Description:PRECISION CONTROL TWO-STAGE CNG PRESSURE REGULATOR WITH MULTI FEATURES
Field of the invention
The present invention generally relates to automobiles having air/water-cooled internal combustion engines that uses CNG as a fuel and more particularly it relates to CNG pressure regulator used in automobiles having air/water-cooled internal combustion engines using CNG as fuel.

Background of the invention
The pollution control drive initiated across the globe provides a boost to the use of CNG-operated appliances and vehicles. One of the major sectors contributing to pollution is the automotive sector, the vehicles run on diesel and petrol as fuel. These vehicles contribute to pollution through brake pollution, tire pollution, particle pollution, and toxic emission from engines, etc. In order to address these issues, a solution in the form of CNG as fuel is the only way.
A CNG supply system includes a pressure regulator. The pressure regulator is a pressure-reducing valve that controls the pressure of a fluid or gas to the desired value using negative feedback from the controlled pressure. Regulators are used for allowing high-pressure fluid supply lines or cylinders to be reduced to safe and/or usable pressures for various applications. A single-stage gas pressure regulator reduces cylinder pressure to delivery or outlet pressure in one step. The prior patent application 2905/MUM/2010 disclosed a diaphragm-operated single-stage CNG pressure regulator. Referring to Figure 1, the single-stage regulator (201) is directly mounted on the CNG cylinder valve (145). The diaphragm-operated single-stage regulator includes a diaphragm that is loaded using a spring and adjusted by an adjusting screw. The safety relief valve of the regulator releases the pressure when the outlet pressure exceeds 1.5 times of the set pressure of CNG. The diaphragm-operated single-stage CNG pressure regulator reduces the cylinder pressure of 200 bars to the required pressure by means of adjusting the screw. However, there is an exponential decrease in the cylinder pressure of the CNG due to the consumption of CNG to run the engine. Due to such a high reduction in the inlet pressure, the outlet pressure of this single-stage pressure regulator fluctuates considerably. Thus there is a need for a system to deliver a steady flow pressure for downstream appliances.
Further, the CNG pressure in a cylinder is high when the CNG cylinder is fully filled. During vehicle use, the CNG pressure drops continuously as the engine consumes the CNG. The drop in CNG cylinder pressure affects the outlet pressure of the single-stage pressure regulator. Thus, it is difficult to maintain a constant and stable CNG pressure supply to the gas injector using a single-stage pressure regulator.
Furthermore, the BSVI emission norms have been implemented throughout the country and to meet these BSVI emission norms, it is essential to control the CNG pressure supply to the injector of the CNG fuel system to reduce the pollutant from the engine exhaust.
Accordingly, there exists a need for a system that overcomes the drawbacks of prior art techniques.
Objects of the invention
An object of the present invention is to supply controlled CNG pressure flow to the injector.
Another object of the present invention is to provide stable CNG pressure regulating system.
Yet another object of the present invention is to eliminate steel tubing and component joints, to reduce the cost and increase safety.
Yet another object of the present invention is to increase vehicle safety during CNG refilling.
Yet another object of the present invention is to reduce the CNG pressure to the user’s desired level in two stages.
Summary of the Invention
The present invention provides a precision control two-stage CNG pressure regulator with multi features receiving CNG from a CNG cylinder through a refueling unit and supplying CNG to a vehicle engine through a filter solenoid valve. The refueling unit includes a refueling adapter, a dust plug, a non-return valve, and a filter sub-assembly. The precision control two-stage CNG pressure regulator is coupled to the refueling unit with a bullnose connector in a sealing manner. The precision control two-stage gas pressure regulator comprises a regulator first stage and a regulator second stage. The regulator's first stage receives CNG through a first-stage inlet orifice at a set pressure from the refueling unit. The regulator's first stage is having a spring-loaded first-stage diaphragm clamped between a first-stage bonnet and a first-stage body, flexing upwards and downwards due to CNG pressure variations inside the first-stage body. A lever and a first-stage pad arrangement are operably connected to the spring-loaded first-stage diaphragm for partial opening and closing of the first-stage orifice in response to the flexing movement of the spring-loaded first-stage diaphragm. The regulator's second stage is coupled to the regulator's first stage receiving CNG through a second-stage inlet orifice from the regulator's first stage. The second stage inlet orifice is the outlet of the regulator's first stage. The regulator's second stage is having a spring-loaded second-stage diaphragm clamped between a second-stage bonnet and a second-stage body. The spring-loaded second-stage diaphragm flexes upwards and downwards due to CNG pressure variations inside the second-stage body. A spindle and a second stage pad arrangement are operably connected to the spring-loaded second diaphragm for partial opening and closing of the second stage inlet orifice in response to the flexing movement of the spring-loaded second stage diaphragm. The outlet pressure of the regulator's first stage is factory set while the outlet pressure of the regulator's second stage is set to a desired pressure using an adjustment screw, wherein a spring load on the second stage diaphragm is adjusted by rotating the adjustment screw. Fluctuation in CNG pressure during vehicle use is controlled in two stages by opening and closing the first stage inlet orifice and the second stage inlet orifice till the set pressure is maintained inside the first stage body and the second stage body.
Brief description of the drawings
The embodiments can be better understood with reference to the following drawings and descriptions. The components in the figures are not necessarily to scale, the emphasis instead being placed upon illustrating the principles of the embodiments. Moreover, the figures, like reference numerals designate corresponding parts throughout the different views.
Reference will be made to embodiments of the invention, examples of which may be illustrated in the accompanying figures. These figures are intended to be illustrative, not limiting. Although the invention is generally described in the context of these embodiments, it should be understood that it is not intended to limit the scope of the invention to these particular embodiments.
The above and other objects, features, and advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, which:
Figure 1 illustrates a schematic diagram of the diaphragm-operated CNG pressure regulator in accordance with the prior art;
Figure 2 illustrates a schematic diagram of precision control and diaphragm-operated two-stage CNG pressure regulator with multi-features, in accordance with the present invention;
Figure 3 illustrates a sectional view of precision control and diaphragm operated two-stage CNG pressure regulator with multi-features, in accordance with the present invention;
Figure 3(C) depicts section C of the precision control and diaphragm-operated two-stage CNG pressure regulator with multi-features of Figure 3;
Figure 3(D) depicts section D of the precision control and diaphragm-operated two-stage CNG pressure regulator with multi-features of Figure 3;
Figure 3(E) depicts section E of the precision control and diaphragm-operated two stage CNG pressure regulator with multi-features of Figure 3; and
Figure 4 shows a graphical representation of table 2 of the execution report of the precision control two stage pressure regulator with multi features of the present invention & single stage pressure regulator of the Prior Art.
DETAILED DESCRIPTION OF THE INVENTION
The present invention is a system which is a mechanical system consisting of a mechanical assembly constituting operative mechanism and pathways for passage and for accurate, customized supply of CNG and CNG Pressure Regulation units for controlling the actuation of various mechanical components constituting the actuating and controlling CNG regulation components to perform their associative function for executing the method steps thereof of the system for accurate, customized supply of CNG in a controlled and precise manner.
In the following description, for the purpose of explanation, specific details are set forth in order to provide an understanding of the present invention. It will be apparent, however, to one skilled in the art that the present invention may be practiced without these details. One skilled in the art will recognize that embodiments of the present invention, some of which are described below, may be incorporated into a number of systems.
The various embodiments of the present invention provide a system for controlling CNG cylinder pressure in two stages that assists in accurate, customized supply of CNG to the injector as per requirement.
Furthermore, connections between components and/or modules within the figures are not intended to be limited to direct connections. Rather, these components and modules may be modified, re-formatted or otherwise changed by intermediary components and modules.
The systems/devices described herein are explained using examples with specific details for better understanding. However, the disclosed embodiments can be worked on by a person skilled in the art without the use of these specific details.
Throughout this application, with respect to all reasonable derivatives of such terms, and unless otherwise specified (and/or unless the particular context clearly dictates otherwise), each usage of:
“a” or “an” is meant to read as “at least one.”
“the” is meant to be read as “the at least one.”
References in the present invention to “one embodiment” or “an embodiment” mean that a particular feature, structure, characteristic, or function described in connection with the embodiment is included in at least one embodiment of the invention. The appearances of the phrase “in one embodiment” in various places in the specification are not necessarily all referring to the same embodiment.
If the specification states a component or feature "may”, “can", "could", or "might" be included or have a characteristic, that particular component or feature is not required to be included or have the characteristic.
As used in the description herein and throughout the claims that follow, the meaning of “a”, “an” and "the" includes plural reference unless the context clearly dictates otherwise. Also, as used in the description herein, the meaning of "in" includes "in" and "on" unless the context clearly dictates otherwise.
Exemplary embodiments will now be described more fully hereinafter with reference to the accompanying drawings, in which exemplary embodiments are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. These embodiments are provided so that this invention will be thorough and complete and will fully convey the scope of the invention to those of ordinary skill in the art. Moreover, all statements herein reciting embodiments of the invention, as well as specific examples thereof, are intended to encompass both structural and functional equivalents thereof. Additionally, it is intended that such equivalents include both currently known equivalents as well as equivalents developed in the future (i.e., any elements developed that perform the same function, regardless of structure).
Hereinafter, embodiments will be described in detail. For clarity of the description, known constructions and functions will be omitted. Parts of the description may be presented in terms of operations performed by a mechanical system, using terms such as safety relief valve, spring, screw, gauge, and the like, consistent with the manner commonly employed by those skilled in the art to convey the substance of their work to others skilled in the art.
While embodiments of the present invention have been illustrated and described, it will be clear that the invention is not limited to these embodiments only. Numerous modifications, changes, variations, substitutions, and equivalents will be apparent to those skilled in the art, without departing from the spirit and scope of the invention, as described in the claim.
The system of the present invention provides a precision control and diaphragm-operated two-stage CNG pressure regulator with multi features that precisely control the CNG pressure in two stages at the outlet of the regulator. Thus, the present precision control diaphragm-operated two-stage CNG pressure regulator maintains a constant required flow and stable pressure to the vehicles at a lower cost with higher functionalities.
The present invention is illustrated with reference to the accompanying drawings, throughout which reference numbers indicate corresponding parts in the various figures. These reference numbers are shown in brackets in the following description. Table 1 enlists the reference numerals and corresponding components:
Table 1
Ref. no. Component Ref. no. Component
101 Two-stage CNG regulator 124 Second safety relief valve
102 Refueling adaptor 125 First stage diaphragm
103 Dust plug 126 --
104 NRV sub-assembly 127 Lever
105 String 128 First stage pad
106 Mounting plate 129 Spindle
107 Micro switch 130 Second stage pad
108 First Screw 131 SRV spring
109 Second screw 132 SRV pad
110 Filter sub-assembly 133 SRV adjusting screw
111 Pressure gauge 134 First stage bonnet
112 Junction block 135 First stage inlet orifice
113 Lock nut 136 Seat
114 Coupling screw 138 Second stage inlet orifice
115 Bull nose connector S1 Regulator first stage
116 O-ring S2 Regulator second stage
117 Second stage bonnet 141 Injector
117A Second stage body 142 Low pressure flexible hose
118 Second stage spring 143 Filter solenoid valve
119 Second stage diaphragm 144 Low pressure flexible hose
120 First stage body 145 Hand wheel valve
121 First safety relief valve 146 CNG cylinder
122 First stage spring 201 Single stage regulator
123 Adjusting screw

Referring to figures 2 to 4, a CNG pressure regulating system (100), having a precision control two-stage CNG pressure regulator (101) with multi features incorporated for maintaining a constant and stable CNG pressure supply to a gas injector (141), is shown in accordance with the present invention.
Figure 2 illustrates a schematic view of the CNG pressure regulating system (100) (hereinafter referred as ‘the system (100)’); and figure 3 illustrates a sectional view of a precision control diaphragm operated two-stage CNG regulator (101) with multi features, (hereinafter referred as ‘the two-stage regulator (101)’) connected with a bull nose connector (115) and a pressure gauge (111). Figure 3(C), 3(D) and 3 (E) illustrate sections C, D and E of the two-stage pressure regulator (101) of Figure 3, in accordance with the present invention.
Referring to Figure 2, a CNG cylinder (146) stores CNG at high pressure of 200 bar. By rotating a hand wheel of a hand wheel valve (145) mounted rigidly on the CNG cylinder (146), the supply of CNG to the downstream system can be started or stopped. The two-stage regulator (101) is coupled with a filter solenoid valve (143) by a low-pressure flexible hose (144) and the filter solenoid valve outlet port is coupled to an injector (141) and to an engine respectively. The filter solenoid valve (143) is used in the system (100) for safety features after the two-stage regulator (101) and for delivering the clean, neat, and dust free CNG gas to the injector (141). The two-stage pressure regulator (101) is directly fitted on the hand wheel valve (145) using a Bull nose connector (115) and a coupling screw (114). The two stage pressure regulator (101) directly fitted to the outlet of the hand wheel valve (145) reduces the 200 Bar CNG pressure from the cylinder to the desired outlet pressure which is low pressure. This eliminates the use of high-pressure steel tubes and also reduced lot many high-pressure (200 bar) joints. This makes the system safer. To avoid leakage through the bull nose connector (115), an `O’ ring (116) is used. As the `O’ Ring (116) is soft sealing material, the joint becomes easily leakproof. The Bullnose connector (115) is fitted to a junction block (112). To remove foreign particles present in CNG, a filter subassembly (110) is used. Only filtered CNG, flowing from the cylinder (146) enters the pressure gauge (111) and the two-stage regulator (101). This increases the life of the two-stage regulator (101) and the pressure gauge (111). However, to enable fast filling of the CNG cylinder (146), the filter position is so designed that it does not obstruct the CNG flow while filling. The pressure gauge is having an electronic output. An electronic output of the pressure gauge is connected to a level indicator (not shown). The level indicator is fitted on the vehicle dashboard. The pressure gauge (111) is configured to indicate the pressure and the available level of CNG in the cylinder to the vehicle user. The pressure gauge (111) provides an estimate of the distance that can be traveled, based on the vehicle's average running capacity, and helps to avoid the vehicle fuel tank/cylinder dry situation. Furthermore, the system (100) includes a refueling unit. The refueling unit includes a refueling adapter (102), a dust plug (103), a non-return valve (104), and a micro switch (107). CNG is filled to the CNG cylinder through the refilling adaptor (102). The non-return valve (104) prevents reverse flow through the refilling adaptor (102). The dust plug (103) is fitted on the refilling adaptor (102). The dust plug (103) needs to be removed while CNG refilling to insert the CNG filling probe. A string (105) is provided on the dust plug (103) to retain the dust plug associated with the refueling adaptor (102). The micro switch (107) turns to `OFF’ position on removal of the dust plug (103). Further, the removal of dust plug blocks the electrical supply to the engine ignition system and the starter motor. Blocking of electrical supply during CNG refilling prevents the vehicle from getting the engine to ‘ON’ state, thereby eliminates chances of accidents. The filling probe is removed once the refilling is completed. Further, the insertion of the dust plug (103) to the previous position turns the micro switch to `ON’ and establishes the electric connection between the engine ignition system and the starter motor.
The two-stage regulator (101) comprises a regulator first stage (S1) and a regulator second stage (S2).
The regulator's first stage (S1) receives CNG through a first-stage inlet orifice (135) at a preset pressure. The regulator's first stage (S1) is fitted with:
• a spring-loaded first-stage diaphragm (125) clamped between a first-stage bonnet (134) and a first-stage body (120), and
• a lever (127) and a first-stage pad (128) arrangement operably connected to the spring-loaded first-stage diaphragm (125).
The spring-loaded first diaphragm (125) flexes upwards and downwards due to CNG pressure variations inside the first stage body (120) and the lever (127) and the first stage pad (128) arrangement is operably connected to the spring-loaded first diaphragm (125) for partial opening and closing of the first stage (inlet) orifice (135) in response to the flexing movement of the spring-loaded first stage diaphragm (125).
The outlet pressure of the regulator's first stage (S1) is factory set. No adjustment is required while installing on the vehicle or in the field by the customer. A first safety relief valve (121) is fitted on the first stage body (120) and configured to protect the downstream CNG system. The first safety relief valve (121) includes an adjusting screw (133) for adjusting the spring load.
In an embodiment of the present invention, the CNG enters the regulator's first stage (S1) through the first stage inlet orifice (135) at a set pressure, for instance, P1 kg/cm2. When the pressure inside the regulator's first stage (S1) increases above the set pressure P1 kg/cm2, the first stage diaphragm (125) moves vertically upward. The upward movement of the first stage diaphragm (125) partially closes the first stage inlet orifice (135) which in turn reduces the flow/ supply and pressure of the CNG. On the other hand, when the pressure in the regulator first stage (S1) drops below the set pressure P1 kg/cm2, a spring (122) pushes the first stage diaphragm (125) downwards that partially opens the first stage inlet orifice (135). The opening of the first stage inlet orifice (135) increases the CNG pressure. The process of increase and decrease in pressure continues till an equilibrium condition is achieved. At equilibrium conditions, the first stage inlet orifice (135) remains partially open such that after the throttling process, the CNG supply at a set pressure of P1 kg/cm2 is maintained with little or no fluctuations.
The regulator's second stage (S2) is coupled to the regulator's first stage (S1) for receiving CNG through a second-stage inlet orifice (138) from the regulator's first stage (S1). The outlet of the regulator's first stage (S1) acts as an inlet to the second stage inlet orifice (138) of the regulator's second stage (S2). The regulator's second stage (S2) is fitted with:
• a spring-loaded second-stage diaphragm (119) clamped between a second-stage bonnet (117) and a second-stage body (117A),
• a spindle (129) and a second stage pad (130) arrangement operably connected to the spring-loaded second stage diaphragm (119), and
• an adjustment screw (123) for setting an outlet pressure.
The spring-loaded second-stage diaphragm (119) flexes upwards and downwards due to CNG pressure variations inside the second-stage body (117A). The spindle (129) and the second stage pad (130) arrangement is operably connected to the spring-loaded second stage diaphragm (119) for partial opening and closing of the second stage (inlet) orifice (138) in response to the flexing movement of the spring-loaded second stage diaphragm (119).
The outlet pressure of the regulator second stage (S2) is set to the desired pressure by adjusting the spring load on the second stage diaphragm (119) by rotating the adjustment screw (123). The outlet pressure of the regulator second stage (S2) is adjusted for instance P2 kg/cm2. When the pressure inside the second stage body (117A) exceeds the set pressure of P2 kg/cm2, the second stage diaphragm (119) moves upward. Due to the upward movement of the second stage diaphragm (119), the spindle (129) partially closes the second stage inlet orifice (138) of the seat (136) which in turn reduces the CNG supply. When the pressure of the regulator second stage (S2) reduces below the set pressure P2 kg/cm2, the second stage diaphragm (119) moves downward. Further, the spindle (129) opens the second stage inlet orifice (138) partially, which maintains a constant CNG supply. A second safety relief valve (124) is fitted to the second stage body (117A) and configured to protect the downstream CNG system when the pressure inside the regulator exceeds the safety limit.
In the preferred embodiment of the invention, as illustrated in Figure 2, the CNG cylinder (146) stores the CNG at a pressure of approximately 200 kg/cm2. In an operation of the present invention, the CNG at a pressure of 200 kg/cm2 enters the regulator first stage (S1) regulator through the first stage inlet orifice (135). The first stage inlet orifice (135) is maintained partially open condition by the lever (127) and the first stage pad (128) arrangement. The lever (127) and the first stage pad (128) arrangement activates the throttling process. When the pressure inside the regulator's first stage (S1) increases above the set pressure P1 kg/cm2, the first stage diaphragm (125) moves vertically upward. The upward movement of the first stage diaphragm (125) partially closes the first stage inlet orifice (135) which in turn reduces the flow/ supply and pressure of the CNG. On the other hand, when the pressure in the regulator first stage (S1) drops below the set pressure P1 kg/cm2, the first stage spring (122) pushes the first stage diaphragm (125) downwards that partially opens the first stage inlet orifice (135). The opening of the first stage inlet orifice (135) increases the CNG pressure. The opening and closing of the first stage inlet orifice (135) continue till the equilibrium state. At equilibrium conditions, the first stage inlet orifice (135) remains partially open such that after the throttling process, the CNG supply at a set pressure of P1 kg/cm2 is maintained with little or no fluctuations.
Normally, the outlet pressure of the first stage regulator (P1 Kg/cm2) remains constant. The first stage regulator (S1) absorbs the effect of variation in the CNG cylinder pressure. When the second stage chamber pressure exceeds the set pressure P2 kg/cm2, the second stage diaphragm (119) moves upwards. Due to the upward movement of the second stage diaphragm (119), the spindle (129) closes the orifice of the seat (136) which in turn reduces the CNG supply. When the pressure of the second stage regulator (S2) reduces below the set pressure P2 kg/cm2, the second stage diaphragm (119) moves downwards. Further, the spindle (129) opens the second stage inlet orifice (138) partially, which maintains a constant CNG supply. The process of pressure increase and pressure decrease continues till an equilibrium condition is achieved. In equilibrium condition, the second stage inlet orifice (138) remains partially open in such a way that after the throttling process, it maintains the CNG supply at a set pressure of P2 kg/cm2 with little or zero fluctuations.
For experimental purposes, the system (100) with the two-stage regulator (101) and the system (200) with a single-stage regulator (201) of prior art is executed at different inlet pressure and different flow condition at an ambient temperature.
Table 2: Examination/execution report of the precision control Two Stage Pressure Regulator (present invention) and Single Stage Pressure Regulator (Prior art).
System with the two stage regulator (101) of present invention System with the single stage regulator (201) of prior art
Sr. No. Inlet pressure (kg/cm2) Outlet pressure (Kg/cm2) Sr. No. Inlet pressure (kg/cm2 Outlet pressure (Kg/cm2)
20 100 200 20 100 200
Flow in LPH Flow in LPH
1 0 2.00 2.10 2.10 1 0 3.62 3.30 2.72
2 1000 2.00 2.00 2.00 2 1000 3.08 2.97 2.20
3 1500 2.00 2.00 2.00 3 1500 2.90 2.78. 2.00
4 2000 2.00 2.00 2.00 4 2000 2.72 2.53 1.72
5 2500 1.90 1.90 1.90 5 2500 2.48 2.24 1.33
6 3000 1.90 1.90 1.90 6 3000 2.18 1.89 0.80

Table 2 shows varying the inlet pressure from 20kg/cm2 to 200 kg/cm2 and the flow rate from 0LPH to 3000LPH, the outlet pressure of the precision control two-stage pressure regulator (101) varies from 2.10 kg/cm2 to 1.90 kg/cm2; against the same conditions, the outlet pressure of the single stage pressure regulator (201) varies from 3.62 kg/cm2 to 0.80 kg/cm2. The outlet pressure of the single-stage pressure regulator (201) fluctuates more drastically as compared to the precision control two-stage pressure regulator (101). The fluctuation in outlet pressure of the single-stage pressure regulator (201) affects the power and pick-up of the vehicle and increases exhaust emissions. Whereas the outlet pressure remains almost constant in precision control two-stage CNG pressure regulator (101), though flow rate and inlet pressure vary widely. Thus precision control two-stage CNG pressure regulator (101) facilitates required power and pick up in vehicles with negligible exhaust emissions.
Observations:
1) The CNG cylinder pressure is approximately 200 kg/cm2 in the fully filled state. During vehicle use, CNG pressure drops from 200kg/cm2 to 20 kg/cm2, as CNG is consumed to run the vehicle. The CNG cylinder pressure continues to drop till the next refilling. The drastic drop in CNG cylinder pressure affects greatly the outlet pressure of the single-stage pressure regulator.
2) However, the effect of drastic CNG pressure drop (from 200kg/cm2 to 20 kg/cm2) in the two-stage CNG pressure regulator (101) is absorbed in the regulator's first-stage pressure (S1). Thus the fluctuation in outlet pressure at the regulator's first stage (S1) is comparatively lower than the fluctuation in CNG cylinder pressure of the single-stage regulator (201).
The outlet pressure of the regulator's first stage (S1) having narrow band fluctuation acts as an inlet pressure for the regulator's second stage (S2). The narrow band/ low fluctuations in the inlet pressure of the regulator second stage (S2) provides constant outlet pressure to the gas injector (141). Hence, the controlled and stable CNG pressure flow is supplied to the CNG injector (141).
3) Hence, from Table 2, it is observed that the variation in the outlet pressure of the two-stage regulator (101) of the present invention is almost negligible as compared to the outlet pressure variation of the single-stage pressure regulator (201) of the prior art. In the precision two-stage CNG pressure regulator (101), the CNG cylinder pressure reduces from 200 kg/cm2 to 20 kg/cm2 in two stages, and flow to the regulator varies from the idling flow condition to the full throttle flow condition.
4) The supply of precision-controlled CNG pressure to the CNG injector controls the pollutant emission from the engine which in turn meets the stringent BSVI emission norms.
Advantages of the invention:
? The two-stage regulator (101) provides a controlled and stable CNG supply to the vehicle engine.
? The two-stage regulator (101) maintains the stability of pressure at the outlet through two stages of pressure regulators.
? The two-stage regulator (101) increases safety by eliminating of steel tubing and joints.
? The two-stage regulator (101) prevents the vehicle from getting started during CNG refilling by blocking the electric supply.
? The two-stage regulator (101) makes the system (100) more efficient as compared to the system with single-stage pressure regulator (201).
The foregoing descriptions of specific embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the present invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the present invention and its practical application, to thereby enable others skilled in the art to best utilize the present invention and various embodiments with various modifications as are suited to the particular use contemplated. It is understood that various omission and substitutions of equivalents are contemplated as circumstance may suggest or render expedient, but such are intended to cover the application or implementation without departing from the scope of the present invention.
, Claims:We claim:
1. A precision control two-stage CNG pressure regulator (101) with multi-features receiving CNG from a CNG cylinder (146) through a refueling unit and supplying CNG to a vehicle engine through a filter solenoid valve (143), the precision control two-stage CNG pressure regulator (101) coupled to the refueling unit with a bullnose connector (115) in a sealing manner, the precision control two-stage gas pressure regulator (101) with multi features comprising
a regulator first stage (S1) receiving CNG through a first stage inlet orifice (135) at a set pressure from the refueling unit, the regulator first stage (S1) having:
a spring-loaded first-stage diaphragm (125) clamped between a first-stage bonnet (134) and a first-stage body (120), the spring-loaded first-stage diaphragm (125) flexing upwards and downwards due to CNG pressure variations inside the first stage body (120),
a lever (127) and a first stage pad (128) arrangement operably connected to the spring-loaded first stage diaphragm (125) for partial opening and closing of the first stage inlet orifice (135) in response to the flexing movement of the spring-loaded first stage diaphragm (125); and
a regulator second stage (S2) coupled to the regulator first stage (S1) to receive CNG through a second stage inlet orifice (138) from the regulator first stage (S1), the regulator second stage (S2) having:
a spring-loaded second-stage diaphragm (119) clamped between a second-stage bonnet (117) and a second-stage body (117A), the spring-loaded second-stage diaphragm (119) flexing upwards and downwards due to CNG pressure variations inside the second-stage body (117A),
a spindle (129) and a second stage pad (130) arrangement operably connected to the spring-loaded second stage diaphragm (119) for partial opening and closing of the second stage inlet orifice (138) in response to the flexing movement of the spring-loaded second stage diaphragm (119), and
an adjustment screw (123) for setting an outlet pressure of the regulator second stage (S2),
wherein fluctuation in CNG pressure during vehicle use is controlled in two stages by opening and closing the first stage inlet orifice (135) and the second stage inlet orifice (138) till the set pressure is maintained inside the first body (120) and the second body (117A).
2. The precision control two-stage CNG pressure regulator (101) with multi features as claimed in claim 1, wherein the outlet pressure of the regulator second stage (S2) is set to a desired pressure by adjusting the spring load on the second stage diaphragm (119) by rotating the adjustment screw (123).
3. The precision control two-stage CNG pressure regulator (101) with multi features as claimed in claim 1, wherein the regulator first stage (S1) is fitted with a first safety relief valve (121) for releasing the pressure when the regulator first stage outlet pressure reaches more than 1.5 times the preset pressure.
4. The precision control two-stage CNG pressure regulator (101) with multi features as claimed in claim 1, wherein the regulator second stage (S2) is fitted with a second safety relief valve (124) for releasing the pressure when the regulator second stage outlet pressure reaches more than 1.5 times the preset pressure.
5. The precision control two-stage CNG pressure regulator (101) with multi features as claimed in claim 1, wherein the refueling unit includes a refueling adapter (102), a dust plug (103), a non-return valve (104), and a micro switch (107).
6. The precision control two-stage CNG pressure regulator (101) with multi features as claimed in claim 1, wherein the outlet of the regulator first Stage (S1) is the second stage inlet orifice (138) of the regulator second stage (S2).