JPH04179824A - Suction control apparatus for internal combustion engine - Google Patents

Abstract

PURPOSE:To prevent return flow of a burned gas into an intake port during an overlap time period, by opening or closing an intake control valve during closure of an intake valve. CONSTITUTION:Intake control valves 21 to 24 are disposed in intake ports 17 to 20 corresponding, in the ratio of 1:1, to air cylinders 5 to 8, respectively to open and close the intake ports 17 top 20. Further, actuators 25 to 28 are provided correspondingly to the intake control valves 21 to 24 to drive the intake control valves 21 to 24. An ECU 4 opens or closes the intake control valves 21 to 24, during opening periods of intake valves 9 to 12, in accordance with the operational states, thereby controlling the intake stroke periods of the air cylinders 5 to 8. The ECU 4 controls the actuators 25 to 28 so as to open and close the intake control valves 21 to 24 at least once during closure periods of the intake valves 9 to 12. This permits the pressure of the intake ports 17 to 20 to be returned from negative pressure to a level near to that of atmospheric pressure, so that it is possible to prevent return low of a combusted gas to the intake ports 17 to 20 during an overlap time period.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an intake control device for an internal combustion engine that includes an intake control valve that adjusts an air intake period.

[Conventional technology]

Conventionally, as shown in Fig. 9, a system has been proposed in which the intake control valve is controlled to open and close depending on the load condition of the internal combustion engine during the period when the intake valve is open, thereby improving the output torque characteristics and fuel efficiency of the internal combustion engine. (For example, JP-A-63
-263220).

[8s to be Solved by the Invention] However, in the above-mentioned system, in the overlap period when both the intake valve and the exhaust valve are open, as shown in FIG. 9, the pressure at the intake port between the intake valve and the intake control valve is There is negative pressure. Therefore, during the overlap period, burnt gas in the exhaust pipe flows back into the intake port, making the next combustion unstable, causing torque fluctuations, and deteriorating drivability.

In view of the above problems, the present invention aims to stabilize combustion and improve drivability by preventing burned gas from flowing back into the intake port during the overlap period.

[Means to solve the problem]

Above lI! As a means for solving the problem, the present invention provides an operating state detection means for detecting the operating state of an internal combustion engine, and a means for detecting an operating state of an internal combustion engine, which is disposed at each intake port in one-to-one correspondence with each cylinder of the internal combustion engine,
An intake control valve that opens and closes the intake port, an actuator that is provided corresponding to each intake control valve and that drives the intake control valve, a detection means that detects the open/closed state of the intake valve of each cylinder, and the intake valve. control means for controlling the intake stroke period of each cylinder by opening and closing the intake control valve based on the operating state during the open period of the intake valve; and a control means for opening and closing the intake control valve at least once during the intake valve closing period. The present invention proposes an intake air control device for an internal combustion engine, characterized by comprising a sub-control means for controlling the actuator.

[Effect]

As a result, when the intake valve of each cylinder is open, the intake control valve corresponding to each cylinder is driven to open or close by the actuator based on the operating state, and the intake stroke period of each cylinder is controlled. Even when the intake valve is closed, the intake control valve is driven to open and close.

At this time, the pressure in the intake port returns from negative pressure to near atmospheric pressure, and when the intake valve and exhaust valve 7 open overlap, the burned gas in the exhaust pipe does not flow back to the intake port.

〔Effect of the invention〕

According to the present invention, by opening and closing the intake control valve while the intake valve is closed, the pressure at the intake port at the time of overlap becomes a value close to atmospheric pressure, so that the burned gas in the exhaust pipe cannot flow back to the intake port. combustion becomes stable. Therefore, there is an excellent effect that torque fluctuation is suppressed and drivability is improved.

〔Example〕

Hereinafter, the present invention will be described in detail based on the drawings.

FIG. 1 shows the configuration of an engine system in which the intake air control device of this embodiment is installed.

In FIG. 1, this system includes a four-cylinder engine 1, an intake control unit 3 disposed in an intake system 1a of the engine 1, and an electronic control unit (hereinafter simply ECU) that controls these.
4).

The engine 1 includes four cylinders 5, 6, 7.8, and each cylinder 5.6, 7.9 is provided with an intake valve 9, 10, 11.12 that is opened and closed by a high-speed adaptive cam. ,
Also provided are exhaust valves 13.14, 15.16. A throttle valve 40 as a pressure regulating valve is disposed in the intake system 1a of the engine 1, and the throttle valve 40 is connected to a throttle actuator 41.
The opening degree is drive controlled by. Further, an exhaust pipe 1b is connected to each of the exhaust valves 13 to 16.

Further, intake ports 17.1B and 19.degree. 20 are provided which branch from the intake system 1a and communicate with the respective cylinders 5, 6.degree. 7.8. Intake port 17.1B.

19.20, intake control valves 21, 22.23.3, respectively.
4 are arranged, and these intake control valves 21, 22, 23 .
34 are actuators 25 each serving as an opening/closing drive means.
, 26, 27, and 28, each cylinder is independently driven to open and close. Further, 17a, 18a, 19a, and 20a are upstream portions of the intake ports 17.1B and 19.20. This upstream part 1
Injectors 44, 45, 46, and 47 for injecting fuel are arranged at 7a, 18a, 19a, and 20a.

The engine 1 has a detector for each cylinder 5, 6, 7, 8.
A crank angle sensor 29 outputs a pulse signal when a piston (not shown) is located at top dead center (TDC), a rotation speed sensor 30 outputs a pulse signal at every predetermined crank angle, and detects torque or combustion for each cylinder. Means 3
1 (for example, cylinder pressure sensor, torque sensor, knock sensor), means 32 for detecting the air amount for each cylinder (for example, intake pipe pressure sensor), and load detection means 33 for detecting the load state.
(for example, a throttle sensor, an accelerator sensor), a noise/vibration detection means 34 for detecting noise or vibration, and an emission detection means 35 for detecting the state of emissions.

The engine 1 also includes a control means 36 for controlling and injecting the injection amount and timing by the injectors 44 to 48, an ignition timing control means 37 for controlling the ignition timing, a supercharging means 38 for supercharging the intake air, and a supercharging means 38 for supercharging the intake air. A learning control means 39 for performing learning control, an intake air heating means 42 for heating intake air, and a cooling water temperature adjusting means 43 for adjusting the temperature of cooling water are provided.

The ECU 4 is configured as a logic operation circuit mainly including a CPU 4A, a ROM 4B, and a RAM 4C, and is connected to an input/output section 4E via a common bus 4D to perform input/output with the outside.

Detection signals from each sensor and signals from each control means are input to the CPU 4A from the input/output section 4E. On the other hand, the CPU
4A is connected to the actuator 25, via the input/output section 4E.
26°27.2B, a control signal is output to the throttle actuator 41, supercharging means 38, and intake air heating means 42.

Further, the ECU 4 detects the opening/closing periods of the intake pulps 9 to 12 of each cylinder 5 to 8 based on the signals from the crank angle sensor 29 and rotational speed sensor 30 described above.

In addition, the intake control valves 21 to 24, as shown in FIG.
A butterfly-type circular valve plate 50 is provided in each of the intake ports 17 to 20, and this valve plate 50 is rotated to open and close by a support shaft 51. As shown in FIG. 4, the circular valve plate 50 has a structure in which it swings without contact with the walls of the intake ports 17 and 18 with a very narrow clearance. The support shaft 51 is supported by each of the intake ports 17 to 20 by bearings, and its end portion is connected to a lower driving portion 52.

FIG. 3 is a sectional view taken along the line AA in FIG. 2.

A magnet member 54 is fitted on the circular outer periphery of the support shaft 51 extending into the casing 53 of the drive unit 52, and magnetic poles are formed in the magnet member 54 so as to have different polarities symmetrically in the circumferential direction. . Further, a magnet member 5 is provided on the inner wall of the casing 53.
A pair of electromagnetic coils 55, 56 and a pair of permanent magnets 57, 58 facing each other are arranged.

FIG. 5 shows the control circuit for the electromagnetic coils 55 and 56. When the electromagnetic coils 55 and 56 are energized to the positive side, ! The magnetic member 54 swings to a position determined by the magnetic poles formed by the magnetic coils 55, 56 and the magnetic poles formed by the permanent magnets 57, 58, and the circular valve body 50 is moved as shown by the dashed line in FIG. Swings to the fully open position. Further, when the electromagnetic coils 55, 56 are energized to the negative side, the magnet member 54 rotates 90'', and the circular valve plate 50 swings to the fully closed position shown by the solid line in FIG. 4.

Furthermore, switch 59 in FIG. 5 is turned OFF! When the magnetic coils 55,56 are de-energized, the magnetic member 54 is held only by the magnetic poles of the permanent magnets 57,58, and the circular valve plate 50 swings to the half-open position shown in broken lines in FIG.

Next, the control method of this embodiment will be explained.

Regarding the amount of intake air for each cylinder, input signals from means 32 for detecting the amount of air for each cylinder and actuators 25, 2 are used.
Intake control valves 21.22, 23.24 to 6, 27.28
The injection control means 36 determines the injection amount of the injector for each cylinder based on the calculation result.

Next, basic control of the opening timing of the intake control valves 21, 22, 23, 24 when the intake valves 9 to 12 are open is based on the input signal of the rotation speed sensor 30.
As shown in Table 1, the actuator 25,26
．． 27.28. In Table 1, the valve opening timing indicates the amount of advance relative to top dead center.

Further, basic control of the closing timing of the intake control valves 21, 22, 23, and 24 is set as follows. In other words, the intake air amount is determined by multiplying the air density by the intake timing, and in this example, in order to reduce pump loss,
Since not only the air density is adjusted by the throttle valve 40, but also the intake time is adjusted, the intake control valve 2
The valve closing times of 1, 22, 23, and 24 are controlled according to the load as shown in Table 2. The relationship between the opening degree of the throttle valve 40 and the amount of accelerator depression at this time is set as shown in FIG.

In Table 2, the valve closing time indicates the amount of advance relative to the bottom dead center.

Furthermore, in this embodiment, in addition to the basic control of opening and closing the intake control valves 21 to 24 when the intake valves 9 to 12 are opened,
Even when intake valves 9-12 are closed, the intake control valves 2-1-
24 to open and close the intake control valve twice within one cycle of the engine.

Figure 7 shows the opening/closing timing of the intake control valve 21, intake valve 9, and exhaust valve 13, and the intake port 17.
3 is a timing chart showing pressure changes in the upstream portion 17a of FIG.

As mentioned above, when each intake control valve 21-28 is closed during the intake stroke of each cylinder 5-8, each intake control valve 21-2
8 and each cylinder 5 to 8 are filled with air. At this time, the piston is still descending, so the filled air expands adiabatically, so the upstream part 1
As shown in FIG. 7, the pressure at 7a decreases from atmospheric pressure to negative pressure and reaches its minimum value at the bottom dead center of the piston. Thereafter, as the piston rises, the pressure returns to the atmosphere side, and when the intake valve 9 is closed, the pressure in the upstream portion 17a is maintained at negative pressure.

Next, after the intake valve 9 is closed, the intake control valve 21 is opened again. Then, air suddenly flows into the upstream part 17a from the upstream side of the intake port 17, and the air suddenly flows into the upstream part 17a.
The pressure rises rapidly, causing pressure fluctuations near atmospheric pressure.

When the intake control valve 21 is closed again after a predetermined period of time has elapsed, the above-described pressure fluctuations subside and the pressure in the upstream section 17a is maintained at a value near atmospheric pressure.

After that, the exhaust valve 13 is opened and the control means 3
6, fuel is supplied from the injector 44 to the intake port 17.
is injected into the upstream portion 17a of. When the intake valve 13 is opened, the basic control of opening the intake control valve 21 described above is performed. This completes the control of one cycle of the engine.

Further, the other intake control valves 22 to 24 are also controlled to open and close twice in one engine cycle at similar timings.

As described above, in this embodiment, the injectors 44 to 47
Therefore, each intake port 17 at the fuel injection timing
The pressure in the upstream portions 17a to 20a of 20 to 20 has a stable value near atmospheric pressure. Therefore, the injection pressure of the fuel injected from the injectors 44 to 47 is stabilized. I mean,
The injection pressure is determined by the difference between the fuel pressure within the injector and the pressure at the upstream portions 17a to 20a where fuel is injected,
The fuel pressure is kept constant by the fuel pump and regulator, and the pressure in the upstream parts 17a to 20a is also kept constant near atmospheric pressure at the injection timing, so the injection pressure is stabilized at a constant value.

Therefore, it is possible to prevent fluctuations in the amount of injected fuel determined by the injection pressure and injection time, suppress air-fuel ratio fluctuations, and prevent torque fluctuations.

Further, since the pressure in the upstream portions 17a to 20a when both the intake valve and the exhaust valve are opened is approximately atmospheric pressure, the burned gas in the exhaust pipe lb does not flow back to the intake ports 17 to 20.

As another example, as shown in FIG. 8, when the intake valves 9 to 12 are closed, when controlling the opening and closing of the intake control valves 21 to 24, the intake control valves are not fully opened but only half open (similar to Good too.

When the intake control valves 21 to 24 are half-opened in FIG. 8, air flows into the upstream parts 17a to 20a from upstream of the intake ports 17 to 20, so the pressure in the upstream parts 17a to 20a increases, causing pressure fluctuations near atmospheric pressure. wake up When the intake control valves 21 to 24 are closed again after a predetermined period of time has elapsed, the pressure in the upstream portions 17a to 20a stabilizes at a value near atmospheric pressure. After that, fuel is injected from the injectors 44 to 47.

When the intake control valves 21 to 24 are set half open instead of fully open, there is no need to energize the electromagnetic coils 55 and 56 as described above, so energy consumption is reduced.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of the intake control device of the present invention, FIGS. 2 and 3 are sectional views of the intake control valve, FIG. 4 is an explanatory diagram explaining the operation of the intake control valve, and FIG. The figure is a drive circuit diagram of the intake control valve, Figure 6 is a characteristic diagram of the throttle valve, and Figure 7 is a diagram of the throttle valve characteristics.
8 and 8 are time charts showing the operation of the intake control valve in this embodiment, and FIG. 9 is a time chart showing the operation of the conventional intake control valve. 4...ECU, 25.26.27.28...Actuator, 21,22,23.34...Intake control valve. Representative Patent Attorney Takashi Okabe (and 1 other person) Figure 2, 3, and 4 completed? lLl Soto/i Fig. 6 Fig. 5 Fig. 7 Large de 5: Enclosed shot

Claims (2)

[Claims] (1) An operating state detection means for detecting the operating state of the internal combustion engine, an intake control valve that is disposed at each intake port in one-to-one correspondence with each cylinder of the internal combustion engine and that opens and closes this intake port, and this intake control valve. an actuator that is provided corresponding to each valve and drives the intake control valve; a detection means that detects an open/closed state of the intake valve of each cylinder; A control means for controlling the intake stroke period of each cylinder by opening and closing the valve, and a sub-control means for controlling the actuator so as to open and close the intake control valve at least once during the intake valve closing period. An intake control device for an internal combustion engine, characterized by: (2) The intake control device for an internal combustion engine according to claim 1, wherein the sub-control means controls the actuator to half-open and then fully close the intake control valve during the intake valve closing period. .