JPH03117623A - Intake controller of internal combustion engine - Google Patents

Abstract

PURPOSE:To prevent generation of knocking in an engine by compensatingly controlling the close timing of intake control valves according to the number of generation of knocking. CONSTITUTION:Intake control valves 21 - 24 are arranged at every intake port which communicates with cylinders 5 - 8 of an engine 1 so as to open and close them. Actuators 25 - 28 openly and closely drive intake control valves 21 - 24 independently. In an electronic controller 4, closing timing of the intake control valves 21 - 24 is compensatingly controlled by the actuators 25 - 28 according to the number of generation of knocking secured by a knocking sensor 31. Generation of knocking at the cylinders 5 - 8 is surely controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a plurality of intake control valves that are separate from the intake valves of an internal combustion engine and are arranged for each intake passage that communicates with each cylinder.

[Conventional technology]

Conventionally, it has been considered to prevent backflow in an internal combustion engine by providing such an intake control valve for each intake passage. In other words, at the start of the intake stroke of an internal combustion engine, burned gas in the cylinders and exhaust passages flows back into the intake passage due to valve overlap, reducing the intake air filling efficiency. By preventing this, the intake air filling efficiency is improved and the torque of the internal combustion engine is increased.
The aim is to improve fuel efficiency.

As a device for switching the opening and closing of such an intake control valve, there is one in which an intake control valve is provided for each intake passage communicating with each cylinder, and each of the plurality of intake control valves is controlled to open and close by an independent actuator.

In this system, each intake control valve controls the opening/closing timing according to the operating condition (rotational speed, load, etc.), but when comparing each cylinder, the opening/closing timing is the same for all cylinders. If the amount of intake air varies due to the layout of the intake system, there is a problem in that the occurrence of engine knocks and the like will vary.

Therefore, it is an object of the present invention to prevent engine knock by controlling each intake control valve at an optimal closing timing in response to detection of knock.

[Means to solve the problem]

In order to solve the above problems, the intake control device of the present invention includes a plurality of intake control valves that are arranged for each of a plurality of intake passages communicating with each cylinder of an internal combustion engine and open and close the intake passages; an opening/closing drive means that independently opens and closes each intake control valve; a pressure regulating valve that adjusts the pressure of intake air reaching each cylinder via the intake control valve by the opening degree of a valve body; and a pressure regulating valve that detects knocking in each cylinder. A knock detection means is provided, and the closing timing of the intake control valve is corrected and controlled by the opening/closing drive means according to the number of knocks obtained by the knock detection means.

〔Effect of the invention〕

As described above, according to the present invention, each intake control valve is independently corrected and controlled to close the control valve, thereby reliably suppressing knock occurring in each cylinder.

〔Example〕

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

FIG. 1 shows the system configuration of an engine equipped with the intake control device of this embodiment.

In FIG. 1, this system includes a four-cylinder engine 11, 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, for example, four cylinders 5, 6, 7.8, and each cylinder 5, 6, 7.8 is provided with an intake valve 9, 10, 11, 12 that is opened and closed by a high-speed adaptive cam. Also, exhaust valves 13, 14, 15 .
16 are also provided.

A throttle valve 40 as a pressure regulating valve is disposed in the intake system 1a of the engine 1, and the opening degree of the throttle valve 40 is drive-controlled by a throttle actuator 41.

Further, intake ports 17, 18, 19° 20 are arranged which branch from the intake system 1a and communicate with each cylinder 5, 6° 7,8. Intake boat 17.1B.

19.20, intake control valves 21, 22, 23.2, respectively.
4 are arranged, and these intake control valves 21°, 22, 23 .
24 are actuators 25 each serving as opening/closing driving means.
, 26, 27, and 28, each cylinder is independently driven to open and close.

The engine 1 includes a crank angle sensor 29 as a detector that outputs a pulse signal when the piston (not shown) of each cylinder 5, 67.8 reaches the top dead center (TDC). A rotation speed sensor 30 that outputs a signal, a means 31 for detecting torque or combustion for each cylinder (for example, a cylinder pressure sensor, a torque sensor, a knock sensor), and a means 32 for detecting the air amount for each cylinder (for example, an intake pipe pressure sensor). , load detection means (
For example, a throttle sensor, an accelerator sensor), noise/vibration detection means 34 for detecting noise or vibration, and emission detection means 35 for detecting the state of emissions.

The engine 1 also includes a control means 36 for controlling and injecting the amount and timing of injection by the injector, an ignition timing control means 37 for controlling the ignition timing, a supercharging means 38 for supercharging intake air, and learning according to the operating state. A learning control means 39 that performs control, an intake air heating means 42 that heats intake air, and a cooling water temperature adjustment means 43 that adjusts the temperature of cooling water are provided.

ECU4 is CPU4A, ROM4B, RAI14C
It is configured as a logic operation circuit centered on the Columbus 4D
It is connected to the input/output section 4 through the input/output section, and performs input/output with the remote section. Detection signals from each sensor and signals from each control means are input to the input/output unit 4E (PUjA. On the other hand,
The CPU 4A outputs the actuators 25, 2E27.28, and the throttle actuator 4I via the output section 4E.
A control signal is output to the S% supply means 38 and the intake air heating means 42.

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

Regarding the intake air amount for each cylinder, it is the empty space for each cylinder.

Input signals from the means 32 for detecting the quantity and the intake control valves 21, 22, 2 to the actuators 25, 26, 27, 28
3.24, and 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, and 24 is performed based on the human power signal of the rotation speed sensor 30, as shown in Table 1, as the rotation speed increases. The driving means 2
5, 26, 27, and 28. In Table 1, the valve opening timing indicates the amount of advance relative to top dead center.

The basic control of valve timing is set as follows. In other words, the amount of intake air is determined by multiplying the air density by the intake time. Conventionally, the air amount could be adjusted at partial load by keeping the intake time constant and changing the air density using the throttle valve. In the embodiment, in order to reduce pump loss, not only the air density but also the intake time are adjusted, so the intake control valves 21, 22, 2
The valve opening time of 3°24 is 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 depression of the accelerator at this time is set as shown in FIG. In Table 2, the valve closing time indicates the amount of advance (CA) with respect to the bottom dead center.

Further, in this embodiment, the valve closing timing is determined by calculating the basic valve closing control with various correction terms depending on the operating state. Since this correction term is provided for each cylinder, the intake air amount for each cylinder is determined to be the optimum value depending on the operating situation.

Here, equation (1) shows an example of calculation of the valve closing timing.

TC-TCBSE+TTC+FTC+TRTC+BTC
+NTC+NETC+TDC...(1) In formula (1), TC is the advance amount of valve closing timing TCBSE is the basic valve closing advance amount TTC shown in Table-2 is the A/F correction advance angle during transition. FTC is the amount of correction advance for combustion temperature TRTC is the amount of advance for acceleration slip (traction) control BTC is the amount of advance for intake brake control during deceleration NTC is the amount of advance for correction during knock NETC is the correction for equal air amount control The advance angle amount TDC indicates the advance angle amount for correcting changes over time of the actuator.

In this correction control, in this embodiment, knock control at full load will be explained with reference to the flowchart of FIG. 2.

In step 100, the opening timing of the intake control valves 21 to 24 (
TOBSE) and 2t11 (TcBsE) when closed. In step 110, the knock correction values NTC (41) to (#4) of each cylinder at the end of operation are read, and based on these read values, in step 120, the closing timing corresponding to each cylinder #1 to #4 is determined. Find each actuator 2
5 to 28, signals for driving the intake control valves 21 to 24 are sent.

As a result, the closing timing control of the intake control valve at the end of operation is initialized.

Next, in step 130, a counter N that counts the number of times that knocking has occurred is initialized.

In steps 140 and 150, a knock signal is detected and a knock determination is made for each cylinder.

In step 160, step 140 and step 1
The number of consecutive knocks is measured in response to the 50 knock signals. In step 170, depending on the value of the number of consecutive knocks N,
For example, ΔN determined based on Table-39 Table 4 below.
Read TC.

Table 3 shows the case of a naturally aspirated engine, and Table 4 shows the case of a turbo engine.

Table-3 Table-4 In step 180, ΔN obtained in step 170 above is
A knock has occurred on the TC. For example, it is added to cylinder #1 and cylinder #4, and the closing timing of the control valves 21 to 24 is determined based on the above-mentioned equation (1).

On the other hand, in the cylinder in which no knock occurred in step 140 and step 150, step 190
Measure the time Δm during which no knock occurs. If this time Δt is 1 second or more, in step 200, the correction advance amount of the corresponding cylinder in which no knock has occurred is determined by IC.
A is subtraction.

Thereafter, the process returns to step 190, and if the time ΔL is 1 second or more, subtraction is performed in the same manner.

Further, in step 190, if the time Δt is less than 1 second, the process moves to step 210, and then moves to step 160,
Continue to control.

As a result, when the engine speed is 160 Orpm and knock occurs in cylinder #1 and cylinder #4, the closing timing of the intake control valves 21 and 24 is retarded as shown by the broken line in FIG. , it is possible to suppress the occurrence of knocking.

Further, if knocking occurs when the engine speed is 500 rpm, the closing timing of the intake control valve shown by the broken line in FIG. 4 is advanced to suppress the occurrence of knocking.

Next, learning correction for determining the control valve closing timing at which the torque always becomes maximum will be explained.

The present invention uses the pressure in the space between the intake valve and the control valve as a method for measuring the torque of each cylinder.

Figures 5 (a) and (b) show that the engine speed is 1200.
These are the above pressure waveforms measured with RPA, with and without control valve control, respectively. When controlled, the pressure after the control valve closes largely deviates to positive pressure. The peak of this positive pressure is detected by a pressure sensor for each cylinder. If measured every time, a relationship between the positive pressure peak and the torque improvement rate as shown in Fig. 6 can be obtained, and from this relationship, it can be seen that learning correction should be performed so that this peak becomes higher.

Next, the learning correction described above will be explained based on the flowchart shown in FIG.

In step 300, the correction term GC is advanced by ΔGC(CA), and in step 310, the peak pressure PRI is measured.

In step 320, the peak pressure value PR,, -1 before the advance angle is
If it is larger than that, step 330
The process proceeds to step 300, where a knock determination is made, and if no knock has occurred, the process returns to step 300 and the angle is further advanced by ΔGC. Further, in step 330, if a knock is detected, Gc is returned to its original value and the process is completed.

On the other hand, if in step 320 the peak pressure value PR after the advance angle becomes lower than the peak pressure value PR before the advance angle, the process moves to step 350.

In step 350, ΔGC is subtracted in the direction of retarding the correction term GC. Thereafter, the peak pressure is measured in step 360, and compared in step 370. If the peak pressure value PR is high, the process proceeds to step 380, and if it is low, the process proceeds to step 400, and the process is completed. step 380
determines if there is a knock, and if there is no knock, step 350
Return to

If there is a knock, the process proceeds to step 390, where the value before the knock is stored in the RAM as GC, and the process is completed.

In other words, by performing the above control, the closing timing of the control valve can be controlled in a range close to the maximum value of the positive pressure peak value, so as shown in FIG. 6, it is possible to improve the torque.

Figure 8 shows that when the above control is performed in the low rotation range (
That is, the control valve cass profile of the control of ΔGC is shown.

In the above embodiment, the torque of each cylinder is estimated at the peak of positive pressure, but this may be done using cylinder pressure, rotational fluctuations, or the output of a torque sensor.

[Brief explanation of drawings]

FIG. 1 is a system diagram showing the overall configuration of an embodiment of the present invention;
Fig. 2 is a flowchart showing the knock control of the present invention, Fig. 3 is a drawing showing the opening/closing profile of the intake control valve when the engine is running at low speed, and Fig. 4 is a drawing showing the opening/closing profile of the intake control valve when the engine is running at high speed. , Fig. 5 is a graph showing the relationship between pressure and crank angle, Fig. 6 is a graph showing the relationship between torque improvement rate and pressure peak value, and Fig. 7 shows the control of the intake control valve according to the positive pressure peak value. The flowchart shown in FIG. 8 is a diagram showing the cam profile of the intake control valve when the engine is running at low speed. 4... Electronic control device, 21-24... Intake control valve. 25-28...actiniator (opening/closing drive means). 40...Throttle valve (pressure adjustment valve).

Claims (1)

[Scope of Claims] A plurality of intake control valves that are arranged for each of a plurality of intake passages communicating with each cylinder of an internal combustion engine and open and close the intake passages, and a plurality of intake control valves that are independently driven to open and close. The apparatus includes an opening/closing drive means, a pressure regulating valve that adjusts the pressure of intake air reaching each cylinder via the intake control valve by the opening degree of a valve body, and a knock detection means that detects knock in each cylinder, An intake control device for an internal combustion engine, characterized in that the closing timing of the intake control valve is corrected and controlled by the opening/closing drive means in accordance with the number of knocks obtained by the means.