JP2001200760A - Stationary gas engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a stationary gas engine, capable of making fuel in a rich state for regeneration of a NOx storage reducing catalyst with no accompaniment of change in the rotational speed or deterioration of fuel consumption, in the gas engine provided with the NOx storage reducing catalyst. SOLUTION: A venturi part 118a is provided in an intake passage 111 connecting an air inlet port 117a and a combustion chamber 161, a gas fuel supply passage 162 is connected to this venturi part, a main fuel control valve 123a and a pressure reducing valve 122 are provided in this gas fuel supply passage 162, a fuel branch passage 163 branching from the gas fuel supply passage 162 in the upstream of this pressure-reducing valve 122 to be connected to the intake passage 111 downstream of the venturi part 118a is provided, a fuel correction control valve 123b is provided in this fuel branch passage 163, a NOx storage reducing catalyst 170 is provided in an exhaust passage 112 which communicates with the combustion chamber 161, a NOx sensor 1k detecting NOx concentration is provided in the exhaust passage 112 downstream of this NOx storage reducing catalyst 170, and a control device for controlling the opening of the fuel correction control valve in accordance with the detected concentration of this NOx sensor 1k is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a stationary gas engine, and more particularly to a gas engine provided with a NOx storage reduction catalyst.

[0002]

2. Description of the Related Art Stationary gas engines are used in gas engine heat pumps using natural gas and refined gas as fuel, power generation devices by cogeneration, and gas filling devices. In this stationary gas engine, gas fuel is discharged to a venturi of a carburetor or mixer provided on the intake passage, and an air-fuel mixture corresponding to the load is supplied to the combustion chamber by adjusting the opening of a throttle valve on the downstream side. I do. A fuel control valve is provided in a fuel supply passage communicating with the gaseous fuel discharge portion, and a supply amount of fuel gas is adjusted to control an air-fuel ratio. Such a gas engine constitutes a gas heat pump type air conditioner using together with a compressor that circulates a refrigerant, and constitutes a gas filling device using together with a compressor that compresses gas fuel and fills it into a gas tank or the like.

[0003] Such a stationary gas engine is operated at a target rotational speed determined by the demands of the device side, and since it is a stationary type, the fluctuation of the rotational speed greatly affects the device side. Therefore, the fluctuation of the rotational speed is minimized. It is necessary to maintain stable operation.

On the other hand, in such a stationary gas engine, as one means for purifying NOx which is a harmful substance in exhaust gas, lean combustion operation is enabled and a NOx storage reduction catalyst (absorption decomposition catalyst) is provided in an exhaust system. ) Is used.

This NOx storage reduction catalyst uses, for example, alumina (Al ₂ O ₃ ) as a carrier,
Potassium (K), sodium (Na), lithium (L
i), at least one selected from alkali metals such as cesium (Cs), alkaline earths such as barium (Ba) and calcium (Ca), or rare earths such as lanthanum (La) and yttrium (Y); (Pt) or platinum (Pt) and a noble metal such as rhodium (Rh).

Such a NOx storage reduction catalyst absorbs NOx in an air-fuel ratio lean oxidizing atmosphere, and is reduced by a reducing agent such as HC or CO in exhaust gas in a rich air-fuel ratio reducing atmosphere to form N _2. Is released as If the air-fuel ratio lean state continues for a long time, the NOx storage reduction catalyst saturates and no longer absorbs NOx. Therefore, when the NOx absorption amount approaches the NOx absorption saturation capacity of the catalyst, the air-fuel ratio rich state is established and the catalyst is reduced. It is necessary to release the absorbed NOx to regenerate the catalyst.

[0007] As an engine equipped with such a NOx storage reduction catalyst, an exhaust gas purifying apparatus for an internal combustion engine has been disclosed in which the acceleration feeling is improved without deteriorating HC emissions in the exhaust passage of an automobile engine. (Japanese Patent No. 2757698). The exhaust gas purifying apparatus described in this patent publication enriches the air-fuel ratio by injecting an increased amount of fuel from a fuel injection valve when the vehicle is accelerating, and uses the exhaust gas as a reducing atmosphere for regeneration of the catalyst.

[0008]

However, the technique disclosed in the above-mentioned patent publication aims to improve the feeling of an automobile engine using a fuel injection valve during acceleration, and is simply applied to a stationary engine. It is not possible. In particular, in a stationary engine, it is necessary to sufficiently suppress fluctuations in the rotation speed. In addition, when the lean combustion operation is intended to reduce NOx and improve fuel efficiency, the rotation speed fluctuation is increased when the air-fuel ratio is enriched for catalyst regeneration. At the same time, it is necessary to suppress deterioration of fuel efficiency.

The present invention has been made in consideration of the above-mentioned prior art, and in a gas engine provided with a NOx storage reduction catalyst, the fuel for regeneration of the NOx storage reduction catalyst can be produced without causing fluctuations in rotation speed and deterioration of fuel efficiency. It is an object of the present invention to provide a stationary gas engine capable of enriching gas.

[0010]

To achieve the above object, according to the present invention, a venturi portion is provided in an intake passage communicating an air intake and a combustion chamber, and a gas fuel supply passage is connected to the venturi portion. A main fuel control valve and a pressure reducing valve are provided in the gas fuel supply passage, and a fuel branch passage branched from the gas fuel supply passage on the upstream side of the pressure reducing valve and connected to an intake passage on the downstream side of the venturi section is provided. A fuel correction control valve is provided in the fuel branch passage, a NOx storage reduction catalyst is provided in an exhaust passage communicating with the combustion chamber, and NOx concentration is detected in an exhaust passage downstream of the NOx storage reduction catalyst.
A stationary gas engine provided with an x sensor and a control device for controlling the opening of the fuel correction control valve in accordance with the concentration detected by the NOx sensor.

According to this configuration, by controlling the opening of the fuel correction control valve provided in the fuel branch passage by the control device, the torque at the air-fuel ratio in the lean state at the time of NOx absorption by the catalyst can be represented on the torque characteristic curve. Fuel is supplied into the intake passage so as to obtain a rich air-fuel ratio that can obtain the same torque, whereby it is possible to suppress torque fluctuation and rotation speed fluctuation. At this time, with the main fuel control valve in the gas fuel supply passage performing fuel supply to obtain a rotation speed corresponding to the required load on the system side and maintaining a constant rotation, the fuel supply passage upstream of the pressure reducing valve in the fuel supply passage is maintained. Since high-pressure gas fuel is supplied from the fuel branch passage into the intake passage on the downstream side of the venturi, where the intake negative pressure is large, gas fuel is instantaneously supplied due to a large pressure difference, resulting in a rich atmosphere necessary for catalyst regeneration in a short time, resulting in poor fuel economy. Can be suppressed.

In a preferred configuration example, the control device is configured to increase the opening of the fuel correction control valve as the detected concentration of NOx increases.

According to this configuration, the NOx concentration is detected downstream of the storage reduction catalyst in the exhaust passage, and when the concentration is equal to or higher than the predetermined value, the control device determines that the absorption capacity of the catalyst is insufficient, and the control device determines that the concentration is low. As the absorption capacity decreases, the supply capacity of the gas fuel for reducing atmosphere is increased because the absorption capacity is reduced, thereby achieving a reliable reduction regeneration operation.

[0014] In a further preferred embodiment, the engine includes an engine speed sensor, a throttle provided downstream of the venturi section, and throttle opening adjusting means. The control device is provided when the throttle opening is small. Alternatively, when the engine speed is low, the fuel correction control valve of the branch passage is opened.

According to this configuration, when the throttle opening is small or the engine speed is small and the intake negative pressure is large, the fuel is supplied from the branch passage so that minute fuel can be instantaneously and surely controlled to reliably control the minute fuel. It is possible to suppress deterioration of fuel efficiency and fluctuations in the number of revolutions.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram of a gas engine heat pump air conditioning system to which the present invention is applied. This air conditioning system includes an outdoor unit 60 and a plurality of indoor units 61 (only one is shown in the figure). A gas engine 1 is provided in the outdoor unit 60, and a heat pump refrigerant cycle 2 driven by the gas engine 1.
Is formed between the outdoor unit 60 and the outdoor unit 61.

The gas engine 1 has an intake passage 4 connected to an air cleaner 3, and a mixer 5 is provided on the intake passage 4. A throttle valve 6 is provided on the downstream side of the gas mixing section of the mixer 5, and adjusts an amount of a mixture of outside air and gas fuel which is taken in from an intake port 18 and supplied through an air cleaner 3. A fuel supply pipe 7 is connected to a gas mixing section of the mixer 5 to form a gas mixture. On the fuel supply pipe 7, a gas fuel control valve 8 (main fuel control valve) for adjusting the flow rate of gas fuel supplied to the mixer 5 and a zero governor 9 for adjusting gas pressure to atmospheric pressure are provided. Is connected to a fuel gas tank (not shown). The gas fuel control valve 8 is feedback-controlled by the CPU as described later.

In the present embodiment, the intake passage 4 upstream of the zero governor 9 of the fuel supply pipe 7 and downstream of the mixer 5
Is provided, and a fuel correction control valve is provided on the fuel branch passage to perform a catalyst regeneration process as described later.

An exhaust pipe 12 is provided on the exhaust side of the gas engine 1. An exhaust gas catalyst 13 (in this embodiment, a NOx storage reduction catalyst) and an exhaust gas heat exchanger 1
4 and a silencer 15 and a drain separator 16 on the downstream side, and exhaust gas is discharged from an exhaust outlet 17. Drain separator 16 and silencer 15
The exhaust gas heat exchanger 14 is connected to the neutralizer 19, neutralizes the acidic drain water, and discharges the acidic drain water from the drain outlet 20 to the outside.

An oil tank 22 is connected to an oil pan 21 at the bottom of the gas engine 1, and oil is supplied by an oil supply pump 23. The oil circulates through the engine by an oil pump (not shown). Reference numeral 11 denotes an oil separator for separating oil in the blow-by gas.

Two compressors 25 are connected to a crankshaft (not shown) of the gas engine 1 via a clutch 24. Each compressor 25 is connected to a refrigerant inlet pipe 27 and a refrigerant outlet pipe 28 through which a refrigerant made of de-fluorocarbon gas or the like circulates. A flexible pipe 2 is provided in the refrigerant inlet pipe 27 and the refrigerant outlet pipe 28 around the compressor in order to arrange the pipes compactly and to absorb stress and vibration.
6 are interposed. An oil separator 29 is mounted on the refrigerant outlet pipe 28 side, and is connected to the four-way valve 30 on the downstream side. The oil separator 29 separates oil and liquid refrigerant from the compressed refrigerant gas, and returns them to the accumulator 35 through the return pipe 33. The four-way valve 30 has four ports a, b, c, and d, and the connection between the ports is switched during cooling and heating.

At the time of heating, as shown, port a and port b are connected, and port c and port d are connected. As a result, the compressed refrigerant gas discharged from the compressor 25 is condensed through the indoor heat exchanger 31, and the condensed heat is released into the room to heat the room. The condensed refrigerant is decompressed through the expansion valve 52 and evaporates through the outdoor heat exchanger 32 via the HIC 51. The evaporated refrigerant passes through the ports c and d of the four-way valve 30 and enters the accumulator 35 via the plate heat exchanger 34 or the bypass pipe 45. A sub-accumulator 46 is provided in parallel with the accumulator 35. The refrigerant of the accumulator 35 is the capillary tube 4
8, 49, 50 and the refrigerant inlet pipe 2 through the throttle 47 and the like.
7 sucks into the compressor 25.

Reference numeral 80 denotes a refrigerant pipe extending from the four-way valve 30 to the expansion valve 52 through the indoor heat exchanger 31.
Reference numeral 1 denotes a refrigerant pipe extending from the expansion valve 52 to the subcool outdoor heat exchanger 32a via the HIC 51, and reference numeral 82 denotes a refrigerant pipe which diverges from the subcool outdoor heat exchanger 32a, joins via the outdoor heat exchanger 32, and reaches the four-way valve 30. Refrigerant pipe until
Reference numeral 3 denotes a refrigerant pipe 81 from an intermediate portion of the refrigerant pipe 81 via an open / close valve 83a functioning as an electronic expansion valve when opened and the HIC 51.
It is a bypass pipe to the middle part of.

During cooling, the ports a and c of the four-way valve 30 are connected, and the ports b and d are connected. As a result, the compressed refrigerant gas is condensed in the outdoor heat exchanger 32 before passing through the ports a and c in reverse to the time of heating, passes through the expansion valve 52, evaporates in the indoor heat exchanger 31, and cools the room. Thereafter, the accumulator 3 passes through the ports b and d of the four-way valve 30.
Return to 5.

The subcool outdoor heat exchanger 32a includes:
It functions as a condenser for further supercooling the refrigerant condensed and liquefied in the three outdoor heat exchangers 32 arranged in parallel.

On the refrigerant pipe, HIC 51
This is a heat exchanger for reducing pressure loss for improving (refrigerant coefficient of performance). That is, when the required load on the outside of the room is small and the high-pressure refrigerant is bypassed to the low-pressure side refrigerant pipe 80 through the bypass pipe 83 during the cooling operation, the on-off valve 83a
Is opened and a desired throttle opening degree is reached, and the refrigerant which has been decompressed by the on-off valve 83a and has become low-temperature and low-pressure is subjected to heat exchange with the high-pressure and high-temperature liquid refrigerant by the HIC 51 to further supercool (subcool) the high-pressure side. On the low pressure side, it functions to assist the evaporation of the refrigerant.

The plate heat exchanger 34 is for heating the refrigerant introduced into the accumulator 35 with high-temperature engine cooling water in the middle of the piping. The plate heat exchanger 34 is provided with a bypass pipe 45,
COP is improved by reducing pressure loss during cooling.

The gas engine 1 is provided with a cooling water system 39, and cooling water is circulated by a cooling water pump 40. The cooling water sent by the cooling water pump 40 is supplied to the exhaust heat exchanger 14.
And is sent to the cooling jacket (not shown) of the engine by the second pump 41. A thermostat 42 is provided on the cooling water pipe on the outlet side from the engine to bypass the cooling water during a warm-up operation or the like. The cooling water system 39 is provided with a linear three-way valve 43 on the pipe on the engine outlet side, and a radiator 36 is provided in parallel with the outdoor heat exchanger 32 on the downstream side thereof. The radiator 36 is connected to a recovery tank 38. The linear three-way valve 43 allows the cooling water to flow to the radiator 36 side during cooling and dissipates heat by the fan 37 during cooling, flows to the plate heat exchanger 34 side through the branch pipe 44 during heating, and cools the high-temperature cooling water by heating the refrigerant. I do.
The amount of branching to the radiator 36 side and the plate heat exchanger 34 side can be adjusted and controlled.

FIG. 2 is a main part configuration diagram of a stationary gas engine applied to the air conditioning system of FIG. 1 and the like. The gas engine 100 has a piston 106 connected to a crankshaft 103, and is provided with an intake valve 115 and an exhaust valve 116 facing a combustion chamber 161 on the upper surface of the piston. These intake / exhaust valves are provided with intake-side and exhaust-side VVTs 1h, 1i, respectively. These V
The VTs 1h and 1i are hydraulic valves for changing the valve phase, and are used for improving the stability on the low speed side and improving the output on the high speed side. The crankshaft 103 is connected to the load 2A (compressor) via the electromagnetic clutch 5a.

The combustion chamber 161 has an intake passage 111 communicating with an air intake 117a through an air cleaner 117.
Is connected. A carburetor (or mixer) 118 is provided in the middle of the intake passage 111, and a throttle 119 is provided downstream thereof. Venturi 11 of vaporizer 118
The end of the fuel supply passage 162 is connected to 8a to form a fuel discharge port. The fuel supply passage 162 is connected to the fuel gas cylinder 11.
3, two solenoid on-off valves 121 serving as gas fuel supply sources, a zero governor (reducing valve) 122 for making the pressure of the fuel gas almost atmospheric pressure, and a main unit for adjusting the gas fuel supply amount. A fuel control valve 123a is provided.

A pressure sensor 130 is provided in a fuel supply passage 162 on the upstream side of the zero governor 122, and a fuel branch passage 163 branches to communicate with the intake passage 111 downstream of the throttle 119. This fuel branch passage 163
Is provided with a fuel correction control valve 123b composed of a linear duty solenoid valve (or an on / off valve) for controlling gas fuel supplied through this branch passage.

The solenoid on-off valve 121 on the fuel supply passage 162
And the main fuel control valve 123a and the fuel branch passage 163.
The upper fuel correction control valve 123b is connected to a control device 160 including a microcomputer having an operation control program, maps for various calculations, and the like, and is driven and controlled as described later.

Exhaust passage 112 communicating with combustion chamber 161
In addition, a NOx storage reduction catalyst 170 is provided, and an exhaust heat exchanger 127 using water as a medium is provided downstream thereof. 12
A cooling water temperature sensor 8 is connected to the control device 160 and controls the temperature of the cooling water of the engine by adjusting the amount of water to the exhaust heat exchanger 127 to prevent overheating.

The occlusion reduction catalyst 170 is connected to the exhaust heat exchanger 12
It is attached in front of 7 to prevent accumulation of condensed water in the exhaust gas when the engine is stopped or the like as a vertical installation structure. Reference numeral 172 denotes a water jacket for radiating the catalyst, and the exhaust heat exchanger 1
27 is connected to the cooling water channel. This water jacket 1
A catalyst cooling water control valve 171 connected to the control device 160 is provided on the cooling water channel 72 to control the amount of cooling water.
A catalyst heater 173 adjusts a catalyst activation temperature at the time of cold start or the like. 1 m is a temperature sensor for monitoring the catalyst temperature.

The control device controls the cooling water control valve 171 based on the detected catalyst temperature from the temperature sensor 1m so that the temperature of the catalyst does not become abnormally high.
In addition to adjusting the cooling water amount, when the catalyst activation temperature does not easily reach the temperature during cold weather or the like, the catalyst heater 173 is driven to maintain the activation temperature.

A first NOx sensor 1j is mounted upstream of the storage reduction catalyst 170 in the exhaust passage 112, and a temperature sensor 1m for monitoring the catalyst temperature is mounted immediately before the storage reduction catalyst 170. A second NOx sensor 1k is mounted in the exhaust passage 112 on the downstream side of the storage reduction catalyst 170. Each NOx sensor is capable of detecting _{O 2} together with NOx, also used as an oxygen concentration sensor.

The first NOx sensor 1j detects the oxygen concentration in the exhaust gas before passing through the catalyst and uses it for A / F control. The second NOx sensor 1k detects the NOx concentration in the exhaust gas after passing through the catalyst and uses it for storage reduction control, and detects the oxygen concentration and uses it for calibration of the oxygen concentration detection by the first NOx sensor.

It is also possible to calculate the amount of NOx absorbed by the storage reduction catalyst 170 based on the difference between the NOx concentrations detected by the first and second NOx sensors 1j and 1k.

An exhaust camshaft sensor 10a detects the phase of the exhaust valve 116. An intake side camshaft sensor 10b detects the phase of the intake valve 115 and is used for calculating the rotation speed. 124 is an ignition plug, 125 is an ignition unit, and 126 is an ignition coil.

An example in which the drive control method of the stationary gas engine having the above configuration is applied to a gas heat pump (GHP) type air conditioning system will be described.

The overall operation of the GHP system is performed according to a flowchart shown in FIG. 3 (details will be described later). At that time, the target rotation speed is determined in the air conditioning operation. The engine is operated according to the target rotational speed according to the flowchart shown in FIG.

First, the calculation of the throttle is performed. As shown in the flow chart of FIG. 5 (details will be described later), the throttle operation opening is determined by the deviation and displacement (differential value of deviation) between the required engine speed and the actual engine speed. , The engine level is calculated by a map calculation, and the opening / closing degree is determined by a flow according to the level.

Next, the operation of the fuel control valve is performed. When the operation of the fuel control valve has no abnormality in the catalyst control, as shown in the flowchart of FIG. calculated by the three-dimensional interpolation the oxygen concentration as a target from the map, the target value and the O ₂ sensor (NO in this embodiment
The deviation and displacement of the actual oxygen concentration obtained from the x-sensor are calculated using fuzzy calculations shown in FIGS.
The fuel control valve operation correction amount is determined from the engine level correction value shown in FIG.

When there is an abnormality in the catalyst control, as shown in FIG. 16, the basic opening of the fuel control valve is calculated by a three-dimensional interpolation from an emergency operation opening map which is set in advance so that the NOx emission value becomes, for example, 100 ppm. , And adds the fuel control valve operation correction amount corresponding to the engine level correction value shown in FIG. 13 to determine the operation opening.

Next, the ignition timing is calculated. As shown in the flowchart of FIG. 6 (details will be described later), the required ignition timing is calculated by three-dimensional interpolation from the map of FIG. 15 and corrected by the engine level. Determined by adding values. The boost axis data of the fuel control valve and the ignition timing map may use the throttle opening as a parameter.

In the engine drive control operation, the operation of the storage reduction catalyst 170 (FIG. 2) is controlled so as to repeat the storage operation and the reduction operation as shown in the flowchart of FIG.

That is, first, the fuel correction control valve basic opening F
hb is calculated as a duty ratio from the map of FIG. This is because this fuel correction control valve is not used only for the reduction action, and when performing extremely low-speed operation, the main fuel control valve alone cannot secure the minimum minute flow rate. This is because when the valve opening is 0, the flow rate from the fuel correction control valve is required according to this map.

Next, it is determined whether the current control state is the storage operation or the reduction operation. In the case of the occlusion operation, the basic opening degree of the fuel correction control valve is only Fhb, and reaches the maximum reduction time calculated by the three-dimensional interpolation in the map of FIG.
The operation is performed until the NOx sensor detects the maximum allowable NOx that has been three-dimensionally interpolated in the maximum allowable NOx value map of FIG.

When this operation is completed, the operation shifts to the reduction operation. In the reduction operation, as shown in FIG. 20, a three-dimensional interpolation of a reduction opening map of the fuel correction control valve, which is set in advance so as to obtain the same torque as the torque currently being operated in a rich state above the stoichiometric air-fuel ratio, is performed. The operation is performed at an opening obtained by adding this opening and Fhb. That is, as shown in the torque characteristic curve of FIG. 26, the state of the air-fuel ratio λ2 from the storage operation state in which the lean burn operation is performed in the lean state of the air-fuel ratio λ1 to the same torque on the rich side as the torque in this operation state By doing so, a reducing atmosphere can be obtained without causing torque fluctuation. As a result, the torque becomes the same even if the storage reduction cycle is repeated, so that the catalyst can be regenerated without causing large rotation fluctuation, and the stable N
The Ox removal function can be maintained.

The above reduction operation is performed until the NOx value detected by the NOx sensor falls below the value obtained by performing three-dimensional interpolation on the maximum reduction NOx value map shown in FIG. 22, and the time required for this operation is shown in FIG. If the time exceeds the map time, it is determined that the catalyst has been physically damaged or the NOx sensor has failed, and an abnormality flag is set. This flag is not cleared until the next time the engine is started.
While this flag is set, the fuel control valve performs the above-described operation, stops the catalyst control, issues a warning to the user, and notifies the user that the emergency operation is being performed.

In this embodiment, the fuel correction opening is learned. The learning of the correction opening degree is performed by measuring the maximum swirling amount Rmax of the engine speed and the time t required for the swirling at the same time as the start of the reduction operation. At the end of the reduction operation, a corrected output value is calculated according to the fuzzy calculation rules shown in FIGS. At this time, the swirling state of the engine speed is as shown in FIG.
The correction output value is calculated based on Rmax and ΔRR in the drawing. This corrected output value is added to the data at the current position in the fuel correction control valve opening degree map shown in FIG. 20, and the map data is rewritten. By repeating this, the number of revolutions which has been excessively increased immediately after the rich operation does not gradually increase, and more stable engine operation can be realized.

Hereinafter, the operation control flowcharts of FIGS. 3 to 7 will be described in detail. FIG. 3 is a flowchart showing the driving operation of the entire system. The processing operation in each step of the driving operation flow is as follows. S1: Perform initial settings of a microcomputer, a GHP (gas heat pump) communication system, each sensor, an actuator, and the like while being connected to a power supply via a breaker (or a main switch) or the like. S2: Check whether the remote controller has been pressed. When the remote control is turned on, power is supplied to each device in the system, and the operation starts.

S3: One of the two electromagnetic on-off valves 121 (FIG. 2) is turned on, and the ventilation fan is driven to purge the engine room for, for example, 30 seconds. At this time, the throttle and the fuel control valve motor (main fuel control valve 123
In the case of a), an operation for finding the origin is also performed, and after the zero point is set, the operation is performed to the initially set opening degree. The ignition timing is set to an initial required ignition timing. S4: The other of the solenoid on-off valves 121 is turned on, the ignition power is turned on, and the cell motor is operated.

S5: It is determined whether or not the engine has started by checking from the detected data of the engine speed whether or not the engine speed exceeds the startup completion speed. S6: When the engine starts, the starter motor is turned off. After this point, various controls of the engine shown in a flowchart described later are started. S7: The initialization operation is performed before the clutch is connected. In this initialization operation, high-speed operation is performed for about 40 seconds at a stoichiometric air-fuel ratio in order to prevent carbon from accumulating in valves and the like and to completely reduce and purify the catalyst.

S8: The electromagnetic clutch 5a (FIG. 2) is turned on.
(Connection) to connect the engine 100 and the compressor 2A. At this time, the throttle and the fuel control valve motor perform a clutch connection correction operation. This is an operation for performing an offset operation for preventing a drop in the engine speed due to a sudden load change when the clutch is engaged. . The control amount of the offset operation is obtained by multiplying the refrigerant high pressure by a correction coefficient for each of the throttle and the fuel control valve.

S9: The engine is operated normally according to the flowchart described later. S10: At the same time as performing the air conditioning control, the engine target speed is calculated. In this case, the target rotation speed is set so that the target of the refrigerant low pressure is, for example, 4 kgf / m ² (1 kgf / m ^{2 ≒} 9.8 Pa) in the cooling mode, and the target of the refrigerant high pressure is, for example, 20 kgf / m in the heating mode. to set the target rotational speed so as to m ^2. In both modes, the difference in displacement between the room temperature and the set temperature of the remote controller and the amount of displacement are correction values.

S11: It is checked whether or not there is a request to stop the engine due to a remote control OFF, a thermo OFF when the set room temperature is reached, a sensor or other abnormality, and the like. S12: When there is a request to stop the engine, the clutch is turned off for about 3 seconds at a stoichiometric air-fuel ratio in order to completely reduce and purify the catalyst, and then the clutch is turned off. S13: As the engine stop processing, the ignition is cut, and the throttle and the fuel control valve opening are operated to the engine stop opening. In the case of a stop due to an error, an error is displayed and the process does not shift to the next start until a countermeasure is taken.

S14 to S19: Engine start failure processing. That is, first, it is checked whether or not the starter motor has reached a predetermined stop time (time during which continuous operation can be performed, for example, 7 seconds) (step S14). Increase (step S
15) The number of restart operations is compared with a predetermined value (for example, 5 times) (step S16). If it is equal to or more than the predetermined value, a failure in starting operation is displayed (step S17). The process is performed (Step S18), and the process returns to the purge process (Step S9).

FIG. 4 is a flowchart of the engine control. The operation of each step is as follows. S1: Start an engine control subroutine after engine startup. S2: Check whether there are signals from the camshaft sensors 10a and 10b (FIG. 2). S3: The crank position is cleared using the cam position as the crank reference point. S4: The required throttle opening for performing the later-described throttle control is calculated using the maps of FIGS. The required throttle opening degree Tref is represented by Tref = To + Δf (ΔR, ΔR ′, Δt) dt To: initial throttle value f (ΔR, ΔR ′, Δt): required operation amount calculated by map.

S5: A required fuel control valve opening for controlling a fuel control valve (main fuel control valve 123a) described later is calculated. S6: An ignition request timing for performing ignition timing control described later is calculated. S7: Check whether there is a signal from the crank sensor 9a (FIG. 2) for detecting the crank position. This signal is
The operating angle is detected by detecting the ring gear of the crankshaft. S8: The crank angle is added.

S9: It is checked whether the crank angle calculated in step S8 is the required ignition timing of each cylinder. S10: If the crank angle is the required ignition timing, the ignition is output. S11: Check whether the throttle motor operation time has elapsed. This time is detected by a timer of the CPU (control device 160). S12: The throttle motor is operated in unit steps. However, it does not operate when the target has been reached.

S13: It is checked whether the operation time of the fuel control valve motor has elapsed. This time is detected by a timer of the CPU (control device 160). S14: Operate the fuel control valve motor in unit steps. However, if the target is met, it will not operate. S15: Subroutine control of the storage reduction catalyst described below is performed.

FIG. 5 is a flowchart of the throttle control subroutine. The operation of each step is as follows. S1: Start a subroutine called when a camshaft signal is input. S2: The target rotational speed Rr of the GHP system is calculated. S3: The rotation speed Re is calculated from the camshaft signal time. S4: A deviation ΔR of the engine speed is calculated. ΔR = Re−Rr

S5: The displacement ΔR ′ of the engine speed is calculated. ΔR ′ = ΔR / dt S6: An engine level L is calculated by executing a three-dimensional surface interpolation operation using ΔR and ΔR ′ as inputs. The engine level is obtained from the map shown in FIG. S7: From the calculated engine level L to the level in FIG.
The throttle operation amount Tc is calculated based on the operation amount conversion map. S8: Output a throttle request operation signal to the actuator. S9: End the subroutine.

FIG. 6 is a flowchart of the fuel control and the ignition control. The operation of each step is as follows. S1: Start a subroutine called when a camshaft signal on the intake side is input. S2: Check whether there is an abnormality in the catalyst control. S3: The target oxygen concentration Or is calculated from the three-dimensional map of FIG. 8 based on the engine speed and the boost (negative intake pressure). S4: Sensor for detecting O ₂ and NOx (first NOx
The current oxygen concentration Oe is calculated from the sensor 1j).

S5: The oxygen concentration deviation ΔO is calculated. ΔO = Oe−Or S6: Calculate the oxygen concentration displacement ΔO ′. ΔO ′ = ΔO / dt S7: Based on the membership function of FIG. 9 and the rule of FIG. 10, a fuzzy operation is performed with ΔO and ΔO ′ as inputs, and the fuel control valve 123a is determined using the map of FIG.
Is calculated. S8: The fuel correction amount Fc is calculated from the engine level.
This correction amount is obtained from the map of FIG.

S9: The operation amount T of the fuel control valve is calculated. S10: A signal of the required operation amount T is issued to the actuator of the fuel control valve. S11: The basic ignition timing It is calculated from the engine speed and the boost based on the map shown in FIG. S12: An ignition timing correction value Ic is calculated from the engine level. This correction value Ic is obtained from the map shown in FIG.

S13: The ignition timing I is calculated. S14: Output an ignition timing request operation signal to the ignition coil. S15: When there is an abnormality in the catalyst control, the required opening is calculated from the map in FIG. 16 using the fuel control valve opening as the emergency opening. S16: End the subroutine.

FIG. 7 is a flowchart showing the operation of the fuel correction control valve 123b. The operation of each step is as follows. S1: Fuel correction control valve 123b using the map of FIG.
Is calculated. S2: NOx sensor (second NOx sensor 1 on the downstream side of the catalyst)
k (FIG. 2)), the current NOx emission concentration Nr is calculated. S3: Determine the catalyst operation mode. The mode value = 0 indicates that the storage operation is being performed, and the non-zero value indicates that the reduction operation is being performed. S4: Maximum allowable NOx representing the maximum value of NOx emission concentration
The value Nq is calculated by a three-dimensional map calculation including the engine speed and the boost using the map of FIG.

S5: The current NOx emission concentration is the maximum allowable N
Check if the Ox value is not exceeded. If it exceeds, the occlusion operation ends. S6: Subtract the timer counter. S7: Check whether the storage completion time has elapsed. The storage operation has a time upper limit of the map solution shown in FIG. This is emergency control when the current NOx emission concentration cannot be determined due to damage to the sensor or the like. S8: The return time is calculated from the map of FIG.

S9: The catalyst operation mode is set to 1 as a procedure for completing the occlusion. S10: The opening degree Fhr of the fuel correction control valve required for the reduction operation is calculated from the map of FIG. S11: Operate the fuel correction control valve as an output Fh ← Fhb + Fhr based on the basic opening Fhb (calculated in step S1) and the reduction opening Fhr (calculated in step S10). S12: If the reduction operation is being performed, the reduction timer counter is decremented.

S13: It is checked whether the maximum time of the reduction operation has elapsed. The reduction operation has the time upper limit value of the map solution shown in FIG. This is emergency control when the current NOx emission concentration cannot be determined due to damage to the sensor or the like. At this time, an error check is performed. S14: The maximum allowable NOx value Nf representing the maximum value of the NOx emission concentration in the reduction operation is calculated from the map of FIG. 22 by a three-dimensional map calculation including the engine speed and the boost.

S15: It is checked whether the current NOx emission concentration exceeds the maximum allowable NOx value. If it exceeds, the reduction operation ends. S16: Clear the catalyst abnormality flag and the abnormality counter. S17: The catalyst operation mode is set to 0 as a procedure for completing the reduction. S18: The opening degree of the fuel correction control valve required for the storage operation is calculated from the map of FIG. 19, and the timer counter for the storage operation is set.

S19: Output fuel correction control valve Fh ← Fh
b (calculated in step S1). S20: If the maximum return time has elapsed, an abnormality counter is added. S21: Check whether the abnormality counter has exceeded the maximum time 16 times or more. If it is 16 times or more, the catalyst is determined to be damaged. S22: If the catalyst is damaged, a catalyst abnormality flag is set.

[0075]

As described above, according to the present invention, by controlling the opening of the fuel correction control valve provided in the fuel branch passage by the control device, the lean state at the time of NOx absorption by the catalyst is obtained on the torque characteristic curve. The fuel is supplied into the intake passage so that the air-fuel ratio becomes a rich state that can obtain the same torque as the air-fuel ratio of the air-fuel ratio, thereby suppressing the torque fluctuation and the rotation speed fluctuation. At this time, with the main fuel control valve in the gas fuel supply passage performing fuel supply to obtain a rotation speed corresponding to the required load on the system side and maintaining a constant rotation, the fuel supply passage upstream of the pressure reducing valve in the fuel supply passage is maintained. Since high-pressure gas fuel is supplied from the fuel branch passage into the intake passage on the downstream side of the venturi, where the intake negative pressure is large, gas fuel is instantaneously supplied due to a large pressure difference, resulting in a rich atmosphere necessary for catalyst regeneration in a short time, resulting in poor fuel economy. Can be suppressed.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a GHP air conditioning system to which the present invention is applied.

FIG. 2 is a configuration diagram of a gas engine according to the embodiment of the present invention.

FIG. 3 is a flowchart showing the operation of the entire air conditioning system according to the embodiment of the present invention.

4 is a flowchart of an engine control operation of the air conditioning system of FIG.

FIG. 5 is a flowchart of a throttle control operation of the engine of FIG. 4;

FIG. 6 is a flowchart of fuel control and ignition control of the engine of FIG. 4;

FIG. 7 is a flowchart of fuel correction control of the engine of FIG. 4;

FIG. 8 is a view showing a map of a target oxygen concentration of the engine.

FIG. 9 is a diagram of a membership function of air-fuel ratio fuzzy control.

FIG. 10 is a diagram showing a rule of air-fuel ratio fuzzy control.

FIG. 11 is a diagram showing a map of an engine level and a fuel control valve opening correction value;

FIG. 12 is a diagram showing an engine rotation level map.

FIG. 13 is a diagram showing a conversion map between an engine level and an operation amount.

FIG. 14 is a diagram showing a conversion map between an engine level and an operation time.

FIG. 15 is a diagram showing an ignition timing map.

FIG. 16 is a diagram showing a fuel control valve emergency operation opening degree map;

FIG. 17 is a diagram showing a map of a fuel correction control valve opening degree;

FIG. 18 is a diagram showing an occlusion completion time map.

FIG. 19 is a diagram showing a maximum return time map.

FIG. 20 is a diagram showing a map of a reduction opening degree of the fuel correction control valve.

FIG. 21 is a diagram showing a map of a maximum allowable NOx value.

FIG. 22 is a view showing a map of a maximum reduced NOx value.

FIG. 23 is a diagram showing a membership function of an antecedent input used in learning control.

FIG. 24 is a diagram showing rules used in learning control.

FIG. 25 is a diagram showing a membership function of a correction output consequent part used in learning control.

FIG. 26 is a graph showing emission, fuel consumption, and torque characteristics of the gas engine according to the present invention.

FIG. 27 is an explanatory view of a state in which the engine speed is increased.

[Explanation of symbols]

1: gas engine, 2: refrigerant cycle, 3: air cleaner, 4: intake passage, 5: mixer, 6: throttle valve,
7: fuel supply pipe, 8: fuel control valve, 9: zero governor, 1
0: open / close valve, 11: oil separator, 12: exhaust pipe,
13: catalyst, 14: exhaust heat exchanger, 15: silencer,
16: drain separator, 17: exhaust outlet, 18: intake port, 19: neutralizer, 20: drain outlet, 21: oil pan, 22: oil tank, 23: oil supply pump, 2
4: clutch, 25: compressor, 26: flexible tube, 2
7: refrigerant inlet pipe, 28: refrigerant outlet pipe, 29: oil separator, 30: four-way valve, 31: indoor heat exchanger, 32: outdoor heat exchanger, 33: return pipe, 34: plate heat exchanger,
35: accumulator, 36: radiator, 37: fan, 38: recovery tank, 39: cooling water system, 40:
Cooling water pump, 41: second pump, 42: thermostat, 43: linear three-way valve, 44: branch pipe, 45: bypass pipe, 46: sub-accumulator, 47: throttle, 48,
49, 50: capillary tube, 51: HIC, 5
2: expansion valve, 60: outdoor unit, 61: indoor unit, 73: exhaust pressure sensor, 75: compressor temperature sensor, 76: cooling water temperature sensor, 77: high pressure side refrigerant pressure sensor, 100: gas engine, 103: crank Axis 1,
06: piston, 108: water jacket, 11
1: intake passage, 113: gas cylinder 115: intake valve, 116: exhaust valve, 117: air cleaner 124: spark plug, 125: ignition unit, 126:
Ignition coil, 127: exhaust gas heat exchanger, 128: cooling water temperature sensor, 112: exhaust passage, 160: control device, 1
61: combustion chamber, 122: zero governor (pressure reducing valve), 12
1: electromagnetic gas valve, 123a: main fuel control valve, 123
b: fuel correction control valve, 163: fuel branch passage, 162:
Fuel supply passage, 170: storage reduction catalyst, 171: catalyst cooling water control valve, 172: water jacket for radiating catalyst,
173: catalyst heater,

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F02D 41/04 325 F02D 41/04 325Z F-term (Reference) 3G091 AA06 AA12 AA19 AB06 BA03 BA14 BA32 BA33 CA03 CA07 CA08 CB01 CB05 CB07 CB08 DA01 DA02 DA03 DB06 DB07 DB09 DB10 DB13 DC01 DC02 EA00 EA01 EA07 EA16 EA18 EA30 EA32 EA33 EA34 FA02 FA06 FB02 FB10 FB12 FC02 FC06 FC07 HA36 HA37 HA38 HA42 3G092 AA01 AB04 A03 A04 A03 A04 DE12S DE12Y DE13S DE13Y DE14S DE14Y DG10 EA01 EA02 EA03 EA04 EA05 EA06 EA07 EA09 EA17 EA21 3G301 HA15 JA15 JA25 JA33 JB09 LA03 LB06 LB07 MA01 NA04 NA06 NA07 NA08 ND01 ND21 PD02 PD02 PD02 PD08 PD15B PE01A PE01B PE03A PE03B PE08A PE08B PE10A PE10B PF13A PF13B

Claims (3)

[Claims] 1. A venturi section is provided in an intake passage communicating an air intake and a combustion chamber, a gas fuel supply path is connected to the venturi section, and a main fuel control valve and a pressure reducing valve are provided in the gas fuel supply path. A fuel branch passage branching from a gas fuel supply passage upstream of the pressure reducing valve and connected to an intake passage downstream of the venturi section; a fuel correction control valve provided in the fuel branch passage; A NOx storage reduction catalyst is provided in the communicating exhaust passage, a NOx sensor for detecting the NOx concentration is provided in the exhaust passage downstream of the NOx storage reduction catalyst, and the fuel correction control valve is opened according to the detected concentration of the NOx sensor. A stationary gas engine comprising a control device for controlling the degree. 2. The stationary gas engine according to claim 1, wherein the control device is configured to increase the opening of the fuel correction control valve as the detected concentration of NOx increases. . 3. An engine speed sensor, a throttle provided downstream of the venturi section, an opening adjustment means for the throttle, and the control device is provided when the throttle opening is small or when the engine speed is low. 2. The stationary gas engine according to claim 1, wherein the fuel correction control valve of the branch passage is opened when the engine is at a low speed.