JP2022166678A - Engine and control device and method thereof - Google Patents

Abstract

To suppress variation in air-fuel mixture concentration in a combustion chamber at the time of starting an engine.SOLUTION: An engine includes: an engine body that has a cylinder, a piston reciprocating in the cylinder, a crank shaft rotating by interlocking with the reciprocating of the piston, and a valve train that performs intake action into the cylinder and exhaust action by interlocking with the reciprocating of the piston; a fuel injection valve that injects a fuel; an ignition device that ignites the fuel in the cylinder; and a control device for controlling the fuel injection valve and the ignition device, which executes a stand-by processing of maintaining a state of stopping fuel injection since a starting is determined until it is determined that the exhaust action by the valve train is executed when a predetermined stand-by condition is satisfied, controls the fuel injection valve to inject a fuel, and control the ignition device to execute a start combustion processing for igniting the fuel in the cylinder when the stand-by processing is finished.SELECTED DRAWING: Figure 3

Description

This disclosure relates to techniques for starting an engine.

Patent Literature 1 discloses performing control to adjust the opening of a throttle valve when the engine is started.

JP 2019-044621 A

When the engine is started, the concentration of the air-fuel mixture in the combustion chamber may vary depending on the fuel remaining in the combustion chamber.

Accordingly, an object of the present disclosure is to suppress variations in the concentration of the air-fuel mixture in the combustion chamber when the engine is started.

In order to solve the above problems, an engine includes a cylinder, a piston that reciprocates within the cylinder, a crankshaft that rotates in conjunction with the reciprocation of the piston, and a crankshaft that rotates in conjunction with the reciprocation of the piston. An engine body having a valve mechanism that performs intake operation and exhaust operation, a fuel injection valve that injects fuel, an ignition device that ignites the fuel in the cylinder, and the fuel injection valve and the ignition device. A control device for controlling, when a predetermined standby condition is satisfied, performs standby processing for maintaining a state in which fuel injection is stopped from when it is determined that the engine starts to start until it is determined that the exhaust operation by the valve mechanism has been executed. and a control device for executing starting combustion processing for controlling the fuel injection valve to inject fuel and controlling the ignition device to ignite the fuel in the cylinder when the standby processing is finished.

According to this engine, the fuel injection is stopped during the execution of the standby process after starting the engine. As a result, in the standby process, the unburned gas remaining in the cylinder is discharged by the exhaust operation of the valve mechanism caused by the reciprocation of the piston. In a state in which the subsequent starting combustion process is executed, fuel combustion is executed in a state in which residual unburned gas in the cylinder is exhausted. By discharging the remaining unburned gas before starting in this manner, the influence of the remaining unburned gas can be suppressed, and variations in the concentration of the air-fuel mixture in the combustion chamber when the engine is started can be suppressed.

Further, the engine control device is an engine control device that controls a fuel injection valve and an ignition device in the engine, and is characterized by: (a) when a predetermined standby condition is satisfied, it is determined that the start-up is to be started, and then the valve mechanism is operated; (b) when the standby process is completed, the fuel injection valve is controlled to inject fuel, and the ignition device is turned on; and a starting combustion process for controlling and igniting the fuel in the cylinder.

According to this engine control device, the fuel injection is stopped during the execution of the standby process after starting the engine. As a result, in the standby process, the unburned gas remaining in the cylinder is discharged by the exhaust operation of the valve mechanism caused by the reciprocation of the piston. In a state in which the subsequent starting combustion process is executed, fuel combustion is executed in a state in which residual unburned gas in the cylinder is exhausted. By discharging the remaining unburned gas before starting in this way, the influence of the remaining unburned gas is suppressed in the engine to be controlled, and variations in the air-fuel mixture concentration in the combustion chamber when the engine is started are suppressed. be able to.

Further, the engine control method is a method of controlling a fuel injection valve and an ignition device in the engine, and comprises: (a) when a predetermined standby condition is satisfied, it is determined that the start-up is to be started, and then the valve mechanism is operated; (b) when the process (a) is completed, the fuel injection valve is controlled to inject fuel, and the ignition device and a process of controlling to ignite the fuel in the cylinder.

According to this engine control method, the fuel injection is stopped during the execution of the standby process after starting the engine. As a result, in the standby process, the unburned gas remaining in the cylinder is discharged by the exhaust operation of the valve mechanism caused by the reciprocation of the piston. In a state in which the subsequent starting combustion process is executed, fuel combustion is executed in a state in which residual unburned gas in the cylinder is exhausted. By discharging the remaining unburned gas before starting in this way, the influence of the remaining unburned gas is suppressed in the engine to be controlled, and variations in the air-fuel mixture concentration in the combustion chamber when the engine is started are suppressed. be able to.

It is possible to suppress variations in the concentration of the air-fuel mixture in the combustion chamber when the engine is started.

1 is a schematic diagram showing an engine according to an embodiment; FIG. 2 is a block diagram showing the electrical configuration of the engine; FIG. 4 is a flowchart showing an example of processing by a control device; 4 is a timing chart showing processing timings of each part of the engine when standby processing is performed; FIG. 5 is an explanatory diagram showing the operation of movable parts of the engine when standby processing is performed;

Hereinafter, an engine, its control device, and method according to an embodiment will be described. FIG. 1 is a schematic diagram showing an engine 20 according to an embodiment. The engine 20 is a machine powered by combustion of fuel. The engine 20 may be used as a power source for a vehicle, or may be used as a power source for a mechanical device. The vehicle may be a straddle-type vehicle such as a motorcycle, a tricycle, an ATV (All Terrain Vehicle), or a personal watercraft, or may be a vehicle such as a large riding lawn mower.

The engine 20 includes an engine body 30 , a fuel injection valve 50 , an ignition device 52 and a control device 60 .

The engine body 30 is a mechanical structural part that generates mechanical energy from combustion gases. The fuel injection valve 50 is a valve that supplies fuel to the engine body 30 . The ignition device 52 is a device for igniting fuel in the engine body 30 . The control device 60 controls the fuel injection timing by the fuel injection valve 50, the ignition timing by the ignition device 52, and the like, according to the cycle of the engine.

The engine 20 is started by igniting the fuel supplied from the fuel injection valve 50 to the engine body 30 by the ignition device 52 . However, depending on the start-up environment of the engine 20 and the like, the air-fuel mixture concentration may deviate from the range suitable for combustion due to the influence of unburned gas remaining in the engine body 30 and the like. Therefore, in such a starting environment, the fuel injection by the fuel injection valve 50 is stopped from when it is determined that the engine 20 has started to start until it is determined that the exhaust operation has been performed. As a result, the influence of residual unburned gas is eliminated, and the air-fuel mixture concentration in the engine body 30 is reset to be as lean as possible. Thereafter, the fuel is supplied from the fuel injection valve 50 to the engine body 30 and is ignited by the ignition device 52 . Therefore, the fuel is ignited with a mixture concentration suitable for combustion, and the engine can be started smoothly.

A more specific example will be described. The engine body 30 includes a cylinder 33 , a piston 34 , a crankshaft 40 and a valve mechanism 46 .

The cylinder 33 is a tubular portion formed in the main body 32 that serves as the base of the engine main body 30 . The main body 32 is a part that forms a combustion chamber, a space in which the piston 34 moves, a space in which the crankshaft rotates, and the like. For example, the main body 32 is configured by combining a cylinder head, a cylinder block, a crankcase, and an oil pan in order from top to bottom. A cylinder 33 is formed in the cylinder block. The cylinder 33 is a part forming a cylindrical space in which the piston 34 moves, forming a combustion chamber. By combining the cylinder head on the cylinder block, the upper opening of the cylinder 33 is closed by the cylinder head. A space in which the crankshaft 40 rotates is formed on the opposite side of the cylinder 33 from the cylinder head by assembling the crankcase under the cylinder block. Oil that circulates within the engine 20 is stored in an oil pan that is combined under the crankcase. The number of cylinders 33 is not particularly limited, and may be one cylinder, two cylinders, or a larger number of cylinders.

The piston 34 is a member that is arranged in the cylinder 33 so as to be reciprocally movable in a state in which a space on the one end side and a space on the other end side of the cylinder 33 are separated from each other. The movement of the piston 34 within the cylinder 33 enables compression, expansion, intake and exhaust in the space within the cylinder 33 .

The crankshaft 40 is rotatably arranged in a space opposite to the cylinder head with respect to the cylinder 33 . The rotation axis of the crankshaft 40 is set orthogonal to the reciprocating direction of the piston 34 . The crankshaft 40 includes a shaft 40a, a crank arm 40b and a crankpin 40c, and is rotatably supported by the main body 32. As shown in FIG. The rotation axis of the crankshaft 40 coincides with the central axis of the shaft 40a. The crank pin 40c is supported by the crank arm 40b at a position offset from the axis of rotation of the shaft 40a. As the crankshaft 40 rotates, the crankpin 40 c rotates around the rotation axis of the crankshaft 40 . A connecting rod 38 connects the piston 34 and the crankpin 40c. The reciprocating motion of the piston 34 is transmitted as rotary motion to the crankshaft 40 via the connecting rod 38 . Also, the rotational motion of the crankshaft 40 is transmitted to the piston 34 as reciprocating motion via the connecting rod 38 . That is, the crankshaft 40 can rotate in conjunction with the reciprocating movement of the piston 34 . The crank arm 40b and the crank pin 40c are provided according to the number of cylinders.

The valve mechanism 46 performs an intake operation into the cylinder 33 and an exhaust operation in conjunction with the reciprocating movement of the piston 34 . The valve mechanism 46 includes, for example, an intake valve 47 , an exhaust valve 48 , and a valve opening/closing unit 49 that opens and closes the valves 47 and 48 . The intake valve 47 and the exhaust valve 48 are provided in a portion that closes the upper opening of the cylinder 33, such as the cylinder head.

More specifically, an intake port is formed in a portion of the cylinder head that closes the upper opening of the cylinder 33, and an intake valve 47 is provided in the intake port. The intake port is connected to the outside air intake port via the intake port 47P and the like. Outside air is drawn into the cylinder 33 from the intake port 47P through the intake port. The intake valve 47 is supported so as to be displaceable between a closed position that closes the intake port and an open position that opens the intake port. Depending on the opening/closing position of the intake valve 47, the state is switched between a state in which outside air is taken into the cylinder 33 and a state in which the intake is suppressed. The intake port 47P is provided with an air supply amount adjusting device 47V including a throttle valve 47Va whose opening/closing is controlled according to the operation of the throttle. The throttle valve 47Va is, for example, a butterfly valve. The intake air amount into the cylinder 33 can be adjusted according to the opening/closing degree of the throttle valve 47Va.

An exhaust port is formed in a portion of the cylinder head that closes the upper opening of the cylinder 33, and an exhaust valve 48 is provided in the exhaust port. The exhaust port is connected to an external exhaust port via an exhaust port 48P or the like. The gas in the cylinder 33 is discharged from the exhaust port through the exhaust port 48P and the like. The exhaust valve 48 is supported so as to be displaceable between a closed position that closes the exhaust port and a closed position that opens the exhaust port. Depending on the opening/closing position of the exhaust valve 48, the gas in the cylinder 33 is switched between a state in which the gas in the cylinder 33 is discharged to the outside and a state in which the discharge is suppressed. Note that one cylinder 33 may have one intake port and intake valve, or may have a plurality of intake ports and intake valves. Similarly, one exhaust port and exhaust valve 48 may be provided for one cylinder 33, or a plurality thereof may be provided.

The valve opening/closing unit 49 includes, for example, a camshaft 49a, a rotation transmission mechanism 49b, and the like. The camshaft 49 a is rotatably supported on the side opposite to the cylinder 33 with respect to the intake valve 47 and the exhaust valve 48 . The camshaft 49 a has cam portions corresponding to the intake valve 47 and the exhaust valve 48 . For example, when the camshaft 49a rotates, the intake valve 47 and the exhaust valve 48, which are biased toward the open position by a spring or the like, reciprocate between the open position and the closed position. The rotation transmission mechanism 49b includes at least one of a chain, gears, etc., and transmits the rotational motion of the crankshaft 40 as force to rotate the camshaft 49a. That is, the crankshaft 40 rotates in conjunction with the reciprocating movement of the piston 34, the rotation of the crankshaft 40 is transmitted to the camshaft 49a by the rotation transmission mechanism 49b, and the camshaft 49a rotates. Rotation of the camshaft 49a moves the intake valve 47 and the exhaust valve 48 between the open position and the closed position. As a result, in conjunction with the reciprocating movement of the piston 34, an intake operation into the cylinder 33 and an exhaust operation are performed.

As described above, the number of cylinders 33 is arbitrary, and the cam portions corresponding to the intake valves 47 and the exhaust valves 48 are provided according to the number of cylinders. In the cylinder 33, the opening/closing timing of the intake valve 47 and the exhaust valve 48 with respect to the reciprocating movement of the piston 34 (rotation of the crankshaft 40) can be set by adjusting the transmission speed ratio (gear ratio, etc.) in the rotation transmission mechanism.

The fuel injection valve 50 is connected to a fuel tank that stores fuel, and injects fuel to supply the fuel to the cylinder 33 . The fuel may be injected into the intake port 47</b>P or directly into the cylinder 33 . FIG. 1 shows an example in which the fuel injection valve 50 is provided at a position within the intake port 47P to inject fuel to the downstream side of the throttle valve 47Va. The fuel injected from the fuel injection valve 50 is supplied into the cylinder 33 while being mixed with the outside air passing through the intake port 47P. The fuel is, for example, gasoline.

The ignition device 52 is a device that supplies ignition energy for igniting fuel in the cylinder 33 . For example, the ignition device 52 ignites the fuel in the cylinder 33 at a predetermined ignition timing with the voltage supplied from the high voltage circuit. The ignition device 52 is provided in a portion of the main body 32 that closes the upper opening of the cylinder 33, such as the engine head.

A control device 60 controls the fuel injection valve 50 and the ignition device 52 . Control device 60 may be configured by a computer that operates with power supplied from a battery provided in engine 20 . When the control device 60 satisfies a predetermined standby condition, the control device 60 waits to maintain a state in which the fuel injection by the fuel injection valve 50 is stopped from when it determines that the engine is started to when it determines that the exhaust operation by the valve mechanism 46 has been performed. Execute the process. When the standby process ends, the control device 60 controls the fuel injection valve 50 to inject fuel, and controls the ignition device 52 to ignite the fuel in the cylinder 33 for start-up combustion processing.

The engine 20 includes an operation unit such as a switch for starting the engine 20 , a starter motor, and a rotation detection device for detecting rotation of the crankshaft 40 .

Here, the engine 20 has a power switch 21 and a start switch 22 as operation units. The power switch 21 and the start switch 22 are provided on a housing that houses the engine 20, an operation panel for operating the engine 20, or the like. The power switch 21 and the start switch 22 are composed of push switches, rotary switches, touch switches, and the like. When the power switch 21 is turned on, the control device 60 and the like are energized, and the engine 20 is ready to start. When the start switch 22 is turned on, the engine 20 is started, and the reciprocating movement of the piston 34 and the rotation of the crankshaft 40 continue due to combustion of fuel. The power on/off operation of the engine 20 and the start operation of the engine 20 may be received by operating a mobile terminal device such as a mobile phone or a mobile key.

The starter motor 24 is an electric motor that rotates the crankshaft 40 when the engine 20 is started. The starter motor 24 rotates by being supplied with power from a separately provided battery. When starting the engine, the rotational motion of the starter motor 24 is transmitted to the crankshaft 40 via a starter one-way clutch or the like. When the engine 20 is started by combustion of fuel in the cylinder 33, the power transmission path from the crankshaft 40 to the starter motor 24 is cut off by the starter one-way clutch. This allows the crankshaft 40 to rotate and the engine 20 to continue operating regardless of whether the starter motor 24 is rotating or stopped.

The starter motor 24 may be omitted, and instead, the crankshaft may be rotated by force such as the user's foot operating the kick pedal or the user's hand operating the starting handle when starting the engine 20 .

The rotation detection device 26 is a sensor that detects rotation of the crankshaft 40 . For example, the rotation detection device 26 may detect rotation of a rotor 40R that rotates integrally with the crankshaft 40. FIG. More specifically, for example, the rotation detection device 26 may be a magnetic sensor. In this case, one or a plurality of magnetic protrusions 40Ra may be provided on a portion of the outer circumference of the rotor 40R to detect the rotation of the crankshaft 40 according to changes in the magnetic field accompanying the rotation of the crankshaft 40. The rotation detection device 26 may detect the rotation angle (crank angle) of the crankshaft 40 . For example, a plurality of protrusions 40Ra may be provided around the rotor 40R at a constant angle, and the rotation angle of the crankshaft 40 may be detected by detecting each protrusion 40Ra.

The rotation detection device 26 may not be a magnetic sensor, but may be an eddy current displacement sensor or an optical sensor. The rotation detection device 26 can directly or indirectly detect the rotation of the crankshaft 40. Therefore, the starter motor 24, the camshaft 49a, and the crankshaft 49a, which move in tandem with the crankshaft 40, are used. The rotation of the crankshaft 40 may be detected indirectly by detecting the rotation of the shaft or the like in the rotary motion transmission mechanism 40 .

The engine 20 may include a water temperature sensor 27 as an example of a temperature detector that detects the temperature of the engine 20 before fuel combustion in the cylinder 33 (see FIG. 2). A water temperature sensor 27 is a temperature sensor that detects the temperature of the coolant of the engine 20 . A water temperature sensor is provided somewhere along the way the coolant flows. Since the temperature of the coolant changes according to the temperature of the engine 20, the temperature of the engine 20 is detected by detecting the temperature of the coolant. It is not essential that the water temperature sensor 27 be the temperature detection unit, and the oil temperature sensor 28 may be the temperature detection unit. Oil temperature sensor 28 is a temperature sensor that detects the temperature of engine oil circulating in engine 20 . The oil temperature sensor 28 is provided, for example, at a position that detects the temperature of the engine oil stored in the oil pan.

FIG. 2 is a block diagram showing the electrical configuration of engine 20. As shown in FIG. As shown in the figure, the water temperature sensor 27, the rotation detector 26, the power switch 21, and the start switch 22 are connected to the control device 60, and detection signals or operation signals from them are given to the control device 60. The ignition device 52, the fuel injection valve 50, and the air supply amount adjustment device 47V are connected to the control device 60. The control device 60 controls the ignition timing of the ignition device 52, the fuel injection timing of the fuel injection valve 50, and the amount of air supply. The adjustment device 47V adjusts the intake air amount. The starter motor 24 may be on/off controlled by the start switch 22 via the controller 60 or may be turned on/off directly by the start switch 22 .

The control device 60 is configured by a computer including a processor 62 such as a CPU (Central Processing Unit), a storage unit 63, and the like. The storage unit 63 is configured by a non-volatile storage device such as an HDD (hard disk drive) or SSD (Solid-state drive). The storage unit 63 stores a program 63a, standby condition setting conditions 63b, and the like. The processor 62 performs processing according to a pre-stored program 63a to execute control processing for the engine 20, particularly processing for starting the engine 20, which will be described later. In other words, the program 63 a is a program for causing the control device 60 , which is a computer, to execute processing related to the control method of the engine 20 . The standby condition setting condition 63b defines a standby condition for executing standby processing. The standby condition in the standby condition setting condition 63b may be a condition set based on the temperature of the engine 20 before combustion. For example, a first threshold temperature assuming a hot start is set as the standby condition, and the standby condition is set to be satisfied when the detected temperature of the engine 20 exceeds or is equal to or higher than the first threshold temperature. good too. Further, for example, a second threshold temperature assuming a constant temperature environment lower than normal temperature is set as the standby condition, and when the detected temperature related to the engine 20 is lower than or equal to the second threshold temperature, the standby condition is set. May be set to meet. More specifically, a value of 40 degrees Celsius to 60 degrees Celsius (for example, 50 degrees) is set as the first threshold temperature, and a value of 10 degrees Celsius to −10 degrees Celsius (for example, 0 degrees) is set as the second threshold temperature. may be set. The processor 62, for example, compares the temperature based on the water temperature sensor 27 with the temperature defined in the standby condition setting condition, thereby determining whether or not the standby condition is satisfied. In the standby condition setting condition 63b, the exhaust operation completion condition may be associated with the standby condition. The exhaust operation completion condition is a condition for completing the exhaust operation after starting the exhaust operation without fuel injection. The exhaust operation completion condition may be defined by, for example, the number of revolutions of the crankshaft 40, or may be defined by time. More specifically, the exhaust operation completion condition may be defined by the rotation speed after the rotation of the crankshaft 40 is detected by the rotation detection device 26 after the start of the engine 20 is started.

FIG. 3 is a flowchart showing an example of processing by the control device 60. As shown in FIG.

When the power switch 21 is turned on, the control device 60 is activated and executes the process of step S1. The process of step S1 is a process of determining whether or not a predetermined waiting condition is satisfied. In this embodiment, in step S1, it is determined whether or not the hot start is performed as an example of the standby condition. A hot start is a start under temperature conditions higher than the temperature at which the engine 20 was left in the normal temperature environment. A hot start is, for example, when the engine 20 is restarted after being stopped and before being sufficiently cooled. The determination in step S1 is made, for example, by comparing the temperature of the engine 20 before combustion with the first threshold temperature specified in the standby condition setting condition 63b. The temperature of the engine 20 before combustion is, for example, the coolant temperature detected by the water temperature sensor 27 . A hot start is determined if the temperature of the coolant is greater than or equal to the first threshold temperature.

The temperature of the engine 20 before combustion is the temperature of a portion related to the temperature inside the cylinder 33 , for example, the portion having a temperature that exhibits a positive correlation with the temperature inside the cylinder 33 . The temperature associated with the engine 20 before such combustion need not be the temperature of the coolant. As the temperature of the engine 20 before combustion, for example, the temperature in any part of the main body 32 of the engine 20 may be detected, or the temperature of the engine oil circulated in the engine 20 may be detected, The intake air temperature in the air cleaner chamber may be detected. The first threshold temperature, the second threshold temperature, and the like are set to temperatures according to each detection portion of the cylinder 33 in the engine 20 .

If it is determined to be a hot start, the process advances to step S2 to set exhaust operation completion conditions for hot start. The exhaust operation completion condition is defined by, for example, a condition for when the first threshold temperature is exceeded or exceeded in the standby condition setting condition 63b, and the control device 60 refers to the standby condition setting condition 63b to perform the exhaust operation Completion conditions may be set. For example, the exhaust operation completion condition may be defined as N rotations of the crankshaft 40 . N may be one rotation, two rotations, or three or more rotations. As will be described later, assuming a four-stroke engine 20, N may be 2 or more. The set conditions are temporarily stored in the storage unit.

If it is determined in step S1 that the hot start is not performed, the process proceeds to step S11. The process of step S11 is a process of determining whether or not another predetermined waiting condition is satisfied. In the present embodiment, in step S11, as an example of the standby condition, it is determined whether or not the engine is started at a low temperature. The low temperature start is a start under temperature conditions lower than the temperature at which the engine 20 is left in the normal temperature environment. A low temperature start is, for example, a case where the engine 20 is started in a state where the engine 20 is exposed to an extremely cold environment. A cold start may be a start in an extremely cold environment. Incidentally, the extremely cold environment refers to an environment at such a low temperature that the fuel injection amount at room temperature does not stabilize the engine start. It also refers to an environment where the temperature is low enough to require adjustment of the fuel injection amount and intake air amount. Under such an environment, unvaporized fuel tends to accumulate in the cylinder, resulting in fluctuations in air-fuel mixture concentration. The determination in step S11 is made, for example, by comparing the temperature of the engine 20 before combustion with the second threshold temperature defined in the standby condition setting condition 63b, as in step S1. The temperature of the engine 20 before combustion may be the temperature of the engine oil detected by the water temperature sensor 27, or the temperature of other parts related to the temperature in the cylinder 33, as described above. good too.

If it is determined that the engine is started at a low temperature, the process advances to step S12 to set an exhaust operation completion condition for a low temperature start. The exhaust operation completion condition is defined by the rotation speed of the crankshaft 40 in the standby condition setting condition 63b as in step S2, and may be set by referring to the standby condition setting condition 63b. The rotation speed in this case may be the same as or different from the rotation speed defined as the exhaust operation completion condition for hot start. The set conditions are temporarily stored in the storage unit.

After step S2 and after step S12, the process proceeds to step S3. In other words, steps S2 and S12 are cases where a predetermined standby condition is satisfied, and in this case, the processes after step S3 are executed. In step S3, it is determined whether or not the start switch 22 has been turned on. The process of step S3 is repeated until the start switch 22 is turned on, and when the start switch 22 is turned on, the process proceeds to step S4. Note that when the start switch 22 is turned on, a rotation start signal is given to the starter motor 24, and the starter motor 24 rotates. As the starter motor 24 rotates, the crankshaft 40 rotates, and the piston 34 reciprocates in conjunction with the rotation.

In step S<b>4 , the control device 60 detects whether or not the crankshaft 40 is rotating based on the output from the rotation detecting device 26 . When it is detected that the crankshaft 40 is rotating for the first time, it is determined that the engine is to start, and the process proceeds to step S5.

In step S5, control device 60 adds 1 to a count variable indicating the number of revolutions of crankshaft 40 (increment processing). After that, the process proceeds to step S6.

In step S6, the control device 60 causes the ignition device 52 to perform an ignition operation. The ignition operation is an operation of igniting the fuel inside the cylinder 33 during the combustion stroke of the engine 20 . For example, the control device 60 causes the ignition device 52 to perform an ignition operation at timing synchronized with the rotation angle of the crankshaft 40 detected by the rotation detection device 26 .

In the next step S7, it is determined whether or not an exhaust operation completion condition is satisfied. For example, if the exhaust operation completion condition is defined by the rotation speed of the crankshaft 40, the count variable incremented in step S5 and the exhaust operation set for hot start or cold start in step S2 or step S12 By comparing with the completion determination condition, it is determined whether or not the exhaust operation completion condition is satisfied. That is, the timing at which the exhaust operation ends is determined based on the detection result of the rotation detection device 26 . For example, when the exhaust operation completion condition is set to two rotations of the crankshaft 40, the number of rotations of the crankshaft 40 is two or more (the number of times the protrusion 40Ra of the rotor 40R is detected is three or more). ), it may be determined that the exhaust operation completion condition is satisfied. That is, when the crankshaft 40 rotates at a number of revolutions equal to or greater than the exhaust operation completion condition, it is found that the piston 34 has reciprocated a predetermined number of times or more with the rotation of the crankshaft 40 . If the piston 34 has reciprocated a predetermined number of times, it can be determined that the exhaust operation by the valve mechanism 46 has been completed. Therefore, it is determined whether or not the exhaust operation completion condition is satisfied based on the rotational speed of the crankshaft 40 . If it is determined in step S7 that the exhaust operation completion condition is not satisfied, the process returns to step S4 to repeat the processes of steps S4, S5, and S6. Therefore, the count variable is incremented each time the crankshaft 40 rotates. If it is determined in step S7 that the exhaust operation completion condition is satisfied, the process proceeds to step S8.

The processes of steps S4, S5 and S6 are repeated until it is determined in step S7 that the exhaust operation completion condition is satisfied. During this process, the control device 60 keeps the fuel injection by the fuel injection valve 50 stopped. In this series of processes, it is assumed that the crankshaft 40 rotates the number of times specified in the exhaust operation completion condition after the initial rotation of the crankshaft 40 is detected and the exhaust operation by the valve mechanism 46 is executed. This is an example of standby processing for maintaining a state in which fuel injection is stopped until determination is made. In this embodiment, the ignition operation is performed in the standby process (see step S6). However, the process of step S6 may be omitted and the ignition operation may be stopped in the standby process.

In step S8, the control device 60 causes the fuel injection valve 50 and the ignition device 52 to perform start-up combustion processing. That is, the control device 60 supplies fuel to the cylinder 33 by injecting fuel from the fuel injection valve 50 in the intake stroke in which the piston 34 moves toward the bottom dead center according to the crank angle of the crankshaft 40, At the beginning of the combustion stroke when the piston 34 is positioned near the top dead center, the ignition device 52 ignites the fuel in the cylinder 33 . The engine 20 is thereby started.

After that, in step S9, engine control is executed to repeat fuel injection by the fuel injection valve 50 and ignition by the ignition device 52 in accordance with the crank angle.

In this embodiment, when it is determined that the hot start is not performed in step S1 and the cold start is not determined in step S2, it is determined that the predetermined standby condition is not satisfied. In this case, after judging the start of the engine, the starting combustion process is executed without going through the standby process, so the processes after step S21 are executed.

First, in step S21, a simulated standby process completion condition is set. The simulated standby process completion condition is, for example, when the standby condition setting condition 63b is less than or below the first threshold temperature and above or above the second threshold temperature (that is, neither hot start nor low temperature start case), and the control device 60 may set the simulated standby process completion condition by referring to the standby condition setting condition 63b. The simulated standby process completion condition may be set as a condition that is shorter than the period during which the standby process is to be executed. For example, the simulated standby process completion condition may be defined as N rotations of the crankshaft 40, similar to the exhaust operation completion condition. The number of revolutions in this case may be less than the number of revolutions defined as the exhaust operation completion condition. As a result, the number of revolutions N of the crankshaft can be minimized in situations where variations in mixture concentration are relatively unlikely to occur. Therefore, since the crankshaft does not rotate undesirably, it is possible to reduce impairing the feeling of the rider. For example, if the exhaust operation completion condition is defined as two rotations of the crankshaft 40, the simulated standby process completion condition may be defined as one rotation of the crankshaft 40. FIG. The set conditions are temporarily stored in the storage unit.

In the next step S22, it is determined whether or not the start switch 22 has been turned on. The processing of step S22 is repeated until the start switch 22 is turned on, and when the start switch 22 is turned on, the process proceeds to step S23. Note that when the start switch 22 is turned on, a rotation start signal is given to the starter motor 24, and the starter motor 24 rotates.

In steps S23 to S25, the same processes as in steps S4 to S6 are executed.

In step S26 after step S25, it is determined whether or not the simulated standby process completion condition is satisfied. For example, when the simulated standby process completion condition is defined by the rotation speed of the crankshaft 40, the simulated standby process completion condition set in step S21 is compared with the count variable incremented in step S24. It is determined whether or not the standby process completion condition is satisfied. For example, when the simulated standby process completion condition is set as one revolution of the crankshaft 40, when the number of revolutions of the crankshaft 40 becomes one revolution or more (the number of times the protrusion 40Ra of the rotor 40R is detected is two times above), it may be determined that the simulated standby process completion condition is satisfied. If it is determined in step S26 that the simulated standby process completion condition is not satisfied, the process returns to step S23, and the processes of steps S23, S24, and S25 are repeated. If it is determined in step S26 that the simulated standby process completion condition is satisfied, the process proceeds to step S8 to execute the starting combustion process. The processes of steps S23, S24, and S25 are repeated until it is determined in step S26 that the simulated standby process completion condition is satisfied. During this process, the control device 60 keeps the fuel injection by the fuel injection valve 50 stopped. This series of processes is an example of the simulated standby process.

The simulated waiting process may be omitted. In this case, if NO is determined in step S11 (that is, if it is determined that the standby condition is not satisfied), the process may proceed to step S8 to execute the start-up combustion process.

FIG. 4 is a timing chart showing the processing timing of each part of the engine 20 when standby processing is performed.

As shown in FIG. 4, when the power switch 21 is turned on, the control device 60 and the like are energized to enable control operations. After that, when the start switch 22 is turned on, the starter motor 24 rotates, and the rotation of the starter motor 24 causes the crankshaft 40 to rotate.

After that, the rotation of the crankshaft 40 caused by the rotation of the starter motor 24 is detected by the rotation detection device 26 . In this case, the rotation of the crankshaft 40 may be detected with a delay from the rotational drive by the starter motor 24 . For example, if the rotation detection device 26 is a magnetic sensor that detects the rotation of the crankshaft 40 based on changes in the magnetic field, the magnetic field is detected by the rotation detection device 26 when the crankshaft 40 exceeds a certain rotational speed. changes may occur. In such a case, after the starter motor 24 starts rotating the crankshaft 40, the rotation of the crankshaft 40 is detected by the rotation detection device 26 after the rotation speed of the crankshaft 40 reaches a rotation speed exceeding the detection limit. It is possible.

When rotation of the crankshaft 40 is detected, a standby condition control flag in the control device 60 is set, and standby processing (see steps S4 to S7) is executed. During this process, an injection cut command for stopping the fuel injection from the fuel injection valve 50 is output. As a result, fuel injection from the fuel injection valve 50 is stopped during the standby process. When the ignition device 52 is caused to perform the ignition operation during the standby process (see step S6), the ignition cut command during the standby process is not output. When the ignition operation by the ignition device 52 is to be stopped during the standby process, an ignition cut command during the standby process is output (see the two-dot chain line).

Subsequently, the rotation of the crankshaft 40 is detected by the rotation detection device 26, and when it is determined that the rotation speed exceeds the rotation speed specified as the exhaust operation completion condition (for example, 2 rotations, 3 rotations in terms of the number of rotations detected), It is determined that the exhaust operation (standby processing operation) has been completed.

When the exhaust operation (standby processing operation) is completed, the standby condition control flag is cleared and the injection cut command is turned off. It should be noted that if the ignition cut command is output during the exhaust operation, it is similarly turned off. Subsequently, when the start switch 22 is kept on, the starter motor 24 continues to rotate, and the crankshaft 40 continues to rotate due to the starter motor 24 . After the exhaust operation is completed, the starting combustion process is executed, fuel is injected from the fuel injection valve 50, and the ignition device 52 performs an ignition operation. This ignites the fuel in the cylinder 33 and ignites the engine 20 . After the engine is ignited, the ON operation of the start switch 22 is released and the rotation of the starter motor 24 is stopped. By starting the engine 20, the crankshaft 40 continues the idling rotation state.

FIG. 5 is an explanatory diagram showing the operation of the movable parts of the engine 20 when the standby process is performed. FIG. 5 depicts the operation assuming a four-cycle engine.

In (a) of FIG. 5, the piston 34 is moving from the top dead center to the bottom dead center. In this state, the intake valve 47 is opened and the exhaust valve 48 is closed. Therefore, outside air can flow into the cylinder 33 through the intake port. In FIG. 5(b), the piston 34 is moving from the bottom dead center to the top dead center. In this state, both the intake valve 47 and the exhaust valve 48 are closed and the gas in the cylinder 33 is compressed. In (c) of FIG. 5, the piston 34 is positioned near the top dead center. In this state, both the intake valve 47 and the exhaust valve 48 are closed, and the gas in the cylinder 33 is in the most compressed state. In (d) of FIG. 5, the piston 34 is moving from the bottom dead center to the top dead center. In this state, the intake valve 47 is closed and the exhaust valve 48 is opened. Therefore, the gas in the cylinder 33 is discharged to the outside through the exhaust port.

In the starting combustion process and the normal operation control process of the engine 20 (see steps S8 and S9), fuel is injected from the fuel injection valve 50 in the process shown in FIG. 5(a) (intake stroke). In the next process shown in FIG. 5(b), the air-fuel mixture containing the fuel is compressed in the cylinder 33 (compression process). 5C, the fuel contained in the air-fuel mixture in the cylinder 33 is ignited by the ignition device 52, causing the gas in the cylinder 33 to expand and the piston 34 to move toward the bottom dead center. Pushed (ignition/expansion process). By the process shown in FIG. 5D after this, the gas after combustion in the cylinder 33 is discharged by the piston 34 . In this way, the stroke of reciprocating the piston 34 twice (rotating the crankshaft 40 twice) is repeated in the above order as one cycle.

In the exhaust operation executed by the standby process, the rotation of the crankshaft 40 causes the piston 34 to reciprocate, and the intake valve 47 and the exhaust valve 48 of the valve mechanism 46 operate in conjunction with the rotation of the crankshaft 40 . Unlike the above, fuel injection from the fuel injection valve 50 is stopped in the process shown in FIG. 5(a). For this reason, an intake operation accompanied by introduction of fresh outside air into the cylinder 33 is performed.

Note that the control device 60 may control the air supply amount adjusting device 47V during the standby process so that the intake passage area of the intake port 47P is made larger than before the standby process. For example, the intake passage area of the intake port 47P is adjusted by the opening of the throttle valve 47Va of the air supply amount adjusting device 47V. When the throttle valve 47Va is in a state in which the intake port 47P is closed most before the standby process, the throttle valve 47Va is opened in the standby process so that outside air flows through the intake port 47P. You can make it easier. The degree of opening of the throttle valve 47Va during the standby process may be the same as the degree of opening during idling, or may be between the degree of opening during idling and fully open. The intake air amount from the intake port 47P in the standby process may be adjusted by an idle speed control valve. The idle speed control valve is a valve that adjusts the flow rate in the bypass passage of the intake port 47P, and can be understood as a constituent part of the intake air amount adjusting device. It should be noted that the area of the intake passage should be increased at least during the intake stroke (see FIG. 5(a)).

The gas in the cylinder 33 is compressed in the next step shown in FIG. 5(b), and the piston 34 reaches near the top dead center in the next step shown in FIG. 5(c). In the process shown in FIG. 5(c), when the ignition device 52 performs the ignition operation, as described above, fresh outside air is taken into the cylinder 33, so ignition is difficult. However, if fuel remains in cylinder 33, the remaining fuel may be ignited. This ignition may ignite the engine 20, followed by normal operating control of the engine.

In the stroke shown in FIG. 5(d), the rotation of the crankshaft 40 moves the piston 34 toward the top dead center. As a result, the exhaust operation is executed, and even if unburned gas remains in the cylinder 33, the residual unburned gas is discharged to the outside through the exhaust port.

When the standby process is executed during the period including the intake operation (see FIG. 5(a)) and the exhaust operation (see FIG. 5(d)), the residual fuel in the cylinder 33 is easily discharged. Assuming a 4-cycle engine, if the crankshaft 40 rotates twice, all the cycles (a), (b), (c), and (d) are performed regardless of the number of cylinders and the positions of the cylinders. Introduction of fresh outside air to and exhaust of gas in cylinder 33 is performed. Therefore, the condition for determining that the exhaust process has been completed may be set so that the crankshaft 40 has made two or more predetermined rotations. In this way, by determining the completion of the exhaust operation based on the number of rotations of the crankshaft 40, the completion timing of the exhaust operation can be accurately determined as compared with the case where the completion of the exhaust operation is determined based on the elapsed time or the like. I can judge.

According to the engine 20, the control device 60, and the method for the engine 20 configured in this way, the fuel injection is stopped during the standby process (exhaust operation) after starting. Therefore, in the standby process, the unburned gas remaining in the cylinder 33 is discharged by the exhaust operation of the valve mechanism 46 (the operation of opening the exhaust valve 48 ) interlocked with the reciprocation of the piston 34 . In the subsequent start-up combustion process, fuel is supplied to the cylinder 33 after the unburned gas remaining in the cylinder 33 is temporarily discharged. Therefore, by suppressing the influence of the residual unburned gas, it is possible to suppress variations in the air-fuel mixture concentration in the cylinders 33 when the engine 20 is started. In addition, it is possible to prevent poor combustion due to the influence of residual unburned gas, thereby preventing deterioration in startability.

Further, if the standby condition, which is the criterion for determining whether or not to perform the standby process, is set based on the temperature of the engine 20 before combustion, the air-fuel mixture concentration caused by residual unburned gas in the cylinder 33 Standby conditions are set according to the temperature that affects the temperature, and appropriate exhaust of residual unburned gas is attempted.

That is, if residual unburned gas due to blow-by gas or the like remains in the cylinder 33 before combustion, even if an attempt is made to supply more fuel to the cylinder 33 for ignition, the air-fuel mixture concentration becomes excessively rich. It may not be possible to ignite. When the engine 20 is hot-started, the fuel in the cylinders 33 tends to volatilize, so the mixture concentration in the cylinders 33 tends to be affected. Therefore, whether or not to perform the standby process is determined based on the temperature of the engine 20 before combustion, and in particular, when it is determined that the hot start is performed, the standby process is performed. As a result, the engine 20 can be smoothly started by eliminating the influence of the residual unburned gas, which is susceptible to the effects of the hot start.

Further, if ignition fails during low-temperature starting, excessive fuel may remain in the cylinder 33, causing so-called plug fogging. Therefore, whether or not to perform the standby process is determined based on the temperature of the engine 20 before combustion, and in particular, when it is determined that the engine is started at a low temperature, the standby process is performed. As a result, when the engine is started at a low temperature, the excessively supplied fuel is temporarily discharged, and the engine 20 can be started smoothly.

The standby process may be performed only when it is determined to be a hot start or when it is determined to be a low temperature start. The period for which the standby process is performed (the number of rotations of the crankshaft 40, the elapsed time, etc.) may be different between when it is determined to be a hot start and when it is determined to be a low temperature start. Also, in hot start or low temperature start, the period for performing the standby process (which can be defined by the number of revolutions of the crankshaft 40, the elapsed time, etc.) may be varied according to the temperature of the engine 20 before combustion. For example, the temperature higher than the room temperature may be divided into three stages, and the periods may be varied according to each stage so that the higher the temperature, the longer the period during which the standby process is performed.

Further, the control device 60 causes the ignition device 52 to perform an ignition operation when executing the standby process. If ignition occurs during the standby process, there is a possibility that the engine 20 will start quickly.

If the standby condition is not satisfied, the control device 60 may determine the start of engine start and then execute the engine start combustion process without performing the standby process. As a result, the engine 20 can be quickly started in a state in which no waiting is required.

If the standby condition is not satisfied, the control device 60 executes a simulated standby process for maintaining the state in which the fuel injection is stopped for a period shorter than the standby process, and after the simulated standby process is completed, even if the starting combustion process is executed. good. In this case, even if the standby condition is not satisfied, the starting combustion process is executed after the simulated standby process is executed. Therefore, it is possible to suppress variations in the time required to start the engine 20 depending on whether or not the standby process is performed.

Further, the control device 60 executes the standby process at least during the intake operation (see FIG. 5(a)) and the exhaust operation (see FIG. 5(d)). Therefore, fresh outside air is introduced into the cylinders 33 and the gas in the cylinders 33 is discharged, so that the unburned gas remaining in the cylinders 33 is further reduced.

Further, when executing the standby process, the control device 60 controls the air supply amount adjusting device 47V so as to increase the intake passage area compared to before the standby process. Therefore, the amount of intake air introduced to the cylinder 33 can be increased. By introducing a large amount of fresh outside air, the amount of unburned gas remaining in the cylinders 33 can be further reduced.

Since the control device 60 determines the timing at which the exhaust operation is completed based on the detection result of the rotation detection device 26 that detects the rotation of the crankshaft 40, the timing at which the exhaust operation is completed can be accurately estimated. is suppressed until the end of the fuel injection.

In the above embodiment, after the crankshaft 40 starts rotating, whether or not the exhaust operation is completed is determined based on the number of rotations of the crankshaft 40. However, whether or not the exhaust operation is completed is determined based on other criteria. good too. For example, the time after the rotation of the crankshaft 40 is detected may be compared with a predetermined reference elapsed time, and if the reference elapsed time is exceeded, it may be determined that the exhaust operation has been completed. The reference elapsed time is preferably set to a time that is assumed to be appropriate for the exhaust operation to be performed after the crankshaft 40 starts rotating.

Determination of the predetermined standby condition may be determined based on a condition other than the temperature of the engine 20 . For example, the elapsed time from the previous engine stop is compared with a predetermined threshold elapsed time, and if the elapsed time has not passed the predetermined threshold elapsed time, it is determined that the standby condition is met. good too. Further, a condition under which it is assumed that fuel remains in the intake port 47P and the cylinder 33 from various states of the engine 20 may be set as the standby condition. For example, the standby condition may be set by combining the temperature of each part of the engine 20, the elapsed time since the previous engine stop, and the like. The standby conditions are empirically, experimentally, and inferentially set in view of the volume per cylinder 33, the displacement, the number of cylinders, the fuel injection capability of the fuel injection valve 50, the fuel injection capability with respect to the volume of the cylinder 33, and the like. may

The predetermined standby condition may be set as a condition that can be satisfied under all conditions regardless of the temperature of engine 20 . In this case, if the start switch 22 is turned on regardless of the temperature of the engine 20, standby processing (exhaust processing) is executed in all cases. In this case, it is easy to align the timing of starting the engine 20 after the start switch 22 is turned on.

It should be noted that the configurations described in the above embodiment and modifications can be appropriately combined as long as they do not contradict each other.

The specification and drawings disclose each of the following aspects.

A first aspect includes a cylinder, a piston that reciprocates in the cylinder, a crankshaft that rotates in conjunction with the reciprocation of the piston, and an intake operation into the cylinder in conjunction with the reciprocation of the piston. and a valve mechanism that performs an exhaust operation, a fuel injection valve that injects fuel, an ignition device that ignites the fuel in the cylinder, and a control device that controls the fuel injection valve and the ignition device. When a predetermined standby condition is satisfied, a standby process is executed to maintain a state in which the fuel injection is stopped from when it is determined that the engine has started to start until it is determined that the exhaust operation by the valve mechanism has been performed, and and a control device for executing a starting combustion process for controlling the fuel injection valve to inject fuel and controlling the ignition device to ignite the fuel in a cylinder when the standby process ends.

According to this engine, the fuel injection is stopped during the execution of the standby process after starting the engine. As a result, in the standby process, the unburned gas remaining in the cylinder is discharged by the exhaust operation of the valve mechanism caused by the reciprocation of the piston. In a state in which the subsequent starting combustion process is executed, fuel combustion is executed in a state in which residual unburned gas in the cylinder is exhausted. By discharging the remaining unburned gas before starting in this manner, the influence of the remaining unburned gas can be suppressed, and variations in the concentration of the air-fuel mixture in the combustion chamber when the engine is started can be suppressed. As a result, for example, poor combustion due to the influence of residual unburned gas can be prevented, and deterioration in startability can be prevented.

A second aspect is the engine according to the first aspect, wherein the standby condition is set based on the temperature of the engine before combustion. In this case, the standby condition is set according to the temperature that affects the mixture concentration due to the residual fuel in the cylinder, and the residual fuel is properly discharged.

A third aspect is the engine according to the first or second aspect, wherein the control device performs an ignition operation when executing the standby process. In this case, there is a possibility that the engine can be started quickly by permitting ignition in the standby state.

A fourth aspect is the engine according to any one of the first to third aspects, wherein when the standby condition is not satisfied, the control device judges the start of the start and then goes through the standby process. The starting combustion process is executed without In this case, it is possible to quickly start the engine without waiting.

A fifth aspect is the engine according to any one of the first to fourth aspects, wherein when the standby condition is not satisfied, the control device judges the start of the start, and then the standby process is performed. A simulated standby process for maintaining a state in which the fuel injection is stopped is executed for a period shorter than the period during which the fuel injection is executed, and when the simulated standby process is completed, the starting combustion process is executed. As a result, it is possible to suppress variations in the time required for starting depending on the presence or absence of standby processing.

A sixth aspect is the engine according to any one of the first to fifth aspects, wherein the control device executes the standby process at least during a period in which the intake operation and the exhaust operation are performed. is. In this case, the intake operation is performed in the standby process, thereby further reducing the amount of unburned gas remaining in the cylinder.

A seventh aspect is the engine according to any one of the first to sixth aspects, further comprising an intake air amount adjusting device that adjusts an intake air amount into the cylinder, wherein the control device performs the standby process is executed, the intake passage area is increased compared to before the standby process. As a result, the amount of intake air introduced into the cylinder can be increased, and the amount of unburned gas remaining in the cylinder can be further reduced.

An eighth aspect is the engine according to any one of the first to seventh aspects, further comprising a rotation detection device for detecting rotation of the crankshaft, wherein the control device detects rotation of the rotation detection device. Based on the results, the timing at which the exhaust operation ends is determined. In this case, the control device can accurately estimate the timing at which the intake operation ends, and can suppress fuel injection before the exhaust ends.

A ninth aspect is an engine control device for controlling a fuel injection valve and an ignition device in an engine, comprising: (a) when a predetermined standby condition is satisfied, it is determined that a start-up should be started, and then an exhaust operation is performed by a valve mechanism; (b) when the standby process is completed, the fuel injection valve is controlled to inject fuel, and the ignition device is controlled. and a starting combustion process for igniting the fuel in the cylinder.

According to this engine control device, the fuel injection is stopped during the execution of the standby process after starting the engine. As a result, in the standby process, the unburned gas remaining in the cylinder is discharged by the exhaust operation of the valve mechanism caused by the reciprocation of the piston. In a state in which the subsequent starting combustion process is executed, fuel combustion is executed in a state in which residual unburned gas in the cylinder is exhausted. By discharging the remaining unburned gas before starting in this manner, the influence of the remaining unburned gas can be suppressed, and variations in the concentration of the air-fuel mixture in the combustion chamber when the engine is started can be suppressed. As a result, for example, poor combustion due to the influence of residual unburned gas can be prevented, and deterioration in startability can be prevented.

A tenth aspect is an engine control method for controlling a fuel injection valve and an ignition device in an engine, comprising: (a) when a predetermined standby condition is satisfied, it is determined that a start is to be started, and then an exhaust operation is performed by a valve mechanism; (b) when the process (a) is completed, the fuel injection valve is controlled to inject fuel, and the ignition device is controlled. and igniting the fuel in the cylinder.

According to this engine control method, the fuel injection is stopped during the execution of the standby process after starting the engine. As a result, in the standby process, the unburned gas remaining in the cylinder is discharged by the exhaust operation of the valve mechanism caused by the reciprocation of the piston. In a state in which the subsequent starting combustion process is executed, fuel combustion is executed in a state in which residual unburned gas in the cylinder is exhausted. By discharging the remaining unburned gas before starting in this manner, the influence of the remaining unburned gas can be suppressed, and variations in the concentration of the air-fuel mixture in the combustion chamber when the engine is started can be suppressed. As a result, for example, poor combustion due to the influence of residual unburned gas can be prevented, and deterioration in startability can be prevented.

The above description is illustrative in all aspects, and the present invention is not limited thereto. It is understood that numerous variations not illustrated can be envisioned without departing from the scope of the invention.

20 Engine 26 Rotation detection device 27 Water temperature sensor 28 Oil temperature sensor 33 Cylinder 34 Piston 40 Crankshaft 46 Valve mechanism 47 Intake valve 47V Air supply amount adjustment device 48 Exhaust valve 50 Fuel injection valve 52 Ignition device 60 Control device

Claims (10)

A cylinder, a piston that reciprocates within the cylinder, a crankshaft that rotates in conjunction with the reciprocation of the piston, and a movement that performs intake and exhaust operations into the cylinder in conjunction with the reciprocation of the piston. an engine body having a valve mechanism;
a fuel injection valve that injects fuel;
an ignition device that ignites the fuel in the cylinder;
A control device for controlling the fuel injection valve and the ignition device, wherein when a predetermined standby condition is satisfied, fuel injection is continued until it is determined that the exhaust operation by the valve mechanism has been performed after determining that the start-up is started. A standby process for maintaining the stopped state is executed, and when the standby process is completed, a starting combustion process is performed for controlling the fuel injection valve to inject fuel and controlling the ignition device to ignite the fuel in the cylinder. a controller that executes
engine with The engine of claim 1, comprising:
The engine, wherein the standby condition is set based on a temperature associated with the engine before combustion. An engine according to claim 1 or claim 2,
The engine, wherein the control device performs an ignition operation when executing the standby process. An engine according to any one of claims 1 to 3,
The engine, wherein when the standby condition is not satisfied, the control device executes the start combustion process without performing the standby process after judging the start of the engine. An engine according to any one of claims 1 to 4,
The control device is
If the standby condition is not satisfied, executing a simulated standby process for maintaining a state in which fuel injection is stopped for a period shorter than the period during which the standby process is executed after determining the start of the engine,
The engine that executes the starting combustion process when the simulated standby process ends. An engine according to any one of claims 1 to 5,
The engine, wherein the control device executes the standby process at least during a period in which the intake operation and the exhaust operation are performed. An engine according to any one of claims 1 to 6,
further comprising an intake air amount adjusting device that adjusts the amount of intake air into the cylinder;
The engine, wherein when executing the standby process, the control device increases an intake passage area compared to before the standby process. An engine according to any one of claims 1 to 7,
further comprising a rotation detection device that detects rotation of the crankshaft;
The engine, wherein the control device determines the timing at which the exhaust operation ends based on the detection result of the rotation detection device. An engine control device for controlling a fuel injection valve and an ignition device in an engine,
(a) when a predetermined standby condition is satisfied, a standby process for maintaining a state in which fuel injection is stopped from when it is determined that the engine has started to start until it is determined that the exhaust operation by the valve mechanism has been performed;
(b) starting combustion processing for controlling the fuel injection valve to inject fuel and controlling the ignition device to ignite the fuel in the cylinder when the standby processing ends;
The control unit of the engine that executes An engine control method for controlling a fuel injection valve and an ignition device in an engine,
(a) when a predetermined standby condition is satisfied, a process of maintaining a state in which fuel injection is stopped from when it is determined that the engine has started to start until it is determined that the exhaust operation by the valve mechanism has been performed;
(b) when the process (a) ends, a process of controlling the fuel injection valve to inject fuel and controlling the ignition device to ignite the fuel in the cylinder;
A method of controlling an engine, comprising:

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