JP2752463B2 - Intake control device for internal combustion engine - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plurality of intake control valves disposed separately from intake valves of an internal combustion engine for each intake passage communicating with each cylinder.

[Conventional technology]

Conventionally, it has been considered to provide such an intake control valve for each intake passage to prevent a backflow of the internal combustion engine. That is, at the start of the intake stroke of the internal combustion engine,
Conceptual gas in the cylinder and exhaust passage flows back into the intake passage due to valve overlap, which reduces intake charge efficiency, and improves intake charge efficiency by preventing intake backflow using an intake control valve. Thus, the torque of the internal combustion engine is increased and the fuel efficiency is improved.

To switch the opening and closing of such an intake control valve,
An intake control valve is provided for each intake passage communicating with each cylinder, and the plurality of intake control valves are controlled to be opened and closed by independent actuators.

In this device, each intake control valve controls the opening / closing timing according to the operating state (rotational speed, load, etc.). However, when compared for 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 that engine torque, vibration, intake noise, and the like fluctuate.

Also, when the engine is accelerating or decelerating,
There is a problem that the air amount changes according to the opening and closing of the throttle valve, the mixture ratio changes, and engine vibration and eventually engine stall occur.

Accordingly, an object of the present invention is to control the intake control valve at an optimal closing timing based on the acceleration or deceleration state of the internal combustion engine to prevent the mixture ratio from fluctuating.

[Means for solving the problem]

In order to solve the above problems, an intake control device of the present invention is provided for each of a plurality of intake passages communicating with each cylinder of an internal combustion engine, and a plurality of intake control valves for opening and closing the intake passages. Opening / closing drive means for independently opening / closing the intake control valve; and a pressure regulating valve for regulating the pressure of intake air reaching each cylinder via the intake control valve by an opening degree of a valve body, wherein an acceleration state of the internal combustion engine is provided. Or, detecting means for detecting a deceleration state, and after detecting the acceleration state or the deceleration state by this detection means, by independently closing the plurality of intake control valves, it is possible to keep the mixing ratio substantially constant. Features.

〔The invention's effect〕

As described above, in the present invention, by controlling the closing timing of the intake control valve in accordance with the acceleration state or the deceleration state, the fuel mixture ratio can be made substantially constant, and engine vibration or engine stall can be prevented. There is an excellent effect.

〔Example〕

 Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows a system configuration of an engine on which the intake control device of the present embodiment is mounted.

In FIG. 1, the system includes a four-cylinder engine 1,
The engine 1 includes an intake control unit 3 disposed in an intake system 1a of the engine 1 and an electronic control unit (hereinafter simply referred to as ECU) 4 for controlling the intake control unit 3.

The engine 1 has four cylinders 5, 6, 7, 8 and each cylinder 5,
The intake valves 9, 10, 11, 12 which are opened / closed by the high-speed compatible cams are arranged in 6, 7, 8 and exhaust valves 13, 14, 15, 16 are also provided. The intake system 1a of the engine 1 has a throttle valve 40 as a pressure regulating valve.
The opening of the throttle valve 40 is drive-controlled by a throttle actuator 41.

Further, intake ports 17, 18, 19, and 20, which are branched from the intake system 1a and communicate with the cylinders 5, 6, 7, and 8, are provided. Intake ports 17, 18, 19, and 20 are respectively provided with intake control valves 21, 22, 23, and 24. These intake control valves 21, 22, 23, and 24 are respectively provided with actuators 25 as opening / closing drive means. , 26, 27, 28 are driven to open and close independently of each cylinder.

The engine 1 includes, as a detector, a crank sensor 29 that outputs a pulse signal when a piston (not shown) of each of the cylinders 5, 6, 7, 8 is located at the top dead center (TDC). A rotational speed sensor 30 for outputting a pulse signal, a means 31 for detecting torque or combustion for each cylinder (for example, an in-cylinder pressure sensor, a torque sensor, a knock sensor), and a means 32 for detecting an air amount for each cylinder (for example, an intake pipe pressure sensor) ), Load detecting means (for example, a throttle sensor and an accelerator sensor) for detecting a load state, noise / vibration detecting means for detecting noise or vibration, and emission detecting means for detecting an emission state.

The engine 1 has a control means 36 for controlling the injection amount and the injection timing by the injector, an ignition timing control means 37 for controlling the ignition timing, and a supercharging means for supercharging the intake air.
38, learning control means 39 for performing learning control according to the driving state,
An intake air heating means 42 for heating the intake air and a cooling water temperature adjusting means 43 for adjusting the temperature of the cooling water are provided.

The ECU 4 is configured as a logical operation circuit around the CPU 4A, ROM 4B, and RAM 4C, is connected to the input / output unit 4E via the common bus 4D, and performs input / output with the outside. The detection signal from each sensor and the signal from each control unit are input from the input / output unit 4E to the CPU 4A. On the other hand, the CPU 4A controls the actuators 25, 26, 27, 28 and the throttle actuator 4 via the input / output unit 4E.
1. Output control signals to the supercharging means 38 and the intake heating means 42.

 Next, a control method according to the present embodiment will be described.

Regarding the intake air for each cylinder, the input signal from the means 32 for detecting the air amount for each cylinder and the actuators 25, 26, 27, 2
The injection control means 36 is determined based on the valve opening / closing timing command signals of the intake control valves 21, 22, 23, 24 to 8 and based on the calculation result, the injection control means 36 determines the injection amount of the injector for each cylinder.

Next, the basic control of the valve opening timings of the intake control valves 21, 22, 23, and 24 is based on the input signal of the rotational speed sensor 30, and as shown in Table 1, the top dead center increases as the rotational speed increases. Driving means 25, 26, 27, 28 so that the amount of advance to the point is large
Is controlled by In Table 1, the valve opening timing indicates the advance amount with respect to the top dead center.

The basic control of the closing timing of the intake control valves 21, 22, 23, 24 is set as follows. That is,
The intake air amount is determined by multiplying the air density by the intake time.Conventionally, the adjustment of the air amount at a partial load was performed by changing the air density with a throttle valve while the intake time was constant. In order to reduce the pump loss, not only the air density but also the intake time was adjusted, so the valve closing times of the intake controls 21, 22, 23, and 24 depended on the load as shown in Table-2. Controlled.

In Table 2, the valve closing time indicates an advance amount with respect to the bottom dead center.

In the present invention, the relationship between the accelerator depression amount and the opening degree of the throttle valve 40 is conventionally proportional as shown in FIG. 2, but the α inclination is changed when the accelerator depression amount is small and large. Thus, high performance during deceleration can be secured.

That is, as shown in FIG. 3, when the accelerator at the time of deceleration is returned, the throttle valve 40 does not suddenly shift to the almost fully closed state, but stops at about 60% open. Therefore, in the past, the intake air amount sharply decreased, and the mixing ratio (hereinafter referred to as A / F)
However, by setting the opening degree of the throttle valve 40 as described above, the intake air amount does not suddenly pass, and the A / F state is almost combined with the A / F control described above. It can be close to constant.

In the present embodiment, the valve closing timing is different from the basic valve closing control described above.
It is determined by calculation with various correction terms according to the operating state. Since this correction term is provided for each cylinder, the amount of intake air of each cylinder is determined to be an optimum value according to the operating condition. The correction formula is shown below.

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

 TC = TCBSE + TTC + FTC + TRTC + BTC + NTC + NETC + TDC ………………………………………………………………………………………………………………………………………………………………………………………………… (1) FTC is the correction advance of combustion temperature. TRTC is the advance of acceleration slip (traction) control. BTC is the advance of intake brake control during deceleration. NTC is the correction advance of knock. NETC is the correction advance of equal air amount control. Angular amount TDC indicates the amount of advance of the actuator over time.

Next, based on the flowchart shown in FIG.
(Air / Fuel) control will be described.

In step 100, the pressure [Delta] P _n is a predetermined value [Delta] P in the engine
It determines whether _L or more, the pressure [Delta] P _n is determined to an acceleration state at step 110 equal to or greater than a predetermined value, the process proceeds to the acceleration control.

In step 120, the control valve opening timing (TOBSE), closing timing (TCBSE), opening degree (TS) of the throttle valve 40, and the like are read.

In step 130, the acceleration / deceleration correction advance amount basic value TTCBSE is determined based on, for example, the values shown in Table 3 below.

In step 140, as shown in Figure 6, with respect to the pressure [Delta] P _n, reads the correction coefficient K1.

Then, in step 150, the calculation of the acceleration correction advance amount TTC is obtained by TTC = K1 * TTCBSE based on the above-described basic value TTC BSE and the correction coefficient K1.

In step 160, the cylinder to be taken next is checked, and in step 170, the TTC obtained in step 150 is substituted by equation (1) to determine the closing timing. Based on this closing timing, the intake control in the cylinder is performed. Control the valve.

That is, in the acceleration state, the closing timing of the control valve is advanced as shown by the arrow as shown in FIG. 7 (b).

Then, as shown by the dashed line in FIG. 4 (c), the A / F shifts to the lean side due to the rapid increase in the amount of air, whereas as shown in FIG. 4 (d), A change in A / F can be eliminated by gradually increasing the amount of air.

Further, in step 180, the pressure ΔP _n is obtained, and in step 190
In comparing the pressure [Delta] P _n and a predetermined pressure [Delta] P _L, the pressure [Delta] P _n is greater than a predetermined pressure [Delta] P _L, the flow returns to step 140. On the other hand, if smaller pressure [Delta] P _n good predetermined pressure [Delta] P _L, completed at that time.

On the other hand, in step 100, the pressure ΔP _n
If it is smaller than _L, it is determined in step 210 that the vehicle is in a deceleration state, and the process proceeds to deceleration control.

Step 120 and step 230 are the same as those described above.
As in steps 120 and 130, the respective values are read.

In step 240, as shown in Figure 6, read the correction coefficient K2 for the pressure [Delta] P _n.

Then, in step 250, the deceleration correction advance angle TTC is calculated by using the basic value TTC BSE obtained in each of the above steps and the correction coefficient K2.
Is calculated by TTC = K2 * TTCBSE based on

In step 260, the cylinder to be taken next is checked, and step 2
At 70, the closing time is determined by substituting the TTC obtained at step 250 into the equation (1).

Then, the intake control valve in the cylinder is controlled based on the closing timing.

That is, in the deceleration state, the closing timing of the intake control valve is advanced as shown by the arrow as shown in FIG.

Therefore, conventionally, as shown by the dashed line in FIG.
While the A / F shifts to the rich side due to the rapid decrease in the amount of air, as shown in FIG. 3 (d), the A / F is gradually reduced as shown in FIG. 3 (c). As shown in (1), the change in A / F can be suppressed.

Therefore, since the closing timing of the intake control valve can be controlled for each intake cycle and each cylinder in this manner, very accurate and accurate A / F control becomes possible.

[Brief description of the drawings]

FIG. 1 is a system diagram showing the overall configuration of the apparatus of the present invention, and FIG.
FIGS. 3 and 4 are characteristic diagrams showing the relationship between the accelerator pedal depression amount and the throttle valve opening degree in this embodiment. FIGS. 3 and 4 show the accelerator pedal depression amount, the spelling valve opening degree during deceleration and acceleration.
A graph showing the A / F and the amount of air, and FIG. 5 shows the A / F of the above device.
Flowchart in the control, FIG. 6 is a characteristic diagram showing the relationship between the correction coefficient for the pressure [Delta] P _n, FIG. 7 (a), (b)
FIG. 4 is a diagram showing a closed profile of an intake control valve. 21, 22, 23, 24 ... intake control valve, 25, 26, 27, 28 ... actuator (opening / closing drive means), 40 ... throttle valve (pressure regulating valve).

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Hideki Obayashi 1-1-1, Showa-cho, Kariya-shi, Aichi, Japan Inside Denso Corporation (72) Inventor Hiroyuki Aota 1-1-1, Showa-cho, Kariya-shi, Aichi Japan Nihon Denso Co., Ltd. (72) Inventor Toshikazu Ina 14, Iwatani, Shimowasumi-machi, Nishio-shi, Aichi Japan Auto Parts Research Institute, Ltd.

Claims (1)

(57) [Claims] 1. A plurality of intake control valves provided for each of a plurality of intake passages communicating with each cylinder of an internal combustion engine to open and close the intake passages, and an opening and closing device for independently opening and closing the plurality of intake control valves. A driving means, and a pressure adjusting valve for adjusting the pressure of intake air reaching each cylinder via the intake control valve by an opening degree of a valve body, and detecting means for detecting an acceleration state or a deceleration state of the internal combustion engine. An intake control device for an internal combustion engine, characterized in that after detecting an acceleration state or a deceleration state by a detection means, each of the plurality of intake control valves is independently closed and controlled to keep the mixture ratio substantially constant.