JPH02267345A - Intake air flow measuring device for internal combustion engine with supercharging device - Google Patents

Abstract

PURPOSE:To improve the measuring accuracy of the intake air flow at the time of intake pulsation by detecting the event time of intake air flow change from a deceleration time intake pulsation cycle and enumerating the net intake air flow from the difference between the integrated value of the intake air flow until the flow direction inversion event time and that after the inversion event time. CONSTITUTION:The title device is provided with a transition event time detecting means 42 for detecting the first event time when the intake air flow detected by a hot-wire type air flow sensor 24 changes from its decreasing change to increasing change after the start of deceleration, at the time of deceleration judged from the output of a throttle switch 34 and an engine sensor 32. There are also provided with a detecting means 44 for detecting the event time when the intake air flow is inverted from the back flow state to the normal flow state and a discriminating means 46 for discriminating the event time when the intake air flow is inverted from the normal flow state to the back flow state on the basis of the intake pulsation cycle at the time of deceleration, with a transition event time as a starting point. The net intake air flow is enumerated by an enumerating means 50 from the difference between the integrated value of the intake air flow until the flow direction inversion event time by every cycle of the deceleration time intake pulsation and that after the inversion event time.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an intake air amount measuring device for an internal combustion engine equipped with a supercharging device, and in particular is provided in an intake passage upstream of a supercharging device to The present invention relates to a type of intake air amount measuring device that determines the amount of intake air from a detected value from an air amount detection means that cannot identify the air amount.

[Prior Art] In an internal combustion engine equipped with a supercharging device, if a sudden deceleration is performed from a supercharging state, supercharging will not be performed for a while even after the throttle valve is closed due to the response delay of the supercharging device. As a result, the pressure in the intake passage downstream of the supercharging device increases, which causes intake air to flow back upstream of the supercharging device,
Then, this backflow intake air is sucked in by the supercharging device again, and as this is repeated, an intake pulsation phenomenon occurs for 2.3 seconds.

If the air amount detection device is of a type that cannot identify the flow direction of intake air, such as a hot wire intake air amount sensor, it will not be possible to accurately measure the amount of intake air during the intake pulsation period as described above. .

In view of the above-mentioned problems, we found that the flow direction of the intake air had reversed from the change in the amount of intake air detected by the air amount detection means, and calculated the net intake air by subtracting the flow rate during the reverse flow from the flow rate during the forward flow. It has already been proposed to calculate the amount, and this is shown, for example, in Japanese Patent Laid-Open Publication No. 148821/1983.

[Problems to be Solved by the Invention] In order to measure the net intake air amount, it is necessary to detect the start of reverse flow of intake air and the end of reverse flow, that is, the start of normal flow, as the points at which the flow direction of intake air is reversed. In conventional measuring devices, each of these is detected from the change in the intake air amount detected by the air amount detection means for each cycle of the intake pulsation. If the amplitude of the intake pulsation is relatively large, the point of reversal of the intake flow direction can be found relatively accurately from the change in intake air amount. Since the intake pulsation attenuates over time, in this case, the measuring device described above will not necessarily accurately detect all the points at which the intake flow direction reverses, and therefore the net injected air amount may not be calculated correctly. be.

In addition, in the conventional net intake air amount measuring device as described above, all points at which the intake air flow reverses must be detected from changes in the intake air amount. There is a problem that the number increases.

SUMMARY OF THE INVENTION An object of the present invention is to provide an intake air amount measuring device that can accurately measure the amount of intake air during intake pulsation during deceleration due to response delay of a supercharging device.

[Means for Solving the Problems] According to the present invention, the above-mentioned object is to provide an intake system that measures the amount of intake air based on the detected value from the air amount detection means provided in the intake passage upstream of the supercharging device. In the air amount measuring device,
transition point detection means for detecting the point in time when the intake air amount detected by the air amount detection means first changes from a decreasing change to an increasing change after the start of deceleration of the internal combustion engine; flow direction reversal point detection means for detecting the point in time when the flow of intake air is reversed from a reverse flow state to a forward flow state based on a change in the intake air amount; flow direction reversal point determining means for determining the point in time when the flow of intake air is reversed from a forward flow state to a reverse flow state based on a period of intake pulsation during deceleration that is predetermined depending on the source; Based on the time points found by each of the flow direction reversal point detection means and the flow direction reversal point determination means, the integrated value of the intake air amount up to the flow direction reversal point and the flow direction reversal point are determined for each cycle of intake pulsation during deceleration. an integrating means for calculating the integrated value of the subsequent intake air amount; and an integrated value of the intake air amount up to the time of flow direction reversal, which is integrated by the integrating means at the end of each cycle of the intake pulsation during deceleration, and the flow direction reversal. This is achieved by an intake air amount measuring device for an internal combustion engine with a supercharger, which has a net intake air amount calculation means for calculating the net intake air amount from the difference between the intake air amount and the integrated value after the point in time.

[Operations and Effects of the Invention] In the intake air ffi δ-1 constant device according to the present invention, the period of intake pulsation during deceleration caused by the response delay of the supercharging device is independent of the engine speed and Focusing on the fact that it is uniquely determined by the specifications (length, volume, cross-sectional area) of the intake passage space from the air inlet end to the throttle valve, the period of intake pulsation during deceleration is determined in advance according to the intake system specifications. The point at which the flow of intake air changes from a forward flow state to a reverse flow state is determined. Therefore, in the present invention, in order to calculate the net intake air amount, the point at which the flow direction of intake air is reversed is determined. It is only necessary to detect a change in the amount of intake air when the flow of intake air reverses from a reverse flow state to a forward flow state. Therefore, the detection items from the change in intake air amount required to measure the net intake air amount are the point when the intake air first begins to flow backwards, and the point at which the flow of intake air reverses from a forward flow state to a reverse flow state. only at the point in time. As a result, even if the intake pulsation attenuates over time and its amplitude becomes smaller, the degree to which the net intake air amount is accurately measured is improved compared to the conventional method, and the reliability of the measured value is improved. You will start to improve.

[Example] The present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 shows one embodiment of an internal combustion engine with a supercharging device that uses an intake air amount measuring device according to the present invention. 1st
In the figure, 10 is the internal combustion engine body, 12 is the intake port, 14 is the exhaust boat, 16 is the fuel injector, 1
8 is a surge tank, 20 is a throttle valve, 22 is a supercharging device, especially its compressor part, 24 is a hot wire type air amount sensor provided in the intake passage 26 upstream of the supercharging device 22, and 28 is a hot wire air amount sensor. Each air cleaner is shown.

The amount of fuel injected by the fuel injector 16 is controlled by an electronic control device 30 including a microcomputer. The electronic control device 30 receives information regarding the intake air amount from the hot-wire type air amount sensor 24 having an internal membrane structure, information regarding the engine speed from the engine speed sensor 32, and information regarding the idle opening position of the throttle valve 20 from the throttle switch 34. The fuel injection amount by the fuel injector 16 is controlled according to this information.

The electronic control unit 30 includes an intake air amount measuring device 40 according to the present invention as shown in FIG.

The intake air amount measuring device 40 includes a transition point detection means 42;
It has a flow direction reversal time point detection means 44, a flow direction reversal time point determination means 46, an integration means 48, and a net intake air amount calculation means 50.

When the throttle switch 34 detects that the throttle valve 20 is at the idle opening position and the engine speed sensor 32 detects that the engine speed is equal to or higher than a predetermined value, the transition point detection means 42 determines that the deceleration is occurring. After the start of deceleration, the point in time when the intake air amount detected by the hot-wire air amount sensor 24 first changes from a decreasing change to an increasing change, that is, time A in FIG. 3 is detected.

The flow direction reversal point detection means 44 detects the point at which the flow of the intake air is reversed from the reverse flow state to the forward flow state based on the change in the intake air amount detected by the hot wire air amount sensor 24, that is, the third point.
Time point B in the figure is detected.

The flow direction reversal point determination means 46 is the transition point detection means 4.
Starting from the transition point A detected in step 2, the intake system specifications, that is, the spatial dimensions of the intake passage from the air cleaner 28, which is the air inlet end of the intake passage, to the throttle valve 2° (
Based on the predetermined period T of the intake pulsation during deceleration, which is uniquely determined by the length, volume, cross-sectional area), the point at which the intake air flow next reverses from the forward flow state to the reverse flow state, that is, the third
In the figure, time C is detected.

The integrating means 48 performs deceleration based on the time point A detected by the transition time point detection means 42, the time point B detected by the flow direction reversal time point detection means 44, and the time C determined by the flow direction reversal time point detection means 46. The cumulative value NG of the intake air amount up to the time when the flow direction is reversed for each period of intake pulsation, that is, the cumulative value NG of the intake air amount during the reverse flow state from time A or from time C to time B, and the flow direction The integrated value PC of the amount of intake air after the reversal point, that is, the integrated value PG of the amount of intake air in the normal flow state from time B to time C is determined.

The net intake air amount calculating means 50 calculates the integrated value NG of the intake air amount up to the point of reversal of the flow direction, which is accumulated by the integrating means 48 at the end of each cycle of the intake pulsation during deceleration, and the amount of intake air after the point of reversal of the flow direction. The net intake air ff1cG is calculated from the difference between the integrated value PG and the integrated value PG. Information regarding this net intake air ff1cG is obtained from the fuel injector 1.
6 is output to its control circuit in order to control the fuel injection amount.

FIG. 4 shows a routine for measuring the intake air amount using the intake air amount measuring device configured as described above.

The intake air ff1cJ constant routine shown in FIG. It will be done. Since the hot wire type air amount sensor 24 cannot identify the flow direction of the intake air, the air f detected by the hot wire type air amount sensor 24
f1G includes the amount of air in the forward flow state and the amount of air in the reverse flow state.

After step 10, proceed to step 20;
At this point, it is determined whether a flag F indicating that a backflow correction logic calculation is in progress is 1 or not. When F-1, that is, when the calculation is in progress, the process proceeds to step 80; otherwise, the process proceeds to step 30.

In step 30, it is determined whether or not the vehicle is in a deceleration state based on information from the throttle switch 34 and information from the engine speed sensor 32. If the vehicle is in a deceleration state, the process proceeds to step 40; otherwise, the process proceeds to step 50.

In step 40, it is determined whether the current air ff1G is smaller than the minimum value G sin after the start of deceleration. When Q < G 1n, the air ff1G is still decreasing, in which case the process proceeds to step 50; otherwise, when the air ff1G changes from a decreasing change to an increasing change, the process proceeds to step 6o. .

In step 50, the current air mG is set to a new minimum value G min.

In step 60, it is determined whether the difference between the current air mG and the first minimum value G iln after deceleration has become larger than ΔG. When G-Gmln>ΔG, it is assumed that the air ff1G clearly changes from a decreasing change to an increasing change after the gear shift, that is, at time A, and the process proceeds to step 70.

In step 70, the flag F is set to 1, the counter is reset to 0, and counting up is started.

Step 80 is executed when flag F is determined to be 1 in step 7o, and in step 80,
Based on the change in the engine speed detected by the engine speed sensor 32, it is determined whether or not the engine is in an acceleration state. If the acceleration state is present, the process proceeds to step 170 to stop the backflow correction logic calculation, and if not, the process proceeds to step 90 to start the backflow correction logic calculation.

In step 90, it is determined whether the count value CNT of the counter is equal to 2N-1. 2N-1 is a predetermined setting value corresponding to the period T of the intake pulsation during deceleration, and when CNT-2N-1 is set, it corresponds to the period C of the intake pulsation during deceleration at time C in FIG. This is the end point, in which case the process proceeds to step 180; otherwise, in other words during the cycle, the process proceeds to step 100.

In step 100, it is determined whether the current air ff1G is smaller than the minimum value G min.

C: When < G min, it is before time A or time C reaches time B, that is, when the intake air is flowing backwards, and in this case, proceed to step 110, otherwise proceed to step 130. .

In step 110, the current air amount is set to a new minimum value G sin. After step 110, the process proceeds to step 120.

In step 120, the integrated value GN of the amount of intake air during backflow is integrated (NG - NG0G). Step 1
After step 20, the process proceeds to step 150.

In step 130, it is determined whether the difference between the current air ff1G and the minimum value G sin is greater than a predetermined value ΔG. When G-Gmin>ΔG, it is the point B when the intake air flow clearly reverses from the reverse flow state to the forward flow state.
If so, the process proceeds to step 140; otherwise, the process proceeds to step 120.

In step 140, the integrated value PG of the amount of intake air during normal flow is integrated (PG-PG0G). Step 1
After step 40, the process proceeds to step 150.

In step 150, the counter count value CNT
is between O and 2N-1, that is, the maximum value G2 and minimum value G of air ff1G during one cycle of intake pulsation during deceleration,
and is memorized.

After step 150, the process proceeds to step 160.

In step 160, it is determined whether the difference between the maximum value G2 and the minimum value G1 has become equal to or less than a predetermined value G set. If G 2 - G 1 < G set, it is determined that the intake pulsation during deceleration has ended and the process proceeds to step 170.

In step 170, flag F is set to 0.

Step 180 is executed every time point C, step 180
In this case, the net intake air ff is calculated by subtracting the cumulative value GN of the intake air amount during reverse flow from the cumulative value PG of the intake air volume during forward flow.
Calculation of 1cG is performed. Also step 180
In this case, the counter is reset, the up-counting of this counter is restarted, and the integrated values PG and NG are each reset to 0.

Although the present invention has been described in detail with respect to specific embodiments above, the present invention is not limited thereto.
It will be apparent to those skilled in the art that various embodiments are possible within the scope of the invention.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram showing one embodiment of an internal combustion engine with a supercharging device using an intake air m DI constant device according to the present invention, and FIG. 2 is an embodiment of an intake air Q aP+ constant device according to the present invention. Figure 3 is a block diagram showing an example of changes in the flow direction of intake air during intake pulsation during deceleration in an internal combustion engine equipped with a supercharger, and changes in the intake air amount detected by the air amount detection means. FIG. 4 is a flowchart showing the intake air ffi measurement routine of the intake air amount measuring device according to the present invention. 10... Internal combustion engine body, 12... Intake port, 14
Exhaust port, 16...Fuel injector, 18...
Surge tank, 20... Throttle valve, 22... Supercharger, 24... Hot wire type air amount sensor, 26... Intake passage. 28... Air cleaner, 30... Electronic control device, 3
2... Engine rotation speed sensor, 34... Throttle switch 40... Intake air amount measuring device, 42... Transition point detection means, 44... Flow direction reversal point detection means, 4
6... Means for determining the time of flow direction reversal, 48... Integrating means, 50... Means for calculating net intake air amount Patent application Attorney Toyota Motor Corporation

Claims (1)

[Claims] In an intake air amount measuring device that measures an intake air amount from a value detected by an air amount detecting means provided in an intake passage upstream of a supercharging device, the air amount detecting means a transition point detection means for detecting the point in time when the intake air amount detected by the above first changes from a decreasing change to an increasing change; and a transition point detection means for detecting the point in time when the intake air amount detected by the air amount first changes from a decreasing change to an increasing change; flow direction reversal point detection means for detecting the point in time when the flow direction is reversed to a more positive flow state;
The point in time when the flow of intake air reverses from a forward flow state to a reverse flow state based on the period of intake pulsation during deceleration, which is predetermined according to the intake system specifications, with the transition time detected by the transition time detection means as the starting point. flow direction reversal point determination means for determining the flow direction reversal time point determination means, the transition time point detection means, the flow direction reversal time point detection means, and the flow direction reversal time point determination means, each cycle of the intake pulsation during deceleration. an integrating means for calculating the integrated value of the intake air amount up to the time when the flow direction is reversed and the integrated value of the intake air amount after the time when the flow direction is reversed;
The net intake is calculated from the difference between the integrated value of the intake air amount up to the point of reversal of the flow direction, which is accumulated by the integrating means at the end of each cycle of the intake pulsation during deceleration, and the integrated value of the amount of intake air after the point of reversal of the flow direction. An intake air amount measuring device for an internal combustion engine with a supercharger, comprising a net intake air amount calculating means for calculating an air amount.