JP2003227415A - Operation control method for gas engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an operation control method for a gas engine which stabilizes an output of the gas engine even if gas having different components and combustion characteristics is used as a fuel. <P>SOLUTION: The operation control method for a gas engine of a gas heat pump type air-conditioner, a refrigeration cycle is formed by circulating a coolant by cooperation of the gas engine using gas as a fuel and a compressor using the gas engine as a driving source. A detection of lean limit of the gas engine is carried out at a predetermined operation condition at the time of steady operation of the gas engine and the kind of the gas is specified by the result. The operation condition is corrected corresponding to the kind of the specified gas and the gas engine is continuously operated by the corrected operation condition. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas engine operation control method for a gas heat pump type air conditioner in which a compressor for circulating a refrigerant is driven by using a gas engine as a drive source, and more particularly, to a method of controlling the number of components and combustion characteristics. Kind of note that it is possible to use different kinds of gas as fuel, and to obtain a stable output even when the same kind of gas has different components and combustion characteristics due to differences in lots etc. Is.

[0002]

2. Description of the Related Art A gas heat pump type air conditioner (hereinafter abbreviated as "GHP") using a gas engine as a power source of a compressor can use city gas or the like, which is relatively inexpensive, as fuel. The running cost does not increase unlike an air conditioner that uses an electric motor as a power source (hereinafter abbreviated as “EHP”).

Further, in the GHP, the heat (so-called waste heat) of the high-temperature exhaust gas or engine cooling water discharged from the gas engine can be utilized as a heat source for the refrigerant during heating operation, which is excellent. The heating effect can be obtained, and the energy utilization efficiency can be improved as compared with EHP.

Further, in the GHP, the defrosting operation of the outdoor heat exchanger required during the heating operation, so-called defrosting operation, can be carried out by utilizing the waste heat of the gas engine, so that the defrosting operation in the EHP is performed. ,
It is not necessary to stop the heating operation and temporarily perform the cooling operation to remove the frost from the outdoor heat exchanger, and continuous operation is possible.

[0005]

However, in the above-mentioned GHP, as shown in FIGS. 6 and 7, the gas (13A, 5C,
Since the composition and combustion characteristics differ depending on the type of liquefied petroleum gas, etc., the calorific value and the burning rate differ depending on the type of gas used, which may make it difficult to start the gas engine under the same operating conditions. In other words, the type of gas is standardized by the MCP and Woppe index, as shown in FIG.
As shown in the example of FIG. 7, the compositions and the like are generally different even if they are of the same type (for example, 13A). In addition, MCP
Is the maximum burning rate (Maximum Combust)
Ion Potential), and the Woppe index is a value obtained by dividing the total calorific value by the square root of specific gravity.

Further, even if the same kind of gas (for example, 13A) has different components and combustion characteristics, the calorific value and the combustion speed differ depending on the kind of gas used, and the output of the gas engine changes under the same operating conditions. May occur, the exhaust gas components (NOx, CO, etc.) may change, knocking may occur, and the operation may become unstable. By the way, in the case of GHP 20 horsepower equivalent, the gas consumption is 5
^{C; 15m 3 / h, 13A} ; 5m 3 /h,LPG;2.5
It will be 5 m ³ / h.

The present invention has been made in view of the above-mentioned conventional problems, and it is possible to use several kinds of gases having different components and combustion characteristics as fuels, and the same components and combustion characteristics are different. It is an object of the present invention to provide a gas engine operation control method capable of stabilizing the output even when various kinds of gas are used as fuel.

[0008]

The present invention employs the following means in order to solve the above problems. In other words, the invention according to claim 1 forms a refrigeration cycle by circulating a refrigerant by cooperation of a gas engine that uses gas as a fuel and a compressor that uses the gas engine as a drive source, and discharges the gas from the gas engine. A method for controlling operation of a gas engine of a gas heat pump type air conditioner configured to recover the generated waste heat to engine cooling water and to heat the refrigerant by the engine cooling water to increase heating capacity. At the time of starting, the gas engine is started under predetermined operating conditions, it is determined whether the gas engine is started, the type of gas is specified based on the result, and the initial operation is performed according to the specified type of gas. It is characterized in that the gas engine is continuously operated under the conditions or the corrected operating conditions. According to the operation control method of the gas engine of the present invention, it is possible to use several kinds of gases having different components and combustion characteristics as the fuel of the gas engine.

The invention according to claim 2 is the operation control method for a gas engine of a gas heat pump type air conditioner according to claim 1, wherein the operating conditions are a fuel valve opening, an ignition timing, and a throttle opening. , And the number of rotations of the starter are at least one or more.
According to the operation control method of the gas engine of the present invention,
Set the fuel valve opening, ignition timing, throttle opening, and starter speed to predetermined values to start the gas engine,
The type of gas is specified by determining whether or not the gas can be started.

According to a third aspect of the present invention, a refrigeration cycle is formed by circulating a refrigerant through cooperation of a gas engine that uses gas as a fuel and a compressor that uses the gas engine as a drive source. A method of controlling the operation of a gas engine of a gas heat pump type air conditioner configured to collect exhausted waste heat in engine cooling water and to heat a refrigerant by the engine cooling water to increase heating capacity, During normal engine operation, the lean limit of the gas engine is detected under specified operating conditions, the type of gas is specified based on the result, and the operating conditions are corrected according to the specified type of gas, and the corrected operation is performed. It is characterized by continuously operating the gas engine depending on the conditions. According to the operation control method for a gas engine according to the present invention, the type of gas is specified by detecting the lean limit of the gas engine under predetermined operating conditions, and the operating conditions are corrected according to the specified type of gas. As a result, a stable output and exhaust gas composition of the gas engine can be obtained.

The invention according to claim 4 is the method for controlling the operation of the gas engine of the gas heat pump type air conditioner according to claim 3, wherein the predetermined operating conditions are a fuel valve opening degree, an ignition timing, and a throttle. It is characterized in that at least one or more is selected from the group selected from the opening degree, and the operating condition to be corrected is one or both of the fuel valve opening degree and the ignition timing. According to the operation control method of the gas engine according to the present invention, the fuel valve opening degree, the ignition timing, and the throttle opening degree are set to predetermined values, the lean limit of the gas engine is detected, and the type of gas is specified. By correcting the fuel valve opening degree and the ignition timing to predetermined values according to the specified gas type, a stable output of the gas engine can be obtained.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention shown in the drawings will be described below. FIG. 1 shows a gas heat pump type air conditioner used for implementing a gas engine operation control method according to the present invention. The gas heat pump type air conditioner comprises an indoor unit 1 and an outdoor unit 10. Is equipped with.

The indoor unit 1 functions as an evaporator that evaporates the low-temperature low-pressure liquid refrigerant during the cooling operation to remove heat from the indoor air (indoor air), and condenses and liquefies the high-temperature high-pressure gas refrigerant during the heating operation. The indoor heat exchanger 1a functions as a condenser that warms the indoor air. In the illustrated example, the throttle mechanism 1b is provided for each indoor heat exchanger 1a.

The outdoor unit 10 is divided into two large component parts, and is a first component part that forms a refrigerant circuit together with the indoor unit with a compressor, an outdoor heat exchanger and the like as the center. And a gas engine section, which is a second component section including a gas engine for driving the compressor, and devices associated therewith.

The refrigerant circuit section of the outdoor unit 10 includes a compressor 11, an outdoor heat exchanger 12, a water heat exchanger 13, an accumulator 14, a receiver 15, an oil separator 16, a throttle mechanism 17, a four-way valve 18, and a solenoid valve 19. , A check valve 20, an operation valve 21 and the like.

The compressor 11 is a gas engine GE which will be described later.
The low temperature low pressure gas refrigerant sucked by either the indoor heat exchanger 1a or the outdoor heat exchanger 12 is compressed and discharged as a high temperature high pressure gas refrigerant. As a result, during the cooling operation, the refrigerant can radiate heat to the outside air through the outdoor heat exchanger 12 even when the outside air temperature is high. Further, during the heating operation, it becomes possible to apply heat to the indoor air through the indoor heat exchanger 1a.

The outdoor heat exchanger 12 functions as a condenser that condenses and liquefies the high-temperature and high-pressure gas refrigerant to radiate heat to the outside air during the cooling operation, and evaporates the low-temperature and low-pressure liquid refrigerant to remove heat from the outside air during the heating operation. Functions as an evaporator. That is, the outdoor heat exchanger 12 performs a function opposite to that of the indoor heat exchanger 1a during each of the heating and cooling operations.

The outdoor heat exchanger 12 is installed adjacent to a radiator 33 of the gas engine GE which will be described later. The radiator 33 is a heat exchanger that exchanges heat with the outside air to cool the engine cooling water of the gas engine GE.

The water heat exchanger 13 is provided for the refrigerant to recover heat from the engine cooling water of the gas engine GE which will be described later. That is, during the heating operation, the refrigerant can not only rely on the heat exchange in the outdoor heat exchanger 12 but also recover the waste heat from the engine cooling water of the gas engine GE. Can be increased.

The accumulator 14 is provided to store the liquid component contained in the gas refrigerant flowing into the compressor 11. The receiver 15 is provided for gas-liquid separation of the refrigerant liquefied by the heat exchanger functioning as a condenser, and storing excess refrigerant in the refrigeration cycle as liquid. The oil separator 16 is provided to separate the oil contained in the refrigerant and return it to the compressor 11.

The throttle mechanism 17 is for decompressing and expanding the condensed high-temperature high-pressure liquid refrigerant into a low-temperature low-pressure liquid refrigerant. In the illustrated example, a constant pressure type expansion valve, a temperature type expansion valve and a capillary tube are properly used as the throttle mechanism 17 according to the purpose.

The four-way valve 18 is provided in the refrigerant pipe 2 and selectively switches the flow path and flow direction of the refrigerant. The four-way valve 18 is provided with four ports D, C, S and E,
The port D is connected to the discharge side of the compressor 11, the port C is connected to the outdoor heat exchanger 12, the port S is connected to the suction side of the compressor 11, and the port E is connected to the indoor heat exchanger 1a by refrigerant pipes 2, respectively. .

The gas engine section is provided with an exhaust gas system and an engine oil system (not shown) in addition to the cooling water system and the fuel intake system, centering on the gas engine GE. The gas engine GE is connected to the compressor 11 installed in the refrigerant circuit by a shaft or a belt, and the driving force is transmitted to the compressor 11 via the shaft or the belt when the gas engine GE is driven. .

The cooling water system 30 is provided with a water pump 31, a reservoir tank 32, a radiator 33, etc., and a gas engine GE is supplied by engine cooling water around a circuit (indicated by a broken line) constituted by connecting these components by piping. Is a system for cooling.

The water pump 31 is provided to circulate the cooling water of the gas engine GE in the circuit. The reservoir tank 32 is for temporarily storing an excess of the cooling water flowing through this circuit, or for supplying the cooling water when the cooling water is insufficient in the circuit. The radiator 33 is configured integrally with the outdoor heat exchanger 12, and is provided to release the heat taken by the engine cooling water from the gas engine GE to the outside air.

The cooling water system 30 is provided with an exhaust gas heat exchanger (exhaust gas heat exchanger) 34 in addition to the above-mentioned structure.
This is provided to recover the heat of the exhaust gas discharged from the gas engine GE to the engine cooling water.
Further, the cooling water system 30 is provided with the water heat exchanger 13 described above, and is arranged so as to extend over both the refrigerant circuit unit and the cooling water system 30. Therefore, during heating operation, the engine cooling water not only takes heat from the gas engine GE, but also recovers heat from the exhaust gas, and the recovered heat passes through the water heat exchanger 13 from the engine cooling water. It is a mechanism that is given to the refrigerant. The cooling water system 3
The flow rate control of the engine cooling water at 0 is performed by the flow rate control valves 35A and 35B provided at two locations.

The fuel intake system 40 includes a gas regulator 4
1, a gas solenoid valve 42, a gas connection port 43, etc., and is a system for supplying gas (liquefied natural gas (LNG)) or the like as fuel to the gas engine GE. Gas regulator 41
Is provided for adjusting the delivery pressure of the gas fuel supplied from the outside via the gas solenoid valve 42 and the gas connection port 43. The gas whose pressure is adjusted by the gas regulator 41 is mixed with the air sucked from the intake port (not shown) and then supplied to the combustion chamber of the gas engine GE.

Now, the gas engine GE of the gas heat pump type air conditioner having the above-described structure is provided with a control unit (hereinafter referred to as "ECU") 120 shown in FIG.
Driving is controlled by. In FIG. 2, 122 is an ignition device, 123 is an intake pipe, 124 is a throttle valve, 12
5 is a fuel valve, and 126 is a negative pressure sensor for detecting the intake pipe negative pressure Pb. The detection signal of the negative pressure sensor 126 is the ECU 1
20 is input to the ECU 120, and the ECU 120 determines the intake pipe negative pressure Pb (al..ak) based on the map 100 as shown in FIG.
・ ・ An) and engine speed Ne (bl ・ ・ bk)
The optimum combination of ignition timing Igt and fuel valve opening degree Gf corresponding to bn) is calculated, and the ignition device 122 and the fuel valve 125 are controlled so as to be the values. In this case, several kinds of gases having different components and combustion characteristics can be used as fuels, but under the same operating conditions, it may be difficult to start the gas engine GE depending on the kind of gas. Therefore, according to FIG. Is determined, the gas type is specified, and the operating condition is corrected according to the specified gas type.

Specifically, the operating conditions of the gas engine GE (fuel valve opening (Gf), ignition timing (Igt), throttle opening (θth), and starter rotation speed (Vst)) are set to constant values. Set the gas engine G under the operating conditions
E is started, and it is determined whether or not the gas engine GE is started.

When the gas engine GE is started, it is presumed that the type of gas corresponds to the operating conditions. On the other hand, when the gas engine GE has not started, the operating conditions (fuel valve opening (Gf), ignition timing (Igt), throttle opening (θth), and starter speed (Vst)) are corrected, When the gas engine GE is restarted under the corrected operating conditions to determine whether or not it can be started, and when the gas engine GE is started, it is estimated that the gas is the type of gas corresponding to the corrected operating conditions.

If the gas engine GE does not start even under these corrected operating conditions, the operating conditions (fuel valve opening (Gf), ignition timing (Igt), throttle opening (θth), and starter rotation are set. (Vst) is further corrected, the gas engine GE is restarted under the corrected operating conditions to determine whether or not the engine can be started, and by repeating such a process, the type of gas can be specified. Become. Note that the specification of the gas type and the correction to the operating condition according to the specified gas type are performed by the ECU 120 shown in FIG.

Therefore, even if several kinds of gases having different components and combustion characteristics are used as the fuel of the gas engine GE, the gas engine GE can be started under the operating condition corresponding to the kind of the gas.

Next, since the components and combustion characteristics are different even for the same type of gas, when the gas engine GE is operated under the same operating conditions, the calorific value and the combustion speed are different and the output changes. Or exhaust gas components (NOx, CO, etc.)
Change or knocking occurs. Therefore, the operating conditions are corrected according to FIG. 4, and the gas engine GE is continuously operated under appropriate operating conditions.

Specifically, the gas engine GE is operated under predetermined operating conditions ((fuel valve opening (Gf), ignition timing (Igt),
Throttle opening (θth) and starter speed (Vs
t)), the engine is started at a constant rotational speed (Ne) and load (refrigerant high pressure (HP), refrigerant low pressure (LP)), and the throttle opening (θth) is fixed to gradually throttle the fuel. Detects the rotational fluctuation or the combustion pressure fluctuation and detects the lean limit of gas.

Then, using a lean limit control map (see FIG. 5) corresponding to the kind of gas obtained in advance, the kind of gas is estimated from the control map and the detected lean limit, and the estimated gas is used. The operating conditions (fuel valve opening (Gf) and ignition timing (Igt)) are corrected to the operating conditions (fuel valve opening (Gf) and ignition timing (Igt)) according to the above, and the gas engine is corrected by the corrected operating conditions. Run the GE. By detecting and operating the lean limit, it is possible to improve thermal efficiency and reduce NOx in exhaust gas components.

Therefore, the same kind of gas (13A, 5C)
Etc.), the gas engine GE can be operated under appropriate operating conditions according to the type of the gas even if the gas having different components and combustion characteristics is used as the fuel for the gas engine GE. The output of the gas engine GE does not change, the exhaust gas components (NOx, CO, etc.) do not change, and knocking does not occur, and a stable output can be obtained.

In the above, the case where the engine fuel is gas has been described. However, it goes without saying that the present invention can also be used as a method for controlling the operation of an engine that uses liquid as fuel. In this case, there is a restriction that variations in properties such as viscosity and vapor pressure of the liquid that is fuel are within a certain range. However, according to the operation control method of the present invention, it is possible to use methanol instead of using gasoline as fuel in the gasoline engine.

[0038]

As described above, according to the operation control method of the gas heat pump type air conditioner according to the first aspect of the present invention, the kind of gas can be specified when the gas engine is started. By correcting the operating conditions according to the specified several kinds of gas, it becomes possible to use several kinds of gas as the fuel of the gas engine. Therefore, various gases can be used as fuel for the gas engine by correcting the operating conditions at the time of starting without setting the operating conditions in advance according to the type of gas.

Further, according to the operation control method of the gas heat pump type air conditioner of the second aspect, the operating conditions (fuel valve opening, ignition timing, throttle opening, and starter depending on the specified gas type are used. By correcting the number of revolutions, it becomes possible to use several kinds of gas as fuel for the gas engine. Therefore, various gases can be used as fuel for the gas engine by correcting the operating conditions at the time of starting without setting the operating conditions in advance according to the type of gas.

Further, according to the operation control method of the gas heat pump type air conditioner of the third aspect, the type of gas can be characterized by detecting the lean limit of the gas engine under a predetermined operating condition. Yes, by correcting the operating conditions according to the specified gas type,
A stable output of the gas engine will be obtained. Therefore, even if the gases are of the same type but different in composition and combustion characteristics, the output of the gas engine becomes unstable, the exhaust gas component changes, and knocking occurs. Instead, a stable output can be obtained. Further, even if there are individual differences in gas engines due to manufacturing variations, stable output can be obtained.

According to the operation control method of the gas heat pump type air conditioner of the fourth aspect, the fuel valve opening degree, the ignition timing and the throttle opening degree are set to predetermined values, and the gas engine is operated under the predetermined operation conditions. By detecting the lean limit of, the gas type is specified, and by correcting the fuel valve opening and the ignition timing to predetermined values according to the specified gas type,
A stable output of the gas engine will be obtained. Therefore, even if the gases are of the same type but have slightly different components and combustion characteristics, the output of the gas engine may become unstable, the exhaust gas components may change, or knocking may occur. There is no problem, and stable output can be obtained. Further, even if there are individual differences in gas engines due to manufacturing variations, stable output can be obtained.

[Brief description of drawings]

FIG. 1 is a system diagram showing an overall configuration of a gas heat pump type air conditioner used for carrying out a gas engine operation control method according to the present invention.

FIG. 2 is a block diagram showing an embodiment of a gas engine operation control method according to the present invention.

FIG. 3 is a flow chart showing an operation control method at the time of starting of the gas engine operation control method according to the present invention.

FIG. 4 is a flow chart showing an operation control method during operation of the gas engine operation control method according to the present invention.

FIG. 5 is an explanatory diagram showing an example of a control map used for carrying out the operation control method of the gas engine of the present invention.

FIG. 6 is an explanatory diagram showing components and combustion characteristics according to the type of gas.

FIG. 7 is an explanatory diagram showing components and combustion characteristics according to the type of gas.

[Explanation of symbols]

11 compressor GE gas engine Gf Fuel valve opening Igt ignition timing θth throttle opening Vst Starter speed

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) F02D 41/02 301 F02D 41/02 301K 41/06 310 41/06 310 325 325 45/00 364 45/00 364K F02N 11/08 F02N 11/08 G F02P 5/15 F02P 5/15 E (72) Inventor Mitsuji Yoshimura 3-1, 1 Asahi-cho, Nishibiwajima-cho, Nishikasugai-gun, Aichi Mitsubishi Heavy Industries, Ltd. Cooling Business Division (72) Inventor Akira Nakajima 3-1, Asahi-cho, Nishibiwajima-cho, Nishikasugai-gun, Aichi Prefecture Mitsubishi Heavy Industries, Ltd., Cooling & Heat Business Division (72) Inventor Takuya Okada 3-chome, Asahi-cho, Nishibiwajima-cho, Nishikasugai-gun, Aichi Prefecture Mitsubishi Heavy Industries, Ltd. F-terms in business headquarters (reference) 3G022 CA01 GA05 GA07 3G084 BA05 BA11 BA17 CA01 DA11 FA21 FA34 3G092 AB0 7 AC07 DE11S EA11 EC09 GA01 HA06X HB05Z HC01Z HC09X HE02Z HF05X 3G093 AA01 CA01 DA00 DA01 FA07 FA10 3G301 HA22 JA04 KA01 LA01 MA11 ND02 PC01Z PE02Z PE09A

Claims (4)

[Claims] 1. A refrigeration cycle is formed by circulating a refrigerant through the cooperation of a gas engine that uses gas as a fuel and a compressor that uses the gas engine as a drive source, and waste heat discharged from the gas engine is formed. While collecting in engine cooling water,
A method for controlling the operation of a gas engine of a gas heat pump type air conditioner configured to heat a refrigerant by the engine cooling water to increase a heating capacity, wherein the gas engine is started under a predetermined operating condition when the gas engine is started. Let me
The feature is that it determines whether or not the gas engine starts, identifies the gas type based on the result, and continuously operates the gas engine under the initial operating condition or the corrected operating condition according to the identified gas type. And operation control method of gas engine. 2. The gas engine operation control method according to claim 1, wherein the operating condition is at least one of a group selected from a fuel valve opening, an ignition timing, a throttle opening, and a starter rotation speed. The above is the operation control method of the gas engine characterized by the above. 3. A refrigeration cycle is formed by circulating a refrigerant by cooperation between a gas engine that uses gas as a fuel and a compressor that uses the gas engine as a drive source, and waste heat discharged from the gas engine is formed. While collecting in engine cooling water,
A method for controlling operation of a gas engine of a gas heat pump type air conditioner configured to heat a refrigerant by the engine cooling water to increase heating capacity, wherein the gas engine is operated under predetermined operating conditions during steady operation of the gas engine. A gas characterized by detecting the lean limit, specifying the type of gas based on the result, correcting the operating conditions according to the specified type of gas, and operating the gas engine continuously under the corrected operating conditions. Engine operation control method. 4. The method for controlling operation of a gas engine according to claim 3, wherein the predetermined operating condition is a fuel valve opening degree,
A method for controlling operation of a gas engine, comprising at least one of a group selected from ignition timing and throttle opening, and the operating condition to be corrected is one or both of a fuel valve opening and ignition timing.