JPH0799107B2 - Engine fuel supply controller - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a fuel supply control device for an engine, which increases the fuel supply amount to the engine when the engine is accelerated.

(Prior Art) Conventionally, as a fuel supply control device for an engine of this type, as disclosed in, for example, Japanese Patent Laid-Open No. 58-72630, the operating state of the engine is detected, and the acceleration of the engine is equal to or higher than a set value. It is known that during acceleration, the amount of fuel corresponding to the acceleration is increased to improve the responsiveness of the engine output and improve the acceleration performance.

(Problems to be Solved by the Invention) By the way, in the case of increasing the fuel amount during acceleration as described above, if the engine acceleration becomes less than a set value after acceleration, the amount of increased fuel during acceleration may be gradually reduced to perform tailing. It is preferable that the combustion state of the air-fuel mixture after acceleration is as stable as possible and the torque shock can be effectively reduced.

However, in that case, when setting a fixed rate to reduce the amount of increase in fuel after acceleration, for example, for a predetermined amount of time or a predetermined number of revolutions, the drivability and emission performance are reduced depending on the operating state after acceleration. It may decrease.
That is, in the above-mentioned conventional one, in the relationship of determining the presence or absence of acceleration by comparing the engine acceleration with a set value, the operating state after the acceleration of a predetermined value or more, and a case where it shifts to a steady state as it is, There are two types of slow acceleration, in which the intake air amount is gradually increasing when the acceleration is less than the set value.Therefore, in the former steady state, there is little change in the intake air amount, Since the amount of the increased fuel is gradually decreased, the air-fuel ratio of the air-fuel mixture becomes overrich. In this case, if the decrease rate of the increased fuel is increased, this problem will be solved. However, in this case, in the latter slow acceleration, the decrease rate of the increased fuel is large against the increase change of the intake air amount. As a result, the air-fuel ratio of the air-fuel mixture is over leaned, resulting in a decrease in drivability.

The present invention has been made in view of such a point, and an object thereof is not to make the reduction rate of the increased fuel after acceleration a fixed rate,
By changing appropriately according to the operating state after acceleration,
Even after acceleration, the intake air amount and the fuel supply amount are always well matched to maintain the air-fuel ratio of the air-fuel mixture at the set value, thus effectively reducing the torque shock after acceleration, while improving drivability and emission performance. It is to improve.

(Means for Solving the Problems) In order to achieve the above-mentioned object, the solution means of the present invention detects a fuel supply means 9 for supplying fuel to the engine 1 and an acceleration of the engine 1 as shown in FIG. Acceleration detection means 30
When the acceleration of the engine 1 is equal to or higher than a set value, the fuel supply amount is increased, and when the acceleration of the engine 1 is less than the set value, the increased fuel is gradually decreased. The fuel amount increase control unit 31 for controlling the fuel supply unit 9 is provided to receive the output of the acceleration detection unit 30. The configuration is provided with a reduction ratio setting unit 32 that moderates the fuel reduction ratio.

(Operation) With the above configuration, in the present invention, the fuel supply means 9 is controlled by the fuel increase control means 31 to increase the fuel quantity to the engine 1 at the time of acceleration when the engine acceleration is equal to or higher than the set value. The output responsiveness of the engine 1 is improved, and the acceleration performance is improved.

After that, after the acceleration in which the engine acceleration becomes less than the set value, the fuel supply control means 31 controls the fuel supply means 9 to gradually reduce the increased fuel during acceleration, and the mixed fuel after the acceleration is mixed. The stability of the combustion state of the air is improved, and the torque shock after acceleration is effectively reduced.

At that time, the decrease ratio of the increased fuel is set by the decrease ratio setting means 32, and in the steady operation state where the acceleration is small, the decrease amount of the increased fuel is set so as to correspond quickly to the situation where the change in the intake air amount is small. , The air-fuel ratio overrich tendency is effectively suppressed, and the HC reduction effect and the like are well secured,
Emission performance is improved.

On the other hand, in the slow acceleration state where the acceleration is large, the decrease ratio of the increased fuel is set gently in response to the gradual increase in the intake air amount, so the over lean tendency of the air-fuel ratio is effectively suppressed, and the acceleration to the acceleration is reduced. (Rotation) is prevented, and drivability is improved.

(Embodiment) An embodiment of the present invention will be described below with reference to the drawings starting from FIG.

FIG. 2 shows the overall configuration of a fuel supply control device for an engine according to the present invention, where 1 is an engine, 2 is a combustion chamber having a variable volume formed by a piston 4 slidably fitted in a cylinder 3 of the engine 1. 5, one end communicates with the atmosphere through an air cleaner 6, the other end opens into the combustion chamber 2 to supply intake air to the engine 1, and 7 opens into the combustion chamber 2 at one end. The other end is an exhaust passage for releasing exhaust gas to the atmosphere, and a throttle valve 8 for controlling the intake air amount is provided in the middle of the intake passage 5, and fuel is supplied downstream of the throttle valve 8 to the engine. 1 and a fuel injection valve 9 as a fuel supply means for injecting and supplying the fuel to the combustion chamber 1.
10 is an exhaust valve at the opening of the exhaust passage 7 to the combustion chamber 2.
11 are arranged respectively. Further, a spark plug 12 for igniting the air-fuel mixture in the combustion chamber 2 is arranged at the top of the combustion chamber 2. In the figure, 13 is a catalyst device provided in the exhaust passage 7.

Further, 15 is an air flow sensor for detecting the intake air amount on the upstream side of the throttle valve 8 in the intake passage 5, and 16 is the throttle valve 8
Throttle valve opening sensor that detects the opening of the engine, 17 is a cooling water temperature sensor that detects the engine cooling water temperature, and 18 is an air-fuel ratio sensor that detects the air-fuel ratio of the air-fuel mixture based on the oxygen concentration component in the exhaust gas of the exhaust passage 7. , 19 are engine speed sensors for detecting engine speed, and respective detection signals of the five sensors 15-19 are inputted to a controller 25 having a built-in CPU, RAM, etc. The injection valve 9 and the spark plug 12 are each controlled, and the fuel injection amount and ignition timing to the engine 1 and the ignition timing of the air-fuel mixture are adjusted and controlled.

Next, the operation control of the fuel injection valve 9 by the controller 25 will be described based on the control flow of FIG. After starting, the engine speed with reading free from speed sensor 19 in step S _1, each intake air quantity Qa and a throttle valve opening sensor from air flow sensor 15 in step S ₂ and S ₃
After is loaded the throttle valve opening degree from 16, the engine 1 based at Step S ₄ to the temporal change of the throttle valve opening
Thereby calculating the acceleration A of the basic fuel injection quantity To from the fuel injection valve 9 in accordance with the intake air quantity Qa at step S ₅
Is calculated.

Then, in step S ₆ , the engine acceleration A is compared with the set value b corresponding to the acceleration operation, and if YES when A ≧ b, the acceleration as the increased fuel during acceleration is performed in step S _7. a correction amount Ta is calculated to increase in accordance with increase in engine acceleration a, then initially set to zero value the value of the acceleration attenuation Td after the acceleration because the vehicle is accelerating at step S _8,
Immediately proceed to step S ₁₆ .

On the other hand, if after acceleration A <b in step S _6, the process proceeds to step S ₉ and subsequent to performing the reduction control of the bulking fuel during acceleration, at the end of the first reduction control bulking fuel in said step S ₉ In order to determine whether or not it is, the value of the acceleration correction amount Ta is set to the acceleration attenuation amount Td.
The comparison values and magnitudes, Ta ≠ whereas in the case of a reduction control in NO of Td performs reduction control for increasing the fuel proceeds to subsequent step S _10, Ta = immediately when the reduction control of YES in Td end step S Proceed to ₁₆ .

Then, in the decrease control of the increased fuel, first in step S ₁₀ , the engine acceleration A is recalculated based on the temporal change of the throttle valve opening, and in step S ₁₁ , the value of the engine acceleration A is set from the set value b above. Is compared with the predetermined value a, which is a small value, and if A <a (in the case of NO), it is determined that the engine is in steady operation and compared with the acceleration damping amount Td in order to quickly reduce the increased fuel in step S _12. While adding a relatively small value ΔTd ₁ ,
If YES in the case of A ≧ a, it is determined that the vehicle is accelerating slowly, and the acceleration damping amount Td is a minute value ΔTd smaller than the minute value ΔTd _{1 in} order to gradually decrease the increased fuel in step S _{13. 2} (ΔTd
₂ Add <ΔTd ₁ ).

Thereafter, the acceleration correction amount T a value of the addition attenuation Td in Step S ₁₄
The value of a is compared with the value of a, and if Td ≧ Ta is YES, the value of the acceleration attenuation amount Td is corrected to be equal to the acceleration correction value Ta in step S ₁₅ in order to prevent the reduction of less than the basic injection amount Ta.

And thus the basic injection quantity To, after setting the acceleration correction quantity Ta and the acceleration attenuation Td, the final fuel injection by respective set values To, Ta, ineffective injection time Td and vehicle battery Tv in Step S ₁₆ the amount T by calculating based on the following equation T = to + Ta-Td + Tv, the fuel injection valve 9 so as to be the final fuel injection amount T operation control is made in step S _17, the process returns.

Therefore, in the control flow of FIG. 3 above, step S ₄
Thus, the acceleration detecting means 30 is configured to detect the acceleration A of the engine 1 based on the temporal change of the opening degree of the throttle valve 8. Moreover, Step S ₆ ~S _12, S ₁₄ ~S
₁₇ , the output of the acceleration detecting means 30 is received, and when the engine acceleration A is accelerated to a set value b or more, the basic fuel injection amount is increased.
The acceleration correction amount Ta is added to To to increase the final fuel injection amount T to the engine 1. After that, when the engine acceleration A becomes less than the set value b, the acceleration attenuation amount Td is set to a minute value ΔTd. _The fuel amount increase control means 31 is configured so that the acceleration correction value Ta (increased fuel amount) is gradually decreased by the acceleration attenuation amount Td by gradually increasing the amount by 1. Furthermore, steps S ₁₁ and S ₁₃
Therefore, when the output of the acceleration detection means 30 is received and the acceleration correction amount Ta is controlled to decrease by the fuel increase control means 31,
When the engine acceleration A is extremely small value a or more, the increment of the acceleration damping amount Td is switched from the small value ΔTd ₁ to the extremely small value Td _2, and the increase rate of the acceleration damping amount Td is lowered by that amount to accelerate. The decrease rate setting means 32 is configured to moderate the decrease rate of the correction amount Ta.

Therefore, in the above embodiment, as shown in FIG. 4 (a), when the rate of change of the throttle valve opening 8 (the acceleration of the engine) is equal to or greater than the set value b, the fuel increase control means is operated.
Since the fuel injection valve 9 is controlled by 31 and the final fuel injection amount T to the engine 1 is increased by the acceleration correction amount Ta in addition to the basic injection amount To, the responsiveness of the engine output becomes high. Acceleration performance is improved.

Then, after that, after the acceleration in which the engine acceleration A drops below the set value b, the acceleration A is further reduced to a predetermined value a (a <b).
During steady-state operation below, the intake air amount changes little, but the acceleration attenuation amount Td gradually increases at a relatively large small value ΔTd ₁ , and the acceleration correction amount Ta (increased fuel) gradually increases by a small value ΔTd. _By relatively large decrease by ₁ , and quickly returning to the normal value of the basic injection amount To, the torque shock is effectively suppressed by the tailing of the acceleration correction amount Ta, and the air-fuel ratio of the air-fuel mixture does not become overrich. The HC reduction effect and the like are favorably maintained, and the emission performance is improved.

On the other hand, as shown in FIG. 4 (b), after the acceleration, in the state of gentle acceleration in which the engine acceleration A is equal to or higher than the predetermined value a, the intake air amount gradually increases, but the acceleration damping amount Td The increment is decreased by the decrease rate setting means 32 by the above-mentioned minute value ΔTd.
_The value is changed from ₁ to a very small value ΔTd ₂ (ΔTd ₂ <ΔTd ₁ ), and the acceleration correction amount Ta gradually decreases by this very small value ΔTd _2, so the torque due to the tailing operation of this acceleration correction amount Ta. While the shock is effectively suppressed, the intake air amount Qa
And the final fuel injection amount To correspond favorably to each other, and the over lean of the air-fuel ratio is effectively prevented. As a result, acceleration hedging is prevented, and drivability is improved. Therefore, during steady operation or slow acceleration after acceleration, it is possible to effectively suppress the torque shock and maintain the air-fuel ratio of the air-fuel mixture at the set air-fuel ratio satisfactorily to improve emission performance and drivability. it can.

In the above embodiment, when the engine acceleration A is in the slow acceleration of the predetermined value a or more during the decrease control of the increased fuel, the rate of decrease of the acceleration correction amount Ta is made gentle (the increment of the acceleration attenuation amount Td is made small). However, in addition to this, a large number of reference values for determination such as the predetermined value a may be set, and the reduction rate may be set in multiple stages. The point is that the greater the engine acceleration A, the slower the reduction rate. .

(Effects of the Invention) As described above, according to the present invention, after the acceleration operation in which the fuel amount is increased, the decreasing rate of the increased fuel is gradually tailed as the subsequent acceleration increases, and Since the air-fuel ratio of the air-fuel mixture is always kept at a favorable value, it is possible to improve emission performance and drivability while effectively suppressing torque shock after acceleration.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of the present invention. 2 to 4 show an embodiment of the present invention, FIG. 2 is an overall schematic configuration diagram, FIG. 3 is a flow chart showing the operation of the controller, and FIGS. FIG. 1 ... Engine, 8 ... Throttle valve, 9 ... Fuel injection valve, 25 ... Controller, 30 ... Acceleration detecting means, 31 ...
… Fuel increase control means, 32 …… Decrease rate setting means.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroto Yama Prefecture 3-3 Shinchi, Fuchu-cho, Aki-gun, Hiroshima Mazda Co., Ltd. (56) References JP-A-58-67935 (JP, A) JP-A-58 -144639 (JP, A) JP-A-58-220931 (JP, A) JP-B 1-37583 (JP, B2) JP-B 2-51052 (JP, B2) JP-B 5-9620 (JP, B2) )

Claims (1)

[Claims] 1. A fuel supply means for supplying fuel to an engine, an acceleration detection means for detecting an acceleration of the engine, and an output of the acceleration detection means. When the acceleration of the engine is equal to or higher than a set value, the fuel supply amount is increased. However, when the acceleration of the engine becomes less than the set value, the fuel increase control means for controlling the fuel supply means to gradually decrease the increased fuel and the output of the acceleration detection means, and the fuel increase control. A fuel supply control device for an engine, comprising: a reduction rate setting means that moderates a reduction rate of the increased fuel as the acceleration increases during the reduction control of the increased fuel by the means.