JPS58195012A - Suction system of engine - Google Patents

Abstract

PURPOSE:To improve combustibility by providing a closing valve which is actuated over a preset load, in a high load suction passage and controlling the valve to close in accordance with reduction of engine temperature to enhance the swirl for promoting atomization and evaporation of fuel. CONSTITUTION:It is assumed that the temperature detected by a temperature sensor 23 is for example, within the range of 0 deg.C and 60 deg.C. At a low load run with an exhaust pressure under P1kg/cm<2>, a solenoid valve 28 completely opens an opening 44, in its normal position, having the operation rod 35 of a diaphragm member 27 projected to close a closing valve 14. Mixture flows through a low load suction passage 12 only and is intensively swirled. Under an intermediate load, the valve body 43 of the solenoid valve 28 comes closer to the opening 44 to throttle the opening more than in case where a detected temperature is over 60 deg.C. Since the opening of the closing valve 14 is smaller than the case where the detected temperature is over 60 deg.C, the swirl may be intensified. Under a high load, the closing valve 14 is similarly throttled more than the case where the detected temperature is 60 deg.C or more.

Description

[Detailed description of the invention] This invention relates to an engine intake system.

Conventionally, an engine intake system has been equipped with an independent low-load intake passage and a high-load intake passage at least near the combustion chamber, and the high-load intake passage is equipped with an on-off valve that opens and closes when the load exceeds a set load. , At low load with a small amount of intake air (・at low load), air is supplied only from the low load intake passage to increase the flow velocity, strengthen the swirl, and atomize the fuel.
While promoting vaporization to improve combustion performance, fuel efficiency, and drivability, at high loads with a large amount of intake air, air is supplied from the low-load intake passage and the high-load intake passage, improving charging efficiency and 1 has been proposed in order to improve the output performance (Utility Model Application No. 54-61118).

By the way, the quality of atomization and vaporization of fuel depends on the temperature of the engine. As the engine temperature increases, the fuel becomes easier to atomize and vaporize, and as the engine temperature decreases, the fuel 'F+
becomes difficult to atomize and vaporize. Therefore, when the engine temperature is low, compared to when the engine temperature is high, the set load at which the on-off valve should start to open is increased in accordance with the decrease in engine temperature, and the area where the on-off valve is closed is increased, or Correction control is performed to reduce the opening degree of the on-off valve, and the sharing ratio of the low-load intake port is increased.
It is necessary to increase the flow rate of intake air to improve fuel atomization and vaporization.

However, in the conventional engine intake system, the opening/closing valve is controlled to open and close only according to the load, regardless of the engine temperature, so that the atomization and vaporization of the fuel are poor when the engine is low temperature. Especially in the transition region from low to medium load, where the on-off valve begins to open and the amount of intake air increases, the atomization and vaporization properties of the engine deteriorate, resulting in combustibility and
This has the disadvantage that drivability and fuel efficiency deteriorate.

Therefore, an object of the present invention is to correct and control the opening timing and opening degree of the on-off valve according to the engine temperature.
It improves fuel mist and vaporization, improves combustion performance, eliminates torque fluctuations, improves drivability, and makes it possible to thin the air-fuel mixture.

An object of the present invention is to provide a new intake system for an engine that can improve fuel efficiency.

Therefore, the engine intake system of the present invention manually transmits the output of a temperature sensor that detects engine temperature to a control device that controls an on-off valve that is installed in a high-load intake passage and opens and closes when the load exceeds a set load. , by correcting and controlling the opening/closing valve in the closing direction according to the decrease in engine temperature using the output from the control device, so that according to the decrease in engine temperature,
Increasing the sharing ratio of the low-load intake passage, especially in the range from low to medium load and from medium to high load, increases the air flow velocity and improves swirl. It is characterized by strengthening fuel atomization and vaporization, improving combustion performance, improving drivability, and further improving fuel efficiency.

Hereinafter, the present invention will be explained in detail with reference to illustrated embodiments.

In Fig. 1, 1 is a cylinder, 2 is a cylinder head, 3 is a cylinder, 4 is a combustion chamber, 5 is an intake passage, 6 is a venturi portion formed at the upstream part of the intake passage 5, and 7 is a venturi. Main nozzle provided in section 6, 8 is venturi section 6
A throttle valve 11 provided downstream of the intake passage 5 connects the intake passage 5 to the low-load intake passage 12 in the vicinity of the combustion chamber 4.
A partition wall 1/j that partitions the high-load intake passage 13 into the rotation shaft 1 at the upstream end of the high-load intake passage 13
5 is fixed to an on-off valve for opening and closing the high-load intake passage 13; and 16 is an on-off valve that opens and closes the opening of the intake passage 5 to the combustion chamber 4 to open and close the low-load intake passage 12 and the high-load intake passage 13. An intake valve opens and closes, 17 is an exhaust passage, and 18 is an exhaust valve.

Further, 21 is an actuator that operates the on-off valve 14, 22 is an exhaust pressure sensor that detects the exhaust pressure of the exhaust passage 17, and 23 is a temperature sensor that protrudes into the quarter jacket 24 formed in the cylinder 1 and detects the cooling water temperature. ,2
Reference numeral 5 denotes a control device that receives outputs from the exhaust pressure sensor 22 and temperature sensor 23 and controls the actuator 21 as described later.

The actuator 21 includes a diaphragm device 27 and a solenoid valve 28. The diaphragm device divides the interior of the casing 31 into an atmospheric chamber 33 and a negative pressure chamber 34 by a diaphragm 32, and an actuating rod 35 having one end fixed to the diaphragm 32 penetrates the atmospheric chamber 33 and projects from the casing 31. A spring 36 is compressed in the negative pressure chamber 34,
The actuating rod 35 is moved in and out of the casing 31 according to the negative pressure in the negative pressure chamber 34. The tip of the operating rod 35 is connected to the rotating shaft 15 of the on-off valve 14 via a pin and a lever 39, so that the on-off valve 14 can be opened and closed by moving the operating rod 35 in and out. Further, the negative pressure chamber 34 of the diaphragm device 27 is communicated with the intake passage 5 downstream of the throttle valve 8 via a passage 41. A branch passage 45 having a tip opening 44 facing the valve body 43 of the electromagnetic valve 28 is branched from the middle of the passage 41 .

The electromagnetic valve field operates the valve body 43 in response to a signal from the control device 25 to control the degree of opening between the valve body 43 and the opening 44, thereby controlling the negative pressure in the negative pressure chamber 34. It has become. In addition, a throttle 46 is provided in the middle of the branch surface path 45 to stabilize the control of the negative pressure in the negative pressure chamber 34.

On the other hand, as shown in FIG. 2, the control device 25 includes an operational amplifier 51. A correction circuit 52 and an emitter follower circuit 53 are provided.

A signal from the exhaust pressure sensor -22 is input to the non-inverting input terminal of the arithmetic amplifier [1] 51, while a signal from the battery 55 whose cathode is grounded is input to the inverting input terminal of the arithmetic amplifier 51.
The anode of the amplifier 51 is connected through a resistor R+, and the output terminal of the operational amplifier 51 is connected through a feedback resistor L. Therefore, when the operational amplifier 51 receives a signal from the exhaust pressure sensor 22 whose level increases in accordance with the exhaust pressure as shown by the curved line in FIG.

A signal as shown by curve M in FIG. 4 is amplified and output.

The output signal shown by the curve M rises from the exhaust pressure PI, increases linearly as shown by the curve M+, and when the exhaust pressure reaches P2, becomes a value parallel to the horizontal axis as shown by the curve N. The above exhaust pressure P1, that is, the rising point P+ of the curve M is determined by the potential of the battery 55, the resistance le, and the ratio of the angle -, and the curve oil indicates the saturation region that is the power supply voltage of the semi-amplifier 51. It is something.

On the other hand, the correction circuit 52 is based on a function that is not shown, but...
1yu□Aka1. ．． 9, □...餉. Engineering, yes.

A coefficient N as shown in curve N in FIG. 5 is generated according to the temperature input from the sensor 23, and the arithmetic circuit multiplies the coefficient N by the signal M input from the arithmetic amplifier 52. The arithmetic processing is performed to create a signal, and the signal is output to the emitter follower circuit 53.

As shown in Fig. 5, the coefficient N generated by the function generator becomes zero when the temperature detected by the temperature sensor 23 is below o'c, and increases linearly between σ and 60°C. , becomes a constant value of 1 when the temperature exceeds 60'C. Therefore, the temperature detected by the temperature sensor 23 is, for example, 30
゛C, the coefficient N becomes 05, and the level of the signal ■ output from the correction circuit 52 is
This is half the level of the output signal M of 1.

On the other hand, the emitter follower circuit 53 includes a transistor 61 and a resistor 62, inputs the output of the correction circuit 52 to the transistor 610, and inputs the output of the correction circuit 52 to the transistor 610.
The power supply VCC is connected to the collector of the power source VCC, the resistor 62 is connected between the collector and the ground, and the resistor 62 is further connected to the collector. therefore,
The electromagnetic valve 28 operates according to its emitter potential which follows the base potential of the transistor 61. The higher the input level of the solenoid valve, the more the valve body 43 shown in FIG.
approach the opening 44 of the branch passage 45, and open the opening 44.
It is designed to work in a way that narrows down the area. therefore,
As the input to the electromagnetic valve 28 becomes higher, the negative pressure in the negative pressure chamber 34 of the diaphragm device 27 increases, and the diaphragm 32 is activated, causing the valve to retract, causing the opening/closing valve 1
4 is open.

The intake system of the engine configured as described above operates as follows.

Let us now assume that the engine temperature is high and the temperature detected by the temperature sensor 23 is 60°C or higher.

At this time, the function generator of the correction circuit 52 of the control device 25 generates a coefficient 1 based on the output of the temperature sensor 23, as shown in FIG. On the other hand, the arithmetic amplifier 51 of the control device 25 generates a signal M corresponding to the exhaust pressure as shown in FIG. 4 based on the output of the exhaust pressure sensor 22 corresponding to the load.
Create and output. The arithmetic circuit of the correction circuit 52 is as follows:
The output signal M of the operational amplifier 51 is multiplied by the coefficient 1, and the output signal M is directly output to the base of the transistor 610. Therefore, the solenoid valve A is driven by the above output signal M. Therefore, as shown in FIG. 4, in a low load state where the exhaust pressure is P1 or less, the output signal M becomes zero, so the valve body 43 of the solenoid valve 28 is opened at the opening 'f1.
4, the negative pressure chamber 34 of the diaphragm device 27 communicates with the atmosphere through the open opening 44, the negative pressure becomes small, and the actuating rod 35 is moved by the spring 36. The spring force protrudes and closes the on-off valve 14. Therefore, the air-fuel mixture is supplied to the combustion chamber 4 at high speed through only the low-load intake passage 12, generating a strong swirl, improving fuel atomization and vaporization, and improving combustion performance, drivability, and fuel efficiency. Get better. Then, the exhaust pressure becomes P in Figure 4.
In the case of a medium load condition of 1% to 2%, the curve M in Fig. 4
1, the level of No. 8 M1 increases as the exhaust pressure increases, and the valve body 43 of the solenoid valve 28 approaches the opening 44 in accordance with the exhaust pressure. Narrow down that opening play.

The negative pressure in the negative pressure chamber 34 of the diaphragm device 627 becomes larger as the degree of opening of the opening 44 becomes smaller, causing the actuating rod 35 to sink into the casing 31. Therefore, the on-off valve 14 is operated by the signal M1 to increase its opening as the exhaust pressure increases, and in addition to the low-load intake passage 12, the high-load intake passage 1
3 is also supplied to the combustion chamber 4. therefore,
In addition to good fuel atomization and vaporization, the intake resistance is small,
Filling efficiency and output performance are improved. Next, when the exhaust pressure is 12 or more as shown in FIG.
*J43 comes into close contact with the opening 44 and closes it. Therefore, the negative pressure in the negative pressure chamber 34 of the diaphragm device 27 becomes equal to the negative pressure in the intake passage 5, and the actuating rod 35 is retracted by the operation of the diaphragm 32 to fully open the on-off valve 14.

Therefore, this bulk □At the time of load, the intake passage for low load]
2 and the fully open high-load intake passage 134, the air-fuel mixture is supplied to the combustion chamber 4, thereby improving charging efficiency and improving output performance.

Next, it is assumed that the temperature detected by the temperature sensor 23 is between O'C and 60C in a state where the engine temperature is lower than in the above case and the fuel atomization and vaporization properties are poor.

At this time, the function generator of the correction circuit 52 of the control device 25 generates a coefficient N+ which is less than 1 and decreases linearly as the detected temperature decreases, as shown in FIG.

Then, the arithmetic circuit of the correction circuit 52 calculates the coefficient N+
By multiplying the signal shown by the curve M in FIG. Output to the base of. Therefore, the solenoid valve 28 is
By means of the signal □ which is lower level than the signal M when the aforementioned detected temperature is 60°C or more, the drive opening/closing valve □ is corrected and controlled in the closing direction according to the decrease in the engine temperature as described below. In other words, Figure 4, 0,
fo♀゛□yo 1, oh, eka 8.・1 step. I□,'1
:In the case of the I state, the above signal ■ is at zero level, so
As in the case where the detected temperature is 60°C or higher, the solenoid valve 28 is located at the normal position and the opening 44 is fully opened.
By protruding the operating rod 35 of the diaphragm device 27,
Close the on-off valve 14. Therefore, at this time, the air-fuel mixture is supplied to the combustion chamber 4 only through the low-load intake passage 12 at high speed.
A strong swirl is generated, improving fuel atomization and vaporization, improving combustion performance and driveability.

Improves fuel efficiency. Next, when the exhaust pressure is in a medium load state from P1 to P2 in Figure 4, the level of the signal Vl input to the solenoid valve field changes according to the rise in exhaust pressure, as shown by curve v1 in Figure 4. However, since the level of the signal M1 is lower than the level of the signal M1 mentioned above, the valve body of the solenoid valve is brought closer to the opening, and the opening 44 is lowered to the level of the above-mentioned detected temperature 60'C or higher. Narrow it down even more. Therefore, the negative pressure in the negative pressure chamber 34 of the diaphragm device 27 becomes greater than in the case described above, and the actuating rod 35 is recessed into the casing 31 more than in the case of 60° C. or more as described above. Therefore, the temperature detected by the temperature sensor 23 is 60% from o'c.
``If the temperature is less than 0, the opening degree of the on-off valve 14 will be smaller than when the detected temperature is 6°C or higher, and will also become smaller as the detected temperature decreases.
3 is throttled, the flow velocity of the air-fuel mixture passing through the low-load intake passage 12 is accelerated, the swirl is strengthened, and the fuel is atomized and the vaporization power becomes J:. Compensation is made for the deterioration of fuel atomization and vaporization due to a drop in engine temperature during runoff and medium load. Next, when the exhaust pressure is in a high load state of 12 or more as shown in FIG. lower than that of pigeons. For this reason,
The opening 44 of the valve body of the solenoid valve is narrowed by a certain amount, and the operating rod 35 of the diaphragm device 27 is immersed into the casing 31 by a certain amount by the operation of the diaphragm 32, and the opening/closing valve 1 is
4 is narrowed down to a certain opening degree. Therefore, even in a high load state where the exhaust pressure is P2% or more, if the temperature detected by the temperature sensor 23 is less than 60°C, the high load intake passage 13 is throttled by the on-off valve 14 as described above. As a result, the flow velocity of the air-fuel mixture passing through the low-load intake passage 12 is accelerated, the swirl is strengthened, and the atomization of the fuel is improved by lowering the engine temperature.
Compensation is made for the deterioration of vaporization.

Next, the engine temperature is extremely low and the temperature sensor 23
It is assumed that the detected temperature is 0°C or lower.

At this time, as shown in FIG. 43 is located in the normal position and the opening 44 is always open.
completely open. Therefore, the on-off valve 14 is always completely closed by the diaphragm device 27. therefore,
The flow velocity of the air-fuel mixture passing through the low-load intake passage 12 is increased, the swirl is strengthened, and the poor atomization and vaporization properties of the fuel due to the extremely low engine temperature are compensated for.

In this way, since the on-off valve 14 is corrected and controlled in the closing direction in accordance with the decrease in engine temperature in the medium to high load range, the fuel 1. Good atomization and vaporization of the material □・.

The flammability is improved! □.

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l ff1e * m9'J f u -' 7 ',
Is (') i# T iC response L-11iar) The valve closing is corrected and controlled in the closing direction, and the timing at which the valve starts to open according to the valve closing load does not change even if the engine temperature drops, but the opening and closing The load at which the valve starts to open may be increased in accordance with the decrease in engine temperature. Also,
In the above embodiment, the load is detected by exhaust pressure, but it may also be detected by venturi negative pressure, throttle opening, air flow sensor, etc. Further, in the above embodiment, the actuator is provided in an intake passage and is actuated using negative pressure, but it may be actuated using exhaust pressure. Further, the control device is not limited to the above embodiment, and various configurations are possible, including digital circuits, analog circuits, etc.
Regardless of mechanical device.

As is clear from the above description, the engine intake system of the present invention includes an on-off valve in the high-load intake passage that opens and closes when the load exceeds a set load, and also operates in response to the output of a temperature sensor that detects engine temperature. ': 1° Since it is equipped with a control device that corrects and controls the on-off valve in the closing direction according to a decrease in engine temperature, the high-load intake passage can be closed or throttled with the on-off valve when the engine is at low temperature.
By increasing the sharing ratio of the load intake passage, the air flow speed can be increased and the swirl can be strengthened, which can promote fuel atomization and vaporization, improving combustibility and improving drivability.
Furthermore, fuel efficiency can be improved.

[Brief explanation of drawings]

Fig. 1 is a sectional view of an embodiment of the present invention, Fig. 2 is a circuit diagram of a control device, Figs. 3 and 4 are graphs showing exhaust pressure-output characteristics, and Fig. 5 shows temperature-coefficient characteristics. This is a graph showing. 4... Combustion chamber, 12... Intake passage for low load, 13...
...Intake passage for high load, 14...Opening/closing valve, 23...
Temperature sensor, 25...control device.

Claims (1)

[Claims] (1) At least in the vicinity of the combustion chamber, an independent low-load intake passage and a high-load intake passage are provided, and the high-load intake passage is provided with an on-off valve that opens and closes when the load exceeds a set load. In an engine that supplies intake air from the low-load intake passage when under load, and from the low-load intake passage and high-load intake passage when under high load with a large amount of intake air, engine temperature detection is possible. 1. An intake system for an engine, comprising: a temperature sensor; and a control device which receives the output of the temperature sensor and corrects and controls the on-off valve in the closing direction in response to a decrease in engine temperature.