JPH0270949A - Electronic control fuel injection device for internal combustion engine - Google Patents

Abstract

PURPOSE:To prevent an air-fuel ratio from entering a lean region when an engine speed is sharply reduced due to an increase in a load by a method wherein even when the opening of a throttle valve is kept at an approximately specified value, when a change in the engine speed is high, correction control of a wall flow is performed. CONSTITUTION:Based on a state amount of intake air detected by an intake air state amount detecting means, a fundamental fuel injection amount is computed by a fundamental fuel injection computing means and corrected by a correction means to compute a fuel injection amount. By means of signals from a throttle valve opening change amount detecting means and an engine speed change amount detecting means, it is decided by a deciding means that acceleration occurs, when a change amount exceeds or is below a negative given value, it is decided thereby that deceleration occurs, when a change amount of the engine speed exceeds or is below a positive given value except during decision of acceleration and deceleration, it is decided thereby that transition occurs. During decision of acceleration, an increase amount is corrected by a correction means, during decision of deceleration, a decrease amount is corrected, and during decision of transition, correction is made in an opposite direction to the change direction of the engine speed. This constitution enables prevention of an air-fuel ratio from entering a lean region when the engine speed is sharply reduced due to an increase in a load.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an electronically controlled fuel injection device for an internal combustion engine.
In particular, it relates to a device having a wall flow correction control function during acceleration and deceleration.

<Prior art> Conventionally, in an electronically controlled fuel injection system for an internal combustion engine, the intake air flow rate Q is detected as the state quantity of the intake air, and from this and the engine speed N, the basic fuel injection amount Tp = -Q /N(K
Alternatively, the intake pressure (intake negative pressure) PB is detected as the state quantity of the intake air, and based on this, the basic fuel injection ITp-K・η7・PB- is calculated by A (K is a constant). , η9 is the volumetric efficiency, and KTA is the intake temperature correction coefficient). Note that the method based on the intake air flow rate Q is called L-JETRO, and the method based on intake pressure PB is called D-JETRO. Then, the final fuel injection amount Ti=Tp is corrected by the air-fuel ratio feedback correction coefficient α, various correction coefficients C0EF based on water temperature, etc., and the voltage correction numerator s based on the battery voltage.
- Calculate α・C0EF+Ts.

In addition, the various correction coefficients C0EF (-t+Ktw+K
wF+...) is the water temperature correction coefficient? In addition to W, etc., there is a wall flow correction coefficient Kwr, which determines acceleration/deceleration based on the amount of change in throttle valve opening, etc. When determining acceleration, some of the fuel becomes a wall flow and the arrival of the fuel is delayed, so the fuel The injection amount is corrected to increase, and when determining deceleration, the fuel injection amount is corrected to decrease in order to avoid the influence of the supply of fuel that was previously injected and became a wall flow.
214629, JP-A-58-220931, etc.).

Then, at a predetermined timing synchronized with the engine rotation, a drive pulse signal having a pulse width corresponding to the fuel injection amount Ti is outputted to the electromagnetic fuel injection valve, thereby injecting and supplying fuel to the engine.

<Problems to be Solved by the Invention> However, when acceleration/deceleration is determined based on the amount of change in throttle valve opening as in the past and wall flow correction control is performed at the time of acceleration/deceleration determination, the following problems arise. there were.

That is, referring to Fig. 7, when the throttle valve opening TVO is almost constant but the engine speed N decreases significantly due to an increase in load, such as when the clutch is engaged during a gear change, the air-fuel ratio increases. Unify into one.

This means that when the opening area of the throttle valve section is A and the engine speed is N, the basic volumetric efficiency is determined for the value of A/N as shown in Figure 8. When the amount of intake air decreases, there is a step difference in the amount of intake air by ΔN, so a step difference in the equilibrium adhesion amount occurs, which requires correction. However, since the presence or absence of correction is determined based on the amount of change in throttle valve opening, correction cannot be made and the air-fuel ratio becomes lean.

The present invention aims to solve these conventional problems.

Means for Solving the Problems> Therefore, as shown in FIG. In an electronic side 'a fuel injection device for an internal combustion engine, the electronic side 'a fuel injection device for an internal combustion engine includes a basic fuel injection amount calculation means for calculating a basic fuel injection amount based on the basic fuel injection amount, and a correction means for calculating the fuel injection amount by correcting the basic fuel injection amount, A throttle valve opening change amount detection means for detecting a change amount in the throttle valve opening degree, an engine rotation speed change amount detection means for detecting a change amount in the engine speed, and a predetermined value for which the change amount in the throttle valve opening degree is positive. Acceleration determining means determines acceleration in the above cases, deceleration determining means determines deceleration when the amount of change in throttle valve opening is less than a predetermined negative value, and change in engine speed other than when determining acceleration/deceleration. Transient determination means for determining a transient state when the amount of fuel injection is greater than or equal to a positive predetermined value or less than or equal to a negative predetermined value; The present invention is configured to include a deceleration reduction correction means for reducing the fuel injection amount at the time of determination, and a transient correction means for correcting the fuel injection amount in the opposite direction to the change direction of the engine speed at the time of transient determination.

In the above configuration, even if the throttle valve opening is almost constant, if the engine speed changes significantly, it is determined to be transient, and the fuel injection amount is changed in the opposite direction to the engine speed change direction. It is corrected to Therefore, for example, when the throttle valve opening is almost constant but the engine speed drops significantly due to an increase in load, such as when the clutch is engaged during a gear change, an increase correction is made and the air-fuel ratio is lean. It is possible to prevent

<Example> An example of the present invention (in the case of D-JETRO) will be described below.

In FIG. 2, an engine 1 is connected to an air cleaner 2 through an intake duct 3. Throttle valve of throttle chamber 4 5.
Air is drawn in via the intake manifold 6.

A fuel injection valve 7 is provided in each branch of the intake manifold 6 for each cylinder. The fuel injection valve 7 is an electromagnetic fuel injection valve whose solenoid is energized to open the valve, and whose energization is stopped to close the valve.The fuel injection valve 7 is energized by a drive pulse signal from a control unit 9 to be described later to open the valve, and is opened by a fuel pump (not shown). Fuel is pressure-fed and adjusted to a predetermined pressure by a pressure regulator, and then injected.

An ignition plug 8 is provided in the combustion chamber of the engine 1, which ignites a spark to ignite and burn the air-fuel mixture.

The control unit 9 includes a CPU and a ROM.

Equipped with a microcomputer that includes a RAM, an A/D converter, and an input/output interface, it performs arithmetic processing based on input signals from various sensors, and controls the fuel injection valve 7.
and controls the operation of the spark plug 8.

However, below, only the control of the fuel injection amount by the fuel injection valve 7 will be explained.

Among the various sensors described above, an intake pressure sensor 10 as an intake air state quantity detection means is provided in the intake manifold 6, and detects the intake pressure (intake negative pressure) PB.

Further, an intake temperature sensor 11 is provided, and the intake temperature Ta
Detect.

Further, a crank angle sensor 12 is provided, and for example, in the case of a 4-cylinder engine, a reference signal REF is provided for each crank angle of 180°.
and a unit signal PO3 for each crank angle of 1 to 2 degrees. The engine speed N can be calculated from these signals.

Further, the throttle valve 5 is provided with a potentiometer-type throttle sensor 13, and the throttle valve opening degree TV
Detect O.

Further, an 02 sensor 14 is provided in the exhaust manifold of the engine 1, and detects whether the air-fuel ratio is rich or lean via the oxygen concentration in the exhaust gas.

Further, a water temperature sensor 15 is provided facing the water jacket of the engine 1 to detect the cooling water temperature Tw.

Here, a microcomputer (CPU) built into the control unit 9 performs arithmetic processing and controls the fuel injection amount according to a program on a ROM shown as flowcharts in FIGS. 3 to 5.

Next, the state of the arithmetic processing of the microcomputer in the control unit 9 will be explained with reference to the flowcharts shown in FIGS. 3 to 5.

FIG. 3 is a fuel injection amount Ti calculation routine.

In step 1 (denoted as Sl in the figure; the same applies hereinafter), the intake pressure PB detected based on the signal from the intake pressure sensor 10 is read as the state quantity of intake air. However, this intake pressure PB is averaged.

In step 2, based on the intake pressure PB, the basic fuel injection amount'
rp=K·η9·PBL-KyA (K is a constant, η9 is volumetric efficiency, and KTA is an intake air temperature correction coefficient). This part corresponds to the basic fuel injection amount calculation means.

In step 3, the fuel injection amount Ti=Tp・α・C0EF
+Ts is calculated. α is an air-fuel ratio feedback correction coefficient, C0EF is various correction coefficients, and Ts is a voltage correction factor.

This part corresponds to the correction means.

Here, various correction coefficients C0EF are calculated by the following formulas. ) (tw is the water temperature correction coefficient, KwF is the wall flow correction coefficient.

COE F "" 1 + Ktw+ Kwr+-The wall flow correction coefficient 8F is set by the routines shown in FIGS. 4 and 5, which will be described later. It functions as a means and a transient correction means.

When the fuel injection amount Ti is calculated in this way, a drive pulse signal with a pulse width corresponding to this Ti is output to the fuel injection valve 7 at a predetermined timing synchronized with the engine rotation.
Fuel injection takes place.

FIG. 4 shows an acceleration/deceleration and transient determination routine, which is executed every unit time (for example, 10 m5).

In step 11, the throttle valve opening TVO detected by the throttle sensor 13 and the engine speed N calculated based on the signal from the crank angle sensor 12 are read.

In step 12, the amount of change in the detected throttle valve opening TVO with respect to the previous value TVO0, 4 is ΔTVO=TVO−
Calculate TVO014 and also calculate the detected engine speed N
Previous value N. Amount of change ΔN with respect to I4 = N N
Calculate 0t a.

In step 13, TVO and N are substituted into TV 00ta and N0ta, respectively, for the next calculation.

Here, steps 11 to 13 correspond to the throttle valve opening change amount detection means and the engine rotational speed change amount detection means.

In step 14, ΔTVO is set to a positive predetermined value +A (for example, +
〇, 96 degrees), and when ΔTVO≧+A, it is determined that acceleration is occurring, and the process proceeds to step 18, where an increase flag Fl is set. This part corresponds to the acceleration determining means.

In step 15, ΔTVO is set to a negative predetermined value -A (for example -
0.96 deg), and when ΔTVO≦−A, it is determined that deceleration is occurring, and the process proceeds to step 19, where a weight loss flag F2 is set. This part corresponds to deceleration determining means.

When determining acceleration/deceleration, the process proceeds to step 16 and subsequent steps.

In step 16, ΔN is compared with a positive predetermined value B, and ΔN
When ≧10B, it is determined that there is a transition (rotation angle, rise), and the process proceeds to step 19, where a weight loss flag F2 is set.

However, it is actually almost impossible for the engine speed N to suddenly increase when the throttle valve opening TVO is approximately constant.

In step 17, ΔN is compared with a negative predetermined value -B, and ΔN
When ≦-B, it is determined that there is a transition (sudden decline in rotation), and the process proceeds to step 18, where an increase flag F1 is set.

Here, steps 16 and 17 correspond to the transient determination means.

If it is not acceleration/deceleration and is not transient, step 20
Then, both the increase flag F1 and the decrease flag F2 are reset.

FIG. 5 shows a wall flow correction coefficient Kwr setting routine.

In step 21, the value of the increase flag F1 is determined, and F1=
In the case of 1, proceed to step 23 and calculate the wall flow correction coefficient Kw.
Set F to an appropriate positive value. This portion corresponds to the acceleration increase correction means and the transient correction means.

In step 22, the value of the weight loss flag F2 is determined, and F2=
If it is 1, proceed to step 24 and set the wall flow correction coefficient as %.
, IF are set to appropriate negative values. This portion corresponds to the deceleration reduction correction means and the transient correction means.

If Fl=O, F2=O, proceed to step 25,
Wall flow correction coefficient K. The value of the wall flow correction coefficient KWF itself is determined using parameters such as the amount of change ΔTVO in the throttle valve opening, the water temperature Tw, the engine speed N, and the basic fuel injection amount Tp. get closer to

With this wall flow correction control, for example, as shown in Fig. 6, when the clutch is engaged during a gear change, the engine speed N decreases due to an increase in load while the throttle valve opening TVO remains almost constant. When the air-fuel ratio decreases significantly, the wall flow correction coefficient KWF is set to an appropriate positive value, and an increase correction is performed thereby to prevent the air-fuel ratio from becoming lean and to make it appropriate.

Note that although the example of D-JETRO has been described above, it is of course applicable to L-JETRO as well.

<Effects of the Invention> As explained above, according to the present invention, even if the throttle valve opening is approximately constant, wall flow correction control is performed when the engine speed changes significantly. For example, when the engine speed drops significantly due to an increase in load even though the throttle valve opening is almost constant, such as when the clutch is engaged during a gear change, the increase correction prevents the air-fuel ratio from becoming lean. This improves air-fuel ratio control during sudden changes in rotation, and also improves emissions, fuel efficiency, and drivability.

[Brief explanation of the drawing]

Fig. 1 is a functional block diagram showing the configuration of the present invention, Fig. 2 is a system diagram of an internal combustion engine showing an embodiment of the invention, Figs. 3 to 5 are flow charts showing the contents of calculation processing, and Fig. 6 is a control characteristic diagram according to the present invention, and FIGS. 7 and 8 are diagrams showing conventional problems. 1... Engine temperature sensor Throttle sensor 5... Throttle valve 7... Fuel injection valve 10... Intake pressure sensor 12... Crank angle sensor 6... Intake 7 9. ...Control 11...Intake 13...Slot Patent applicant: Japan Electronics Co., Ltd. Agent: Patent attorney Fujio Yu Sasashima 3 Figure 5

Claims (1)

[Claims] an intake air state quantity detection means for detecting a state quantity of intake air taken into the engine; a basic fuel injection quantity calculation means for computing a basic fuel injection quantity based on the state quantity of the intake air; An electronically controlled fuel injection device for an internal combustion engine, comprising a correction means for correcting and calculating a fuel injection amount,
A throttle valve opening change amount detection means for detecting a change amount in the throttle valve opening degree, an engine rotation speed change amount detection means for detecting a change amount in the engine speed, and a predetermined value for which the change amount in the throttle valve opening degree is positive. Acceleration determining means determines acceleration in the above cases, deceleration determining means determines deceleration when the amount of change in throttle valve opening is less than a predetermined negative value, and change in engine speed other than when determining acceleration/deceleration. Transient determination means for determining a transient state when the amount of fuel injection is greater than or equal to a positive predetermined value or less than or equal to a negative predetermined value; An internal combustion engine characterized by comprising: a deceleration reduction correction means for reducing the fuel injection amount at the time of determination, and a transient correction means for correcting the fuel injection amount in the opposite direction to the change direction of the engine rotation speed at the time of transient determination. Electronically controlled fuel injection device.