JP2762582B2 - Control device for internal combustion engine for vehicles - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a control device for an internal combustion engine for a vehicle, and more particularly, to a control device configured to control an intake air amount based on a detection result of an accelerator operation amount. About.

<Conventional Technology> As such a control device for an internal combustion engine for a vehicle, there is the following device as described below.

That is, as a method of controlling the torque characteristic and the output characteristic of the engine with respect to the accelerator operation amount to characteristics preferable for the drivability of the vehicle, for example, as disclosed in Japanese Patent Application Laid-Open No. Sho 60-1922843, There is a device that determines the opening of the throttle valve in accordance with the rotation speed and controls the drive of the throttle valve so as to match the set opening.

Further, in the Japanese Unexamined Utility Model Publication No. 62-193151, the governor of a diesel engine is controlled in the same manner as the throttle valve opening control.

<Problems to be Solved by the Invention> However, in such a conventional control device for a vehicle internal combustion engine, there is a case where an accelerator operation is performed such that the torque suddenly changes due to the characteristics of the engine itself. Although it is possible to control the actually generated torque characteristic to a preferable form, the response characteristic of the engine speed to the accelerator operation amount can be set to an arbitrary preferable response characteristic while avoiding vehicle vibration in an arbitrary driving range. There was a problem that they could not be freely matched.

That is, if the responsiveness of the engine rotation speed to the accelerator operation amount is set low, the longitudinal vibration of the vehicle can be satisfactorily avoided, but if the responsiveness is low, the driver may feel uncomfortable or poor response. For example, vehicle vibration is generated due to sensitive response characteristics in some driving regions, but the overall response level is set relatively high to avoid discomfort due to the response delay, thereby ensuring response. In addition, the best rotational speed responsiveness cannot be secured while avoiding vehicle vibration in each driving region. In addition, although the rotational response characteristic or the favorite rotational response characteristic that is easy to drive varies depending on the driver, there has been a problem that the response characteristic of the rotational speed cannot be switched according to the individual preference of the driver.

The present invention has been made in view of the above problems, and enables a response characteristic of an engine rotation speed to an accelerator operation amount to be selected from a plurality of reference models according to a driver's preference and a driving state, so that a vehicle can be selected. The purpose is to further enhance drivability.

<Means for Solving the Problems> Therefore, in the present invention, as shown in FIG. 1, an accelerator operation amount detecting means for detecting an accelerator operation amount, an engine rotational speed detecting means for detecting an engine rotational speed, and an accelerator Target engine speed setting means for setting the target engine speed based on the accelerator operation amount detected by the operation amount detection means, and detection by the engine speed detection means when the accelerator detected by the accelerator operation amount detection means is fully closed Reference engine speed storage means for storing the set engine speed as a reference engine speed, and a target for calculating a target deviation which is a difference between the set target engine speed and the stored reference engine speed. Deviation calculating means, actual deviation calculating means for calculating an actual deviation which is a deviation between the detected engine speed and the stored reference engine speed, A response characteristic selecting means for selecting a reference model of a response characteristic of the actual deviation with respect to the target deviation from a plurality of types stored in advance, and for causing the actual deviation to match the target deviation with the selected response characteristic. Target torque setting means for setting a target engine output shaft torque based on the actual deviation, the target deviation and the response characteristics of the selected reference model; and an intake air amount of the engine for obtaining the set target engine output shaft torque. And the intake air amount control means for controlling the internal combustion engine.

<Operation> According to the control device having such a configuration, while setting the target engine speed based on the accelerator operation amount, the engine speed when the accelerator is fully closed is set as the reference engine speed, and the reference engine speed and the actual engine speed are set. The deviation from the rotation speed (actual deviation)
Control is performed so as to approach a deviation (target deviation) between the reference engine rotation speed and the target engine rotation speed. Here, a response characteristic when the actual deviation approaches the target deviation is selected from a plurality of types, and the target engine output shaft torque is set so that the actual deviation approaches the target deviation with the selected response characteristic. The intake air amount of the engine is controlled so as to obtain the engine output shaft torque.

<Examples> Examples of the present invention will be described below.

In FIG. 2 schematically showing the system configuration of one embodiment, a crank angle sensor 2 as an engine rotation speed detecting means for detecting a crank angle and a rotation speed Ne of an engine 1, and an operation amount (depressed amount) of an accelerator pedal (not shown). a, for example, an accelerator operation amount sensor 3 as an accelerator operation amount detecting means for detecting an output voltage of a potentiometer, and an opening degree θR of a throttle valve 5 provided in an intake passage 4 of the engine 1.
Sensor 7 and a reference model selection switch 7 as a response characteristic selection means are provided. Detection signals and selection signals from these sensors and switches are input to the CPU 8a of the microcomputer 8. I have.

Here, the CPU 8a selects a reference model of response characteristics of the engine rotation speed from a plurality of types based on the reference model selection switch 7, and sets a target engine rotation speed based on an accelerator operation amount. The engine speed at the time when the accelerator is fully closed (reference engine speed) is stored. Furthermore,
From these, the target deviation between the target engine rotation speed and the reference rotation speed and the actual deviation between the actual engine rotation speed and the reference rotation speed are calculated.

Then, the target engine output shaft torque is set based on the actual deviation, the target deviation, and the reference model so that the response change of the engine speed from the actual deviation to the target deviation matches the selected reference model. The target throttle valve opening that gives the amount of intake air necessary to output torque is read from the throttle valve opening table 8b and output to the servo drive circuit 9 to control the amount of intake air via the opening of the throttle valve 5. I do.

Therefore, in this embodiment, the microcomputer 8
Has functions as a reference engine rotational speed storage unit, a target engine rotational speed setting unit, an actual deviation calculating unit, a target deviation calculating unit, and a target torque setting unit.
The intake air amount control means includes a servo drive circuit 9 and a servo motor.
10, consisting of a throttle valve 5.

Further, the microcomputer 8 outputs an ignition signal to the ignition coil 11 based on the crank angle signal output from the crank angle sensor 2 to control the ignition timing by the ignition plug 12 by a known method, and Fuel supply control performed by outputting a fuel injection signal to the injector 13 is simultaneously performed.

The throttle valve opening degree table 8b is provided with a target throttle valve opening degree θo such that an intake air amount necessary for generating the target torque can be obtained if the momentary target torque and the engine speed Ne are given. This is stored on the ROM.

The servo drive circuit 9 is connected to the rotation axis of the throttle valve 5 according to the deviation between the opening θR of the throttle valve 5 detected by the throttle sensor 6 and the target throttle valve opening θo input from the microcomputer 8. The servo motor 10 is driven to rotate forward and reverse so that the opening of the throttle valve 5 follows the target value.

Next, according to the program shown in FIG. 3, setting of the target engine speed Ner, calculation of the actual deviation ΔNe and the target deviation ΔNer,
Each calculation process of setting the target engine output shaft torque Tec and setting the target throttle valve opening θo will be described.

The program shown in FIG. 3 is executed at regular intervals, for example, every 10 ms. First, at P1, the operation amount (opening) a of the accelerator pedal detected by the accelerator operation amount sensor 3 is read.

At P2, the engine speed Ne is calculated based on the crank angle signal from the crank angle sensor 1.

In P3, based on a signal from the reference model selection switch 7, a reference model showing a response characteristic when the actual engine rotation speed approaches the target engine rotation speed (specifically, a response characteristic of an actual deviation with respect to a target deviation described later). Is selected from a plurality of types previously set and stored. Here, when the response characteristic of the reference model is a second-order delay system as shown in the following equation, if the time constant Ta is switched and set by the reference model selection switch 7, the reference model having excellent responsiveness can be obtained. Alternatively, a reference model showing a relatively insensitive response can be arbitrarily selected from a plurality of types.

In the following equation, τP is a dead time required for the engine 1 to generate torque, and s is a Laplace operator.

Here, the selection of the reference model (selection of the time constant Ta) may be performed by automatic switching based on an operating state such as a vehicle speed or a gear ratio in addition to manual switching by the switch 7. The driver can switch the response characteristics of the rotational speed according to the driver's preference, while automatically switching according to the driving conditions ensures the best response characteristics in each driving area while avoiding vehicle driving. Becomes possible.

At P4, the target engine speed Ner is calculated from the accelerator operation amount a according to the following equation.

Ner = k1 · a Here, k1 is a constant that defines the magnitude of the convergence value of the engine speed Ne, and may be switched according to the preference of the driving vehicle or the traveling environment.

At P5, the engine speed Ne when the accelerator is fully closed (when the accelerator operation amount is zero) is stored as the reference engine speed Neo.

At P6, the engine speed Ne calculated at P2, that is,
The deviation (actual deviation) ΔNe (= Ne−Neo) of the latest detected value of the engine speed Ne from the reference engine speed Neo is calculated.

In P7, the deviation (target deviation) ΔNer (= Ner−N) of the target engine rotation speed Ner calculated in P4 from the reference engine rotation speed Neo
eo).

In P8, when the engine rotational speed Ne changes in response from the actual deviation ΔNe calculated as described above to the target deviation ΔNer, the engine rotational speed Ne changes along the reference model H (s). The target engine output shaft torque Tec is calculated using a known feedback system control as shown in FIG.

In FIG. 4, H (s) is a reference model of the selected response characteristic, and G (s) is an approximate model of the engine 1 such as the following equation. Here, G (s) represents a response characteristic from setting of the target engine output shaft torque Tec to obtaining the corresponding engine rotation speed Ne.

Here, τa is a response delay time constant of the engine intake air amount, τ
p is the dead time that the engine 1 has to generate torque, Je
Is a moment of inertia of the drive system, and τc is a constant depending on an external load.

Actually, G (s), M (s) (= H (s) / G (s))
To the sampling cycle Tsmp (0, which is the execution cycle of this program).
The target engine output shaft torque (engine output shaft torque instruction value) Tec is calculated using GD (z) and MD (z) converted to a discrete time system in 01 sec). Where z is a delay operator,
(K) shows time series data.

Tec (k) = MD (z) · (ΔNer (k) − (ΔNe (k) −GD (Z) · T
ec (k-1)) That is, the actual deviation ΔNe is corrected in consideration of the response delay from the command of the control torque until the corresponding engine rotation speed Ne is obtained, and the actual deviation ΔNe is replaced with the target ΔNer. The engine output shaft torque, which is the control target for matching, is determined by the response characteristic of the selected reference model so that the engine speed ΔNe is ΔNe.
It is set to change the response up to r. Therefore, the same ΔN
Even if e and ΔNer, the response characteristic changes while the rotation speed Ne converges to the target according to the selected response characteristic reference model.

In P9, the target throttle valve opening θo is read from the throttle valve opening table 8b based on the engine speed Ne calculated in P2 and the target engine output shaft torque Tec calculated in P8. As shown in FIG. 5, the throttle valve opening table 8b reads out the target throttle valve opening θo based on the target engine output shaft torque Tec and the engine rotation speed Ne. The data is stored in the engine 1 mounted on the vehicle. Is determined from the steady-state performance of the engine (the engine output shaft torque is plotted when the accelerator operation amount and the engine speed Ne are constant).

Thus, according to the present embodiment, when the reference model of the response characteristic of the desired engine speed Ne is selected by the selection switch 7, the time constant representing the selected response characteristic is obtained.
According to Ta, the actual deviation ΔNe and the target deviation ΔNer, and the engine characteristic model, a response change of the rotation speed for matching the current ΔNe to the target deviation ΔNer is obtained with a characteristic according to the time constant Ta. Rotation speed according to driver's preference
If the response characteristics of Ne can be switched and the response characteristics (reference model) can be automatically switched according to the driving conditions, the best responsiveness in each driving area can be avoided while avoiding unpleasant vibration of the vehicle. Can be obtained.

Also, when controlling the engine speed Ne to the target engine speed Ner, without using an absolute value, a deviation from the reference rotation speed Neo when the accelerator is fully closed is obtained, and the actual deviation approaches the deviation at the target rotation speed Ner. Thus, when performing control using the engine characteristic model based on the engine torque, it is possible to suppress the influence of the modeling error on the actual engine 1.

In the above embodiment, the target engine output shaft torque Tec is set so that the response characteristic of the engine speed Ne matches the selected reference model, and the opening of the throttle valve 5 is controlled based on this. However, when a speed change mechanism such as a manual transmission or a continuously variable transmission (CVT) is connected to the engine, the speed ratio of the speed change mechanism is detected to detect the vehicle speed. Control can be performed to make the response characteristics match the reference model as in the case of the engine speed Ne.

<Effects of the Invention> As described above, according to the present invention, while setting the target engine speed based on the accelerator operation amount, the engine speed when the accelerator is fully closed is set as the reference engine speed, and the reference engine speed is set. The deviation (actual deviation) between the speed and the actual engine rotation speed approaches the deviation (target deviation) between the reference engine rotation speed and the target engine rotation speed by the response characteristic of the selected reference model. By setting the target engine output shaft torque and controlling the intake air amount so as to obtain the target engine output shaft torque, the reference model can be selected according to the driver's preference, or the operating condition can be selected. In this case, the response characteristic of the engine speed with respect to the accelerator operation amount can be made to match any desirable response characteristic while avoiding vehicle vibration in an arbitrary driving range. Vehicle drivability can be obtained.

In addition, since the comparison between the target rotation speed and the actual rotation speed is performed based on the deviation from the same reference rotation speed, the engine for matching the response characteristics of the actual rotation speed to the response characteristics of the reference model is used. In modeling, it is possible to minimize the adverse effect of the modeling error on the engine control.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of the present invention, FIG. 2 is a system schematic diagram showing a system configuration of an embodiment of the present invention, and FIG.
FIG. 4 is a flowchart showing the control contents in the embodiment of the present invention. FIG. 4 is a functional explanatory block diagram for explaining control characteristics in the embodiment. FIG. 5 is a setting state of a target throttle valve opening in the embodiment. FIG. 3 is a diagram showing an example of the above. 1 ... Engine 2 ... Crank angle sensor 3 ... Accelerator opening sensor 5 ... Throttle valve 6 ... Throttle sensor 7 ... Reference model selection switch 8 ... Microcomputer 8a CPU , 8b… throttle valve opening table, 9… servo drive circuit, 10… servo motor

Claims (1)

(57) [Claims] 1. An accelerator operation amount detecting means for detecting an accelerator operation amount, an engine speed detecting means for detecting an engine speed, and a target for setting a target engine speed based on the detected accelerator operation amount. Engine speed setting means; reference engine speed storage means for storing the engine speed detected when the accelerator is fully closed detected by the accelerator operation amount detecting means as a reference engine speed; and the set target engine Target deviation calculating means for calculating a target deviation that is a deviation between a rotational speed and the stored reference engine rotational speed; and a deviation between the detected engine rotational speed and the stored reference engine rotational speed. Actual deviation calculating means for calculating an actual deviation; and a response for selecting a reference model of a response characteristic of the actual deviation with respect to the target deviation from a plurality of types stored in advance. Gender selecting means, based on the actual deviation, the target deviation, and the response characteristic of the selected reference model, the target engine output shaft torque for matching the actual deviation with the target deviation in the selected response characteristic. A target torque setting means for setting, and an intake air amount control means for controlling an intake air amount of the engine to obtain the set target engine output shaft torque. Control device.