Engine control unit

Abstract

To provide an engine control device capable of improving startability of an engine while suppressing an impact on tension applied to a belt.SOLUTION: An engine control device includes: an engine 2; a motor 3 for starting the engine 2; a crank pulley 21 provided in a crank shaft of the engine 2; a motor pulley 31 provided in a rotating shaft of the motor 3; a belt 6 wound around the crank pulley 21 and the motor pulley 31; an upper tensioner 4 adjusting tension of the upper side of the belt 6; a lower tensioner 5 adjusting tension of the lower side of the belt 6; and a control section 7 performing regenerative braking by applying torque in a direction reverse to the rotating direction of the engine 2 by using the motor 3 during stop of the engine 2 and limiting the torque of the motor 3 when the engine 2 is started after performing the regenerative braking.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an engine control device. [Background technology]

[0002] Patent Document 1 describes a method for starting an engine by wrapping a belt around a crank pulley provided on the crankshaft of the engine and a motor-generator pulley provided on the motor-generator.

[0003] Patent Document 1 discloses that, due to concerns that large fluctuations in belt tension could have a negative impact on the durability of the belt, when the motor-generator is driven to start the engine, the motor-generator is driven at a torque lower than the maximum torque for a predetermined period of time after startup. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-328911 Summary of the Invention [Problem to be solved by the invention]

[0005] However, if the motor generator is driven at low torque for a certain period of time each time the engine is started, it will take longer to start the engine, which could result in a decrease in engine startability.

[0006] However, the tension applied to the belt depends on the vehicle's running state immediately before the engine is stopped, so there is room for improvement.

[0007] SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an engine control device that can improve the startability of the engine while minimizing the effect on the tension applied to the belt. [Means for solving the problem]

[0008] In order to solve the above problems, the present invention provides an engine control device for an engine including a motor for starting the engine, a crank pulley provided on a crankshaft of the engine, a motor pulley provided on a rotary shaft of the motor, a belt wound around the crank pulley and the motor pulley, and a tensioner for adjusting the tension of the belt, The tensioner is configured to adjust the tension of the belt by pressing a tensioner pulley, which is rotatably provided at the tip of a tensioner arm that rotates around a rotation axis, against the belt by a force applied to the tensioner arm, and includes an angle sensor that detects the angle of the tensioner arm about the rotation axis from a predetermined reference position in the direction in which the belt moves when the engine is started; The engine of a control unit that performs regenerative braking by applying torque from the motor in a direction opposite to the rotation direction of the engine when the vehicle is stopped; and, When starting the engine after performing the regenerative braking, the control unit Based on the angle detected by the angle sensor when the engine is stopped, This limits the torque of the motor. [Effects of the Invention]

[0009] In this way, according to the present invention, it is possible to improve the startability of the engine while suppressing the influence on the tension applied to the belt. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic diagram of an engine control device according to an embodiment of the present invention. [Figure 2] FIG. 2 is a flowchart showing the procedure of the engine restart control process of the engine control device according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0011] An engine control device according to one embodiment of the present invention is an engine control device for an engine that includes a motor for starting the engine, a crank pulley attached to the engine's crankshaft, a motor pulley attached to the motor's rotating shaft, a belt wound around the crank pulley and the motor pulley, and a tensioner for adjusting the tension of the belt, and is equipped with a control unit that performs regenerative braking by applying torque from the motor in the opposite direction to the rotational direction of the engine when the engine is stopped, and the control unit is configured to limit the torque of the motor when starting the engine after performing regenerative braking.

[0012] As a result, the engine control device according to one embodiment of the present invention can improve the startability of the engine while suppressing the effect on the tension applied to the belt. [Example]

[0013] An engine control device according to an embodiment of the present invention will be described in detail below with reference to the drawings.

[0014] In FIG. 1, a vehicle 1 equipped with an engine control device according to an embodiment of the present invention includes an engine 2, a motor 3, and a control unit .

[0015] The engine 2 has a plurality of cylinders. In this embodiment, the engine 2 is configured to perform a series of four strokes for each cylinder: an intake stroke, a compression stroke, an expansion stroke, and an exhaust stroke. A crank pulley 21 is provided on the crankshaft of the engine 2.

[0016] The motor 3 functions as an electric motor that rotates when supplied with electric power to rotate the engine 2, and also functions as a generator that converts the rotational force input from the crankshaft into electric power. The motor 3 is configured, for example, by an ISG (Integrated Starter Generator). A motor pulley 31 is provided on the rotating shaft of the motor 3.

[0017] A belt 6 is wound around the crank pulley 21 and the motor pulley 31. The crank pulley 21 and the motor pulley 31 are connected to each other via the belt 6.

[0018] Between the crank pulley 21 and the motor pulley 31, there are provided an upper tensioner 4 as a tensioner that adjusts the tension on the upper side of the belt 6, and a lower tensioner 5 as a tensioner that adjusts the tension on the lower side of the belt 6. In this embodiment, two tensioners, the upper tensioner 4 and the lower tensioner 5, are provided, but a configuration in which only one of them is provided is also acceptable.

[0019] The upper tensioner 4 generates a predetermined tension in the belt 6 by pressing a tensioner pulley 43, which is rotatably mounted at the tip of a tensioner arm 42 that rotates around a rotating shaft 41, against the belt 6 by the force applied to the tensioner arm 42.

[0020] The lower tensioner 5 generates a predetermined tension in the belt 6 by pressing a tensioner pulley 53, which is rotatably mounted at the tip of a tensioner arm 52 that rotates around a rotation shaft 51, against the belt 6 by the force applied to the tensioner arm 52.

[0021] The upper tensioner 4 has, for example, α U An angle sensor 44 is provided to detect the upper tensioner angle, which is the tensioner angle indicated by the arrow in the direction in which the belt 6 moves when the engine 2 is started.

[0022] The lower tensioner 5 has, for example, α L An angle sensor 54 is provided to detect the lower tensioner angle, which is the angle of the tensioner arm 52 in the direction in which the belt 6 moves when the engine 2 is started, as indicated by the arrow.

[0023] The control unit 7 is composed of a computer unit equipped with a CPU (Central Processing Unit), RAM (Random Access Memory), ROM (Read Only Memory), flash memory for storing various backup data, input ports, and output ports.

[0024] The ROM of this computer unit stores various constants, various maps, and the like, as well as a program for causing the computer unit to function as the control unit 7.

[0025] That is, the CPU executes the program stored in the ROM using the RAM as a work area, and these computer units function as the control unit 7 in this embodiment.

[0026] To the input port of the control unit 7, various sensors including the angle sensor 44 and the angle sensor 54 described above are connected. The output port of the control unit 7 is connected to various control targets including the motor 3 described above.

[0027] The control unit 7 performs idle stop restart control, which stops the engine 2 when a predetermined automatic stop condition is met, and restarts the engine 2 when a predetermined restart condition is met.

[0028] The automatic stop conditions are, for example, that the vehicle speed is equal to or lower than a predetermined speed, the brake pedal is depressed, and the battery charge capacity is equal to or higher than a predetermined value.

[0029] On the other hand, the restart condition may be, for example, that the shift position is appropriate for starting, that the brake pedal is not depressed, or any combination of these conditions is satisfied.

[0030] In this embodiment, when stopping the engine 2, the control unit 7 performs regenerative braking by applying torque from the motor 3 in the direction opposite to the rotation direction of the engine 2 to brake the engine.

[0031] In FIG. 1, the direction of the arrow indicating forward rotation is the rotation direction of the engine 2, and the direction of the arrow indicating reverse rotation is the rotation direction opposite to the rotation of the engine 2.

[0032] Due to the regenerative braking described above, the belt 6 moves in the reverse direction, the belt 6 on the upper tensioner 4 side moves in the direction in which it is tensioned, and the tensioner pulley 43 is pulled toward the motor pulley 31 side.

[0033] Conversely, the belt 6 on the lower tensioner 5 side moves in the loosening direction, so that the tensioner pulley 53, which has a large damping force, is pushed toward the crank pulley 21 side.

[0034] This movement causes the tensioner arm 42 to move to an upper tensioner angle α U The next time the engine 2 is started, when the belt 6 moves toward the crank pulley 21, the inertial force increases, and the stopper interference angle β of the tensioner arm 42 decreases, as shown by the dotted line in the figure. U , and the tension of the belt 6 may become excessive.

[0035] Therefore, the control unit 7 limits the torque of the motor 3 when starting the engine 2 after performing regenerative braking.

[0036] For example, the control unit 7 limits the torque of the motor 3 in stages as the upper tensioner angle detected by the angle sensor 44 decreases. For example, the control unit 7 reduces the limit value of the torque of the motor 3 in stages as the upper tensioner angle detected by the angle sensor 44 decreases.

[0037] For example, the control unit 7 limits the torque of the motor 3 in stages as the lower tensioner angle detected by the angle sensor 54 decreases. For example, the control unit 7 reduces the limit value of the torque of the motor 3 in stages as the lower tensioner angle detected by the angle sensor 54 decreases.

[0038] For example, if the upper tensioner angle detected by the angle sensor 44 is less than a predetermined angle, the control unit 7 limits the torque of the motor 3 to a predetermined value or less, and if the angle detected by the angle sensor 44 is greater than or equal to the predetermined angle, the control unit 7 does not limit the torque of the motor 3.

[0039] For example, if the lower tensioner angle detected by the angle sensor 54 is less than a predetermined value, the control unit 7 limits the torque of the motor 3 to a predetermined value or less, and if the angle detected by the angle sensor 54 is greater than or equal to the predetermined value, the control unit 7 does not limit the torque of the motor 3.

[0040] The upper tensioner angle and the lower tensioner angle are detected when the engine 2 is stopped.

[0041] The engine restart control process performed by the engine control device according to this embodiment configured as described above will be described with reference to Fig. 2. The engine restart control process described below is started after the automatic stop condition for the engine 2 is met and the engine 2 is automatically stopped.

[0042] In step S1, the control unit 7 detects the upper tensioner angle and the lower tensioner angle. After executing the process of step S1, the control unit 7 executes the process of step S2.

[0043] In step S2, the control unit 7 determines whether the upper tensioner angle or the lower tensioner angle is smaller than a predetermined value.

[0044] If the control unit 7 determines that the upper tensioner angle or the lower tensioner angle is smaller than the predetermined value, the control unit 7 executes the process of step S3. If the control unit 7 determines that the upper tensioner angle and the lower tensioner angle are not smaller than the predetermined value, the control unit 7 executes the process of step S4.

[0045] In step S3, the control unit 7 commands the motor 3 to start with low torque the next time it is started. After executing the process of step S3, the control unit 7 executes the process of step S5.

[0046] In step S4, the control unit 7 commands the motor 3 to start with maximum torque the next time it is started. After executing the process of step S4, the control unit 7 executes the process of step S5.

[0047] In step S5, the control unit 7 determines whether or not the restart condition for the engine 2 is met.

[0048] If it is determined that the restart condition of the engine 2 is satisfied, the control unit 7 executes the process of step S6. If it is determined that the restart condition of the engine 2 is not satisfied, the control unit 7 executes the process of step S5.

[0049] In step S6, the control unit 7 causes the motor 3 to output the commanded torque, thereby restarting the engine 2. After executing the process of step S6, the control unit 7 ends the engine restart control process.

[0050] In this way, in this embodiment, the control unit 7 limits the torque of the motor 3 when starting the engine 2 after performing regenerative braking.

[0051] As a result, when the engine 2 is started after regenerative braking, the motor torque is suppressed, thereby preventing the tension applied to the belt 6 from becoming excessive.

[0052] Furthermore, the control unit 7 limits the torque of the motor 3 in stages as the upper tensioner angle detected by the angle sensor 44 or the lower tensioner angle detected by the angle sensor 54 becomes smaller.

[0053] As a result, as the belt 6 moves in the direction of tension due to regenerative braking, the torque of the motor 3 at the start of the engine 2 is gradually reduced, thereby preventing the tension on the belt 6 from becoming excessive at the start of the engine 2.

[0054] Furthermore, when the upper tensioner angle detected by the angle sensor 44 or the lower tensioner angle detected by the angle sensor 54 is less than a predetermined angle, the control unit 7 limits the torque of the motor 3 to a predetermined value or less.

[0055] As a result, when the value of the upper tensioner angle or the lower tensioner angle is less than a predetermined value, the torque of the motor 3 when the engine 2 is started is suppressed, and it is possible to prevent excessive tension from being generated in the belt 6. There is a risk that the tension applied to the belt 6 will become excessive when the engine 2 is started, so this is suppressed.

[0056] In this embodiment, the positions of the tensioner pulleys 43 and 53 are detected by the angle sensors 44 and 54, but a displacement sensor may be used to detect the positions of the tensioner arms 42 and 52, or the tensioner pulleys 43 and 53, and the belt 6. In this way, the system can be adapted to the number of tensioners and the routing of the belt 6 without being affected.

[0057] In this embodiment, an example has been described in which the control unit 7 performs various judgments and calculations based on various sensor information, but this is not limited to this. The vehicle 1 may be provided with a communication unit capable of communicating with an external device such as an external server, and various judgments and calculations may be performed by the external device based on the detection information of the various sensors transmitted from the communication unit. The judgment results and calculation results may be received by the communication unit, and various controls may be performed using the received judgment results and calculation results.

[0058] While an embodiment of the present invention has been disclosed, it will be apparent to one skilled in the art that modifications may be made thereto without departing from the scope of the present invention, and it is intended that all such modifications and equivalents be included in the following claims. [Explanation of symbols]

[0059] 1 vehicle 2 engines 3 motors 4 Upper tensioner (tensioner) 5 Lower tensioner (tensioner) 6 Belt 7 Control Unit 21 Crank pulley 31 Motor pulley 41, 51 Rotation axis 42, 52 Tensioner arm 43, 53 Tensioner pulley 44, 54 angle sensor

Claims

1. a motor for starting the engine; a crank pulley provided on a crankshaft of the engine; a motor pulley provided on a rotation shaft of the motor; a belt wound around the crank pulley and the motor pulley; a tensioner that adjusts the tension of the belt, The tensioner is configured to adjust the tension of the belt by pressing a tensioner pulley, which is rotatably provided at the tip of a tensioner arm that rotates around a rotation axis, against the belt by a force applied to the tensioner arm, an angle sensor that detects an angle of the tensioner arm about a rotation axis from a predetermined reference position in a direction in which the belt moves when the engine is started; a control unit that performs regenerative braking by applying torque by the motor in a direction opposite to the rotation direction of the engine when the engine is stopped, The control unit is an engine control device that, when starting the engine after performing the regenerative braking, limits the torque of the motor based on the angle detected by the angle sensor when the engine is stopped.

2. An engine control device as described in claim 1, wherein the control unit gradually reduces the torque limit value of the motor as the angle detected by the angle sensor becomes smaller.

3. An engine control device as described in claim 1 or claim 2, wherein the control unit limits the torque of the motor to a predetermined value or less when the angle detected by the angle sensor is less than a predetermined angle.

4. 4. The engine control device according to claim 1, wherein the tensioners include an upper tensioner that adjusts the tension of an upper side of the belt, and a lower tensioner that adjusts the tension of a lower side of the belt.

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