JPH02191815A - Intake air cooling device - Google Patents

Abstract

PURPOSE:To make it possible to follow up change of operation condition of an engine so as to cool intake air with a good response by cooling intake air which flows from a bypass line by an evaporator according to the operation condition thereof. CONSTITUTION:When a specified and accelerated operation condition of an engine 1 is detected in an electronic controller 20, a clutch is turned OFF to stop the operation of a compressor 11, while a damper actuator is actuated to open the dampers 9a, 9b, and thus a part of intake air is supplied to the engine 1 through the bypass line 5. Intake air passing through the bypass line 5 is cooled by an evaporator 12 which has already cooled enough at the time of decelerating so that the output of the engine 1 is improved by the increase in a charging efficiency. Since the compressor 11 is not actuated, the increased engine output is used for acceleration.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an intake air cooling device that cools intake air of an engine using an evaporator of a car cooler.

(Prior art) The intake air of an internal combustion engine is heated or cooled using high-temperature refrigerant from a car cooler compressor and low-temperature refrigerant after passing through a condenser, thereby improving fuel efficiency and warm-up performance. 2. Description of the Related Art An intake air cooling device for an internal combustion engine is known from, for example, Japanese Patent Laid-Open No. 62-218618.

FIG. 6 shows such a conventional intake air cooling system, in which an evaporator 12 of a car cooler 10 is disposed in a surge tank 3 disposed midway through an intake passage 2 of an engine 1.

In addition to this F1' volator 12, the car cooler 10 is composed of an evaporator 13 for the vehicle interior, a compressor 1), a condenser 14, etc., and electromagnetic control valves 15 and 16.
The refrigerant pressurized by the compressor 1) is then switched and supplied to the evaporators 12 and 13 via the condenser 14, and then returned to the compressor 1) again to repeat the refrigeration cycle. During high-load operation of the engine 1, when the control valve 15 is opened and the control valve 16 is closed to supply refrigerant from the condenser 14 to the evaporator 12 in the direction of the arrow, the refrigerant in the evaporator 12 cools the intake air. , the intake air temperature decreases,
The charging efficiency is improved and the engine output or fuel efficiency is improved. Moreover, when the above-mentioned refrigerant is circulated in the direction opposite to the arrow, the evaporator 12 functions as a heater, heating the intake air during cooling the machine and improving the warm-up characteristics. In addition, in the figure, reference numeral 6 is a throttle valve, 7 is an air cleaner, and 8 is a throttle valve.
is the intake valve.

(Problems to be Solved by the Invention) Such conventional intake air cooling devices cool the intake air during high loads, and are therefore highly effective in improving output characteristics or fuel economy characteristics. Providing a large evaporator 12 is rather a disadvantage because it increases pumping loss at low loads.

Furthermore, the operating conditions in which it is desired to cool the intake air are not limited to the above-mentioned high load conditions, but are also required during acceleration and when knocking occurs. When accelerating or when knocking occurs, the intake air must be cooled rapidly. Also, if the intake air is overcooled during low load or idling, it may cause poor combustion or misfire, resulting in decreased output or wandering. Therefore, there is a need for an intake air cooling system that is highly responsive to changes in engine operating conditions that adversely affect gas properties.

The present invention has been made in view of such demands, and includes providing a bypass passage for bypassing a portion of intake air in the intake passage of an internal combustion engine, disposing an evaporator of a car cooler in the bypass passage, and disposing the evaporator in the bypass passage. Valve means for adjusting the amount of air flowing in, and sensor means for detecting the engine operating state are provided, and the valve means is opened and closed according to the engine operating state detected by the sensor means to control the intake air flowing through the bypass passage. An intake air cooling device is provided that is characterized by cooling using an evaporator.

Preferably, the sensor means includes a load sensor that detects the load state of the engine, and when the engine is in a predetermined high load operating state, the valve means is opened and the intake air flowing through the bypass passage is cooled by the evaporator.

Preferably, the car cooler includes a compressor that is driven by the output shaft of the engine via a clutch device and circulates refrigerant in a refrigeration circuit including the evaporator, and the sensor means detects acceleration/deceleration states of the engine. Sensor means are included. When a predetermined deceleration state of the engine is detected by the sensor means, the clutch device is turned on with the valve means closed, and the compressor is operated to cool the evaporator. Then, when a predetermined acceleration state is detected, the valve means is opened and the intake air flowing through the bypass passage is cooled by the evaporator.

Furthermore, preferably, the sensor means includes a knock sensor that detects a non-king state of the engine, and when the engine is in a predetermined knock state, the valve means is opened and the intake air flowing through the bypass passage is cooled by the evaporator. .

(Operation) When the sensor means detects an engine operating state that requires cooling the intake air, the valve means is opened and the intake air flowing through the bypass passage is cooled by the evaporator. Therefore, when the valve means is closed, the intake air does not pass through the evaporator, so no fluid resistance due to the evaporator, that is, no pump loss occurs.Furthermore, the evaporator may be cooled with a refrigerant in advance, and the valve means does not pass through the evaporator. Cooling of intake air starts at the same time as opening.

(Example) An example of the present invention will be described in detail below based on the drawings.

FIG. 1 shows a schematic configuration of an air cooling device according to an embodiment of the present invention, and the same components as those of a conventional intake air cooling device are denoted by the same reference numerals, and detailed explanation thereof will be omitted.

The intake air cooling system of this embodiment differs from conventional intake air cooling systems in that the evaporator 12 of the car cooler IO is disposed in the bypass passage 5. More specifically, the intake passage 2
A bypass passage 5 is provided which branches downstream of the throttle valve 6 and joins again near the intake boat to bypass a portion of the intake air. A surge tank 3° is disposed in the middle of this bypass passage 5, and an evaporator IO is disposed within this surge tank 3°. Bypass passage 5
Dampers (valve means) 9a and 9b for opening and closing the bypass passage 5 are disposed near each branch point and confluence point, respectively.

In addition, the compressor II of the car cooler 10 and the engine L
It is connected to an output shaft (not shown) via a clutch 21 (see FIG. 2), and its operation is controlled by turning the clutch 21 on and off.

This compressor may be of the swash plate type, and in the case of the swash plate type, the circulating amount of refrigerant is determined by adjusting the swash plate angle.

Figure 2 shows how to control the operation of the intake air cooling system shown in Figure 1.
The configuration of an electronic control unit (ECU) 20 is shown, and the input terminal of this electronic control unit 20 is equipped with various sensor means for detecting engine operating conditions, such as a rotation speed sensor 24 for detecting engine rotation speed, A negative pressure sensor 25 that detects negative pressure, an intake air temperature sensor 26 that detects intake air temperature, an outside air temperature sensor 27 that detects the outside temperature of the vehicle, a vehicle speed sensor 28 that detects vehicle speed, an air conditioner switch 29 that detects the operating state of the air conditioner, An idle switch 30 that detects the fully closed state of the throttle valve 6, a knock sensor 31 that is attached to the cylinder block of the engine 1 and detects abnormal combustion in the cylinder, and the like are connected thereto. On the other hand, the electronic control device 20
The above-mentioned compressor 1.1 and engine 1 are installed on the output side of
an electromagnetic clutch 21 interposed between the output shafts of the actuators 34 and 35 that open and close the dampers 9a and 9b, respectively;
, is installed in the middle of the refrigeration circuit, and the refrigerant is supplied to the evaporator 12 in the surge tank 3'' and the evaporator 1 in the vehicle interior.
Control valves 15, 16, etc. for switching between 3 and 3 are connected respectively.

As will be described in detail later, the electronic control device 20 controls the operation of the actuators 34 and 35 of the dampers 9a and 9b, the on/off control of the clutch 21, and the control valve 15 based on the engine operating state detected by the various sensors described above.
．． 16 opening/closing control, etc.

FIG. 3 shows a first aspect of the intake air cooling routine executed by the electronic control device 20, in which the electronic door device 20 performs step S
At step 30, it is determined whether the engine l is in a predetermined high load operating state. This determination is made using, for example, the engine speed detected by the engine speed sensor 24 and the negative pressure sensor 25.
It is determined whether the engine 1 is in a high-load operating state according to the intake negative pressure detected by the engine 1. Instead of this determination, the high-load operating state may be determined based on the engine speed, throttle valve opening, engine speed, intake air amount, etc.

When the engine l is not in a predetermined high load operating state, i.e.
When the engine is in a low load operating state and the determination result in step S30 is negative (No), the damper actuators 34 and 35 are operated to close the dampers 9a and 9b and block the flow of intake air in the bypass passage 5 (step 331). ),At this time,
You may close the control valve 15 and open the control valve 16 to stop the supply of refrigerant to the evaporator 12, or you may keep the control valve 15 open and supply refrigerant until the evaporator 12 reaches a low temperature. You can stay there.

When a low load operating state of the engine 1 is detected, the intake air supply route is quickly switched and all of the intake air is supplied to the engine I via the intake passage 2. There is no risk of excessive cooling resulting in poor combustion or misfire.

On the other hand, when a predetermined high-load operating state of the engine 1 is detected, that is, the determination result in step S30 is affirmative (Yes).
), the damper actuators 34, 35 are operated to open the dampers 9a, 9b, and a portion of the intake air is supplied to the engine 1 via the bypass passage 5 (step 53).
2) At this time, the intake air passing through the bypass passage 5 is cooled by the evaporator 12, thereby increasing the filling efficiency and improving the output.

Note that the evaporative lake 12 is provided with a bypass passage 5,
Since it is installed in this passage, the evaporator 1
There is no pump loss due to fluid resistance as described in 2. At high loads, the output improvement outweighs this pump loss, and the output improvement is a great advantage. Depending on the cooling water temperature, intake air temperature, outside air temperature, etc., intake air cooling may be prohibited even when the engine I is in a high load operating state, or the high load operating range 9n in which intake air should be cooled may be changed.

FIG. 4 shows a second aspect of the intake air cooling routine executed by the electronic control device 20, in which the electronic control device 20 performs step 3.
At step 40, it is determined whether the engine 1 is in a predetermined deceleration operating state. This determination is made, for example, between the vehicle speed detected by the vehicle speed sensor 28 or a predetermined speed (for example, 301u+
C) or more, the throttle valve 6 is in a fully closed state by the idle switch 30, and the engine rotation speed is a predetermined rotation speed (for example, 1200 rpm) or more. It is determined that the vehicle is in a deceleration state.

When the engine l is in this predetermined deceleration operating state, that is, when the determination result in step S30 is affirmative, the damper actuators 34, 35 are actuated and the dampers 9a, 9
b to block the flow of intake air in the bypass passage 5, and at the same time turn on the clutch 21 to turn on the compressor 1).
, open the control valve 15 and close the control valve 16 to supply refrigerant to the evaporator 12 (
Step 542), whereby the evaporator 12 disposed in the bypass passage 5 is cooled during deceleration operation.

Next, if the determination result in step S40 is negative, the process proceeds to step S43, where it is determined whether or not the engine 1 is in a predetermined accelerated operating state. This determination may be made, for example, by the engine speed detected by the engine speed sensor 24 and the intake negative pressure detected by the negative pressure sensor 25, or by providing a throttle sensor that detects the opening degree of the throttle valve 6. The determination may be made based on the opening degree of the throttle valve 6 or the valve opening speed.

If the engine 1 is not in this predetermined acceleration operation state, the process advances to step S45, and the dampers 9a and 9b are kept closed.At this time, the clutch 21 is kept turned on.
Although the refrigerant may be sent to the evaporator 13 for the vehicle interior, if there is no need to cool the vehicle interior, the clutch 21 is turned off to stop cooling the evaporator 12.

When a predetermined acceleration operating state of the engine 1 is detected, the process proceeds to step 346, where the clutch 21 is turned off to disable the compressor 1), and the damper actuator 34, 35 is actuated to drive the damper 9a. , 9b are opened and a portion of the intake air is supplied to the engine l via the bypass passage 5.

At this time, the intake air passing through the bypass passage 5 is cooled by the evaporator 12, which has been sufficiently cooled during deceleration, and the output is improved by increasing the filling efficiency. Also, since the compressor 1) is made inoperative, the engine output can be used for acceleration accordingly.

In this way, during deceleration, part of the deceleration energy of the engine 1, which was previously wasted, is used to reduce the energy consumption of the compressor 1).
The engine operates to cool the evaporator 12, and during acceleration and deceleration, the intake air is cooled using the heat capacity that cools the evaporator I2, thereby improving output, resulting in energy savings and improved fuel efficiency.

Note that the intake air during acceleration is not only cooled by the heat capacity of the cooling fins of the evaporator 12, but also the cooling of the evaporator 12 during deceleration causes many water droplets attached to the surface of the evaporator lake 12 to evaporate during acceleration. It is also done by Since the latent heat of vaporization of these water droplets is large, the intake air can be sufficiently cooled over a long period of accelerated operation, although it depends on the capacity of the evaporator 12.

FIG. 5 shows a third aspect of the intake air cooling routine executed by the electronic control device 20, in which the electronic control device 20 performs step S
At 50, the amount of knock is detected based on the knock signal from the knock sensor 1). Next, the detected amount of knock is compared with a reference value, and it is determined whether or not the amount of knock of the engine 1 is large (step 351). When the amount of knock is smaller than the reference value, the dampers 9a and 9b are closed. At this time, if the evaporator 12 in the bypass passage 5 is not sufficiently cooled, open the control valve 15 and close the control valve 16 to send refrigerant to the evaporator 12 to cool it sufficiently. Keep it cool.

On the other hand, if it is determined in step 351 that the knock amount of the engine 1 is greater than the reference value, step 352 is immediately executed and the damper 9a is removed.

9b is opened to allow a portion of the intake air to flow into the bypass passage 5 to cool it and avoid knocking. Conventionally, when the amount of knock is large, for example, the ignition timing is retarded, but this embodiment deals with this by cooling the intake air. This increases the knock limit and makes it possible to avoid knocking without reducing the output of the engine 1.

In the above-described embodiment, the dampers 9a and 9b were disposed near the branching point and the merging point of the bypass passage 5, but the present invention is not limited thereto, and either one of these may be omitted.
It is also possible to arrange one damper in the middle of the bypass passage 5.

(Effects of the Invention) As described in detail above, according to the intake air cooling device of the present invention, the intake passage of an internal combustion engine is provided with a bypass passage that bypasses a part of the intake air, and the bypass passage is provided with a kartara. An evaporator is provided, and a valve means for regulating the amount of air flowing into the bypass passage, and a sensor means for detecting the engine operating state are provided, and the valve means is adjusted according to the engine operating state detected by the acid sensor means. Since the intake air that opens and closes and flows through the bypass passage is cooled by the evaporator, the intake air can be cooled responsively by following changes in engine operating conditions, increasing charging efficiency when the engine is operating under high load. The increased output can avoid misfires and poor combustion during low-load operation. Furthermore, by using part of the deceleration energy during deceleration to sufficiently cool the evaporator and using this to cool the intake air during acceleration, energy can be saved and fuel efficiency characteristics can be significantly improved. Furthermore, even when knocking occurs, one inlet air can be quickly cooled, so that various excellent effects can be achieved, such as being able to avoid knocking without delaying the ignition timing as in the conventional case.

[Brief explanation of the drawing]

1 is a schematic configuration diagram of an intake air cooling device according to an embodiment of the present invention, FIG. 2 is a prong diagram showing the configuration of an electronic control device that controls the intake air cooling device shown in FIG. 1, and FIG. The figure shows the first am of the intake air cooling routine executed by the electronic control unit.
FIG. 4 is a flowchart showing a second aspect of the intake air cooling routine executed by the electronic control device, FIG. 5 is a flowchart showing the third aspect of the intake air cooling routine executed by the electronic control device, and FIG. The figure is a schematic configuration diagram of a conventional intake air cooling device. DESCRIPTION OF SYMBOLS 1... Internal combustion engine, 2... Intake passage, 5... Bypass passage, 10... Carterara, 1)... Compressor, 12... Evaporator, 13... Vehicle interior evaporator, 14 ...Capacitor, 15.16...
Control valve, 20...Electronic control device, 21...
Clutch, 24... Engine speed sensor, 25...
-Negative pressure sensor, 31...knock sensor. Applicant Mitsubishi Motors Corporation Agent Patent Attorney Kan Nagato Figure 2 Figure 4 Figure 5

Claims (4)

[Claims] (1) A bypass passage for bypassing a portion of intake air is provided in the intake passage of an internal combustion engine, an evaporator of a car cooler is disposed in the bypass passage, and a valve means for regulating the amount of air flowing into the bypass passage. , a sensor means for detecting an engine operating state, and the valve means is opened and closed according to the engine operating state detected by the sensor means, and the intake air flowing through the bypass passage is cooled by the evaporator. Air cooling device. (2) The sensor means includes a load sensor that detects the load state of the engine, and when the engine is in a predetermined high load operating state, the valve means is opened and the intake air flowing through the bypass passage is cooled by the evaporator. The intake air cooling device according to claim 1, characterized in that: (3) The car cooler includes a compressor that is driven by the output shaft of the engine via a clutch device and circulates refrigerant in a refrigeration circuit including the evaporator, and the sensor means detects acceleration/deceleration states of the engine. When a predetermined deceleration state of the engine is detected by the sensor means, the clutch device is turned on with the valve means closed, the compressor is operated to cool the evaporator, and the predetermined deceleration state is detected. 2. The intake air cooling device according to claim 1, wherein when an acceleration state of the engine is detected, the valve means is opened and the intake air flowing through the bypass passage is cooled by the evaporator. (4) The sensor means includes a knock sensor that detects a knocking state of the engine, and when the engine is in a predetermined knocking state, the valve means is opened and the intake air flowing through the bypass passage is cooled by the evaporator. The intake air cooling device according to claim 1, characterized in that: