JPH01110832A - Output control of internal combustion engine equipped with turbocharger - Google Patents

Abstract

PURPOSE:To always control the engine output to a necessary output by setting an aimed sucked air quantity corresponding to the detected opening degree of a throttle valve and the detected engine revolution speed and adjusting the operation quantity of an actuator according to the difference between the aimed sucked air quantity and the detected sucked air quantity. CONSTITUTION:The valve opening degree of a throttle valve 15 arranged midway in an intake passage, engine revolution speed, and the intake air quantity are detected, and an aimed sucked air quantity corresponding to the valve opening degree of the throttle valve 15 and the detected engine revolution speed is set. The supercharge pressure is controlled by adjusting the operation of an actuator 24 which opening/closing-drives a waste gate valve 22 according to the difference between the detected sucked air quantity and the aimed sucked air quantity. Since the sucked air quantity is directly controlled by this method, the engine output can be correctly controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for controlling the output of an internal combustion engine equipped with a turbocharger.

(Prior Art and its Problems) Conventionally, an internal combustion engine is known in which intake air supplied to an internal combustion engine is supercharged by a turbocharger to improve acceleration performance and output characteristics. In order to control the supercharging pressure (boost pressure) of an internal combustion engine equipped with this turbocharger, a wastegate valve is used to open and close the bypass passage that bypasses the turbine of the turbocharger. An actuator is provided, the pressure chamber of the actuator and the intake passage downstream of the compressor during turbocharging are connected by a boost pressure introduction pipe, and a three-way switching valve is disposed in the middle of the boost pressure introduction pipe, An output control device is known in which the operating pressure supplied from the intake passage downstream of the compressor to the pressure chamber of the actuator, and therefore the operating amount of the actuator, is adjusted by controlling the opening and closing of this three-way switching valve by electronic control means. It is being

This output control device stores, for example, a target boost pressure value corresponding to the engine rotation speed and the throttle valve opening in advance in a storage device of the electronic control means, and stores the engine rotation speed detection value and the throttle valve opening detection value in advance. Read the target boost pressure according to the target boost pressure, engine coolant temperature,
It is corrected by multiplying a correction coefficient based on various input information such as the throttle valve opening speed and the amount of knock occurrence, and is calculated according to the deviation between the calculated target boost pressure and the actual boost pressure detected by the intake pressure sensor. The three-way switching valve is controlled on and off to adjust the operating pressure supplied to the actuator, and the boost pressure is controlled to the target boost pressure by opening and closing the wastegate.

The output control method using this output control device requires an expensive intake pressure (boost pressure) sensor and also corrects the target boost pressure read from the map using various input information as described above. There is a problem that the processing becomes programmatically complicated.

That is, when performing engine control, it is desirable to control the intake air weight, which is a direct control variable, but the control method of this conventional output control device uses an indirect control variable, that is,
The boost pressure is controlled, so if the atmospheric pressure drops, for example at high altitudes, the exhaust pressure will drop for the same boost pressure, resulting in a withdrawal force, which will cause problems with engine durability. When the intake air temperature is low, it becomes an exit force. Therefore, it is necessary to correct the atmospheric pressure and intake air temperature.
Correction based on these various input information requires complex arithmetic processing in consideration of the intake air 1i1.

Another conventional output control device is to supply boost pressure to a Niematic actuator that opens and closes the wastegate valve, and opens and closes the wastegate valve according to the boost pressure. There is known an output control device that controls boost pressure by forcibly opening and closing a wastegate valve by a required valve opening degree in accordance with various parameters such as wide open throttle (WOT), amount of knock occurrence, and the like.

This output control device is basically a so-called pneumatic actuator control, and the system is simple because most of the control is to open and close the wastegate valve using only boost pressure. High precision is required for the actuator that is forced to open and close, and the degree of freedom in control is lower than that of the first control device described above.Furthermore, since the control using this method is oven loop control, the boost pressure may be excessively high. Some kind of check mechanism is required for overboosting and the like.

In addition, this second control device also controls an indirect control amount, that is, the valve opening of the wastegate, and therefore,
When atmospheric pressure decreases at high altitudes, exhaust pressure decreases for the same boost pressure, resulting in insufficient output. Moreover, when the intake air temperature is low, it becomes a withdrawal force, and a complicated correction calculation process of atmospheric pressure and intake air temperature is required for the control parameter wastegate valve opening.

The present invention was made to solve these problems, and it does not complicate the calculation process in the control program, and it can accurately output the required output intended by the driver even if the atmospheric pressure or intake air temperature changes. It is an object of the present invention to provide a method for controlling the output of an internal combustion engine equipped with a turbocharger designed to be controllable.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides an internal combustion engine that controls boost pressure by adjusting the operating amount of an actuator that opens and closes a waste gate valve of a turbocharger. In an engine output control method, the valve opening, engine speed, and intake air weight of a throttle valve disposed in the middle of the intake passage are respectively detected, and the system is operated according to the detected throttle valve opening and the detected engine speed. Output control of an internal combustion engine equipped with a turbocharger, characterized in that a target intake air weight is set, and an operating amount of the actuator is adjusted according to a deviation between the set target intake air weight and the detected intake air weight. A method is provided.

(Function) The output control method of the present invention directly controls the intake air weight, which is the control target of the engine, and adjusts the amount of actuation of the actuator according to the deviation between the detected intake air weight and the target intake air weight. This allows precise output control to adjust and drive the wastegate to open and close.

(Example) Hereinafter, one embodiment of the present invention will be described based on the drawings.

First, the schematic configuration of the output control device for carrying out the method of the present invention will be explained with reference to FIG. and a turbine 10b that drives the machine 10a. The compressor 10a is disposed midway through the intake pipe 12, and the turbine 10b is disposed midway through the exhaust pipe 14.

An air cleaner (not shown) is attached to the end of the intake pipe 12 that is open to the atmosphere, and a Karman vortex type air flow sensor 16 is also attached, which supplies a Karman vortex generation cycle signal to an electronic control unit 20, which will be described later. A throttle valve 15 is disposed in the intake pipe 12 between the atmosphere open end and the compressor 10a of the turbocharger 10, and a throttle opening sensor 18 detects the valve opening of the throttle valve 15 and sends a detection signal to the electronic control unit. Supply to 2o.

The exhaust pipe 14 has ten turbines 1 during turbocharging.
A bypass passage 14a that bypasses the exhaust pipe 14 is connected to the bypass passage 14a, and a wastegate valve 22 is disposed at a connection port where the downstream side of the bypass passage 14a and the exhaust pipe 14 meet. It is opened and closed. The wastegate valve 22 is connected by a rod 23 to a diaphragm 24a of a pneumatic actuator 24.

The actuator 24 includes a casing 24b, the aforementioned diaphragm 24a, and an atmospheric chamber 24d, which define the inside of the casing 24b into a pressure chamber 24c and an atmospheric chamber 24d.
A spring 24f is housed in the spring 24f and presses the diaphragm 24a to move the wastegate valve 22 in the direction of closing it.
It consists of

One end of a boost pressure introduction pipe 26 is connected to the pressure chamber 24c of the actuator 24, and the other end of the introduction pipe 26 is connected to a port 12 provided in the intake pipe 12 downstream of the turbocharger 10.
a, and the introduction pipe 26 is connected to the turbocharger 10
The downstream internal pressure of the intake pipe 12, that is, the boost pressure, is introduced into the pressure chamber 24c as the operating pressure (at the branch point 26 in the middle of the introduction pipe 26).
A pipe line 27 is connected to a, and an electromagnetic cutoff valve 28 is disposed in the middle of the pipe line 27.

! The magnetic cutoff valve 28 includes a valve body 28a that shuts off the pipe line 27, a spring 28b that always presses the valve body 28a in the closing direction, and a spring 28b that opens the valve body 28a against the spring force of the spring 28b when biased. Solenoid 28c
c is connected to the output side of the electronic control unit 20. The electromagnetic cutoff valve 28 is controlled by a drive signal from the electronic control unit 20, and a part of the boost pressure guided to the pressure chamber 24c by the introduction pipe 26 is released to the intake pipe 12 on the upstream side of the turbocharger 10, and the pressure chamber is released. The magnitude of the operating pressure acting on 24c is adjusted.

The diaphragm 24a of the actuator 24 is connected to the pressure chamber 2.
The wastegate valve 22 is opened and closed via the rod 23, and is displaced in accordance with the magnitude of the operating pressure introduced into the valve 4c.

On the input side of the electronic control unit 20, in addition to the air flow sensor 16 and the throttle opening sensor 18,
an engine rotation speed sensor 30 that detects the engine rotation speed;
An intake temperature sensor 31 that detects intake air temperature, an atmospheric pressure sensor 32 that detects atmospheric pressure, etc. are connected, and detection signals from these various sensors are sent to the electronic control unit 20.
is supplied to

The electronic control unit 20 includes a central processing unit (CPU), a storage device such as a ROM and a RAM (not shown), and an I1
The electronic control unit 20 controls the operation of an internal combustion engine (not shown) by executing a control program stored in a storage device, such as an output control routine to be described later.

Next, the output control procedure for the internal combustion engine according to the present invention will be described as follows.
This will be explained with reference to the flowchart shown in the figure.

First, the electronic control unit 20 executes step 40 in FIG. read the degree signal θth, etc., and store them in the storage device.

Next, from the target (^/N) map, the target intake air weight (per cylinder) per intake stroke according to the detected engine speed value Ne and the detected throttle valve opening value θth is determined.
A/N) value is read out (step 41).

FIG. 3 shows the conceptual structure of the target (A/N) map stored in the storage device of the electronic control unit 20, and shows how these maps correspond to one engine speed Ne and j throttle valve openings θth. A target intake air weight (A/N) value is stored corresponding to each set of values. Then, from this target (^/N) map, a target intake air weight (A/N) value corresponding to the engine speed Ne and throttle valve opening θth detected by, for example, a known four-point interpolation method is read out and calculated. Ru. The calculated target intake air type M (A
/N) value is corrected for air density based on the intake air temperature detected by the intake air temperature sensor 31 and the atmospheric pressure detected by the atmospheric pressure sensor 32 as necessary (step 43).

Next, the actual weight of intake air taken into the engine is calculated from the Karman vortex generation period f detected by the air flow sensor 16, the intake air temperature detected by the intake temperature sensor 31, and the atmospheric pressure detected by the atmospheric pressure sensor 32. death,
Deviation Δ(A/N) between this actual intake air weight (A/N) and the target intake air weight (A/N) calculated and corrected in step 43.
N) is calculated, and the duty correction amount ΔD (ΔD-f(Δ(A/N))) of the electromagnetic cutoff valve 28 is calculated from this deviation (step 45). Then, the process proceeds to step 47, where the target (A/N) is calculated. N) Read the target duty rate according to the detected engine rotational speed value Ne and the detected throttle valve opening value θth from the target duty map of the map and the fellows.

FIG. 4 shows the conceptual structure of the target data map stored in the storage device of the electronic control unit 20, and similarly to the target (A/N) map, one engine rotation speed Ne and j throttle valve openings are shown. Target duty ratio values are respectively stored for θth corresponding to these value sets. Then, from this target duty map, a target duty rate value corresponding to the engine rotational speed Ne and the throttle valve opening θth detected by, for example, a known four-point interpolation method is read out and calculated.

The electronic control unit 20 calculates the actual duty rate D' that actually drives the electromagnetic cutoff valve 28 from the target duty rate and the duty correction amount ΔD obtained as described above using the following equation (step 49).

D' - D + ΔD Then, the electronic control unit 20 drives the electromagnetic cutoff valve 28 according to the actual duty rate D° calculated in this way (
Step 50), when the electromagnetic cutoff valve 28 is at the actual duty rate D°
When the duty is controlled in
Actuator 2 leaks into the upstream intake pipe 12 of 0.
The diaphragm 24a of No. 4 moves, and the wastegate valve 22 is driven to the closing side or the opening side in accordance with an increase or decrease in the duty rate D'. As a result, the rotational speed of the IO during turbocharging increases or decreases in a direction in which the weight of intake air supplied to the engine matches the target intake air weight.

Note that the sensor for detecting the intake air weight is not limited to the above-mentioned Karman vortex type air flow sensor 16, and a hot wire type air flow sensor or the like may be used. It is advantageous to use a sensor that can directly detect air weight, as there is no need to compensate for changes in atmospheric pressure.

Also, by changing the map value of the target (A/N) map shown in Fig. 3 to an appropriate value, the relationship between the accelerator depression amount (throttle valve opening) and engine output can be changed by adjusting the throttle lever, throttle bore diameter, and bore number. A desired relationship can be set using software without changing the parameters. That is,
As shown in FIG. 5, for example, when the engine speed is maintained at a constant low speed (for example, 1500 rpm), the throttle valve opening θth changes along the change of the characteristic curve A in FIG. When the value is small, the increase in the intake air weight (A/N) is small, and as the value increases, the intake air weight (A/N) increases.
A/N) can be set so that the increase is large, or as shown in characteristic curve B, the throttle valve opening θt
It is also possible to set a linear relationship between the change in h and the change in the intake air weight (^/N).

Furthermore, as shown in characteristic curve C in Fig. 5, the intake air weight (A/N) is increased while the throttle valve opening θth is small, and as the value increases, the intake air weight (^/N) is increased.
) can also be set so that the increase is small.

Further, the actuator for opening and closing the waste gate valve 22 is not limited to the Niematic actuator 24 as in this embodiment, but may be driven by a pulse motor or the like.

(Effects of the Invention) As detailed above, according to the output control method of an internal combustion engine equipped with a turbocharger of the present invention, the valve opening of the throttle valve disposed in the intake passage, the engine speed, and the intake air A target intake air weight is set according to the detected throttle valve opening degree and the detected engine speed, and the waste gate valve is set according to the deviation between the detected intake air weight and the target intake air weight. Since the boost pressure is controlled by adjusting the operating amount of the actuator that drives the opening and closing, the air flow sensor, throttle opening sensor, engine speed sensor, etc. that are conventionally used for fuel supply control etc. can be used as they are. There is no need to use special sensors such as expensive boost pressure sensors, and since the intake air weight, which is directly controlled by the engine, is controlled, the engine output can be accurately controlled, and the intake air temperature can be controlled. Variations in intake air weight and therefore output are small in response to changes, and there is no need to worry about exit force at extremely low temperatures, and even when atmospheric pressure drops at high altitudes, the same output as on flat land can be obtained. It will be done. Furthermore, matching tests are made easier for various input information such as engine speed, throttle valve opening, turbocharger characteristics, and atmospheric pressure.Furthermore, accelerator depression amount (throttle valve opening)
FIG. 1 is a flowchart showing the output control procedure of an internal combustion engine equipped with a turbocharger according to the present invention, and FIG. 2 is a flowchart showing the engine output control procedure for implementing the method of the present invention. A block diagram showing the configuration of the device, Figure 3 shows the target (^/N) value map for setting the target intake air weight, the engine rotation speed Ne,
Throttle valve opening θth and target intake air weight (A/N
), a graph showing the relationship between engine rotational speed N e % of the target duty map for setting the target duty rate, a graph showing the relationship between the throttle valve opening θth and the target duty rate value, and Figure 5 shows the relationship between the throttle valve opening θth and the target duty rate value. It is a graph showing the relationship between the degree θth and the intake air weight (^/N) value.

10...turbocharger, 10a...compressor, 1
0b... Turbine, 12... Intake pipe, 14... Exhaust pipe, 15... Throttle valve, 16... Air flow sensor, 18... Throttle opening sensor, 20...
Electronic control unit, 22... Waste gate valve, 24... Actuator, 26... Boost pressure introduction pipe, 28... Electromagnetic cutoff valve, 30... Engine speed sensor, 31... Intake temperature Sensor, 32...
Atmospheric pressure sensor.

Applicant: Mitsubishi Motors Corporation Agent Patent Attorney Kanji Nagamon Figure 2 Throttle valve opening θTH Procedural amendment language and behavior) December 8, 1988

Claims (1)

[Claims] In an internal combustion engine output control method that controls boost pressure by adjusting the operating amount of an actuator that opens and closes the wastegate valve of a turbocharger, the valve opening degree and engine speed of a throttle valve located in the intake passage are used. and the intake air weight, and set a target intake air weight according to the detected throttle valve opening and the detected engine speed, and calculate the deviation between the thus set target intake air weight and the detected intake air weight. 1. A method for controlling the output of an internal combustion engine equipped with a turbocharger, the method comprising: adjusting the amount of operation of the actuator according to the amount of operation of the actuator.