JPH056648B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to an intake air amount measuring device that measures the intake air amount of an internal combustion engine based on the Karman vortex generation period.

Prior Art and Problems In an internal combustion engine, the intake air amount of the engine is generally measured, and the fuel injection amount is controlled based on the measurement result so that the air-fuel ratio is kept constant. Various measuring devices for measuring the intake air amount have been proposed in the past, and for example, a measuring device for measuring the intake air amount based on the Karman vortex generation cycle has also been proposed. This measuring device measures the intake air amount of an internal combustion engine by utilizing the fact that the intake air amount is inversely proportional to the Karman vortex generation period, but it has the following drawbacks. In other words, conventional devices detect the Karman vortex generation cycle at regular intervals and measure the amount of intake air based on the detection results, but even when the internal combustion engine is in a steady state, the amount of intake air depends on the intake stroke. , the compression process, the exhaust process, etc. Therefore, if the Karman vortex generation cycle is detected at fixed timings, the detection results will be different even when the internal combustion engine is in a steady state. Controlling the fuel injection amount based on the measurement results of the amount measuring device has the disadvantage that the rotation of the internal combustion engine becomes unstable.

OBJECTS OF THE INVENTION The present invention has been made to improve the above-mentioned drawbacks, and its purpose is to make it possible to accurately measure the amount of intake air depending on the state of the internal combustion engine.

Structure of the Invention In order to achieve the above object, the present invention, as shown in FIG. An air amount sensor 1 that generates a Karman vortex at a corresponding cycle and outputs a Karman vortex signal at a cycle corresponding to the generation cycle of the Karman vortex.
00, and a rotation angle sensor 101 that outputs a rotation angle position signal every time the internal combustion engine 1 rotates by a predetermined angle.
and determining means 102 for determining whether or not a specific rotation angle position signal corresponding to the center value of the amplitude of the pulsation of the intake air amount is output from the rotation angle sensor 101;
After the determining means 102 determines that the specific rotation angle position signal is output, the air amount sensor 10
a detection means 103 for detecting the time from the output timing of the Karman vortex signal outputted first to the output timing of the Karman vortex signal outputted next; This is an intake air amount measuring device for an internal combustion engine 1 characterized in that it includes a calculating means 104 for calculating the amount.

Embodiment of the Invention FIG. 2 is a block diagram of an embodiment of the present invention, in which 1 is an internal combustion engine, 2 is an air cleaner, and 3 is a Karman vortex type air amount sensor, which outputs an output every time a Karman vortex is generated. This sets the signal a to "1". 4 is a throttle chamber, 5 is an intake manifold, 6 is an electromagnetic fuel injector, 7 is a throttle valve that controls the flow of intake air, and 8 is shown in Fig. 3A every 30° rotation of the crank. 9 is a microprocessor, 10 is a crank angle sensor that outputs rotation angle position signals C ₀ to C ₁₁ as shown in FIG.
1 is a memory, 11 is a data input section, and 12 is a data output section.

Intake air is supplied from an air cleaner 2 to each cylinder from each branch of an intake manifold 5 via an air amount sensor 3 and a throttle chamber 4, and fuel is injected into the internal combustion engine 1 by a fuel injector 6. Further, when the internal combustion engine is in a steady state, the intake air amount changes in accordance with the crank angle as shown in FIG. 3B. Then, the specific rotation angle position signal is shown as shown in the figure.
C ₆ corresponds to the center value of the amplitude of the pulsation of the intake air amount.

FIG. 4 is a flowchart showing the processing contents of the microprocessor 9, and the operation of FIG. 2 will be explained below with reference to FIG.

The microprocessor 9 receives a specific rotation angle position signal from the crank angle sensor 8 via the data input section 11.
C Determine whether ₆ has been added (step
S1). If it is determined that the specific rotational angle position signal _C6 has been applied, the microprocessor 9 detects the specific rotational angle position signal _C6 at the timing when the output signal a of the air amount sensor 3 first becomes "1". Find the time until the next signal a becomes "1", that is, the period of the first signal a (step
S2). Next, the microprocessor 9 executes step S2.
The amount of intake air is determined based on the period of the signal a determined in step S3. Here, as mentioned above, the air amount sensor 3 sets its output signal a to "1" every time a Karman vortex is generated, and the generation period of the Karman vortex is inversely proportional to the intake air amount, and furthermore, at a specific rotation speed. Since the angular position signal _C6 corresponds to the center value of the pulsation of the intake air amount, the pulsation of the intake air amount is determined based on the period of the first signal a at the specific rotational angular position of the internal combustion engine 1 determined in step S2. The center value of the amplitude of can be found.

Next, the microprocessor 9 determines the fuel injection amount corresponding to the intake air amount determined in step S3 (step S4), and then determines whether the fuel injection timing has arrived based on the rotation angle position signal from the crank angle sensor 8. (Step S5). When determining that the fuel injection timing has come, the microprocessor 9 applies a control signal to the data output section 12.
The output signal b is set to "1" for a time corresponding to the fuel injection amount determined in step S4 (step S4).
S6), whereby the amount of fuel determined in step S4 is injected from the fuel injector 6 into the internal combustion engine 1. For example, if fuel is to be injected at the timing when the rotation angle position signal C ₀ is output from the crank angle sensor 8, the microprocessor 9
At the timing when the rotational angular position signal _C0 is detected, a control signal is applied to the data output section 12, the output signal b is set to "1", and the data is stored for a time corresponding to the fuel injection amount determined in step S4, and then stored as a file. A predetermined amount of fuel is injected from the fuel injector 6. This fuel injection amount control is performed by the data output section 12.
This can be easily achieved by using a down counter.
After the microprocessor 9 completes the process at step S6, it returns to the process at step S1.

In this way, in this embodiment, the intake air amount is determined based on the cycle of the first signal a at the timing when the specific rotation angle position signal _C6 indicating the center value of the amplitude of the pulsation of the intake air amount is detected. When the internal combustion engine is in a steady state, the amount of intake air changes in response to the crank angle as shown in FIG. 3B. According to this embodiment, when the internal combustion engine is in a steady state, Unlike the conventional example, the measurement results no longer differ depending on the measurement timing.

The specific rotation angle position signal C ₆ corresponds to _the center value of the amplitude of the pulsation of the intake air amount.
It is sufficient to calculate the center value of the pulsation of the air amount by simply finding the period of the first signal a after detecting , so the intake air amount can be measured with high accuracy.
Moreover, this calculation process becomes extremely simple.

Effects of the Invention As explained above, the present invention is capable of starting from the output timing of the Karman vortex signal that is first output after the generation of the specific rotational angle position signal corresponding to the center value of the amplitude of the pulsation of the intake air amount. The central value of the amplitude of the pulsation of the intake air amount can be calculated simply by determining the time until the output timing of the Karman vortex signal, so the intake air amount can be measured accurately and accurately. It has the advantage of being simple.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of the present invention, FIG. 2 is a block diagram of an embodiment of the present invention, FIG. 3 is a diagram showing the output signal of the crank angle sensor and the amount of intake air, and FIG. 4 is the microprocessor 9. This is a flowchart showing the processing contents. 1 is an internal combustion engine, 2 is an air cleaner, 3,100
is an air amount sensor, 4 is a throttle chamber, 5 is an intake manifold, 6 is a fuel injector, 7 is a throttle valve, 8 is a crank angle sensor, 9 is a microprocessor, 10 is a memory, 1
1 is a data input section, 12 is a data output section, 101
1 is a rotation angle sensor, 102 is a judgment means, 103 is a detection means, and 104 is a calculation means.

Claims (1)

[Claims] 1. In an internal combustion engine intake air amount measurement device that measures the pulsating intake air amount in an internal combustion engine, a Karman vortex is generated at a period corresponding to the intake air amount, and a Karman vortex is generated at a period corresponding to the generation period of the Karman vortex. an air amount sensor that outputs a vortex signal; a rotation angle sensor that outputs a rotation angle position signal every time the internal combustion engine rotates by a predetermined angle; a determining means for determining whether or not a specific rotation angle position signal has been output; and the Karman vortex signal that is first output from the air amount sensor after the determining means determines that the specific rotation angle position signal has been output. A detection means for detecting the time from the output timing of the Karman vortex signal to the next output timing of the Karman vortex signal, and a calculation means for calculating the intake air amount based on the detection result of the detection means. This is an intake air amount measuring device for internal combustion engines.