JP2930256B2 - Engine throttle valve controller - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine throttle valve control device for controlling a throttle valve provided in an intake passage and opened and closed by a throttle valve driving means.

[0002]

2. Description of the Related Art Conventionally, a throttle valve control device of an engine in which a throttle valve provided in an intake passage is driven by an electric actuator such as a motor and the throttle valve is electrically controlled by a control unit is known. Various are known. In this type of device, the accelerator operation amount is detected, and the throttle opening is controlled accordingly. In some cases, the throttle opening is corrected in accordance with other factors. For example, JP-A-61-
In the device disclosed in Japanese Patent No. 87938, the throttle opening is corrected to be larger as the engine temperature is lower, in accordance with the engine temperature. The reason for this is to increase the engine output at low temperatures where the flammability tends to deteriorate.

[0003]

As described above, there is an apparatus in which the throttle opening is corrected for adjusting the engine output in accordance with the engine temperature or the like, but the fuel transport delay has been sufficiently considered in the prior art. I didn't. That is,
When the fuel volatility is poor or when the fuel easily adheres to the intake pipe, the transportation delay until the fuel supplied from the fuel injection valve or the like reaches the combustion chamber increases. When the opening of the throttle valve suddenly changes due to depression of the accelerator pedal during acceleration, the fuel does not follow the increase in the intake air amount corresponding thereto, and the air-fuel mixture fed into the combustion chamber becomes lean, There was a problem that drivability deteriorated.

[0004] The fuel injection amount is conventionally corrected in accordance with the state of fuel adhesion to the intake pipe related to the transport delay, but such correction is performed when the transport delay increases. Also, when the amount of intake air changes suddenly, it cannot follow the change.

An object of the present invention is to solve the above-mentioned problem, and to prevent the air-fuel ratio from being deviated due to abrupt operation of a throttle valve when fuel transport delay is large, and to maintain good operability. It is an object of the present invention to provide a throttle valve control device for an engine capable of performing the following.

[0006]

In order to achieve the above object, the present invention comprises an air flow sensor for detecting the amount of intake air in an intake passage, a throttle valve, and a fuel injection valve, and the throttle valve is electrically connected. An engine comprising: a throttle valve driving unit that is opened and closed by an actuator; and a unit that controls the throttle valve driving unit in accordance with the accelerator operation amount based on a throttle opening characteristic that specifies a correspondence between an accelerator operation amount and a throttle opening. In the above, transport delay detecting means for detecting a fuel transport delay by detecting a parameter related to the fuel transport delay, a basic fuel injection amount is calculated according to the intake air amount detected by the air flow sensor, and Calculates final fuel injection amount by correcting fuel injection amount according to parameters related to fuel transport delay The fuel injection amount control means, it is determined whether the transport delay detected by the transport delay detection means is large, when it is determined that the fuel transport delay is large, compared to when the fuel transport delay is small, Control means for controlling the throttle valve driving means so as to slow down the opening / closing operation of the throttle valve so that the rate of change of the throttle valve opening with respect to the change of the accelerator operation amount becomes small.

The control means includes a first throttle opening characteristic as a characteristic of the throttle opening with respect to the accelerator operation amount, and a change rate of the throttle opening with respect to the change in the accelerator operation amount as compared with the first throttle opening characteristic. Is controlled by selectively using the second throttle opening characteristic which is small, and when the fuel transport delay is small, the throttle valve is controlled using the first throttle opening characteristic to transport the fuel. When the delay is large, the throttle valve is preferably controlled using the second throttle opening degree characteristic.

It is preferable that the transport delay detecting means detects a transport delay related to a fuel vaporization state. For example, the transport delay detecting means detects the volatility of the fuel and detects the transport delay of the fuel based on the volatility. Alternatively, the amount of fuel attached to the intake pipe is detected,
The fuel transport delay is detected based on the amount of fuel attached to the intake pipe. Alternatively, the fuel vaporization state may be checked based on the engine temperature to detect a fuel transport delay.

[0009]

According to the above configuration, the fuel injection amount is controlled in accordance with the intake air amount, and the fuel injection amount is corrected in accordance with the parameter related to the fuel transport delay, and the transport delay is particularly large. In this case, the intake air amount and the fuel injection amount are appropriately controlled at the time of acceleration or the like by controlling the change in the throttle valve opening to be slower in response to a change in the accelerator operation amount due to an acceleration operation or the like. .

[0010]

An embodiment of the present invention will be described with reference to the drawings.
FIG. 1 schematically shows the entire apparatus. In this figure, each cylinder of an engine body 1 has a combustion chamber 3 above a piston 2.
Are formed. The combustion chamber 3 is provided with a spark plug 4 and has an intake port communicating with the intake passage 5 and an exhaust port communicating with the exhaust passage 6. These ports are connected to an intake valve 7 and an exhaust valve 8. Is opened and closed.

In the intake passage 5, a fuel injection valve 9 is disposed near an intake port on the downstream side, and a throttle valve 10 is provided upstream of the fuel injection valve. The throttle valve 10 is driven by an electric actuator 11 such as a servomotor.
An electric throttle driver 12 that controls energization according to a control signal is provided. Actuator 11 above
And the electric throttle driver 12 constitute a throttle valve driving means.

Reference numeral 15 denotes a control unit for controlling the throttle valve 10, which comprises an input port 16, an output port 17, a CPU 18, a RAM 19, a ROM 20, and the like, and is formed using a microcomputer or the like.
The control unit 15 includes an air flow meter 21 provided in the intake passage 5 for detecting an intake air amount, a rotation speed sensor 22 for detecting an engine speed, and an accelerator for detecting an accelerator operation amount (a depression amount of an accelerator pedal 13). Signals from a sensor 23, a throttle opening sensor 24 for detecting the opening of the throttle valve 10, a water temperature sensor 25 for detecting the temperature of the engine cooling water, a starter switch 26 for detecting the operation of the starter, and the like are input. The control unit 15 outputs a signal for operating the throttle valve 10 to the electric throttle driver 12.

FIG. 2 is a block diagram functionally showing the configuration of the control system. In this figure, a control unit 15 outputs a control signal to a fuel injection valve 9 as a fuel injection amount control means, and functions as a transport delay detecting means 31 for detecting a fuel transport delay. It has a function as a control means 32 for changing the throttle valve opening / closing operation accordingly. In the present embodiment, the transport delay detecting means 31 checks the volatility of the fuel and detects a transport delay caused by the deterioration of the volatility. Specifically, as will be described in detail later, it is determined whether the fuel is a light fuel with good volatility or a heavy fuel with low volatility by examining the engine speed fluctuation situation immediately after the start. Furthermore, since the volatility of heavy fuel is improved at high temperatures and the difference from light fuel is reduced, the case of heavy fuel and low temperature is considered as a case where transport delay is increased, taking water temperature into consideration. doing.

The control means 32 is configured to slow down the throttle valve opening / closing operation by changing the throttle opening characteristic with respect to the accelerator operation amount when the transport delay is increased due to poor fuel volatility. .
That is, the control of the throttle valve outputs a control signal to the throttle driver 12 for setting the throttle opening in accordance with the accelerator operation amount based on the throttle opening degree characteristic in which the relationship between the accelerator operation amount and the throttle opening degree is predetermined. However, two types of throttle opening characteristics shown in lines A and B in FIG. 3 are preset and stored in the control unit 15. Among them, the first throttle opening characteristic shown by the line A is that the throttle opening change rate with respect to the change of the accelerator operation amount is relatively large,
In the second throttle opening characteristic shown by the line B, the rate of change of the throttle opening with respect to the change in the accelerator operation amount is smaller than that of the first throttle opening characteristic. When the fuel volatility is good, the first throttle opening characteristic is selected, whereas when the fuel volatility is bad, the second throttle opening characteristic is selected.

A specific example of the control by the control unit 15 is shown in the time chart of FIG. 4 and the flowcharts of FIGS.

FIG. 5 shows a routine of heavy fuel discrimination relating to the function of the transport delay detecting means 31. In this routine, it is determined whether or not the fuel is heavy by examining fluctuations in the engine speed immediately after starting. The outline of this process will be described with reference to the time chart of FIG. 4. At startup, the engine speed once rises, and after startup, the engine speed decreases to some extent. In this case, if the light fuel is used, the change in the rotation speed becomes gradual after falling below the predetermined rotation speed (first reference rotation speed) N1 (broken line 41), whereas the heavy fuel is used. If so, even if the combustion speed deteriorates, the rotation speed rapidly decreases even after the rotation speed falls below the first reference rotation speed N1 (solid line 42), and the second reference rotation speed (from the first set rotation speed N1) within a predetermined time Ta. Is also reduced to a value lower than the predetermined number of revolutions) N2. This rotation speed fluctuation is checked by the routine of FIG.

When the routine shown in FIG. 5 starts, the control unit 15 first determines the start by examining the engine speed signal and the starter switch signal, and sets the start flag Fst to "1" when starting (see FIG. 5). Steps S1 and S2). Next, in step S3, the engine speed Ne is read, and in step S4, it is determined whether the engine speed Ne is lower than the first reference speed N1. If this determination is NO, the process returns to step S1.

If the determination in step S4 is YES, it is determined in step S5 whether the start flag Fst is "1". When the start flag Fst is "1", the flag Fst is set to "0" in step S6, a predetermined time Ta is set in the timer T, and when the flag Fst becomes "0", the process proceeds to step S7. Timer T by judgment
Unless becomes "0", the timer T is decremented in step S8. That is, when the engine speed falls below the first reference speed N1 after the start, the timer T is set to the predetermined time Ta, and then the timer T is counted down.

Further, at step S9, the engine speed N
It is determined whether or not e is lower than the second reference rotation speed N2. While the engine speed is equal to or higher than the second set speed N2, the process returns from step S9 to step S1, and the process from step S1 is repeated, whereby the countdown of the timer T is repeated. If the engine speed Ne is kept equal to or higher than the second reference speed N2 until the predetermined time elapses, the determination in step S7 becomes YES, and
In this case, the heavy flag Fh is "0" in step S10.
It is said. On the other hand, when the engine speed Ne becomes lower than the second reference speed N2 during the predetermined time, step S1 is executed.
At 1, the heavy flag Fh is set to “1”.

FIG. 6 shows an auxiliary routine for determining the volatility based on the water temperature. In this routine, the water temperature K is read in step S12, and the water temperature K is set to the predetermined temperature K in step S13.
Check if it is higher than a. When the water temperature K is equal to or lower than the predetermined temperature Ka, the routine returns without changing the value of the heavy flag Fh determined in the routine of FIG. 5, but when the water temperature K becomes higher than the predetermined temperature Ka, step In S14, the heavy flag Fh is set to “0”.

FIG. 7 shows a throttle valve control routine based on the determination in the routines of FIGS. When this routine starts, in step S15, the heavy flag Fh
Is "1". And the heavy flag Fh
Is "0", in step S16, the first throttle opening degree characteristic is selected, and the throttle valve is controlled in accordance with the accelerator operation amount based on this characteristic. Increase the opening change rate. On the other hand, when the heavy flag Fh is “1”,
In step S17, the second throttle opening characteristic is selected, and the throttle valve is controlled in accordance with the accelerator operation amount based on this characteristic, so that the throttle opening change rate with respect to the change in the accelerator operation amount is reduced. That is, the operation of the throttle valve 10 is dulled.

According to the apparatus of the present embodiment as described above, the degree of the decrease in the engine speed immediately after the start of the engine is checked in the routine of FIG. 5, so that it is correctly determined whether the fuel is light or heavy. . Then, based on this determination and the temperature determination in the routine of FIG. 6, when the light fuel having good volatility is used, or when the heavy fuel is used, the volatility is improved due to the high temperature. When the first
The throttle valve 10 is controlled according to the accelerator operation amount according to the throttle opening characteristic of the throttle valve. On the other hand, if heavy fuel is used and the engine temperature is low, the fuel volatility is poor and the transport delay is large, the accelerator operation amount is reduced by the first throttle opening degree characteristic. Control of the throttle valve 10 is performed accordingly.
Therefore, when the volatility is low, when the accelerator pedal is depressed, the throttle opening increases slowly with the increase in the accelerator operation amount, and the intake air amount increases to match the fuel transport delay. Slows down. Thereby, leaning of the air-fuel ratio is prevented.

FIGS. 8 to 11 show a second embodiment. In this embodiment, the amount of fuel adhering to the intake pipe is detected, and the fuel transport delay is determined based on the detected amount. In other words, when the amount of fuel adhering to the intake pipe is small, even if the fuel is increased in accordance with an increase in the intake air amount during acceleration or the like, most of the fuel adheres to the intake pipe, so that the transport delay increases. As described above, since the amount of fuel adhering to the intake pipe is related to the transport delay, this is used as a parameter. Also in this embodiment, a device as shown in FIG. 1 is used as a hardware configuration, but the control unit 15 outputs a control signal (injection pulse) to the fuel injection valve 9 in addition to the control of the throttle valve 10. And control unit 1
5 calculates the amount of fuel attached to the intake pipe while controlling the fuel injection amount according to the intake air amount and the like. Then, as shown in FIG. 8, when the amount of fuel attached to the intake pipe is large, a throttle opening characteristic in which the rate of change of the throttle opening relative to the change in the accelerator operation amount is relatively large is selected. When the throttle opening is small, the throttle valve opening / closing operation is made slow by selecting a throttle opening characteristic in which the throttle opening change rate with respect to the change in the accelerator operation amount is relatively small.

The method of obtaining the amount of fuel adhering to the intake pipe in this embodiment will be outlined with reference to FIGS.

As shown in FIG. 9, the fuel injected from the fuel injection valve 9 is divided into an adhering amount F1 adhering to the wall surface of the intake pipe and a direct adsorbing amount F2 sucked directly into the combustion chamber 3. on the other hand,
The fuel adhering to the intake pipe is vaporized and becomes the combustion chamber 3
And the remaining fuel F4 which remains without being vaporized. Therefore, the combustion chamber 3 is actually
Is F2 + F3, and the amount of fuel attached to the intake pipe is F1 + F4. Further, the direct injection rate α, which is the ratio of the directly injected fuel F2 of the fuel injected from the fuel injection valve 9, and the carry-off rate β, which is the ratio of the aforementioned removed fuel F3 of the fuel attached to the intake pipe. Is determined by the intake flow velocity and temperature, the injection timing, and the like. For example, when the injection is performed in the intake stroke, the intake flow velocity Qcy and the temperature
0, characteristics as shown in FIG. Therefore, such characteristics are experimentally examined in advance and stored in the control unit 15 as maps, and the direct entry rate α and the carry-out rate β are obtained from these maps. As shown, the amount of fuel attached to the intake pipe is determined.

The calculation and control processing of this embodiment is shown in FIG.
This will be specifically described with reference to the flowchart of FIG. FIG. 12 also shows the processing as the fuel injection amount control means.

In the fuel control and calculation routine of FIG. 12, first, various signals are input in step S21, and in step S22, the charging efficiency Ce is obtained from the intake air amount, the engine speed, and the like. From the number, etc., the intake flow velocity Qc at the fuel injection valve arrangement location
Subsequently, in steps S23 and S24, the direct entry rate α and the carry-out rate β are calculated from maps such as those shown in FIGS. Subsequently, in step S25, the fuel injection amount (injection pulse width) is calculated. In this calculation, a basic injection amount is obtained according to the intake air amount and the engine speed, a required injection amount is obtained from the basic injection amount and various correction amounts, and the direct injection rate α, which is a parameter related to fuel transport delay, is calculated. Using the carry-out rate β, the final injection amount is calculated by performing a correction according to the transport delay so that the fuel actually supplied to the combustion chamber becomes the required amount. Following this calculation, step S2
Injection is performed in 6.

Further, in step S27, the amount of fuel τe injected from the fuel injection valve 9 and the amount of fuel already attached to the intake pipe (the value obtained in the previous process) τma,
From the above-mentioned direct entry rate α and carry-out rate β, the amount of fuel τm attached to the intake pipe is determined by the following equation.

Τm = (1−α) · τe + (1−β) · τma In the routine for controlling the throttle valve in FIG. 13, in step S28, the intake pipe calculated by the calculation in step S27 described above. The amount .tau.m of the attached fuel is read, and subsequently, in step S29, the throttle opening characteristic is set in accordance with the amount .tau.m of the attached fuel in the intake pipe. In this case, as shown in FIG. 8, the throttle opening degree characteristic may be switched in two stages depending on whether the amount τm of the fuel attached to the intake pipe is large or small, or as the amount τm of the fuel attached to the intake pipe decreases, The throttle opening characteristic may be changed in multiple stages so that the operation of the valve becomes dull.

Also in this embodiment, when the transport delay is increased due to a small amount of fuel adhering to the intake pipe, the operation of the throttle valve in response to the accelerator operation during acceleration or the like is slowed down, thereby reducing the air-fuel ratio. Leaning is prevented.

In addition to the above embodiments, the control for slowing down the opening / closing operation of the throttle valve when the transport delay is large based on the detection of the parameter related to the fuel transport delay, as shown in FIG. Alternatively, the throttle opening characteristic may be changed according to the engine temperature. In other words, in this example, the engine temperature is checked using a water temperature sensor or the like without performing heavy fuel determination, and the transport delay increases when the engine temperature is low. In the degree characteristic, the rate of change of the throttle opening degree with respect to the accelerator operation amount is smaller than the throttle opening degree characteristic when the engine temperature is high.

[0032]

As described above, according to the present invention,
The basic fuel injection amount is calculated according to the intake air amount detected by the air flow sensor, and the final fuel injection amount is calculated by correcting the fuel injection amount according to a parameter related to fuel transport delay. On the other hand, when the transport delay is large, the throttle valve driving means is controlled so that the change in the throttle valve opening becomes slower in response to a change in the accelerator operation amount due to an acceleration operation or the like. In a situation where it is not possible to follow a sudden change in the intake air amount even when the fuel injection amount is corrected, even if the accelerator operation amount changes suddenly during acceleration or the like, the change in the intake air amount is gradual. Thus, it is possible to prevent the drivability from being deteriorated due to the lean operation.

For example, if the volatility of the fuel is detected, or the amount of fuel adhering to the intake pipe is checked, or the engine temperature is checked to detect the transport delay related to the vaporization state, the vaporization state can be detected. By properly detecting the transport delay based on the parameters related to the above, and controlling the throttle valve accordingly, it is possible to appropriately prevent the transport delay due to the deterioration of the vaporization state from becoming lean.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an example of the overall structure of the device of the present invention.

FIG. 2 is a functional block diagram of a control system.

FIG. 3 is a diagram showing a relationship between throttle opening characteristics.

FIG. 4 is a time chart showing a change in engine speed immediately after engine start.

FIG. 5 is a flowchart showing a routine for heavy fuel determination.

FIG. 6 is a flowchart illustrating a routine for determining volatility based on water temperature.

FIG. 7 is a flowchart illustrating a routine of throttle valve control.

FIG. 8 is a diagram showing a throttle opening characteristic that can be changed according to the amount of fuel attached to an intake pipe in the case of the second embodiment.

FIG. 9 is an explanatory diagram showing a state of fuel in an intake passage.

FIG. 10 is a diagram showing a direct injection rate of fuel.

FIG. 11 is a diagram showing a fuel removal rate.

FIG. 12 is a flowchart showing a routine of fuel control and calculation according to the second embodiment.

FIG. 13 is a flowchart illustrating a throttle valve control routine according to the second embodiment.

FIG. 14 is a diagram showing a throttle opening characteristic that can be changed according to the engine temperature in the case of the third embodiment.

[Explanation of symbols]

 Reference Signs List 5 intake passage 9 fuel injection valve 10 throttle valve 11 actuator 12 electric throttle driver 15 control unit 31 transport delay detecting means 32 control means

────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Yuji Shiya 3-1 Shinchi, Fuchu-cho, Aki-gun, Hiroshima Mazda Co., Ltd. (72) Hideki Onoshi 3-1 Shinchi, Fuchu-cho, Aki-gun, Hiroshima Mazda Co., Ltd. (56) References JP-A-60-40745 (JP, A) JP-A-2-157448 (JP, A) JP-A-2-99745 (JP, A) JP-A-3-57831 ( JP, A) (58) Field surveyed (Int. Cl. ⁶ , DB name) F02D 9/02 F02D 11/10 F02D 41/04 310 F02D 45/00 364

Claims (6)

(57) [Claims] 1. An airflow detecting device for detecting an amount of intake air in an intake passage.
A low sensor, a throttle valve , and a fuel injection valve are provided, and the throttle valve is electrically operated by an electric actuator.
Throttle valve driving means that opens and closes with the accelerator, and accelerator operation
Throttle that specifies the correspondence between amount and throttle opening
Throttle valve according to accelerator operation amount based on opening characteristics
Means for controlling the driving means ,
Transport delay detecting means for detecting fuel transport delay by detecting a parameter related to fuel transport delay ;
According to the amount of intake air detected by the airflow sensor
To calculate the basic fuel injection amount, and
The fuel injection amount is corrected according to the parameters
A fuel injection amount control means for calculating a final fuel injection amount;
Whether the transport delay detected by the transmission delay detection means is large
And it was determined that the fuel transportation delay was large.
Accelerator operation compared to when fuel transportation delay is small.
The rate of change of the throttle valve opening with respect to the
In so that the throttle valve control apparatus for an engine is characterized in that a control means for controlling the throttle valve driving means so as to dull the opening and closing operation of the throttle valve. The control means includes a first throttle opening characteristic as a characteristic of a throttle opening with respect to an accelerator operation amount, and a throttle opening degree with respect to a change in the accelerator operation amount as compared with the first throttle opening characteristic. The control is performed by selectively using the second throttle opening degree characteristic having a small change rate.
Control the throttle valve using the throttle opening characteristics of
2. The throttle valve control device according to claim 1, wherein the throttle valve control device is configured to control the throttle valve using the second throttle opening degree characteristic when the fuel transport delay is large. 3. The engine throttle valve control device according to claim 1, wherein the transport delay detecting means detects a transport delay related to a fuel vaporization state. 4. The engine throttle valve control according to claim 3, wherein the transport delay detecting means detects the volatility of the fuel and detects a fuel transport delay based on the volatility. apparatus. 5. A transport delay detecting means for detecting an amount of fuel attached to an intake pipe and detecting a transport delay of fuel based on the quantity of fuel attached to the intake pipe. Engine throttle valve control device. 6. The throttle valve control device for an engine according to claim 3, wherein the transport delay detecting means detects a fuel vaporization state based on an engine temperature to detect a fuel transport delay.