Field of Invention
The present invention relates to an electronically controlled gas pressure regulator, particularly, the present relates to reducing the gas storage pressure to a required pressure where the reduction of pressure is controlled by an electronic control unit through high frequency solenoid valve.
Back ground of invention
Now-a-days, alternate fuels are becoming popular in automobiles because of their clean burning and cheaper price. Automotives produces large amount of CO2 through tail pipe emission, which is one of the major cause of global warming. Therefore, all over the world natural gas is accepted as automotive fuel and now original equipment manufacturers are producing vehicles inbuilt with natural gas system.
One of problem for use of the natural gas in automotive application as fuel is in carrying the gas in large quantity with vehicle. To overcome this problem, a gas storage tank has been designed and developed in which gas pressurized up to 250 Bar pressure can stored without changing any physical property of gas molecule. By pressurizing the gas up to 250 bar, a good quantity of gas can be stored in a small container which is required to cover a minimum distance of 150 km by one filling. However, compression of the natural gas up to 250 bar pressure results in a second problem which is reducing the gas pressure from tank pressure to a required injection pressure of engine management system.
Presently, diaphragm type pressure regulators are available which can reduce the gas pressure from the tank pressure to the required pressure through two stages (utilizing two chambers) or 1 stage (utilizing one chamber). Mainly opening and closing of stages/chambers' inlet are controlled by a diaphragm and spring. In such type of pressure regulators, the control of gas flow and gas pressure reduction is operated by the mechanical linkage which has poor response time against the demand.
US Patent No. 7131431B1 discloses the outlet pressure control at three mode of operation static, open loop and close loop. Control of outlet pressure is through a valve which can be a butterfly valve. This pressure regulator required the various inputs like MAT (Manifold Air Temp.), ECT
(Engine Coolant Temp.), Baro (Barometric Pressure), TP (Throttle Position), TIP (Throttle Inlet Pressure) to decide the set pressure in open loop operation.
US Patent No. 6003543 discloses working principle of electronic pressure regulator and its benefit to conventional pressure regulator. It also describes about the variable pressure and increase the dynamic range of electronic pressure regulator. However there is no mention of any control of outlet pressure to maintain the delta pressure across the injector.
International Publication No. WO 2008/125970 A2 discloses opening and closing of an electromagnetic valve to control the fuel from one chamber to another chamber through a disk type of arrangement. To control the outlet pressure, a magnetized valve is used which will act in both the direction.
Conventional pressure regulators have pressure control mechanism which are of mechanical type such as diaphragm and spring whose performance behavior is dependent upon temperature. In other words, when the temperature of engine increases the outlet pressure of regulator decreases which affects the injector performance.
However, conventional pressure regulators have biggest limitation which is they are not able to control outlet pressure within the specified limit in following conditions:
a) When temperature varies from atmospheric to maximum limit;
b) In transient condition or sudden acceleration condition;
c) After 50000 km of running of vehicle;
d) Same unit can not be used for high pressure injection and low pressure injection.
Objects of present invention
The main object of the present invention is to provide a gas pressure regulator.
Another object of the present invention is to provide an electronic gas pressure regulator which
overcomes at least one of the problem of the prior art.
Still another object of the present invention is to provide a novel mechanism which controls
outlet pressure at a pre-set value, maintains the delta pressure constant at all engine operating
condition and can be inbuilt with all modern safety features.
Yet another object of the present invention is to reduce the gas pressure from tank pressure to
required pressure through an electronic gas pressure regulator.
Another object of the present invention is to provide a pressure reducer which controls outlet
pressure variation generated by engine transient condition.
Still another object of the present invention is to provide an electronic gas pressure regulator
which has a fast response time against the demand because the parameters such as flow and
outlet pressure are being controlled by the electronic control unit which is inbuilt with pressure
regulator as an integral part.
Summary of Invention:
The present invention provides an electronic gas pressure regulator (1) to overcome the problem of injector which normally gets stressed during pressure drop at the outlet of regulator in transient and idle operation of the engine. Electronic gas pressure regulator (1) comprises an electronic control unit (ECU) (2) which is configured to receive signals from MAP sensor (Manifold Air Pressure Sensor) (8) to determine the engine demand and react accordingly. Through the MAP signal the electronic control unit (2) controls the delta gas pressure across the injector.
In the electronic gas pressure regulator (1) of the present invention, one or more mechanisms are controlled by electronic control unit (2) which comprises controlling means. Also, in the regulator of the present invention, there is no change in the performance due to the temperature variation.
The electronic gas pressure regulator (1) of the present invention has fast response and also has self diagnostic system to detect the failure.
Further, the electronic gas pressure regulator (1) of the present invention includes less number of components and requires inputs indicative of engine requirements through manifold air pressure
signal (8) which helps the regulator to control the outlet pressure within the desired limit. The main achievement through present invention is to get best performance while involving fewer components. The key control area in present invention is to control high frequency solenoid valve (5) as per demand of gas to engine.
Brief description of the drawings:
Figure 1: A schematic diagram of Electronic gas pressure regulator (1) according to an embodiment of the present invention.
Description of the present invention:
While the invention is susceptible to various modifications and alternative forms, specific embodiment thereof has been shown by way of example in the drawings and will be described in detail below. It should be understood, however that it is not intended to limit the invention to the particular forms disclosed, but on the contrary, the invention is to cover all modifications, equivalents, and alternative falling within the spirit and the scope of the invention as defined by the appended claims.
Before describing in detail embodiments it may be observed that the novelty and inventive step that are in accordance with the present invention resides in an electronic gas pressure regulator. Accordingly, the drawings are showing only those specific details that are pertinent to understanding the embodiments of the present invention so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having benefit of the description herein.
The terms "comprises", "comprising", or any other variations thereof, are intended to cover a non¬exclusive inclusion, such that a setup, device that comprises a list of components does not include only those components but may include other components not expressly listed or inherent to such setup or device. In other words, one or more elements in a system or apparatus proceeded by "comprises... a" does not, without more constraints, preclude the existence of other elements or additional elements in the system or apparatus. The following paragraphs explain present
invention wherein an electronic gas pressure regulator. The invention in respect of the same may be deduced accordingly.
Accordingly, the present invention provides an electronic gas pressure regulator, for a vehicle, comprising a high pressure (HP) chamber (3) receiving gas from a storage tank at high pressure; a low pressure (LP) chamber (4) connected to the HP chamber (3) for receiving the gas therefrom; and a manifold connecting the LP chamber (4) to a gas consumption unit characterized by:
at least one high frequency solenoid valve (5) provided in a gas flow path; and an electronic control unit (ECU) (2) configured to control operation of the said high frequency solenoid valve (5) for controlling the pressure of the gas flow through the manifold to the gas consumption unit.
In one aspect of the present invention, the electronic gas pressure regulator (1) is provided with pressure sensing devices which are located in the pressure chambers and MAP and configured with ECU (2) to send the signals.
Another aspect of the present invention, the LP chamber (4) receives the gas from HP chamber (3) at a required pressure which is equal to the pressure required by gas consumption unit.
Still another aspect of the present invention, the said required pressure in the LP chamber (4) is maintained by the high frequency solenoid valve (5).
Yet another aspect of the present invention, the actuation of high frequency solenoid valve (5) is controlled by ECU (2) with the help of pre-described algorithm/programming.
Further aspect of the present invention, the ECU (2) actuates the high frequency solenoid valve (5) based upon the signal receiving from the pressure sensing devices located in both the chambers or the pressure sensing devices located in MAP.
Furthermore aspect of the present invention, the ECU (2) actuates the high frequency solenoid valve (5) for sudden demand of gas based directly upon the signal receiving from the pressure sensing devices located in MAP.
Another aspect of the present invention, the ECU (2) is provided with failure detection/self diagnostic means to monitor closely the functions of the electronic gas pressure regulator (1).
Accordingly, the present invention provides an electronic gas pressure regulator (1) for controlling the outlet pressure across an injector of an engine of an automotive. In an embodiment of the present invention, the electronic gas pressure regulator (1) comprises two chambers i.e. a high pressure (HP) chamber (2) and a low pressure (LP) chamber (4). Figure 1 shows an electronic pressure regulator (1) according to an embodiment of the present invention.
Referring to figure 1, HP chamber (3) is directly connected with a fuel tank which stores the gas compressed at a high pressure. The HP chamber (3) comprises a pressure sensing device (6). The fuel tank storing the high pressure gas can be located in luggage compartment of vehicle. The pressure regulator of the present invention can be mounted in engine compartment of the vehicle/automotive. The second chamber i.e. LP chamber (4) is connected to gas injector. The LP chamber (4) also has a pressure sensing device (7). The pressure sensing device (7) senses the pressure of the gas coming into the LP chamber (4). The pressure of gas flowing to injector from the LP chamber (4) is equal to the pressure required by the engine. Both the HP and LP chambers are coupled to each other through a circular channel. The flow of gas between the HP chamber (3) and the LP chamber (4) is controlled by a high frequency solenoid valve (5) which is disposed in the said circular channel between the HP chamber (3) and the LP chamber (4). Further, the electronic gas pressure regulator (1) is provided with few safety features which are being described herebelow.
In an embodiment of the present invention, the electronic gas pressure regulator (1) comprises an electronic control unit (ECU) (2). The ECU is configured to receive input signals from pressure sensing devices of HP and LP chambers. The ECU is also configured to receive input signal from manifold air pressure (MAP) sensing device (8) which located in the vehicle for sensing inlet manifold air pressure. The ECU (2) has self diagnostic feature due to which the ECU (2)
checks all sensor signals before start functioning. If the ECU (2) finds any signal out of pre-described limit, the ECU (2) will not start functioning of regulator. Also the ECU (2) will give signal to user.
The HP chamber (3) receives the gas directly from the gas storage tank at a higher pressure. The pressure of the gas senses by the pressure sensing device of the HP chamber (3). The pressure sensing device sends the signal (6) to the ECU (2). Based on the input signals received from the pressure sensing device, the ECU (2) generated output signals for actuating the high frequency solenoid valve (5) to actuate the flow of gas from HP chamber (2) to LP chamber (3). In an embodiment of the present invention, the ECU (2) comprises controlling means and Input/output control. On the basis of input received from sensing devices by the ECU, the controlling means controls the output given to the frequency of high frequency solenoid valve thereby controls the actuation of the solenoid. Further, the pressure sensing device of the LP chamber (4) senses the pressure of gas into the LP chamber (4) and sends the signal (7) for the same to the ECU (2). The supply of gas from HP chamber (3) to LP chamber (4) is continued till the gas pressure of LP chamber (4) reaches to a pressure which is required by the engine. Upon reaching the required pressure of gas in the LP chamber (4), the ECU (2) closes the high frequency solenoid valve (5).
Further, the LP chamber (4) supplies the gas to the gas injector at the said required pressure. The supply of gas from the LP chamber (4) results in pressure drop in the LP chamber (4). This pressure drop senses by the pressure sensing device of the LP chamber and the signal (7) for the same is transmitted to the ECU (2). The ECU (2) again allows the high frequency solenoid valve (5) to open and to supply the gas in the LP chamber (4) till the gas pressure reaches to the required level. Actuation of high frequency solenoid valve (5) increases or decreases the cross sectional area of the circular channel thereby controlling the pressure in second or LP chamber (4) at set or required pressure within the tolerance limit.
Meanwhile, a mechanical spring loaded pressure relief valve is located in the LP chamber (4). If, by any cause, the gas pressure of LP chamber (4) increases two times of the required pressure, then the mechanical spring loaded pressure relief valve opens and releases the excess gas in the atmosphere. This is required for safety of injector.
Accordingly, the electronic gas pressure regulator of the present invention maintains Delta Pressure which is differential pressure between engine Inlet manifold and rail in which low pressure chamber is connected. The injector is mounted at the inlet manifold of the engine and the injector is coupled with the LP chamber (4) of the pressure regulator. In an embodiment of the present invention, inlet of the injector is coupled with the rail in which LP chamber (4) is mounted. Outlet of the injector is coupled with engine inlet manifold. Thereby, the electronic gas pressure regulator (1) of the present invention maintains delta pressure across the injector.
Due to the two chambers (i.e. HP and LP chambers) in the electronic gas pressure regulator, enough quantity of natural gas as reserve to feed during transient or sudden demand can be maintained. In case of sudden demand, the ECU (2) operates the high frequency solenoid valve (5) upon receiving the input signals directly from the pressure sensing device (8) located in the MAP. In order to meet the sudden requirement of excess gas by the engine, the ECU increases the opening time of the high frequency solenoid valve (5) and upon meeting the said requirement, the valve is closed.
The electronic gas pressure regulator (1) of the present invention can be provided with the following safety features:
an electrical solenoid located at inlet of electronic gas pressure regulator (1) which acts as on/off switch for fuel supply. In case of any failure inside the electronic gas pressure regulator (1) detected by either Electronic Control Unit (2) or User, fuel supply at down stream of electronic gas pressure regulator (1) can be stopped.
a mechanical pressure relief device which can be connected to the electronic gas pressure regulator (1) and which can be operated when the fuel pressure increases more than required pressure inside the electronic gas pressure regulator (1). The mechanical pressure relief device can be connected to vent hose through which gas can be vented out in the atmosphere.
- a fuel pressure sensor which be mounted to second chamber or LP chamber (4) of pressure regulator for detecting the small leakages and for stopping the fuel supply through ECU (2) in case of any leakage.
- a failure detection/self diagnostic means can be provided with ECU (2) of the electronic gas pressure regulator (1) for closely monitoring the functions of the pressure regulator. If any component does not function as per the specification a default code can be generated automatically and an indication of the same can be sent to the user.
a cartridge type 12 microns gas filter is mounted inside the electronic gas pressure regulator (1) for filtering natural gas or CNG from dust particles.
a high pressure sensor (9) is also connected to the inlet of the electronic gas pressure regulator (1) to identify the quantity of gas available in the storage tank and monitor any leakage in high pressure line during non operative condition of the engine.
In an embodiment of the present invention, the above safety features can be provided at inlet of the electronic gas pressure regulator (1) i.e. at a location where high pressure tube connects to deliver gas from the tank to HP chamber (3) of the electronic gas pressure regulator (1).
The electronic gas pressure regulator (1) of the present invention maintains a constant delta pressure across the injector which plays most important role during the engine transient operation. Since as natural gas system has biggest safety concern, the electronic gas pressure regulator (1) of the present invention has self diagnostic feature to take action during the failure of any child part of regulator.
Some of the features and advantages of the present invention are mentioned here below:
The present invention includes less number of components and requires inputs of engine requirement through manifold air pressure signal (8) which helps the regulator for controlling the outlet pressure within the desired limit. The biggest achievement through the present invention is to get best performance while involving less number of components. The key control area in the present invention is to control high frequency solenoid valve (5) as per the engine's requirement of gas.
Also, the present invention provides safety to the vehicle and user which is the biggest concern in vehicles operating on alternate fuels.

The present invention is described with reference to the figures and specific embodiments; this description is not meant to be construed in a limiting sense. Various alternate embodiments of the invention will become apparent to persons skilled in the art upon reference to the description of the invention. It is therefore contemplated that such alternative embodiments form part of the present invention.

We claim:
1. An electronic gas pressure regulator (1), for a vehicle, comprising:
a high pressure (HP) chamber (3) receiving gas from a storage tank at high pressure; a low pressure (LP) chamber (4) connected to the HP chamber (3) for receiving the gas therefrom; and a manifold connecting the LP chamber (4) to a gas consumption unit characterized by:
at least one high frequency solenoid valve (5) provided in a gas flow path; and an electronic control unit (ECU) (2) configured to control operation of the said high frequency solenoid valve (5) for controlling the pressure of the gas flow through the manifold to the gas consumption unit.
2. The pressure regulator as claimed in claim 1, wherein the electronic gas pressure regulator (1) is provided with pressure sensing devices which are located in the pressure chambers and MAP and configured with ECU (2) to send the signals.
3. The pressure regulator as claimed in claim 1, wherein the LP chamber (4) receives the gas from HP chamber (3) at a required pressure which is equal to the pressure required by gas consumption unit.
4. The pressure regulator as claimed in claim 1 to 3, wherein the said required pressure in the LP chamber (4) is maintained by the high frequency solenoid valve (5).
5. The pressure regulator as claimed in claim 1, wherein the actuation of high frequency solenoid valve (5) is controlled by ECU (2) with the help of pre-described algorithm/programming.
6. The pressure regulator as claimed in claim 1 to 5, wherein the ECU (2) actuates the high frequency solenoid valve (5) based upon the signal receiving from the pressure sensing devices located in both the chambers or the pressure sensing devices located in MAP.
7. The pressure regulator as claimed in claim 1 to 6, wherein the ECU (2) actuates the high
frequency solenoid valve (5) for sudden demand of gas based directly upon the signal
receiving from the pressure sensing devices located in MAP.
8. The pressure regulator as claimed in claim 1, wherein the ECU (2) is provided with failure detection/self diagnostic means to monitor closely the functions of the electronic gas pressure regulator (1).