JPH06146994A - Throttle valve full open detector for internal combustion engine - Google Patents

Abstract

PURPOSE:To detect fully opened condition of a throttle valve at a high accuracy without using a dedicated position sensor. CONSTITUTION:The output signal of an air flow meter is read, and peak values QMAX, QMIN for upper and lower vibration based on inlet-air pulsation are detected (S1), to calculate amplitude DELTAQ=QMAX-QMIN (S2). The amplitude DELTAQ is compared with a judged value DELTASL (S4), and in a case of DELTAQ >= DELTASL, it is judged to be fully open on condition that this state is continued for a fixed number of times.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a throttle valve fully open detection device for an internal combustion engine.

[0002]

2. Description of the Related Art In controlling an internal combustion engine, it is important to detect whether or not a throttle valve is fully open. For this detection, conventionally, (1) a fully open position is detected using a potentiometer type position sensor whose output changes linearly with respect to the throttle valve opening, or (2) only a fully closed point and a fully opened point are detected. The switch was used to detect full open.

Further, as described in (3) Japanese Patent Publication No. 59-30897, the fuel injection amount from the fuel injection valve in the electronically controlled fuel injection device, more specifically, the intake air flow rate of the engine and the engine rotation speed. It has also been proposed to determine a state in which the pulse signal is a predetermined value or more as a full load state (full open state) based on the time width of the pulse signal applied to the fuel injection valve determined by the number.

[0004]

However, either of the above (1) or (2) requires a dedicated position sensor for detecting the throttle valve opening, and a signal input from the sensor is input to the control unit side. Since a circuit for use is required, the system cost is increased. Further, in the above (3), even if the throttle valve is fully opened, the fuel injection amount will decrease according to the decrease in the air density in the highlands, so the erroneous determination will be made in the highlands only based on the fuel injection amount. May occur and some correction is necessary.

The present invention has been made in view of such conventional problems, and an object thereof is to make it possible to detect the full opening of the throttle valve with high accuracy without requiring a dedicated position sensor.

[0006]

Therefore, according to the present invention, as shown in FIG. 1, an amplitude detecting means for detecting the amplitude of an output signal of an air flow meter for measuring an engine intake air flow rate,
A throttle valve full-open detection device for an internal combustion engine is configured by providing a full-open determination unit that determines that the throttle valve is fully open when the detected amplitude becomes equal to or greater than a predetermined value.

[0007]

With the intake pulsation of the engine, the output signal of the air flow meter for measuring the intake air flow rate of the engine oscillates, and its amplitude (difference between the upper and lower peak values) increases as the throttle valve opening increases. Not affected by density. FIG. 2 shows the relationship between the throttle valve opening and the air flow meter output (upper peak value, lower peak value, average value, amplitude).

Therefore, the amplitude of the signal from the air flow meter is detected, and when the detected amplitude exceeds a predetermined value, it is determined that the throttle valve is fully opened.

[0009]

EXAMPLE An example of the present invention will be described below. FIG. 3 is a system diagram of an internal combustion engine, in which an intake passage 2 of the engine 1 is provided with a throttle valve 3 interlocked with an accelerator pedal, and further an electromagnetic fuel injection valve 4 is provided downstream of a branch portion to each cylinder. It is provided. Incidentally, 5 is an intake valve, 6 is an exhaust valve, and 7 is an exhaust passage.

The control of fuel injection from the fuel injection valve 4 is performed based on the output from the control unit 8 incorporated in the microcomputer.
Various signals are input from the air flow meter 9 such as a hot wire type for measuring the intake air flow rate Q, a crank angle sensor 10 having a function of generating a reference crank angle signal and a unit crank angle signal, and the like.

Here, the detection of the full opening of the throttle valve 3 is performed by the microcomputer in the control unit 8 by executing the full opening detection routine shown in FIG. In step 1 (denoted as S1 in the figure; the same applies hereinafter), the output signal of the air flow meter 9 is read, and the peak values Q _MAX and Q _MIN above and below the vibration based on the intake pulsation are detected.

In step 2, the upper and lower peak values Q _MAX ,
As the difference Q _MIN, calculates the amplitude ΔQ = Q _{MA X} -Q _MIN. In step 3, based on the engine speed N calculated from the cycle of the reference crank angle signal from the crank angle sensor 10, a table prepared in advance is referenced to search for the determination value ΔSL.

In step 4, the amplitude ΔQ and the judgment value ΔSL
Compare with. If ΔQ <ΔSL, it is considered that the valve is not fully opened, the process proceeds to step 5, the counter WOTC is set to 0, and then the process proceeds to step 8 where it is output that the valve is not fully opened. Δ
If Q ≧ ΔSL, the process proceeds to step 6 and the counter WO
After increasing TC by 1, proceed to step 7. Therefore, the counter WOTC indicates the number of times that the state of ΔQ ≧ SL continues.

In step 7, it is determined whether the counter WOTC is equal to or greater than the determination value SLC. If WOTC <SLC, the process proceeds to step 8 and outputs that the full opening is not performed. W
In the case of OTC ≧ SLC, the state of ΔQ ≧ SL is continuous, so it is considered that the valve is fully opened, and the process proceeds to step 9 to output that the valve is fully opened. This is used for correction control of the fuel injection amount.

Here, the steps 1 and 2 correspond to the amplitude detecting means, and the steps 3 to 9 correspond to the full open judging means. In addition, when the fully closed (idle) detection is required, the intake air flow rate Q detected by the air flow meter 9 may be compared with a predetermined value, and if the intake air flow rate Q is equal to or less than the predetermined value, it may be determined as the fully closed. The predetermined value here may be set according to the water temperature, the duty to the idle control valve, the engine speed, and the like.

[0016]

As described above, according to the present invention, a dedicated position sensor is not required, and the cost can be reduced by deleting the sensor parts and related parts. In addition, accurate full-open detection is possible even in highlands.

[Brief description of drawings]

FIG. 1 is a functional block diagram showing the configuration of the present invention.

FIG. 2 is a diagram showing a relationship between a throttle valve opening and an air flow meter output.

FIG. 3 is a system diagram showing an embodiment of the present invention.

FIG. 4 is a flowchart of a fully open detection routine.

[Explanation of symbols]

 1 engine 3 throttle valve 8 control unit 9 air flow meter

Claims (1)

[Claims] 1. An amplitude detecting means for detecting an amplitude of an output signal of an air flow meter for measuring an engine intake air flow rate, and a fully open judging means for judging that the throttle valve is fully opened when the detected amplitude exceeds a predetermined value. A throttle valve fully open detection device for an internal combustion engine configured to include: