JP2016175502A - Hybrid vehicle and control method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hybrid vehicle and a control method therefor such that while regeneration efficiency in a high speed travel is improved as compared with the conventional art, a fuel consumption is reduced so as to improve fuel economy without stopping a steering assist in an auto-cruising mode and while keeping a charged state of a battery within a proper range.SOLUTION: A hybrid vehicle comprises a speed reduction mechanism 30 which connects a propeller shaft 25 to a rotary shaft 32 of a motor generator 33 and a driving shaft 46 of a second power steering pump 45 respectively, and a switching device which switches a supply source for a power steering fluid to a steering unit 53 to the second power steering pump 45, and a controller 80 is configured to perform control to transmit driving force to the propeller shaft 25 via the speed reduction mechanism 30 by driving and rotating a motor generator 33 when a clutch 15 is placed in a disconnected state during an engine travel and a transmission 20 is placed in an automatic speed change mode for a travel on a steep uphill road L1.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a hybrid vehicle and a control method therefor, and more specifically, while improving the regeneration efficiency during high-speed driving as compared with the conventional vehicle, the charge state of the battery is appropriately adjusted without stopping the steering assist in the auto-cruise mode. The present invention relates to a hybrid vehicle that reduces fuel consumption and improves fuel efficiency while maintaining the range, and a control method thereof.

  In recent years, a hybrid vehicle (hereinafter referred to as “HEV”) including a hybrid system having an engine and a motor generator that are controlled in combination according to the driving state of the vehicle has attracted attention from the viewpoint of improving fuel efficiency and environmental measures. Yes. In the HEV, when the vehicle is accelerated or started, the driving force is assisted by the motor generator, while regenerative power generation is performed by the motor generator during inertia traveling or braking (see, for example, Patent Document 1).

  In such a so-called parallel HEV, the motor generator is normally connected to the drive system of the vehicle from the engine side of the transmission for shifting the rotational power of the engine. For this reason, when the HEV is traveling at high speed (for example, 50 to 90 km / h), the transmission is shifted to a high speed, so that the regenerative braking torque in the motor generator is reduced and the power generation is increased. There is a problem that it is difficult to improve the efficiency of regenerative power generation because it is out of the efficiency point.

  Further, since it is necessary to change the layout of the powertrain components of the existing vehicle in order to arrange the motor generator, there is a problem that it is not easy to convert the existing vehicle to HEV.

  In order to solve such a problem, the inventor uses a propeller shaft of a vehicle and a rotation shaft of a motor generator via a reduction mechanism having the rotation shaft of the motor generator as an input shaft and the propeller shaft as an output shaft. Invented to connect.

  Furthermore, the inventor focused on the fuel consumption in the auto cruise mode in order to improve the fuel efficiency of the newly devised HEV, and more specifically to improve the fuel efficiency of large vehicles such as HEV buses and trucks. .

  In the auto-cruise mode, based on the map information including the gradient and distance of the travel path to be traveled and the HEV vehicle weight, the engine travels with the driving force of the engine, and the assist with the driving force of both the engine and the motor generator. The vehicle speed is maintained at the target speed by appropriately selecting traveling, motor traveling that travels with the driving force of the motor generator, and inertia traveling that does not apply the driving force of the engine and the motor generator.

  However, in large vehicles such as buses and trucks, hydraulic steering units are used as steering units (power steering) to assist the driver's steering from the viewpoint of output, steering performance, and reliability. During this time, it is necessary to always supply power steering fluid to the hydraulic steering unit from a power steering pump that is driven by transmission of the driving force of the engine. Therefore, there is a problem in that the fuel consumption cannot be reduced because the engine cannot be stopped during the motor running or the inertia running.

Further, when traveling on an uphill with a steep slope in the auto-cruise mode, it is necessary to downshift the transmission gear stage in order to maintain the vehicle speed at the target speed. However, if the rotational power transmitted from the engine to the transmission is cut off by the clutch mechanism during the downshift, the driving force will be released during HEV running, and the vehicle speed will drop, and the vehicle speed will be the target. There was also the problem of increased fuel consumption to maintain speed.

  On the other hand, when driving on an uphill with a steep slope in auto cruise mode, the motor generator is rotated and assisted by the electric power charged in the battery to maintain the transmission gear stage without downshifting. Can do.

  However, if the mileage of a steep uphill slope is long, maintaining such assist travel will result in a low battery charge (SOC) and assist before climbing the steep uphill. There was also a problem that the use of traveling could not be used, and the fuel consumption worsened.

JP 2002-238105 A

  The object of the present invention is to improve the regenerative efficiency during high-speed driving than before, and to reduce the fuel consumption without stopping the steering assist in the auto-cruise mode and maintaining the battery charge state within an appropriate range. It is another object of the present invention to provide a hybrid vehicle that can improve fuel efficiency and a control method thereof.

  The hybrid vehicle of the present invention that achieves the above object is a propeller shaft that connects a transmission that is connected to a diesel engine via a clutch and a differential that drives a drive wheel, and is electrically connected to the diesel engine and a battery. A hybrid system having a motor generator, a first power steering pump connected to the diesel engine, a steering unit for assisting steering by using a power steering fluid supplied from the first power steering pump, and a gradient of a traveling path In a hybrid vehicle comprising a gradient acquisition device that acquires vehicle weight, a vehicle weight estimation device that estimates vehicle weight, a vehicle speed acquisition device that acquires vehicle speed, and a control device, the propeller shaft and the rotation shaft of the motor generator are , The mode A speed reduction mechanism that connects the generator rotation axis as an input shaft and the propeller shaft as an output shaft, a second power steering pump that is connected to the propeller shaft via the speed reduction mechanism, and the stoppage of the diesel engine A switching device that switches the power supply source of the power steering fluid supplied to the steering unit from the first power steering pump to the second power steering pump when the first power steering pump is stopped. When an auto-cruise mode is set to maintain the vehicle speed within a preset target speed range, inertial traveling that does not transmit the driving force of the diesel engine and the motor generator to the propeller shaft is applied to the gradient and the vehicle weight. The clutch is disengaged during the coasting In addition to performing control to stop the diesel engine by stopping fuel injection, when traveling on a steep uphill road where the slope is equal to or higher than a preset steep slope, the clutch and the clutch The motor generator is selected when engine running is selected to run with a driving force transmitted to the propeller shaft via the transmission, and the transmission is automatically shifted with the clutch disengaged during the engine running. Is configured to perform a control for transmitting a driving force from the motor generator to the propeller shaft via the speed reduction mechanism.

  Further, the hybrid vehicle control method of the present invention that achieves the above object is an engine that travels with a driving force transmitted from a diesel engine to a propeller shaft via a clutch and a transmission when the auto-cruise mode is set. Driving, driving power of the diesel engine, and assist driving that travels with the driving force transmitted from the motor generator electrically connected to the battery to the propeller shaft via the speed reduction mechanism, and the driving force of the motor generator The vehicle speed is set in advance by selecting a motor travel that travels at a speed and an inertia travel that does not transmit the driving force of the diesel engine and the motor generator to the propeller shaft based on the gradient and the vehicle weight. And running automatically while maintaining If selected, the clutch is disengaged to stop the diesel engine, and instead of the first power steering pump stopped when the diesel engine is stopped, transmission is performed from the propeller shaft via the speed reduction mechanism. A hybrid vehicle control method for driving the second power steering pump with the rotational power thus generated to supply power steering fluid to the steering unit, when the vehicle travels on a steep uphill road where the slope is equal to or higher than a preset steep slope, When the engine running is selected and the clutch is disengaged while the engine is running and the transmission is automatically shifting, the motor generator is driven to rotate from the motor generator via the speed reduction mechanism. To transmit the driving force to the propeller shaft. It is a method to.

  According to the hybrid vehicle and its control method of the present invention, the regenerative efficiency during high-speed traveling can be improved by connecting the rotating shaft of the motor generator and the propeller shaft via the speed reduction mechanism.

  In addition, the second power steering pump is connected to the propeller shaft via a speed reduction mechanism, and the power steering fluid supply source when the driving of the first power steering pump is stopped is switched to the second power steering pump, thereby driving the first power steering pump. Even if the engine stops, the supply of power steering fluid to the steering unit is always maintained, so that it is possible to avoid stopping the steering assist.

  In addition, while coasting in the auto cruise mode, the clutch is disengaged and the fuel injection is stopped to stop the diesel engine and the idling stop state. Can be reduced.

  Furthermore, when driving on a steep steep slope, when engine driving is selected and the clutch is disengaged while the engine is running and the transmission is automatically shifting, the motor generator Since the driving force is transmitted to the propeller shaft, it is possible to avoid a decrease in the vehicle speed due to the driving force being lost during the shift of the transmission. Thereby, while being able to shorten climbing time, the fuel consumption for maintaining the reduced vehicle speed in the target speed range can be suppressed.

  In addition, when the engine is running on a steep steep climb, the rotation of the motor generator that consumes the electric power charged in the battery is limited to the automatic transmission of the transmission with the clutch disengaged. Therefore, compared with driving on a steep uphill road with assist driving, the rotation drive of unnecessary and unsteepened motor generators is reduced, and even if a steep uphill road continues for a long time, the state of charge of the battery is maintained within an appropriate range. can do.

In other words, when driving on a steep uphill road with a steep slope, by optimizing the opportunity to rotate the motor generator, while maintaining the charge state of the battery in the appropriate range, The driving force during downshifting of the gear stage of the transmission can be supplemented by the rotational drive of the motor generator, so that fuel consumption associated with a decrease in vehicle speed can be reduced and fuel efficiency can be improved.

It is a block diagram of the hybrid vehicle which consists of embodiment of this invention. It is a block diagram which shows the vehicle-mounted network and control signal line of FIG. It is a flowchart explaining the control method of the hybrid vehicle which consists of embodiment of this invention. It is explanatory drawing which illustrated the relationship with the vehicle speed, an engine torque, a motor generator torque, the charge condition of a battery, and an altitude at the time of driving | running | working on a steep climbing slope in an auto cruise mode. It is explanatory drawing which illustrated the relationship with the vehicle speed, an engine torque, a motor generator torque, the charge condition of a battery, and an altitude at the time of driving | running | working on a steep climbing slope in an auto cruise mode.

  Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 show a hybrid vehicle according to an embodiment of the present invention. In addition, the dashed-dotted line of FIG. 2 has shown the vehicle-mounted network and the control signal line.

  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 controlled in combination according to the driving state of the vehicle. Yes. The HEV also includes a power steering system having a steering unit 53 that assists the steering of the steering 54 using the power steering fluid 51. Further, the HEV is configured to execute the auto cruise mode when the auto cruise operation switch 81 is turned on by the driver in the control device 80.

  First, the HEV hybrid system will be described. In the diesel engine 10, the crankshaft 13 is rotationally driven by thermal energy generated by the combustion of fuel in a plurality (six in this example) of cylinders 12 formed in the engine body 11. The rotational power of the crankshaft 13 is transmitted to the transmission 20 through the fluid coupling 14 and the wet multi-plate clutch 15 (hereinafter referred to as the clutch 15). 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 gears to a target gear determined based on the HEV operating state and preset map data. The transmission 20 includes a main transmission mechanism 21 capable of shifting input rotational power in a plurality of stages, and a sub-transmission mechanism capable of shifting rotational power transmitted from the main transmission mechanism 21 into two stages, a low speed stage and a high speed stage. 22.

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

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

The diesel engine 10 and the motor generator 33 are controlled by a control device 80. Specifically, the diesel engine 10 uses the engine speed Ne detected by the speed sensor 86 and the accelerator pedal depression amount detected by the accelerator opening sensor 92 to inject fuel into the cylinder 12 and the injection timing. Is adjusted. Further, the motor generator 33 adjusts the frequency of the inverter 34 and the current value between the battery 35 and the motor generator 33 according to the state of charge (SOC) of the battery 35, and the motor generator 33 when the HEV starts or accelerates. While assisting at least a part of the driving force, regenerative power generation is performed by the motor generator 33 during inertial running or braking, and surplus kinetic energy is converted into electric power to charge the battery 35.

  The propeller shaft 25 and the rotating shaft 32 of the motor generator 33 are connected via a speed reduction mechanism 30. The speed reduction mechanism 30 uses the rotating shaft 32 of the motor generator 33 as an input shaft and the propeller shaft 25 as an output shaft. That is, in the speed reduction mechanism 30, the speed 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.

  By providing the speed reduction mechanism 30, the regenerative braking torque of the motor generator 33 can be increased by the speed reduction mechanism 30 regardless of the gear stage of the transmission 20 during inertia traveling during high speed travel, thereby improving the regenerative efficiency. can do.

  In addition, since the speed reduction mechanism 30 is only newly attached to the propeller shaft 25 of the vehicle, and the layout of the powertrain component can be changed very little, the conversion from the existing vehicle can be performed more easily than before. .

  Next, the HEV power soaring system will be described. In this power steering system, the drive shaft 41 of the first power steering pump 40 is connected to the crankshaft 13 of the diesel engine 10 via a V-belt 42 or a gear, and the first power steering pump 40 driven by the diesel engine 10. However, the power steering fluid 44 is pumped to the first hydraulic circuit 43. The steering unit 53 assists the steering of the steering 54 using the supplied power steering fluid 51. Note that since the HEV of this embodiment is a large vehicle, a hydraulic steering unit including a hydraulic power cylinder having a large output and excellent steering performance and reliability is used as the steering unit 53.

  The second power steering pump 45 is connected to the propeller shaft 25 via the speed reduction mechanism 30. A double check valve 49 for switching the power supply source of the power steering fluid 51 from the first power steering pump 40 to the second power steering pump 45, various hydraulic circuits (first hydraulic circuit 43, second hydraulic circuit 47 and main hydraulic circuit 50), and When the first power steering pump 40 is stopped by the switching device including the accumulator 52 as the diesel engine 10 is stopped, the power source fluid 51 supplied to the steering unit 53 is supplied from the first power steering pump 40 to the first power steering pump 40. It is switched to the 2 power steering pump 45.

  The first hydraulic circuit 43 communicates the first power steering pump 40 and the double check valve 49. The second hydraulic circuit 47 communicates the second power steering pump 45 and the double check valve 49. It should be noted that the upstream end portion of the first hydraulic circuit 43 upstream of the first power steering pump 40 and the upstream end portion of the second hydraulic circuit 47 upstream of the second power steering pump 45 store the power steering fluids 44 and 48. Not connected to reservoir tank. The main hydraulic circuit 50 communicates the double check valve 49 and the steering unit 53. Further, the middle of the passage of the main hydraulic circuit 50 is branched and connected to the accumulator 52.

  The drive shaft 46 of the second power steering pump 45 is connected to the propeller shaft 25 via the speed reduction mechanism 30. Specifically, the propeller shaft 25 of the speed reduction mechanism 30 of the second power steering pump 45 and the motor generator 33 are connected. The first power transmission path 104 is connected to the propeller shaft 25 via a second power transmission path 105 arranged separately. In addition, the 1st power transmission path 104 and the 2nd power transmission path 105 can illustrate a gear mechanism, a belt mechanism, and a chain mechanism. If the second power transmission path 105 is configured to be connectable to the propeller shaft 25, the connection with the propeller shaft 25 can be released when the second power steering pump 45 is not driven, and the drive loss can be reduced accordingly.

  The double check valve 49 preferentially guides the higher one of the power steering fluids 44 and 48 supplied from the first power steering pump 40 and the second power steering pump 45 to the steering unit 53 via the main hydraulic circuit 50. It is a valve. Therefore, it is preferable that the set discharge pressure of the power steering fluid 48 of the second power steering pump 45 is set to be smaller than the setting discharge pressure of the power steering fluid 44 of the first power steering pump 40. Specifically, the second power steering pump 45 is provided with a relief valve. By adjusting the relief valve, the set discharge pressure of the second power steering pump 45 is smaller than the set discharge pressure of the first power steering pump 40. The value has been adjusted.

  The accumulator 52 accumulates the power steering fluid 51 (= 44, 48) supplied from the first power steering pump 40 and the second power steering pump 45 via the double check valve 49, and the supply source of the power steering fluid 51 is the double check valve 49. The accumulated power steering fluid 51 is supplied to the steering unit 53. Since this accumulator 52 can suppress a large fluctuation in the pressure of the power steering fluid 51 supplied to the steering unit 53, it is possible to avoid a deterioration in drivability.

  In this way, the second power steering pump 45 is connected to the propeller shaft 25 via the speed reduction mechanism 30, and the supply source of the power steering fluid 51 is switched from the first power steering pump 40 to the second power steering pump 45 by the switching device. Even when the power steering fluid 44 is not supplied from the first power steering pump 40 during traveling, the power steering fluid 48 pumped from the second power steering pump 45 driven by the rotational power of the propeller shaft 25 via the speed reduction mechanism 30 is converted into the steering unit. 53 can be supplied. Thereby, even if the diesel engine 10 is stopped during traveling, it is possible to avoid stopping the steering assist of the steering 54 during traveling.

  When the power steering fluid 44 is not supplied from the first power steering pump 40 during traveling, for example, when the diesel engine 10 stops, the first power steering pump 40 fails or the first hydraulic circuit 43 is damaged. A case where the vehicle falls into a situation and a case where the HEV travels only by the driving force of the motor generator 33 can be exemplified.

  Next, the auto cruise mode will be described. This auto-cruise mode is used especially when driving on a highway, and the program stored in the control device 80 automatically runs HEV when the auto-cruise operation switch 81 is turned on by the driver. It is a mode that runs on the street.

Specifically, when the auto-cruise operation switch 81 is turned on, the control device 80 performs map information and vehicle weight acquired by the map information acquisition device 82 for engine travel, assist travel, motor travel, and inertia travel. This mode is a mode in which HEV is automatically driven while being selected in a timely manner based on the vehicle weight M estimated by the estimation device 83 and maintaining the vehicle speed V acquired by the wheel speed sensor 84 within a preset target speed range.

  During the auto-cruise mode, if the accelerator pedal depression is detected by the accelerator opening sensor 92, the acceleration can be accelerated by the driving force from the diesel engine 10. When the brake pedal opening sensor 93 detects the depression of the brake pedal, the depression of a clutch pedal (not shown), or the release of the auto cruise operation switch 81 is released, the auto cruise mode is released. The

  The target speed range is a range between the upper limit speed vb and the lower limit speed vc with reference to the target speed va. The target speed va, the upper limit speed vb, and the lower limit speed vc can be set to arbitrary values by the driver. For example, the target speed va is set to 70 km / h or more and 90 km / h or less, and the upper limit speed vb is the target speed vb. The speed va is set to 0 km / h or higher and +10 km / h or lower, and the lower limit speed vc is set to -10 km / h or higher and 0 km / h or lower to the target speed va.

  The map information acquisition device 82 communicates with a satellite positioning system (GPS) connected to the control device 80 to acquire the current position of the HEV, and with a server storing 3D road data. It comprises means for acquiring three-dimensional road data including the slope θ and the travel distance s of the travel road, and means for extracting the slope θ and the travel distance s of the travel path from which the HEV will travel. As described above, a device that obtains a gradient θ for each traveling distance s by dividing a traveling distance s of 500 km or less into a traveling distance s every 500 m, and a device that obtains a traveling distance s for each gradient θ. It can be illustrated.

  The map information acquisition device 82 is not particularly limited as long as it has a function capable of acquiring at least the gradient θ and the travel distance s of the travel path. For example, the map information acquisition device 82 is stored in a drive recorder. An example of obtaining the gradient θ and the travel distance s of the travel path from the obtained three-dimensional road data is also possible. Further, the gradient θ may be calculated based on values acquired by the wheel speed sensor 84 and the acceleration sensor (G sensor) 85.

  The vehicle weight estimation device 83 is stored in the control device 80 and is transmitted to the drive wheel 27, specifically, a program for estimating the vehicle weight M when the control device 80 performs motor travel at the time of starting acceleration. Assuming that the driving force Fm is equal to the running resistance R, the motor rotation sensor 36 that obtains the output torque Tm of the motor generator 33 acquired by the inverter 34 and the rotation speed of the motor generator 33 in the motor running at the time of start acceleration. A program for estimating the vehicle weight M can be exemplified based on the acquired vehicle acceleration (hereinafter referred to as acceleration) a.

  The specific configuration of the vehicle weight estimation device 83 is not particularly limited as long as it has a function capable of estimating the vehicle weight M of HEV. However, the output torque Tm and acceleration at the time of starting acceleration by motor traveling are not limited. If the vehicle weight M is estimated based on a, the vehicle weight M can be estimated even when the vehicle speed V is low (speed of 30 km / h or less), and the rolling resistance Rr and air resistance of the running resistance R are estimated. Since each of Rd and the climbing resistance Rs can be disabled and the variables can be reduced, the vehicle weight M can be estimated more accurately and simply. In addition, the time of starting acceleration by motor running includes the time of HEV reverse.

  The control method in the auto cruise mode will be described below as a function of the control device 80. First, when the auto cruise operation switch 81 is turned on by the driver while the HEV is running, the control device 80 maintains the vehicle speed V within the target speed range based on the map information and the estimated vehicle weight M. Any one of engine running, assist running, motor running, and inertia running is selected as appropriate.

  The engine travels the HEV by the driving force Fe transmitted from the diesel engine 10 to the propeller shaft 25 via the clutch 15 and the transmission 20. In the assist travel, the HEV travels with both the driving force Fe from the diesel engine 10 and the driving force Fm transmitted from the motor generator 33 to the propeller shaft 25 via the speed reduction mechanism 30. In the motor travel, the HEV is traveled by the driving force Fm from the motor generator 33 with the clutch 15 disengaged. In inertial running, the HEV is run without transmitting the driving force of the diesel engine 10 and the motor generator 33 to the propeller shaft 25.

  Further, the control device 80 controls the clutch 15 to be disengaged and stop the fuel injection to stop the diesel engine 10 during coasting, and maintains the idling stop state during coasting. doing.

  As described above, even if the first power steering pump 40 is stopped when the diesel engine 10 is stopped, the power steering fluid 51 is constantly supplied from the second power steering pump 45 connected to the propeller shaft 25 to the steering unit 53. During the HEV traveling, the diesel engine 10 can be stopped without stopping the steering assist. Therefore, the fuel consumption during inertia traveling can be reduced by setting the clutch 15 to the disconnected state and stopping the diesel engine 10 by stopping the fuel injection during inertia traveling.

  Further, since the diesel engine 10 is stopped during coasting, the exhaust gas 71 from the exhaust valve 70 can be reduced, so that the exhaust gas is disposed in the exhaust passage 73 and passes through the exhaust manifold 72 from the exhaust valve 70. Thus, it is possible to suppress a reduction in the purification capacity of the exhaust gas purification device 75 that purifies the exhaust gas 71 that has driven the turbine 74. As a result, when the purification capacity of the exhaust gas purification device 75 is lowered, the fuel that does not contribute to the driving force of the HEV is injected to increase the temperature of the exhaust gas 71 to recover the purification capacity of the exhaust gas purification device 75. Since the opportunity for regeneration is reduced, the fuel consumption required for the regeneration can also be reduced. As the exhaust gas purification device 75, for example, a collection device that collects particulate matter in the exhaust gas 71 can be exemplified, and accumulation of particulate matter on the collection device is suppressed during motor running and inertia running. Therefore, fuel consumption necessary for regeneration of the collection device can be suppressed.

  In addition, the clutch 15 is disengaged during inertia traveling and the diesel engine 10 is stopped by stopping fuel injection, so that the rotational power of the propeller shaft 25 is reduced by the rotational drag of the diesel engine 10. Since this can also be avoided, energy loss during motor running and inertia running can be reduced to further improve fuel efficiency.

  In addition, the control device 80 may perform control to stop the diesel engine 10 by stopping the fuel injection while disengaging the clutch 15 while the motor is running.

  As described above, since the motor travel is stopped as well as the inertia travel, the fuel consumption during the motor travel can be reduced and the reduction in the purification capacity of the exhaust gas purification device 75 can be suppressed. Fuel consumption can be improved.

  In such an HEV, the control device 80 selects engine travel when traveling on the steep climb slope L3 having a gradient θ3 equal to or higher than the preset steep gradient θa, and also disengages the clutch 15 during the engine travel. When the transmission 20 is automatically shifting, the motor generator 33 is rotationally driven, and control is performed to transmit driving force from the motor generator 33 to the propeller shaft 25 via the speed reduction mechanism 30.

  Examples of the gradient acquisition device include the map information acquisition device 82 and the G sensor 85 described above.

  The steep uphill road L3 is an uphill with a steep slope θ3, and the gear stage of the transmission 20 must be downshifted only by the driving force of the diesel engine 10 due to the running resistance including the force in the reverse direction due to the gravitational acceleration applied to the vehicle body. In other words, the vehicle speed V cannot be maintained within the target speed range, that is, the vehicle speed V can be maintained at the target speed va or higher or the lower limit speed vc or higher when the assist travel is performed in at least a part of the section. As such a steep climbing road L3, for example, when the HEV vehicle weight M is 25 t, a climbing road with a gradient θ3 of 3% or more and a distance s3 of 500 m or more can be exemplified.

  Switching from engine running to assist running when the transmission 20 is automatically shifting is controlled by a stroke sensor 128 as an advancing / retreating width obtaining device for obtaining the advancing / retreating width Δd1 of the clutch actuator 120 for connecting / disconnecting the clutch 15. The device 80 controls to rotate the motor generator 33 when the advance / retreat width Δd1 becomes the cut width Δda that makes the clutch 15 disengaged, while the advance / retreat width Δd1 brings the clutch 15 into the engaged state. When the connection width Δdb is reached, it is desirable to perform control to stop the rotation drive of the motor generator 33.

  The clutch actuator 120 can be exemplified by a pneumatic actuator that is generated by the air compressor 61 connected to the diesel engine 10 and moves forward and backward using the compressed air 65 accumulated in the air tank 64. The air tank 64 and the clutch actuator 120 can be exemplified. The flow rate of the compressed air 65 supplied by the clutch proportional control valve 121 provided in the second pneumatic pipe line 66 connecting the two is adjusted.

  The cutting width Δda and the connection width Δdb are obtained in advance by experiments and tests, stored in the control device 80, and preferably set to the advance / retreat width of the clutch actuator 120 in a state where the clutch 15 slips. For example, when the clutch 15 is in the coupled state of about 1/3, when the clutch 15 slips, the cut width Δda and the connection width Δdb may be set to the same value.

  A control method in the HEV auto-cruise mode will be described below as a function of the control device 80 based on the flowchart of FIG. It is assumed that this control method is performed while the vehicle is running on a steep uphill road L3 having a slope θ3 equal to or higher than the steep slope θa when the driver turns on the auto-cruise operation switch 81 while the HEV is running.

  First, in step S10, the control device 80 determines a downshift of the gear stage of the transmission 20 in order to maintain the vehicle speed V in the target speed range, transmits a shift command, and proceeds to step S20. In this step S10, for example, a shift command is transmitted based on shift map data in which a downshift line or an upshift line based on the vehicle speed V and the engine speed Ne is set.

  Next, in step S20, the control device 80 sends a disconnection control signal Ic2 to the clutch proportional control valve 121, disengages the clutch 15, and proceeds to step S30. In this step S20, the clutch proportional control valve 121 is closed by the cutting control signal Ic2, the compressed air 65 is discharged from the inside of the clutch actuator 120, and the clutch 15 is connected as the clutch actuator 120 moves backward. Will be disconnected.

  Next, in step S30, the control device 80 determines whether or not the advance / retreat width Δd1 of the clutch actuator 120 acquired by the stroke sensor 128 is equal to or smaller than a preset cutting width Δda. If the advance / retreat width Δd1 exceeds the cutting width Δda in step S20, the process returns to step S20. If the advance / retreat width Δd1 is equal to or less than the cutting width Δda, the process proceeds to step S40.

  Next, in step S40, the control device 80 rotationally drives the motor generator 33 with the electric power charged in the battery 35, and proceeds to step S50. By this step S40, the rotational power of the motor generator 33 is transmitted to the propeller shaft 25 via the speed reduction mechanism 30.

  Next, in step S50, the control device 80 shifts the transmission 20 using a transmission actuator (not shown), and the process proceeds to step S60. Next, in step S60, the control device 80 sends a connection control signal Ic1 to the clutch proportional control valve 121 to place the clutch 15 in the engaged state, and the process proceeds to step S70. In this step S60, compressed air 65 having a flow rate proportional to the connection control signal Ic1 sent from the clutch proportional control valve 121 is supplied to the clutch actuator 120, and the unit is supplied by the compressed air 65 supplied to the clutch actuator 120. The clutch 15 moves from the disengaged state to the connected state by advancing and retreating with the expansion / contraction width Δdc per time.

  Next, in step S70, the control device 80 determines whether or not the advance / retreat width Δd1 of the clutch actuator 120 acquired by the stroke sensor 128 is equal to or larger than a preset cutting width Δda. If the advance / retreat width Δd1 is less than the cutting width Δda in step S70, the process returns to step S60. If the advance / retreat width Δd1 is greater than or equal to the cutting width Δda, the process proceeds to step S80.

  Next, in step S80, the control device 80 stops the rotational drive of the motor generator 33 and returns to the start.

  FIG. 4 shows an example of the relationship among the vehicle speed V, the output torque Te of the diesel engine 10, the output torque Tm of the motor generator 33, the state of charge Ce of the battery 35, and the altitude H on the steep climb road L3.

  Steps S10 to S40 are performed at point A when the vehicle is traveling on the steeply uphill road L3 by engine traveling. Here, the clutch 15 for downshifting the gear stage of the transmission 20 is disengaged, and the rotational power of the motor generator 33 is transmitted to the propeller shaft 25 via the speed reduction mechanism 30. Next, step S50 is performed between the point A and the point B. From the point A to the point B, the driving force from the diesel engine 10 is not transmitted and the vehicle travels only with the driving force of the motor generator 33. . Next, steps S60 to S80 are performed at point B. Here, the clutch 15 is connected, and the motor generator 33 is stopped.

  Similarly, the rotational power of the motor generator 33 is transmitted to the propeller shaft 25 via the speed reduction mechanism 30 while the transmission 20 is shifting at the points C and D, and the points E and F.

  Since such control is performed, when traveling on the steep uphill road L3 having the steep slope θa, engine traveling is selected, the clutch 15 is disengaged during the engine traveling, and the transmission 20 is automatically shifted. When the vehicle is running, the driving force of the motor generator 33 is transmitted to the propeller shaft 25 via the speed reduction mechanism 30 to avoid a decrease in the vehicle speed V due to the driving force being lost during the speed change of the transmission 20. . As a result, the climbing time can be shortened and the fuel consumption for maintaining the reduced vehicle speed V in the target speed range can be suppressed.

  In addition, when the engine is running on the steep uphill road L3 having the steep slope θa, the rotational drive of the motor generator 33 that consumes the electric power charged in the battery 35 is limited to the automatic transmission of the transmission 20. Compared with the case where the vehicle travels on the steep uphill road L3 by assist running, the rotational driving of the motor generator 33 that is unnecessary and abrupt is reduced, and even if the steep uphill road L3 continues for a long time, the charging state Ce of the battery 35 is changed. It can be maintained within an appropriate range.

  That is, when the vehicle travels on the steep ascending slope L3 where the gradient θ3 is steep, the opportunity of rotationally driving the motor generator 33 is made appropriate, and the charge state Ce of the battery 35 is maintained in an appropriate range, while the transmission 20 The driving force during the downshift of the gear stage can be supplemented by the rotational drive of the motor generator 33 to reduce the fuel consumption accompanying the decrease in the vehicle speed V and improve the fuel efficiency.

  In the HEV described above, when it is assumed that the control device 80 has performed the assist travel, the battery can be maintained when the vehicle speed V can be maintained at the target speed va or higher or the lower limit speed vc or greater and the assist travel has been performed. Control is performed to predict the steep climbing slope L3 where the charging state Ce of 35 is equal to or higher than the low charging state Cl set to the full discharging state (0%) or more and the half charging state (50%) or less. The uphill road L3 is preferably configured to perform control for selecting assist travel.

  As shown in FIG. 5, the control device 80 can maintain the vehicle speed V at the target speed va or higher when assisting the steep climbing slope L3 from the point C to the point D and perform the assist traveling. In this case, if it is predicted that the charging state Ce of the battery 35 will be equal to or higher than the low charging state Cl, the assist travel is selected from the point C to the point D. As a result, on the steep uphill road L3, the increase in the output of the diesel engine 10 is suppressed by assist traveling, the transmission 20 is traveled without downshifting, or the gear 20 is traveled one gear up, Since the fuel consumption can be suppressed by setting the engine speed Ne of the diesel engine 10 to the low rotation side, the fuel consumption can be further improved.

DESCRIPTION OF SYMBOLS 10 Diesel engine 15 Clutch 20 Transmission 25 Propeller shaft 26 Differential 27 Drive wheel 30 Deceleration mechanism 32 Rotation shaft 33 Motor generator 35 Battery 40 First power steering pump 45 Second power steering pump 49 Double check valve 53 Steering unit 80 Control device 81 Auto cruise operation Switch 82 Map information acquisition device 83 Vehicle weight estimation device 84 Wheel speed sensor L3 Steep climbing road

Claims (4)

A hybrid system having a propeller shaft that couples a transmission connected to a diesel engine via a clutch and a differential that drives a drive wheel, a hybrid system that has a motor generator electrically connected to the diesel engine and a battery, and the diesel engine A first power steering pump, a steering unit that assists steering using the power steering fluid supplied from the first power steering pump, a gradient acquisition device that acquires a gradient of a traveling path, and a vehicle weight are estimated In a hybrid vehicle including a vehicle weight estimation device, a vehicle speed acquisition device that acquires a vehicle speed, and a control device,
A reduction mechanism that connects the propeller shaft and the rotation axis of the motor generator with the rotation axis of the motor generator as an input shaft and the propeller shaft as an output shaft, and is coupled to the propeller shaft via the reduction mechanism. When the first power steering pump stops with the stop of the diesel engine, the power steering fluid supplied to the steering unit is supplied from the first power steering pump to the second power steering pump. A switching device for switching to a pump,
When the control device is set to an auto-cruise mode in which the vehicle speed is maintained within a preset target speed range, inertial running that does not transmit the driving force of the diesel engine and the motor generator to the propeller shaft is applied to the gradient. And when selecting based on the vehicle weight, in addition to performing the control to stop the diesel engine by stopping the fuel injection and stopping the clutch during the inertial running,
When traveling on a steeply uphill road where the gradient is equal to or higher than a preset steep slope, the engine traveling that travels with the driving force transmitted from the diesel engine to the propeller shaft via the clutch and the transmission is selected. When the transmission is automatically shifting with the clutch disengaged while the engine is running, the motor generator is driven to rotate, and the driving force is applied from the motor generator to the propeller shaft via the speed reduction mechanism. A hybrid vehicle characterized in that it is configured to perform control to transmit power. An advance / retreat width acquisition device for acquiring an advance / retreat width of an actuator for connecting and disconnecting the clutch;
The control device, when the advance / retreat width is a cutting width for disengaging the clutch, control to rotate the motor generator,
On the other hand, the hybrid vehicle according to claim 1, wherein when the advance / retreat width becomes a connection width that brings the clutch into a connected state, control is performed to stop rotation driving of the motor generator. When it is assumed that the control device performs an assist travel that travels with both the driving force of the diesel engine and the driving force transmitted from the motor generator to the propeller shaft via the speed reduction mechanism, the vehicle speed is It is possible to maintain the target speed over the target speed set in the target speed range, or over the lower limit speed of the target speed range, and assuming that the assist travel is performed, the state of charge of the battery is not less than the full discharge state, the half charge state Perform control to predict the steep climb slope that will be above the low charge state set below,
The hybrid vehicle according to claim 1, further comprising a control for selecting the assist travel on the predicted steeply uphill road. When the auto cruise mode is set, the engine travels with the driving force transmitted from the diesel engine to the propeller shaft via the clutch and transmission, and is electrically connected to the driving force and the battery of the diesel engine. Assist traveling that travels with both driving force transmitted from the motor generator to the propeller shaft via the speed reduction mechanism, motor traveling that travels with the driving force of the motor generator, and driving force of the diesel engine and the motor generator Inertia traveling that is not transmitted to the propeller shaft is selected on a timely basis based on the gradient and the vehicle weight, and the vehicle speed is maintained within a preset target speed range to automatically travel,
When the inertial running is selected, the clutch is disengaged to stop the diesel engine, and instead of the first power steering pump that is stopped when the diesel engine is stopped, the speed reduction mechanism is changed from the propeller shaft. A method for controlling a hybrid vehicle that drives a second power steering pump with rotational power transmitted via a power supply to supply power steering fluid to a steering unit,
When traveling on a steep uphill road where the gradient is equal to or higher than a preset steep slope, the engine traveling is selected, and the clutch is disengaged during the engine traveling and the transmission is automatically shifted. A method for controlling a hybrid vehicle, wherein the motor generator is rotationally driven and a driving force is transmitted from the motor generator to the propeller shaft via the speed reduction mechanism.