FORM -2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(See section 10 and rule 13)
CNG INJECTION AND IGNITION SYSTEM
VANAZ ENGINEERS LTD.,
an Indian Company of
85/1 ,Paud Road,
Pune-400 038, Maharashtra, India
THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED

FIELD OF THE INVENTION
The present invention relates to the field of fuel injection and ignition systems.
In particular, the present invention relates to the field of CNG injection and ignition systems.
BACKGROUND
Internal combustion engine is an engine in which the combustion of a fuel occurs in the presence of an oxidizer (usually air) in a combustion chamber. Fuel injection systems are used to mix fuel with air in an internal combustion engine. Carburetors have been used for supplying fuel to engines for a long time now. As the automobile industry evolved, carburetors became more and more complicated to handle all the operating requirements. To meet stricter emission requirements, fuel injection systems were devised with the primary objective of determining the necessary amount of fuel and its delivery into the engine using electronic means rather than mechanical means as was seen in the prior art.
Engines are powered by fuels such as petrol, diesel, LPG (Liquefied petroleum gas), CNG (Compressed Natural Gas) and the like. CNG is the most environmentally friendly fuel known today and is increasingly being used as fuel for engines. Besides being the cleanest burning fuel, CNG has several advantages including being more economical, lower maintenance costs for vehicles using CNG and increased life of lubricating oils. Furthermore, CNG is much safer in case of spillage as natural gas is lighter than air, and disperses

quickly when released. Therefore, CNG is becoming the most desirable alternative to petrol and diesel.
Conventionally, in bi-fuel vehicles when petrol is injected into the engine all necessary parameters are controlled by an Engine Management System (EMS) / Electronic Control Unit (ECU) comprising a master and a slave EMS, the master EMS being a part of the engine. The EMS receives signals from various sensors fitted on the engine and monitors the operation of the petrol injector as well as that of the ignition system. When the engine is switched over to gaseous mode, the other EMS called a slave will isolate the petrol injector and receives signal from the master EMS and control the gas injector's operation. However in case of dedicated (single mode) system, the master EMS is not available on the engine. As such the engine has a single EMS that receives signals from sensors directly and controls the ignition as well the gas injection system.
There is thus felt a need for an injection system that is designed specifically for injection of CNG into a single cylinder internal combustion engine. Further, there is a need for an injection system that eliminates contamination of CNG with other fuels and thereby increases efficiency of the system. Furthermore, there is a need for an injection system that has a simple structural configuration.
OBJECTS OF THE INVENTION:
An object of the present invention is to provide a CNG injection and ignition system for injection of CNG into a single cylinder internal combustion engine.
Another object of the present invention is to provide an injection system that eliminates contamination of CNG with other fuels.

Yet another object of the present invention is to provide a CNG injection system that has a simple structural configuration.
Still another object of the present invention is to provide a CNG injection system that is efficient.
One more object of the present invention is to provide a CNG injection system that is reliable.
Still one more object of the present invention is to provide a CNG injection system that is cost effective.
One more object of the present invention is to provide a CNG injection and ignition system for single cylinder engines.
SUMMARY OF THE INVENTION
In accordance with the present invention, there is provided a CNG injection and ignition system for a single cylinder internal combustion engine, comprising: a plurality of sensors adapted to sense engine parameters; an electronic control unit (ECU) adapted to process inputs corresponding to the sensed engine parameters and generate optimized outputs for a desired engine performance; a CNG unit comprising:
a CNG cylinder adapted to store CNG at a high pressure;
a CNG cylinder valve mounted directly on the CNG cylinder;
a CNG filling unit functionally coupled to the CNG cylinder;
a solenoid valve functionally coupled to the CNG cylinder; the
valve adapted to regulate the flow of CNG from the CNG cylinder

to the engine and further adapted to restrict the flow of CNG when
the engine is not running;
a pressure gauge functionally coupled to the CNG cylinder; the
pressure gauge adapted to indicate the pressure of CNG contained
inside the CNG cylinder;
a CNG regulator functionally coupled to the solenoid valve; the
CNG regulator adapted to regulate the pressure of the CNG
entering into the engine; and
a CNG filter functionally coupled to the CNG regulator; the filter
adapted to remove impurities from C^G and provide a filtered
CNG; a gas injector adapted to inject the filtered CNG into an intake manifold of the engine; and
a spark plug powered by an ignition coil, the spark plug adapted to provide a spark for the ignition.
Preferably, in accordance with this invention, the plurality of sensors
comprises:
a crankshaft speed/position sensor functionally coupled to the engine; the
crankshaft speed sensor adapted to sense the number of revolutions of the
engine;
a camshaft speed/position sensor functionally coupled to the engine; the
camshaft speed sensor adapted to verify the position of a top dead center
(TDC) of the piston of the engine;
a lambda sensor / oxygen sensor disposed in the exhaust portion of the
engine; the oxygen sensor adapted to sense the percentage of oxygen

present in the exhaust gases and generate a voltage output corresponding
to the sensed percentage of oxygen;
an intake air temperature sensor functionally coupled to the engine; the
intake air temperature sensor adapted to detect temperature of air entering
into the engine;
a pedal position/ throttle position sensor adapted to detect load on the
engine;
a manifold absolute pressure and temperature sensor adapted to detect the
intake air temperature into the engine;
a coolant temperature sensor adapted to measure the temperature of the
coolant entering into the engine; and
a CNG temperature and pressure sensor adapted to detect CNG
temperature and pressure.
Optionally, the pressure gauge is provided with a level indicator.
Typically, in accordance with the present invention, the pressure gauge is an analog meter.
In accordance with one embodiment of the present invention, the CNG regulator is adapted to reduce the pressure of the CNG from 200 bar to 2 bar.
Preferably, in accordance with this invention, the electronic control unit (ECU) is adapted to provide the outputs to ignition coil drivers, solenoid valve drivers and injector drivers for activation of the ignition coil, the solenoid valve and the gas injector respectively.
Additionally, in accordance with this invention, the electronic control unit (ECU) is adapted to control a radiator fan based on sensed radiator coolant temperature

and control the operation of a starter motor relay to avoid damage of starter motor due to a long period of engine cranking. The electronic control unit (ECU) is further adapted to monitor the voltage of a battery for proper functioning of the electronic components of the system.
Preferably, in accordance with this invention, the electronic control unit (ECU) is adapted to be calibrated by connection to at least one of a computer or a calibration tool to modify the engine parameters.
BRIEF DESCRIPTION OF ACCOMPANYING DRAWINGS
The invention will now be explained in relation to the accompanying drawings, in which:
FIGURE 1 illustrates a schematic arrangement of a CNG injection and ignition system in accordance with an embodiment of the present invention;
FIGURE 2 illustrates a schematic representation of an engine of the CNG injection and ignition system of FIGURE 1; and
FIGURE 3 illustrates a schematic representation of an electronic control unit (ECU)/ engine control module (ECM) of the engine of FIGURE 2 indicating typical inputs to and outputs from the ECU.
DETAILED DESCRIPTION OF ACCOMPANYING DRAWINGS
The invention will now be described with reference to the embodiment shown in the accompanying drawings. The embodiment does not limit the scope and

ambit of the invention. The description relates purely to the exemplary preferred embodiment of the invention and its suggested applications.
Conventional fuel injection systems are designed for multi cylinder engines and are not specifically designed for CNG resulting in contamination of CNG with other fuels and making the system less efficient. The CNG injection system in accordance with the present invention aims to overcome these drawbacks of the prior art and also satisfy future emission norms such as BS-IV and the like.
The CNG injection system in accordance with the present invention will now be explained with reference to FIGURES 1 to 3.
FIGURE 1 illustrates a schematic arrangement of a CNG injection and ignition system, in accordance with one embodiment of the present invention, wherein the CNG injection and ignition system is generally indicated by the numeral 100.
FIGURE 2 illustrates a schematic representation of an engine of the CNG injection system of FIGURE 1 and FIGURE 3 illustrates a schematic representation of an electronic control unit (ECU)/ engine control module (ECM) of the engine of FIGURE 2.
The main components comprising the present invention along with the associated components illustrated in FIGURE 1, FIGURE 2 and FIGURE 3 are referenced generally as given below:
- a CNG cylinder 102;
- a CNG cylinder valve 104;
- a CNG filling unit 106;

- a solenoid valve 108;
- a pressure gauge 110 (with/without a level indicator means 132);
- a CNG regulator 112;
- a CNG filter 114;
- an electronic control unit (ECU) 116 (illustrated in FIGURE 3);
- a gas injector 118;
- a crankshaft speed/position sensor 120;
- a camshaft speed/position sensor 122;
- a lambda sensor / oxygen sensor 124;
- an intake air temperature sensor (not shown);
- a pedal position/ throttle position sensor 128 (illustrated in FIGURE 3);
- an internal combustion engine 130;
- a manifold absolute pressure and temperature sensor 134;
- a spark plug 136;
- a coolant temperature sensor / engine body temperature sensor 138;
- an engine exhaust 140;
- an ignition coil 142;
- a battery 144 (illustrated in FIGURE 3);
- a vehicle speed sensor 146 (optional) (illustrated in FIGURE 3);
- a charger 148 (illustrated in FIGURE 3);
- a CNG temperature and pressure sensor 150 (illustrated in FIGURE 3);
- an alternator 152 (illustrated in FIGURE 3);
- an ignition switch 154 (illustrated in FIGURE 3);
- a fan relay 156 (illustrated in FIGURE 3);
- a malfunction indication lamp 158 (illustrated in FIGURE 3);
- an 02 heater 160 (illustrated in FIGURE 3);
- a control relay 162 (illustrated in FIGURE 3); and

- a throttle / idle stepper control (illustrated in FIGURE 3).
A CNG unit referred to in the description herein below comprises the CNG cylinder 102; the CNG cylinder valve 104; the CNG filling unit 106; the solenoid valve 108; the pressure gauge 110; the CNG regulator 112; and the CNG filter 114.
The CNG cylinder 102 stores CNG at high pressure. The CNG cylinder valve 104 is mounted directly on the CNG cylinder 102. The CNG cylinder valve 104 facilitates opening and closing of the outlet of the CNG cylinder 102. The CNG filling unit 106 is functionally coupled to the CNG cylinder 102 for fuelling and re-fuelling of the CNG cylinder 102. Fuelling and re-fuelling is carried out at various locations such as filling stations, cascades, and the like.
The solenoid valve 108 is functionally coupled to the CNG cylinder 102 to regulate the flow of CNG from the CNG cylinder 102 to the internal combustion engine 130. More specifically, the solenoid valve 108 restricts flow of CNG when the engine 130 is not running. The solenoid valve 108 is an automatic On/Off valve. The pressure gauge 110 is functionally coupled to the CNG cylinder 102 to indicate the pressure of CNG contained inside the CNG cylinder 102. The pressure gauge 110 includes a level indicator means 132 for indicating the value of the pressure of CNG contained inside the CNG cylinder 102. However, the pressure gauge 110 is not limited to any particular type. In accordance with another embodiment of the present invention, the pressure gauge 110 is an analog meter to indicate the pressure of CNG contained inside the CNG cylinder 102.

The CNG regulator 112 is functionally coupled to the solenoid valve 108 to regulate the pressure of CNG entering into the engine 130. In accordance with the present invention, the CNG regulator 112 varies the outlet pressure from 1 bar to 8 bar as per requirement. In accordance with another embodiment of the present invention, the CNG regulator 112 is adapted to reduce the pressure of CNG from 200 bar to 2 bar. The CNG filter 114 is functionally coupled to the CNG regulator 112 to remove impurities from CNG flowing through the CNG injection system 100. This helps in preventing malfunction of the gas injector 118 due to impurities contained in the CNG. Thus, filtered CNG enters into the gas injector 118.
The gas injector 118 injects filtered CNG into an intake manifold of the engine 130. The crankshaft speed/position sensor 120 (illustrated in FIGURE 2) is functionally coupled to the engine 130 and the ECU 116 (illustrated in FIGURE 3). The crankshaft speed/position sensor 120 senses the revolutions of the engine 130. In accordance with another embodiment of the present invention, the crankshaft speed/position sensor 120 measures the revolutions of the crankshaft. The camshaft speed/position sensor 122 (illustrated in FIGURE 2) is functionally coupled to the engine 130 and the ECU 116. The camshaft speed/position sensor 122 verifies the position of the top dead centre (TDC) of the engine piston. The position of the top dead center of the engine facilitates in identifying the suction stroke of the engine for deciding the time of injection of the CNG into the engine 130. In case of single cylinder engine, the position of the TDC can also be decided by using an engine crank shaft censor.
The lambda sensor / oxygen sensor 124 (illustrated in FIGURE 3) is disposed in the exhaust portion of the engine 130. The lambda sensor 124 senses the

percentage of oxygen present in the exhaust gases. Furthermore, the lambda sensor 124 also provides information regarding the percentage of oxygen present in the exhaust gases to the ECU 116. In accordance with the present invention, the information provided by the lambda sensor 124 to the ECU 116 is in the form of a voltage output. The ECU 116 designates a particular lambda value for a particular value of percentage of oxygen present in the exhaust gases.
The intake air temperature sensor (not shown) is functionally coupled to the engine 130 and the ECU 116 to detect temperature of air entering into the engine 130. Accordingly, the intake air temperature facilitates the ECU 116 to calculate the total volume of air and CNG to be injected in the engine 130, as the density of the intake air depends upon the temperature of the intake air. More specifically, the temperature of the intake air entering into the engine 130 facilitates the ECU 116 to decide the amount of CNG to be injected into the engine 130. In accordance with another embodiment of the present invention, the intake air temperature is decided by using the manifold absolute pressure and temperature sensor 134.
The pedal position / throttle position sensor 128 (illustrated in FIGURE 3) is functionally coupled to the ECU 116 for detection of load on the engine 130. The pedal position / throttle position sensor 128 facilitates the ECU 116 to decide a throttle opening position based on the output from the pedal position / throttle position sensor 128. More specifically, as load on the engine 130 increases, the ECU 116 facilitates more opening of the throttle valve.
The engine 130 further includes a spark plug 136 (illustrated in FIGURE 1), a coolant temperature sensor / engine body temperature sensor 138 (illustrated in

FIGURE 2), an engine exhaust 140 (illustrated in FIGURE 1) and a throttle assembly 156 (illustrated in FIGURE 1). The spark plug 136 is adapted to provide a spark for ignition of the CNG and the air mixture. The spark plug 136 is powered by an ignition coil 142. The operations of the ignition coil 142 (spark timing and period) are controlled by the ECU 116. The coolant temperature sensor / engine body temperature sensor 138 measures the temperature of the coolant entering into the engine 130. The coolant enters into the engine 130 through a radiator. The flow of the coolant from the radiator to the engine 130 is indicated by an arrow referenced as 'A' in FIGURE 2. The engine exhaust 140 is provided for emitting combustion gases from the engine 130.
Referring to FIGURE 3, a schematic representation of the ECU 116 is depicted. The electronic control unit (ECU) 116 is also referred to as an Engine Control Module (ECM). The ECU 116 calculates the CNG injection timing, spark timing and injection period based on the input signals received from all type of sensors used in the CNG injection system 100. The ECU 116 includes a processing unit (not shown) to process inputs in relation to engine speed. crankshaft speed or crankshaft position, coolant temperature, pedal position or throttle position, manifold absolute pressure and temperature, barometric pressure, lambda value, battery voltage, gas temperature and pressure, and engine oil temperature. The ECU 116 obtains inputs in relation to camshaft speed/position and the air intake temperature, respectively from the camshaft speed or position sensor 122 and the air intake temperature sensor. The pressure in the CNG cylinder 102 is detected by a gas tank pressure and temperature sensor (not specifically indicated). The engine oil temperature is detected by an engine oil sensor (not specifically indicated). The CNG temperature and

pressure is detected by a CNG temperature and pressure sensor 150. A vehicle speed sensor 146 is optionally provided to sense speed of the vehicle.
After getting inputs from all above sensors, the ECU 116 provides output signals to ignition coil drivers, solenoid valve drivers and injector drivers for activation of the ignition coil 142, the solenoid valve 108, the throttle / idle stepper control 164 and the gas injector 118 respectively. Further, by connecting the ECU 116 to a computer or by using a calibration tool, the user can modify the parameters for the optimization of the engine 130 to achieve desired performance. The optimization parameters depend on the engine capacity and the engine design.
The ECU 116 also controls the operation of the following relays based on engine parameters:
1) engine radiator fan relay 156 : Based on the radiator coolant temperature, the radiator fan is turned ON / OFF through the ECU 116; and
2) starter Motor relay / control relay 162: To avoid damage of a starter motor due to a long period of engine cranking, the ECU 116 controls of the operation of the starter motor.
The malfunction indication lamp 158 is provided to indicate any malfunction in the operation of the system in accordance with the present invention.
Furthermore, in accordance with the present invention, a piping means, such as a high pressure rigid pipe or a high pressure flexible pipe, is used to connect various components of the CNG injection system 100 to each other and to

transfer the CNG from one component to another. Also, all electronic components of the CNG injection system 100 are operated by the battery 144. The battery 144 co-operates with the charger 148 and the alternator 152 and is functionally connected to the ECU 116 and an ignition switch 154. The ignition switch 154 is used for activation and deactivation of the ignition coil 142. Accordingly, the ECU 116 of the CNG injection system 100 monitors the voltage of the battery 144 for proper functioning of the electronic components of the CNG injection system 100.
TECHNICAL ADVANCEMENTS AND ECONOMIC SIGNIFICANCE
The technical advancements offered by the present invention which add to the economic significance of the invention include the realization of:
• an injection system dedicated for injection and ignition of CNG into a single cylinder internal combustion engine;
• an injection system that eliminates contamination of CNG with other fuels;
• a CNG injection system that has a simple structural configuration;
• a CNG injection system that is efficient;
• a CNG injection system that is reliable;
• a CNG injection system that is cost effective;
• a CNG injection system for single cylinder engines; and

• an ECU that controls injection as well as ignition system of the single cylinder engine.
The numerical values given of various physical parameters, dimensions and quantities are only approximate values and it is envisaged that the values higher or lower than the numerical value assigned to the physical parameters, dimensions and quantities fall within the scope of the invention and the claims unless there is a statement in the specification to the contrary.
Wherever a range of values is specified, a value up to 10% below and above the lowest and highest numerical value respectively, of the specified range, is included in the scope of the invention.
While considerable emphasis has been placed herein on the specific features of the preferred embodiment, it will be appreciated that many additional features can be added and that many changes can be made in the preferred embodiment without departing from the principles of the invention. These and other changes in the preferred embodiment of the invention will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the invention and not as a limitation.

We Claim:
1. A CNG injection and ignition system for a single cylinder internal combustion engine, comprising:
a plurality of sensors adapted to sense engine parameters;
an electronic control unit (ECU) adapted to process inputs
corresponding to the sensed engine parameters and generate
optimized outputs for a desired engine performance;
a CNG unit comprising:
a CNG cylinder adapted to store CNG at a high pressure;
a CNG cylinder valve mounted directly on the CNG
cylinder;
a CNG filling unit functionally coupled to the CNG
cylinder;
a solenoid valve functionally coupled to the CNG cylinder;
said valve adapted to regulate the flow of CNG from the
CNG cylinder to the engine and further adapted to restrict
the flow of CNG when the engine is not running;
a pressure gauge functionally coupled to the CNG cylinder;
said pressure gauge adapted to indicate the pressure of CNG
contained inside the CNG cylinder;
a CNG regulator functionally coupled to the solenoid valve;
said CNG regulator adapted to regulate the pressure of the
CNG entering into the engine; and
a CNG filter functionally coupled to the CNG regulator; said
filter adapted to remove impurities from CNG and provide a
filtered CNG;

a gas injector adapted to inject the filtered CNG into an intake manifold of the engine; and
a spark plug powered by an ignition coil, said spark plug adapted to provide a spark for the ignition.
2. The CNG injection and ignition system as claimed in claim 1, wherein said plurality of sensors comprises:
a crankshaft speed/position sensor functionally coupled to the
engine; said crankshaft speed sensor adapted to sense the number
of revolutions of the engine;
a camshaft speed/position sensor functionally coupled to the
engine; said camshaft speed sensor adapted to verify the position
of a top dead center (TDC) of the piston of the engine;
a lambda sensor / oxygen sensor disposed in the exhaust portion of
the engine; said oxygen sensor adapted to sense the percentage of
oxygen present in the exhaust gases and generate a voltage output
corresponding to the sensed percentage of oxygen;
an intake air temperature sensor functionally coupled to the engine;
said intake air temperature sensor adapted to detect temperature of
air entering into the engine;
a pedal position/ throttle position sensor adapted to detect load on
the engine;
a manifold absolute pressure and temperature sensor adapted to
detect the intake air temperature into the engine;
a coolant temperature sensor adapted to measure the temperature
of the coolant entering into the engine; and

a CNG temperature and pressure sensor adapted to detect CNG temperature and pressure.
3. The CNG injection and ignition system as claimed in claim 1, wherein the pressure gauge is provided with a level indicator.
4. The CNG injection and ignition system as claimed in claim 1, wherein the pressure gauge is an analog meter.
5. The CNG injection and ignition system as claimed in claim 1, wherein the CNG regulator is adapted to reduce the pressure of the CNG from 200 bar to 2 bar.
6. The CNG injection and ignition system as claimed in claim 1, wherein said electronic control unit (ECU) is adapted to provide said outputs to ignition coil drivers, solenoid valve drivers and injector drivers for activation of the ignition coil, the solenoid valve and the gas injector respectively.
7. The CNG injection and ignition system as claimed in claim 1, wherein said electronic control unit (ECU) is adapted to control a radiator fan based on sensed radiator coolant temperature.
8. The CNG injection and ignition system as claimed in claim 1, wherein said electronic control unit (ECU) is adapted to control the operation of a starter motor relay to avoid damage of starter motor due to a long period of engine cranking.

9. The CNG injection and ignition system as claimed in claim 1, wherein said electronic control unit (ECU) is adapted to monitor the voltage of a battery for proper functioning of the electronic components of said system.
10. The CNG injection and ignition system as claimed in claim 1, wherein said electronic control unit (ECU) is adapted to be calibrated by connection to at least one of a computer or a calibration tool to modify the engine parameters.