JPS6121552Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a cooling system for an internal combustion engine, which is intended to improve the output of the engine, especially during high loads.

An example of a conventional cooling system for an internal combustion engine is shown in FIG.

In FIG. 1, white arrows indicate the flow of cold coolant, and black arrows indicate the flow of heated coolant. The coolant that has dissipated heat in the radiator 1 passes through the radiator lower hose 2 and is forcibly pumped by the water pump 3 to the cylinder block water jacket 5 in the cylinder block 4.
Here, the coolant absorbs heat from the cylinder wall, etc., and becomes a heated coolant. The heated cooling fluid enters the cylinder head water jacket 7 in the cylinder head 6,
From here, it passes through the intake manifold water jacket 8 and heats the intake air flowing inside the intake manifold, and a portion of the heated cooling fluid in the cylinder head water jacket 7 is returned to the water pump 3 via the bypass passage 9. It will be done. Two thermostats, a low-temperature thermostat 10 and a high-temperature thermostat 11, are arranged within the intake manifold water jacket 8, and are located at an intermediate position between the two thermostats, and are opened and closed depending on the degree of engine suction negative pressure. A thermostat switching valve 12 is provided, and a bypass passage 13 connected to the thermostat switching valve 12 and the outlet side of the high temperature thermostat 11 are joined to a radiator upper hose 14 to transfer the heated cooling liquid to the radiator 1. send to.

Although not directly related to other cooling devices, the heated cooling liquid in the cylinder block water jacket 5 is transferred to the heater 16 through the opening/closing operation of the heater switching valve 15.
The cooled coolant from the heater 16 joins with some of the cooled coolant from the intake manifold water jacket 8 and flows through the bypass passage 17 to the radiator lower hose 2. be returned.

The above coolant is forcibly circulated by the water pump 3.

The thermostat switching valve 12 opens and closes depending on the engine load, that is, the degree of suction negative pressure, and switches between the low-temperature type thermostat 10 and the high-temperature type thermostat 11. When the engine is under low load, the suction negative pressure is large and the thermostat switching valve 12 is closed. Therefore, the high-temperature thermostat 11 is involved in opening and closing the heating and cooling fluid, and the temperature of the cooling fluid becomes high. On the other hand, when the engine is under high load, the suction negative pressure decreases,
Since the thermostat switching valve 12 is opened, the coolant temperature is controlled by the operation of the low-temperature thermostat 10, the coolant temperature becomes low, and the amount of coolant circulated to the radiator 1 increases.

However, in such a conventional internal combustion engine cooling system, although the thermostatic switching valve 12 controls the coolant temperature at low load and high load, the cylinder block water jacket 5 Since a part of the heated cooling fluid is circulated from the bypass passage 9 to the cylinder block water jacket 5 via the water pump 3, the engine rotational speed is particularly low when changing from a low load to a high load. When rapid acceleration is performed in a low-temperature condition, the amount of coolant circulating through the radiator 1 is small, and cooling of the engine by the coolant cooled by the radiator 1 starts from the cylinder block side, and cooling of the intake manifold begins. Because of the delay, the temperature of the heated cooling fluid passing through the intake manifold jacket 8 for heating the intake air cannot be lowered quickly. For this reason, when the degree of heating of the intake air changes from low load to high load, the heating level of the intake air does not decrease quickly and remains highly heated.The temperature of the intake air is high, the actual intake air amount decreases, and the output There were problems such as a decrease in performance and occurrence of knocking for a long time.

This idea was developed by focusing on these conventional problems, and uses a coolant passage switching valve and a cylinder block bypass passage that open when the suction negative pressure decreases during high engine loads. The purpose of the present invention is to solve the above-mentioned problems by directly guiding the cooled coolant from the radiator to the intake manifold water jacket to quickly cool the intake manifold water jacket.

This invention will be explained below based on the drawings.

FIG. 2 is a diagram showing an embodiment of this invention.

In FIG. 2, the structures and functions of reference numbers 1 to 17 are substantially the same as those of the conventional device shown in FIG.

The difference from the conventional device of this invention is that a coolant passage switching valve 18 and a cylinder block bypass passage 19 are added to the discharge side of the radiator 1, for example, the discharge side of the water pump 3, and this bypass passage 1
9 is connected to the intake manifold water jacket 8. Coolant passage switching valve 1
Similarly to the thermostatic switching valve 12, the valve 8 is opened and closed by suction negative pressure.

To explain the operation, when the engine has a low load and the suction negative pressure is large, the coolant passage switching valve 18 is closed, and the cooling fluid passage switching valve 18 and the thermostat switching valve 12 and the two thermostats 10 and 11 are closed. The method of controlling the coolant temperature is the same as before.
The heated coolant in the intake manifold water jacket 8 is maintained at a high temperature, the intake air is sufficiently warmed, the fuel is sufficiently vaporized and atomized, and the fuel and intake air are well mixed and distributed.

When the accelerator is depressed and the operation shifts from low load operation to high load operation, the suction negative pressure decreases, the thermostat switching valve 12 closes, and the low-temperature thermostat 10 operates to reduce the amount of coolant circulating to the radiator 1. increases and the coolant is kept at a low temperature.
At the same time, the coolant passage switching valve 18 also opens due to the small suction negative pressure, and the cold coolant pumped from the radiator 1 by the water pump 3 is directly supplied into the intake manifold water jacket 8 via the cylinder block bypass passage 19. be done. Therefore, the coolant in the intake manifold water jacket 8 is quickly cooled down, reducing the degree of heating of the intake air, and therefore, during high load transitions, the temperature of the intake air decreases and the actual amount of intake air increases. This prevents a decrease in engine output and also reduces the occurrence of knocking.

In the above embodiment, a change in the engine load is detected as the magnitude of the suction negative pressure, and the coolant passage switching valve 18
The switching valves 12 and 12 are controlled to open and close, and changes in load are detected as signals such as the throttle opening or intake air amount and engine speed, and this detection signal is used to control the opening and closing of the switching valves 12 and 12. 1
It goes without saying that 8 may be controlled.

As explained above, according to this invention, a cylinder block bypass passage is provided to directly guide the coolant from the radiator to the intake manifold water jacket via the coolant passage switching valve that opens and closes depending on the engine load. When the engine is under high load, the coolant passage switching valve is opened to direct the cooled coolant from the radiator to the intake manifold water jacket, which quickly cools the intake manifold water jacket. At the time of transition to load operation, the intake air becomes low temperature and the actual intake air amount increases, preventing a decrease in engine output and reducing the occurrence of knocking.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an example of a conventional cooling system for an internal combustion engine, and FIG. 2 is a block diagram of an embodiment of the cooling system for an internal combustion engine according to the present invention. 1...Radiator, 3...Water pump,
5...Cylinder block water jacket, 7
...Cylinder head water jacket, 8...
Intake manifold water jacket, 1
0...Low temperature type thermostat, 11...High temperature type thermostat, 12...Thermostat switching valve,
18...Cooling fluid passage switching valve, 19...Cylinder block bypass passage.

Claims (1)

[Claim for Utility Model Registration] Depending on the engine load, coolant from the radiator is supplied to the cylinder water jacket, and part of the heated coolant is returned to the discharge side of the radiator, and the remaining coolant is A cooling system for an internal combustion engine that controls the temperature of the coolant by circulating the liquid through the intake manifold jacket to the radiator, which includes a switching valve that is installed on the discharge side of the radiator and opens and closes depending on the engine load; and a bypass passage that directly guides a portion of the coolant from the radiator to the intake manifold water jacket through the bypass passage, and when the load of the engine is low, the switching valve closes and the coolant from the radiator is circulated through the flow path, and the engine An internal combustion engine characterized in that when the load is high, a switching valve opens, a part of the coolant from the radiator is guided to the intake manifold water jacket via the bypass passage, and the remaining coolant is distributed through the circulation path. cooling system.