JPS6394065A - Intake air cooler for internal combustion engine - Google Patents

Abstract

PURPOSE:To lower the temperature of supply air, by providing an independent storage tank in a cooling medium circulation path for a super charged air cooler while arranging a cooling medium path for air-conditioner in said storage tank and cooling the cooling medium in the storage tank is accordance with the operating condition. CONSTITUTION:An inter-cooler 30 for cooling the supercharged air fed from a supercharger 7 is coupled with a cooling water circulation system comprising a cooling water path 32, a cooling water pump 34, a storage tank 33, a bypath 68 and a three-way changeover valve 69. An evaporator section 33a where coolant is led in through a solenoid valve 66 from the downstream of a condenser 48 in an air-conditioner cooling medium circulation system is arranged in the storage tank 33. The cooling pump 34 and the solenoid valve 66 are controlled based on an output from a temperature sensor 77 such that the temperature of the inter-cooler cooling water will be 10 deg.C-30 deg.C, for example, while when the vehicle speed is higher than 40km/h and the opening of throttle valve is larger than 40%, the three-way changeover valve 69 is switched to lead the cooling water being sustained at low temperature to the inter-cooler 30.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an intake air cooling device for a vehicle internal combustion engine equipped with an air conditioner and equipped with a supercharger.

[Conventional technology]

In an internal combustion engine equipped with a supercharger, an intake air cooling device (so-called intercooler) is installed in order to lower the temperature of air that has increased due to adiabatic compression due to supercharging and increase output.

However, water-cooled intercoolers have the problem that they are not sufficiently effective in the summer when the outside temperature is high. Moreover, the temperature of the water, which is a cooling medium, cannot be sufficiently lowered due to the heat in the engine room, and the engine performance cannot be sufficiently increased at high supercharging. Furthermore, the intercooler's cooling capacity fluctuates due to fluctuations in the outside temperature and the heat inside the engine compartment, making it difficult to achieve stable engine performance.

In order to solve this problem, Japanese Patent Publication No. 60-35530 proposes installing a surge tank cooling device in the intake pipe that is branched from the air conditioner for cooling the passenger compartment and operates independently of the air conditioner. ing. The system attempts to powerfully cool the air from the supercharger using a low-temperature cooling medium branched from the air conditioner. The engine also includes a control circuit that detects the temperature of the intake air and operates the surge tank cooling device when the temperature exceeds a predetermined value. Other related conventional techniques include Utility Model Application Publication No. 59-91421.

[Problem that the invention seeks to solve]

In the prior art, the idea is to simply connect the refrigerant passage of the air conditioner for cooling the passenger compartment to the intake pipe and exchange heat with the intake air. Therefore, in order to sufficiently cool both the interior of the vehicle and the intake air, the cooling capacity of the cooling device must be increased. That is, in the conventional method,
It is necessary to have a cooling capacity equal to the sum of the maximum cabin cooling requirement and the maximum intake air cooling requirement.

The purpose of this invention is to solve the above-mentioned drawbacks of the prior art,
To provide sufficient cooling even though the capacity of a cooling device is limited.

This invention is based on a patent application filed by the applicant in 1986-12.
This is an improvement on No. 0240.

[Means for solving problems]

According to this invention, in an internal combustion engine for a vehicle equipped with an air conditioner, in which a supercharger is installed in the intake pipe and a water-cooled intake air cooling device is arranged downstream of the supercharger, the cooling medium for the intake air cooling device is circulated. An independent storage tank is installed in the middle of the passage, and within the storage tank, a cooling medium passage for the vehicle's air conditioner is arranged to enable heat exchange, and a bypass passage that bypasses the intake air cooling device and a cooling medium passage for the engine operating state are arranged in the storage tank. An intake air cooling device for an internal combustion engine is provided, comprising means for switching the flow direction of an air conditioner cooling medium between a bypass passage and an intake air cooling device according to the flow direction of the air conditioner cooling medium.

〔Example〕

In Figure 1, 1 is a piston, 2 is a combustion chamber, 3 is an intake valve, 3' is an exhaust valve, 4 is an intake pipe, 5 is a throttle valve, 6
is an air flow meter. 7 is a mechanical supercharger, which is installed downstream of the throttle valve 5. Mechanical supercharger 7
is configured as a Roots pump, for example, and includes a plurality of rotors 7.
Supercharging is performed by compressing intake air by rotating while maintaining a small gap with respect to the housing. A clutch-equipped boot I710 is installed on one rotating head 8 of the rotor 7a, and this pulley 10 is connected to a pulley 16 on a crankshaft 14 by a belt 12. At the time of high rotation and high load when the clutch portion of the pulley 10 is engaged, the rotation of the crankshaft 14 is transmitted to the rotor 7a via the boolean IJ 16, the belt 12, and the pulley 10, and supercharging is performed.

A bypass passage 18 is connected to the intake pipe 4 so as to bypass the supercharger 7.
connected to. A bypass control valve 20 is installed in the bypass passageway 18. This bypass control valve 20 is driven by a negative pressure actuator 22. That is, the negative pressure actuator 22 is connected to the pressure extraction port 24 downstream of the supercharger 7, and drives the bypass control valve 20 according to the intake pipe pressure. That is, when the load is low, the pressure in the port 24 is low, so the actuator 20 opens the bypass control valve 20 by negative pressure action, and a portion of the intake air flows through the bypass passage 18.
The supercharging effect by the supercharger 7 is weakened. On the other hand, when the load is high, the pressure in the port 24 is high (so the actuator 22 closes the bypass control valve 20, the intake air is fully supplied to the combustion chamber 2 via the supercharger 7, and the supercharger 7 He will demonstrate his full potential.

30 is a water-cooled intake air cooling device (hereinafter referred to as ink cooler)
It is. The ink cooler 30 is installed downstream of the supercharger 7 and upstream of the connection point of the downstream end of the bypass passage 18 to the intake pipe 4. The ink cooler 30 is located in the intake pipe and includes a heat exchange section 31 that exchanges heat by contacting intake air. The heat exchange section 31 is connected to a cooling water storage tank 33 via a cooling water passage 32, thereby forming a cooling water circulation system for the ink cooler 30. A circulation pump 34 is installed in the cooling water passage 32. As will be described later, the cooling water stored in the storage tank 33 is cooled by the cooling medium of the air conditioner. Preferably, the outer wall of the ink cooler 30 is kept warm by a heat insulating material. This is to absorb the heat of the air in the engine room heated by the radiant heat of the engine, and to prevent the water temperature from rising.

The bypass passage 18 is connected to the intake pipe 4 downstream of the intercooler 30.
connected to. Therefore, the amount of air passing through the ink cooler 30 decreases in the partial load range where supercharging is not required.
It is possible to prevent the water temperature of the intercooler 30 from rising.

The air conditioner compressor is designated by the reference numeral 44 and has a belt 46.
It is connected to the crankshaft 14 by a rotary shaft so as to receive rotating shaft power. The air conditioner compressor 44 is sequentially connected to a condenser 48, a receiver 50° expansion valve 52, and an evaporator 54 via an air conditioner cooling medium passage 56, thereby forming a circulation system for the cooling medium of the air conditioner. In the figure, the flow direction of the cooling medium in the air conditioner is indicated by a solid arrow A.

A heat exchange section 33a functioning as an evaporator is arranged in the intercooler cooling water storage tank 33 in parallel with the air conditioner evaporator 54. That is, one end of the heat exchange section 33a is connected to the receiver 5 via the expansion valve 58 and the connecting T-tube 60.
0, and the other end is connected to the downstream side of the vehicle interior evaporator 54 via a T-shaped pipe 62.

In the figure, the flow of the air conditioner cooling medium to the ink cooler is indicated by a broken line arrow B.

A first solenoid valve 64 and a second solenoid valve 66, which are on-off valves that selectively open and close the circulation of the air conditioner cooling medium, connect the passage 56 that constitutes the vehicle compartment circulation system and the storage tank circulation system, respectively. It is installed in the constituting passage 57.

According to the present invention, a bypass passage 68 is provided to bypass the intercooler 3o, and one end thereof is connected to the intercooler cooling water passage 32 by a T-shaped pipe 68a and the other end by a three-way switching valve 69. When the 3-way switching valve 69 is ON, the black port position is taken, and the cooling water from the tank 33 flows to the bypass 68 (arrow a), and when it is OFF, the white port position is taken, and the cooling water from the tank 33 is flowing to the bypass 68 (arrow a). is ink cooler 3
You can go to ゜ (arrow b).

The control circuit 70 controls various operations of the supercharger, the air conditioner, the acceleration intercooler cooling device of the present invention, and the internal combustion engine, and can be configured as a microcomputer system. That is, the control circuit 70 includes a central processing module M (CPU) 7oa, a memory 70b, and an input port door 0.
c, output port door 0d, and bus 70 connecting these
It is composed of e. Various sensors are connected to the input capo 110c in order to execute the control of the present invention, and respective detection signals are inputted thereto. An intake air amount signal is input from the air flow meter 6. A signal corresponding to the opening degree of the throttle valve 5 is input to the throttle sensor 74 . Throttle sensor 7
4 may be, for example, a well-known rotary brush that moves together with the throttle valve shaft. This type of throttle sensor 74 is a digital type that can obtain a pulse signal depending on the opening degree of the throttle valve. 76
is the air conditioner activation switch, which is usually installed in the driver's seat and is operated to cool the passenger compartment. A temperature sensor 77 is installed in the storage tank 30 in order to know the temperature of the cooling water for the intercooler 30. Furthermore, a vehicle speed sensor 79 is installed, for example at the output shaft of the transmission, for detecting the speed of the vehicle.

The output port door 0d is a clutch section for controlling the supercharger and a clutch section 44 for the air conditioner compressor 44 in the pulley 1o.
, an ink cooler cooling water circulation pump 34, a first solenoid valve 64, a second solenoid valve 66, and a three-way switching valve 69. These controls are executed according to the program stored in the memory 70b. Of these, the operation of the supercharger 7 and the operation of the air conditioner compressor 44 by turning on and off the air conditioner switch operated by the driver are not directly related to the present invention and will not be described in detail. The operation of the control circuit directly related to the present invention will be explained below with reference to the flowchart shown in FIG.

The routine of FIG. 2 can be configured as a time interrupt routine that is executed at predetermined time intervals. In step 80, it is determined whether the air conditioner operation switch 76 is turned on. Since the switch 76 is OFF when the vehicle interior is not air-conditioned, the process proceeds to step 82, and the first
Solenoid valve 64 is closed. Therefore, the flow of the cooling medium in the vehicle interior cooling medium circulation passage 56 does not occur. In step 84, it is determined whether the temperature T of the ink cooler cooling water detected by the temperature sensor 77 is a predetermined value, for example, 10° C. or higher. If T≧10℃, step 86
Then, it is determined whether the flag f^/C0FF=1. This flag is set when the compressor 44 is turned off, and reset when it is turned on. compressor 4
4 is OFF, the flag=1, and the process proceeds to step 87, where the operating clutch (not shown) of the compressor 44 is engaged. In step 88, the second solenoid valve 6
6 is released. Therefore, a circulation system for the cooling medium from the compressor 44 to the compressor 44 via the condenser 48, the receiver 50, the expansion valve 58, and the evaporator section 33a is configured (broken line B).

Therefore, the intercooler cooling water in the storage tank 33 is cooled. At the same time, the water pump 34 is activated and the three-way switching valve 69 is turned on to take the black boat position. In this way, a circulation system (arrow a) of cooling water is constructed in which the cooling water enters the cooling water tank 33 from the pump 34 and is returned through the bypass passage 68. In step 89, the flag is reset.

As a result of the operation of the compressor 44, the water temperature T is a predetermined value of 10°C.
If it falls below, step 84 advances to step 90, the compressor 44 is turned off, and then step 9
At step 2, the water pump 34 is turned off, and at step 94, a flag is set.

When the water temperature exceeds 10°C again, the process proceeds from step 84 to restep 86, but since the flag is set this time, the process proceeds to step 96, where the water temperature T is set to a predetermined value, for example 30°C.
It is determined whether or not the value is greater than or equal to the value. When T>30° C., the process proceeds to the step 87 described above, the compressor 44 is operated again, and the circulation of the intercooler cooling water in the tank 33 by the air conditioner cooling medium is restarted.

When the air conditioner switch 76 is ON, the cooling operation of the intercooler cooling water by the air conditioner cooling medium is almost the same as when the air conditioner switch 76 is OFF. Step 80 then proceeds to step 98, where the first solenoid valve 64 is opened.

Therefore, the cooling medium from the compressor 44 can go to the cabin cooling evaporator 54 (arrow A). The processing from step 100 onwards for controlling the operation of the intercooler is almost the same as the operation when the air conditioner is stopped. However, when the water temperature T is 10°C or less, the processing is different in step 100.
Since the process proceeds to step 102, the air conditioner compressor 44
is maintained in working condition.

As described above, through the processes of steps 80 to 102, the temperature T of the cooling water in the cooling water tank 33 is maintained between 10°C and 30°C, regardless of whether the air conditioner switch 76 is ON or OFF. . The operation of the intercooler according to the present invention will be explained below. At step 104 in Figure 2, the vehicle speed ■ is 40k.
m/h or more, in step 106 the throttle valve 5
It is determined whether the opening degree is 40% or more. If neither of these conditions is met, the temperature of the intake air from the supercharger 7 is high (there is no need for cooling, so step 108 is bypassed. Therefore, the 3-way valve 69 is moved to the black boat position). is maintained, and no cooling water flows to the ink cooler 30 (arrow a).

When V > 401 ua/h and TI > 40%, the engine is operating at high speed and under high load, and the intake air needs to be cooled.

In this case, the process advances to step 108, and the three-way switching valve 69 assumes the white boat position. Also, the water pump 34 is driven. Therefore, as shown by the arrow, the intercooler 3
Cooling water can be directed to the ink cooler 30 and the storage tank 33, and the air is cooled at the evaporator section 33a by the cooling water circulating through the ink cooler 30 and the storage tank 33.

〔effect〕

According to this invention, an independent storage tank 33 is provided, the tank 33 is normally separated from the intercooler 30, and cooling water is sent to the ink cooler 30 during operation that requires cooling, thereby efficiently controlling the intake air temperature. can be lowered to That is, during non-essential operations, cooling water is not sent to the intercooler 30 and the water temperature in the storage tank 30 does not rise, so the air conditioner is not turned on more than necessary, which improves the fuel consumption rate. be able to.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of an embodiment. FIG. 2 is a flow chart diagram illustrating the operation of the control circuit shown in FIG. 4... Intake pipe, 7... Mechanical supercharger, 10
...Pulley with clutch, 18...Bypass passage, 20...Bypass control valve,
30... Intercooler, 33... Storage tank, 34
...Water pump, 39...Switching valve, 44...Air conditioner compressor, 64, 66...Solenoid valve, 70...Control circuit.

Claims (1)

[Claims] In a vehicle internal combustion engine equipped with an air conditioner, in which a supercharger is installed in the intake pipe and a water-cooled intake air cooling device is placed downstream of the supercharger, an independent A storage tank is installed, and a cooling medium passage for the vehicle's air conditioner is arranged in the storage tank to enable heat exchange, and a bypass passage for bypassing the intake air cooling device and a cooling medium passage for the air conditioner are arranged in the storage tank, depending on the operating state of the engine. An intake air cooling device for an internal combustion engine, comprising means for switching the flow direction of a cooling medium between a bypass passage and an intake air cooling device.