JPH0533696A - Control method of engine driven heat pump - Google Patents

Abstract

PURPOSE:To prevent any possible drop in startability regardless of a secular change in an engine by setting the opening of a throttle valve at the time of engine starting on the basis of the opening at the last starting, in starting control over the engine applicable to a heat pump air conditioner or the like. CONSTITUTION:An engine-driven heat pump system is provided with an outdoor machine 1A and an indoor machine 4A, while a heating circuit A and a cooling circuit B are installed each in these machines. In addition, a fuel feed pipe 12 is connected to a gas engine 1 of the outdoor machine 1A via a throttle valve 11, while a starter 13, a cooling water temperature sensor 14 and an engine speed sensor 15 are all connected thereto as well. In succession, the throttle valve 11 is controlled for opening or closing by an outdoor controller 9 via a stepping motor 16. In this case, opening of the throttle valve 11 at the time of the gas engine 1 should be set on the basis of that at the last starting. Moreover, during cranking, the above opening is expansibly operated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an operation control technique of a device for driving a compressor by an engine using natural gas, petroleum or the like as a fuel to perform heat pump cooling / heating operation.

[0002]

2. Description of the Related Art Conventionally, as an engine driven heat pump, an engine, a compressor, a four-way valve, an indoor heat exchanger, a receiver tank, an outdoor electric valve, an outdoor heat exchanger, an accumulator, etc. are sequentially connected to perform a heating operation only in winter. Instead, it is often manufactured and supplied in a configuration that can be used for cooling operation in summer.

Such engine driven heat pump cooling /
As a heating device, for example, a technique proposed in Japanese Examined Patent Publication No. 3-32712 is known, and a method for controlling an engine is disclosed in Japanese Examined Patent Publication Nos. 63-32973 and 63-40925. Specific proposals have been made.

However, in any of the above-mentioned prior arts, the throttle valve at engine startup is as shown in FIG.
During cranking, it does not change and is fixed and waiting for a complete explosion, so 1) the engine may not complete (depending on the throttle valve opening) (throttle valve is too closed) 2) engine complete explosion At the same time, the engine speed suddenly rises and hunts (throttle valve opens too much). 3) When the engine malfunctions due to aging, etc., there are various problems that the throttle valve is fixed and the explosion does not complete. The positioning of the throttle valve when starting the engine was complicated and was an important problem.

Further, when the cooling / heating operation is started, or when the load changes abruptly due to a large change in the set temperature, the opening of the throttle valve is adjusted so as to promptly respond to this rapid load change. Hunting occurs when the amount of fuel supplied to the engine is changed drastically to cause a large change, and when the throttle valve opening is gently changed so as not to cause hunting, the response time when the amount of load fluctuation is large becomes longer. There was a problem.

[0006] The rotational speed of the engine is for a configuration to be controlled according to the installation number and load of the indoor unit, attempts to change the rotational speed when the like commissioning capacity measurement and exhaust gas (e.g., NO _X) Measurement However, there is a problem that it is not easy to change the load because the setting of the load becomes large.

[0007]

[SUMMARY OF THE INVENTION That is, in the conventional engine driven heat pump, for starting of the engine is inferior, hardly with the variation of the load, it is not easy change of rotational speed, commissioning and exhaust gas (e.g., NO _X ) There are various problems that it is difficult to perform the measurement work efficiently, and it has been a problem to solve this problem.

[0008]

As a concrete means for solving the above-mentioned problems of the prior art, the present invention relates to a throttle valve opening at the time of engine startup in the startup control of an engine used for a heat pump cooling / heating system or the like. In the control method of the engine-driven heat pump, which is calculated and set based on the opening degree when last started, and the start control of the engine used for the heat pump cooling / heating device,
A method for controlling an engine-driven heat pump, characterized in that the throttle valve opening at engine startup is calculated and set based on the opening at the previous startup, and the opening is enlarged during cranking. A function having variables of initial setting throttle valve opening Φ _n , throttle valve opening Φ _n-1 at the start of complete explosion when started last time, and cooling water temperature t ₁ at complete explosion when started last time F (t ₁ ) and a function F (t ₂ ) having the cooling water temperature t ₂ at the time of startup as a variable,
From the constant A, Φ _n = Φ _n-1 −F (t ₁ ) + F (t ₂ ) −A
Based on the difference between the engine speed set according to the load and the actual engine speed detected by the sensor, in the engine drive heat pump control method set as When operating the throttle valve by operating the throttle valve at a speed corresponding to the operation amount of the throttle valve, a method for controlling an engine-driven heat pump characterized by operating the throttle valve, and an engine speed control for a heat pump cooling / heating device, etc. By providing a forced rotation switch for rotating the engine at a predetermined engine speed, and by turning on the switch to rotate the engine at a set speed, by providing a method for controlling an engine-driven heat pump, It solves the problems of the related art.

[0009]

[Operation] In the control method in which the throttle valve opening at the time of engine startup is calculated and set based on the opening at the time of previous startup, the throttle valve operation based on the previous startup is used even if the engine changes over time. Since it is performed, it is possible to prevent the deterioration of the startability.In addition, in the control method in which the opening degree of the throttle valve is enlarged during cranking, ignition is performed in a lean fuel state to quickly increase the fuel supply amount. By increasing the value to 1, the incomplete explosion of the engine is eliminated and the startability is remarkably improved. Further, since the fuel supply amount at the time of starting is suppressed, the occurrence of hunting is also prevented. Also, in the control method in which the opening of the throttle valve is operated based on the difference between the engine speed set according to the load and the actual engine speed, when starting operation or when the set temperature is changed significantly, When the amount of change in load is large and the amount of operation of the throttle valve is large, the throttle valve is driven faster, and conversely, when the amount of change in load is small and the throttle valve can be operated slightly, the throttle valve is gently driven. Prompt response to changes is possible and hunting does not occur.
Further, in the control method of rotating the engine at a predetermined rotation speed by the forced rotation switch, the engine is rotated at a predetermined rotation speed by turning on the switch, so that a trial run or NO _X performed at a specific rotation speed is performed. Efficiently measure exhaust gas and adjust ignition timing.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an example of a system diagram of an engine driven heat pump adopting the engine starting control according to the present invention. In the figure, 1A is an outdoor unit, 1 is a gas engine that uses, for example, city gas as fuel (hereinafter, simply referred to as engine), 2 is a compressor, 3 is a four-way valve, 4A is an indoor unit, 4 is an indoor heat exchanger, 5 Is a receiver tank, 6 is an outdoor electric valve, 7 is an outdoor heat exchanger, and 8 is an accumulator. These devices are not different from those conventionally known, and they are sequentially connected to each other to form a heating circuit A and a solid line. And a cooling circuit B shown in FIG.
A fuel supply pipe 12 is connected via a fuel cell, a starter 13 for starting the engine 1, a sensor 14 for measuring the temperature of cooling water, and a sensor 15 for detecting the rotational speed of the engine 1 are provided. The starter 13 can be operated and the detection data of the sensors 14 and 15 can be incorporated to make the throttle valve 11
An outdoor controller 9 capable of adjusting the opening degree of is connected. A remote control device (hereinafter, referred to as a remote controller) 9b is connected to the outdoor controller 9 via an indoor controller 9a by serial communication wiring, and the operation of the engine 1 is controlled indoors.

The throttle valve 11 for adjusting the amount of fuel supplied to the engine 1 can be driven and controlled by appropriate means, but here, the throttle valve 11 is used.
Will be described based on an embodiment using the stepping motor 16 in which the minimum opening is 0 step and the maximum opening is 400 steps. The throttle valve 11 when starting the engine 1 is driven and controlled as shown in FIG. 2, for example.

That is, the throttle valve 11 is set to a certain predetermined opening degree, starts cranking, and is held at this opening degree for a predetermined time (for example, 1 second), and then the opening degree is controlled to a predetermined control speed (for example, 125 ms). / Step) for a predetermined time (for example, 5 seconds) to wait for the engine 1 to completely explode, and then hold the opening for a predetermined time (for example, 1 second) to start normal operation control.

The opening degree of the throttle valve 11 at the start of cranking, that is, the initial setting opening degree Φ _n is the opening degree Φ _n-1 of the throttle valve at the time of starting the complete explosion when the engine is started last time. , A function F (t ₁ ) having a variable of the cooling water temperature t ₁ detected by the sensor 14 at the start of complete explosion at the previous engine startup, and a function F (having a variable of the cooling water temperature t ₂ at the current startup. t ₂ ) and a constant A, which is determined by the arithmetic unit incorporated in the outdoor controller 9. When the operation start switch (not shown) of the remote controller 9b is turned on, the starter 13 that starts the engine 1 is started. Before being driven, the stepping motor 16 is driven by a predetermined amount and automatically set according to an instruction from the outdoor controller 9.

More specifically, the initial setting opening Φ _n of the throttle valve 11 is calculated based on the formula Φ _n = Φ _n-1 −F (t ₁ ) + F (t ₂ ) −A, for example. It is set, and the function F (t ₁ ), the function F (t ₂ ), and the constant A are appropriately determined according to the type of the engine 1 (gas engine, gasoline engine, etc.), model, capacity, etc.

The function F (t) is, for example, the function illustrated in FIG. 3, that is, F (t) = 80 (t <−20) F (t) = − t + 60 (−20 ≦ t ≦ 60) F (t t) = 0 (60 <t), where t is t ₁ or t ₂ in the above function.
Is. For example, in the device control with the constant A set to 20, if Φ _n-1 is 120, the function F when the temperature t ₁ of the previous cooling water detected by the sensor 14 is 10 ° C.
(t ₁ ) is 50, and the function F (t ₂ ) when the cooling water temperature t ₂ this time is 60 ° C. is 0, and the initial setting opening Φ _n of the throttle valve 11 at this time is Φ _n = Φ _{It is given as n-1} −F (t ₁ ) + F (t ₂ ) −A = 120−50 + 0−20 = 50 (step). Therefore, the stepping motor 16 is driven by an instruction from the outdoor controller 9, and the initial setting opening Φ _n of the throttle valve 11 is automatically set to the position of 50 steps.

After the opening of the throttle valve 11 is set to 50 steps in this way, the outdoor controller 9
The starter 13 is driven to start cranking according to the instruction. Then, after 1 second has elapsed, the stepping motor 16 is driven for 5 seconds at a control speed of 125 ms / step,
The opening of the throttle valve 11 is increased by 40 steps, and the opening of 90 steps (50 + 40) is held for 1 second. In this cranking, when the rotation speed of the engine 1 detected by the sensor 15 does not reach 700 rpm or more, the operation start operation by the remote controller 9b is repeated again. When the engine speed is 700 rpm or more, it is determined that the complete explosion has occurred, and the opening Φ of the throttle valve 11 when the complete explosion is started is stored in the memory of the outdoor controller 9, and then the engine 1 is turned on. Information for determining the initial opening Φ _n at startup as described above (Φ
_n-1 ). Then, the operation control of the engine 1 thereafter is controlled by a conventionally known method or the like.

The function F (t) for determining the initial set opening Φ _n of the throttle valve 11 may be a quadratic function or the like, and each parameter for determining the initial set opening Φ _n is It is also possible to appropriately set an upper limit value and a lower limit value (for example, Φ _n-1 -F (t ₁ ) -A has a minimum value of 30 steps,
Maximum 50 steps).

As described above, according to the engine start control method of the present invention, the initial set opening Φ _n of the throttle valve 11 is set.
When the fuel becomes lean, the engine 1 is set to an opening that is on the verge of complete explosion to start cranking, and the opening is rapidly increased during cranking to increase the fuel concentration to ensure complete completion. Since this is an explosive method, the gradient of the step movement for increasing the opening during cranking is not limited to the above-mentioned embodiment, and is appropriately determined depending on the engine type (gas, gasoline, etc.), model, capacity, etc. Just go.

FIG. 4 is an example of a system diagram of an engine-driven heat pump that employs engine speed control according to the present invention. As in FIG. 1, the heating circuit A and the cooling circuit B sequentially include the engine 1, the compressor 2, the four-way valve 3, the indoor heat exchanger 4, the receiver tank 5, the outdoor electric valve 6, the outdoor heat exchanger 7, and the accumulator 8. The outdoor controller 9 is formed by being connected to each other, and has a comparison calculation unit 91, a step speed calculation unit 92, and a stepping motor control unit 93 in addition to a normal control function such as operation start / stop. Part 91
A sensor 15 that detects the number of revolutions of the engine 1 is connected to, and data is input to the comparison calculation unit 91. Further, the sensor 41 attached to the indoor heat exchanger 4 for measuring the indoor temperature is connected to the indoor controller 9a, and data is input from the indoor controller 9a to the outdoor controller 9 by serial communication. Then, the stepping motor control unit 93 is connected so that a drive pulse can be emitted toward the stepping motor 16 in order to adjust the opening degree of the throttle valve 11 based on the calculation result of the step speed calculation unit 92. .

In controlling the apparatus having the above structure, the temperature difference ΔT between the room temperature set in the indoor heat exchanger 4 by the remote controller 9b and the actual room temperature detected by the sensor 41 is first calculated in the comparison calculation section 91, and then Then, the rotational speed difference ΔN between the predetermined rotational speed of the engine 1 corresponding to the temperature difference ΔT and the actual rotational speed of the engine 1 detected by the sensor 15 is calculated. The predetermined number of revolutions of the engine 1 corresponding to the temperature difference ΔT is preset and stored in the memory (not shown) of the controller 9.

Next, in the step speed calculation unit 92,
Stepping motor 1 for operating the throttle valve 11
The control amount X and the control speed Y of 6 are calculated as X = aΔN + b Y = cX + d (a, b, c and d are constants).

For example, a = 0.05, b = 0, c = 0.
In the control of 1 and d = 30, the set room temperature is 27 ° C.
When the room temperature detected by the sensor 41 is 32 ° C., the temperature difference ΔT is calculated as ΔT = 27−32 = −5 (° C.), and the engine 1 corresponding to this load (temperature difference) is calculated.
The predetermined rotation speed of the engine 1 is 1800 rpm, and the actual rotation speed of the engine 1 detected by the sensor 15 is 1000 rp, for example.
If it is m, the comparison calculation unit 91 calculates the rotation speed difference ΔN as ΔN = 1800−1000 = 800 (rpm), and the step speed calculation unit 92 calculates X = 0.05 × 800 = 40 (step) Y = 0.1X + 30 = 34 (step / sec) is calculated.

Based on the result of this calculation, the stepping motor control section 93 outputs a drive pulse of a control amount of 40 steps and a control speed of 34 steps / sec to the stepping motor 16 so that the stepping motor 16 opens the throttle valve 11. The fuel supply to the engine 1 sharply increases, and the rotation speed of the engine 1 visibly increases because the engine speed is rapidly and greatly expanded. Therefore, it is possible to quickly respond to a sudden change such as the cooling load.

The driving / control of the throttle valve 11 by the stepping motor 16 is performed at an appropriate interval, for example, 1
Since it is performed at intervals of 0 to 60 seconds, the temperature difference ΔT = −5 ° C. is confirmed at a certain moment, and even if the opening degree of the throttle valve 11 is enlarged and rapidly expanded as described above, When it is confirmed that the temperature difference ΔT is, for example, −1 ° C. during a certain control, the set rotational speed of the engine 1 corresponding to this temperature difference ΔT = −1 ° C. is, for example, 1000 rpm, and the sensor 1
If the actual rotation speed detected by No. 5 is 900 rpm, the comparison calculation unit 91 calculates the rotation speed difference ΔN as ΔN = 1000−900 = 100 (rpm), and the step speed calculation unit 92 calculates the control amount X.
And the control speed Y are calculated as X = 0.05 × 100 = 5 (step) Y = 0.1X + 30 = 30.5 (step / sec).

Therefore, the stepping motor controller 93
Drive pulse of 5 steps, control speed; 30.5 steps / sec is emitted toward the stepping motor 16, and the stepping motor 16 gradually and slightly expands the opening of the throttle valve 11. Since the amount of change in the fuel supplied to No. 1 is gentle and small, the rotation speed of the engine 1 gradually increases.

The control under the condition that the temperature difference ΔT = -1 ° C. is such that when the room temperature is set to 27 ° C. and there is a person coming in and going out during the cooling operation, the room temperature is only 28 ° C. It is also a control when it rises to.

Therefore, when there is a large load change and it is necessary to greatly change the opening of the throttle valve 11, the stepping motor 16 drives and controls the throttle valve 11 at a large control speed to slightly change the opening of the throttle valve 11. When it is sufficient, the stepping motor 16 gently drives the throttle valve 11. In this way, the fuel supply to the engine 1 is controlled, so that it is possible to quickly respond to load changes and prevent hunting.

Even when the rotation speed of the engine 1 is decreased due to a decrease in the cooling load, the drive and control are performed in the same manner as when the rotation speed is increased, so that it is possible to respond promptly and without causing hunting. be able to. Further, the calculation of the control amount and the control speed is not limited to the linear equation. It is also possible to set an upper limit and a lower limit to the control speed.

FIG. 5 is an explanatory view showing the essential parts of an engine-driven heat pump that employs the forced engine speed control according to the present invention. The outdoor controller 9 has not only a normal control function but also a forced rotation speed setting switch 94, and a rotation speed increase switch 95 for increasing the rotation speed of the engine 1 when the switch 94 is continuously pressed when the switch is turned on. A rotation speed reduction switch 96 for decreasing the rotation speed if continued, and display parts 97 and 9 made of, for example, an LED for displaying the engine rotation speed set in this manner,
The rotation speed of the engine 1 is controlled by means such as PID control so that the rotation speed read from the ignition 17 of the engine 1 becomes the set rotation speed.

In the control of the apparatus having the above-mentioned structure, if the switch 94 is turned on and the rotation speed increase switch 95 is continuously pressed, the rotation speed of the engine 1 is increased, and if the rotation speed reduction switch 96 is continuously pressed, the rotation speed is reduced. since the ability measured during commissioning, the measurement of the exhaust gas (e.g., NO _X), when such adjusting ignition timing of the engine, it is possible to easily obtain a desired engine speed.

The engine start control method shown in FIGS. 1 to 3, the engine speed control method shown in FIG. 4, and the engine speed control method shown in FIG.
The forced rotation speed control methods of the engine shown in (4) can be used in combination with each other.

[0032]

As described above, in the control method for calculating and setting the throttle valve opening when the engine is started based on the opening when the engine was last started, the throttle valve is opened more than when it is new because the engine is aged. Even if you do not complete the explosion unless you open the valve, the throttle valve operation is performed based on the previous opening when the explosion is complete, so it is possible to prevent the startability from deteriorating. In the control method in which the opening degree of the valve is enlarged, ignition is performed in a lean fuel state to rapidly increase the fuel supply amount, so that an incomplete explosion of the engine is eliminated and the startability is remarkably improved. Further, since the fuel supply amount at the time of starting is suppressed, hunting does not occur. In addition, in the control method in which the opening of the throttle valve is operated in proportion to the difference between the engine speed set according to the load and the actual engine speed, when the operation is started or the set temperature is changed significantly. For example, when the amount of change in load is large and the amount of operation of the throttle valve is large, the throttle valve is driven faster, and conversely, when the amount of change in load is small and the throttle valve can be operated slightly, it is driven gently. Prompt response to any fluctuations and no hunting occur.
Further, in the control method of rotating the engine at a predetermined rotation speed by the forced rotation switch, the engine is rotated at a predetermined rotation speed by turning on the switch, so that a trial run or NO _X performed at a specific rotation speed is performed. Exhaust gas measurement and ignition timing adjustment can be performed efficiently.

[Brief description of drawings]

FIG. 1 is a system diagram of an engine-driven heat pump to which engine starting control according to the present invention is applied.

FIG. 2 is an explanatory diagram of a function F (t) used to calculate an initial setting opening Φ _n of a throttle valve.

FIG. 3 is an explanatory diagram showing an example of control of a throttle valve when the engine is started.

FIG. 4 is a system diagram of an engine-driven heat pump to which engine speed control according to the present invention is applied.

FIG. 5 is an explanatory diagram showing a main part of an engine-driven heat pump to which the forced engine speed control according to the present invention is applied.

FIG. 6 is an explanatory diagram at the time of starting the engine in the conventional example.

[Explanation of symbols]

1 gas engine 11 Throttle valve 12 Fuel supply pipe 13 Starter 14 sensors 15 sensors 16 stepping motor 17 ignition 2 compressor 3 four-way valve 4 Indoor heat exchanger 5 receiver tank 6 outdoor electric valve 7 Outdoor heat exchanger 8 Accumulator 9 Outdoor controller 9a Indoor controller 9b Remote control device 1A outdoor unit 4A indoor unit A heating circuit B cooling circuit

Claims (5)

[Claims] 1. In starting control of an engine used for a heat pump cooling / heating device or the like, the throttle valve opening at the time of starting the engine is calculated on the basis of the opening at the time of previous starting.
A method for controlling an engine-driven heat pump, comprising setting. 2. In the start control of an engine used for a heat pump cooling / heating device or the like, the throttle valve opening at the time of starting the engine is calculated based on the opening at the time of the previous start.
A method for controlling an engine-driven heat pump, which comprises setting and enlarging the opening during cranking. 3. The initially set throttle valve opening Φ _n at engine startup, the throttle valve opening Φ _n-1 at the start of complete explosion at the previous startup, and the cooling water at complete explosion at the previous startup. a function F (t ₁₎ for the temperature t ₁ and variable, as a function to the cooling water temperature t ₂ of the present activation time as a variable F (t _2), and a constant _{a, Φ n = Φ n-} 1 -F The method for controlling an engine-driven heat pump according to claim _{1, wherein} (t ₁ ) + F (t ₂ ) -A is set. 4. In the engine speed control of an engine used for a heat pump cooling / heating device or the like, a throttle valve is operated based on a difference between an engine speed set corresponding to a load and an actual engine speed detected by a sensor. A method for controlling an engine-driven heat pump, comprising operating a throttle valve at a speed according to an operation amount of the throttle valve. 5. In the engine speed control of an engine used for a heat pump cooling / heating device or the like, a forced rotation switch for rotating the engine at a predetermined engine speed is provided,
A method for controlling an engine-driven heat pump, characterized in that the engine is rotated at a set speed by turning on the switch.