JP4367646B2 - Engine starter - Google Patents

Description

  The present invention relates to an engine starter, and more particularly to a starter that starts an engine with a combustion pressure generated by fuel injection and ignition in a cylinder.

Conventionally, it has been common to use a starter motor when starting an engine. However, in recent years, in order to reduce the noise at the time of starting the engine and realize a quick start, the cranking by the starter motor is not performed. There has been proposed a starting device in which fuel is injected and ignited in a cylinder of an engine to start the engine.
In this starting device, when the engine is stopped, the cylinder in the expansion stroke is determined, and when the engine is started in accordance with the start operation of the driver, etc., the fuel is injected after the fuel is injected into the expansion stroke cylinder. The injected fuel is burned, and the engine is started by the combustion pressure generated at this time.

  However, there is a problem that sufficient combustion pressure cannot be obtained only by fuel supply and ignition to the cylinder that was in the expansion stroke when the engine was stopped, or that the rotational fluctuation at the time of starting the engine becomes too large. In particular, when the piston of the expansion stroke cylinder is at a position where the crank angle from the top dead center is 90 ° or more, the fuel injected by the expansion of the cylinder volume is sufficiently large in the cylinder. Since it cannot be mixed with air and the combustion pressure required for starting cannot be ensured, and the exhaust valve is also starting to open, the combustion pressure can easily escape and the engine can be difficult to start.

Therefore, in order to solve such a problem, there has been proposed a starting device that secures a torque necessary for starting the engine by injecting fuel and igniting the cylinder that was in the intake stroke when the engine was stopped. (For example, patent document 1).
JP 2004-346770 A

However, for the cylinders that were in the intake stroke when the engine was stopped, the intake valve was in an open state, so the combustion pressure easily escaped, and the problem was that explosive wind blows back to the upstream side of the intake system through the intake port. Arise.
In the starting device of Patent Document 1 described above, the intake valve is forcibly closed in order to avoid such a problem, but in order to forcibly close the intake valve in this way, the valve system of the engine is used. It is necessary to provide a variable mechanism for changing the valve opening / closing timing and valve lift individually for all cylinders, and immediately after starting the engine, the valve opening / closing timing and valve lift must be adjusted to suit normal engine operation. Therefore, there is a problem that the structure of the valve operating mechanism and the control of the engine become extremely complicated.

The present invention has been made in view of such problems, and the object of the present invention is to secure a starting force necessary for starting the engine by combustion of fuel in the cylinder regardless of the piston position when the engine is stopped. Another object of the present invention is to provide an engine starter that can start the engine reliably and quickly.

In order to achieve the above object, an engine starter according to the present invention is an engine starter in which at least one of the plurality of cylinders is in an expansion stroke and at least one of the remaining cylinders is in an intake stroke. A fuel injection valve provided in each of the plurality of cylinders for injecting fuel into the cylinder; a spark plug provided in each of the plurality of cylinders for igniting the fuel injected into the cylinder; and Cylinder discrimination means provided in the intake passage and driven by an electric motor to supercharge intake air of the engine, and cylinder discrimination means for discriminating between a cylinder in an expansion stroke and a cylinder in an intake stroke when the engine is stopped If, depending on the electric supercharger and piston position detecting means for detecting the position of each piston of said plurality of cylinders, a cylinder that was in an intake stroke during engine stoppage In addition to supplying supercharged intake air, fuel is supplied from the fuel injection valve to the cylinder that was in the expansion stroke and the cylinder that was in the intake stroke when the engine was stopped, and the supplied fuel was ignited by the spark plug. And a control means for starting the engine .

  According to the engine starter configured as described above, when starting the engine, the intake air supercharged by the electric supercharger is supplied to the cylinder that was in the intake stroke when the engine was stopped. Then, fuel is supplied to the cylinder that was in the expansion stroke and the cylinder that was in the intake stroke when the engine was stopped, and ignition is performed. Then, the engine is started by the combustion pressure of at least two cylinders generated thereby.

In the engine starter of the present invention, the control means is a position where the piston position of the cylinder that was in the expansion stroke when the engine was stopped corresponds to a crank angle less than a predetermined crank angle after top dead center. sometimes it characterized by starting the engine by igniting by supplying fuel only to the cylinder that was in an expansion stroke during the engine stop.

According to the engine starter configured as described above, when the piston position of the cylinder that was in the expansion stroke when the engine was stopped is a position corresponding to a crank angle less than a predetermined crank angle after top dead center. When the engine is stopped, the engine is started with the combustion pressure generated by supplying fuel to only the cylinders that were in the expansion stroke and igniting them.
Preferably, the apparatus further includes a starter motor capable of cranking the engine and a temperature detection means for detecting the temperature of the engine, and the control means is configured such that the engine temperature detected by the temperature detection means is equal to or lower than a predetermined temperature. sometimes, characterized by starting the engine with the starter motor (claim 2).

According to the engine starter configured as described above, when the engine temperature is equal to or lower than the predetermined temperature, the engine is started using the starter motor.
Preferably, the apparatus further comprises a starter motor capable of cranking the engine and a rotation speed detection means for detecting the rotation speed of the engine, wherein the control means is configured to supply fuel into the cylinder and ignite the fuel. The engine is started using the starter motor when the rotation speed of the engine detected by the rotation speed detection means does not increase above a predetermined value after the engine is started. 3 ).

  According to the engine starter configured as described above, when the engine speed does not increase beyond a predetermined value after the engine is started by fuel supply and ignition in the cylinder, the starter motor is used to start the engine. Start is performed.

  According to the engine starter of the present invention, since the engine is started by the combustion pressures of the cylinders that are in the expansion stroke and the cylinders that are in the intake stroke when the engine is stopped, the engine is expanded when the engine is stopped. It is possible to obtain a larger starting force than when the engine is started with the combustion pressure of only the cylinder in the stroke, and even if the piston is located at a position where the volume in the cylinder is relatively large, the engine is reliably started. This makes it possible to start the engine more quickly.

In addition, when starting the engine, the intake air supercharged by the electric supercharger is supplied to the cylinder that was in the intake stroke when the engine was stopped. Even when the piston is located at a position where the temperature rises and fuel vaporization is promoted and the volume in the cylinder becomes relatively large, the air-fuel mixture in the cylinder can be burned well.
Further, the supply of supercharged intake air makes it difficult for the pressure in the cylinder to escape even when the intake valve is open, so that the generated combustion pressure can be effectively utilized for engine startup.

According to the engine starter of the present invention , when the piston position of the cylinder that was in the expansion stroke when the engine was stopped is a position corresponding to a crank angle less than a predetermined crank angle after top dead center, Fuel is supplied and ignited only to the cylinder that was in the expansion stroke when the engine was stopped, but when the piston is in such a position, the volume in the cylinder is relatively small, and the fuel and air The mixture was sufficiently mixed and good combustion could be obtained, so even if the combustion pressure of the cylinder that was in the intake stroke when the engine was stopped was not used, it was in the expansion stroke when the engine was stopped It is possible to secure the combustion pressure necessary for starting the engine only by supplying fuel to the cylinder and igniting.

Therefore, in such a case, it is not necessary to supply fuel to the cylinder that was in the intake stroke when the engine was stopped, so that fuel consumption can be improved.
Further, when the engine temperature is low is not performed vaporization of fuel in the cylinder is sufficient, there is a case where the combustion pressure required to start the engine can not be obtained, according to the starting system of claim 2 engine, engine Since the starter motor is used to start the engine when the temperature is equal to or lower than the predetermined temperature, the engine can be reliably started even when the engine temperature is low.

If the fuel supply into the cylinder and the start by ignition are also used at this time, the amount of power consumed by the starter motor can be reduced, and the fuel supply into the cylinder and the start by ignition are performed. If not, the fuel consumption and the power consumption in the electric supercharger can be reduced.
Further, according to the engine starting system according to claim 3, when the rotational speed of the engine does not rise above a predetermined value after the starting of the engine by the ignition and fuel supply to the cylinder, the engine using the starter motor Since the engine is started, the engine can be reliably started even when the engine cannot be started by supplying fuel and igniting the cylinder for some reason.

Hereinafter, an embodiment in which the present invention is embodied in an engine starter mounted on an idle stop vehicle will be described with reference to the drawings.
As shown in the overall configuration diagram of FIG. 1, the engine 1 of the present embodiment is configured as an in-cylinder injection type in-line four-cylinder engine, and a fuel injection valve 2 and a spark plug 4 are provided in each cylinder. The fuel injection valve 2 of each cylinder is configured to be able to directly inject fuel into the cylinder, that is, into the combustion chamber 6, and fuel is supplied to each fuel injection valve 2 from a fuel pump (not shown) at a predetermined pressure.

Intake is introduced into the combustion chamber 6 of each cylinder through the intake port 10 as the intake valve 8 is opened, and fuel is injected from the fuel injection valve 2 at a predetermined timing during the introduced intake air. The injected fuel is ignited by the ignition plug 4 in the vicinity of the compression top dead center, and the combustion pressure is applied to the piston 12 to rotationally drive a crankshaft (not shown).
On the other hand, the exhaust gas after combustion is discharged to the outside from the exhaust port 16 through a catalyst and a silencer (not shown) when the exhaust valve 14 is opened.

  The intake port 10 is branched from the surge tank 18 for each cylinder, and an intake passage 24 including an electronic throttle valve 22 that is opened and closed by an electric actuator 20 is connected to the upstream side of the surge tank 18. In addition, an electric supercharger 26 is interposed upstream of the electronic throttle valve 22, and the electric supercharger 26 is driven by an electric motor 28 to supercharge intake air to the engine 1. In the state where the electric supercharger 26 is not driven by the electric motor 28, intake air that is not supercharged is supplied to the engine 1. The electric supercharger 26 may be used in combination with driving by a turbine using exhaust from the engine 1 in addition to driving by the electric motor 28.

The engine 1 includes a starter motor 30 for cranking the engine 1 in the same way as a general engine. The pinion gear 32 of the starter motor 30 is meshed with a ring gear 34 of a crankshaft (not shown) and is driven to rotate. By doing so, the engine 1 is cranked.
Further, the engine 1 includes a water temperature sensor (temperature detection means) 36 that detects the cooling water temperature of the engine 1 as the engine temperature, a crank angle sensor 38 that outputs a crank angle signal in synchronization with the rotation of the crankshaft of the engine, A cam angle sensor 40 that outputs a TOP signal in synchronization with the rotation is provided.

The ECU (control means) 42 is a control device for performing comprehensive control including operation control of the engine 1 for operating the engine such as fuel injection control and ignition timing control, and includes a CPU, a memory, a timer counter, and the like. Are configured to calculate various control amounts and control various devices based on the control amounts.
On the input side of the ECU 42, in addition to the water temperature sensor 36, the crank angle sensor 38, and the cam angle sensor 40 described above, a vehicle speed sensor 44 that detects the traveling speed of the vehicle, a driver, Various sensors such as a brake switch 46 for detecting a brake operation by a shift lever and a shift position sensor 48 for detecting an operation position of a select lever provided in a driver's seat and an ignition switch 50 are connected, and an operation is performed on the output side. Various devices such as the fuel injection valve 2, the spark plug 4, the electric actuator 20 of the electronic throttle valve 22, the electric motor 28 of the electric supercharger 26, and the starter motor 30 of each cylinder to be controlled based on the control amount are connected. ing.

The engine 1 thus configured is connected to an automatic transmission (not shown) and mounted on the vehicle, and the output of the engine 1 is transmitted to the drive wheels of the vehicle via the automatic transmission to drive the vehicle.
On the other hand, the ECU 42 executes idle stop control for temporarily automatically stopping the engine 1 while the vehicle is stopped due to a signal waiting or traffic jam. In this embodiment, as engine stop conditions, the vehicle speed V detected by the vehicle speed sensor 44 is 0 km / h, the brake operation is detected by the brake switch 46, and the shift position detected by the shift position sensor 48. Is set to be a travel range such as a D (drive) range or an N (neutral) range, and when these conditions are satisfied, the ECU 42 stops the fuel injection control and the ignition timing control and stops the engine. .

  Further, as engine start conditions in the idle stop control, the release of the brake operation is detected by the brake switch 46, and the shift position detected by the shift position sensor 48 is a travel range such as the D range. If these conditions are satisfied, the ECU 42 restarts the fuel injection control and the ignition timing control and starts the engine 1.

At the time of engine start in the idling stop control described above or at the time of normal engine start based on the start operation of the ignition switch 50 by the driver, the ECU 42 performs fuel injection and ignition in the cylinder for the purpose of quick and low noise start. The start-only control for starting the engine 1 with the combustion pressure generated by the above is executed, and the details of the start control will be described below.
2 and 3 show a flowchart of the start control, and the ECU 42 executes a start control routine based on this flowchart at a predetermined control period during use of the vehicle. This start control routine is always executed except when the ignition switch 50 is in the OFF position, and it is considered to continue even when the engine 1 is stopped and started by the driver's key operation (that is, once switched to the accessory position). ing.

When the start control routine is started, first, in step S2, it is determined whether or not the engine speed Ne obtained based on the detection signal of the crank angle sensor 38 is less than a stop determination value Ner (for example, 30 rpm). When it is determined that the engine rotation speed Ne is equal to or higher than the stop determination value Ner, it is considered that the engine 1 is in operation and the process proceeds to step S4.
In step S4, it is determined whether an engine stop command has been input. This engine stop command is input when the engine stop condition is established in the idle stop control or when the ignition switch 50 is turned OFF by the driver. If the engine stop command is not input, the current control is performed. The start control routine in the cycle is terminated, and the processing is performed again from step S2 in the next control cycle.

On the other hand, if an engine stop command is input, the process proceeds from step S4 to step S6, the fuel injection control and the ignition timing control are stopped, the engine 1 is stopped, and the process proceeds to step S8.
In step S8, based on the crank angle signal detected by the crank angle sensor 38 and the TOP signal detected by the cam angle sensor 40, a cylinder in the expansion stroke (hereinafter referred to as an expansion stroke cylinder) immediately before the engine is stopped. And the cylinders in the intake stroke (hereinafter referred to as intake stroke cylinders), and in the next step S10, the piston positions of the expansion stroke cylinder and the intake stroke cylinder are detected by the crank angle sensor 38. The crank angle after the top dead center is detected based on the angle signal, and after the determination result and the detection result are stored in the storage device, the start control routine in the current control cycle is terminated.

Therefore, in the present embodiment, the ECU 42 corresponds to the cylinder discrimination means, and the crank angle sensor 38 corresponds to the piston position detection means.
When the engine 1 is stopped in this way and the engine rotational speed Ne falls below the stop determination value Ner, the process proceeds from step S2 to step S12.
In step S12, it is determined whether an engine start command has been input. This engine stop command is input when the engine 1 is in a stopped state and the engine start condition is satisfied in the idle stop control or when the ignition switch 50 is started by the driver. When there is no input, the start control routine in the current control cycle is terminated, and in the next control cycle, the routine proceeds again from step S2 to step S12, and the presence or absence of an engine start command is determined.

When an engine start command is input and the process proceeds from step S12 to step S14, it is determined whether or not the coolant temperature Tw of the engine 1 detected by the temperature sensor 36 is equal to or lower than a predetermined determination temperature Tws. It is determined whether or not the engine temperature is such that the fuel injected into the fuel can be sufficiently vaporized.
If it is determined in step S14 that the coolant temperature Tw is equal to or lower than the determination temperature Tws, the fuel in the cylinder is insufficiently vaporized, so that a sufficient explosive force cannot be obtained and is necessary for starting the engine 1. In step S34, the engine 1 is cranked by operating the starter motor 30 for a predetermined time, and the engine 1 is started.

On the other hand, if it is determined in step S14 that the coolant temperature Tw is higher than the determination temperature Tws, it is determined that the engine 1 can be started by fuel injection into the cylinder and ignition, and the process proceeds to step S16.
In step S16, the crank angle after top dead center indicating the position of the piston 12 of the expansion stroke cylinder detected and stored in step S10 when the engine 1 is stopped is read, and is this crank angle equal to or greater than a predetermined crank angle? Determine whether or not. When the piston 12 is located at a position where the crank angle is larger than this predetermined crank angle, the volume in the cylinder is too large so that the fuel and air in the fuel cylinder cannot be sufficiently mixed, and the expansion stroke cylinder This is equivalent to the piston position where starting of the engine 1 may be difficult with only the combustion pressure of the engine.

  If it is determined in step S16 that the crank angle after the top dead center corresponding to the piston position of the expansion stroke cylinder is equal to or greater than the predetermined crank angle, the process proceeds to step S18, and the electric supercharger 26 is driven by the electric motor 28. Is activated. The intake air supercharged by the operation of the electric supercharger 26 passes through the intake passage 24, passes through the electronically controlled throttle valve 22 at the idle opening degree, and reaches the intake port 10. At this time, since the intake valve of the intake stroke cylinder is opened, the supercharged intake air flows into the intake stroke cylinder.

  Next, in step S20, fuel is injected from the fuel injection valve 2 into the expansion stroke cylinder and the intake stroke cylinder. The fuel injection at this time is executed based on the information stored in step S8 and step S10, and the fuel injection amount based on the in-cylinder air amount calculated from the respective piston positions of the expansion stroke cylinder and the intake stroke cylinder. And the fuel is injected into the expansion stroke cylinder and the intake stroke cylinder based on the calculated fuel injection amount.

At this time, intake air whose temperature has increased due to supercharging flows into the intake stroke cylinder, and vaporization of the injected fuel and mixing with the intake air are promoted, so that the cylinder volume is relatively large. However, fuel and air can be sufficiently mixed in a short time.
In the next step S22, after a predetermined time has elapsed since the fuel injection in step S20, the spark plug 4 ignites the fuel in the expansion stroke cylinder and the intake stroke cylinder. Then, the piston 12 of each cylinder is pushed down by the combustion pressure generated by the ignition of the fuel, and the engine 1 is started. At this time, although the intake valve 8 of the intake stroke cylinder is in the open state, the supply of intake air whose pressure has been increased from the electric supercharger 26 is directed toward the intake passage 24 of the explosion air generated in the intake stroke cylinder. Can be suppressed. Further, since the electronic throttle valve 22 is also held at the idle opening, the blowback is also suppressed by the electronic throttle valve 22.

  At this time, in the expansion stroke cylinder, when the piston position is relatively close to the bottom dead center, the exhaust valve 14 starts to open, so that the combustion pressure decreases by escaping through the exhaust valve 14 where the combustion pressure is opened. Although there is a possibility, the engine 1 is started with the combustion pressures of the two cylinders of the expansion stroke cylinder and the intake stroke cylinder by generating the combustion pressure by injecting and igniting the fuel in the intake stroke cylinder as described above. Therefore, the starting force necessary for starting the engine 1 can be ensured regardless of the stop position of the Pilton.

  When the engine is started in this way and the process proceeds to the next step S24, the engine rotational speed Ne detected based on the detection signal of the crank angle sensor 38 after a predetermined time has elapsed since ignition was performed in step S22 is determined as a start determination. It is determined whether or not the value is equal to or greater than Nes. The start determination value Nes is a threshold value for determining that the injected fuel in the cylinder is normally burned and the operation of the engine 1 is started. In step S32, the engine speed Ne is equal to or greater than the start determination value Nes. If it is determined that there is an engine, it is assumed that the engine 1 has been started normally, and after proceeding to step S26 to stop the electric supercharger 26, the start control routine in the current control cycle is terminated.

  As described above, when the crank angle after the top dead center indicating the piston position of the expansion stroke cylinder is equal to or larger than the predetermined crank angle, the intake stroke cylinder is supplied with the intake air supercharged by the electric supercharger and the expansion stroke cylinder In addition, since the engine 1 is started by injecting and igniting the fuel in the intake stroke cylinder, even if it is difficult to start the engine 1 only by the combustion pressure of the expansion stroke cylinder, the combustion pressure of the intake stroke cylinder is applied to the engine 1 Can be started.

  On the other hand, if it is determined in step S32 that the engine speed Ne is not equal to or greater than the start determination value Ne, it is determined that the engine 1 could not be started by fuel injection and ignition into the cylinder for some reason, and the process proceeds to step S28. In step S28, the engine 1 is started by operating the starter motor 30 and cranking the engine 1, and the electric supercharger 26 is stopped in the next step S26, and then the start control routine in the current control cycle is executed. finish.

Therefore, in the present embodiment, the crank angle sensor 38 corresponds to the rotational speed detecting means.
Although not shown in the flowcharts of FIGS. 2 and 3, the ECU 42 determines whether the engine speed Ne is equal to or higher than the start determination value Ne in step S24 or after the engine 1 is cranked by the starter motor 30. In accordance with the engine operation control routine, the fuel injection and ignition necessary for the operation of the engine 1 are sequentially executed for each subsequent cylinder.

By the way, if it is determined in step S16 that the crank angle after the top dead center corresponding to the piston position of the expansion stroke cylinder is not equal to or greater than the predetermined crank angle, the volume in the expansion stroke cylinder is relatively small and injection into the cylinder is performed. The process proceeds to step S30 on the assumption that the spent fuel can be sufficiently mixed with air.
In step S30, fuel is injected from the fuel injection valve 2 into the expansion stroke cylinder. The fuel injection at this time is also executed based on the information stored in step S8 and step S10, and the fuel injection amount is calculated based on the in-cylinder air amount calculated from the piston position of the expansion stroke cylinder. Based on the quantity, fuel is injected into the expansion stroke cylinder.

In the next step S32, after a predetermined time has elapsed since the fuel injection in step S30, the ignition plug 4 ignites the fuel in the expansion stroke cylinder. The piston 12 of the expansion stroke cylinder is pushed down by the combustion pressure generated by the ignition of the fuel, and the engine 1 is started.
At this time, the intake valve 8 and the exhaust valve 14 of the expansion stroke cylinder are closed, the inside of the cylinder is sealed, and the fuel and air are sufficiently mixed. The combustion pressure necessary for starting the engine 1 is ensured by injection and ignition. Therefore, in this case, fuel injection and ignition to the intake stroke cylinder are not performed.

  After the engine 1 is started in this way, when the process proceeds to the next step S24, the engine rotational speed Ne detected based on the detection signal of the crank angle sensor 38 after a predetermined time has elapsed since the ignition was performed in step S32 is started. It is determined whether or not the determination value is Ne or more. If it is determined in step S32 that the engine speed Ne is greater than or equal to the start determination value Ne, it is assumed that the engine 1 has started normally, and the process proceeds to step S26 to stop the electric supercharger 26. In this case, since the electric supercharger 26 is already in the stopped state, substantially no processing is performed in step S26, and the start control routine in the current control cycle is terminated.

  On the other hand, if it is determined in step S32 that the engine speed Ne is not equal to or greater than the start determination value Ne, the process proceeds to step S28 as described above, and the engine 1 is cranked by operating the starter motor 30. The electric supercharger 26 is stopped at the next step S26, and in this case as well, the electric supercharger 26 is already in a stopped state, so substantially no processing is performed at step S26. Instead, the start control routine in the current control cycle is terminated.

In this case as well, after the engine speed Ne is equal to or higher than the start determination value Nes in step S24 or after the engine 1 is cranked by the starter motor 30, the ECU 42 performs each subsequent operation by another engine operation control routine. Fuel injection and ignition necessary for the operation of the engine 1 are sequentially performed on the cylinders.
As described above, when the crank angle after the top dead center indicating the piston position of the expansion stroke cylinder is smaller than the predetermined crank angle, the engine 1 can be started only by fuel injection and ignition in the expansion stroke cylinder. Therefore, fuel injection and ignition to the intake stroke cylinder are not performed, and the electric supercharger 26 is not operated, so that it is possible to suppress fuel consumption and reduce battery usage.

In addition, when the coolant temperature Tw indicating the temperature of the engine 1 is equal to or lower than the determination temperature Tws, or when the engine rotation speed Ne is not equal to or higher than the start determination value Ne for fuel injection and ignition into the cylinder, the starter motor Since the engine 1 is cranked and started at 30, the engine 1 can be reliably started.
Although the description of the engine starting device according to one embodiment of the present invention has been completed above, the present invention is not limited to the above-described embodiment.

For example , in the above-described embodiment, when the coolant temperature Tw of the engine 1 is equal to or lower than the determination temperature Tws, the engine 1 is started by cranking the starter motor 30 without performing fuel injection and ignition into the cylinder. Also at this time, it is also possible to perform the start by the combustion pressure by supplying the intake air supercharged by the electric supercharger 26, injecting the fuel into the cylinder, and igniting.
By doing so, it is possible to reduce the power consumed by the starter motor 30. On the other hand, when starting with only the starter motor 30 as in the above embodiment, it is possible to reduce power consumption and fuel consumption by the electric supercharger.

Further, in the above-described embodiment, the present invention is applied to the engine 1 that performs the idle stop control. However, the present invention is applied to an engine that is started and stopped only by operating the ignition switch without performing the idle stop control. Also, the present invention can be applied.
Furthermore, in the above-described embodiment, the present invention is applied to an in-line four-cylinder engine. However, the engine 1 is not limited to this, and at least one cylinder such as a six-cylinder engine or an eight-cylinder engine has an expansion stroke. If the engine is such that at least one of the remaining cylinders is in the intake stroke, the present invention can be applied.

1 is an overall configuration diagram of an engine starter according to an embodiment of the present invention. It is a flowchart which shows a part of starting control performed with the starting device of FIG. It is a flowchart which shows the remainder of the starting control performed with the starting device of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Engine 2 Fuel injection valve 4 Spark plug 26 Electric supercharger 30 Starter motor 36 Water temperature sensor (temperature detection means)
38 Crank angle sensor (piston position detection means, rotation speed detection means)
42 ECU (control means, cylinder discrimination means)

Claims (3)

In an engine starter in which at least one of a plurality of cylinders is in an expansion stroke and at least one of the remaining cylinders is in an intake stroke,
A fuel injection valve provided in each of the plurality of cylinders for injecting fuel into the cylinder;
A spark plug provided in each of the plurality of cylinders for igniting fuel injected into the cylinder;
An electric supercharger provided in the intake passage of the engine and driven by an electric motor to supercharge intake air of the engine;
Cylinder discrimination means for discriminating each of the cylinders in the expansion stroke and the cylinders in the intake stroke when the engine is stopped;
Piston position detecting means for detecting the position of each piston of the plurality of cylinders;
The cylinder that was in the intake stroke when the engine was stopped is supplied with the intake air supercharged by the electric supercharger, and the cylinder that was in the expansion stroke and the cylinder that was in the intake stroke when the engine was stopped Control means for starting the engine by supplying fuel from a fuel injection valve and igniting the supplied fuel with the spark plug ;
The control means expands when the engine is stopped when the piston of the cylinder in the expansion stroke when the engine is stopped is a position corresponding to a crank angle less than a predetermined crank angle after top dead center. An engine starter characterized by starting the engine by supplying fuel to only the cylinders in the stroke and igniting them . A starter motor capable of cranking the engine;
A temperature detecting means for detecting the temperature of the engine;
2. The engine starter according to claim 1, wherein the control unit starts the engine using the starter motor when the engine temperature detected by the temperature detection unit is equal to or lower than a predetermined temperature. A starter motor capable of cranking the engine;
A rotation speed detecting means for detecting the rotation speed of the engine;
When the engine rotation speed detected by the rotation speed detection means does not increase above a predetermined value after starting the engine by supplying fuel into the cylinder and igniting the fuel, the control means 2. The engine starting device according to claim 1, wherein the engine is started using a starter motor.

Images