more than the set value then the actuator relieves the push rod until the required pressure is reached. The other parts of the brake system work in the conventional way, the brake fluid pressure reaches the wheel cylinder through the bundy tube and the cylinder in turn pushes the brake shoes against the drum thereby braking the vehicle. The same concept may be applied for a disc brake vehicle wherein the piston of the brake system is actuated to brake the vehicle.
[00014] Fig. 2 illustrates a dual fuel operation mode switch system (300) as per the present invention. The dual fuel operation mode switch system (300) comprises a fuel reservoir (307), which is configured to send a fuel to a fuel pressure reducer (200). The fuel reservoir (307) is configured with a fuel knob (240). In an embodiment, the fuel knob (240) is electrically connected to an ECU (305) to communicate signal. The fuel knob (240) enables the user to select different modes of operation of vehicle viz, an economy mode and a power mode. The fuel knob (240) has three different positions and one of the positions of the fuel knob (240) is a first position to turn OFF the fuel supply. The second position of the fuel knob (240) enables the selection of the power mode. The third position of the fuel knob (240) enables the selection of the economy mode. Each position of the fuel knob (240) corresponds to an input signal which is received by the ECU (305). The first position as an input is processed by the ECU (305) to control the fuel reservoir (307) to not to release the fuel and hence the first position of the fuel knob (240) functions as safety feature. The output from the fuel reservoir (307) via the fuel knob (240) is connected to an inlet of a fuel pressure reducer (200). The fuel pressure reducer (200) receives a fuel from the fuel reservoir (307) at a higher pressure P1 (~5 to 10 bar). The pressure inside the fuel reservoir (307) may vary based on the amount of fuel stored inside the fuel reservoir (307). The fuel pressure reducer (200) comprises a spring (not labelled), a diaphragm (not labelled) and a lever (not labelled) which enables reduction of the pressure of the fuel inside a secondary chamber (203). The pressure of the fuel is reduced in two stages. At a first stage the fuel pressure is reduced and maintained around P2 (1~1.5 bar gauge pressure) and at a second stage the fuel pressure is reduced and maintained around P3 (0.2 ~ 0.5 bar gauge pressure).
[00015] The fuel pressure reducer (200) has a primary chamber (205) and a secondary chamber (203). The outlet of the secondary chamber (203) of the fuel pressure reducer (200) is connected to the gas flow control valve (201). The secondary chamber (203) is configured to receive the fuel from the primary chamber (205). The fuel received from the primary chamber (203) is of lower pressure compared to the fuel inside the fuel reservoir (307). The primary chamber (205) is connected to a fuel reservoir (307) through a fuel pressure line (304).
[00016] The fuel is supplied to an engine (306) of the vehicle (100) through the gas flow control valve (201). The gas flow control valve (201) is connected to the ECU (305) which controls the flow of the fuel into the engine (306) based on the signal received by the ECU unit (305). In an embodiment, a switch unit (230) (shown in Fig 3) is securely disposed on the fuel reservoir (307) in between the fuel knob (240) and the ECU (305). The gas flow control valve (201) is operational based on a power mode or an economy mode selection done by the switch unit (230). The gas flow control valve (201) such as a gas solenoid restricts and vary the fuel flow when the driving mode gets enabled by selecting the economy mode or the power mode. With additional engine inputs, the engine control unit (not shown) with predefined map / lookup table, gives input to the gas flow control valve (201). The gas flow control valve (201) opens and closes based on the afore mentioned input received by the fuel knob (240). The electronic control unit (ECU) receives input from the fuel knob (240) and gas is supplied to the engine intake system depending on the input. The gas flow control valve (201) gets fully opened when the power mode is enabled. In second position corresponding to the power mode, the gas flow control valve (201) is not operational and the flow of the fuel depends or directly proportional to vehicular parameter such as throttle opening. In the third position which is the economy mode, the gas flow control valve (201) is restrictively opened.
[00017] The gas flow valve (201) is configured to receive the fuel from the fuel pressure reducer (200). In another embodiment, (refer. Fig. 3 ) the ECU unit (305) is electrically configured to receive one or more input signal from a switch unit (230) to control the gas flow control valve (201) and the fuel knob (240) functions as a mechanical knob to switch ON/OFF the fuel supply from the fuel reservoir (307). The ECU unit (305) of dual fuel operation mode switch system (300) electrically controls the gas flow valve (201) through a fuel control signal (116). The switch unit (230) is electrically configured to send a mode signal and a fuel signal to the ECU unit (305). The mode signal is an economy mode or a power mode whereas the fuel signal is a liquid fuel signal or a gas fuel signal. As per an embodiment, the liquid fuel signal is used when the vehicle enters in a limp home mode or when the gas fuel is not sufficient to operate the vehicle. The liquid fuel signal corresponds to a neutral position. The switch unit (230) is provided with four positions, in an embodiment, which corresponds to a neutral position for neutral mode, a liquid fuel position for liquid fuel mode and a gas position for gas mode. The gas position has a gas economy position and a gas power position.
[00018] Fig. 4 illustrates a flow chart of method of operating the dual fuel operation mode switch system (300). In step 501, the ignition key (not shown) of the vehicle (100) is switched ON. In step 502, the type of fuel is selected through the switch unit (230). The switch unit (230) sends the fuel signal to the ECU unit (305). When the liquid fuel is selected then a liquid fuel signal is sent to the ECU unit (305) to identify the liquid fuel (e.g. petrol) and supply the liquid fuel to the engine. Similarly, if gaseous fuel is selected then a gaseous fuel signal is sent to the ECU unit (305) to identify the gaseous fuel (e.g. CNG) and supply the gaseous fuel to the engine. After the gaseous fuel is selected, the user selects the driving mode such as an economy mode or a power mode, in step 503. The ECU unit (305) receives the mode signal from the switch unit (230) and a fuel management system in the ECU unit (305) sends the fuel control signal to the gas flow control valve (201) depending on the selected mode. In step 504, if the ECU unit (305) receives an economy mode signal from the switch unit (230) then, in step 506, the fuel control signal is sent to the gas flow control valve (201) to enable sending controlled or precalibrated quantity fuel to the engine. If the ECU unit (305) receives a power mode signal then, in step 505, no fuel control signal is sent to the gas flow control valve (201).
[00019] If the user selects the power mode, then the metering of fuel by gas flow control valve (201) is deactivated. In Power mode, fuel supply is governed only by a conventional gas reducer. The mechanical gas reducer, based on engine speed and load conditions, delivers desired fuel. This system ensures richer mixture preparation at full throttle to achieve rated engine performance. At part throttle conditions, system operates in both stoichiometric and lean conditions. Power mode gives better driveability, but with penalty in fuel economy.
[00020] If the user selects the economy mode, then smart ignition controller (305) activates the gas flow control valve (201). In Economy mode, fuel flow is metered by gas flow control valve (201). The gas flow control valve (201) controls precise fuel quantity based on predefined engine MAP values which is already programmed into the smart ignition controller. Based on engine speed and throttle position signal, gas solenoid position in the gas flow control valve (201) is calibrated in such a way that system operates in lean burn at all throttle position. This mode gives better fuel efficiency with marginal compromise in drive-ability.
[00021] Fig. 5 illustrates a flow chart for an operation of an embodiment of the present invention involving the fuel knob (240). In step 601, an input from the fuel knob is selected by the user. Then in step 602, if the selected input/position of the knob is first position then the fuel supply is shut off. In step 604, if second position is selected and the vehicle enters into the power mode, in step 605. Then in step 606, if the third position is selected then in step 607, the vehicle enters into the economy mode.
[00022] Fig. 6 illustrates a flow chart for an operation of an another embodiment of the present invention involving the switch unit (230). In step, 701, an input option from the switch unit (230) is selected. In step 702, if the liquid fuel mode e.g. petrol mode is selected then in step, 703, the petrol fuel is turned ON and the gas fuel is turned OFF. In step 704, if neutral mode is selected then in step 705, both petrol as well as gas fuel is turned OFF and engine remains in OFF condition. In step 706, if gas power mode is selected then in step 707, the vehicle enters into the power mode with the gas fuel as the main fuel for the vehicle. During the gas power mode, the ECU (305) does not send a fuel control signal (116) to the gas flow valve (201) and the vehicle fuel consumption is dependent on one or more vehicle parameters. In step 708, if the gas economy mode is selected then the vehicle enters into economy mode. In economy mode, the ECU (305) sends a fuel control signal (116) to the gas flow valve (201). This enables in controlling the amount of gas fuel entering into the engine (306) of the vehicle thereby achieving desired fuel efficiency and performance.

LIST OF REFERENCE SIGNS

vehicle (100)
handle bar assembly (106)
front wheel (101)
driver seat assembly (104)
front portion (F)
rear wheels (102)
front fender (103)
housing area (110)
driver seat assembly (104)
gas fuel tank (401)
engine (403)
fuel pressure reducer (200)
dual fuel operation mode switch system (300)
fuel reservoir (307)
primary chamber (205)
secondary chamber (203)
fuel pressure line (304)
ECU unit (305)
Fuel knob(240)