JP2000186581A - Throttle control apparatus for vehicular engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a throttle control apparatus for a vehicular engine, which can implement vehicular acceleration performance of approximately equal to an accelerator operating amount regardless of a kind of fuel used, and can improve feel of accelerator operation of a driver. SOLUTION: According to preset maps MAP-Pe, MAP-θthP, and MAP-θthR, target throttle opening Tθth is obtained based on an accelerator operating amount Acc to control throttle opening. A knock interpolation coefficient Kk learned from a knock retard amount for suppressing knocking is used for interpolation processing between the map MAP-θthP and the map MAP-θthR. Therefore, the target throttle opening Tθth on an opening side is determined according to a retard angle of ignition timing Tig to compensate lowering of an engine output caused by the retard angle.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a throttle control device for a vehicle engine that controls the opening of a throttle valve in accordance with the operation amount of an accelerator pedal.

[0002]

[Related Background Art] As is well known, gasoline used for vehicle engines can be broadly classified into premium gasoline and regular gasoline according to the octane number. For vehicles designated as premium gasoline, the knock resistance of the gasoline is maximized. The engine's compression ratio, ignition timing, etc. are set in order to achieve high output, achieving high output. However,
Even if it is a premium gasoline designated car, regular gasoline may be replenished, so in such a case, in a premium gasoline designated car, the presence or absence of knocking is determined based on the detection information of the knock sensor, and knock determination is made. The ignition timing is retarded when knocking is reduced to suppress knocking.

[0003]

However, retarding the ignition timing causes a decrease in the engine output. To obtain the same acceleration performance as when using premium gasoline,
The driver needs to depress the accelerator more. In other words, when the driver performs the same accelerator operation when using premium gasoline and when using regular gasoline, the acceleration of the vehicle is higher when using regular gasoline (large retard) than when using premium gasoline (small retard). , And there is a problem that an uncomfortable feeling is given to the accelerator operation.

An object of the present invention is to provide a vehicle engine capable of realizing approximately the same acceleration of a vehicle with respect to an accelerator operation amount regardless of the type of fuel used, thereby improving the driver's accelerator operation feeling. To provide a throttle control device.

[0005]

In order to achieve the above object, the present invention provides an accelerator operation amount detecting means for detecting an accelerator operation amount, a throttle adjusting means for adjusting a throttle opening, and a preset accelerator operation amount. The throttle control means controls the operation of the throttle adjustment means based on the accelerator operation amount detected by the accelerator operation amount detection means in accordance with the throttle opening characteristic with respect to the amount, and is executed by the ignition timing control means to suppress knocking. Throttle opening correction means for correcting the throttle opening by the throttle control means to the open side in accordance with the control amount of the retard control. For example, the ignition timing is retarded by the ignition timing control means as the octane value of the gasoline being used is lower and knocking is more likely to occur, but the throttle opening is corrected to the open side according to the control amount at this time. Therefore, the decrease in engine output due to the retard is compensated,
A substantially equal engine output is maintained even with the same accelerator operation amount.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is embodied in a throttle control device for a direct injection gasoline engine will be described below. In FIG. 1, reference numeral 1 denotes an in-cylinder injection gasoline engine for an automobile, in which a combustion chamber 2, an intake system and the like are designed exclusively for in-cylinder injection. This engine 1
Since the compression ratio and the like are set on the premise of premium gasoline, the use of premium gasoline is specified for vehicles equipped with the engine 1. The cylinder head 3 of the engine 1 is provided with an electromagnetic fuel injection valve 5 together with an ignition plug 4 for each cylinder. High-pressure fuel supplied from a fuel pump (not shown) is supplied from the fuel injection valve 5 to the combustion chamber 2. It is designed to be injected directly into the interior.

[0007] An intake port 6 is formed in the cylinder head 3 in a substantially upright direction, and an intake passage 7 is connected to the intake port 6. A throttle valve 8 for adjusting the amount of intake air is provided in the intake passage 7, and the throttle valve 8 is opened and closed by a motor 9. The intake air taken in from the intake passage 7 is introduced into the combustion chamber 2 from the intake port 6 with the opening of the intake valve 10 via the throttle valve 8 and fuel is injected from the fuel injection valve 5 into the intake air. Then, the fuel is burned by the ignition of the spark plug 4.

The cylinder head 3 has an exhaust port 15
Are formed in a substantially horizontal direction, and an exhaust passage 16 is connected to the exhaust port 15. The exhaust gas after combustion is discharged from the combustion chamber 2 to the atmosphere via the exhaust port 15, the exhaust passage 16, and a catalyst and a muffler (not shown) as the exhaust valve 17 is opened. In the passenger compartment, an input / output device (not shown), a storage device (ROM, RAM, BURAM, etc.) for storing control programs and control maps, and a central processing unit (C
An ECU (engine control unit) 21 provided with a PU (Pull Input / Output Unit), a timer counter, and the like is installed to perform comprehensive control of the engine 1. On the input side of the ECU 21, an accelerator sensor 22 as an accelerator operation amount detecting means for detecting the operation amount Acc of the accelerator pedal by the driver, a crank angle sensor 2 for outputting a crank angle signal at every predetermined crank angle
3. Various sensors such as a knock sensor 24 for detecting vibration when knocking occurs due to combustion of the fuel are connected, and information on their detection is input.

The output side of the ECU 21 is connected to the above-described ignition plug 4 via an igniter 25 and an ignition coil 26, and also connected to a fuel injection valve 5. or,
An output side of the ECU 21 is connected to an ETV-CU (electronic throttle valve control unit) 27,
A throttle position sensor 28 for detecting an opening degree θth of the throttle valve 8 is connected to an input side of the throttle valve 27, and the motor 9 is connected to an output side of the throttle position sensor 28. In the present embodiment, the ETV-CU 27 and the motor 9 function as throttle adjusting means.

The ECU 21 determines the fuel injection mode (representing the process of performing the fuel injection, as described later) and the fuel injection time based on the detection information from each sensor, and controls the drive of the fuel injection valve 5. In addition, the basic ignition timing θB is determined based on the detection information from each sensor, and the ignition timing Tig is determined from the basic ignition timing θB and the knock retard amount θk corresponding to the occurrence of knocking.
5 is driven and controlled. Further, the target average effective pressure Pe is determined based on the detection information from each sensor, and the target throttle opening degree Tθth is determined from the target average effective pressure Pe and the engine rotation speed Ne and output to the ETV-CU 27 side. The ETV-CU 27 controls the drive of the motor 9 based on the information.

A map for determining various parameters used in the above-described fuel injection control, ignition timing control, and throttle opening control is stored in the storage device of the ECU 21. Here, as maps correlated with the gist of the present invention, there are maps used for ignition timing control and throttle opening control, and the setting status of these maps will be described below.

FIG. 2 is a block diagram schematically showing the functions of the ECU 21 for controlling the throttle opening and controlling the ignition timing. As shown in this figure, regarding the ignition timing control, two maps MAP-θB are used to determine the basic ignition timing θB.
P and MAP-θBR are stored. These maps MAP-θB
P and MAP-θBR are set according to the type of gasoline (premium gasoline and regular gasoline). Although not shown, knocking is suppressed in the regular map MAP-θBR compared to the premium map MAP-θBP. Therefore, it is set so as to determine the basic ignition timing θBR on the more retarded side.

As for the throttle opening control, one kind of map MAP-Pe for determining the target average effective pressure Pe and the target throttle opening T using the target average effective pressure Pe.
Two types of maps MAP-θthP and MAP-θt for determining θth
hR is stored. As with the maps MAP-θBP and MAP-θBR of the basic ignition timing θB described above, the target throttle opening T
The maps MAP-θthP and MAP-θthR of θth are set corresponding to the type of gasoline.

Although not shown, the premium map MAP-
The regular map MAP-θthR is set so as to determine a larger target throttle opening Tθth as compared with θthP. As will be described in detail later, its characteristic is a map MAP-θBP that determines the basic ignition timing θB. , MAP-θBR is set so as to be able to compensate for the decrease in engine output due to the retardation of the ignition timing.

Next, the state of execution of the throttle opening control executed by the throttle control device configured as described above will be described. The knock interpolation coefficient Kk used in the previous operation is backed up by a battery in the storage device of the ECU 21. When the engine 1 is started, the ECU 21
The ignition timing control unit reads the knock interpolation coefficient Kk from the storage device and calculates the map MAP-θB according to the following equation (1).
Interpolation processing between P and MAP-θBR is performed, and the basic ignition timing θB
Ask for.

ΘB = KkθBP + (1−Kk) θBR (1) where θBP is the basic ignition timing obtained from the premium map MAP-θBP, and θBR is the regular map MAP-θBR.
This is the basic ignition timing determined from. In addition, each map MAP-θB
For P and MAP-θBR, engine speed Ne and volumetric efficiency E
The basic ignition timings θBP and θBR are determined based on V.
Then, the ECU 21 calculates the ignition timing Tig by adding various correction amounts to the obtained basic ignition timing θB, and controls the drive of the igniter 25 based on the ignition timing Tig.

In parallel with this processing, the ECU 21 determines whether or not knocking has occurred based on the output signal of the knock sensor 24, and determines the knock retard amount θk set in accordance with the determination result with the ignition timing. Used for calculating Tig. That is, as is well known, when the output signal of knock sensor 24 exceeds a predetermined threshold value within a determination period immediately after ignition, it is considered that knocking has occurred, and knock retard Tg is increased and ignition timing Tig is delayed. Correct to the corner side. By repeating this control, knocking is suppressed, and the ignition timing Tig is held at the value immediately before knocking occurred. In the present embodiment, when executing the above-described retardation processing, E
The CU 21 functions as ignition timing control means.

Based on the setting of the knock retard amount θk at this time, the ECU 21 determines the knock interpolation coefficient K
Execute the learning process of k. The execution condition is engine 1
Is set in accordance with the fuel injection mode of. Although not described in detail, the in-cylinder injection type engine 1 can execute a compression stroke injection mode for performing combustion at a very lean air-fuel ratio (stratified combustion) of about 40 in addition to the normal intake stroke injection mode. These fuel injection modes are switched based on the target average effective pressure Pe (representing a load) of the engine 1 and the engine speed Ne. Specifically, the compression stroke injection mode is executed to reduce fuel consumption in a low load / low rotation range, and the intake stroke injection mode is switched to a higher range in order to reduce the air-fuel ratio as the load and rotation speed increase. (Lean mode), stoichiometric air-fuel ratio (SF / B mode), rich (O /
(L mode).

The learning process of the knock interpolation coefficient Kk is executed in the intake stroke injection mode while avoiding the compression stroke injection mode in which the load is low and the knocking frequency is low. As shown in FIG. 3, a different knock learning determination value EV0 is preset as a function of the engine rotation speed Ne in accordance with each mode in the intake stroke injection mode and a combination of a correction direction of the ignition timing Tig based on the knock retard amount θk. Have been. At the time of execution of the intake stroke injection mode, the ECU calculates the volumetric efficiency EV at that time based on the engine speed Ne and the output of an air flow sensor (air amount sensor) (not shown).
When the calculated volume efficiency EV is equal to or larger than the knock learning determination value EV0 (EV ≧ EV0), it is determined that the learning condition is satisfied.

When the learning condition is satisfied, the ECU 21 sets the knock retard amount θk at that time to a predetermined threshold value θ0.
And the knock retard amount θk is equal to or greater than the threshold value θ0 (θk ≧
In the case of θ0), the knock interpolation coefficient Kk is decreased, the basic ignition timing θB is corrected to the retard side, and is smaller than the threshold value θ0 (θk ≦ θ0).
In this case, the knock interpolation coefficient Kk is increased, the basic ignition timing θB is corrected to the advanced side, and the basic ignition timing θB calculated from the equation (1) is optimized. Therefore, the lower the octane number of the gasoline being used and the easier it is for knocking to occur,
Since the knock interpolation coefficient Kk is learned to a small value to determine the basic ignition timing θB on the retard side, the engine output decreases. Thus, the knock interpolation coefficient Kk
Can be regarded as an index indicating the type of gasoline used.

On the other hand, the throttle opening control unit of the ECU 21 determines the map MAP- based on the accelerator operation amount Acc detected by the accelerator sensor 12 and the engine rotation speed Ne calculated from the crank angle signal of the crank angle sensor 23.
The target average effective pressure Pe is determined according to Pe. Further, an interpolation process between the maps MAP-θthP and MAP-θthR is executed according to the following equation (2) using the above-mentioned knock interpolation coefficient Kk, and a target throttle opening Tθth is obtained.

Tθth = KkTθthP + (1−Kk) TθthR (2) Here, TθthP is a target throttle opening obtained from the premium map MAP-θthP, and TθthR is obtained from the regular map MAP-θthR. This is the target throttle opening.
In each of the maps MAP-θthP and MAP-θthR, the target throttle opening Tθth is determined based on the engine rotation speed Ne and the target average effective pressure Pe. The ECU 21 inputs the obtained target throttle opening degree Tθth to the ETV-CU 27,
The TV-CU 27 performs feedback control based on the target throttle opening Tθth and the throttle opening θth detected by the throttle position sensor 28,
The actual throttle opening θth is converted to the target throttle opening Tθth
Adjust to

As described above, the target throttle opening Tθth
Is performed by applying the same knock interpolation coefficient Kk as in the case of the basic ignition timing θB, and the maps MAP-θthP and MAP-θthR used at this time are output reduction due to the retardation of the basic ignition timing θB. The characteristic is set so as to calculate a target throttle opening degree Tθth which is larger by an amount corresponding to.

Therefore, for example, when regular gasoline is used, the basic ignition timing θB is set to a considerably retarded side in order to suppress knocking, but a large target throttle opening Tθth is set accordingly, and the actual throttle opening is set. Since θth is corrected to the open side, a decrease in engine output due to retarding is compensated, and substantially the same engine output is maintained even with the same accelerator operation amount Acc. As a result, the same acceleration can be achieved by the same accelerator operation as when using premium gasoline, and the driver can operate the accelerator with the same feeling without feeling uncomfortable, thereby greatly improving the accelerator operation feeling.

In the present embodiment, the above knock interpolation coefficient Kk
The ECU 21 at the time of executing the process of correcting the throttle opening θth based on the above functions as a throttle opening correcting means. This concludes the description of the embodiment, but aspects of the present invention are not limited to this embodiment. For example, in the above-described embodiment, the present invention is embodied as a throttle control device of the direct injection gasoline engine 1, but may be embodied as a throttle control device applied to a normal engine that injects fuel into an intake port.

In the above embodiment, the knock retard amount θk
Map MAP using knock interpolation coefficient Kk learned from
Although the target throttle opening Tθth was obtained by interpolating between -θthP and MAP-θthR, it is possible to compensate for the decrease in engine output due to the retarded ignition timing Tig caused by changing the fuel used. The processing content is not limited as long as the target throttle opening Tθth can be determined. Therefore, for example, without using the knock interpolation coefficient Kk, the correction coefficient set in accordance with the knock retard amount θk
The target throttle opening TθthP obtained from the premium map MAP-θthP may be corrected to the open side.

[0027]

As described above, according to the throttle control apparatus for a vehicle engine of the present invention, almost the same acceleration of the vehicle with respect to the accelerator operation amount is realized regardless of the type of fuel used. It is possible to improve the driver's accelerator operation feeling.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram showing a throttle control device for a vehicle engine according to an embodiment.

FIG. 2 is a block diagram schematically showing functions of a throttle opening control and an ignition timing control of an ECU.

FIG. 3 is an explanatory diagram showing setting conditions for a knock learning determination value.

[Explanation of symbols]

Reference Signs List 1 engine 9 motor (throttle adjustment means) 21 ECU (throttle opening correction means, ignition timing control means) 22 accelerator sensor (accelerator operation amount detection means) 27 ETV-CU (throttle adjustment means) Kk knock correction coefficient (control amount)

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (reference) F02D 43/00 301 F02D 43/00 301B 301K F02P 5/152 F02P 5/15 D 5/153 F term (reference) 3G022 AA03 DA02 EA02 FA06 GA01 GA05 GA06 GA13 3G065 AA04 CA21 DA05 DA06 EA07 EA10 FA12 GA05 GA10 GA16 GA41 HA21 HA22 JA04 JA09 KA02 KA12 KA33 3G084 AA03 BA05 BA17 DA03 EA11 EB12 EC03 FA07 FA03 FA01 FA03 FA01 LB04 LC03 MA01 NC04 NC06 ND03 ND22 NE01 NE12 NE13 NE14 NE15 PA01Z PA11A PC08Z PE01Z PE03Z PF03A

Claims (1)

[Claims] An accelerator operation amount detecting means for detecting an accelerator operation amount by a driver; a throttle adjusting means for adjusting an engine throttle opening degree; and the accelerator opening amount characteristic according to a preset throttle opening degree characteristic with respect to an accelerator operation amount. Throttle control means for controlling the operation of the throttle adjustment means based on the accelerator operation amount detected by the operation amount detection means; and retard control control executed by the ignition timing control means to suppress knocking. And a throttle opening correction means for correcting the throttle opening by the throttle control means to the open side.