JP2018105170A - Spark-ignition type multi-cylinder engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a spark-ignition type multi-cylindrical engine capable of attaining limp home operation where engine stall or rotation abnormality hardly occurs in engine abnormality.SOLUTION: A spark-ignition type multi-cylinder engine includes an abnormality detection device 5 configured to detect engine abnormality. On the basis of predetermined abnormality detection of the abnormality detection device 5, an operation control mode is set to a limp home operation mode in an electronic control device 4. In the limp home operation mode, only combustion in a specific cylinder C1 is executed, fuel injection of a fuel injector I2 to another cylinder C2 is stopped, and then cylinder reduction operation of stopping combustion in the cylinder C2 is executed.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a spark-ignition multi-cylinder engine, and more particularly to a spark-ignition multi-cylinder engine that can realize limp home operation in which engine stall and rotation abnormality hardly occur when the engine is abnormal.

  Conventionally, a throttle valve, a mechanical governor that controls the throttle valve, an intake air amount detection device, a fuel injector, and an electronic control that controls the fuel injection amount from the fuel injector according to the intake air amount detected by the intake air amount detection device There is a spark ignition type multi-cylinder engine equipped with a device (see, for example, Patent Document 1).

  According to this type of engine, there is an advantage that it is possible to reduce the burden of electronic control by the electronic control unit by controlling the slot valve by the mechanical governor.

JP 2008-223525A (see FIG. 1)

<Problem> Engine stalls and rotation abnormalities are likely to occur during limp home operation.
Patent Document 1 does not refer to limp home operation. However, in the limp home operation when the engine is abnormal, when the electronic control for reducing the fuel injection amount is performed to limit the output, the mechanically controlled throttle valve As the injection amount decreases, the intake air amount cannot be reduced, the air-fuel ratio falls outside the appropriate range, and engine stall or rotation abnormality tends to occur.

  An object of the present invention is to provide a spark ignition type multi-cylinder engine capable of realizing limp home operation in which engine stall and rotation abnormality hardly occur when the engine is abnormal.

The invention specific matters of the present invention are as follows.
As illustrated in FIG. 1, a throttle valve (1), a mechanical governor (2) for controlling the throttle valve (1), an intake air amount detection device (3), fuel injectors (I1) (I2), an intake air In a spark ignition type multi-cylinder engine provided with an electronic control unit (4) for controlling the fuel injection amount from the fuel injectors (I1) and (I2) according to the intake air amount detected by the amount detection device (3),
As illustrated in FIG. 1, an abnormality detection device (5) that detects an engine abnormality is provided, and an electronic control device (4) is illustrated in FIG. 5 based on a predetermined abnormality detection by the abnormality detection device (5). As described above, the operation control mode is set to the limp home operation mode (S3). In the limp home operation mode (S3), only the combustion of the specific cylinder (C1) illustrated in FIGS. Spark ignition is characterized in that the fuel injection by the fuel injector (I2) to the cylinder (C2) is stopped and the reduced-cylinder operation in which the combustion of the cylinder (C2) is stopped is performed. Type multi-cylinder engine.

The present invention has the following effects.
<Effect> It is possible to realize limp home operation in which engine stall and rotation abnormality hardly occur when the engine is abnormal.
In the present invention, as illustrated in FIG. 5, the operation mode is set to the limp home operation mode (S3) based on a predetermined abnormality detection, and the limp home operation mode (S3) is illustrated in FIGS. Only the combustion of the specific cylinder (C1) is performed, the fuel injection by the fuel injector (I2) to the other cylinder (C2) is stopped, and the combustion in the cylinder (C2) is stopped. Since the restriction is made, there is no problem that the air-fuel ratio deviates from an appropriate range, and it is possible to realize limp home operation in which engine stall and rotation abnormality are unlikely to occur.

1 is a longitudinal front view of an engine according to an embodiment of the present invention. FIG. 2 is a longitudinal side view of the engine of FIG. 1, with the fuel injection device omitted. It is the top view of the engine of FIG. 1, and is a figure which abbreviate | omitted the mechanical governor, the fuel-injection apparatus, and the upper cover. It is a front view of the engine of FIG. It is a flowchart of control by the electronic controller of the engine of FIG.

  FIGS. 1 to 5 are diagrams for explaining a spark ignition type multi-cylinder engine according to an embodiment of the present invention. In this embodiment, a fuel injection type and spark ignition type air-cooled V-type two cylinder engine is shown in this embodiment. explain.

The outline of this engine is as follows.
As shown in FIG. 2, the installation direction of the crankshaft (10) is the front-rear direction, one is front, the other is rear, and as shown in FIG. 1, the horizontal direction perpendicular to the front-rear direction is viewed from the left-right direction and the rear. Let the left hand side be left and the right hand side be right.
As shown in FIG. 1, this engine has left and right cylinders (C1) and (C2) that are obliquely upward and leftward from the upper left and right positions of the crankcase (11) when viewed in a direction parallel to the installation direction of the crankshaft (10). ) Projecting cylinder blocks (12), left and right cylinder heads (13) (13) attached to the projecting ends of the left and right cylinders (C1) and (C2), and left and right cylinder heads (13) (13) ) And left and right cylinder head covers (14) and (14) respectively, an engine cooling fan (15) disposed in front of the cylinder block (12) shown in FIG. 2, and FIGS. A fan cover (16) covering the engine cooling fan (15), an intake device (17) shown in FIGS. 1 to 3, a mechanical governor (2) shown in FIG. 1, a fuel injection device (18), and an intake device The front of (17) and the front of the fuel injection device (18) Figure 1 covers from, and a cover (19) on which is shown in FIG. The engine cooling air generated by the engine cooling fan (15) passes between the left and right cylinders (C1) and (C2) and the laterally outer sides of the left and right cylinders (C1) and (C2), and passes through each cylinder (C1). (C2) is air-cooled.

As shown in FIGS. 1 to 3, the intake device (17) includes a throttle body (20), an intake introduction pipe (21) for introducing intake air to the throttle body (20), and left and right sides from the throttle body (20). An intake manifold (22) for distributing intake air to the cylinders (C1) and (C2) is provided.
The mechanical governor (2) is a governor lever (not shown) that swings according to the unbalanced force between the governor force of a governor weight (not shown) and the spring force of a governor spring (not shown) according to the engine speed and load. ) Of the throttle valve (1) of the throttle body (20) shown in FIG.

As shown in FIG. 1, the fuel injection device (18) includes an intake air amount detection device (3), a fuel supply pump (23), and a delivery pipe (24) for distributing fuel from the fuel supply pump (23). The left and right fuel injectors (I1) (I2) for injecting the fuel distributed by the delivery pipe (24) to the left and right cylinders (C1) (C2), respectively, and the intake air based on the detection of the intake air amount detection device (3) An electronic control unit (4) is provided for metering control of the fuel injection amount injected from the left and right fuel injectors (I1) and (I2) in correspondence with the amount.
The electronic control unit (4) is an engine ECU. The engine ECU is an abbreviation for engine electronic control unit and is a microcomputer. The intake air amount detection device (3) detects the intake air amount by calculating the detection value of the air flow sensor by the electronic control device (4). The intake air amount detection device (3) detects the intake air amount by calculating detection values of an intake pressure sensor (not shown) and an engine speed detection sensor (26) by an electronic control device (4). Also good.

As shown in FIG. 1, the electronic control unit (4) includes left and right ignition coils (25) and (25) that supply high-voltage current to the ignition plugs (P1) and (P2) of the left and right cylinders (C1) and (C2). Control and set ignition timing according to engine speed and load.
The left and right ignition coils (25) and (25) are attached to a delivery pipe (24).

  As shown in FIG. 1, this engine includes a throttle valve (1), a mechanical governor (2) for controlling the throttle valve (1), an intake air amount detection device (3), and fuel injectors (I1) (I2). And an electronic control unit (4) for controlling the fuel injection amount from the fuel injectors (I1) (I2) according to the intake air amount detected by the intake air amount detection device (3).

  As shown in FIG. 1, this engine is provided with an abnormality detection device (5) for detecting an engine abnormality. Based on a predetermined abnormality detection by the abnormality detection device (5), the electronic control device (4) As shown in FIG. 3, the operation control mode is the limp home operation mode (S3). In the limp home operation mode (S3), only the combustion of the specific cylinder (C1) shown in FIGS. The fuel injection by the fuel injector (I2) to the cylinder (C2) is stopped, and the cylinder reduction operation is performed in which the combustion of the cylinder (C2) is stopped.

  As shown in FIG. 5, according to the above configuration, the operation mode is set to the limp home operation mode (S3) based on the predetermined engine abnormality detection, and in the limp home operation mode (S3), the specific cylinder (C1) Since the fuel injection by the fuel injector (I2) to the other cylinder (C2) is stopped and the combustion of the cylinder (C2) is stopped, the output is limited by the reduced-cylinder operation. There is no problem that the air-fuel ratio deviates from an appropriate range, and limp home operation that is unlikely to cause engine stall or rotation abnormality can be realized.

  In this embodiment, the specific cylinder (C1) in which combustion is performed in the reduced cylinder operation in the limp home operation mode (S3) is the first cylinder on the front side, and the other cylinder (C2) in which combustion is stopped is on the rear side. The fuel injector (I1) of the second cylinder and the first cylinder (C1) is a first fuel injector, and the fuel injector (I2) of the second cylinder (C2) is a second fuel injector.

As shown in FIG. 1, in this engine, the abnormality detection device (5) includes an engine wall temperature detection sensor (5a) for detecting engine wall temperature, a cooling air temperature detection sensor (5b) for detecting engine cooling air temperature, An oil temperature detection sensor (5c) for detecting the temperature of the engine oil, an intake air temperature detection sensor (5d) for detecting the intake air temperature, and a hydraulic pressure detection sensor (5e) for detecting the circulating oil pressure of the engine oil are provided. Based on the detection, the predetermined abnormality is detected by the electronic control unit (4).
The engine wall temperature detection sensor (5a) detects the temperature of the walls of the cylinder block (12) and the cylinder head (13).

  With the above configuration, the engine operation mode is set to the limp home operation mode (S3) when the engine is abnormal due to an abnormal increase in engine engine temperature or an abnormal decrease in circulating oil pressure. Damage can be suppressed.

In this embodiment, the engine abnormality detection condition is that the detection value of any of the temperature sensors (5a) to (5d) shown in FIG. 1 exceeds a predetermined reference value, or the detection value of the hydraulic pressure detection sensor (5e). Is less than a predetermined reference value.
The setting of the limp home operation mode (S3) shown in FIG. 5 is such that the values of the predetermined sensors (5a) to (5e) shown in FIG. 1 satisfy the engine abnormality detection condition and the values satisfying the engine abnormality detection condition. This is done when a limp home setting condition that falls within a predetermined value range is satisfied.
When the value satisfying the engine abnormality detection condition is greatly deviated to the abnormal side from the predetermined value range, the engine stop process (S6) shown in FIG. 5 is performed, and when deviating to the normal side, a warning is given. Processing (S7) is performed, the engine operation mode is changed to the normal operation mode, and all-cylinder operation is performed.

With the above settings, proper limp home operation is realized when the engine is abnormal, and as shown in FIG. 5, even in the limp home operation mode (S3), when the abnormality is such that the engine may be fatally damaged, When the engine stop process (S6) is performed and the engine is abnormal, but the abnormality is not small enough to set the limp home operation mode urgently, a warning process (S7) is performed and the engine operation mode is set to the normal operation mode. Is done.

Specific examples of various conditions are as follows.
When the temperature increases in the order of T1, T2, and T3, the engine abnormality detection reference value is set to T1, and the limp home setting value range is set to a range of T2 to T3.
In this case, the engine abnormality detection condition is satisfied based on the detection temperature T of any one of the temperature detection sensors (5a) to (5d) shown in FIG. 1 exceeding the reference temperature T1, and the detection temperature T is further increased. When it is within the range of T2 to T3, the setting condition of the limp home operation mode (S3) shown in FIG. 5 is satisfied.
If the detected temperature T exceeds T3, the engine stop process condition is satisfied, the engine stop process (S6) shown in FIG. 5 is performed, and if it is within the range of T1 to T2, a warning process is performed. The condition is satisfied and a warning process (S7) is performed.

When the pressure decreases in the order of P3, P2, and P1, the engine abnormality detection reference value is set to P3, and the limp home setting range is set to the range of P2 to P1.
In this case, based on the fact that the detected pressure P of the hydraulic pressure detection sensor (5e) shown in FIG. 1 has become lower than the reference temperature P3, the engine abnormality detection condition is satisfied, and the detected pressure P is further in the range of P2 to P1. If it is, the setting conditions for the limp home operation mode (S3) shown in FIG. 5 are satisfied.
If the detected pressure P is less than P1, the engine stop process condition is satisfied, the engine stop process (S6) shown in FIG. 5 is performed, and if the detected pressure P is within the range of P3 to P2, a warning is given. Processing conditions are satisfied, and warning processing (S7) is performed.

  In the case of the warning process (S7) shown in FIG. 5, a warning is given by a warning notification device (not shown). In the case of setting the limp home operation mode (S3) and the engine stop (S6), the engine stop notification device (not shown) and the operation mode notification device (not shown) notify that effect. . These notification devices are lamps provided on the dashboard of the engine-equipped machine, and information is notified by lighting of the lamps. An indicator lamp, an LED, a liquid crystal display, an organic EL display, an alarm buzzer, or the like provided on these alarm device dashboards can be used. LED is a light-emitting diode, and EL is an abbreviation for electroluminescence.

In the limp home operation mode (S3) in which the reduced cylinder operation shown in FIG. 5 is performed under the control of the electronic control unit (4), the cylinder (C1) in which the combustion shown in FIGS. Ignition is performed at each crank angle. In this engine, ignition is performed every crank angle of 720 °.
For this reason, the explosion intervals are equal and vibration is reduced.

  The engine includes a rotation speed detection sensor (26) for detecting the engine rotation speed and a crank angle detection sensor (27) for detecting a crank angle. The electronic control unit (4) is a rotation speed detection sensor (26). Based on the detected engine speed, the intake air amount detected by the intake air amount detection device (3), and the crank angle detected by the crank angle detection sensor (27), the fuel injector (I1) of each cylinder (C1) (C2) ) (I2) is opened at a predetermined timing for a predetermined time, and a predetermined amount of fuel is injected into each cylinder (C1) (C2) at a predetermined timing, and at each predetermined timing, each cylinder (C1) (C2) is injected. Sparks are generated in the spark plugs (P1) and (P2).

  As shown in FIGS. 1 to 4, this engine is a two-cylinder engine. In the limp home operation mode (S3) in which the reduced cylinder operation shown in FIG. 5 is performed under the control of the electronic control unit (4), 1, only one specific cylinder (C1) shown in FIG. 3 is combusted, and the other cylinder (C2) is stopped.

As shown in FIGS. 1 to 4, this engine is an air-cooled engine, and in the limp home operation mode (S3) in which the reduced-cylinder operation shown in FIG. 5 is performed under the control of the electronic control unit (4), FIG. Only the combustion of the first cylinder (C1) on the ventilation upstream side shown in FIG. 2 is performed, and the combustion of the second cylinder (C2) on the ventilation downstream side is stopped.
For this reason, the engine air cooling efficiency in the limp home operation mode (S3) is high.

In the limp home operation mode (S3) in which the reduced cylinder operation shown in FIG. 5 is performed under the control of the electronic control unit (4) shown in FIG. 1, the cylinder (C2) shown in FIGS. In addition to stopping the fuel injection, spark generation from the spark plug (P2) in the cylinder (C2) is also stopped.
For this reason, generation | occurrence | production of a useless spark is stopped and durability of a spark plug (P2) increases.

  In this embodiment, the spark plug (P1) of the first cylinder (C1) in which combustion is performed in the reduced cylinder operation in the limp home operation mode (S3) is the first spark plug, and the second cylinder (C2) in which combustion is stopped. ) Spark plug (P2) is a second spark plug.

  In the limp home operation mode (S3) in which the reduced cylinder operation shown in FIG. 5 is performed under the control of the electronic control unit (4), only the combustion in the second cylinder (C2) on the downstream side of the ventilation shown in FIG. You may comprise so that combustion of the 1st cylinder (C1) of the ventilation upstream side may be stopped.

The flow of control by the electronic control unit (4) in this embodiment is as follows.
As shown in FIG. 5, in step (S1), it is determined whether or not an engine abnormality detection condition is satisfied. If the determination is affirmative, the process proceeds to step (S2).
In step (S2), it is determined whether or not the conditions for setting the limp home operation mode are satisfied. If the determination is affirmative, the process proceeds to step (S3).
In step (S3), the engine operation mode is changed to the limp home operation mode, the reduced cylinder operation is performed, and the process returns to step (S1).

If the determination in step (S1) is negative, the process proceeds to step (S4).
In step (S4), the engine operation mode is set to the normal operation mode, all-cylinder operation is performed, and the process returns to step (S1).
If the determination in step (S2) is negative, the process proceeds to step (S5).
In step (S5), it is determined whether or not the engine stop condition is satisfied. If the determination is affirmative, the process proceeds to step (S6).
In step (S6), engine stop processing is performed, and control is terminated.
If the determination in step (S5) is negative, that is, if the warning processing condition is satisfied, the process proceeds to step (S7).
In step (S7), warning processing is performed, and the process proceeds to step (S4).

  (1) ... Throttle valve, (2) ... Mechanical governor, (3) ... Intake amount detection device, (I1) ... First fuel injector, (I2) ... Second fuel injector, (4) ... Electronic control device, 5) ... Abnormality detection device, (5a) ... Engine wall temperature detection sensor, (5b) ... Cooling air temperature detection sensor, (5c) ... Oil temperature detection sensor, (5d) ... Intake temperature detection sensor, (5e) ... Hydraulic pressure Detection sensor, (C1) ... first cylinder, (C2) ... second cylinder, (S3) ... limp home operation mode, (P2) ... second spark plug.

Claims (6)

Detected by throttle valve (1), mechanical governor (2) for controlling throttle valve (1), intake air amount detection device (3), fuel injectors (I1) (I2), and intake air amount detection device (3) In a spark ignition type multi-cylinder engine having an electronic control unit (4) for controlling the fuel injection amount from the fuel injectors (I1) and (I2) according to the intake air amount,
An abnormality detection device (5) for detecting engine abnormality is provided, and the operation control mode is set to the limp home operation mode (S3) in the electronic control device (4) based on the predetermined abnormality detection by the abnormality detection device (5). In the limp home operation mode (S3), only the combustion of the specific cylinder (C1) is performed, the fuel injection by the fuel injector (I2) to the other cylinder (C2) is stopped, and the cylinder (C2) A spark-ignition multi-cylinder engine configured to perform a reduced-cylinder operation in which combustion is stopped. The spark ignition type multi-cylinder engine according to claim 1,
The abnormality detection device (5) includes an engine temperature detection sensor (5a) for detecting engine wall temperature, a cooling air temperature detection sensor (5b) for detecting engine cooling air temperature, and an oil temperature detection sensor (5) for detecting engine oil temperature. 5c) one or more sensors including an intake air temperature detection sensor (5d) for detecting the intake air temperature and a hydraulic pressure detection sensor (5e) for detecting the circulating oil pressure of the engine oil,
A spark ignition type multi-cylinder engine characterized in that the predetermined abnormality is detected by the electronic control unit (4) based on detection by any one of the sensors. In the spark ignition type multi-cylinder engine according to claim 1 or 2,
In the limp home operation mode (S3) in which the reduced-cylinder operation is performed under the control of the electronic control unit (4), the cylinder (C1) in which combustion is performed is configured to be ignited at every equally spaced crank angle. A spark ignition type multi-cylinder engine characterized by that. In the spark ignition type multi-cylinder engine according to any one of claims 1 to 3,
In the limp home operation mode (S3), which is applied to a two-cylinder engine and under reduced cylinder operation under the control of the electronic control unit (4), only one specific cylinder (C1) is burned and the other cylinder is operated. A spark ignition type multi-cylinder engine configured to stop combustion in (C2). The spark ignition type multi-cylinder engine according to claim 4,
In the limp home operation mode (S3), which is applied to an air-cooled engine and is reduced in cylinder operation by the control of the electronic control unit (4), only the combustion of the cylinder (C1) on the upstream side of the ventilation is performed, and the downstream side of the ventilation is performed. A spark-ignition multi-cylinder engine configured to stop combustion of the cylinder (C2). In the spark ignition type multi-cylinder engine according to any one of claims 1 to 5,
In the limp home operation mode (S3) in which the reduced cylinder operation is performed under the control of the electronic control unit (4), in addition to stopping the fuel injection to the cylinder (C2) where the combustion is stopped, the cylinder (C2 The spark ignition type multi-cylinder engine is also configured to stop the generation of sparks from the spark plug (P2).

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