Starting device for internal combustion engines

Abstract

To provide a starting device for an internal combustion engine, which can improve the startability.SOLUTION: A starting device for an internal combustion engine comprises a first starting unit that is connected to the internal combustion engine by a belt and outputs driving force for starting the internal combustion engine, a second starting unit that is connected to the internal combustion engine by a gear and outputs driving force for starting the internal combustion engine, and a control unit that starts the internal combustion engine using the first starting unit and the second starting unit. When the force for rotating the internal combustion engine is equal to or greater than a predetermined magnitude, the control unit starts the internal combustion engine using the second starting unit without using the first starting unit.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a starting device for an internal combustion engine. [Background technology]

[0002] BACKGROUND ART There is known a technique for starting an internal combustion engine by cranking the internal combustion engine with an electric motor (motor generator) (see Patent Document 1, etc.). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-182239 Summary of the Invention [Problem to be solved by the invention]

[0004] For example, if the reaction force acting from the internal combustion engine is large, starting may fail. Therefore, an object of the present invention is to provide a starting device for an internal combustion engine that can improve startability. [Means for solving the problem]

[0005] The above object can be achieved by a starting device for an internal combustion engine comprising a first starting unit connected to an internal combustion engine by a belt and outputting a driving force for starting the internal combustion engine, a second starting unit connected to the internal combustion engine by a gear and outputting a driving force for starting the internal combustion engine, and a control unit that starts the internal combustion engine using the first starting unit and the second starting unit, wherein when the force for rotating the internal combustion engine is equal to or greater than a predetermined magnitude, the control unit starts the internal combustion engine using the second starting unit rather than the first starting unit.

[0006] After the internal combustion engine fails to autonomously return from a stop, if either the air pressure is equal to or greater than a predetermined value or the steering angle of the power steering is equal to or greater than a predetermined amount, the force for rotating the internal combustion engine is equal to or greater than a predetermined magnitude, and the control unit may start the internal combustion engine using the second starting unit without using the first starting unit.

[0007] The first starting unit may have a first pulley, the second starting unit may have a first gear, the internal combustion engine may have a second pulley and a second gear, and the first starting unit may be connected to the internal combustion engine by having the belt stretched between the first pulley and the second pulley, and the second starting unit may be connected to the internal combustion engine by having the first gear and the second gear come into contact.

[0008] The first starting unit may be a motor generator, and the second starting unit may be a starter. [Effects of the Invention]

[0009] A starting device for an internal combustion engine that can improve startability can be provided. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic diagram illustrating a starting device according to an embodiment. [Figure 2] FIG. 2 is a flowchart illustrating the start-up process. DETAILED DESCRIPTION OF THE INVENTION

[0011] The starting device for an internal combustion engine according to the present embodiment will be described below with reference to the drawings. However, the dimensions and ratios of the various parts in the drawings may not be exactly the same as those in reality. In addition, some details may be omitted in some drawings.

[0012] FIG. 1 is a schematic diagram illustrating a starting device 100 according to an embodiment. The starting device 100 is mounted on, for example, a hybrid vehicle. The starting device 100 includes a motor generator (MG) 10 (first starting unit), a starter 12 (second starting unit), and an ECU (Electronic Control Unit) 14 (control unit). The starting device 10 starts an internal combustion engine 16. The internal combustion engine 16 is, for example, a four-cylinder engine that burns fuel to generate driving force. Each of the four cylinders is provided with a fuel injection valve 17. A rotation speed sensor 45 detects the rotation speed of the internal combustion engine 16. A pressure sensor 46 detects, for example, pressure outside the vehicle.

[0013] The MG 10 is connected to the internal combustion engine 16, generates driving force, and assists the internal combustion engine 16. The MG 10 generates electric power and charges a battery (not shown). The MG 10 has a pulley 20 (first pulley). The pulley 20 is connected to the shaft of the MG 10. The internal combustion engine 16 has a pulley 22 (second pulley). The pulley 22 is connected to the crankshaft of the internal combustion engine 16. The pulleys 20 and 22 are disc-shaped parts. Pulley 22 The diameter of the pulley 20 diameter, e.g. pulley 20 The diameter of the pulley 20 is at least two or three times the diameter of the pulley 22. A belt 24 is stretched between the pulley 20 and the pulley 22.

[0014] The starter 12 is, for example, a motor, and is connected to the internal combustion engine 16. The starter 12 has a gear 30 (first gear). The gear 30 is connected to the shaft of the starter 12. The internal combustion engine 16 has a gear 32 (second gear). The gear 32 is connected to the crankshaft. The gears 30 and 32 are ring-shaped gears, each having a plurality of teeth on its outer circumferential surface. Gear 32 The diameter of the gear 30 diameter, e.g. gear 30 The diameter of the gear 30 is more than ten times the diameter of the gear 32.

[0015] The power steering 40 is a hydraulic device and includes a pulley 42. A belt 44 is stretched between the pulley 42 and the pulley 22 of the internal combustion engine 16. The power steering 40 includes, for example, a pump, a tank, an oil passage, a steering wheel, etc. (not shown). Force is transmitted from the crankshaft to the power steering 40 through the pulley 22, the belt 44, and the pulley 42. The force operates the pump, which discharges oil. The hydraulic pressure assists the driver's steering force on the steering wheel. The greater the steering angle of the steering wheel, the higher the hydraulic pressure output by the power steering 40.

[0016] The ECU 14 is a control device that includes a central processing unit (CPU), random access memory (RAM), read-only memory (ROM), and other storage devices, and performs various controls by executing programs stored in the ROM and storage devices. The ECU 14 acquires the steering angle of the power steering 40. The ECU 14 acquires the rotation speed detected by the rotation speed sensor 45 and the pressure detected by the pressure sensor 46.

[0017] The ECU 14 controls the MG 10, the starter 12, and the internal combustion engine 16. The ECU 14 controls the on / off and rotation speed of the MG 10. The ECU 14 controls the on / off and rotation speed of the starter 12. The ECU 14 controls the amount of fuel injected from the fuel injection valve 17 and the timing of injection. The ECU 14 starts and stops the internal combustion engine 16. The ECU 14 stops the internal combustion engine 16, for example, by stopping the supply of fuel from the fuel injection valve 17.

[0018] The ECU 14 starts the internal combustion engine 16 using the MG 10 or the starter 12. The ECU 14 rotates the MG 10. The power generated by the MG 10 is transmitted to the crankshaft of the internal combustion engine 16 via a pulley 20, a belt 24, and a pulley 22. The crankshaft is rotated by the power of the MG 10, and the internal combustion engine 16 starts. The ECU 14 rotates the starter 12. The power generated by the starter 12 is transmitted to the crankshaft via gears 30 and 32. The crankshaft is rotated by the power of the starter 12, and the internal combustion engine 16 starts.

[0019] The ECU 14 performs an idling stop. For example, when the opening of an accelerator (not shown) falls below a predetermined amount, or when the amount of brake depression exceeds a predetermined amount, the ECU 14 automatically stops the internal combustion engine 16. For example, when the opening of the accelerator exceeds a predetermined amount, the ECU 14 automatically starts the internal combustion engine 16.

[0020] If the rotation speed of the stopped internal combustion engine 16 is equal to or greater than a predetermined value, the ECU 14 performs autonomous recovery of the internal combustion engine 16. The ECU 14 causes the fuel injection valve 17 to inject fuel. After fuel injection, the rotation speed of the internal combustion engine 16 increases and the internal combustion engine 16 starts. In this case, the autonomous recovery is successful. On the other hand, if the rotation speed does not increase sufficiently after fuel injection, the autonomous recovery is unsuccessful.

[0021] If autonomous recovery fails, fuel remains inside the cylinders of the internal combustion engine 16. The temperature inside the cylinders is higher than the outside air. This makes it easy for the pressure inside the cylinders to increase. Because the pressure is high, the force (reaction force) required to rotate the crankshaft also increases.

[0022] For example, underground, such as in a mine, the air pressure may be higher than normal pressure (air pressure at the surface). The pressure inside the cylinders also increases, increasing the reaction force. When the steering angle is large, such as when the steering wheel is turned stationary, the oil pressure of the power steering 40 increases. The power steering 40 is operated by the output from the internal combustion engine 16. Therefore, when the oil pressure increases, the pressure in the cylinders of the internal combustion engine 16 also increases, increasing the reaction force.

[0023] If the reaction force is high, the starting of the internal combustion engine 16 by the MG 10 is likely to fail. Therefore, the ECU 14 starts the internal combustion engine 16 using the starter 12.

[0024] 2 is a flowchart illustrating the start-up process. The ECU 14 determines whether autonomous starting of the internal combustion engine 16 has failed (step S10). If the rotation speed is equal to or greater than a predetermined value after fuel injection, the autonomous starting is successful. If the rotation speed is less than the predetermined value, the autonomous starting is unsuccessful. If the determination in step S10 is negative (No), the ECU 14 determines whether the outside air pressure P is equal to or greater than a predetermined pressure Pth (step S12). If the determination in step S12 is negative, the ECU 14 determines whether the power steering 40 is in a stationary steering state (step S14).

[0025] If the determination is negative in all of steps S10, S12, and S14, the ECU 14 starts the internal combustion engine 16 using the MG 10 (step S16). If the determination is positive (Yes) in any of steps S10, S12, and S14, the ECU 14 starts the internal combustion engine 16 using the starter 12 without using the MG 10 (step S18). After step S16 or S18, the processing in FIG. 2 ends.

[0026] According to this embodiment, torque is transmitted from the MG 10 to the internal combustion engine 16 by the belt 24. On the other hand, torque is transmitted from the starter 12 to the internal combustion engine 16 by the gears 30 and 32. The starter 12 can transmit torque more effectively than the MG 10. When the force required to rotate the internal combustion engine 16 is equal to or greater than a predetermined magnitude, the ECU 14 starts the internal combustion engine 16 by the starter 12. Since the starter 12 is used to start the internal combustion engine 16 when the reaction force is large, starting is less likely to fail. This improves the startability of the internal combustion engine 16.

[0027] For example, after the autonomous return fails, if either the air pressure P is equal to or greater than a predetermined value Pth or the steering angle of the power steering 40 is equal to or greater than a predetermined amount (for example, when the engine is turned stationary), the pressure inside the cylinder increases. The reaction force also increases. The ECU 14 starts the internal combustion engine 16 using the starter 12. This improves startability. In situations other than those described above where the reaction force increases, the engine is started using the starter 12.

[0028] Starting with Starter 12 after a failed start with MG10 Start As shown in Figure 2, when the reaction force increases, the engine is started by the starter 12 without attempting to start by the MG 10. This improves responsiveness.

[0029] A belt 24 is wound between a pulley 20 of the MG 10 and a pulley 22 of the internal combustion engine 16. A gear 30 of the starter 12 and a gear 32 of the internal combustion engine 16 are in contact with each other. Compared to the torque transmitted by the belt 24, a larger torque can be transmitted by the two meshed gears 30 and 32. This improves starting performance.

[0030] By making the diameter of the gear 30 smaller than the diameter of the gear 32, it is possible to transmit a large torque. 30 Diameter and gear 32 The ratio of the diameter to the shaft diameter should be 1:10 or more. This increases torque and improves starting performance.

[0031] To increase the torque transmitted by the belt 24, for example, a belt with greater friction than a normal belt can be used. The torque can also be increased by enlarging the pulley. However, this increases costs. Furthermore, starting using the starter 12 increases vibration compared to starting using the MG 10. Starting using the MG 10 is performed in situations other than those in which the reaction force increases (step S16 in Figure 2). Vibration can be suppressed. Since the situations in which starting using the MG 10 is used are limited, there is no need to increase the size of the pulley, etc. Increases in costs are suppressed. In situations in which the reaction force is large, starting using the starter 12 can be prioritized over suppressing vibration (step S18).

[0032] Although the preferred embodiments of the present invention have been described in detail above, the present invention is not limited to such specific embodiments, and various modifications and variations are possible within the scope of the gist of the present invention as described in the claims. [Explanation of symbols]

[0033] 10 MG, 12 starter, 14 ECU, 16 internal combustion engine, 17 fuel injector, 20, 22, 42 pulley, 24 belt, 30, 32 gear, 45 rotation speed sensor, 46 pressure sensor

Claims

1. a first starting unit connected to the internal combustion engine by a belt and configured to output a driving force for starting the internal combustion engine; a second starting unit connected to the internal combustion engine by a gear and configured to output a driving force for starting the internal combustion engine; a control unit that starts the internal combustion engine using the first starting unit and the second starting unit, after the internal combustion engine has failed to autonomously return from a stop, if either the air pressure is equal to or greater than a predetermined value or the steering angle of the power steering is equal to or greater than a predetermined amount, the force for rotating the internal combustion engine is equal to or greater than a predetermined magnitude, When the force for rotating the internal combustion engine is less than the predetermined magnitude, the control unit starts the internal combustion engine using the first starting unit, An internal combustion engine starting device in which, when the force for rotating the internal combustion engine is equal to or greater than the predetermined magnitude, the control unit starts the internal combustion engine using the second starting unit without attempting to start the internal combustion engine using the first starting unit.

2. the first starting section has a first pulley; the second starting unit has a first gear, the internal combustion engine has a second pulley and a second gear; The belt is wound around the first pulley and the second pulley, thereby connecting the first starting unit to the internal combustion engine, When the first gear and the second gear come into contact with each other, the second starting unit is connected to the internal combustion engine, The diameter of the second pulley is larger than the diameter of the first pulley, 2. A starting device for an internal combustion engine according to claim 1, wherein the diameter of said second gear is larger than the diameter of said first gear.

3. the first starting unit is a motor generator, 3. The internal combustion engine starting device according to claim 1, wherein the second starting unit is a starter.

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