FIELD OF THE INVENTION
The present invention relates to the use of- a throttle for gas application in a fuel system. In particular, the present invention relates to the field of use of throttle in the CNG and LPG fuel systems.
BACKGROUND OF THE INVENTION
Due to extensive use of conventional fueled engines (petrol / diesel), the air pollution levels are regularly increasing to a level which is much higher than the permissible limit, thus increasing the pollution to alarming high level causing serious threats and health hazards. This is a matter of great concern. Further the cost of running these engines on conventional fuels i.e. Petrol and Diesel is considerably high. Therefore, the reduction of pollutant emission level and reduction in running cost of fuel have become important issues for which immediate action is considered to be necessary. For both these issues use of CNG or LPG as an alternate fuel has been found to be the only solution. The vehicles powered with 2 Stroke single cylinder or even 4 Stroke single cylinder engines with various engine capacities are basically Spark Ignition (SI) type engines which can use CNG or LPG as a fuel.
At present for carburetor single cylinder engine 3-wheelers using CNG or LPG fuel following types of CNG or LPG Kits are used.
1) CNG or LPG kit with Open Loop System or
2) CNG or LPG Kit with closed loop system
The CNG or LPG kit with closed loop system is comparatively complicated as it involves the use of electronics. Also this system is costlier than open loop system.
In case of open loop system it is difficult to reduce emissions as well as to get the improved fuel economy. It is thus felt to develop a system, which will reduce emission like CO and HC and also improves the fuel economy.
OBJECTIVES OF THE INVENTION
The main object of the present invention is to overcome the disadvantages of the prior art.

Another object of the present invention is to provide a throttle assembly between CNG / LPG regulator and the gas-air mixer.
One more object of the present invention is to provide a throttle assembly that has a simple structural configuration.
Yet another object of the present invention is to provide a throttle assembly that is cost effective.
Still another object of the present invention is to provide throttle assembly that reduces emission of the engine / vehicle.
One more object of the present invention is to provide a throttle assembly that improves fuel economy of such engines.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
The invention will now be explained in detail in relation to the drawings accompanying the complete specification, in which:
FIGURE 1 illustrates a schematic arrangement of the use of a Throttle in accordance
with an embodiment of the present invention; FIGURE 2 illustrates a construction of the Throttle Assembly of the present invention; FIGURE 3 illustrates an alternate location of the Throttle Assembly.
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 and preferred embodiment of the invention and its suggested applications.
The figures and the description hereto are merely illustrative and only exemplify the invention and in no way limit the scope thereof.

Conventionally in case of gaseous fuel system, outlet of gas regulator is directly connected to gas-air mixer through flow control unit (power valve). In Conventional case for deceleration of the vehicle, hydrocarbon emission increases and thereby decreasing the fuel economy.
The function of throttle when placed between gas regulator and gas-air mixer for automotive application in accordance with the present invention will now be explained with reference to FIGURE 1.
FIGURE 1 illustrates a schematic arrangement of use of throttle between gas regulator and gas-air mixer for automotive application, in accordance with one embodiment of the present invention, wherein the numeral 100 generally indicate the system.
The main components of the system illustrated in FIGURE 1 are referenced generally as given below:
a gas regulator 102;
a flow control unit (power valve) 104;
a low pressure hose 106 and 110;
a throttle assembly 108;
a gas-air mixer 112;
an engine 114; and
an accelerator cable 116.
To start the operation of the system, the gas comes out from the cylinder or primary regulator to the gas regulator 102. The flow control unit (power valve) 104 may be integrated at the outlet of the gas regulator 104 or separate. In case of separate power valve, the same is functionally coupled to the gas regulator outlet by means of low-pressure hose. The power valve 104 is functionally coupled to the inlet of the throttle assembly 108 by means of low-pressure hose 106 and the outlet of the throttle assembly is functionally coupled to the gas-air mixer 112 by means of low-pressure hose 110. The lever of the throttle assembly is connected to accelerator by means of the accelerator cable 116.
The main components of the Throttle Assembly 108 as illustrated in FIGURE 2 are referenced generally and given below:

a Throttle Body 202; a Throttle Shaft 204; a Throttle Plate 206; a Lever 208; a Spring 210; an U Seal 212; a Nylon Washer 214; a Circlip 216.
A gas coming out through the flow control unit (power valve) 104 is functionally coupled to the throttle body 202 by means of low-pressure hose 106 and second end of the throttle body 202 functionally coupled to gas-air mixer 112 by means of low-pressure hose 106. The Lever 208, which is directly fitted on Throttle Shaft 204, of the throttle assembly 108 is connected to the accelerator of the vehicle (Not Shown) by means of Accelerator Cable 116.
As the lever of the throttle assembly is connected to the accelerator by means of accelerator cable 116, during acceleration of the engine 114, throttle plate 206 of the throttle assembly 108 will be opened accordingly. During the deceleration of the engine 114, the throttle plate 206 of the throttle assembly 108 will be closed. For the closing action of the throttle plate 206, a spring 210 is provided. This controls the supply of gas to the engine 114 through the gas regulator 102, which controls the emission and also improves the fuel economy. The throttle assembly 108 will act as a variable flow control unit. The location of the throttle assembly 108 is as nearer as possible to the gas-air mixer 112.
The holes are provided to throttle plate 206 for the supply of minimum gas quantity required by engine 114 for the idling when there is zero accelerator position. The U seal 212 and nylon washer 214 is used to avoid leakage of the gas through the throttle assembly 108. To avoid the axial moment of the Throttle Shaft 204, Circlip 216 is optionally used.
The Throttle Assembly is a totally mechanical part. There is no need of any sensor or electronic components in the system. Hence system became cost affective.
According to another aspect of the invention FIGURE 3 illustrates the alternate location of the Throttle Assembly 108 in the system 100. The Throttle Assembly 108 is directly

mounted on the gas-air mixer 112. Here the Throttle Assembly 108 is functionally and directly coupled to the gas-air mixer 112. The low-pressure hose 106 for holding uncontrolled gas is functionally coupled to the gas-air mixer 112 will be eliminated. This gives further precise control of the gas and ultimately better control on emissions.
TECHNICAL ADVANCEMENTS AND ECONOMIC SIGNIFICANCE OF THE INVENTION
The technical advancements offered by the present invention which add to the economic significance of the invention include the realization of:
• The use of throttle located between gas regulator and gas-air mixer for automotive application that has a simple structural configuration;
• The use of throttle located between gas regulator and gas-air mixer for automotive application that is efficient;
• The use of throttle located between gas regulator and gas-air mixer for automotive application that is reliable;
• The use of throttle located between gas regulator and gas-air mixer for automotive application that is cost effective;
• The use of throttle located between gas regulator and gas-air mixer for automotive application reduces emissions; and
• The use of throttle located between gas regulator and gas-air mixer for automotive application improves fuel efficiency of the engine / vehicle.
The numerical values given in respect 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.
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 and scope 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. An improved fuel system for use in vehicles powered with 2 Stroke or 4 Stroke single cylinder basically Spark Ignition (SI) engines with various engine capacities comprising a gas regulator 102; a flow control unit power valve 104; a low pressure hose 106 and 110; a throttle assembly 108; a gas-air mixer 112; an engine 114; an accelerator cable 116 and a throttle wherein said throttle being located between said gas regulator and said gas-air mixer for automotive application.
2. An improved fuel system for use in vehicles powered with 2 Stroke or 4 Stroke single cylinder engine as claimed in claim 1 wherein said engine uses CNG or LPG as fuel.
3. An improved fuel system as claimed in claim 1 or 2 wherein said flow control unit power valve 104 is held integrally or separately at the outlet of said gas regulator 102 or held separately but functionally coupled to the gas regulator outlet by means of low-pressure hose, said power valve 104 is functionally coupled to the inlet of the throttle assembly 108 by means of low-pressure hose 106 and the outlet of the throttle assembly is functionally coupled to the gas-air mixer 112 by means of low-pressure hose 110, lever of said throttle assembly is connected to said accelerator by means of said accelerator cable 116.
4. An improved fuel system as claimed in claim 2 and 3 wherein said throttle Assembly 108 as illustrated in FIGURE 2 comprises a throttle body 202; a throttle shaft 204; a throttle plate 206; a lever 208; a spring 210; an U Seal 212; a nylon washer 214; and optionally a circlip 216.

5. An improved fuel system as claimed in any one of the preceding claims wherein said flow control unit (power valve) 104 is functionally coupled to one end of said throttle body 202 by means of said low-pressure hose 106 and the other end of said throttle body 202 is functionally coupled to said gas-air mixer 112 by means of the low-pressure hose 110, said lever 208 is directly fitted on said throttle shaft 204 of the throttle assembly 108 which is connected to the accelerator of the vehicle (Not Shown) by means of an accelerator cable 116.
6. An improved fuel system as claimed in claim 5 wherein the throttle assembly is connected to the accelerator by means of accelerator cable 116, during acceleration of the engine 114, the throttle plate 206 of the throttle assembly 108 is opened, and during deceleration of the engine 114, the throttle Plate 206 of throttle assembly 108 is closed with the help of a spring 210 as provided which controls the supply of gas to the engine 114 through the gas regulator 102, which controls the emission and the fuel economy.
7. An improved fuel system as claimed in claim 6 wherein said throttle Assembly 108 acts as a variable flow control unit, and is located in close proximity with said gas-air mixer 112.
8. An improved fuel system as claimed in claim 6 wherein holes are provided in said throttle plate 206 for the supply of minimum gas quantity required by the engine 114 for the idling when there is zero accelerator position.
9. An improved fuel system as claimed in claim 8 wherein U seal 212 or nylon
washer 214 is used to avoid leakage of gas through the throttle assembly 108.

10. An improved fuel system as claimed in claim 7 or 8 wherein the Throttle Assembly 108 is directly mounted on the gas-air mixer 112 so that the throttle assembly 108 is functionally and directly coupled to the gas-air mixer 112, the low-pressure hose 106 is used for holding uncontrolled gas is functionally coupled to the gas-air mixer 112 will be eliminated giving a precise control of the gas and ultimately better control on emissions.
11. An improved fuel system as claimed in claim 10 wherein to avoid the axial moment of said throttle shaft 204 a circlip 216 is optionally used.
12. An improved fuel system for use in vehicles powered with 2 Stroke single or 4 Stroke single cylinder engines as claimed in any of the preceding claims wherein single cylinder engine is a 2-wheeler and 3-wheelers using CNG or LPG fuel following types of CNG or LPG Kits are used.
13. An improved fuel system for use in vehicles powered with 2 Stroke single or 4 Stroke single cylinder engines as claimed in claim 12 wherein CNG or LPG kit is an semi - closed loop system