JP2015033914A - Hybrid system, hybrid vehicle and power transmission method for hybrid system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hybrid system that enables shortening of time to traveling start by reducing generation torque of a starter required at start of an internal combustion engine and at restart from idling stop, a hybrid vehicle and a power transmission method for the hybrid system.SOLUTION: In a hybrid system including an internal combustion engine 10 and a motor generator 21, the motor generator 21 is directly or indirectly connected to a crank shaft 15 of the internal combustion engine 10. During operation to stop the internal combustion engine 10, a hybrid control device 41 for controlling the motor generator 21 performs control by rotating the crank shaft 15 by driving force of the motor generator 21 so as to form a crank angle that causes smaller friction of the rotation of the crank shaft 15 compared to a crank angle when the crank shaft 15 is stopped.

Description

  The present invention relates to a hybrid system, a hybrid vehicle, and a power transmission method of the hybrid system, and more particularly, a hybrid system capable of reducing a generated torque of a starter required when starting an internal combustion engine and restarting an idling stop. The present invention relates to a hybrid vehicle and a power transmission method for a hybrid system.

  In a hybrid vehicle (HEV) equipped with both an internal combustion engine and a motor generator, the motor generator is driven by the output of the internal combustion engine to generate power, and the generated power is charged into a battery or charged into this battery. The motor generator is driven by electric power to assist the output of the internal combustion engine. When driving a motor generator with this internal combustion engine, it is necessary to transmit the driving force of the internal combustion engine to the motor generator.

  For this power transmission, several methods have been proposed. For example, an electric motor (motor generator) is provided between the engine (internal combustion engine) and the transmission, and the electric motor is connected to the engine drive shaft ( A hybrid vehicle connected to a crankshaft has been proposed (see, for example, Patent Document 1).

  On the other hand, when starting the internal combustion engine, the crankshaft is rotationally driven using a starter, and the piston in the cylinder (cylinder) is accelerated and moved to a position where fuel can be injected and a rotational speed where ignition is possible.

  However, when the engine before starting is stopped, after stopping the fuel injection, the crankshaft rotates while moving the piston by inertia but stops due to the friction of the internal combustion engine. This stop is normally stopped at a crank angle position where the friction is maximum.

  Therefore, at the time of starting after this stop, the cranking starts from the state where the friction is at the maximum crank angle position, the torque generated by the starter required at the time of starting becomes large, and the energy loss at the time of starting is large. There is.

JP 2013-75540 A

  The present invention has been made in view of the above, and an object of the present invention is to provide a hybrid system, a hybrid vehicle, and a hybrid system, a hybrid vehicle, which can reduce the generated torque of a starter that is required when starting an internal combustion engine and restarting an idling stop. And a power transmission method for a hybrid system.

  In order to achieve the above object, a hybrid system of the present invention is a hybrid system having an internal combustion engine and a motor generator, wherein the motor generator is connected directly or indirectly to a crankshaft of the internal combustion engine, and the motor generator The hybrid control device that controls the engine rotates the crankshaft by the driving force of the motor generator during the stop operation of the internal combustion engine, and determines the crank angle when the crankshaft is stopped. It is configured to perform control so that the position where the friction is minimized or a position in the vicinity thereof.

  According to this configuration, it is possible to reduce the generated torque of the starter required when starting the internal combustion engine and restarting the idling stop, thereby shortening the time until the start of traveling. Therefore, the traveling characteristics of a hybrid vehicle equipped with this hybrid system can be improved.

  The minimum position or a position near the minimum position is a crank angle position where the rotational friction is in a range close to the minimum and minimum. For example, the maximum friction when no fuel is injected and the friction width of the minimum friction are, for example, 20 It is a range in which the friction becomes smaller than the target friction larger than the minimum friction by about%, preferably about 10%.

  And if the hybrid vehicle for achieving said objective mounts said hybrid system, it can have an effect similar to said hybrid system.

  A hybrid system power transmission method for achieving the above-described object is a hybrid system power transmission method including an internal combustion engine and a motor generator, which is directly applied to a crankshaft of the internal combustion engine when the internal combustion engine is stopped. Alternatively, the crankshaft is rotated by the driving force of the motor generator that is indirectly connected, and the crank angle when the crankshaft is stopped is the position where the friction of rotation of the crankshaft is minimized or a position near it. It is the method characterized by making.

  According to this method, it is possible to reduce the torque generated by the starter required at the time of starting the internal combustion engine and restarting the idling stop, thereby shortening the time until the start of traveling. Therefore, the traveling characteristics of a hybrid vehicle equipped with this hybrid system can be improved.

  According to the hybrid system, the hybrid vehicle, and the power transmission method of the hybrid system of the present invention, it is possible to reduce the starter generation torque required when starting the internal combustion engine and restarting the idling stop, And the running characteristics of the hybrid vehicle can be improved.

It is a figure showing composition of a hybrid system and a hybrid vehicle of an embodiment of the invention. It is a figure which shows the structure of the hybrid system provided with the connection / disconnection apparatus for crankshafts, and a hybrid vehicle.

  Hereinafter, a hybrid system, a hybrid vehicle, and a power transmission method of the hybrid system according to embodiments of the present invention will be described with reference to the drawings.

  A hybrid system 2 in the form of the embodiment of FIG. 1 is a hybrid system having an engine (internal combustion engine) 10 and a motor generator (M / G) 21. Here, the hybrid system 2 is described as being mounted on a hybrid vehicle (HEV: hereinafter referred to as a vehicle) 1, but is not necessarily limited to that mounted on the vehicle.

  As shown in FIG. 1, the engine 10 of the hybrid system 2 of this embodiment includes an engine body (ENG) 11, an exhaust passage 12, a turbocharger 13, and an exhaust gas purification device ( A post-processing device) 14. The exhaust gas purification device 14 purifies NOx (nitrogen oxide), PM (particulate matter), etc. in the exhaust gas discharged from the engine 10. The purified exhaust gas is released into the atmosphere via a muffler (not shown) or the like.

  A motor generator 21 is connected to the crankshaft 15 of the engine 10 directly or indirectly. In the configuration of FIG. 1, a motor generator 21 is indirectly connected to the crankshaft 15 of the engine 10. That is, a CVT (continuously variable transmission mechanism: ratio variable mechanism) 16 is provided directly connected to the crankshaft 15 of the engine 10, and the motor generator 21 is connected to the CVT 16. That is, the first pulley (first power transmission unit) 16a of the CVT 16 is provided on the crankshaft 15 of the engine 10, and the second pulley (second power transmission unit) 16b of the CVT 16 is provided on the motor generator 21. The power transmission between the crankshaft 15 and the motor generator 21 is performed via the first pulley 16a and the second pulley 16b. An endless belt or chain (power transmission member) 16c is hung between the first pulley 16a and the second pulley 16b. From the crankshaft 15, the first pulley 16a, the power transmission member 16c, and the second pulley. Power is transmitted to the motor generator 21 via 16b, and conversely to the crankshaft 15 from the motor generator 21 via the second pulley 16b, the power transmission member 16c and the first pulley 16a.

  In this CVT 16, the power transmission member 16c is applied to a pair of the first pulley 16a and the second pulley 16b, and the widths of the individual pulleys 16a and 16b are changed to contact the pulleys 16a and 16b with the power transmission member 16c. The position is changed, and if the width is expanded and the position where the power transmission member 16c contacts is inward (closer to the shaft), the diameter becomes smaller. Conversely, the position where the power transmission member 16c contacts with the power transmission member 16c is decreased. The diameter is increased if the outer side is moved (if the outer side is moved). And by performing control to change the expansion and contraction of the widths of the two pulleys 16a and 16b to be opposite to each other by a hydraulic or electric mechanism (not shown) by electronic control, the power transmission member 16c is not slackened. Shifting can be performed continuously.

  When the CVT 16 is configured such that the transmission 31 is connected to one of the crankshafts 15 and the CVT 16 is connected to the other of the crankshafts 15 in the engine 10, the CVT 16 is connected to the transmission 31 with respect to the engine 10. Therefore, it is not necessary to provide the CVT 16 between the engine 10 and the transmission 31. For this reason, motor generators can be easily installed even for combinations of existing engines and transmissions (powertrains) that do not consider hybrid systems, and the types of powertrains to which hybrid systems can be applied are expanded. Can be easily done.

  In this case, in the prior art, on the opposite side of the transmission with respect to the engine, an auxiliary machine such as a cooling fan, a cooling water pump, or a lubricating oil pump that obtains driving force from the crankshaft is arranged. These auxiliary machines are preferably electrified so as to be driven by the electric power generated by the motor generator without obtaining the driving force directly from the crankshaft. This increases the freedom with respect to the layout of the auxiliary machinery, and further has the advantage that the engine output without load loss due to the auxiliary machinery can be used as the driving force depending on the situation.

  The motor generator 21 that is a part of the power system 20 generates power by receiving the driving force of the engine 10 as a generator, or generates regenerative power by generating regenerative power such as the braking force of the vehicle 1. And driving as a motor, transmitting the driving force to the crankshaft 15 of the engine 10 to assist the driving force (output: torque) of the engine 10.

  The electric power generated by the power generation is converted by the inverter (INV) 23 via the wiring 22 and charged in the first battery (charger: B1) 24A. When driving the motor generator 21, the electric power charged in the first battery 24 </ b> A is converted by the inverter 23 and supplied to the motor generator 21.

  In the configuration of FIG. 1, a DC-DC converter (CON) 25 and a second battery (B2) 24B are further provided in series with the first battery 24A. In the DC-DC converter 25, for example, the voltage is dropped to 12 V and charged to the second battery 24B, and the auxiliary battery cooling fan 26A, cooling water pump 26B, Electric power is supplied to the lubricating oil pump 26C and the like.

  In a hybrid vehicle (hereinafter referred to as a vehicle) 1 equipped with the hybrid system 2, the power of the engine 10 is transmitted to a transmission 31 of the power transmission system 30, and further, a propulsion shaft (propeller shaft) is transmitted from the transmission 31. It is transmitted to the operating device (differential gear) 33 through 32, and transmitted to the wheel 35 from the operating device 33 through the drive shaft (drive shaft) 34. Thereby, the motive power of the engine 10 is transmitted to the wheel 35 and the vehicle 1 travels.

  On the other hand, regarding the power of the motor generator 21, the power charged in the first battery 24A is supplied to the motor generator 21 via the inverter 23, and the motor generator 21 is driven by this power to generate power. The power of the motor generator 21 is transmitted to the crankshaft 15 via the CVT 16, transmitted through the power transmission path of the engine 10, and transmitted to the wheels 35.

  Thereby, the power of the motor generator 21 is transmitted to the wheels 35 together with the power of the engine 10, and the vehicle 1 travels. During regeneration, the regenerative power of the wheels 35 or the regenerative power of the engine 10 is transmitted to the motor generator 21 through the reverse path, and the motor generator 21 can generate power.

  Also, a hybrid system control device 41 is provided, and the operating state such as the rotational speed Ne and the load Q of the engine 10, the operating state such as the rotational speed Na of the motor generator 21, and the charging of the first battery 24A and the second battery 24B. While monitoring the quantity (SOC) state, the CVT 16, the motor generator 21, the inverter 23, the DC-DC converter 25, and the like are controlled. The hybrid system control device 41 is normally configured to be incorporated in an overall control device 40 that controls the engine 10 and the vehicle 1. The overall control device 40 controls the combustion in the cylinder, the turbocharger 13, the exhaust gas purification device 14, the cooling fan 26A of the auxiliary machine, the cooling water pump 26B, the lubricating oil pump 26C and the like in the control of the engine 10. Yes.

  Further, when the crankshaft connecting / disconnecting device 17 is provided between the crankshaft 15 and the motor generator 21 as in the hybrid system 2A and the hybrid vehicle 1A shown in FIG. Is not used as a motor or a generator, it is more preferable because the crankshaft connecting / disconnecting device 17 can be disconnected and the engine 10 can be operated without the influence of friction on the motor generator 21 side. In particular, if the crankshaft connecting / disconnecting device 17 is provided between the crankshaft 15 and the first pulley 16a, the engine 10 can be operated without the influence of friction on the CVT 16 side in addition to the motor generator 21 side. it can.

  In the present invention, the hybrid control device 41 that controls the motor generator 21 rotates the crankshaft 15 by the driving force of the motor generator 21 when the engine 10 is stopped. It is configured such that θ is controlled so that the friction Tf of rotation of the crankshaft 15 is the minimum position θmin or a position in the vicinity thereof (θ1 to θ2).

  As a result, the crankshaft 15 when the engine 10 is stopped is stopped at the crank angle θmax at which the friction Tf is maximized, and a starter (not shown) necessary for the next start or the start again such as an idling stop is generated. By avoiding the torque Ts from increasing, the torque Ts generated by the starter required at the time of starting the engine 10 and at the time of restarting, such as idling stop, is reduced, thereby shortening the time until the start of traveling.

  The minimum position θmin or a position in the vicinity thereof (θ1 to θ2) is a position of the crank angle θ in which the rotation friction Tf of the crankshaft 15 is within the minimum and minimum range, for example, when no fuel is injected. The friction width ΔTf (= Tfmax−Tfmin) of the maximum friction Tfmax and the minimum friction Tfmin is, for example, about 20%, preferably about 10%, and the friction Tf is larger than the target friction Tfo (= Tfmin + 0.2 × ΔTf) larger than the minimum friction Tfmin. Is the target range (θ1 to θmin to θ2) such that becomes smaller.

  This control is performed by detecting the crank angle θ immediately before the stop of the engine 10 by a crank angle sensor (not shown) normally provided for controlling the engine 10 or an engine angle detection sensor (not shown) provided separately. The rotation of the motor generator 21 is controlled so that the crank angle θ is within a target range (θ1 to θ2) set in advance through experiments or the like.

  At this time, when the CVT 16 is provided, the same motor generator 21 is obtained by changing the diameter ratio Rd (= Db / Da) of the working diameter Db of the second pulley 16b to the working diameter Da of the first pulley 16a. The driving force Tc and the crank angle (rotation angle) θ transmitted to the crankshaft 15 can be changed even when the driving force Tm and the rotation angle θm are equal to each other. It is preferable to perform stop control of the crankshaft 15 after achieving an optimal state for control of the stop position.

  The power transmission method of the hybrid system in this embodiment is a power transmission method of the hybrid system 2 having the engine 10 and the motor generator 21, and directly or directly to the crankshaft 15 of the engine 10 when the engine 10 is stopped. The crankshaft 15 is rotated by the driving force of the indirectly connected motor generator 21, and the crank angle θ of the crankshaft 15 is a position θmin where the frictional Tf of the rotation of the crankshaft 15 is minimum or a position in the vicinity thereof (θ1 to θ1). θ2).

  According to the hybrid system 2, 2A, hybrid vehicle 1, 1A, and hybrid system power transmission method according to the embodiment of the present invention, the starter generation torque Ts required when the engine 10 is started and when the idling stop is restarted. Can be reduced to shorten the time until the start of traveling, and the traveling characteristics of the hybrid vehicles 1 and 1A can be improved.

1, 1A vehicle (hybrid vehicle: HEV)
2, 2A Hybrid system 10 Engine (Internal combustion engine)
DESCRIPTION OF SYMBOLS 11 Engine main body 12 Exhaust passage 13 Turbo supercharger 14 Exhaust gas purification apparatus 15 Crankshaft 16 CVT (continuously variable transmission mechanism)
17 Connecting / disconnecting device 20 for crankshaft Electric power system 21 Motor generator (M / G)
22 Wiring 23 Inverter (INV)
24A First battery (B1)
24B Second battery (B2)
25 DC-DC converter (CON)
26A Cooling fan (auxiliary machine)
26B Cooling water pump (auxiliary machine)
26C Lubricating oil pump (auxiliary machine)
30 Power transmission system 31 Transmission
32 Propeller shaft
33 Differential (differential gear)
34 Drive shaft
35 Wheel 40 Overall control device 41 Hybrid system control device Da Actual working diameter Db of the first pulley Rd Actual working diameter Rd of the second pulley Rd CVT diameter ratio Tc Driving force transmitted to the crankshaft Tf Crankshaft rotation friction Tfo Target friction Tfmax Maximum friction Tfmin Minimum friction Tm Motor generator drive force (drive torque)
Ts Generated torque of starter θ Crank angle of crankshaft θm Motor generator rotation angle θmax Position of maximum crankshaft friction θmin Position of minimum crankshaft rotation θ1-θ2 Position near minimum position ΔTf Friction width

Claims (3)

In a hybrid system having an internal combustion engine and a motor generator, the motor generator is connected directly or indirectly to the crankshaft of the internal combustion engine,
The hybrid control device that controls the motor generator rotates the crankshaft by the driving force of the motor generator during the stop operation of the internal combustion engine, and the crank angle when the crankshaft is stopped A hybrid system configured to perform control so that crankshaft rotation friction is a small crank angle.   A hybrid vehicle equipped with the hybrid system according to claim 1. In a power transmission method of a hybrid system having an internal combustion engine and a motor generator,
During the stop operation of the internal combustion engine, the crankshaft is rotated by the driving force of the motor generator directly or indirectly connected to the crankshaft of the internal combustion engine, and the crank angle when the crankshaft is stopped A power transmission method for a hybrid system, wherein the crankshaft has a small crank angle so that the friction of rotation of the crankshaft is small.

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