JP7163946B2 - Engine control device and engine control method - Google Patents

Description

TECHNICAL FIELD The present disclosure relates to an engine control device and a control method thereof, and more particularly to a control device and an engine control method for an engine having a pressure reducing device for improving startability.

In the past, in order to improve the startability of the engine, a pressure reducing device was installed near the exhaust valve of the engine. It made it easier to get over the point and ensured quick startability.

In addition, there is also a situation in which a decompression device is installed near the intake valve of the engine in order to improve the startability of the engine. In the compression stroke, the decompression device opens the intake valve to lower the compression torque, thereby ensuring quick startability.

The current industry practice is to inject fuel only by sensing the engine speed signal, and pay no attention to whether the pressure reducer is in working condition. However, if the exhaust valve or intake valve is opened during the compression stroke when the pressure reducing device is operating, the compression ratio in the cylinder will decrease. There is also the problem that it enters the atmosphere as a Further, when the compression ratio is lowered, the mixed gas cannot be sufficiently combusted, and incompletely combusted waste gas may enter the atmosphere during the exhaust stroke, resulting in deterioration of emissions. This is not in line with current stringent requirements for environmental protection in various countries.

Chinese Patent Application Publication No. 106014745

The present disclosure is intended to solve the above existing technical problems, and the object thereof is to provide an engine control device and an engine control method for an engine having a pressure reducing device to enhance startability. On the other hand, by reducing or prohibiting fuel injection within the rotational speed range in which the decompression device operates at startup, the mixed gas that was not burned during the compression stroke is discharged into the atmosphere via the exhaust pipe. The point is to reduce what is done.

An engine control device (2), which is one form of the present disclosure, is applied to a motorcycle (100). The motorcycle has an engine (4) and a motor-generator (5) as power sources, and further includes an engine rotation speed sensor (13) for detecting the rotation speed of the engine. The engine is provided with a decompression device (80). The pressure reducing device is an autocentrifugal type that operates in conjunction with the centrifugal force of the engine's camshaft rotating, opening the engine's exhaust or intake valves before the engine's crankshaft (44) reaches compression top dead center. It is a decompression device. The engine control device includes a decompression device operation determination unit that determines whether the decompression device is in the operation process, and if the decompression device operation determination unit determines that the decompression device is in the operation process, the amount of fuel injection is reduced or the fuel is injected. A fuel injection control unit for inhibiting injection , a fuel injection amount recovery control unit, and a decompression device operation determination unit determining that the decompression device is in the operation process, and the fuel injection control unit reducing fuel injection. Alternatively, when the fuel injection is prohibited and the rotational speed (NE3) cannot be reached within a predetermined period of time, the fuel injection amount recovery control unit immediately restores the normal fuel injection amount .

In the engine control device having this structure, when the decompression device is operating, fuel injection is reduced or prohibited with respect to the fuel injection amount, so that the insufficiently combusted mixed gas caused by the decrease in the compression ratio is reduced. It can be prevented from being discharged into the atmosphere through an open exhaust pipe, thereby ensuring startability of the engine and at the same time avoiding the occurrence of emission deterioration problem.

Preferably, the decompression device operation determination unit determines whether or not the decompression device is operating based on the detection result of the engine speed sensor, and the engine speed detected by the engine speed sensor reaches a predetermined speed ( NE3), the decompression device operation determination unit determines that the decompression device is in the process of being operated.

The predetermined rotation speed is set based on the upper limit value (NE1) of the engine rotation speed when the decompression device is in operation.

More preferably, the predetermined rotation speed is NE3=min(NE1, NE2), of which NE2 is the rotation speed of the engine when the engine is started only by the motor-generator without combustion of the fuel mixture gas. is the upper limit.

By doing so, the upper limit value of the decompression device operation and NE2, which is the upper limit value of the engine rotation speed when the engine is started only by the electric motor generator without burning the fuel mixture gas, are compared together. , NE1≧NE2, the predetermined rotation speed (NE3) can be reasonably set.

Preferably, the fuel injection control unit reduces the amount of fuel injection when the rotational speed of the engine detected by the engine rotational speed sensor is within the first predetermined range (N1). When the rotational speed of the engine detected by the engine rotational speed sensor is within the second predetermined range (N2), the fuel injection control unit prohibits fuel injection.

In this way, fuel efficiency can be maximized by reducing or inhibiting fuel injection within different appropriate rotational speed ranges.

By doing so, it is possible to prevent deterioration of the startability of the engine due to factors affecting the startability such as aging deterioration of the battery and aging of the throttle valve.

An engine control method, which is a second form of the present disclosure, is a control method executed by an engine control device (2), and the engine control device is applied to a motorcycle (100). The motorcycle has an engine (4) and a motor generator (5) as power sources, further includes an engine rotation speed sensor (13) for detecting the rotation speed of the engine, and the engine is provided with a decompression device (80). The pressure reducing device works with the centrifugal force of the rotating engine camshaft opening the engine exhaust or intake valves before the engine crankshaft (44) reaches compression top dead center. It is an automatic centrifugal decompression device. The engine control method includes a decompression device operation determination step for determining whether the decompression device is in the operation process, and in the decompression device operation determination step, if it is determined that the decompression device is in the operation process, fuel injection amount reduction control or a fuel injection control step of performing fuel injection prohibition control, further including a fuel injection amount recovery control step, in the decompression device operation determination step, it is determined that the decompression device is in the operation process, and in the fuel injection control step If the predetermined rotation speed (NE3) cannot be reached within a predetermined time while the fuel injection amount reduction control or the fuel injection prohibition control is being performed, the normal fuel injection amount is immediately restored by the fuel injection amount recovery control step. .

In the engine control method described above, the fuel injection amount is reduced or inhibited while the pressure reducing device is operating, so that the insufficiently combusted mixed gas caused by the decrease in the compression ratio flows through the open exhaust pipe. As a result, it is possible to prevent the exhaust gas from being discharged into the atmosphere, ensuring the startability of the engine and at the same time avoiding the problem of worsening emissions.

The above and other objects, features and advantages of the present disclosure can be made more apparent with reference to the drawings and the following detailed description. The drawings are as follows.
1 is a configuration diagram of a vehicle to which an engine control device having an embodiment of the present disclosure is applied; FIG. 1 is a structural schematic diagram of a vehicle to which an engine control device having an embodiment of the present disclosure is applied; FIG. 4 is a flow chart representing control steps of an engine control method in an embodiment of the present disclosure; FIG. 4 is a diagram showing a rotation speed range during operation of the decompression device; FIG. 4 is a diagram representing the rotation speed range of the starting device; It is a figure showing the approximate structure of a decompression device.

In this embodiment, a motorcycle will be described as an example of the vehicle 100 . The vehicle 100 has an engine 4 and a motor generator 5 as power sources. In addition, a decompression device 80 is installed near an exhaust valve or an intake valve of the engine 4 in order to improve startability of the engine 4 .

First, the structure and operation of the decompression device 80 will be briefly described with reference to FIG.

The decompression device 80 is, for example, an automatic centrifugal decompression device 80 . The automatic centrifugal decompression device 80 reduces compression torque by opening an exhaust valve 86 near the top dead center of compression by a decompression cam 87 that operates in accordance with the centrifugal force of rotation of the camshaft 110 . In other words, the automatic centrifugal decompression device that does not require the operation of the passenger can improve the startability of the engine even if the swingback control is not performed.

The configuration of the decompression cam 87 is as follows. During operation, a curved operating surface 87 a formed on the decompression cam 87 contacts a slipper 85 provided on the rocker arm 81 . A slipper surface 85a of the slipper 85 is curved. In a situation where there is no centrifugal force on the camshaft 110 , the working surface 87 a abuts the slipper surface 85 a of the slipper 85 . At this time, since the operating surface 87a is higher than the cam spine 110a, the rocker arm 81 is lifted and the exhaust valve 86 can be opened even near the top dead center of the compression stroke.

The inventor of the present application believes that if the exhaust valve 86 is opened near the top dead center of the compression stroke, the compression ratio in the cylinder will decrease, and if the exhaust valve is opened during the compression stroke, the mixed gas will flow through the exhaust pipe. It was noted that the problem of worsening emissions was caused by entering the atmosphere through the air. Further, when the compression ratio is lowered, the mixed gas cannot be sufficiently combusted, and incompletely combusted waste gas may enter the atmosphere during the exhaust stroke, resulting in deterioration of emissions. In order to solve these problems, the inventors of the present application focused on the operation of the decompression device, and as a result of earnest research, finally realized the present disclosure.

An engine control device and an engine control method according to embodiments of the present disclosure will be described below with reference to the drawings.

FIG. 1 is a configuration diagram of a vehicle to which an engine control device having an embodiment of the present disclosure is applied. FIG. 2 is a structural schematic diagram of a vehicle to which an engine control system having an embodiment of the present disclosure is applied.

As shown in FIGS. 1 and 2, the vehicle 100 includes an input section 1, an engine control device (hereinafter abbreviated as "engine ECU") 2, and an output section 3. As shown in FIGS.

The input unit 1 turns on or off a storage battery (not shown in the figure) of the vehicle according to a driver's operation (power on/off). The input unit 1 includes a vehicle power switch 11 that outputs a signal for turning on or off the electric power of the motor generator 5 to the engine ECU 2 . The input unit 1 is provided in the cylinder body of the engine 4 and includes an engine temperature sensor 12 that detects the temperature of the engine 4 and outputs the detection result to the engine ECU 2 . The input unit 1 is provided in the cylinder body of the engine 4 or the stator of the motor generator 5, detects the rotational position of the crankshaft of the engine 4 and the rotational speed NE of the engine, and outputs the detection result to the engine ECU 2. A rotational speed sensor 13 is included. The input unit 1 is provided on the throttle valve 16 in the intake pipe 6 and includes a throttle valve position sensor 14 for detecting the opening degree of the throttle valve 16 . The input unit 1 is provided near the throttle valve 16 in the intake pipe 6 and is provided with an intake air temperature sensor 15 for detecting the intake air temperature. to the engine ECU 2 (hereinafter abbreviated as "MAP sensor").

The engine ECU 2 is a so-called microcomputer including a CPU, ROM, RAM, interface and the like. The engine ECU 2 is connected via an interface to a storage battery, a vehicle power switch 11 operated by the driver, various sensors including an engine temperature sensor 12 and an engine rotation speed sensor 13, a motor generator 5, a fuel pump 8, a fuel injection 41 and the like, and can receive and transmit information through a communication network such as CAN. The engine ECU 2 reads a program stored in a semiconductor memory so that the CPU executes processing defined by program code. The ECU performs signal transmission with external devices through I/O. The ECU performs predetermined processing based on the signal input through the I/O and outputs a signal representing the execution result. Thereby, the engine ECU 2 provides a predetermined control function. Also, the method of providing the function is not limited to the above method using software. Other provision methods may utilize, for example, hardware that uses open circuits, such as ICs and logic circuits.

The engine ECU 2 controls the motor generator 5, the fuel pump 8, the fuel injector 41, the fuel injector 41, the motor generator 5, the fuel pump 8, the fuel injector 41, and the like based on the outputs of various sensors including the engine temperature sensor 12 and the engine rotation speed sensor 13, and the state of the vehicle power switch 11. It controls the operation of each part such as the spark plug 42 .

The output unit 3 includes a motor generator 5 , which will be described later, and a fuel pump 8 that supplies fuel from the oil tank to the fuel injector 41 . The output unit 3 is provided near the cylinder body of the engine 4 on the intake pipe 6, and injects the fuel supplied from the fuel pump 8 into the cylinder of the engine 4 based on the command from the engine ECU 2. container 41 is included. The output unit 3 includes a spark plug 42 that burns the fuel injected into the cylinder of the engine 4 by igniting based on a command from the engine ECU 2 .

The motor generator 5 is a so-called ACG starter that also serves to start a motor and an AC generator (alternating current generator). The electric motor-generator 5 and the crankshaft 44 of the engine 4 are connected in a manner that does not interrupt the transmission of the rotational driving force. In other words, it is a system in which rotational driving force is always transmitted between the motor generator 5 and the crankshaft 44, and the rotor (not shown in the figure) of the motor generator 5 and the crankshaft 44 are directly connected ( fixed to one end of the crankshaft 44). The configuration of the motor generator 5 is as follows. When the engine 4 is started, the rotational driving force generated by the crankshaft 44 acts as a generator. Acts as a starter motor by being rotationally driven along the same or opposite direction.

The engine ECU 2 includes a decompression device operation determination section, and the decompression device operation determination section determines whether or not the decompression device is in the operation process based on parameters relating to the decompression device.

Here, the engine rotation speed will be described as an example of a parameter related to the decompression device.

For example, when the rotation speed NE of the engine 4 is detected by the engine rotation speed sensor 13, if the rotation speed NE of the engine 4 is smaller than a predetermined rotation speed NE3, the decompression device operation determination unit determines that the decompression device is in the operation process. do.

The predetermined rotation speed NE3 can be set based on the upper limit value NE1 of the engine rotation speed when the decompression device is in operation. Normally, NE3=NE1.

However, when the upper limit value NE1 when the decompression device is in operation is compared with the upper limit value NE2 of the engine rotation speed when the engine 4 is started only by the motor generator 5 without combusting the fuel mixture gas. , NE1≧NE2, it is desirable to calculate NE3 based on the following formula (1).

NE3=min(NE1, NE2) (1)
FIG. 4 is a diagram showing the rotation speed range during operation of the decompression device. FIG. 5 is a diagram showing the rotation speed range of the starter. The values of NE1 and NE2 can be set to different values depending on the difference in vehicle engine standards.

In addition, as a factor affecting the magnitude of NE2, NE2 also changes depending on the difference in the usage environment of the vehicle, as shown in FIG. For example, NE2 is affected by engine temperature, throttle valve opening, battery voltage, temperature characteristics of the magnetic material of the motor-generator 5, and oil viscosity. NE2 increases as the engine temperature increases, and NE2 decreases as the oil viscosity increases.

For example, if NE1=1200 rpm and NE2=1400 rpm for a 4-cycle motorcycle, then NE3=min(NE1, NE2)=1200 rpm.

The engine ECU 2 further includes a fuel injection control section, and when the decompression device operation determination section determines that the decompression device is in the operation process, the fuel injection control section reduces or prohibits fuel injection.

When the rotation speed of the engine 4 detected by the engine rotation speed sensor 13 is within the first predetermined range N1, the fuel injection control section reduces the amount of fuel injection. As an example, the first predetermined range N1 is 500 rpm to 1200 rpm.

燃料噴射減少量＝通常の燃料噴射量×減量基準値 During the fuel injection amount reduction control, the amount reduction reference value is calculated based on Table 1 below.

Fuel injection reduction amount = normal fuel injection amount x reduction reference value

Further, when the rotational speed of the engine 4 detected by the engine rotational speed sensor 13 is within the second predetermined range N2, the fuel injection control section prohibits fuel injection. As an example, the second predetermined range N2 is 0 rpm to 500 rpm.

The engine control system described in the above embodiments has the following beneficial effects.

(1) By reducing or inhibiting fuel injection with respect to the fuel injection amount when the pressure reducing device is operating, the exhaust pipe with insufficient combustion caused by the decrease in the compression ratio is opened. It is possible to prevent the exhaust gas from being discharged into the atmosphere through the air, thus ensuring the startability of the engine and at the same time avoiding the occurrence of the emission deterioration problem.

(2) Fuel efficiency is maximized by reducing or inhibiting fuel injection within different appropriate rotational speed ranges.

In addition, preferably, the engine ECU 2 further includes a fuel injection amount recovery control section in consideration of aging deterioration of the battery, aging of the throttle valve, etc., and the fuel injection control section reduces or prohibits fuel injection. If the normal rotation speed, for example, NE3, cannot be restored within a predetermined time t, the fuel injection amount recovery control unit immediately restores the normal fuel injection amount.

The predetermined time t is set, for example, to around 5 seconds based on the user's tolerance for the startup time.

In addition to the effects (1) and (2) above, the engine control device described in the above embodiment also has the following beneficial effects.

(3) It is possible to prevent deterioration of the startability of the engine due to factors affecting the startability, such as aging deterioration of the battery and aging of the throttle valve.

Next, an engine control method according to an embodiment of the present disclosure will be described with reference to FIG.

FIG. 3 is a flow chart representing control steps of an engine control method in an embodiment of the present disclosure.

First, in step S<b>1 , the engine ECU 2 determines whether or not the driver has started the engine based on the voltage level of the triode connected to the vehicle power switch 11 . When the vehicle power switch 11 is on, the engine ECU 2 is electrically connected to the storage battery, the triode connected to the vehicle power switch 11 of the engine ECU 2 outputs a high voltage level, and the engine ECU 2 causes the driver to start the engine. I judge. When the vehicle power switch 11 is off, the triode connected to the vehicle power switch 11 of the engine ECU 2 grounds and outputs a low voltage level, and the engine ECU 2 determines that the driver is not performing the engine start operation.

Subsequently, in step S2, the engine ECU 2 determines whether or not the detection result of the engine rotation speed sensor 13, that is, the rotation speed of the engine 4 is below NE3. If the rotation speed of the engine 4 is lower than NE3 (S2: YES), the process proceeds to step S4, and if the rotation speed of the engine 4 is NE3 or higher (S2: NO), the process proceeds to step S3. The setting of NE3 is as described above.

In step S3, the engine ECU 2 executes normal fuel injection amount control, and the fuel injector 41 injects a normal fuel injection amount of fuel into the cylinder of the engine 4 for normal combustion.

In step S4, the engine ECU 2 determines whether or not the detection result of the engine rotation speed sensor 13, that is, the rotation speed of the engine 4 is within the first predetermined range N1. If the rotation speed of the engine 4 is within the first predetermined range N1, the process proceeds to step S5, and if the rotation speed of the engine 4 is not within the first predetermined range N1, the process proceeds to step S6.

In step S5, the engine ECU 2 executes fuel injection amount reduction control, and the fuel injector 41 injects the reduced injection amount of fuel into the cylinder of the engine 4 to perform combustion with the reduced fuel injection amount.

In step S<b>6 , the engine ECU 2 executes fuel injection prohibition control to prohibit the fuel injector 41 from injecting fuel into the cylinder of the engine 4 .

Preferably, the engine ECU 2 further executes fuel injection amount recovery control, and recovers the normal rotation speed, for example, NE3 within a predetermined time t while executing the fuel injection amount reduction control or the fuel injection prohibition control. If not, the engine ECU 2 immediately restores the normal fuel injection amount.

The predetermined time t is set, for example, to around 5 seconds based on the user's tolerance for the startup time.

The engine control methods described in the above embodiments have the following beneficial effects.

(1) By reducing or inhibiting fuel injection with respect to the fuel injection amount when the pressure reducing device is operating, the exhaust pipe with insufficient combustion caused by the decrease in the compression ratio is opened. It is possible to prevent the exhaust gas from being discharged into the atmosphere through the air, thus ensuring the startability of the engine and at the same time avoiding the occurrence of the emission deterioration problem.

(2) Fuel efficiency is maximized by reducing or inhibiting fuel injection within different appropriate rotational speed ranges.

(3) It is possible to prevent deterioration of the startability of the engine due to factors affecting the startability, such as aging deterioration of the battery and aging of the throttle valve.

Although the present disclosure has been described with reference to examples, it should be understood that the present disclosure is not limited to the examples and structures described above. This disclosure also includes various modifications and changes within equivalents. In addition, various combinations and means, including one element, one or more or less than one other combinations and means, also fall within the category and conceptual scope of the present disclosure.

In the above embodiment, the engine ECU 2 determines whether or not the driver has started the engine based on the voltage level of the triode connected to the vehicle power switch 11 . However, the parameters for determining the engine starting operation are not limited to these.

For example, in the case of an engine having an idling stop function, it is possible to determine whether or not the driver has started the engine based on the opening of the throttle valve. If the opening of the throttle valve exceeds a predetermined threshold value, it is determined that the driver has started the engine.

In the above embodiment, the engine rotation speed is used as an example of the parameter related to the operation of the decompression device. However, the parameter related to the speed reduction device, that is, the parameter for determining whether the pressure reducing device is in the operation process is not limited to the rotational speed of the engine.

For example, a sensor for detecting the operating state of the decompression device can be installed directly.

Further, in the above-described embodiment, the engine ECU 2 determines whether or not to perform fuel injection amount reduction control or fuel injection prohibition control based on NE3. However, the upper limit value of the rotational speed of the engine for executing the fuel injection amount reduction control and the fuel injection prohibition control is not limited to NE3, and may be a rotational speed lower than NE3. In other words, even if the rotation speed is lower than NE3, the normal fuel injection amount is restored, thereby enhancing the startability of the engine.

Further, in the above embodiment, the engine ECU 2 determines NE2 based on FIG. However, the engine ECU 2 can also calculate NE2 by referring to a mapping diagram such as a map (throttle valve opening, voltage) based on the usage environment of the vehicle. In a state where fuel injection is prohibited, the engine ECU 2 can also prohibit ignition of the spark plug 42 .

The execution order of each process such as operation, order, step, stage, etc. in the devices, systems, programs and means shown in the claims, specification and drawings is "before", "before", etc. is not particularly explicit, and may be achieved in any order as long as the output of previous processing is not used in subsequent processing. Regarding the flow of operations in the claims, specification and drawings, ``first'' and ``followed'' are used for ease of explanation, but it means that they must be performed in that order. is not.

100 VEHICLE 1 INPUT UNIT 2 ENGINE ECU
3 Output Part 4 Engine 5 Motor Generator 6 Intake Pipe 8 Fuel Pump 11 Vehicle Power Switch 12 Engine Temperature Sensor 13 Engine Speed Sensor 14 Throttle Valve Position Sensor 15 Intake Temperature Sensor 16 Throttle Valve 17 Intake Pressure Sensor 41 Fuel Injector 42 Ignition Plug 44 Crankshaft 80 Pressure reducing device

Claims (2)

An engine control device (2) applied to a motorcycle (100), comprising:
The motorcycle has an engine (4) and a motor generator (5) as power sources,
further comprising an engine rotation speed sensor (13) for detecting the rotation speed of the engine;
The engine is provided with a decompression device (80),
The pressure reducing device works with the centrifugal force of the rotating camshaft of the engine opening the exhaust or intake valves of the engine before the crankshaft (44) of the engine reaches compression top dead center. In the engine control device, which is an automatic centrifugal decompression device,
a decompression device operation determination unit that determines whether the decompression device is in an operation process;
a fuel injection control unit that reduces or prohibits fuel injection when the decompression device operation determination unit determines that the decompression device is in an operation process;
including
further including a fuel injection amount recovery control unit,
In a state in which the decompression device operation determination unit determines that the decompression device is in the operation process and the fuel injection control unit is reducing the amount of fuel injection or inhibiting fuel injection, a predetermined rotation speed ( An engine control device , wherein if NE3) cannot be reached, the fuel injection amount recovery control unit immediately restores the normal fuel injection amount . An engine control method executed by an engine control device (2),
The engine control device is applied to a motorcycle (100), the motorcycle has an engine (4) and a motor generator (5) as power sources,
further comprising an engine rotation speed sensor (13) for detecting the rotation speed of the engine;
The engine is provided with a decompression device (80),
The pressure reducing device operates with the centrifugal force of the rotating camshaft of the engine opening the exhaust or intake valves of the engine before the crankshaft (44) of the engine reaches compression top dead center. In the engine control method, which is an automatic centrifugal decompression device,
a decompression device operation determination step of determining whether the decompression device is in an operation process;
a fuel injection control step of performing fuel injection reduction control or fuel injection prohibition control when it is determined in the decompression device operation determination step that the decompression device is in the operation process ,
further including a fuel injection amount recovery control step;
In the decompression device operation determination step, it is determined that the decompression device is in the operation process, and in a state in which fuel injection amount reduction control or fuel injection prohibition control is being performed in the fuel injection control step, a predetermined rotation speed is reached within a predetermined time. An engine control method , wherein if (NE3) is not reached, the fuel injection amount is immediately restored to a normal amount by the fuel injection amount recovery control step .

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