JP2010159708A - Control device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control device for an internal combustion engine, capable of stopping a crankshaft in a just-estimated position, by restraining a sudden load variation in a generator caused by reduction in a power generation quantity. <P>SOLUTION: This control device of the internal combustion engine has a stopping processing means for stopping the internal combustion engine, and a power generation control means for controlling the power generation quantity of the generator. The power generation control means enables the generator to perform a predetermined power generation quantity by increasing the power generation ratio of the generator in response to reduction in an engine speed of the internal combustion engine after starting the stop processing of the internal combustion engine by the stopping processing means. Since the control device for the internal combustion engine is constituted in this way, the stopping position of the crankshaft can be surely estimated without varying the power generation quantity, that is, a load in the generator. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to power generation control of a generator when an internal combustion engine is stopped.

  It is known that when a vehicle stops due to a signal or the like and the engine is in an idling state or the like, the operation of the engine is stopped to improve fuel consumption or reduce exhaust gas emissions. Thereafter, when the driver operates the transmission or performs an action that leads to starting such as releasing the brake, the engine is immediately started. Conventionally, this has been done by rotating the crankshaft of the engine by the operation of a starter motor (cell motor).

  By the way, in recent years, a so-called direct start system is considered in which an air-fuel mixture is ignited and combusted in a cylinder, and the engine is started by applying a rotational force to the crankshaft using the combustion energy. This method of directly starting the internal combustion engine has features such as almost no power consumption of the storage battery, less burden on the starting motor, and smooth operation of the engine than the method of operating the starting motor. Have.

  On the other hand, in order to start by burning the air-fuel mixture in the cylinder, it is necessary to stop the engine in a state where it can be started by cylinder combustion in advance. That is, when the crankshaft stops rotating, it is temporarily determined that the first cylinder is in the middle of the expansion stroke. Then, the first cylinder is set as the starting cylinder, and fuel is injected from the fuel injection device into the intake passage in the intake process of the latest starting cylinder where the crankshaft stops rotating. Then, an air-fuel mixture is introduced into the starting cylinder and the top dead center of the compression process is exceeded by inertial rotation of the crankshaft. And while moving a piston to an expansion stroke, operation of an engine is stopped, without making it transfer to an exhaust process.

When starting the engine, spark is discharged from the spark plug to the starting cylinder, the air-fuel mixture in the starting cylinder is ignited and burned, the piston is pushed down by the combustion energy, and rotational force is applied to the crankshaft. Start up. (See Patent Document 1.)
JP 2006-336572 A

  However, accessories such as an air conditioner compressor, a generator, and a cooling water pump are connected to the crankshaft of the engine via a belt. The crankshaft only rotates with an inertial force when fuel injection or ignition by the spark plug is stopped. On the other hand, the load on the auxiliary machines connected to the crankshaft varies depending on the operating conditions. Therefore, the position where the crank shaft stops depends on the load from the accessories.

  Therefore, an attempt was made to quickly stop the crankshaft at a predetermined position by setting the operation amount of each auxiliary machine to the maximum and setting the maximum load from the auxiliary equipment to the crankshaft. However, even if the air conditioner is set to operate at maximum, if the room temperature is low, the electromagnetic clutch cuts off the connection to the compressor and stops the compression operation. Even if the power generator is operated to the maximum, the power generation amount is reduced by the action of the regulator and the load applied to the crankshaft is reduced when the power consumption of the vehicle is low. As described above, even when the operation amount of the auxiliary machinery is maximized, the load applied to the crankshaft is reduced on the way, and the stop position of the crankshaft cannot be accurately controlled.

  On the other hand, the operation amount of each auxiliary machine was minimized, and it was considered to rotate only by the inertia mass of the crankshaft. However, when the amount of electric power consumed by the vehicle is large, the voltage of the storage battery decreases and the generator automatically resumes power generation. As a result, a new load is generated from the generator to the crankshaft, and even in this case, the stop position of the crankshaft cannot be accurately controlled.

  As described above, the auxiliary machinery, particularly the generator, cannot keep the operating state constant regardless of whether the power generation amount is maximized or minimized, and the load applied to the crankshaft varies. As a result, the stop position of the crankshaft could not be accurately controlled.

  An object of the present invention is to solve the above-mentioned problems, to provide a control device for an internal combustion engine that can suppress a sudden load fluctuation of a generator accompanying a decrease in power generation amount and can stop a crankshaft at an estimated position. And

  In order to solve the above-described problems, the present invention has a control device for an internal combustion engine configured as follows.

  1. The control device for an internal combustion engine has stop processing means for stopping the internal combustion engine and power generation control means for controlling the power generation amount of the generator, and the power generation control means performs stop processing of the internal combustion engine by the stop processing means. After the start, the power generation rate of the generator is increased with a decrease in the rotational speed of the internal combustion engine, and the generator is allowed to perform a predetermined power generation amount.

  2. The control apparatus for an internal combustion engine according to claim 1, wherein the power generation control means lowers the power generation rate of the generator to a predetermined value before the power generation control means performs the stop processing of the internal combustion engine. The stop process is performed after the internal combustion engine speed has stabilized.

  According to this configuration, by reducing the power generation rate and reducing the power generation amount before stopping the internal combustion engine, even if the power generation amount increases due to an increase in the power generation rate, the occurrence of load fluctuations due to the power generation limitation of the generator is suppressed. The crankshaft can be stopped at a predetermined position.

  In the control apparatus for an internal combustion engine according to the third or second aspect, the predetermined value of the power generation rate of the generator is set to a value that allows the pressure value in the intake passage to be set to a predetermined value regardless of the electric load of the vehicle.

  According to this configuration, when the stop process is started, the pressure in the intake passage is constant regardless of the amount of electric power used by the vehicle. Therefore, the stop process can be performed more accurately, and the crankshaft is placed at a predetermined position. You can stop.

  In the control device for an internal combustion engine according to any one of 4, 1 to 3, the increase in the power generation rate by the power generation control means is set such that the lower limit value is a power generation rate that generates a voltage at which the generator does not start charging the storage battery. Is a power generation rate that generates a voltage that does not limit the amount of power generated by the generator.

  According to this configuration, it is possible to suppress the occurrence of inadvertent load fluctuations such as the operation of the generator for charging the storage battery and the suppression of the operation of the generator for preventing overcharge, and the crankshaft is set at a predetermined position. You can stop.

The control apparatus for an internal combustion engine according to the present invention has the following effects.
When the stop process of the internal combustion engine is performed, the power generation rate of the generator is increased with the decrease in the rotational speed of the internal combustion engine, so that the decrease in the amount of power generation due to the decrease in the rotational speed of the internal combustion engine is compensated with the power generation rate of the generator Thus, it is possible to suppress a rapid load fluctuation of the generator due to a decrease in the power generation amount, and to stop the crankshaft at the estimated position.

  An embodiment of a control device for an internal combustion engine according to the present invention will be described with reference to the drawings. FIG. 1 shows a combustion chamber portion of the engine 10. The engine 10 is a fuel injection type spark ignition type internal combustion engine with an intake passage that includes a fuel injection device that uses gasoline as a main fuel and injects fuel into the intake passage. The engine 10 is a naturally aspirated engine, but may be a supercharged engine equipped with a turbocharger or other supercharger. Further, a carburetor type may be used instead of the fuel injection type.

  The combustion chamber portion of the engine 10 includes a cylinder head 12, a piston 14, a cylinder block 16 and the like as shown in FIG. The cylinder block 16 has a cylinder 18 inside. The number of cylinders 18 formed in the cylinder block 16 is not particularly limited. A piston 14 is provided in the cylinder 18 so as to be reciprocally movable.

  The piston 14 is connected to the crankshaft 36 via a connecting rod 38. A cylinder head 12 is fixed to the upper surface of the cylinder block 16 with bolts (not shown).

  The cylinder head 12 has a recess 20 for a combustion chamber on the lower surface. The recess 20 has a triangular cross section, and forms a combustion chamber 26 of the engine 10 in a space defined by the recess 20, the top surface 22 of the piston 14, and the inner surface of the cylinder 18. Moreover, the inside of such a compartment is also called a cylinder.

  The cylinder head 12 is provided with an intake passage 24 and an exhaust passage 28. The intake passage 24 is connected to an air cleaner (not shown) on the upstream side, and an intake valve 42 is provided at an opening (not shown) facing the combustion chamber 26. A fuel injection device 34 is provided in the intake passage 24.

  The fuel injection device 34 is a fuel injection device in the intake passage having an injection hole at the tip and having a valve mechanism (both not shown) inside. A fuel pipe 56 from the fuel tank 52 and a signal from the control device 58. Line 60 is connected. The fuel tank 52 includes a fuel pump 62, and the fuel in the fuel tank 52 is pumped into the fuel pipe 56 at a predetermined pressure via the fuel pump 62.

  The fuel injection device 34 is attached with the injection hole facing the intake passage 24, and when the valve mechanism is operated in accordance with a signal sent via the signal line 60, the fuel sent from the fuel tank 52 is taken in. The fuel is injected into the passage 24 at a predetermined pressure. Note that the fuel may be pressurized by the fuel injection device 34 and injected into the intake passage 24. The term “injection” basically refers to radiating fuel in the form of a mist, but it may be injected in the form of a liquid column. Further, the mounting position of the fuel injection device 34, the injection direction, and the like are not particularly limited.

  The exhaust passage 28 communicates with the combustion chamber 26 via an exhaust valve 44, and an oxidation catalyst 29 and a particulate filter 31 are connected to the downstream side of the exhaust passage 28. The oxidation catalyst 29 and the particulate filter 31 may not be provided.

  The intake valve 42 and the exhaust valve 44 are slidably attached to the cylinder head 12. The intake valve 42 is provided with an intake side valve mechanism 46, and the exhaust valve 44 is provided with an exhaust side valve mechanism 48. . The intake side valve mechanism 46 and the exhaust side valve mechanism 48 operate in conjunction with the rotation of the crankshaft 36 to drive the intake valve 42 and the exhaust valve 44 in the axial direction. As a result, the intake passage 24 and the exhaust passage 28 are opened and closed at a predetermined time with respect to the combustion chamber 26 as the engine 10 is driven.

  A spark plug 30 is attached to the cylinder head 12. The spark plug 30 has an electrode portion at the tip, and is attached to the cylinder head 12 substantially at the center of the upper portion of the combustion chamber 26 with the electrode portion facing the combustion chamber 26. The ignition plug 30 is connected to the ignition mechanism 40 and discharges at an appropriate ignition timing by the action of the ignition mechanism 40. Note that the spark plug 30 may be attached to another position instead of the center of the combustion chamber 26.

  The crankshaft 36 has a shaft end exposed from the engine 10, a pulley attached to the shaft end, a drive belt (none shown), a compressor, a cooling water pump (none shown), A generator 37 is connected. The cylinder block 16 is provided with a crank angle sensor 72. The crank angle sensor 72 measures the crank angle of the crankshaft 36 and sends the result to the control device 58 via the signal line 70.

  The compressor is a refrigerant compressor of an air conditioner, and is connected to a pulley of the crankshaft 36 through an electromagnetic clutch, and can be appropriately disconnected from the crankshaft 36 by the action of the electromagnetic clutch. The cooling water pump is a pump for sending cooling water for cooling the engine into the engine 10 and is directly connected to the pulley of the crankshaft 36. The load generated by the cooling water pump is known in the entire rotation region of the crankshaft 36. Note that an electric motor may be connected to the cooling water pump, and the cooling water pump may be electrically driven.

  The generator 37 is an ordinary vehicle generator called an alternator, and includes a regulator 39 and a rectifier (not shown). The generator 37 is directly connected to the crankshaft 36 via a drive belt. The power generation amount of the generator 37 is adjusted according to the amount of power used, the amount of charge of a storage battery (not shown), and the like by the action of the regulator 39.

  Furthermore, a power generation amount adjustment unit 41 is connected to the generator 37. The power generation amount adjusting unit 41 is connected to the control device 58 through the signal line 43, and the power generation rate is controlled by the control device 58 in a stop process to be described later. The power generation rate at that time is shown in FIG. In FIG. 2, the horizontal axis indicates time, and the vertical axis indicates the target power generation rate E, the actual power generation rate F, the storage battery voltage, and the rotation speed of the crankshaft 36 according to (a) to (d) from above. A is the time when fuel injection is stopped. The power generation rate of the power generator 37 is a ratio of the power generation amount to the maximum power generation amount of the power generator 37, and can be arbitrarily set from 0% to 100%.

  As shown in FIG. 2A, the target power generation rate E in the stop process decreases to a predetermined value at the time A when the fuel injection from the fuel injection device 34 is stopped, and from there, the rotation speed of the crankshaft 36 As shown in (d), it is set so that it gradually rises.

  2 (a) and 2 (b) is a range in which the voltage of the vehicle decreases to a voltage that requires charging of the storage battery when the power generation rate is set in this range. When the power generation rate is set in this range, the vehicle voltage is increased to a voltage that is required to reduce the amount of power generated by the generator 37. The target power generation rate E is set near the middle between the shaded portion 200 and the shaded portion 210.

  In other words, when the generator 37 is operated according to the target power generation rate E, the power generator 37 first generates power according to the power generation rate that increases as the power generation rate decreases to a predetermined value and then increases as the rotation speed of the crankshaft 36 decreases. To do. As a result, the generator 37 generates a predetermined amount of power generation regardless of the electrical load of the vehicle and the state of charge of the storage battery. For this reason, a predetermined and previously known load is always applied from the generator 37 to the crankshaft 36 in such a power generation state.

  The control device 58 is provided with a direct start function including a stop method as a main function in addition to control for normally operating the engine 10 during traveling of the vehicle.

  Next, the direct start function of the engine 10 and the stopping method at that time will be described with reference to the time chart of FIG. 2 and the flowchart of FIG. In addition, starting the engine 10 directly means that the air-fuel mixture introduced into the cylinder is ignited and burned, the rotational pressure is applied to the crankshaft 36 using the combustion pressure, and the engine 10 is started. The direct start function is mainly used when the engine 10 is started after being stopped for a short time, but not when the engine is stopped for a short time but when the engine is stopped at night and the engine is started next morning. It may be used.

  First, when the vehicle is traveling normally and the coolant temperature reaches a predetermined temperature and the engine 10 is in a stable operating state, the control device 58 performs idle stop control. That is, when the vehicle is temporarily stopped due to a signal waiting or the like, the operation of the engine 10 is stopped, the engine 10 is automatically started at the time of start, and the vehicle is started by the engine 10.

  Specifically, when the vehicle stops, the driver puts the transmission in a neutral state (neutral), and when the side brake or foot brake is continued, the control device 58 temporarily stops the vehicle waiting for a signal or the like. The engine 10 is determined to start after a while (step 101), and the engine 10 is stopped in a state where it can be directly started (step 102).

  Next, stop processing that can be directly started will be described. If the control device 58 has decided to start the stop process (step 102), the electromagnetic clutch of the compressor is disconnected, and the connection between the compressor and the crankshaft 36 is released. Further, the fuel injection from the fuel injection device 34 and the spark discharge by the spark plug 30 are stopped (step 103). Then, the control device 58 receives a crank angle signal of the crankshaft 36 from the crank angle sensor 72, and when the crankshaft 36 is stopped from the rotation angle of the crankshaft 36, each cylinder of the engine 10 takes in intake, compression, Whether expansion (combustion) or exhaust process is to be performed is determined.

  Further, the control device 58 controls the power generation rate of the generator 37 according to the target power generation rate E as shown in FIG. 2 (step 104), and stops the crankshaft 36. That is, when the fuel injection is stopped at point A, the generator 37 first decreases the power generation rate to a predetermined value, and then the rotational speed of the crankshaft 36 decreases as shown in (d). Along with the increase (step 104), power generation is performed according to the target power generation rate E.

  By controlling the generator 37 according to such a target power generation rate E, the voltage of the vehicle does not become lower than the required value (12V) for charging the storage battery as shown in FIG. Since the voltage (14 V or higher) is not obtained, the power generation amount of the generator 37 is not increased, and the power generation amount of the generator 37 is not limited.

  FIG. 2B shows the actual power generation rate F. As shown in the figure, before the fuel injection is stopped, the power generation rates are different depending on the magnitude of the electric load (indicated by a solid line and a one-dot chain line), but are matched by a decrease in the power generation rate, and during the stop process Since the power generation amount of the power generator 37 is not increased or the power generation amount of the power generator 37 is not limited, the power generation rate is substantially equal to the target power generation rate E after the fuel injection is stopped.

  Therefore, the power generator 37 does not cause a large fluctuation in the power generation rate as shown in FIG. In addition, the power generation rate is generated without entering any of the hatched portions 200 and 210. In addition, the connection of auxiliary equipment such as a compressor is cut off. Accordingly, a predetermined load is always applied from the generator 37 to the crankshaft 36, and the crankshaft 36 receives a predetermined damping force from the time when the stop operation is started, and the rotation decreases. Therefore, the crankshaft 36 is surely stopped at a previously estimated position, that is, the piston 14 of each cylinder is stopped in the state as estimated.

  Since the crankshaft 36 is stopped in the predetermined state as described above, the control device 58 causes the fuel injection device 34 to perform fuel injection based on the estimated stoppage state of the crankshaft 36, and the crankshaft 36 is stopped. Before starting, a predetermined air-fuel mixture is introduced into the starting cylinder, and the crankshaft 36 is stopped. As a result, the engine 10 is stopped in a state where it can be directly started (step 105).

  After that, if it is determined that the driver has performed a start operation, the control device 58 starts the engine 10. The driver's start operation is a predetermined operation related to starting the vehicle, for example, returning the parking brake, putting the gear in first gear, or stepping on the accelerator pedal a little. If such an operation is confirmed, the air-fuel mixture in the starting cylinder is ignited and burned by the spark plug 30. As a result, the crankshaft 36 is urged in the forward rotation direction, and the engine 10 is started using the rotational force acting on the crankshaft 36. The starting method is the same as the conventional method.

  As described above, in the case of an internal combustion engine with a direct start function, the load applied from the generator 37 to the crankshaft 36 can always be kept at a predetermined value regardless of the state of electric use of the vehicle and the state of charge of the storage battery. . Therefore, it is possible to reliably grasp the behavior from the start of the stop process that can be directly started until the crankshaft 36 stops rotating. Therefore, the air-fuel mixture can be introduced into the starting cylinder, the crankshaft 36 can be reliably stopped, and the stopping that can be directly started can be accurately performed. As a result, the direct start can be accurately performed.

  Next, another example of the stopping method will be described. In this second example, when the stop process that can be started directly is determined, the power generation rate of the generator 37 is reduced to a predetermined value before the stop of fuel injection or the stop of ignition is executed.

  Hereinafter, the second stopping method will be described with reference to the time chart of FIG. 4 and the flowchart of FIG. The configuration of the internal combustion engine is the same as that of the engine 10 described above. The content shown in the time chart of FIG. 4 is the same content as the time chart of FIG. 2 described above. In the figure, point A is the time for stopping fuel injection, and point B is the time for reducing the power generation rate.

  When it is determined that the vehicle is temporarily stopped (step 110) and a stop process that can be started directly is determined (step 111), the power generation rate of the generator 37 is determined from point B as shown in FIG. The value is lowered to a predetermined value (step 112). By reducing the power generation rate to a predetermined value at point B, the power generation rates (shown by the solid line and the alternate long and short dash line) that differed depending on the amount of electricity used by the vehicle as shown in (b) before point B are substantially the same. Is set to the value of Thereby, the intake pressure in the intake passage 24 that was different before the point B (normally negative pressure if there is no supercharging) can be set to the same value.

  When the rotation speed of the crankshaft 36, that is, the intake pressure in the intake passage 24 is stabilized (step 113), the fuel injection is stopped at the point A (step 114). Then, the stop process is performed from the point A as described above. In step 115, the power generation rate is gradually increased. If the engine 10 is stopped, the stop process is terminated (step 116).

  Since the point A is later in time than the point B, the pressure in the intake passage is constant regardless of the amount of electric power used by the vehicle at the time when the stop process is actually started. The stop process started by stopping the fuel injection can be performed more accurately, and the crankshaft 36 can be stopped at a predetermined position. Therefore, the stop that can be directly started can be surely performed, and the engine 10 can be directly started stably.

  In the above-described embodiment, the internal combustion engine with the direct start function that introduces the air-fuel mixture into the start cylinder when the internal combustion engine is stopped has been described. However, in order to stop the crankshaft at a predetermined position, the normal internal combustion engine is used. Can be applied.

It is sectional drawing which shows one Embodiment of the internal combustion engine with a variable valve mechanism concerning this invention. It is a time chart regarding a stop processing operation. It is a flowchart regarding a stop processing operation. It is a time chart regarding the stop processing operation of another example. It is a flowchart regarding the stop processing operation of another example.

DESCRIPTION OF SYMBOLS 10 ... Engine 14 ... Piston 24 ... Intake passage 26 ... Combustion chamber 30 ... Spark plug 34 ... Fuel injection device 36 ... Crankshaft 37 ... Generator 39 ... Regulator 40 ... Ignition mechanism 41 ... Power generation amount adjustment part 58 ... Control device 72 ... Crank angle sensor 200 ... hatched portion 210 ... hatched portion

Claims (4)

In a control device for an internal combustion engine, comprising: a generator coupled to a crankshaft of the internal combustion engine; stop processing means for stopping the internal combustion engine; and power generation control means for controlling the power generation amount of the generator.
The power generation control means starts the stop process of the internal combustion engine by the stop processing means, and then increases the power generation rate of the generator in accordance with a decrease in the rotational speed of the internal combustion engine. A control apparatus for an internal combustion engine, characterized in that The power generation control means reduces the power generation rate of the generator to a predetermined value before performing the stop processing of the internal combustion engine by the stop processing means,
2. The internal combustion engine according to claim 1, wherein the stop processing unit performs the stop process after the power generation rate of the generator is reduced to a predetermined value by the power generation control unit and the rotation speed of the internal combustion engine is stabilized. Engine control device.   The internal combustion engine according to claim 2, wherein the predetermined value of the power generation rate of the generator is a value that allows the pressure value in the intake passage to be set to a predetermined value regardless of an electric load of the vehicle. Control device.   The increase in the power generation rate by the power generation control means is such that the lower limit value is a power generation rate that generates a voltage at which the generator does not start charging the storage battery, and the upper limit value is limited to the power generation amount of the generator. The control apparatus for an internal combustion engine according to any one of claims 1 to 3, wherein the power generation rate is such that no voltage is generated.

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