JP3913440B2 - Air conditioner - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an air conditioner using a compressor driven by a gas engine, and more particularly to a technique for controlling a gas supply solenoid valve.
[0002]
[Prior art]
In recent years, an engine-driven air conditioner using a gas engine as a drive source of a compressor in an outdoor unit has been widely adopted from the viewpoint of energy saving. Such an air conditioner uses natural gas (LNG) or propane gas (LPG) as fuel, and two gas solenoid valves and one gas supply pipe for guiding gas as fuel to the gas engine. A gas proportional valve is provided in series. First, the gas solenoid valve simply opens and closes the valve to supply / stop the fuel gas, and the gas proportional valve changes the current by changing the opening of the valve. The amount of gas supplied to the combustion chamber of the gas engine is adjusted.
[0003]
The details are as follows. FIG. 6 is a circuit configuration diagram of a gas solenoid valve driving device that performs opening / closing control of a gas supply solenoid valve used in a conventional gas engine driven air conditioner.
[0004]
This gas solenoid valve drive device is provided with drive circuits (D11, D12) and relays (R11, R12) for controlling two gas solenoid valves (G11, G12), respectively, and the operation signal to these is one microcomputer. (MPU). As the operation of the gas solenoid valves (G11, G12), when the operation is started, a command by a pulse signal is generated from the microcomputer, the gas solenoid valve G11 and the gas solenoid valve G12 are opened, and the fuel gas is passed through the gas supply pipe. Is supplied to the gas proportional valve G13 . The fuel gas that has passed through the respective gas solenoid valves (G11, G12) is supplied to the combustion chamber of the gas engine by adjusting the gas supply amount by the gas proportional valve G13, and operates to drive the gas engine.
[0005]
[Problems to be solved by the invention]
However, when an abnormality occurs in the microcomputer (for example, the microcomputer runs away and the program does not operate normally), the gas solenoid valve may be forcibly opened. Therefore, it has been desired to solve this problem.
[0006]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, the invention according to claim 1 is an air that constitutes a refrigeration cycle by connecting a compressor driven by a gas engine, an outdoor heat exchanger, and an indoor heat exchanger with refrigerant piping. In the conditioner, a gas supply pipe that guides gas as fuel to the gas engine is provided with a plurality of gas solenoid valves in series, and these gas solenoid valves include an MPU that controls power supply of the gas solenoid valve, It is controlled by a plurality of MPUs that control the opening / closing drive of the gas solenoid valve .
[0007]
According to the first aspect of the present invention, since the gas solenoid valve provided in the gas supply pipe of the gas engine is controlled by a plurality of MPUs, the gas solenoid valve is not opened even if any MPU malfunctions. Since it is not performed, gas leakage can be prevented and reliability can be improved.
[0008]
According to the second aspect of the present invention, it is possible to expect the same effect of preventing abnormal gas solenoid valve operation without providing a feedback control circuit by combining the individual drive when the gas solenoid valve is OFF and the multi-MPU.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0010]
FIG. 1 is a schematic configuration diagram of a gas heat pump type air conditioner using a gas engine. The air conditioner according to the present embodiment is a so-called multi-type package air conditioner, and includes a plurality of indoor units 1 and one outdoor unit 3. On the indoor unit 1 side, an indoor heat exchanger 7 to which a flow divider 5 is attached, an electric fan 9, an electric expansion valve 11, and the like are installed. Reference numeral 51 denotes an indoor side control unit (hereinafter referred to as ECU) that drives the electric fan 9 and the electric expansion valve 11. The indoor ECU 51 includes an MPU, an input / output interface, ROM, RAM, a timer counter, and the like. Has been.
[0011]
On the other hand, on the outdoor unit 3 side, an outdoor heat exchanger 19, an electric fan 21, an accumulator 23, an outdoor ECU 61, and the like provided with a compressor 13, a four-way valve 15, and a flow divider 17 are installed.
[0012]
Inside the outdoor unit 3, an outdoor ECU 61 that centrally controls the four-way valve 15, the electric fan 21, the electromagnetic shut-off valve 49, and the equipment related to the gas engine 25 including the step motor 29 is installed. . The outdoor ECU 61 includes an MPU, an input / output interface, a ROM, a RAM, a timer counter, and the like, and is provided in a gas supply pipe (not shown) that guides a gas (LNG or LPG) as fuel to the gas engine. It controls the opening and closing of two gas solenoid valves.
[0013]
The ECU 61 is also connected to a rotation sensor 65 that detects the number of revolutions of the engine 25 and a fuel adjustment valve 10 that controls the amount of fuel supplied to the engine 25, and is based on data measured by the pressure sensor and temperature sensor. Thus, the operation of the engine 25 is controlled. The fuel adjustment valve 10 includes two gas solenoid valves (G1, G2) disposed in a gas pipe 70 connected to the gas engine 25.
[0014]
2 and 3 are block configuration diagrams of a circuit for controlling the gas solenoid valve according to the embodiment of the present invention, and operations of the two control circuits will be described based on the block diagrams.
[0015]
This control circuit is composed of two MPUs (M1, M2), three drive circuits (D1-D3), and three relays (R1-R3). The opening and closing of (G1, G2) and the energization of the crankcase heater M3 of the compressor 13 are controlled. As the division of roles of the two MPUs, one MPU1 (M1) drives the relay R1 through the drive circuit 1 (D1) to energize the crankcase heater M3, or supplies power to the relay R2 and the relay R3. The other MPU2 (M2) drives the relay R2 via the drive circuit D2 to open and close the gas electromagnetic valve G1, and further drives the relay R3 via the drive circuit D3 to open and close the gas electromagnetic valve G2. . For this reason, if an abnormality occurs in one MPU1 (M1) and the switch of the relay R1 stops switching to the contact a, power is not supplied to the relay R2 and the relay R3, and the two gas solenoid valves (G1, G2) There is no opening. In addition, even if an abnormality occurs in the other MPU 2 (M2), the drive instruction to the relay R2 and the relay R3 is not performed, so that the two gas solenoid valves (G1, G2) are not opened.
[0016]
Next, the flow which shows the flow of the gas solenoid valve control by the control circuit mentioned above is shown in FIG. First, one MPU 1 (M1) determines whether or not an operation start signal is input, and the process is repeated until this signal input is generated (step S1). In step 2, a start instruction for the gas engine is issued, the energization output to the crankcase heater is turned off, and power supply to the relays R2 and R3 that drive the gas solenoid valve is started.
[0017]
The other MPU2 (M2) receives the gas engine start signal from one MPU1 (M1) and issues an instruction to open the two gas solenoid valves (G1, G2) (step S3). Furthermore, the start and complete explosion of the engine are confirmed, and a complete explosion notification signal of the gas engine is transmitted to one MPU 1.
[0018]
Subsequently, one MPU 1 (M1) receives the gas engine complete explosion notification signal and starts operation control of the gas engine (step S5). In step S6, it is determined whether or not an operation stop signal is input, and the process is repeated until this signal input is generated (step S1). Then, a gas engine operation stop signal is transmitted again to the other MPU 2 (M2) (step S7).
[0019]
The other MPU2 (M2) again turns off the two gas solenoid valves (G1, G2) alternately after confirming the gas engine stop instruction from one MPU1 (M1). The order of turning off the two gas solenoid valves is changed every time the gas engine is stopped (step S8). At this time, it is determined whether the gas engine has stopped when the gas solenoid valve is turned off for the first time. If the gas engine does not stop, it is determined that the gas solenoid valve is malfunctioning. If the gas engine stops, the gas solenoid valve is determined to be normal. Then, a gas engine stop signal is transmitted to one MPU 1 (M1) (steps S9 to S11).
[0020]
Finally, one MPU1 (M1) that has received the gas engine stop signal stops supplying power to the relays R2 and R3 that drive the gas solenoid valve, and starts energizing the crankcase heater (step S12).
[0021]
FIG. 5 is a chart showing the time series of output signals transmitted to each device based on the flowchart shown in FIG. The horizontal axis of the chart of FIG. 5 shows a time series, indicating that time has elapsed in the right direction as t1 to t10, (1) is an operation / stop signal, and (2) is a gas engine. Start / stop instruction signal (MPU1 → MPU2), (3) Clan case heater energization signal, (4) is one gas solenoid valve opening instruction signal, (5) is the other gas solenoid valve opening instruction signal, and (6) is gas An engine start / stop completion signal is shown.
[0022]
The flow of these signals is as follows. At time t1, (1) the operation / stop signal is ON, and at time t2, (2) is the gas engine start / stop instruction signal (MPU1 → MPU2) is ON (3). Clan case heater energization signal is OFF, at time t3, (4) is one gas solenoid valve opening instruction signal, and (5) is the other gas solenoid valve opening instruction signal, and at time t4, (6) is gas engine start / The stop completion signal turns ON. At time t5 (1), the operation / stop signal is OFF, at time t6 (2), the gas engine start / stop instruction signal (MPU1 → MPU2) is OFF, and at time t7, (4) is one gas solenoid valve opening instruction. When the signal is OFF, at time t8 (5), the other gas solenoid valve opening instruction signal is OFF, at time t9, (6), the gas engine start / stop completion signal is OFF, and at time t10, (3) Clan case heater energization signal Turns off.
[0023]
As mentioned above, although this invention was demonstrated based on the said embodiment, this invention is not limited to this.
[0024]
【The invention's effect】
As described above, according to the first aspect of the present invention, the gas solenoid valve provided in the gas supply pipe of the gas engine is controlled by a plurality of MPUs. Since the solenoid valve is not opened, gas leakage can be prevented and reliability can be improved.
[0025]
Further, according to the invention of claim 2, the combination of the individual drive when the gas solenoid valve is OFF and the multi-MPU can be expected to have an effect of preventing an abnormal gas solenoid valve operation without providing a feedback control circuit. Thus, the circuit board can be simplified and manufactured at low cost.
[Brief description of the drawings]
FIG. 1 is a refrigerant circuit diagram showing the structure of a gas engine driven air conditioner according to the present invention.
FIG. 2 is a block diagram 1 showing one embodiment of a control circuit according to the present invention.
FIG. 3 is a block diagram 2 showing an embodiment of a control circuit according to the present invention.
FIG. 4 is a flowchart showing a flow of operation of the control circuit according to the present invention.
FIG. 5 is a chart showing timings at which control signals of the control circuit according to the present invention are generated.
FIG. 6 is a block diagram showing a control configuration of a gas solenoid valve of a conventional gas engine driven air conditioner.
[Explanation of symbols]
7 Indoor Heat Exchanger 13 Compressor 19 Outdoor Heat Exchanger 25 Gas Engine 33-45 Refrigerant Pipe 70 Gas Supply Pipe M1, M2 MPU
G1, G2 Gas solenoid valve

Claims (2)

A gas supply pipe that guides a gas as fuel to the gas engine in an air conditioner that configures a refrigeration cycle by connecting a compressor driven by a gas engine, an outdoor heat exchanger, and an indoor heat exchanger with refrigerant piping Is equipped with a plurality of gas solenoid valves in series, and these gas solenoid valves are controlled by a plurality of MPUs, an MPU for controlling the power supply of the gas solenoid valve and an MPU for controlling the opening / closing drive of the gas solenoid valve. An air conditioner characterized by being made.   The air conditioner according to claim 1, wherein the circuit for controlling the gas solenoid valve of the air conditioner is configured by an output circuit that does not require feedback by detecting an abnormal input by a plurality of MPUs.

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