KR100264553B1 - Injection rate calculation method during fuel reinjecting - Google Patents

Abstract

PURPOSE: A fuel injection amount calculating method in case of fuel re-injection is provided to determine an injection amount to control on the basis of comparison an engine rpm reduction amount and an opening degree of a throttle valve with reference values by employing a variable value corresponding to the engine rpm change amount and the opening degree of the throttle valve, thereby preventing the engine stop even in case of rapid reduction of the engine rpm. CONSTITUTION: A fuel injection amount calculating method in case of fuel re-injection includes the steps of judging a fuel shutoff state according to an injection signal of an electronic control unit(S2), judging a fuel re-injection state according to the injection signal in case of fuel shut-off state(S3), determining whether a reduction amount of an engine rpm is larger than a predetermined value(A) in case of fuel re-injection state(S4), determining whether a value of a throttle valve position sensor is larger than a predetermined value(B)(S5), determining a current injection amount with a value obtained by multiplying a first variable(D) corresponding to the engine rpm change amount and an opening degree of a throttle valve with an injection amount before a cycle, if the throttle valve position sensor value is smaller than the predetermined value(S6), and determining the current injection amount with a value obtained by multiplying a second variable(C) corresponding to an engine rpm change amount and an opening degree of a throttle valve with the injection amount before a cycle, if the throttle valve position sensor value is larger than the predetermined value(S7).

Description

How to calculate the injection volume when reinjecting fuel

1 is a flowchart illustrating a method for calculating injection amount upon re-injection of fuel according to an embodiment of the present invention.

The present invention relates to a method for calculating an injection amount applied to an electronically controlled fuel injection device of a vehicle. More specifically, when the fuel injection device is in a fuel injection cutoff state due to rapid deceleration or engine overheating, etc. In addition, the present invention relates to a method of calculating an injection amount capable of preventing engine stall and improving acceleration by calculating and injecting fuel injection amount upon re-injection according to a reduction in engine speed and a position of a throttle valve.

According to the conventional fuel injection control technology, if the fuel cut-off state is caused due to sudden deceleration or engine overheating, and the engine state does not satisfy the fuel cut-off condition, the fuel injection state is changed to a fuel re-wet state ( The amount of injection in this fuel re-injection state is determined to a predefined value regardless of the state of the engine.

However, when the engine revolution (RPM: Revolution Per Minute) decreases sharply when the fuel is re-injected, engine stoppage may occur, and the acceleration performance is deteriorated when the driver suddenly presses the accelerator pedal due to the willingness to accelerate. There is a problem that the operability is reduced.

Therefore, an object of the present invention is to solve the conventional technical problems as described above, and to be injected by calculating the injection amount according to the reduction amount of the engine speed and the position of the throttle valve when transitioning from the fuel cut state to the fuel re-injection state. Accordingly, the present invention provides a method for calculating the injection amount during re-injection which prevents engine stoppage even when the engine speed is rapidly decreased and improves operability by injecting fuel according to the driver's willingness to accelerate.

As a means for achieving the above object, the configuration of the injection amount calculation method according to the present invention comprises: a first step of determining whether the fuel is shut off from the injection signal of the electronic control unit; A second step of determining whether the fuel is re-injected from the injection signal when the fuel is shut off in the first step; A third step of determining whether the reduction amount of the engine speed is greater than a predetermined value (A) when in the re-injection state in the second step; A fourth step of determining whether a value of the throttle valve position sensor is larger than a predetermined value (B) when the reduction amount of the engine speed is smaller than a predetermined value (A) in the third step; When the value of the throttle valve position sensor in the fourth step is smaller than the predetermined value (B), the current injection amount and the first variable (D) corresponding to the change amount of the engine speed and the throttle valve opening degree and the injection amount before one cycle A fifth step of determining by a value obtained by multiplying; When the engine speed reduction amount is greater than the predetermined value A in the third step or the value of the throttle valve position sensor is larger than the predetermined value B in the fourth step, the current injection amount and the throttle of the engine speed And a sixth step of determining the value obtained by multiplying the second variable C corresponding to the valve opening degree by the injection amount one cycle ago.

The process from the first to the sixth step is repeated at a predetermined time period, and each time the first variable (D) and the second variable (D) are the change amount of the engine speed and the throttle valve opening degree at that time. Is determined correspondingly.

Hereinafter, with reference to the accompanying drawings will be described a preferred embodiment of the present invention.

1 is a flowchart illustrating a method for calculating injection amount upon re-injection of fuel according to an embodiment of the present invention.

When the battery power is supplied to the electronic control unit, the operation of the injection amount calculation method according to the embodiment of the present invention is started (S1).

First, the injection signal output from the electronic control unit to the injector is checked, and it is determined whether the fuel is shut off from the injection signal (S2). In the case of the fuel cutoff state in this step 52, it is determined whether the vehicle has entered the re-injection state from the injection signal (S3). If the fuel is not in the fuel cut-off state or the re-injection state in the two steps (S2, S3), the step is jumped, and subsequent operations are not immediately performed (S8).

When entering the re-injection state in the step (S3), it is determined whether the reduction amount of the engine speed (RPM) detected from the crank angle sensor is greater than the predetermined value (A) (S4). Here, the predetermined value A is a reference value of the engine speed reduction amount for determining the injection amount during re-injection.

When the engine speed reduction amount is smaller than the predetermined value A in the step S4, it is determined whether the output value of the throttle valve position sensor is larger than the this value B (S5). Here, the predetermined value B is a reference value of the opening amount of the throttle valve for determining the injection amount during re-injection.

If the output value of the throttle valve position sensor in the step (S5) is less than the predetermined value (B), the injection amount to be controlled is determined to be a value obtained by multiplying the injection amount (P0) and the first variable (D) before one cycle ( S6). Here, the first variable D is a value determined corresponding to the current engine speed change amount and the opening degree of the throttle valve.

When the engine speed reduction amount is greater than the predetermined value A in the step S4 or the output value of the throttle valve position sensor is larger than the predetermined value B in the step S5, the injection amount to be controlled is one injection amount before one cycle ( To determine the value obtained by multiplying P0) and the second variable (C) (S7). Here, the second variable C is a value determined corresponding to the current engine speed change amount and the opening degree of the throttle valve.

When the execution of the step (S6) or step (S7) is finished, the injection amount calculation method is completed (S8).

On the other hand, the operation from step S1 to step S8 is repeatedly performed in a predetermined time period, each time the first variable (D) and the second variable (C) is the engine speed change amount and throttle at that time It is determined corresponding to the opening degree of the valve.

As described above, according to the exemplary embodiment of the present invention, the amount of engine speed to be controlled is compared to a predetermined reference value to determine the injection amount to be controlled. By applying a variable value corresponding to the opening degree, it is possible to prevent the engine from occurring even when the engine speed is drastically reduced.

In addition, it is possible to improve the operability by determining the injection amount in accordance with the driver's acceleration will.

Claims (2)

A first step of determining whether the fuel is shut off from the injection signal of the electronic control unit; A second step of determining whether the fuel is re-injected from the injection signal when the fuel is shut off in the first step; A third step of determining whether the reduction amount of the engine speed is greater than a predetermined value (A) when in the re-injection state in the second step; A fourth step of determining whether a value of the throttle valve position sensor is larger than a predetermined value (B) when the reduction amount of the engine speed is smaller than a predetermined value (A) in the third step; When the value of the throttle valve position sensor in the fourth step is smaller than the predetermined value (B), the current injection amount and the first variable (D) corresponding to the change amount of the engine speed and the throttle valve opening degree and the injection amount before one cycle A fifth step of determining by a value obtained by multiplying; When the engine speed reduction amount is greater than the predetermined value A in the third step or the value of the throttle valve position sensor is larger than the predetermined value B in the fourth step, the current injection amount and the throttle of the engine speed And a sixth step of determining the value obtained by multiplying the second variable (C) corresponding to the valve opening degree by the injection amount before one cycle. The method of claim 1, wherein the first to sixth steps are repeated at predetermined time intervals, and each time the first variable D and the second variable D are the engine speed at that time. Method for calculating the injection amount during the re-injection of fuel, characterized in that determined in accordance with the change amount of the throttle valve opening degree.