FORM 2
THE PATENTS ACT 1970
(39 of 1970)
AND
The Patents Rules, 2003
COMPLETE SPECIFICATION
(See section 10 and rulel3)
1. TITLE OF THE INVENTION:
"FUEL INJECTION SYSTEM"
2. APPLICANT:
(a) NAME: KPIT Cummins Infosystcms Limited
(b) NATIONALITY: Indian Company incorporated under the
Companies Act, 1956
(c) ADDRESS: 35 & 36 Rajiv Gandhi Infotech Park, Phase 1, MIDC,
Hinjewadi, Pune 411057, Maharashtra, India.
3. PREAMBLE TO THE DESCRIPTION:
The following specification particularly describes the invention and the manner in which it is to be formed.

FIELD OF INVENTION:
The invention generally relates to a fuel injection system for an internal combustion engine. More specifically, it relates to a fuel injection system for injecting gaseous fuels in a controlled manner, causing an appropriate mixing of air & fuel.
BACKGROUND & PRIOR ART:
A fuel injection system is used to supply fuel to an internal combustion engine of a vehicle. The efficiency of injection of fuel by an injection system starts and controls the combustion process. The injection system controls the amount of fuel to be injected into the engine, the time at which fuel is to be injected into the engine and the pattern in which fuel is to be injected into the engine in accordance with the operating conditions of the vehicle.
The fuel injection system supplies the engine with fuel in exact metered quantities and with timed accuracy in proportion to the power requirements of the vehicle. The fuel injection system atomizes the fuel by forcibly pumping it through nozzles under high pressures and ensures that it mixes with sufficient air for complete combustion. The existing fuel injection systems inject the fuel in a liquid spray state into the combustion chamber of the engine. The petroleum based liquid fuels are heavier and hence stays in the manifold path till the time of absorption whereas hydrogen, for example, being lightest escapes in upward direction quickly and hence conventional designs of manifolds are not suitable to retain all supplied volume of gas.
Currently, there are many vehicles existing which use gaseous fuel. They generally use Compressed Natural Gas (CNG). A US Patent No. 5941210 discloses a direct injection system of gaseous fuel for a spark ignited internal combustion engine. Another US Patent No. 4829957 discloses a gaseous fuel injection system for internal combustion engine using a variable pressure controller which translates a varying negative pressure into a proportionately varying amount of gaseous fuel at a positive pressure. This fuel is then injected into engine's air intake system through flow restrictor which co-operate with the

variable pressure controller to provide an amount of fuel proportionate to rate of air flow through engine's air intake system.
Apart from CNG, hydrogen is being sought after to be used as a fuel, since it is comparatively environment friendly.
However, the vehicles using gaseous fuel and especially using hydrogen as a fuel have a disadvantage. As the difference in the viscosity of air and hydrogen is large, in the existing fuel injection systems, during the fuel suction phase hydrogen is sucked more than air into the combustion chamber. As such, the fuel mixture becomes rich and the internal combustion engine loses its fuel efficiency and power. Hence, there is need to develop a system to inject the gaseous fuel in a controlled manner to be mixed with air proportionately.
SUMMARY OF INVENTION:
The present invention discloses a fuel injection system for controlled injection of gaseous fuel which comprises a solenoid plunger, a negative terminal contactor, a mechanical system and plurality non returnable valves (NRV).
Further, the present invention discloses the fuel injection system in which the solenoid plunger is operated either electromechanically or electronically to control the amount of gaseous fuel to be sucked in such that gaseous fuel and air are mixed proportionately.
BRIEF DESCRIPTION OF DRAWINGS:
Fig. 1 illustrates a fuel injection system of the present invention.
DETAILED DESCRIPTION:
The present invention discloses a fuel injection system for injecting fuels in gaseous state in controlled manner comprises a negative terminal contactor to provide pulse width control to solenoid plunger, a solenoid plunger to control the volume of gaseous fuel to be sucked in using pulse width control, a mechanical system for movement of said solenoid

plunger, and a plurality of non-returnable valves (NRV) at the input and output of block piston to allow a unidirectional flow of predetermined volume of gaseous fuel.
In the preferred embodiment, the electromechanical control to the solenoid plunger is provided by the negative terminal contactor, whereas the electronic control to said solenoid plunger is provided by an Electronic Control Unit (ECU).
According to the present invention, the pulse width control is provided by the negative terminal contactor and the width of the pulse is directly proportional to touch area circumference of alternator / cranking rotations. This pulse is provided to the solenoid plunger. The solenoid plunger is pulled in using the mechanical system after the width controlled pulse is received. The depth of solenoid plunger being pulled is dependent on the width of pulse generated. The movement of the solenoid plunger causes controlled / determined volume of gaseous fuel to be passed through the plurality of NRV, situated at input and output side of piston block. The volume of the gaseous fuel to be sucked in is dependent on depth of the solenoid plunger being pulled. The NRVs are used to allow unidirectional flow of gaseous fuel to the block piston.In the fuel injection system according to the present invention, the plurality of NRV consist of an input NRV and an output NRV. The input NRV is situated at the input of block piston whereas the output NRV is situated at the output of block piston.
The mechanical system used for movement for the solenoid plunger in the present invention, consists of a knurled nut being connected to a grooved wheel, a cable and a piston rod. One end of said cable is attached to groove of the grooved wheel such that the grooved wheel is rotated when the cable moves back & forth. The grooved wheel and the knurled nut are attached together and housed in a fixed housing. During upward / downward movement of solenoid plunger, the grooved wheel and knurled nut remain in the same position while rotating horizontally. The piston rod is connected to the solenoid plunger such that said piston rod changes start and end position due to adjustment by knurled nut rotation. Alternately, a width modulated pulse is provided by an Electronic Control Unit (ECU) either independently i.e. in absence of said negative terminal contactor or jointly with said negative terminal contactor.

Referring to Fig. 1, which is a preferred embodiment, an engine block piston (9) is connected to the solenoid plunger (4) through a connecting rod (8). Preferably, hydrogen is used as a gaseous fuel in the fuel injection system described in accordance with the present invention. A pulse width modulation technique is used to control the pull of a solenoid plunger (4). The solenoid plunger (4) is connected to a battery (1) and a negative terminal contractor (3) for pulse width control. The solenoid plunger (4) is pulled in when a modulated pulse of electric supply is provided. The depth that the plunger (4) is pulled in depends on the width and hence magnitude of the electric pulse provided. Also, the pull distance of the solenoid plunger (4) determines the volume of hydrogen to be sucked in. The sucked hydrogen is then pushed into the combustion chamber with the help of mounted springs.
An alternator (2) is connected to the battery (1) and the pulse width control is directly proportional to touch area circumference of alternator (2) i.e. cranking rotations. In many engines, alternators are directly connected to the engine in a one to one proportion. These alternators also act as flywheel. Usually, the body of the engine is negative with respect to its electricity generating system. Some part of the flywheel body is coated with nonconducting material, while the remaining part of the flywheel body non-coated. The non-coated part of the flywheel body is referred to the touch area. While the flywheel is rotating, the circuit with the solenoid plunger (4) will not be completed until the negative terminal contactor (3) does not reach the touch area of the flywheel. Once the touch area of the flywheel comes in contact with negative terminal contactor (3), the circuit is competed and solenoid plunger (4) starts working. The solenoid plunger (4) works till the time it is in contact with the touch area of the flywheel and is hence completing the circuit. Once the circuit is off when the body of the flywheel coated with the nonconducting material comes in contact with the solenoid plunger (4), then the solenoid plunger (4) is pulled back because of the spring action. The on time of the circuit, while the solenoid plunger (4) is in contact with the touch area of the flywheel provides the required pulse width. When the solenoid plunger (4) is in contact with the touch area of the flywheel for a longer period, a longer pulse width is provided and vice versa. Now, when the RPM of the engine is low, the contact time between the solenoid plunger (4) and the touch area of the flywheel will be longer and hence a larger pulse width is provided due to which the engine will receive more fuel for acceleration. Once the

desired RPM is achieved by the engine, the contact time between the solenoid plunger (4) and the flywheel will be shortened, shortening the pulse width provided. Thus, the pulse width and hence the achievable RPM is determined by the circumference of the touch area of the flywheel. An alternator (2) is connected to the battery (1) and the pulse width control is directly proportional to touch area circumference of alternator (2) i.e. cranking rotations. Also, the pulse width provided to the solenoid plunger (4) is dependent on the operating conditions and requirement of the vehicle. The pulse width and hence the volume of hydrogen being injected is controlled based on the engine RPM and cubic capacity of the engine.
An input non-returnable valve (NRV) (6) is used on the gas input at the block piston (9). The injection system injects the determined amount of hydrogen into the block piston (9) with the help of the input NRV (6). This passage of the hydrogen is then blocked so that only air is supplied to the engine from the other open passage and no additional unwanted hydrogen is sucked into the chamber. Thus, the fuel mixture is prevented from becoming rich and the efficiency and power of the engine is retained. Generally, during the start cycle and stop cycle of an IC engine or when the supply of hydrogen gas is short, the fuel mixture tends to become leaner and leaner. Serious flashbacks injections are observed which may enter into the generator of other supply systems resulting into ghost peaks, tailing, loss of sensitivity, etc. The use of NRV valves according to the injection system of the present invention provides for a total cut-off from the supply systems and thus the flashbacks are vented out through other safer passages.
Another non-returnable valve (NRV), i.e. output NRV (7), is used at the output of the block piston (9). The volume of gas input into the inlet manifold is controlled by output NRV (7). The inlet manifold according to the present invention is modified and designed such that a fuel lighter than air, like hydrogen, can easily be transported into the chamber efficiently. An exemplary modification of the inlet manifold is a pipe bent at 90 degrees and having a bore diameter equal to the bore diameter of the manifold portion attached to the vehicle carburetor. The pipe may be made of stainless steel or any other similar material which does not form hydrate or undergo any undesired chemical alteration before and after heating. One end of the manifold pipe is fitted to the combustion chamber at the inlet port of the engine, while hydrogen is injected through the other end

of the pipe which is facing downwards towards the ground. This helps to retain hydrogen inside the inlet manifold as long as the volume is constrained to volume of pipe. The length of the modified manifold maybe approximately 1.5 times of the existing conventional manifold. It is to be noted that the above discussed modification is only an exemplary modification and any such similar modification that help retain hydrogen inside the manifold may be used. Additionally, the NRVs (6, 7) prevent any gas from returning back in the same direction and thus acts as a first stage flashback arrester.
Again referring to Fig. 1, a mechanical system (5) attached to the solenoid plunger (4) and causing the movement of the solenoid plunger (4), consists of a knurled nut connected to a grooved wheel. A cable passes through the groove like a channel. For its movement, one end of the cable is attached to the grooved wheel so that it moves forward and backward as the cable moves. The wheel and nut since attached together and housed in the fixed housing, the knurled plunger elongates in length like a lipstick. The solenoid plunger (4) moves up and down while they both remain in the same position while rotating horizontally. Plunger (4) is connected to the piston rod (8) which changes the start and end position of piston (4) due to upward and downward adjustment by nut rotations. This change in start and end position alters the amount of fuel delivery. This fuel amount in turn controls RPM and torque of the engine.
In another embodiment, a width modulated pulse is provided by an Electronic Control Unit (ECU). The ECU (11) is a unit which is implemented when activation of the solenoid (10) is to be done based on some other intelligence like valve positions, RPM control signals. It functions independently or jointly with flywheel position sensing and/or with the mechanical device in the injection sensing. To operate independently, the ECU (11) delivers the pulse with calculated width and pulse delivery time. All other operations remain same when other two control systems are not in the picture.
In yet another embodiment, a mechanical connection (12) to engine is provided, in which case solenoid plunger (4) or ECU (11) is not needed. Hence, the electromechanical pulse or the Electronic control is no more needed.

We claim,
1. A fuel injection system for injecting fuels in gaseous state in controlled manner
comprises:
a) a negative terminal contactor to provide pulse width control,
b) a solenoid plunger to control the volume of gaseous fuel to be sucked in based on pulse width control,
c) a mechanical system for movement of said solenoid plunger, and
d) plurality of non-returnable valves (NRV) at the input and output of block piston to allow a unidirectional flow of predetermined volume of gaseous fuel.

2. The fuel injection system as claimed in claim 1, wherein electromechanical control to said solenoid plunger is provided by said negative terminal contactor while the electronic control to the said solenoid plunger is provided by an Electronic Control Unit (ECU)
3. The fuel injection system as claimed in claim 1, wherein said pulse width control is provided by said negative terminal contactor and the pulse width is directly proportional to touch area circumference of alternator / cranking rotations.
4. The fuel injection system as claimed in claim 1, wherein depth of solenoid plunger being pulled is dependent on the width of pulse generated and the volume of the said gaseous fuel to be sucked in is dependent on depth of said solenoid plunger being pulled..
5. The fuel injection system as claimed in claim 7, wherein said input NRV is situated at the input of block piston and the said output NRV is situated at the output of the block piston.
6. The fuel injection system as claimed in claim 1, wherein said solenoid plunger is pulled in using said mechanical system after said width controlled pulse is received.

7. The fuel injection system as claimed in claim 2, wherein said mechanical system for movement for said solenoid plunger comprising knurled nut being connected to a grooved wheel, a cable and a piston rod.
8. The fuel injection system as claimed in claim 3, wherein one end of said cable is attached to groove of said grooved wheel such that said grooved wheel is rotated when said cable moves back & forth.
9. The fuel injection system as claimed in claim 3, wherein said piston rod is connected to said solenoid plunger such that said piston rod changes start and end position due to adjustment by knurled nut rotation.
10. The fuel injection system for controlled injection of gaseous fuel as claimed in any of the preceding claim, wherein a width modulated pulse is further provided by an Electronic Control Unit (ECU) either independently i.e. in absence of said negative terminal contactor or jointly with said negative terminal contactor.