JP2007085257A - Engine rotational speed control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To inject fuel of an amount depending on an engine rotational speed/load states without an influence of open/close states of a bypass air amount control valve in measuring intake pipe pressure, and thereby to prevent an engine malfunction. <P>SOLUTION: The engine rotational speed control device comprises: a bypass air passage BA disposed in an intake passage of an engine E and bypassing a throttle valve; the bypass air amount control valve 10 adjusting a bypass air amount in the bypass air passage by reciprocating motions of a plunger; and a control unit 1 giving a duty drive signal which is synchronous with a crank angle signal of the engine to the bypass air amount control valve to control the bypass air amount control valve to be opened and closed. The control unit outputs a valve open start drive signal of the bypass air amount control valve while an intake valve is closed. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an engine rotation speed control device, and more particularly to a rotation speed control device for a single cylinder engine using a bypass air amount control valve for adjusting an air flow rate by reciprocating movement of a plunger.

  In a conventional multi-cylinder engine rotational speed control device, a bypass air passage that bypasses the throttle valve interposed in the intake passage of the engine is provided, and a bypass air amount control valve is provided in the bypass air passage to perform actual rotation. Feedback control is performed by setting the opening of the bypass air amount control valve so that the speed approaches the target rotational speed.

  In such feedback control, the target rotational speed cannot be realized due to the coarse resolution of the bypass air amount control valve, and the engine rotational speed may cause hunting in the vicinity of the target rotational speed. Also known is feedback control in which hunting is avoided by feeding back the intake air amount in accordance with the amount of dead zone provided in the deviation between the target rotational speed and the actual rotational speed (hereinafter simply referred to as deviation). Yes. (For example, refer to Patent Document 1).

  In addition, in the rotational speed control of a single cylinder engine using a bypass air amount control valve that adjusts the air flow rate by the reciprocating motion of the plunger, the valve opening / closing (ON / OFF) timing is synchronized with the rotational state of the engine. It is common to make it.

JP 2000-45832 A

  FIG. 3 is a schematic diagram showing the relationship between the crank angle signal and the intake pipe pressure when the conventional engine rotational speed control device is configured as described above but the bypass air amount control valve of the single cylinder engine is not driven. As shown in the figure, in the case of a single cylinder engine, the intake pipe pressure change corresponding to each stroke of the engine shown in the figure (b) is considerably large as shown in the figure (f).

  Generally, in the case of a single cylinder engine, the intake pipe pressure measurement value for estimating the intake air amount is obtained by sampling the intake pipe pressure in the open state of the intake valve shown in FIG. Often used.

  FIG. 4 is a schematic diagram showing the relationship between the crank angle signal when the bypass air amount control valve is driven, the bypass air amount control valve, and the intake pipe pressure. FIG. As shown in FIG. 4 (d) and the bypass air amount control valve in the same state (e), the valve opening timing of the bypass air amount control valve is designed to efficiently inhale air. Generally, the intake stroke (intake valve open state) is set.

  Therefore, if the intake pipe pressure changes due to the open / closed state of the bypass air amount control valve, as shown by the broken line in FIG. 4 (f), the same engine speed / load state is obtained. However, since the detected intake pipe pressure varies depending on the drive state of the bypass air amount control valve, the engine control device for determining the fuel injection amount based on the intake pipe pressure value operates the bypass air amount control valve. There is a problem that the influence of cannot be ignored.

Furthermore, when the bypass air amount control valve opening timing is close to the intake valve opening timing, the actual bypass air amount control valve opening timing will be Each time the engine is rotated, a state occurs before and after the intake valve opens and closes, and the intake air amount varies, which promotes engine rotation fluctuations. That is, there is a problem that the state shown in FIG. 4 occurs alternately, for example.
Such a phenomenon is remarkable in an idle state in which the ratio of the bypass air amount is high.

  The present invention has been made to solve the above-described problems, and is not affected by the open / close state of the bypass air amount control valve when measuring the intake pipe pressure. It is an object of the present invention to provide an engine speed control device capable of injecting an amount of fuel corresponding to the engine and preventing engine malfunction.

  An engine rotational speed control device according to the present invention is provided in an intake passage of an engine, bypass air passage that bypasses a throttle valve, bypass air amount control valve that adjusts the bypass air amount of the bypass air passage by a reciprocating motion of a plunger, And an engine rotational speed control device comprising a control unit that applies a duty drive signal synchronized with an engine crank angle signal to the bypass air amount control valve, and controls the opening and closing of the bypass air amount control valve. The control unit outputs a valve opening start drive signal for the bypass air amount control valve while the intake valve is closed.

  Since the engine speed control device according to the present invention is configured as described above, it is not affected by the open / close state of the bypass air amount control valve at the time of intake pipe pressure measurement. An amount of fuel corresponding to the state can be injected, and an engine malfunction can be prevented.

  Even if the bypass air amount control valve is opened only while the intake valve is closed, that is, the bypass air amount control valve is closed before the intake valve is opened, the intake manifold is filled with air, At the intake valve opening timing, the filled air is sent into the engine cylinder, so that the amount of air during idling does not become insufficient.

Embodiment 1 FIG.
Embodiment 1 of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram illustrating a state in which the engine rotation speed control device according to the first embodiment is attached to the engine, and FIG. 2 is a bypass air amount in the state in which the intake valve is closed in the first embodiment. It is a schematic diagram which shows the relationship between a crank angle signal when opening and closing a control valve, a bypass air amount control valve, and an intake pipe pressure.

  In FIG. 1, the control unit 1 measures an intake air temperature sensor 2 that measures the temperature of intake air of the engine E, a throttle position sensor 4 that measures the opening of the throttle valve 3, and an intake air pressure downstream of the throttle valve 3. From the information of the intake pressure sensor 5, the engine temperature sensor 6 that measures the wall temperature of the engine E, and the crank angle sensor 7 that also measures the crank position of the engine E, an appropriate fuel injection timing and fuel injection amount are calculated, and fuel injection is performed. A drive signal is output to the module 8.

  Similarly, an appropriate ignition signal is output to the ignition coil 9 from the information of the various sensors. Further, a bypass air amount control valve 10 is attached to the bypass air passage BA that bypasses the throttle valve 3, and the control unit 1 detects the bypass air amount control valve 10 at an appropriate timing from the information of the various sensors described above. A drive signal is output to the output.

Next, the control operation of the bypass air amount control valve 10 will be described.
For each crank angle signal shown in FIG. 4 (a), the number of the current crank angle signal is checked by a method not shown, and the number of the current crank angle signal is the bypass air amount control valve shown in FIG. 4 (e). If the valve opening timing is 10 (XNUMKAI: crank angle signal # 8 in FIG. 2 (a), crank angle signal # 17 in FIG. 4 (a)), a valve opening start drive signal for the bypass air amount control valve is output.
In addition, the valve opening timing (XNUMKAI) of the bypass air amount control valve is applied to an experimentally obtained optimum value or a timing value at which the intake valve is closed.

  When the crank angle signal number is the valve opening timing (XNUMKAI) of the bypass air amount control valve, after the valve opening start drive signal is output, the valve closing timing of the bypass air amount control valve is then set to various sensors and engine speed. The valve closing start drive signal is output to the bypass air amount control valve 10 using a timer function (not shown) in the control unit 1.

At this time, if it is determined that the closing timing of the bypass air amount control valve calculated above is likely to be close to the intake valve closing timing obtained from the crank angle signal, it is shorter than the timing calculated above. Make corrections to close the bypass air amount control valve over time.
Further, the bypass air amount control valve closing timing is from the opening of the intake valve shown in FIG. 4 (d) to the number of the crank angle signal (XNUMHEI: crank angle signal 2 in FIG. 4 (a)) to be closed. There may be a restriction to do so.

  Also, the closing timing of the bypass air amount control valve is from the closing of the intake valve to the opening of the crank angle signal shown in FIG. 2D (XNUMHEI: crank angle signal 17 of FIG. 2A). There may be a restriction to do so.

  In the above-described embodiment, the multi-projection type has been described in which the crank angle signal generates a plurality of pulses per engine revolution as shown in FIGS. 2 and 4, but one crank angle signal is generated per engine revolution. Control by a crank angle signal of a large protrusion type.

It is a schematic block diagram which shows the state which attached the engine rotational speed control apparatus by Embodiment 1 of this invention to the engine. In Embodiment 1, it is a schematic diagram which shows the relationship between a crank angle signal, a bypass air amount control valve, and an intake pipe pressure when opening and closing a bypass air amount control valve in a state where the intake valve is closed. It is a schematic diagram showing the relationship between the crank angle signal and the intake pipe pressure when the bypass air amount control valve is not driven. It is a schematic diagram showing the relationship between the crank angle signal, the bypass air amount control valve, and the intake pipe pressure when the bypass air amount control valve is driven.

Explanation of symbols

1 control unit, 2 intake air temperature sensor, 3 throttle valve,
4 throttle position sensor, 5 intake pressure sensor, 6 engine temperature sensor,
7 Crank angle sensor, 8 Fuel injection module, 9 Ignition coil,
10 Bypass air amount control valve, 11 Fuel tank, E engine,
BA bypass air passage.

Claims (3)

A bypass air passage that is provided in the intake passage of the engine and bypasses the throttle valve, a bypass air amount control valve that adjusts the bypass air amount of the bypass air passage by a reciprocating motion of a plunger, and an engine crank in the bypass air amount control valve In an engine rotation speed control device including a control unit that gives a duty drive signal synchronized with an angle signal and controls opening and closing of the bypass air amount control valve,
The engine rotation speed control device, wherein the control unit outputs a valve opening start drive signal of the bypass air amount control valve while the intake valve is closed. A bypass air passage that is provided in the intake passage of the engine and bypasses the throttle valve, a bypass air amount control valve that adjusts the bypass air amount of the bypass air passage by a reciprocating motion of a plunger, and an engine crank in the bypass air amount control valve In an engine rotation speed control device including a control unit that gives a duty drive signal synchronized with an angle signal and controls opening and closing of the bypass air amount control valve,
The engine rotation speed control device, wherein the control unit outputs a valve closing start drive signal for the bypass air amount control valve while the intake valve is open. A bypass air passage that is provided in the intake passage of the engine and bypasses the throttle valve, a bypass air amount control valve that adjusts the bypass air amount of the bypass air passage by a reciprocating motion of a plunger, and an engine crank in the bypass air amount control valve In an engine rotation speed control device including a control unit that gives a duty drive signal synchronized with an angle signal and controls opening and closing of the bypass air amount control valve,
The engine rotation speed control device, wherein the control unit outputs a valve closing start drive signal for the bypass air amount control valve while the intake valve is closed.

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