JPH0221502B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a heat pump used as an air conditioner, a water heater, etc.
The present invention relates to an engine-driven heat pump configured to circulate flow through an expansion valve, an evaporator, and the compressor.

The engine, which is the driving source for this type of heat pump, must be used under conditions of high ambient temperature, such as in locations with poor air flow, such as mechanical rooms, or in locations where other heating sources are present near the engine. If the engine is used in such a high-temperature atmosphere, the same phenomenon as when the engine is operated under overload may occur, resulting in poor combustion and increased exhaust temperature, which may damage the piston, piston ring, cylinder, exhaust valve, and cylinder head. The heat load increases, which tends to shorten the maintenance period, increase maintenance work time, shorten the service life, etc.

In addition, as a means to improve these shortcomings in terms of maintenance and durability, conventionally, a dedicated cooling device has been separately installed to cool the combustion air taken into the engine by heat exchange with cooling water. It is known that the heat pump is equipped with a heat pump, but this method not only increases the size of the entire heat pump, but also has the disadvantage that running costs tend to be high.

Therefore, as shown in Japanese Utility Model Application Publication No. 58-32131 (hereinafter referred to as the reference), a refrigerant/air heat exchanger is interposed in the intake air path of the engine, and the refrigerant of the air conditioning system is connected to the heat exchanger. A known solution is to reduce the intake air temperature of the engine by guiding a portion of the engine.

According to the technology, this reference is configured to cool the intake air temperature based on the detection result of a sensor that detects the intake air temperature when the intake air temperature of the engine exceeds a set value. It has not been possible to deal with cases where the engine load becomes excessive and the engine tends to overheat when the air temperature is below the set value (for example, during continuous maximum heating operation in winter).

In view of the above-mentioned circumstances, the present invention provides
Furthermore, it is possible to advantageously suppress the aforementioned problems caused by poor combustion and increase in exhaust temperature caused by engine operation under an overload in an atmosphere at a suitable temperature, in terms of structure and running cost.

The engine-driven heat pump according to the present invention includes:
By focusing on the fact that the exhaust temperature rises both when the intake air temperature of the engine becomes high and when the intake air temperature is at an appropriate temperature and the engine is overloaded, the exhaust gas temperature increases. A heat exchange unit is provided that can cool the combustion air by heat exchange with the refrigerant after passing through the condenser, and the heat exchange unit detects that the engine exhaust temperature has risen above a set value. The system is characterized in that it is configured to automatically and reversibly switch to the cooling action state based on the detection result of the detection device, so even if the engine is operated under high-temperature atmospheric conditions or suitable temperature atmospheric conditions. In either case, the combustion air is cooled by using the latent heat of vaporization of the refrigerant by heat exchange between the refrigerant after passing through the condenser and the combustion air in the heat exchange section, even when the combustion air is operated under overload. Can be done. In addition, local improvement of the refrigerant circulation path and the intake path is sufficient, and the problems that could not be solved by cooling the intake air appropriately based on the intake air temperature as in the conventional case shown in the references can be improved. It has now been possible to reliably and sufficiently suppress combustion defects and increases in exhaust temperature caused by engine operation under load, while creating an advantageous state in terms of structure and running costs.

Additionally, the cited method cools the intake air temperature even when the exhaust temperature is within the appropriate temperature range and the intake air temperature is above the set value (that is, when there is no abnormality in the engine operating state). Therefore, this point is not only a wasteful operation, but also has the disadvantage of unnecessarily lowering the efficiency of the heat pump, which is the original function, but the configuration of the present invention eliminates this disadvantage. It also has an effect.

Embodiments of the present invention will be described below based on the drawings.

As shown in FIG. 1, the refrigeration cycle of an engine-driven heat pump is configured by pumping pressurized refrigerant from a compressor 3 connected to an engine 1 via a clutch 2 to a condenser 4, an expansion valve 5, and an evaporator. 6 and the compressor 3.

In this heat pump, the latent heat of condensation of the refrigerant during heat exchange in the condenser 4 is used as a heating source for heating or hot water supply, or the latent heat of vaporization of the refrigerant during heat exchange in the evaporator 6 is used for cooling. Or it can be used as a cooling source for freezing.

Therefore, a part of the refrigerant passage between the condenser 4 and the expansion valve 5 and the refrigerant passage between the evaporator 6 and the compressor 3 is connected to the engine 1.
An intake pipe 7 connected to the intake manifold 1A of
Bypass passage 9 with throttle device 8 passing through
A pipe portion of the bypass passage 9 located inside the intake pipe 7 cools the combustion air taken into the engine 1 by heat exchange with the refrigerant after passing through the condenser 4, and cools the refrigerant. It constitutes a heat exchange section 10 that evaporates.

A sensor 11 is provided to detect when the exhaust gas of the engine 1 has risen to a set temperature (for example, 450° C.) or higher, and a sensor 11 is provided in the bypass path 9 on the upper side of the throttle device 8 in the direction of refrigerant flow.
an electromagnetic valve 13 that is automatically and reversibly opened based on the detection operation of the expansion valve 12 and the sensor 11;
is intervening.

When the temperature of the exhaust gas from the engine 1 rises above the set temperature, the solenoid valve 13 activates the sensor 11.
is automatically opened based on the detection result, and a part of the refrigerant after passing through the condenser 4 is supplied to the heat exchange section 10 through the bypass path 9. Since the combustion air can be cooled by using the latent heat of vaporization of the refrigerant through heat exchange in the heat exchange section 10, overload operation in a high temperature atmosphere or moderate temperature atmosphere (of course, overload operation in a high temperature atmosphere is also included) ), it is possible to avoid poor combustion and increases in exhaust temperature caused by engine operation.

The diaphragm device 8 is composed of a capillary tube.

In addition, a proportional control valve is used in place of the open/close type solenoid valve 13, and the detected temperature of the exhaust gas and the set temperature are compared and amplified, and the proportional control valve 13 is operated based on the comparison result. The operation may be controlled to adjust the amount of refrigerant supplied to the heat exchanger 10.

FIG. 2 shows another embodiment, in which the heat exchange section 10
A bypass passage 9 having a An electromagnetic three-way valve 14 that can be switched cyclically and reversibly is interposed therebetween. In this case, since the combustion air can be cooled by the low-temperature saturated or superheated vapor refrigerant at the outlet of the evaporator 6, the number of expansion valves 12 can be reduced compared to the above embodiment.

Incidentally, although reference numerals are written in the claims section for convenient comparison with the drawings, the present invention is not limited to the structure shown in the accompanying drawings.

[Brief explanation of drawings]

FIG. 1 is a piping system diagram of an engine-driven heat pump, and FIG. 2 is a piping system diagram showing another embodiment. DESCRIPTION OF SYMBOLS 1... Engine, 3... Compressor, 4... Condenser, 5... Expansion valve, 6... Evaporator, 10... Heat exchange part, 11... Detection device.

Claims (1)

[Claims] 1. An engine-driven heat pump configured to circulate pressurized refrigerant from a compressor 3 driven by an engine 1 through a condenser 4, an expansion valve 5, an evaporator 6, and the compressor 3, A heat exchange section 10 is provided that can cool the combustion air taken into the engine 1 by heat exchange with the refrigerant after passing through the condenser 4, and the heat exchange section 10 has an engine exhaust temperature set. An engine-driven heat pump characterized in that the engine-driven heat pump is configured to automatically switch to the cooling action state based on the detection result of the detection device 11 that detects that the temperature has increased above the above level.