JPH03237237A - Output controller of internal combustion engine - Google Patents

Abstract

PURPOSE:To properly control output torque by interposing a second opening/ closing valve in parallel to a first opening/closing valve of each cylinder, decreasing a pumping loss with a simple structure, and controlling the second valve at every one combustion stroke based on required output torque of an engine. CONSTITUTION:When a piston is lowered, air is taken into a combustion chamber B by opening an intake valve A. An intake passage C which communicates with the intake valve A of each cylinder is opened and closed by a first opening/closing valve D. A communication passage E is communicated with the intake passage C at the downstream of the first opening/closing valve D, and the communication passage E is opened and closed by a second opening/closing valve F. The valve F is openly and closely driven by a driving means G. Required output torque of an engine is detected by a means H. The second opening/closing valve F is drivingly controlled at every one combustion stroke via the driving means G by a control means I based on the detected output torque. The pumping loss is decreased with a simple structure, and the output torque at every cylinder is controlled properly.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an output control system for an internal combustion engine that controls the output by controlling the intake air flow rate.

<Prior Art> Conventionally, the output torque of an engine is controlled by controlling the opening and closing of a throttle valve linked to an accelerator pedal to change the intake negative pressure downstream of the throttle valve. By the way, since the intake negative pressure is a temporary delay system with a time constant determined mainly by the intake passage volume with respect to the opening and closing of the throttle valve, it is difficult to control the output torque for each combustion stroke.

In addition, as shown in Figure 2 of S, A, E, Paper 880388, a rotary valve is installed in the intake passage upstream of the intake valve, and this rotary valve is opened and closed in synchronization with the opening and closing of the intake valve. ing. When the intake valve and the rotary valve open overlap, air is sucked into the combustion chamber by the downward movement of the piston. Here, by using the rotary valve, the air pressure downstream of the rotary valve is brought to approximately atmospheric pressure at the initial stage of opening of the intake valve, thereby reducing the pumping loss. At this time, since the volume of the intake passage downstream of the rotary valve is small, an amount of air approximately proportional to the intake air flow rate is introduced into the combustion chamber when the rotary valve and the intake valve overlap and open.

Furthermore, when the volume of the intake passage between the rotary valve and the intake valve is relatively large, a throttle valve is provided in the intake passage upstream of the rotary valve, although the effect of reducing pumping loss is reduced (S, A).

E, see Figure 9 of paper 88038B). By throttling the air with a throttle valve and lowering the pressure in the intake passage below atmospheric pressure in advance, the pressure in the combustion chamber when the piston is at bottom dead center is reduced to -55% during idling, for example.
It is possible to set it to 0m+++ Hg.

Furthermore, Japanese Patent Application Laid-Open No. 148932/1984 is a method that includes a rotary valve upstream of the intake valve.

<Problems to be Solved by the Invention> However, in such conventional examples, since a rotary valve is provided in series with the intake valve, a plurality of gears must be combined in order to change the rotational phase of the rotary valve. Since the pump has a complicated structure, the friction loss is large and the overall effect of reducing pumping loss is reduced. Further, due to the complicated structure, it is difficult to control the intake air flow rate for each cylinder.

The present invention has been developed in view of these circumstances, and has a simple configuration that greatly reduces pumping loss while controlling the intake air flow rate for each cylinder with high precision to control the output torque for each combustion stroke. The purpose of the present invention is to provide an output control device for an internal combustion engine that is capable of controlling the output of an internal combustion engine.

<Means for Solving the Problems> For this reason, the present invention, as shown in FIG. Intake valve A of each cylinder
A first on-off valve that opens and closes the intake passage C that communicates with the intake passage C, a communication passage E that communicates with at least the intake passage C downstream of each first on-off valve, and a second on-off valve F that opens and closes the communication passage E, respectively. , a drive means G for driving these second on-off valves, an output detection means H for detecting the required output torque of the engine, and a drive means G based on the detection result of the output torque detection means H.
A control means f for driving and controlling each of the second on-off valves F for each combustion stroke is provided.

<Operation> In this way, by interposing the second on-off valve in parallel with the first on-off valve provided for each cylinder, the intake air flow rate can be adjusted for each cylinder while significantly reducing pumping loss with a simple configuration. was able to be controlled. Furthermore, by controlling the second on-off valve for each combustion stroke based on the detected required output torque, the output torque of each cylinder can be optimally controlled.

<Example> An example of the present invention will be described below based on Figures v42 to 12. In the embodiment, a four-cylinder internal combustion engine will be described as an example.

In FIGS. 2 and 3, a butterfly-type throttle valve 2 is connected in series with an intake valve 3 as a first opening/closing valve that is linked to the accelerator pedal's sliding action in an intake passage 1 formed independently for each cylinder. The series il! are arranged in and interposed respectively to bypass each throttle valve 2! A bypass passage 4 is formed as a passage. A second on-off valve 5 is interposed in each of the bypass passages 4, and the second on-off valve 5 is driven to open and close by an electromagnetic actuator 5A serving as a driving means. A control signal is manually applied to the actuator 5A from a m control device 6 as a control means. Here, the volume of the intake passage 1 from the throttle valve 2 to the intake valve 3 is set to approximately X of the maximum volume of the combustion chamber (combustion chamber volume when the piston is at the bottom dead center).

The control device W6 receives a reference signal (every 180° in crank angle) and a positive signal (for example, every 1° in crank angle) from the crank angle sensor 7, and a spark plug 80 embedded in the washer of each cylinder. A cylinder pressure detection signal from a cylinder pressure sensor (not shown) as an output torque detection means,
is entered.

The control device 6 operates according to the flowcharts shown in FIGS. 4 to 7, and outputs a control signal to the actuator 5A to control the opening and closing of the second on-off valve 5.

Note that 9 is a fuel injection valve.

Next, the operation will be explained according to the flowcharts shown in FIGS. 4 to 7. Here, the routine shown in the flowcharts of FIGS. 4 and 7 is as shown in FIG.
This is executed by an interrupt routine every time a reference signal is input from the job (referred to as a reference job in FIG. 8). Further, the routine shown in the flowchart in Fig. 5 is executed by an interrupt routine when the set crank angle (near the top dead center of #1 cylinder), which will be described later, is reached as shown in Fig. 8. (referred to as a crank job).

The routine shown in the flowchart of FIG. 6 is always executed twice when the interrupt routine is not executed.

First, the flowchart shown in FIG. 4 will be explained.

At Sl, the set crank angle for executing the routine shown in the flowchart of FIG. 5 is set. As shown in FIG. 9, this set crank angle is set at a position near the top dead center immediately before the mixture starts to burn (ignition starts) in the compression stroke of the #l cylinder.

In S2, it is determined from the reference signal whether or not it is the #1 cylinder. If YES, the process proceeds to S3; if NO, the process proceeds to S6.

In S3, 1 is added to the variable counter value and the process proceeds to S4.

In S4, it is determined whether or not the added variable counter value has reached 3. If YES, the process proceeds to S5, and if NO, the process proceeds to S6.

In S5, the variable counter value is initialized to O.

Therefore, the variable counter values are 0, 1.2, 30.1
．． 2 is repeated, and the value is changed when the reference signal is manually operated when the #l cylinder is in the compression stroke.

In S6, the combustion chamber pressure read in the routine described later is
The memory (RAM) stores each cylinder at an address corresponding to the variable counter value. Therefore, for each cylinder, four pieces of combustion chamber pressure data are stored in the memory as shown by the broken lines in FIG. Then, the combustion chamber pressure is sequentially rewritten from old data to new data.

In S7, the average combustion chamber pressure (indicated by the thin line in FIG. 10) is calculated by simply averaging the four pieces of data stored in the memory for each cylinder.

Next, to explain the flowcharts of FIGS. 5 and 6, in Sll of FIG. Read the combustion chamber pressure just before the start of combustion.

Here, the output torque of the engine is detected from the combustion chamber pressure just before combustion starts. Further, at 521 in FIG. 6, the engine rotational speed is read based on the manual cycle of the reference signal from the crank angle sensor 7.

Next, the flowchart shown in FIG. 7 will be explained.

In S31, the rotational difference NVAR between the engine rotational speed read in step 521 and the target rotational speed is calculated.

In S32, the calculated rotational difference N V - A R is added to the previous rotational integral value to calculate a new rotational integral value. Further, the NPI is calculated by adding an integral obtained by multiplying a constant by 10 to the newly obtained rotational integral value, and a proportional component obtained by multiplying the rotational difference NVAR by a constant Kll.

In S33, the average combustion chamber pressure of each cylinder calculated in S7 is added and then divided by the number of cylinders to calculate the total average combustion chamber pressure TOTALAVE.

334, for each cylinder, the total average combustion chamber pressure TOTA
The deviation CYLVAR is calculated by subtracting the average combustion chamber pressure of that cylinder from LAVE. In addition, a new CYL integral value is calculated for each cylinder by adding the deviation CYLVAR calculated for each cylinder and the previous CYLQ value. moreover,
By adding the integral obtained by multiplying the constant by 20 to the calculated CYL integral value, and the proportional component obtained by multiplying the constant by 21 to the deviation CYLVAR, CYLPI is calculated so that the output torque of all cylinders is approximately the same for each cylinder. Calculate so that Therefore, the total average combustion chamber pressure TOTALAVE corresponds to the required output torque.

In S35, the calculated CYLPI and the value obtained by multiplying the constant by 30 are added to the actuator 5.
The control value of A is calculated for each cylinder.

Then, the calculated control value (opening timing of the second opening/opening valve 5)
A control signal corresponding to this is output to the actuator 5A of the corresponding cylinder at the timing shown in FIG. 11, and the opening degree of the second on-off valve 50 is controlled for each cylinder.

Changes in the opening degree of the second on-off valve 5 and changes in the intake pressure downstream of the throttle valve 2 during such control will be explained with reference to the time chart of FIG. 11. In this explanation, an example will be given when the throttle valve 2 is fully closed, that is, during idling operation, and in FIG. 11, intake indicates the intake stroke, compression indicates the compression stroke, explosion indicates the explosion stroke, and exhaust indicates the exhaust stroke. .

That is, in the explosion stroke, exhaust stroke, etc., the second on-off valve is fully opened so that the intake pressure downstream of the throttle valve at the start of the intake stroke is close to atmospheric pressure. Then, the second on-off valve is closed to a predetermined opening degree with a delay of a predetermined crank angle d1 from the start of the intake stroke. As a result, the intake pressure decreases as the piston descends, and at the end of the intake stroke, P
It becomes l. This intake pressure P1 corresponds to the intake air flow rate introduced into the combustion chamber.

In such opening degree control, when the actual engine rotational speed is higher than the target rotational speed and the intake air flow rate is greater than the required final amount, in the next intake stroke, the second crank angle is set at a crank angle d3 earlier than the predetermined crank angle d2. Fully close the on-off valve. As a result, the intake pressure at the end of the intake stroke becomes pz, which is lower than the above-mentioned P, so the intake air flow rate decreases and the engine rotational speed approaches the target rotational speed with good responsiveness.

By changing the timing at which the opening degree of the second on-off valve is changed, the intake air flow rate can be controlled with high precision while simplifying the control. The reason why this high-precision control of the intake air flow rate is possible is that when the second on-off valve is switched from fully open to a predetermined opening, the intake pressure downstream of the second on-off valve is near atmospheric pressure, so the differential pressure between the upper and lower sides of the second on-off valve is This is because the flow rate of intake air flowing through the bypass passage is small, so even if the timing is changed, the flow rate of intake air does not change significantly (poor sensitivity).

Incidentally, the intake air flow rate of the bypass passage 4 may be controlled as described above by controlling the actuator 5A using an on/off duty signal.

Next, an example of the hardware tank bottom of the control device 6 is
This will be explained based on FIG.

That is, after the cylinder pressure at a predetermined crank angle is averaged for each cylinder by the averaging processing zone gllA-11D, the adder 12 adds them together.

After calculating the pressure difference for each cylinder by subtracting the average pressure for each cylinder from the calculated average pressure for all cylinders using differentiators 14A and 14B, the proportional and integral parts of the pressure difference for each cylinder are calculated. are processed by the PI processing circuits 15A-15D, respectively.

Further, after the difference between the actual engine rotation speed detected by the crank angle sensor 7 and the target rotation speed is calculated by the differentiator 16, the proportional part and the integral part of this rotation speed difference are calculated by the PI processing circuit 17. calculate. Then, adders 18A to 18D add the proportional and integral parts of the pressure difference and the proportional and integral parts of the rotational speed difference to obtain a correction value for each cylinder,
This controls the actuator 5A.

As explained above, the second on-off valve 5 is disposed for each cylinder in the bypass passage 4 that bypasses the throttle valve 2, and the intake path downstream of each throttle valve 2! The volume of l is the maximum volume of the combustion chamber, which is 172
and fully open the second on-off valve 5 so that the intake pressure downstream of the throttle valve 2 at the time the intake valve 3 opens is close to atmospheric pressure, and during the intake stroke, the second on-off valve 5 is opened to a predetermined opening degree. Since the valve is driven to close, the following effects can be obtained.

That is, when the intake valve 3 begins to open, the combustion chamber pressure (
As the piston descends, the combustion chamber pressure changes from atmospheric pressure to the combustion chamber pressure at the bottom dead center position of the piston during idling (e.g. -550 It decreases almost linearly to -570□H,). Therefore, pumping loss can be significantly reduced compared to changes in intake pressure due to conventional throttle valve control alone, and period output can be maximized. Furthermore, since the second on-off valve 5 of the bypass passage 4 is controlled by the electromagnetic actuator 5A, the structure can be simplified compared to the conventional one.

Here, the reason why the volume of the intake passage 1 from the throttle valve 2 to the intake valve 3 is set to 172 or less, which is the maximum volume of the combustion chamber, will be explained. Assume that the maximum volume of the combustion chamber is A, that the volume of the intake passage l from the throttle valve 2 to the intake valve 3 is B, that the compression ratio is 1/10, and that the piston bottom dead center during idling operation is Combustion chamber pressure (intake pressure) at position -456,,
The explanation will be made on the assumption that H, (in a high-speed engine, the valve over-ramp period is long, so the value is about this value).

That is, the total volume of the intake passage 1 and the combustion chamber at the piston top dead center is (A/11B) -, and the total volume of the intake passage 1 and the combustion chamber at the piston bottom dead center is (A
+8). Under such conditions, the atmospheric pressure (1 atm) decreases by -4
When the combustion chamber pressure and intake pressure change to 56□H, (0.4 atm), (A/10+B)/(A+B)=0
．． 4, and solving this results in A=2B.

Therefore, when the volume of the intake passage 1 is less than or equal to the maximum volume of the combustion chamber, which is about 172, it is possible to ensure the optimum combustion chamber pressure at the piston bottom dead center position during low load operation such as idling operation.

In addition, since the deviation (deviation) CYLVAR is calculated for each cylinder from the total average combustion chamber pressure TOTALAVE of all cylinders, the combustion chamber pressure of each cylinder approaches the total average combustion chamber pressure TOTALAVE. , the combustion chamber pressure can be made almost the same in all cylinders. This makes it possible to make the output torque of all cylinders substantially the same, thereby stabilizing the drivability during idling operation. Further, after determining the rotational difference (deviation) NVAR of the engine rotational speed of each cylinder from the target rotational speed, NPI is determined for each cylinder, and the NPI that depends on the engine rotational speed is added to the control value of the actuator 5A. This makes it possible to make the engine rotational speeds of all cylinders substantially the same, which also makes it possible to stabilize the drivability during idling operation.

In addition, in each cylinder, the combustion chamber pressure is detected and the control value of the actuator 5A is determined for each combustion stroke (reference signal) to control the second on-off valve 5. Therefore, the output torque of each cylinder is and the engine rotational speed can be made substantially the same with good responsiveness, and this also makes it possible to stabilize the drivability during idling operation.

Next, a non-inventive embodiment will be described using specific examples and comparing with conventional examples.

That is, the first embodiment is for when the near conditioner (external load) is turned on and off as shown in FIG. 13, whereas in the conventional example, when the air conditioner is turned on during idling operation, A preset air conditioner correction amount (see Fig. 13) is added to the control amount of the auxiliary air control valve in the bypass passage that bypasses the throttle valve using soed forward correction to increase the intake pressure downstream of the throttle valve. However, with this type, the intake pressure cannot be controlled in response to the opening/closing timing of the intake valve, so the intake pressure increases only gradually after the near conditioner is turned on, resulting in a significant drop in engine speed (see Figure 13). There is a problem. On the other hand, in the non-invention, the second on-off valve 5
is driven to open and close every combustion stroke, and the intake pressure when the intake valve 3 begins to open is always controlled to approximately atmospheric pressure, so the output torque can be controlled with good responsiveness even immediately after the near conditioner is turned on. The drop in engine rotational speed can be greatly reduced (see No. 13M), and idle stability can be improved.

In addition, the second embodiment is for acceleration driving as shown in the 14th garden, and conventionally, when acceleration driving is performed especially in a low gear position, a phenomenon in which the vehicle vibrates in the longitudinal direction during acceleration driving (hereinafter referred to as (referred to as longitudinal vibration) occurs as shown in FIG. This occurs when the vehicle's drive system vibrates at its natural frequency due to the torque applied by the engine. In contrast, in the present invention, an output torque pattern that cancels the natural frequency is set in advance in correspondence with the acceleration driving state, and the output torque pattern is set from the start of acceleration driving (for example, detected from the operation amount of the accelerator pedal). So that it becomes? ! If the output torque is feedback-controlled by controlling the second on-off valve, longitudinal vibration during acceleration operation can be greatly suppressed (see No. 14i1).

Here, it is possible to suppress the longitudinal vibration by correcting the control amount of the conventional auxiliary air control valve, but in this case, the intake air flow rate cannot be controlled in synchronization with the opening/closing timing of the intake valve, so the output torque can be improved. Because it cannot be controlled properly, longitudinal vibration cannot be sufficiently suppressed.

The specific configuration for implementing this embodiment will be explained based on FIG. 15. In response to signals such as the amount of operation of the accelerator pedal, on/off of the near conditioner, and gear position, the target torque setting device 31 adjusts the engine speed. A target output torque corresponding to the generated output torque is determined in time series and is output to the control device 32. The control device 32 opens and closes the second on-off valve of each cylinder via the electromagnetic actuator 5A by feedback control so that the actual output torque (in this case, the combustion chamber pressure) becomes equal to the human-powered target output torque.

In addition, in the present invention, it is possible to suppress the rotation drop prevention 1 back-and-forth vibration during idling, and it is possible to perform control with a very high degree of freedom.

In the embodiment, the required output torque of the engine was detected from the combustion chamber pressure, but an oxygen sensor that detects the air-fuel ratio from the intake pressure, intake air flow rate, and engine air-fuel ratio (for example, the oxygen concentration in the exhaust gas) Alternatively, the second on-off valve may be controlled based on the actual output torque, or the amount of accelerator pedal operation by the driver may be detected. In addition, a second on-off valve is interposed in the bypass passage that bypasses the throttle valve.
An opening valve may be interposed.

<Effects of the Invention> As explained above, the present invention has the second on-off valve 5 interposed in the communication passage that communicates with the intake passage downstream of the first on-off valve provided for each cylinder. With this configuration, pumping loss can be significantly reduced and output torque can be increased, and the intake air flow rate can be controlled for each cylinder. In addition, since the second on-off valve of each cylinder is driven and controlled based on the detected required torque, the output torque of each cylinder can be controlled with good responsiveness, which improves drivability and provides freedom in engine control. You can increase the degree.

[Brief explanation of drawings]

Fig. 1 is a diagram corresponding to the claims of the present invention, Fig. 2 is a configuration diagram showing an embodiment of the present invention, Fig. 3 is an enlarged view of the main parts of the same, and Fig. 4 is a diagram corresponding to the claims of the present invention.
7 to 7 are flowcharts as above, FIGS. 8 to 11 are action explanatory diagrams as above, FIG. 12 is a hardware configuration diagram as above, FIG. 13 is an explanatory diagram of a second embodiment of the invention, 14th
The figure is an explanatory diagram of a second embodiment of the present invention, and FIG. 15 is a configuration diagram for implementing the embodiment. Fig. 1 1... Intake passage 2... Throttle valve 3... Intake valve 4... Bypass passage 5... 2nd M closing valve 5A
...Actuator 6...Control device

Claims (1)

[Claims] In an internal combustion engine in which an intake valve is opened when a piston descends to draw air into a combustion chamber, a first opening/closing valve is provided for each cylinder and opens/closes an intake passage communicating with the intake valve of each cylinder, and a first opening/closing valve for each cylinder is provided for each cylinder. A communication passage that communicates at least with the intake passage downstream of the valve, second on-off valves that open and close these communication passages, drive means that drives these second on-off valves, and output torque detection means that detects the required output torque of the engine. and a control means for driving and controlling each of the second on-off valves for each combustion stroke via the drive means based on the detection result of the output torque detection means. Control device.