JP6651727B2 - Hybrid vehicle and control method thereof - Google Patents

Description

  The present invention relates to a hybrid vehicle and a control method thereof, and more particularly, to a hybrid that can improve regenerative efficiency during high-speed running, can easily be converted from an existing non-hybrid vehicle to a hybrid vehicle, and can increase the life of a foundation brake. The present invention relates to a vehicle and a control method thereof.

  2. Description of the Related Art In recent years, a hybrid vehicle (hereinafter, referred to as “HEV”) including a hybrid system having an engine and a motor generator that are combined and controlled in accordance with the driving state of the vehicle has attracted attention from the viewpoint of improving fuel efficiency and environmental measures. . In this HEV, the driving power is assisted by the motor generator when the vehicle is accelerating or starting, while the regenerative power is generated by the motor generator during inertial running or braking (for example, see Patent Document 1).

  In the HEV described above, the motor generator is usually connected from the engine side of the transmission to the drive system of the vehicle, that is, to the drive system of the vehicle via the transmission. Therefore, when the vehicle enters the inertia traveling state during the high speed traveling of the HEV (for example, 50 to 90 km / h), the transmission is shifted to the high speed stage, and the power is transmitted through the high speed gear. As a result, the regenerative braking torque in the motor generator becomes small, deviating from the high efficiency point of power generation. Therefore, there is a problem that it is difficult to improve the efficiency of regenerative power generation.

  Further, in this HEV, a layout of a power train component of an existing engine-only vehicle (that is, a non-hybrid vehicle having no hybrid system) needs to be significantly changed in order to dispose the motor generator. There is also a problem that it is not easy to convert an existing non-hybrid vehicle into an HEV and convert it.

  In order to solve such a problem, the inventor connects the propeller shaft of the HEV and the rotation axis of the motor generator via a reduction mechanism having the rotation axis of the motor generator as an input axis and the propeller shaft as an output axis. Devised to do.

  However, in the above-described HEV, the life of a foundation brake such as a foot brake cannot be said to be sufficiently long.

JP 2002-238105 A

  SUMMARY OF THE INVENTION An object of the present invention is to provide a hybrid vehicle capable of improving the regenerative efficiency at the time of high-speed running compared to the related art, easily converting an existing non-hybrid vehicle to a hybrid vehicle, and improving the life of a foundation brake, and a control thereof. It is to provide a method.

A hybrid vehicle of the present invention that achieves the above object connects a hybrid system having a diesel engine and a motor generator, a transmission connected to the diesel engine via a clutch, and a differential that drives the transmission and wheels. In a hybrid vehicle including a propeller shaft and a control device, a reduction mechanism that uses the propeller shaft and the rotation shaft of the motor generator as an input shaft and the rotation shaft of the motor generator as an output shaft. And the control device is configured to control the speed of the hybrid vehicle when the vehicle speed of the hybrid vehicle is within a predetermined setting range and the transmission has a predetermined number of gears. When the brake pedal is depressed, the output value of the motor generator is controlled to the maximum value within a preset output range, regenerative power generation is performed by the motor generator, and the depression amount of the brake pedal is set in advance. If the threshold value is smaller than the threshold value, the clutch is disengaged , the hybrid vehicle is decelerated by a braking force by a foot brake according to an amount of depression of the brake pedal, and a braking force by the motor generator, and the brake pedal When the stepping amount of the brake pedal is equal to or more than the threshold, the clutch is connected, and the braking force by the foot brake according to the stepping amount of the brake pedal, the braking force by the motor generator, and the braking force by the engine brake are set. By this, the hybrid vehicle Wherein the allowed speed.

  According to the hybrid vehicle of the present invention, the propeller shaft and the rotating shaft of the motor generator are connected via the reduction mechanism having the rotating shaft of the motor generator as the input shaft and the propeller shaft as the output shaft. Therefore, it is possible to improve the regeneration efficiency during high-speed running. Further, conversion from an existing non-hybrid vehicle to a hybrid vehicle can be facilitated.

  Further, when the vehicle speed of the hybrid vehicle is within a preset setting range and the transmission gear stage is a preset number of stages, when the brake pedal of the hybrid vehicle is depressed, the output value of the motor generator is reduced. The regenerative power generation is performed by the motor generator by controlling the output to a maximum value within a preset output range, and when the depression amount of the brake pedal is smaller than a preset threshold, the clutch is disengaged, and the brake pedal is depressed. When the amount is equal to or larger than the threshold value, the clutch is brought into the connected state, so that the motor generator having the maximum output value exerts the braking force, so that the braking performance of the hybrid vehicle can be improved. As a result, the load on the foundation brake can be reduced, and the life of the foundation brake can be improved.

  In the above configuration, the control device may be configured to further actuate an auxiliary brake of the hybrid vehicle when an amount of depression of the brake pedal is equal to or greater than the threshold.

  According to this configuration, when the depression amount of the brake pedal is equal to or larger than the threshold, a larger braking force can be obtained as compared with a case where the auxiliary brake does not operate. Further, since the number of times of operating the manual switch for operating the auxiliary brake can be reduced, driver fatigue can be reduced.

A method for controlling a hybrid vehicle according to the present invention that achieves the above object includes a hybrid system having a diesel engine and a motor generator, a transmission connected to the diesel engine via a clutch, and a differential that drives the transmission and wheels. And a propeller shaft connecting the propeller shaft and the rotating shaft of the motor generator, wherein the rotating shaft of the motor generator is an input shaft and the propeller shaft is an output shaft. Connected via a speed reduction mechanism, and when the vehicle speed of the hybrid vehicle is within a preset setting range and the gear stage of the transmission has a preset number of stages, the brake pedal of the hybrid vehicle When the brake pedal is depressed, the output value of the motor generator is controlled to a maximum value within a preset output range, regenerative power generation is performed by the motor generator, and the depression amount of the brake pedal is set in advance. If the threshold value is smaller than the threshold value, the clutch is disengaged , the hybrid vehicle is decelerated by a braking force by a foot brake according to an amount of depression of the brake pedal, and a braking force by the motor generator, and the brake pedal When the depression amount of the brake pedal is equal to or more than the threshold, the clutch is connected, and the braking force by the foot brake according to the depression amount of the brake pedal, the braking force by the motor generator, and the braking force by the engine brake are set. Decelerates the hybrid vehicle It is characterized in.

  According to the control method for a hybrid vehicle according to the present invention, the propeller shaft and the rotating shaft of the motor generator are connected via the reduction mechanism having the rotating shaft of the motor generator as the input shaft and the propeller shaft as the output shaft. Therefore, the regeneration efficiency during high-speed running can be improved. Further, conversion from an existing non-hybrid vehicle to a hybrid vehicle can be facilitated.

  Further, when the vehicle speed of the hybrid vehicle is within a preset setting range and the transmission gear stage is a preset number of stages, when the brake pedal of the hybrid vehicle is depressed, the output value of the motor generator is reduced. The regenerative power generation is performed by the motor generator by controlling the output to a maximum value within a preset output range, and when the depression amount of the brake pedal is smaller than a preset threshold, the clutch is disengaged, and the brake pedal is depressed. When the amount is equal to or larger than the threshold value, the clutch is brought into the connected state, so that the motor generator having the maximum output value exerts the braking force, so that the braking performance of the hybrid vehicle can be improved. As a result, the load on the foundation brake can be reduced, and the life of the foundation brake can be improved.

  In the above method, a configuration may be adopted in which, when the depression amount of the brake pedal is equal to or larger than the threshold value, the auxiliary brake of the hybrid vehicle is further operated.

  According to this method, when the depression amount of the brake pedal is equal to or larger than the threshold value, a larger braking force can be obtained as compared with the case where the auxiliary brake does not operate. Further, since the number of times of operating the manual switch for operating the auxiliary brake can be reduced, driver fatigue can be reduced.

  ADVANTAGE OF THE INVENTION According to this invention, the regenerative efficiency at the time of high speed driving | running | working can be improved compared with the past, conversion from an existing non-hybrid vehicle to a hybrid vehicle is easy, and the life of a foundation brake can be improved.

1 is a configuration diagram of a hybrid vehicle according to an embodiment of the present invention. 5 is a flowchart illustrating an example of a control process of a control device for a hybrid vehicle.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a configuration diagram of a hybrid vehicle according to an embodiment of the present invention. This hybrid vehicle (hereinafter, referred to as “HEV”) is a large vehicle such as a bus or a truck, and includes a hybrid system having a diesel engine 10 and a motor generator 33 that are combined and controlled according to the driving state of the vehicle. .

  The HEV includes a fluid coupling 14, a wet multi-plate clutch 15, a transmission 20, a propeller shaft 25, a differential 26, a driving wheel 27, a speed reduction mechanism 30, an inverter 34, and a battery 35. The HEV includes an accelerator pedal 152 and a brake pedal 151. The HEV includes an accelerator opening sensor 92, a brake pedal opening sensor 93, a shift sensor 140, and a vehicle speed sensor 91 as sensors. Further, the HEV includes a control device 80.

In the diesel engine 10, the crankshaft 13 is driven to rotate by thermal energy generated by the combustion of fuel in a plurality of (in this example, six) cylinders 12 formed in the engine body 11. The rotational power of the crankshaft 13 is transmitted to the transmission 20 via the fluid coupling 14 and the wet multi-plate clutch 15. Note that a dry clutch may be used instead of the fluid coupling 14 and the wet multi-plate clutch 15.

  The transmission 20 uses an AMT that automatically shifts to a target shift speed determined based on the operating state of the HEV and map data set in advance. The transmission 20 includes a main transmission mechanism 21 capable of shifting input rotational power to a plurality of stages, and an auxiliary transmission mechanism capable of shifting rotational power transmitted from the main transmission mechanism 21 to two stages of a low speed stage and a high speed stage. 22.

  The rotational power shifted by the transmission 20 is transmitted to a differential 26 through a propeller shaft 25 connected to an output shaft 23 of the transmission 20, and is distributed as a driving force to a pair of driving wheels 27 each formed of a double tire.

  The motor generator 33 is electrically connected to a battery 35 through an inverter 34.

  The propeller shaft 25 and the rotation shaft 32 of the motor generator 33 are connected via a speed reduction mechanism 30. The speed reduction mechanism 30 uses the rotation shaft 32 of the motor generator 33 as an input shaft and uses the propeller shaft 25 as an output shaft. That is, in the speed reduction mechanism 30, the reduction ratio (Nm / Np), which is the ratio of the rotation speed Np of the propeller shaft 25 to the rotation speed Nm of the motor generator 33, is greater than 1.0. Note that this reduction ratio may be set to either fixed or variable.

  The brake pedal 151 and the accelerator pedal 152 are arranged at the feet of the driver's seat. The driver adjusts the speed of the HEV by adjusting the depression amount of the accelerator pedal 152. When the driver depresses the brake pedal 151, the foot brake applies a braking force to the driving wheels 27. The foot brake is an example of a foundation brake.

  The accelerator opening sensor 92 detects the opening of the accelerator pedal 152 (that is, the accelerator opening), and the brake pedal opening sensor 93 detects the opening of the brake pedal 151, and transmits the detection result to the control device 80. The shift sensor 140 detects the gear position (gear position) of the transmission 20, the vehicle speed sensor 91 detects the vehicle speed (km / h) of the HEV, and transmits the detection result to the control device 80.

  The control device 80 includes a CPU having a function as a control unit that controls the diesel engine 10, the wet multi-plate clutch 15, the transmission 20, the speed reduction mechanism 30, and the motor generator 33, and various information such as programs used for the operation of the CPU. It is constituted by an electronic control unit (Electric Control Unit; ECU) including a microcomputer having a ROM, a RAM, and the like having a function as a storage unit for storing.

  The control unit of the control device 80 assists at least a part of the driving force by the motor generator 33 when starting or accelerating the HEV, while performing regenerative power generation by the motor generator 33 during inertial running or braking. Then, the surplus kinetic energy is converted into electric power to charge the battery 35.

Further, the control unit of the control device 80 according to the present embodiment, when the vehicle speed is within a preset setting range and the gear stage of the transmission 20 has a preset stage number (set stage number), the brake pedal 151 When it is depressed, the output value of the motor generator 33 is controlled to the maximum value (ie, the maximum output value) within a preset output range, and regenerative power generation by the motor generator 33 is executed.

  Further, the control unit of the control device 80 sets the wet multi-plate clutch 15 to the disconnected state when the depression amount of the brake pedal 151 is smaller than a preset threshold value. By executing this control process, the regenerative power generation by the motor generator 33 having the maximum output value is executed with the wet multi-plate clutch 15 disconnected. On the other hand, when the depression amount of the brake pedal 151 is equal to or larger than the threshold, the control unit of the control device 80 sets the wet multi-plate clutch 15 to the connected state. Further, when the depression amount of the brake pedal 151 is equal to or more than the threshold, the control unit further activates the auxiliary brake of the HEV. By executing this control process, the regenerative power generation by the motor generator 33 having the maximum output value is executed while the wet-type multi-plate clutch 15 is connected, and the auxiliary brake is automatically operated.

  The details of the above-described control processing will be described below with reference to a flowchart. FIG. 2 is a flowchart illustrating an example of a control process of the control device 80. The control unit of the control device 80 repeatedly executes the flowchart of FIG. 2 at a predetermined cycle. It is assumed that the wet multi-plate clutch 15 is in the connected state at the first start of the flowchart of FIG.

  In step S <b> 10, the control unit sets the vehicle speed acquired based on the detection result of the vehicle speed sensor 91 within a set range previously stored in a storage unit (for example, a ROM) (that is, within a set range preset in the control device 80). It is determined whether or not there is, and whether the gear position of the transmission 20 acquired based on the detection result of the shift sensor 140 is the number of positions previously stored in the storage unit (that is, the number of steps previously set in the control device 80). It is determined whether or not the brake pedal 151 is depressed (ON) based on the detection result of the brake pedal opening sensor 93.

  If No is determined in step S10, the control unit ends the execution of the flowchart. When it is determined as Yes in step S10, the control unit sets the output value of the motor generator 33 to the maximum value in the output range stored in the storage unit in advance (that is, the maximum value in the output range preset in the control device 80). ), And the regenerative power generation by the motor generator 33 is executed (step S20).

  The specific value of the set range of the vehicle speed and the specific value of the set number of gear positions used in step S10 described above are not particularly limited, but in the present embodiment, as an example, When the brake pedal 151 is depressed while the HEV is traveling, it is considered preferable to set the output value of the motor generator 33 to the maximum output value and to exert the braking force by the motor generator 33 to the maximum. Use a combination of gears. The specific combination of the setting range of the vehicle speed and the setting number of the gear steps used in step S10 takes into account the size of the HEV body, the output of the diesel engine 10, the output of the motor generator 33, and the like. Then, an appropriate value is obtained in advance by performing experiments, simulations, and the like, and stored in the storage unit.

  In addition, as an example of the setting range of the vehicle speed used in step S10, for example, a range of a medium speed range or more (a vehicle speed range of 60 km / h or more as an example) is used as a vehicle speed, and a gear speed within this range is used. A gear position preset in the AMT according to each vehicle speed is used. That is, in this case, in the case where the vehicle speed is the middle speed or higher and the gear speed is the gear speed corresponding to this vehicle speed, when the brake pedal 151 is depressed, the motor having the maximum output value is determined in step S20. The regenerative power generation by the generator 33 is executed.

  After step S20, the control unit sets the depression amount of the brake pedal 151 acquired based on the detection result of the brake pedal opening sensor 93 to a threshold value stored in the storage unit (ROM) (that is, It is determined whether it is smaller than a (set threshold) (step S30).

  When the determination is Yes in step S30, that is, when the depression amount of the brake pedal 151 is smaller than the threshold, the control unit sets the wet multiple disc clutch 15 to the disconnected state in step S40, and sets the motor generator 33 having the maximum output value. (This is referred to as clutch disengagement regeneration). By executing the clutch regenerative operation, the HEV is decelerated by the braking force by the foot brake according to the depression amount of the brake pedal 151 and the braking force by the motor generator 33 having the maximum output value. After step S40, the control unit ends the execution of the flowchart.

  If No is determined in step S30, that is, if the depression amount of the brake pedal 151 is equal to or larger than the threshold, the control unit sets the wet multiple disc clutch 15 to the connected state in step S50, and sets the maximum output value by the motor generator 33. The regenerative power generation is executed, and the auxiliary brake is also operated (this is called clutch connection regeneration). By executing the clutch connection regeneration, the braking force by the foot brake according to the depression amount of the brake pedal 151, the braking force by the motor generator 33 having the maximum output value, and the wet multi-plate clutch 15 being connected. The HEV is effectively decelerated by the braking force generated by the engine brake and the braking force generated by the auxiliary brake. After step S50, the control unit ends the execution of the flowchart.

  The specific type of the auxiliary brake is not particularly limited, and for example, an exhaust brake, a retarder, or the like can be used. In the present embodiment, an exhaust brake is used as an example of the auxiliary brake. This auxiliary brake normally operates when an auxiliary brake switch (that is, a manual switch) arranged in the driver's seat is turned on. However, in the present embodiment, the control is performed even when No is determined in step S30. It is configured to operate automatically in response to an instruction from a unit.

  As described above, in the present embodiment, the auxiliary brake is operated in step S50, but the mode of the present embodiment is not limited to this. For example, in step S50, the auxiliary brake need not operate. In this case, in step S50, the regenerative power generation by the motor generator 33 having the maximum output value is executed with the wet multi-plate clutch 15 in the connected state.

  Although the specific value of the threshold used in step S30 is not particularly limited, in the present embodiment, for example, when the depression amount of the brake pedal 151 is equal to or more than this value, a required control value is set. The value of the depression amount of the brake pedal 151, which is considered to be better to use the engine brake to obtain the power, is used as the threshold value. The threshold value is determined in advance by performing experiments, simulations, and the like in consideration of the weight of the HEV and the like, and is stored in the storage unit of the control device 80 in advance.

  According to the HEV and the control method thereof according to the present embodiment described above, the propeller shaft 25 and the rotation shaft 32 of the motor generator 33 are used as the input shaft, and the propeller shaft 25 is used as the output shaft. Therefore, the regenerative braking torque of the motor generator 33 can be increased by the speed reduction mechanism 30 during inertial running during high-speed running, regardless of the gear position of the transmission 20. As a result, the regeneration efficiency during high-speed running can be improved. Further, according to this configuration, the HEV can be converted to the HEV simply by newly attaching the speed reduction mechanism 30 to the propeller shaft of the existing non-hybrid vehicle. Therefore, the layout change of the power train components can be made very small, so that the conversion from the existing non-hybrid vehicle to the HEV can be easily performed.

  Further, according to the present embodiment, when the vehicle speed is within the preset setting range and the gear stage of the transmission 20 has the preset number of stages, and the brake pedal 151 is depressed, When the regenerative power generation by the motor generator 33 having the output value is performed and the depression amount of the brake pedal 151 is smaller than a preset threshold value, the clutch (wet multi-plate clutch 15 or dry clutch) is disengaged (step S40), and the brake If the depression amount of the pedal 151 is equal to or greater than the threshold, the clutch is engaged (step S50). According to this configuration, the motor generator 33 having the maximum output value exerts a braking force, so that the braking performance of the HEV can be improved. As a result, the load on the foundation brake can be reduced, and the life of the foundation brake can be improved.

  Further, according to the present embodiment, when the amount of depression of the brake pedal 151 is smaller than the threshold value, the clutch enters the disconnected state (step S40), so that wear of the clutch can also be suppressed.

  Further, according to the present embodiment, when the depression amount of the brake pedal 151 is equal to or more than the threshold, the auxiliary brake also operates in step S50, so that a larger braking force is applied as compared with the case where the auxiliary brake does not operate in step S50. Obtainable. Further, according to this configuration, the number of times the manual switch for operating the auxiliary brake is operated can be reduced, so that driver fatigue can be reduced.

  Although the preferred embodiment of the present invention has been described above, the present invention is not limited to the specific embodiment, and various modifications and changes may be made within the scope of the present invention described in the appended claims. Is possible.

Reference Signs List 10 Diesel engine 15 Wet multi-plate clutch 20 Transmission 25 Propeller shaft 26 Differential 30 Reduction mechanism 32 Rotary shaft 33 Motor generator 80 Control device 151 Brake pedal

Claims (4)

A hybrid vehicle comprising: a hybrid system having a diesel engine and a motor generator; a transmission connected to the diesel engine via a clutch; a propeller shaft connecting the transmission and a differential for driving wheels; and a control device. At
The propeller shaft and the rotating shaft of the motor generator are connected via a reduction mechanism having the rotating shaft of the motor generator as an input shaft and the propeller shaft as an output shaft,
The control device includes:
When the vehicle speed of the hybrid vehicle is within a preset setting range, and the transmission has a predetermined number of gears, when the brake pedal of the hybrid vehicle is depressed, the output of the motor generator Control the value to the maximum value within the preset output range, execute regenerative power generation by the motor generator,
When the depression amount of the brake pedal is smaller than a preset threshold, the clutch is disengaged, and a braking force by a foot brake according to the depression amount of the brake pedal, and a braking force by the motor generator, Decelerating the hybrid vehicle,
When the depression amount of the brake pedal is equal to or more than the threshold value, the clutch is connected, and the braking force by the foot brake according to the depression amount of the brake pedal; the braking force by the motor generator; A hybrid vehicle, wherein the hybrid vehicle is decelerated by a braking force .   The hybrid vehicle according to claim 1, wherein the control device further activates an auxiliary brake of the hybrid vehicle when an amount of depression of the brake pedal is equal to or greater than the threshold. A hybrid vehicle control method comprising: a hybrid system having a diesel engine and a motor generator; a transmission connected to the diesel engine via a clutch; and a propeller shaft connecting the transmission and a differential driving wheels. ,
The propeller shaft and the rotating shaft of the motor generator are connected via a reduction mechanism having the rotating shaft of the motor generator as an input shaft and the propeller shaft as an output shaft,
When the vehicle speed of the hybrid vehicle is within a preset setting range, and the transmission has a predetermined number of gears, when the brake pedal of the hybrid vehicle is depressed, the output of the motor generator Control the value to the maximum value within the preset output range, execute regenerative power generation by the motor generator,
When the depression amount of the brake pedal is smaller than a preset threshold, the clutch is disengaged, and a braking force by a foot brake according to the depression amount of the brake pedal, and a braking force by the motor generator, Decelerating the hybrid vehicle,
When the depression amount of the brake pedal is equal to or more than the threshold value, the clutch is connected, and the braking force by the foot brake according to the depression amount of the brake pedal; the braking force by the motor generator; A method for controlling a hybrid vehicle , wherein the hybrid vehicle is decelerated by a braking force .   4. The hybrid vehicle control method according to claim 3, further comprising activating an auxiliary brake of the hybrid vehicle when the depression amount of the brake pedal is equal to or greater than the threshold.

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