JP3328887B2 - Operation control device for gaseous fuel engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an operation control apparatus for a gaseous fuel engine, and more particularly to an improvement in an air-fuel ratio control method capable of protecting a catalyst in an exhaust system when the engine is rapidly decelerated.

[0002]

2. Description of the Related Art In general, liquefied petroleum gas (LPG: Liquid
ied Petroleum Gas) and liquefied natural gas (LNG: Liquid)
Since gaseous fuels such as ied Natural Gas) have the following features, they are considered to be extremely promising as alternative fuels to gasoline. That is, i) there is no harmful lead compound or irritating aldehyde and the sulfur content is small, so that the generation of sulfur dioxide gas is small. Moreover, since the distribution to each cylinder can be made uniform, the combustion in each cylinder can be made uniform. As a result, exhaust gas can be cleaned. ii) The generation of carbon due to combustion is small, and the generation of sludge is also small. In particular, the above advantage i) is very important in view of environmental problems.

[0003]

In a gaseous fuel engine using such gaseous fuel as a fuel, a catalytic converter is generally installed in an exhaust system like a gasoline engine due to a demand for further purification of exhaust gas. . In the engine equipped with the catalytic converter, the throttle valve is closed at the time of rapid deceleration, so that the charging efficiency in the combustion chamber is low, and a misfire may occur. As a result, unburned fuel in the combustion chamber flows into the exhaust device and burns in the catalyst, which may damage the catalyst.

The present invention has been made in view of the above circumstances, and has as its object to provide an operation control device for a gaseous fuel engine that can protect a catalyst during sudden deceleration.

[0005]

According to a first aspect of the present invention, there is provided a gas fuel mixer provided with a gas fuel mixer, wherein the gas fuel passage is connected to the fuel supply chamber via a main jet downstream of the fuel supply chamber in the middle of the intake passage connected to the intake valve opening. The bleed air passage connected to the fuel supply chamber is provided with a bleed air control valve for variably controlling the area of the passage to control the amount of gas fuel, and the oxygen concentration in the exhaust gas is adjusted so that the mixture becomes a predetermined air-fuel ratio. In the operation control device for a gaseous fuel engine, wherein the bleed air control valve is feedback-controlled based on a fuel cutoff valve for introducing air into the fuel supply chamber, the engine speed is equal to or higher than a predetermined boundary speed. If it is determined that rapid deceleration is occurring because the intake negative pressure is equal to or higher than the predetermined boundary negative pressure, the feedback control is released and the fuel cutoff is performed. By increasing the degree of opening is characterized by providing an air-fuel ratio control means for reducing or blocking than during the stoichiometric air-fuel ratio of the fuel amount supplied to the engine through the intake passage from the fuel supply chamber. According to a second aspect of the present invention, in the first aspect, the air-fuel ratio control means supplies the fuel to the engine by increasing the opening degree of the fuel cutoff valve as the engine speed increases when the sudden deceleration is determined. It is characterized in that the amount of reduced fuel is increased.

[0006]

In the operation control apparatus for a gaseous fuel engine according to the present invention, when the engine is rapidly decelerated, an air-fuel mixture having an air-fuel ratio of λ> 1, that is, a lean air-fuel mixture is supplied to the engine combustion chamber.
As a result, even if misfire occurs in the combustion chamber, the amount of unburned fuel is reduced, and as a result, combustion of fuel in the catalyst in the exhaust device is suppressed, and the catalyst can be protected. Further, in the operation control device for the gaseous fuel engine according to the present invention, the lean mixture is supplied to the engine combustion chamber by increasing the opening of the fuel cutoff valve to increase the amount of air introduced into the fuel supply chamber. It is sufficient that the fuel cutoff valve can control a few percent of the fuel flow rate at the time of supply of the lean air-fuel mixture, whereby the fuel cutoff valve can be downsized, and as a result, the responsiveness at the time of rapid deceleration of the engine and after returning to the feedback control can be improved. . On the other hand, in the case of supplying a lean mixture by reducing the opening of the fuel supply valve that supplies the fuel to the fuel supply chamber, the fuel supply valve is relatively controlled so as to cope with the maximum fuel flow rate. It is necessary to use a large one, which results in a decrease in responsiveness.

[0007]

Embodiments of the present invention will be described below with reference to the accompanying drawings. 1 and 2 are diagrams for explaining an operation control device of a gaseous fuel engine according to one embodiment of the present invention. FIG. 1 is a schematic configuration diagram of a gaseous fuel engine to which this embodiment is applied, and FIG. 4 is a flowchart illustrating a control routine of air-fuel ratio feedback control when the engine is rapidly decelerated.

In FIG. 1, reference numeral 1 denotes a water-cooled, four-cylinder, four-valve gas fuel engine, which comprises a cylinder block 2 and a cylinder head 3 stacked on a crankcase (not shown) and fastened with head bolts. 3 has a structure in which a head cover 4 is mounted. A piston 5 is slidably inserted into each of four cylinder bores 2a formed in the cylinder block 2, and each piston 5 is connected to a crankshaft (not shown) via a connecting rod.

At the lower part of the cylinder head 3, a combustion recess 3a is provided. A combustion chamber 6 is formed by the combustion recess 3a, the cylinder bore 2a, and the head 5a of the piston 5. The combustion recess 3a has two intake valve openings 3b and two exhaust valve openings 3c. The openings 3b and 3c are formed by the openings of the generally ring-shaped valve seats 7 and 8 which are press-fitted into these portions, respectively. A valve head 10a of the intake valve 10 can be opened and closed in each intake valve opening 3b, and a valve head 11a of the exhaust valve 11 can be opened and closed in each exhaust valve opening 3c. It is arranged so that it can be in close contact with the seat surface. These intake and exhaust valves 1
Intake and exhaust lifters 12, 13 are mounted on the upper ends of 0, 11, respectively. On each of the lifters 12, 13, intake and exhaust camshafts 14, 15 for pressing the lifters 12 and 13 are arranged in a direction perpendicular to the cylinder axis and parallel to each other. The ignition plug 1 is located inside the cylinder head 3.
The electrode portion of the ignition plug 16 is arranged at the center of the combustion recess 3a. Further, a cooling jacket 25 in which a coolant liquid is circulated by a coolant pump (not shown) is provided in the cylinder block 2 and the cylinder head 3. The coolant is cooled by a known method through an external heat exchanger (not shown).

In the side wall 3d of the cylinder head 3,
An intake passage 17 communicating with the combustion chamber 6 is formed through the intake valve opening 3b.
An exhaust passage 18 communicating with the combustion chamber 6 through an exhaust valve opening 3c is formed in e. The intake passage 17
One end of an intake manifold 19 is connected to a wall opening of the exhaust passage 18, and one end of an exhaust manifold 20 is connected to a wall opening of the exhaust passage 18. A plenum chamber 21 is provided at the other end of the intake manifold 19. At the outlet 20a at the other end of the exhaust manifold 20,
A catalytic converter 22 having a catalyst layer is connected.
This catalyst layer comprises carbon monoxide (CO) and hydrocarbons (H
It contains so-called three-way catalyst for performing reduction of the oxidized and the nitrogen oxides of C) (NO _X). Catalytic converter 22
Exhaust gas is discharged into the atmosphere through an exhaust / silence system (not shown). Further, the exhaust manifold 20 is provided with an O ₂ sensor 23 for detecting the oxygen concentration in the exhaust gas.
As the O ₂ sensor 23, the air-fuel ratio (A /
F) or the type to detect when A is on the rich side
Any type that detects when F is on the lean side may be used.

A gas mixture forming device 30 for forming a gas mixture to be supplied to the combustion chamber 6 via the intake manifold 19 is disposed on a side of the gaseous fuel engine 1. The mixture forming device 30 has a variable venturi mixer 31. The mixer 31 has a main body 32 whose lower opening is connected to the intake manifold 19 side. An intake passage 33 is formed in an upper portion of the main body 32, and an air cleaner 35 is connected to the intake passage 33. Thereby, the air cleaner 3
The air introduced from the air inlet port 36 and filtered by the filter element is supplied into the intake passage 33.

The air cleaner 35 is provided with an air flow meter 49 for measuring the amount of intake air, and the output of the air flow meter 49 is input to the ECU 92. Although not shown, the air cleaner 35 is provided with a clogging sensor for detecting clogging of the filter element, and the output of the clogging sensor is similarly input to the ECU 92. Further EC
U92 includes the throttle position of the throttle valve 48,
Coolant temperature, engine speed, O ₂ sensor 23
And various signals such as the output of the exhaust gas, the exhaust temperature, and the output of the negative pressure sensor.

The mixer 31 is provided slidably in the chamber 38 and the intake passage 33.
And a piston 39 protruding inward. A coil spring 40 for urging the piston 39 in the closing direction of the intake passage 33 is contracted in the chamber 38. At the tip of the piston 39, a metering rod (needle valve) 44 cooperating with the main jet 43 of the fuel supply chamber 42 is provided. The main jet 43 and the needle valve 44 have such a shape that the A / F can be maintained substantially constant with the average value of the opening of the bleed air control valve 84 described later being substantially constant for any intake flow rate. Have. A bleed port 46 communicating with the inside of the chamber 38 is formed at an end of the piston 39, and an atmosphere port 47 that opens to the atmosphere is formed at an upper portion of the chamber 38. The atmospheric pressure acts on the piston 39 in the opening direction of the intake passage 33. The atmosphere port 47 is provided in the intake passage 3 upstream of the venturi where the main jet 43 opens.
3, and in this case also the piston 39
, The atmospheric pressure acts in the opening direction of the intake passage 33.

With this configuration, when the pressure on the downstream side of the piston 39 in the intake passage 33 becomes negative, the piston 3
9 moves to the chamber 38 side to open the flow path, whereby the flow path area can be effectively changed, and the throat portion where the main jet 43 opens has a substantially constant negative pressure. It is to be maintained in a state. A throttle valve 48 that opens and closes by a throttle operation is provided downstream of the piston 39 in the intake passage 33.

The mixer 31 has an idle discharge line 5 extending from the fuel supply chamber 42.
1, an idle circuit 50 including a fuel cutoff valve 52, an adjustable needle valve 53 and an idle port 54 is provided. The idle port 54 opens in the intake passage 33 downstream of the throttle valve 48 at an idle position. The opening and closing of the fuel cutoff valve 52 is controlled by the ECU 92, whereby the amount of fuel passing through the idle discharge line 51 is controlled. During idling, fuel is supplied from the idle circuit 50.

A pressure regulator (vaporizer, regulator) 60 for supplying gaseous fuel to the fuel supply chamber 42 is provided. Gaseous fuel stored in a liquid state under pressure in a high-pressure source (not shown) is introduced into the regulator 60 through an introduction pipe 61.
As the gaseous fuel, for example, butane, propane, a mixture thereof, or other known gaseous fuel is used.

The regulator 60 has a main body (housing) 62. An introduction passage 63 communicating with the introduction pipe 61 is formed in the housing 62. The introduction passage 63 extends to the first pressure adjustment port 64, and
The opening and closing of the pressure adjustment port 64 is controlled by a first pressure adjustment valve 65. The first pressure regulating valve 65 is operated by a first biasing member 68 including an adjusting screw 66 and a spring 67. A first cover plate 69 is mounted on the housing 62, thereby forming a first pressure adjustment chamber 70 in the housing 62. By adjusting the first biasing member 68, the pressure of the gaseous fuel in the first pressure adjusting chamber is set to about 0.3 kg / cm ² .

A diaphragm 72 and a second cover plate 73 are mounted on the housing 62 on the side opposite to the first cover plate 69, thereby forming a second pressure adjusting chamber 74. The second pressure adjustment chamber 74 is connected to the first pressure
The pressure adjustment chamber 70 is communicated. A second pressure regulating valve 7 that can be opened and closed is provided at an opening of the passage 75 on the side of the second pressure regulating chamber.
The operation of the second pressure regulating valve 76 is controlled by a second biasing member 77 that is interlocked with the diaphragm 72. Atmospheric pressure acts on the back side of the diaphragm 72 via an atmosphere port 73a. By adjusting the second biasing member 77, the pressure of the gaseous fuel in the second pressure adjusting chamber 74 is set to a pressure slightly lower than the atmospheric pressure, and the gaseous fuel thus set is supplied to the upper fuel supply. The fuel is supplied to the fuel supply chamber 42 through the passage 78. Note that a heating passage 80 is provided in the housing 62. The coolant heated by the cooling jacket 25 of the engine 1 circulates through the heating passage 80. Thereby, the regulator 6
A more stable gas temperature is maintained inside the 0, and a better vaporization and regulating action is performed.

In the fuel supply chamber 42, one end of a bleed air passage 82 for introducing bleed air into the fuel supply chamber 42 is opened, and the bleed air passage 82 is provided with a bleed air control valve 84. It is connected to the. The bleed air control valve 84 has a bleed air passage 8 having one end opened downstream of the air cleaner 35.
5, air is introduced. The bleed air control valve 84 includes a valve element 86 that opens and closes when driven by a stepping motor 90. The operation of the valve element 86 controls the amount of bleed air to the fuel supply chamber 42. The drive of the stepping motor 90 is controlled (feedback control) by the ECU 92 based on each output signal from the O ₂ sensor 23 and the air flow meter 49. In addition, as the engine operating conditions,
There are flow path resistance of the air cleaner 35, atmospheric pressure drop due to use at high altitude, and the like.

The fuel supply control valve 100 is controlled so as to compensate for the amount of fuel in accordance with the engine operating conditions in accordance with the movement of the valve member of the bleed air control valve 84. here,
The engine operating conditions include the composition of the fuel (the composition ratio of propane and butane in LPG), the flow path resistance of the air cleaner 35, the atmospheric pressure drop associated with use at high altitude, and the like. That is, the opening degree of the fuel supply control valve 100 is controlled by the compensation function of the fuel supply control valve 100 such that the average of the number of steps of the bleed air control valve 84 is maintained at a substantially constant value (50). You. Therefore, even when the operating conditions of the engine change due to the use of fuels of various compositions,
Without providing a sensor for detecting engine operating conditions, λ = 1 is automatically maintained under all operating conditions, and more accurate control of the air-fuel ratio over a wide range is possible.

Now, consider the amount of fuel required for a certain amount of air to form a stoichiometric (λ = 1) air-fuel mixture. This amount of fuel depends on the ratio of propane to butane. For example, the amount of fuel required to form a stoichiometric mixture with 100 liters of air is 100 liters of propane ... 42 liters and 100% butane ... 32 liters. That is, 100% propane requires more fuel. Therefore, 100
The opening degree of the fuel supply control valve 100 is larger when 100% propane is used than when 100% propane is used. For these reasons, the fuel supply control valve 10
0 is provided.

If only the bleed air control valve 84 is provided, if the fuel composition changes, the control width on either the lean side or the rich side becomes narrower. This is because when the fuel composition changes, the median of the number of steps of the bleed air control valve 84 when λ = 1 shifts to the fully closed or fully open side, and the feedback control must be performed based on the shifted value. Because. On the other hand, with the fuel supply control valve 100 alone, in order to control the amount of fuel, the amount of fuel supplied to the intake passage 33 so that the opening area of the throttle portion 42a is always smaller than the opening area of the main jet 43. It is necessary to change the diameter of the throttle 42a in accordance with the opening degree of the main jet 43 so that the diameter of the throttle 42a is controlled by the opening area of the throttle 42a. Thus, when the intake flow rate changes and the opening area of the main jet 43 changes, the opening area of the main jet 43 is reduced before changing the number of steps of the fuel supply control valve 100 for feedback control. It becomes necessary to control the opening area of the diaphragm 42a, and a delay occurs in the feedback control. By providing the bleed air control valve 84 and the fuel supply control valve 100 in this manner, a wide control range of the air-fuel ratio can be ensured, and the feedback control can be performed quickly.

The above λ is defined as follows.
That is, λ = F / F _c where F is the actual air-fuel ratio and F _c is the stoichiometric stoichiometric air-fuel ratio. Therefore, in the stoichiometric mixture, λ = 1 always regardless of the type and composition of the gaseous fuel.
It is. However, even if the air-fuel ratio in the stoichiometric state indicated by the same λ = 1, it naturally has a different meaning if the ratio between butane and propane is different. The air-fuel ratio of the stoichiometric mixture with λ = 1 is 100% propane ... 15.7 100% butane ... 15.5. Therefore, if the ratio between butane and propane is different, the amount of fuel (volume) required to obtain a stoichiometric air-fuel ratio of λ = 1 for a certain amount of air is greatly different, which is a major problem. is there.

By providing the fuel supply control valve 100, the amount of fuel from the regulator 60 can be directly controlled. The controlled fuel is continuously and reliably supplied into the intake passage 33, whereby the A / F can be made uniform over a wide range of the fuel amount. In addition, since the control of the fuel amount is performed based on the signal from the O ₂ sensor 23, the A / A is within the range of the window where the purification rate of the three-way catalyst is high.
F can be controlled. Also, there is no need to provide a slow system or other various parts to adjust the A / F,
The structure becomes simple. Although not clearly shown in FIG. 1, the fuel supply control valve 100 has a structure in which the valve body is held at an arbitrary position, that is, the opening is held at an arbitrary intermediate position. The fuel supply control valve 10
Zero useless movement can be eliminated, and quick control becomes possible.

Further to the gaseous fuel engine 1, EGR device is provided for reducing NO _X in the exhaust gas. This EGR device has an EGR valve 56, and the EGR valve 56 allows the exhaust manifold 20 to be operated.
From the first EGR line 57 to the second EGR line 58
Through the plenum chamber 2 of the intake manifold 19
The amount of exhaust gas returning to 1 is controlled. An EGR regulator 110 is provided as a part of the EGR device. Further, a negative pressure switch 112 is provided downstream of the throttle valve 48 in the intake passage 33, and a fuel switching valve 114 is provided in the idle discharge line 51.
Is provided.

Further, a fuel cutoff valve 120, an idle speed control valve 130, and an auxiliary fuel supply valve 140 are provided. The fuel cutoff valve 120 is for shutting off fuel supply to the combustion chamber when the engine is suddenly decelerated, and has a filter element 121 for drawing air. When the throttle valve 48 is rapidly throttled during rapid deceleration, that is, during high-speed rotation of the engine, the fuel cutoff valve 120 is opened, so that a large amount of air flows from the filter element 121 through the bypass passage 122 into the fuel supply chamber 42. Has been introduced.

The idle speed control valve 130 is provided in an idle bypass passage 131 formed downstream of the intake passage 33, and is generally an electrically operated control valve. The idle bypass passage 131 is connected to the intake passage 3
Throttle valve 48 in idle position within 3
The idle speed control valve 130 controls the intake flow rate flowing through the idle bypass passage 131 based on a control signal from the ECU 92 to adjust the idle speed (rotation speed). belongs to. That is, when the idle speed decreases, the opening of the idle speed control valve 130 increases to bypass the intake air, and when the idle speed is high, the opening of the idle speed control valve 130 decreases. Thus, the idle speed can be stabilized.

The auxiliary fuel supply valve 140 is generally an electrically operated control valve.
0 to the flow path 142 in the first pressure regulation chamber 70
And a bypass passage 143 for supplementarily supplying enrichment fuel to the plenum chamber 21. This auxiliary fuel supply valve 140 is also EC
It is controlled based on a control signal from U92. The supply of the enrichment fuel is performed to determine whether or not the O ₂ sensor 23 has been activated when the engine is started.

Next, a method of operating the gas fuel engine 1 at the time of sudden deceleration will be described with reference to FIG. FIG. 2 is a control routine showing an operation method during rapid deceleration. In step S1, the program determines whether the engine speed is higher than a predetermined speed (boundary speed). If not, the engine is running in a normal state where fuel cut is not required, and the process of step S1 is repeated. If the engine speed is higher than the predetermined speed, the process proceeds to step S2, and it is determined whether the intake negative pressure detected by the negative pressure switch 112 is higher than a predetermined pressure (boundary negative pressure). If not, it is determined that the engine is in the normal state, and the program repeats the processing of step S1 and step S2. If it is determined in step S2 that the intake negative pressure is higher than the predetermined pressure, the program proceeds to step S3. That is, when the determinations in both steps S1 and S2 are yes, it is determined that the engine is running at a high speed and the throttle valve 48 is closed, so-called a rapid deceleration state of the engine.

In step S3, the fuel cutoff valve 120 is opened. Then, air is introduced from the filter element 121, and the air is introduced into the fuel supply chamber 42 through the bypass passage 122. If air (including bleed air) is supplied into the fuel supply chamber 42, the throttle 4
The amount of fuel supplied to the fuel supply chamber 42 through 2a is reduced, and as a result, the fuel supply into the intake passage 33 is suppressed or cut. Normally, the amount of fuel supplied to the intake passage 33 is controlled by the operation of the bleed air control valve 84 so that the state of λ = 1 is maintained. In this state, the atmosphere is further supplied to reduce the amount of fuel. In order to suppress this, at the time of rapid deceleration, an air-fuel mixture (lean mixture) having an air-fuel ratio of λ> 1 is supplied into the combustion chamber 6, and even if a misfire occurs in the combustion chamber 6, the mixture will remain in the catalytic converter 22. The amount of unburned unburned fuel is reduced, combustion in the catalyst can be prevented, and the inside of the catalyst can be prevented from becoming high temperature. As a result, the catalyst can be protected.

Next, the process proceeds to step S4. This step S4 is a step of introducing hysteresis so that fuel supply is not restarted immediately after the rapid deceleration state has passed.
That is, in step S4, it is determined whether the engine speed is lower than the predetermined value (boundary rotation speed) determined in step S1 by a predetermined value α or more, or the intake negative pressure is lower than the predetermined value (boundary negative pressure). Is determined to be smaller than the predetermined value β (close to the atmospheric pressure). These indicate that the rapid deceleration state has ended. If any of these states exists, the process proceeds to step S5. In step S5, the fuel cutoff valve 120 is closed, and fuel supply is restarted using the above-mentioned hysteresis. Next, in step S6, a transition is made to normal feedback control according to other parameters.

As described above, according to the present embodiment, at the time of rapid deceleration, the lean air-fuel mixture is supplied into the combustion chamber 6 by opening the fuel cutoff valve 120, so that misfire occurs in the combustion chamber 6 at the time of rapid deceleration. However, combustion in the catalyst can be prevented, thereby protecting the catalyst. Also, a fuel cutoff valve 12 is used as an atmospheric control valve.
By using 0, it is possible to control the air-fuel ratio to λ> 1 while maintaining the average value of the number of steps of the bleed air control valve 84 at a substantially constant value (50). Responsiveness of the feedback control can be improved.

The fuel cutoff valve 120 is turned on.
Not only the / OFF valve but also a valve capable of holding an intermediate opening position may be used. In this case, the valve opening of the fuel cutoff valve is changed according to the opening of the throttle valve. The amount of fuel supplied to the intake passage may be reduced by increasing the valve opening.

The present invention is not limited to a reciprocating engine but can be applied to a rotary engine. In each of the above embodiments, an example in which the present invention is applied to a four-cylinder engine has been described. However, the present invention can be similarly applied to a multi-cylinder engine other than the four-cylinder engine.

[0035]

As described above, in the operation control apparatus for a gaseous fuel engine according to the present invention, λ> 1 when the engine suddenly decelerates.
Is supplied to the engine combustion chamber, so that even if a misfire occurs in the combustion chamber, the amount of unburned fuel flowing into the exhaust system can be reduced, thereby protecting the catalyst. This has the effect of improving the responsiveness when returning to the feedback control after the end of sudden deceleration.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a gaseous fuel engine employing an operation control device according to an embodiment of the present invention.

FIG. 2 is a flowchart illustrating a control routine of air-fuel ratio feedback control during rapid deceleration of the engine.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Gas fuel engine 6 Combustion chamber 20 Exhaust manifold (Exhaust device) 22 Catalytic converter 30 Mixture forming device 92 ECU (Operation control device, Air-fuel ratio control means) 120 Fuel cutoff valve (Introduction valve)

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-61-255240 (JP, A) JP-A-53-137337 (JP, A) JP-A-61-210261 (JP, A) 19821 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) F02D 41/00-45/00 F01N 3/24 F02D 19/02 F02M 21/02

Claims (2)

(57) [Claims] 1. A gas fuel mixer comprising a gas fuel mixer connected to an intake valve opening.
The gas fuel passage is connected to the fuel supply chamber in the middle of the intake passage.
Connected via a main jet downstream of the fuel supply
The area of the bleed air passage connected to the
Bleed air control to control gas fuel amount with variable control
A valve is installed, and the exhaust gas is adjusted so that the air-fuel mixture has a predetermined air-fuel ratio.
Bleed air control valve based on the oxygen concentration
In an operation control device for a gaseous fuel engine that performs a back control, an atmosphere is introduced into the fuel supply chamber.
Provide a fuel cut-off valve to
The number of rotations is equal to or greater than and the intake negative pressure is equal to or greater than a predetermined boundary negative pressure.
When it is determined that sudden deceleration is taking place, a feedback system is
Control and increase the opening of the fuel cutoff valve
Through the intake passage from the fuel supply chamber
The amount of fuel supplied to the engine is reduced
Alternatively, an operation control device for a gaseous fuel engine provided with air-fuel ratio control means for shutting off . 2. The air-fuel ratio control means according to claim 1,
Indicates that the engine speed is high when it is determined that sudden deceleration has occurred.
By increasing the opening of the fuel cutoff valve,
An operation control device for a gaseous fuel engine, characterized in that a reduction amount of fuel supplied to an engine is increased .