JP2640190B2 - Engine cooling system for heat recovery type engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling device for a water-cooled engine used in a waste heat utilizing device such as a heat pump device.

[0002]

2. Description of the Related Art Conventionally, a cooling device for a water-cooled engine used in this type of device is configured such that a high-temperature cooling water channel derived from a water jacket of the water-cooled engine is connected to a radiator through an exhaust gas heat exchanger, and cooling water is returned from the radiator. To the water jacket of the water-cooled engine via the cooling water pump,
The high-temperature cooling water passage between the exhaust gas heat exchanger and the radiator and the cooling water return passage upstream of the cooling water pump are connected via a temperature-sensitive flow switching valve such as a thermostat valve arranged in the high-temperature cooling water passage. When the temperature of the cooling water flowing through the exhaust gas heat exchanger is lower than the set temperature of the temperature-sensitive flow path switching valve, the cooling water is returned from the short circuit to the water-cooled engine, and then flows from the exhaust gas heat exchanger. When the temperature of the cooling water is higher than the operation set temperature of the temperature-sensitive flow switching valve, high-temperature cooling water is supplied to the radiator.

[0003]

However, the radiator in the conventional heat pump device is composed of a radiator for releasing the heat retained in the engine cooling water and a radiator for exchanging heat between the engine cooling water and the cold water. The radiator used for cooling and heating is selected, and the air from one blower fan arranged for both radiators acts on the radiator to cool the engine. Although it is configured to take heat from water, this blower fan starts operating at the same time as switching of the temperature-sensitive flow path switching valve arranged in the high-temperature cooling water passage, so the cooling water returned to the engine is There has been a problem that the temperature greatly varies before and after switching of the temperature-sensitive flow path switching valve. The present invention has been made in view of such a point, and an object of the present invention is to provide a cooling device for a heat recovery type engine in which fluctuations in engine inlet water temperature of cooling water are small.

[0004]

In order to achieve the above object, the present invention circulates engine cooling water through an exhaust gas heat exchanger, a radiator, and a cooling water pump to bypass the radiator. Place the short circuit in the state, place a temperature-sensitive flow switching valve at the connection between the inlet of the radiator and the short circuit,
In an engine cooling device configured to selectively select a radiator and a short circuit path to flow cooling water, an electric blower fan is arranged corresponding to the radiator, and the electric blower fan is connected to the radiator. The operation is started by detecting the temperature of the cooling water flowing into the air blower, and the operation start temperature of the electric blower fan is set higher by a predetermined temperature than the switching set temperature by the temperature-sensitive flow path switching valve. .

[0005]

According to the present invention, the engine cooling water is circulated through an exhaust gas heat exchanger, a radiator, and a cooling water pump, and a short circuit is arranged in a state of bypassing the radiator.
In a cooling device for an engine, a temperature-sensitive flow path switching valve is disposed at a connection portion between an inlet of a radiator and a short circuit, and a cooling water is caused to flow by selectively selecting a radiator and a short circuit. An electric blower fan is arranged corresponding to the radiator, and the electric blower fan is configured to operate by detecting a cooling water temperature flowing into the radiator, and to sense an operation start temperature of the electric blower fan. The temperature of the cooling water flowing through the exhaust gas heat exchanger reaches the predetermined temperature because the temperature is set higher than the switching set temperature by the warm flow path switching valve, and the flow path of the cooling water changes from the short circuit path to the radiator. Since the cooling water temperature did not reach the operation start temperature of the electric blower fan at the beginning of the
Since the blower fan does not operate and the cooling water emits heat by natural cooling in the radiator, the temperature of the cooling water returning to the engine does not drop sharply. Then, when the cooling water temperature reaches the operation start temperature of the electric blower fan, the blower fan operates to be in a forced cooling state, so that heat is taken from the cooling water.

[0006]

1 shows an embodiment of the present invention, and FIG. 1 is a block diagram showing an engine cooling water circulation system in an engine heat pump. This engine heat pump has a compressor (1) for compressing a heat medium of a cooling and heating device, and a water-cooled engine (2) for driving the compressor (1).

[0007] The cooling system of the water-cooled engine (2) is a high-temperature cooling water channel derived from a water jacket of the water-cooled engine (2).
(3) is connected to the radiator (5) via the exhaust gas heat exchanger (4), and the cooling water return path (6) from the radiator (5) is connected to the engine through the cooling water pressure pump (7). The cooling water is circulated by being connected to a water jacket, and a temperature-sensitive flow switching valve (8) for switching a flow path when the cooling water temperature reaches a predetermined temperature (T ₀ ) in the high-temperature cooling water path (3). A thermostat valve (9) is disposed, and a short-circuit path (10) derived from the thermostat valve (9) is connected to a cooling water return path (6) upstream of the cooling water pressure pump (7).

An electric blower fan (11) is arranged in correspondence with the radiator (5), and the downstream side of the thermostat valve (9) of the high-temperature cooling water channel (3) is upstream of the radiator (5). Temperature detector that detects the temperature of the cooling water flowing into the radiator (5) on the side
(12) is arranged, and the temperature of the cooling water flowing into the radiator (5)
The electric blower fan (11) is configured to operate based on the temperature detector (12) detecting that (T ₁ ) has become equal to or higher than the set temperature.

The set operating temperature of the electric blower fan (11)
(T ₁ ) is the set temperature (T ₀ ) of the channel switching of the thermostat valve (9).
It is set at a slightly higher temperature. In the present embodiment, the set temperature (T ₀ ) of the thermostat valve (9) is set to 70 ° C.
And set the operation set temperature (T ₁ ) of the electric blower fan (11).
Is set to 75 ° C.

FIG. 2 shows another embodiment of the present invention in which a high-temperature cooling water passage (3) and a cooling water return passage (6) are connected to a short-circuit passage (10) upstream of a cooling water pump (7). ), And a solenoid on-off valve (13) on the downstream side of the short-circuit path connection of the high-temperature cooling water path (3).
And an electromagnetic on-off valve (14) also on the short-circuit path (9), and flows into the water jacket of the engine (2) near the return port of the cooling water return path (6) to the engine (2). A temperature detector (15) for detecting the temperature of the cooling water to be cooled is provided, and both solenoid on-off valves are provided based on the temperature of the cooling water detected by the temperature detector (15).
(13) (14) is configured to be selectively opened and closed, so that both solenoid on-off valves (13) and (14) can be used with the temperature-sensitive flow switching valve.
(8) is constituted. When the temperature of the cooling water flowing into the engine is equal to or lower than a predetermined temperature, the electromagnetic on-off valve (14) interposed in the short-circuit path (10) is opened and the high-temperature cooling water path (3) is interposed. If the temperature of the cooling water flowing into the engine is equal to or higher than a predetermined temperature, the electromagnetic on-off valve (13) interposed in the short-circuit path (10) is closed. In addition, the electromagnetic on-off valve (13) interposed in the high-temperature cooling water passage (3) is configured to be opened.

A radiator (5) is disposed in the high-temperature cooling water channel (3) downstream of the electromagnetic on-off valve (13).
An electric blower fan (11) is disposed corresponding to the temperature, and a temperature detector (12) for detecting the temperature of cooling water flowing into the radiator (5) between the electromagnetic on-off valve (13) and the radiator (5). Are arranged, and the operation of the electric blower fan (11) is controlled based on the temperature detected by the temperature detector (12).

The operation set temperature (T ₁ ) of the electric blower fan (11) is determined by the flow switching set temperature (T T) of the solenoid on-off valves (13) and (14).
_The temperature is set slightly higher than ₀ ). Further, in the present embodiment, the flow path switching set temperature of the solenoid on-off valve (13) (14) is set.
(T ₀ ) is set to 70 ° C., and the operation set temperature (T ₁ ) of the electric blower fan (11) is set to 75 ° C.

In the above embodiment, the solenoid on-off valves (13) and (14)
A temperature detector (15) for controlling the opening and closing of the cooling water is provided near the cooling water return port to the engine, but this temperature detector (15) is provided at the outlet from the exhaust gas heat exchanger (4). Is also good.

[0014]

According to the present invention, the cooling water of the engine is circulated through the exhaust gas heat exchanger, the radiator, and the cooling water pressure pump, and the short circuit is arranged in a state of bypassing the radiator. In a cooling device for an engine, a temperature-sensitive flow path switching valve is disposed at a connection portion between an inlet and a short-circuit path, and a radiator and a short-circuit path are selectively selected to flow cooling water. An electric blower fan is arranged so as to correspond to the above, and the electric blower fan is configured to operate by detecting a cooling water temperature flowing into the radiator. Since the cooling water temperature flowing through the exhaust gas heat exchanger has reached the predetermined temperature because the switching temperature is set higher than the switching set temperature by the path switching valve, the flow path has been switched from the short circuit path to the radiator. Initially, the cooling water temperature was Since not reached the operation start temperature, the blower fan is not operated, the cooling water will be released heat by natural cooling in the radiator. As a result, the temperature of the cooling water returning to the engine based on the switching of the temperature-sensitive flow path switching valve does not suddenly decrease.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an engine cooling water circulation system in an engine heat pump.

FIG. 2 is a configuration diagram showing another embodiment of the engine cooling water circulation system in the engine heat pump.

[Explanation of symbols]

2 ... water-cooled engine, 3 ... high-temperature cooling channel,
4: Exhaust gas heat exchanger, 5: Radiator, 6: Cooling water return path, 7: Cooling water pressure pump, 8: Temperature-sensitive flow path switching valve, 10: Short circuit path, 11: Electric blower fan, T ₁ ... operation starting temperature of the electric blower fan, T ₀ ... switching the set temperature of the temperature-sensitive channel selector valve.

Claims (1)

(57) [Claims] 1. A high-temperature cooling water passage (3) derived from a water jacket of a water-cooled engine (2) is connected to a radiator (5) through an exhaust gas heat exchanger (4), and cooled from the radiator (5). The water return path (6) is connected to the engine water jacket via a cooling water pump (7), and the cooling water return path (6) upstream of the high temperature cooling water path (3) and the cooling water pump (7). In an engine cooling device of a heat recovery type engine in which a short circuit path (10) communicating with a radiator (5) is connected via a temperature-sensitive flow path switching valve (8), an electric blower fan ( 11), the electric blower fan (11) is configured to operate by detecting the temperature of the cooling water flowing into the radiator (5), and the operation start temperature of the electric blower fan (11) (T heat recovery engine, characterized in that the set predetermined temperature higher than the switch setting temperature of the ₁₎ in a temperature-sensitive channel selector valve (8) (T ₀₎ Of the engine cooling system.