JPS6043135A - Fuel supply rate controlling method for internal- combustion engine - Google Patents

Abstract

PURPOSE:To prevent uncomfortable shock caused at the time of accelerating or decelerating an engine and to improve the accelerating and decelerating performance of the engine, by varying the fuel supply rate with a proper primary delay to the depression of an accelerator pedal. CONSTITUTION:A requisite air-flow rate QA is estimated from the engine speed and the depth of depression of an accelerator pedal, and the fuel supply rate is varied to a value meeting the above requisite air-flow rate QA with a proper primary delay to the depression of the accelerator pedal. By employing such a method, it is enabled to prevent uncomfortable shock caused at the time of accelerating or decelerating an engine and to improve the accelerating and decelerating performance of the engine.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for controlling the amount of fuel supplied to an internal combustion engine.

In general, in internal combustion engines, it is known that even if the throttle valve is fully open or fully closed at time zero, the flow rate of air sucked into the cylinder changes with a first-order delay t'L having a certain time constant. . To explain this point in detail, for example, as shown in FIG. 1, the air flow rate at the throttle valve 1 is QAv, and the air flow rate at the manifold 2 is QAm.

Flow rate of air sucked into cylinder 3'i = QA E
, the volume of manifold 2 is fVm, the absolute pressure inside manifold 2 is Pm, the volume of cylinder 3 is Vc, and the engine speed is iN. Considering the case of a 4-cylinder engine, (23°C, 760 +++mTrS') U becomes. Also, QAn]=ρVm=KPmVm i . Also, QAm = QAv −QAi ・= −・・−−(3
). Therefore, fl), (2+, from equation (3), and from this, the absolute pressure Pm has a time constant of □ even if the air flow if QAv changes at a time of zero m30~\'cN order lag Therefore, the flow rate QA (QA E ) of air entering the cylinder 3 also changes in inverse proportion to the absolute pressure Pm with a first-order lag.

Therefore, for example, as one of the conventional fuel supply amount control methods, the method of immediately changing the fuel injection amount of the injector in response to the change in the amount of depression of the accelerator pedal VC as shown by the dotted line in FIG. There was a problem in that the air-fuel ratio and torque sometimes changed suddenly, causing unpleasant shocks. On the other hand, as another method, the fuel injection amount of the injector is changed in inverse proportion to the absolute pressure Pm in the manifold I, as shown by the dotted line in Fig. 2. There was a problem that a time lag occurred and acceleration/deceleration performance was poor.

In view of the above problems, the present invention predicts the required air flow rate from the amount of depression of the accelerator pedal and the engine rotational speed, and calculates the required air flow rate while maintaining a suitable first-order delay with respect to the amount of depression of the accelerator pedal. To provide a fuel supply amount control method that can prevent unpleasant shocks during acceleration and deceleration and improve acceleration and deceleration performance by changing the fuel supply amount at a value corresponding to Although it is a thing,
This will be explained below based on an embodiment shown in FIGS. 3 and 141. FIG. 3 shows the control/ξ turn of the method of the present invention, for example, from point A (QA+, QFI) to 8
When the driver depresses the accelerator pedal at point (QA, 2 + Q P2) i, various sensors detect the pedal depression and the engine speed at point A, and based on these values, calculate the required air flow rate at point 8. The air flow rate QA2 is predetermined, and then the fuel is supplied fA-, QF (injector fuel injection amount). When expressed as a formula, it is as follows.

QFn=(QF2−QF+)(1r+QF+CO
<r<1')...<6) However, nl'j: Fubutetsu times. Therefore, the change in the fuel supply i Q F is as shown by the dotted line diagram in FIG. If the value of the constant r is changed, the change curve of the fuel supply amount QF also changes, so the air-fuel ratio can be set arbitrarily. Thus, by appropriately selecting the change curve of the fuel supply amount QF, unpleasant shocks during acceleration and deceleration can be prevented. 1, and acceleration/deceleration performance can be improved.

As described above, according to the fuel supply amount control method according to the present invention, unpleasant shocks at the time of deceleration can be prevented and
11 has a practically important advantage of improving deceleration performance.

[Brief explanation of the drawing]

Figure 1 is a schematic diagram showing the change in the amount of air from the manifold to the cylinder (Ml''L) depending on the position, Figure 2 is a graph showing the change characteristics of the fuel supply amount by a conventional fuel supply amount control device, and Figure 3 is A diagram showing a control pattern of an embodiment of the fuel supply control method according to the present invention, Figure 4 is a diagram showing the change sound 1 (1 mo) of the fuel supply amount according to the above embodiment. QA... Nitrogen mud Mouse, Q To'...Fuel supply lid. Fig. 1 2 Fig. 2 Fig. 3 Fig. 4.

Claims (1)

[Claims] The required air flow rate is predicted from the accelerator pedal depression amount and the engine speed, and the total fuel supply amount is changed from an excessive first-order delay n to a value corresponding to the required air flow rate by adding λ・1 to the accelerator pedal depression. A fuel supply amount control method for an internal combustion engine that