JP6547497B2 - Hybrid vehicle and control method thereof - Google Patents

Description

  The present invention relates to a hybrid vehicle and a control method thereof, and more specifically, while improving regeneration efficiency at high speed traveling than before, avoiding deterioration of a battery and avoiding output suppression of a motor generator to further improve fuel efficiency The present invention relates to an improved hybrid vehicle and a control method thereof.

  BACKGROUND ART In recent years, a hybrid vehicle (hereinafter referred to as "HEV") equipped with a hybrid system having an engine and a motor generator which are complexly controlled in accordance with the driving condition of the vehicle attracts attention from the viewpoint of fuel efficiency improvement and environmental measures. There is. In this HEV, at the time of acceleration or start of the vehicle, assist of the driving force by the motor generator is performed at the time of acceleration or start, while regenerative power generation is performed by the motor generator at the time of inertia traveling or braking.

  In such a so-called parallel HEV, the motor generator is normally connected from the engine side of the transmission that changes the rotational power of the engine to the drive system of the vehicle, that is, to the drive system of the vehicle via the transmission. Therefore, when the HEV is in an inertial traveling state during high-speed traveling (for example, 50 to 90 km / h), the transmission is shifted to the high-speed stage, so power is transmitted via the gear of this high-speed stage There is a problem that it is difficult to improve the efficiency of regenerative power generation because the regenerative braking torque in the motor generator becomes small and deviates from the point of high efficiency of power generation.

  Further, in this HEV, the layout of the powertrain components of the existing vehicle is required to be largely changed in order to arrange the motor generator, so that the HEV can not be easily converted to an existing vehicle. there were.

  In order to solve such a problem, the inventor uses a reduction mechanism in which the propeller shaft of the vehicle and the rotation shaft of the motor generator are input shafts while the rotation shaft of the motor generator is an input shaft and the propeller shaft is an output shaft. I devised to connect.

  The inventor also focused on the suppression of battery deterioration of a newly designed HEV, such as a bus or truck, and the improvement of fuel efficiency by avoiding the output suppression of the motor generator.

  Using a motor generator raises the temperature of the motor generator, inverter, and battery. Therefore, a hybrid vehicle is equipped with a cooling system that cools a water-cooled motor generator and inverter by driving an electric pump with electric power generated by an alternator connected to a diesel engine to circulate cooling water. .

  The output of the motor generator is set to be suppressed by the inverter when the temperature of the cooling water of the cooling system exceeds a preset upper limit value. For this purpose, the cooling system is set to a drive start temperature lower than the upper limit value, and is set to drive the electric pump when the temperature of the cooling water becomes equal to or higher than the drive start temperature. For example, the drive start temperature when the upper limit value is 60 ° C. can be, for example, about 50 ° C.

However, after using regenerative braking with a motor generator on a downhill road or after using assist with a motor generator on an uphill road, the temperature of the cooling water of the cooling system exceeds the upper limit, and the inverter outputs the motor generator output. There is a problem that the fuel consumption is deteriorated due to the insufficient assist of the motor generator or the reduction of the power generation amount due to the regeneration.

  On the other hand, if the drive start temperature is set to a lower temperature to avoid the suppression of the output of the motor generator, the power consumption of the electric pump increases, and the opportunity for power generation of the alternator increases and the fuel consumption deteriorates. was there.

  Furthermore, there is also a problem that the battery, which charges the electric power generated by the regeneration of the motor generator, is deteriorated when the charge state is maintained high.

JP 2002-238105 A

  An object of the present invention is a hybrid vehicle that can improve battery efficiency while avoiding deterioration of a battery and avoiding output suppression of a motor generator while improving regeneration efficiency when traveling at a higher speed than before. It is to provide the control method.

  A hybrid vehicle according to the present invention for achieving the above object comprises: a propeller shaft connecting a transmission connected to a diesel engine via a clutch device and a differential driving a wheel; and an inverter connected to the diesel engine and battery. Power generated by the alternator connected to the diesel engine when the temperature of the cooling water for cooling the motor-generator and the water-cooled motor-generator and the inverter reaches a preset drive start temperature. A cooling system that drives an electric pump driven by different powers to circulate cooling water, a map information acquisition device that acquires map information, a vehicle weight acquisition device that acquires vehicle weight, and a vehicle speed acquisition device that acquires vehicle speed And control equipment And connecting the rotating shaft of the motor generator and the propeller shaft via a reduction mechanism having the rotating shaft as an input shaft and the propeller shaft as an output shaft, and the control device being When the auto cruise mode for maintaining the vehicle speed in a preset target speed range is set, the presence or absence of a downhill road on which the vehicle speed increases is predicted based on the map information and the vehicle weight. On the downhill road, the clutch device is disengaged and the fuel injection is stopped to select the inertia running with the diesel engine stopped, and during the inertia running, the motor generator operates the regenerative brake to generate electric power to generate regenerative braking. To maintain the target speed range, the charging state of the battery at a midway position of the Before the generator becomes larger than the maximum charge state, and the clutch device is engaged while maintaining the stop of the diesel engine while the regenerative torque of the motor generator is reduced, and the alternator generates power, and the power is generated by the alternator. It is characterized in that the electric pump drives the electric pump to control the motor generator and the inverter to be cooled.

  Further, according to the control method of a hybrid vehicle of the present invention for achieving the above object, the driving force transmitted from the diesel engine to the propeller shaft via the clutch device and the transmission when the auto cruise mode is set, And either an engine travel, a motor travel, or an assist travel that travels with one or both of the driving powers transmitted to the propeller shaft from the motor generator connected to the battery via the inverter via the reduction mechanism. Map information and vehicle weight including at least a slope: either the clutch operation is disengaged and the diesel engine is stopped to transmit the driving power of the diesel engine and the motor generator not to the propeller shaft. On the basis of the A control method for a hybrid vehicle, wherein the hybrid vehicle is automatically traveled while maintaining the vehicle speed within a preset target speed range when the vehicle speed is increased based on the map information and the vehicle weight. In the case of predicting and predicting the downhill, the motor generator generates regenerative power during regenerative travel on the downhill, and maintains the vehicle speed in the target speed range when the vehicle speed is maintained in the target speed range. An alternator connected to the diesel engine with the clutch device connected while reducing the regenerative torque of the motor generator and maintaining the stop of the diesel engine before the state of charge of the battery becomes greater than the maximum charge state. Power generator, and the electric power generated by the alternator drives an electric pump to cool the Circulating the water, wherein the cooling the motor generator and said inverter water-cooled in that the cooling water.

  As for the state of charge of the battery, an appropriate operating range (SOC) is determined according to the type of the battery, and the maximum charging state as referred to herein means the upper limit of the operating range. Therefore, for example, when the state of charge of the battery is 0% for full discharge and 100% for full charge, the state of maximum charge is 70% or more and 90% or less.

  According to the hybrid vehicle and the control method thereof of the present invention, by connecting the rotating shaft of the motor generator and the propeller shaft via the speed reduction mechanism, it is possible to improve the regeneration efficiency at high speed traveling than before.

  In addition, when the regenerative brake is activated during inertia running with the diesel engine stopped on the downhill road to bring the vehicle speed into the target speed range, the battery is not fully charged at the halfway position of the downhill road. By squeezing the regenerative torque of the motor generator, it is possible to prevent the battery from being fully charged in the middle of the downhill.

  In addition, the clutch device is connected while maintaining the stop of the diesel engine, power generated by the alternator is generated by the power transmitted from the propeller shaft, the electric power is driven by the generated power, and the water-cooled motor generator is generated. And by cooling the inverter, it is possible to drive the electric pump with electric power generated by the alternator without consuming fuel and suppress fuel consumption, regardless of the temperature of the cooling water of the cooling system. Can cool the motor generator and inverter.

  As a result, it is possible to suppress the deterioration of the battery and to reduce the fuel consumption by the stopping of the diesel engine during coasting and the power generation of the alternator by the power transmitted from the propeller shaft. Can be maintained at a low level, so that the deterioration due to the temperature of the motor generator and inverter can be avoided, and furthermore, the output of the motor generator is prevented from being suppressed at the next driving time. Since the power and assist power can be secured to the maximum, the fuel consumption can be further improved.

Furthermore, during the inertia running with the diesel engine stopped on the downhill, even if the regenerative braking force of the regenerative brake decreases, the alternator is generated with the clutch device connected while maintaining the stop of the diesel engine. Therefore, since the braking force by the power generation of the alternator can be applied, the frequency of use of the foot brake when maintaining the vehicle speed in the target speed range can be reduced, and the life of the foot brake can be improved.

1 is a configuration diagram of a hybrid vehicle according to an embodiment of the present invention. It is a block diagram which shows the vehicle-mounted network of FIG. 1, and a control signal line. FIG. 5 is a flow chart for explaining a control method of a hybrid vehicle according to an embodiment of the present invention. FIG. 6 is an explanatory view exemplifying a relationship among a vehicle speed, an engine torque, a motor generator torque, a charge state of a battery, a temperature of cooling water of a cooling system, and an elevation when traveling on a downhill road in an auto cruise mode. FIG. 7 is a flow chart for explaining another example of the control method of the hybrid vehicle according to the embodiment of the present invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 and 2 show a hybrid vehicle according to an embodiment of the present invention. Although the alternator 17 and the electric pump 131 and the electric fan 132 of the cooling circuit 130 are not connected in FIG. 1, they are electrically connected by wiring (not shown) in practice. Moreover, 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 which are comprehensively controlled in accordance with the driving state of the vehicle. There is. In addition, this HEV is equipped with a cooling system for cooling a water-cooled motor generator 33 and an inverter 34. Furthermore, this HEV is configured such that the controller 80 executes the auto cruise mode when the auto cruise operation switch 81 is turned on by the driver.

  First, a hybrid system of HEV will be described. In the diesel engine 10, the crankshaft 13 is rotationally driven by the thermal energy generated by the combustion of fuel in the plurality of (six in this example) cylinders 12 formed in the engine main 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. A dry clutch may be used instead of the fluid coupling 14 and the wet multi-plate clutch 15.

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

  The rotational power transmitted 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 drive wheels 27 formed 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 controller 80. Specifically, in the diesel engine 10, the injection amount and injection timing of fuel to the cylinder 12 are based on the engine rotational speed Ne detected by the rotational speed sensor 86 and the depression amount of the accelerator pedal detected by the accelerator opening degree sensor 92. Is adjusted. In addition, 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, etc. While assisting at least a part of the driving force by this, during inertial traveling or braking, regenerative power generation is performed by the motor generator 33, surplus kinetic energy is converted into electric energy, and the battery 35 is charged.

  The propeller shaft 25 and the rotation shaft 32 of the motor generator 33 are connected via the 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 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 speed reduction ratio may be set to either fixed or variable.

  By providing the reduction mechanism 30, the regenerative braking torque of the motor generator 33 can be increased by the reduction mechanism 30 regardless of the gear position of the transmission 20 during inertial traveling during high-speed traveling, thus improving regeneration efficiency. can do.

  In addition, since only the decelerating mechanism 30 is newly attached to the propeller shaft 25 of the vehicle and the change of the layout of the powertrain components can be very small, conversion of the existing engine only from the vehicle to HEV is easier than before. It can be carried out.

  Subsequently, the power siding system of HEV 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 44 is pumped to the first hydraulic circuit 43. Then, the steering unit 53 assists the steering of the steering 54 by using the supplied power steering 51. Since the HEV of this embodiment is a large vehicle, a hydraulic steering unit provided with a hydraulic power cylinder having a large output and excellent in 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. Also, a double check valve 49 that switches the power source of the power steering 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), When the first power steering pump 40 is stopped by the switching device including the accumulator 52 when the diesel engine 10 is stopped, the power source of the power steering 51 supplied to the steering unit 53 is supplied from the first power steering pump 40. It has switched to 2 power steering pump 45.

  The first hydraulic circuit 43 communicates the first power steering pump 40 with the double check valve 49. The second hydraulic circuit 47 communicates the second power steering pump 45 with the double check valve 49. The end of the first hydraulic circuit 43 upstream of the first power steering pump 40 and the end of the second hydraulic circuit 47 upstream of the second power steering pump 45 store the power steerings 44, 48. It is connected to a reservoir tank (not shown). The main hydraulic circuit 50 communicates the double check valve 49 with the steering unit 53. Further, a branch 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 propeller shaft 25 is connected via a second power transmission path 105 provided separately from the first power transmission path 104. The first power transmission path 104 and the second power transmission path 105 can be exemplified by a gear mechanism, a belt mechanism, and a chain mechanism. Further, when the second power transmission path 105 is configured to be connectable to the propeller shaft 25, when the second power steering pump 45 is not driven, the connection with the propeller shaft 25 can be released, and the driving loss can be reduced accordingly.

  The double check valve 49 preferentially guides the higher pressure one of the power steering fluid 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, the set discharge pressure of the power steering 48 of the second power steering pump 45 is preferably set to be smaller than the set discharge pressure of the power steering 44 of the first power steering pump 40. Specifically, the second power steering pump 45 is provided with a relief valve (not shown), and by adjusting the relief valve, the setting discharge pressure of the second power steering pump 45 is the setting discharge of the first power steering pump 40. The pressure is adjusted to a smaller value.

  The accumulator 52 stores the power steering fluid 51 (= 44, 48) supplied from the first power steering pump 40 and the second power steering pump 45 and passed through the double check valve 49, and the power source of the power steering fluid 51 is the double check valve 49. When it is switched, the stored power steering 51 is supplied to the steering unit 53. Since the accumulator 52 can suppress large fluctuations in the pressure of the power steering 51 supplied to the steering unit 53, the deterioration of the drivability can be avoided.

  Thus, by connecting the second power steering pump 45 to the propeller shaft 25 via the reduction gear mechanism 30 and switching the supply source of the power steering fluid 51 from the first power steering pump 40 to the second power steering pump 45 by the switching device. Even when the power steering wheel 44 is not supplied from the first power steering pump 40 during traveling, the steering wheel unit 48 is powered by the second power steering pump 45 driven by the rotational power of the propeller shaft 25 via the reduction mechanism 30. 53 can be supplied. As a result, even if the diesel engine 10 is stopped during traveling, it is possible to avoid that the steering assist of the steering 54 during traveling is stopped.

  When the power steering 44 is not supplied from the first power steering pump 40 during traveling, for example, when the diesel engine 10 is stopped, the first power steering pump 40 is broken or the first hydraulic circuit 43 is broken. In the case where the situation occurs, the case where the HEV travels with only the driving force of the motor generator 33 can be exemplified.

  Subsequently, the cooling system will be described. In this cooling system, the alternator 17 is connected to the crankshaft 13 of the diesel engine 10 via a V-belt 42 or a gear, and the electric power generated by the alternator 17 driven by the diesel engine 10 is direct or indirect. It is supplied to the electric pump 131 and the electric fan 132 of the cooling circuit 130. In the cooling circuit 130, the cooling water 133 is circulated by the electric pump 131 by the electric pump 131, the radiator 134, the water-cooled inverter 34, the water-cooled motor generator 33, the catch tank 135, and the electric pump 131 in this order. The inverter 34 is being cooled. Further, the cooling air cools the battery 35 and the radiator 134 disposed in the unit box 136 by the electric fan 132.

  In the cooling circuit 130, a temperature sensor 137 for detecting the temperature T1 of the cooling water 133 is disposed downstream of the radiator 134. In the cooling system, the temperature T1 of the cooling water 133 detected by the temperature sensor 137 is The electric pump 131 and the electric fan 132 are configured to be driven when the set driving start temperature Ta or more is reached. The drive start temperature Ta is lower than the upper limit temperature Tb at which the deterioration of the permanent magnet of the motor generator 33 is concerned, and the drive of the electric pump 131 does not occur frequently to suppress the deterioration of the fuel efficiency due to the increase of the power consumption. For example, when the upper limit temperature Tb is set to 60 ° C. to 70 ° C., the drive start temperature Ta is set to 50 ° C. to 60 ° C.

  On the other hand, this cooling system is configured to stop the driving of the electric pump 131 and the electric fan 132 when the temperature T1 of the cooling water 133 becomes equal to or lower than a preset driving stop temperature Td. The drive stop temperature Td is set to a temperature at which the motor generator 33 and the inverter 34 are excessively cooled so that the power consumption of the electric pump 131 does not increase, and is set to, for example, 40 ° C to 50 ° C.

  Although the arrangement order of the devices in the circuit is not limited, it is preferable that the cooling circuit 130 be a circuit separate from an engine cooling circuit (not shown) that cools the engine body 11. By the cooling circuit 130 being configured separately from the engine cooling circuit, the water-cooled motor generator 33 and the inverter 34 can be cooled to lower temperatures without being affected by the heat of the engine cooling circuit.

  Subsequently, the auto cruise mode will be described. This auto cruise mode is used particularly when traveling on an expressway, and a program stored in the control device 80 causes the HEV to travel automatically when the auto cruise operation switch 81 is turned on by the driver. It is a mode to operate on the street.

  Specifically, when the auto cruise operation switch 81 is turned on, the control device 80 acquires map information and vehicle weight acquired by the map information acquisition device 82 for engine travel, assist travel, motor travel, and inertia travel. In this mode, the HEV is automatically traveled by maintaining the vehicle speed V acquired by the wheel speed sensor 84 in a preset target speed range by timely selecting based on the vehicle weight M estimated by the acquisition device 83.

  In the auto-cruise mode, when the depression of the accelerator pedal is detected by the accelerator opening sensor 92, acceleration can also be performed by the driving force from the diesel engine 10. In addition, when the depression of the brake pedal is detected by the brake pedal opening degree sensor 93, the depression of the clutch pedal (not shown) is detected, or when the depression of the auto cruise operation switch 81 is released, the auto cruise mode is performed. Is released.

  The target velocity range is a range between the upper limit velocity vb and the lower limit velocity vc based on the target velocity va. The driver can set the target speed va, the upper limit speed vb, and the lower limit speed vc to any values, 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 a target The lower limit velocity vc is set to a velocity of -10 km / h to 0 km / h with respect to the target velocity va.

The map information acquisition device 82 communicates with a satellite positioning system (GPS), which is connected to the control device 80 respectively, to communicate with a means for acquiring the current position of the HEV, and communicates with a server in which three-dimensional road data is stored. It consists of a means for acquiring three-dimensional road data including the gradient θ of the traveling path and the traveling distance s, and a means for extracting the gradient θ and traveling distance s of the traveling path on which the HEV is traveling. As described above, a device for dividing a traveling distance of 5 km or less into traveling distances s every 500 m and acquiring a gradient θ for each traveling distance s, and a device dividing a traveling distance s for each gradient θ It can be illustrated.

  The specific configuration of the map information acquiring device 82 is not particularly limited as long as it has a function capable of acquiring at least the gradient θ of the traveling path and the traveling distance s. It is also possible to exemplify one that acquires the gradient θ of the traveling path and the traveling distance s from the three-dimensional road data. In addition, the gradient θ may be calculated based on the values acquired by the wheel speed sensor 84 and the acceleration sensor (G sensor) 85.

  The vehicle weight acquisition device 83 is stored in the control device 80, and a program for estimating the vehicle weight M when the motor travel at the time of start acceleration is performed by the control device 80, specifically, transmitted to the drive wheels 27 It is assumed that the output torque Tm of the motor generator 33 acquired by the inverter 34 in the motor traveling at the time of start acceleration and the rotation speed of the motor generator 33 acquire the rotational speed of the motor generator 33 A program for estimating the vehicle weight M can be exemplified based on the acquired vehicle acceleration (hereinafter, acceleration) a.

  The specific configuration of the vehicle weight acquisition device 83 is not particularly limited as long as the vehicle weight M of the HEV can be estimated. If the vehicle weight M is estimated on the basis of a, the vehicle weight M can be estimated even when the vehicle speed V is low (a velocity of 30 km / h or less), and rolling resistance of the traveling resistance, air resistance, and Since each of the uphill resistances can be nullified and the variables can be reduced, the vehicle weight M can be estimated more accurately and simply. In addition, the time of the start acceleration by motor travel includes the time of retreat of HEV.

  The control method of the auto cruise mode will be described below as the function of the control device 80. First, when the auto cruise operation switch 81 is turned on by the driver while the HEV is traveling, 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. One of engine running, assist running, motor running, and freewheeling is selected as appropriate.

  In the engine travel, the HEV travels with the driving force Fe transmitted from the diesel engine 10 to the propeller shaft 25 via the wet multi-plate 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 reduction mechanism 30. In motor travel, the wet multi-plate clutch 15 is disengaged, and the HEV travels with the driving force Fm from the motor generator 33. In freewheeling, the HEV travels 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 performs control to stop the injection of fuel and stop the diesel engine 10 while stopping the wet multi-plate clutch 15 during the inertia running, and the diesel engine 10 during the inertia running. Is maintained in the idling stop state.

  As described above, even if the first power steering pump 40 is stopped with the stopping of the diesel engine 10, the power steering 51 is always supplied to the steering unit 53 from the second power steering pump 45 connected to the propeller shaft 25. While the HEV is traveling, the diesel engine 10 can be stopped without stopping the steering assist. Therefore, during the inertia running, the wet multi-plate clutch 15 is disconnected and the fuel injection is stopped so that the diesel engine 10 is stopped in the idling stop state, whereby the fuel consumption during the inertia running can be reduced.

  In addition, since the exhaust of exhaust gas 71 from the exhaust valve 70 can be reduced by stopping the diesel engine 10 during coasting, the exhaust valve 70 is disposed, and the exhaust valve 70 is connected to the turbine via the exhaust manifold 72. It is possible to suppress a decrease in the purification capability of the exhaust gas purification device 75 that purifies the exhaust gas 71 that has driven the engine 74. Thus, when the purification capacity of the exhaust gas purification device 75 decreases, fuel that does not contribute to the driving force of the HEV is injected to raise the temperature of the exhaust gas 71, and the purification capacity of the exhaust gas purification device 75 is recovered. As the opportunity for regeneration is reduced, the fuel consumption necessary for the regeneration can also be reduced. As this exhaust gas purification device 75, for example, a collection device for collecting particulate matter in the exhaust gas 71 can be exemplified, and accumulation of particulate matter on the collection device is suppressed during motor travel and inertia travel. As a result, it is possible to suppress the fuel consumption necessary for the regeneration of the collection device.

  In addition, since the wet multi-disc clutch 15 is disengaged and the fuel injection is stopped to stop the diesel engine 10 during inertia running, the rotational power of the propeller shaft 25 is the rotational drag of the diesel engine 10. Since the decrease due to the above can also be avoided, it is possible to further improve the fuel consumption by reducing the loss of energy during motor travel and coasting.

  In addition, the control device 80 may perform control to stop the diesel engine 10 by stopping the fuel injection while stopping the wet multi-plate clutch 15 while the motor is traveling.

  As described above, by stopping the diesel engine 10 as in the case of the motor traveling as well as the inertia traveling, it is possible to reduce the fuel consumption during the motor traveling and to suppress the decrease in the purification capability of the exhaust gas purification device 75. Can be further improved.

  In such HEV, control device 80 predicts the presence or absence of downhill road L1 on which vehicle speed V increases based on the map information and vehicle weight M, and selects the coasting on the predicted downhill road L1 and the inertia thereof It is configured to perform control to maintain the vehicle speed V within the target speed range by operating a regenerative brake that generates regenerative power by the motor generator 33 while traveling. Further, the control device 80 lowers the regenerative torque Tm of the motor generator 33 before the state of charge Ce of the battery 35 becomes larger than the state of maximum charge Cmax at a halfway position on the descending slope L1, and stops the diesel engine 10. Is configured to perform control to cool the water-cooled motor generator 33 and the inverter 34 by driving the electric pump 131 with the generated electric power of the alternator 17 with the wet multi-plate clutch 15 connected. .

  Further, in the HEV, preferably, the control device 80 is configured to perform control of driving the electric fan 132 with the electric power generated by the alternator 17 when driving the electric pump 131.

  The downward slope L1 is a steep downhill where the gradient θ1 is steep, the force in the forward direction by the gravitational acceleration applied to the vehicle body is greater than the travel resistance, and the vehicle speed V is assumed to be the inertia run with the diesel engine 10 stopped. It is a descending slope which is predicted to increase, that is, to maintain the vehicle speed V at or above the lower limit velocity vc. As such a descending slope L1, for example, when the vehicle weight M of the HEV is 25t, it is possible to exemplify a descending slope having a gradient θ1 of 2% or more and a traveling distance s1 of 500 m or more.

The appropriate operating range (SOC) of the charging state Ce of the battery 35 is determined by the type of the battery 35, and the maximum charging state Cmax referred to herein means the upper limit of the operating range. The high charge state Ch means a state set higher than the half charge state and lower than the maximum charge state Cmax. Therefore, for example, when the charge state of the battery 35 is 0% for full discharge and 100% for full charge, the maximum charge state Cmax is 70% or more and 90% or less, and the high charge state Ch is 50 % Refers to the state of less than 70%.

  The control method in the auto cruise mode of the HEV will be described below as the function of the control device 80 based on the flowchart shown in FIG. This control method is performed while the HEV is traveling on the traveling road in the auto cruise mode.

  First, in step S10, the vehicle speed V increases on the forward traveling road based on the slope θ and the traveling distance s acquired by the control device 80 by the map information acquisition device 82 and the vehicle weight M estimated by the vehicle weight acquisition device 83. It is determined whether there is a downhill road L1 to be performed. If it is determined in step S10 that there is no downhill road L1, this control method is completed, while if it is determined that there is downhill road L1, the process proceeds to step S20.

  Next, in step S20, the control device 80 selects coasting as traveling of the HEV on the downhill L1. Then, the control device 80 disconnects the wet multi-plate clutch 15 and stops the diesel engine 10 by stopping the fuel injection.

  Next, in step S30, the control device 80 operates a regenerative brake that regenerates the motor generator 33. This step S30 may be performed at the timing to maintain the vehicle speed V in the target speed range, and may be performed simultaneously with the inertia running started in step S20, or may be performed when the vehicle speed V exceeds the upper limit speed vb. Good. As described above, when the vehicle speed V is maintained in the target speed range by applying the braking force in the inertia running on the downhill L1 where the vehicle speed V increases, the regeneration opportunity of the motor generator 33 is obtained by operating the regenerative brake first. As it increases, it is advantageous to reduce fuel consumption. The regenerative torque Tm of the motor generator 33 in this step S30 is set to a high regenerative torque Th at which the regenerative efficiency is maximum or the torque is maximum.

  Next, in step S40, the control device 80 determines whether the state of charge Ce of the battery 35 has become equal to or higher than the high state of charge Ch set lower than the maximum state of charge Cmax. When it is determined in step S40 that the state of charge Ce of the battery 35 is less than the high state of charge Ch, the process returns to step S30 to operate the regenerative brake with high regenerative torque Th while the state of charge Ce of the battery 35 is high in charge state Ch or more If it is determined that the condition is, the process proceeds to step S50.

  Next, in step S50, the control device 80 sets the regenerative torque Tm of the motor generator 33 to the low regenerative torque Tl and throttles the regenerative brake. The control for reducing the regenerative brake is specifically described. The regenerative torque Tm is set to map information and the high regenerative torque Th such that the state of charge Ce of the battery 35 becomes the maximum state of charge Cmax at a midway position of Assuming that the regenerative brake is operated to the end point of the descending slope L1 based on the vehicle weight M, control is performed to set the low regenerative torque Tl at which the state of charge Ce of the battery 35 becomes the maximum state of charge Cmax at the end point. .

  The low regenerative torque Tl is preferably calculated based on map data based on the slope θ1 to the end point of the descending slope L1, the traveling distance s1, the vehicle weight M, and the difference between the vehicle speed V and the target speed va. The low regenerative torque Tl has a negative correlation with each of the gradient θ1, the travel distance s1, the vehicle weight M, and the difference between the vehicle speed V and the target speed va.

  Next, in step S60, the controller 80 brings the wet multi-plate clutch 15 from the disconnected state to the connected state. At this time, the rotational power of the propeller shaft 25 is gradually transmitted to the crankshaft 13 via the transmission 20, and the crankshaft 13 rotates to operate the engine brake.

  Next, at step S70, the crankshaft 13 is rotated at step S60 to drive the alternator 17 for regeneration. The resistance of the regenerative drive of the alternator 17 is transmitted to the propeller shaft 25 as a braking force. At this time, the first power steering pump 40 is also driven, and a braking force by the driving is applied to the propeller shaft 25.

  Next, at step S80, the control device 80 drives the electric pump 131 to complete this control method. The cooling water 133 is circulated in the cooling circuit 130 by the drive of the electric pump 131 in this step S80 to cool the water-cooled inverter 34 and the motor generator 33. Further, in this step S80, it is preferable to drive the electric pump 131 and drive the electric fan 132 to cool the battery 35 and the radiator 134 with the cooling air of the electric fan 132.

  When the temperature T1 of the cooling water 133 is equal to or lower than the drive stop temperature Td, if the control device 80 performs control to stop the electric pump 131 and the electric fan 132, consumption of the electric pump 131 and the electric fan 132 Since the power can be suppressed, it is advantageous to the improvement of fuel consumption.

  4 shows the relationship among the vehicle speed V in the auto cruise mode, the output torque Te of the diesel engine 10, the output torque Tm of the motor generator 33, the charge state Ce of the battery 35, the temperature T1 of the cooling water 133 of the cooling system, and the elevation H. An example is shown. The negative output torque Te of the diesel engine 10 indicates the engine brake (including the braking force by the alternator 17 and the first power steering pump 40), and the negative output torque Tm of the motor generator 33 indicates the regenerative torque. It shall be.

  Assist traveling is performed on the uphill road before the downhill road L1, and the temperature T1 of the cooling water 133 of the cooling system rises. In addition, the state of charge Ce of the battery 35 is reduced due to the power consumption by the motor generator 33. While traveling on the uphill, the control device 80 acquires the gradient θ1 and the traveling distance s1 acquired by the map information acquisition device 82, and the vehicle weight M estimated by the vehicle weight acquisition device 83. Next, the control device 80 predicts a downhill road L1 on which the vehicle speed V increases when it is assumed that the vehicle has been coasted based on them (step S10).

  When the downhill road L1 starts at the point A, the control device 80 causes the HEV to start coasting (step S20). At the same time, the motor generator 33 generates regenerative power to operate the regenerative brake (step S30). At this time, the control device 80 sets the regenerative torque Tm of the motor generator 33 to a high regenerative torque Th at which the regenerative efficiency is maximum.

  Next, the controller 80 monitors the state of charge Ce of the battery 35 from the point A to the point B. At this time, since the regenerative brake is operated, the electric power generated by the motor generator 33 is charged to the battery 35, and the charge state Ce of the battery 35 is increased. In addition, the temperature T1 of the cooling water 133 of the cooling system also rises.

  Then, when the control device 80 determines that the state of charge Ce of the battery 35 is higher than the state of high charge Ch at point B (step S40), regenerative braking is performed from point B to point C to point C at the end point of the downhill. Low regenerative torque Tl that is predicted that the state of charge Ce of the battery 35 will be the maximum state of charge Cmax at point C, and the regenerative torque Tm of the motor generator 33 is calculated. The torque Tl is set (step S50).

In addition, when the regenerative brake is squeezed at point B, the control device 80 connects the wet multi-plate clutch 15 while maintaining the stop of the diesel engine 10 (step S60) and starts the power generation of the alternator 17 (step S60) S70) The electric pump 131 and the electric fan 132 are driven by the electric power obtained by the power generation (step S80).

  Then, the cooling water 133 is circulated by driving the electric pump 131, the cooling water 133 discharged from the electric pump 131 is cooled by the radiator 134, and then heat exchange is performed by the water-cooled inverter 34 and the motor generator 33, The inverter 34 and the motor generator 33 are cooled by heat exchange at that time. Thereby, temperature T1 of the cooling water 133 falls from B point to C point. Further, by driving the electric fan 132, the battery 35 is cooled by the cooling air generated thereby.

  By applying the braking force by the engine brake including the regenerative braking force of the alternator 17 and the driving braking force of the first power steering pump 40 by connecting the wet multi-plate clutch 15 between the point B and the point C, Squeeze the regenerative brake to compensate for the decreasing braking force.

  Next, at the point C, when the downhill path L1 ends, the control device 80 stops the regenerative brake and the engine brake that are in operation, and starts injecting the fuel to the cylinder 12 to start the diesel engine 10. Further, since the temperature T1 of the cooling water 133 of the cooling system is equal to or lower than the drive stop temperature Td, the drive of the electric pump 131 and the electric fan 132 is stopped. The charging state Ce of the battery 35 at this time is the maximum charging state Cmax.

  Since the control as described above is performed, when the regenerative brake is operated during the inertia running with the diesel engine 10 stopped on the downhill L1 to maintain the vehicle speed V within the target speed range, the middle of the downhill L1 The regenerative torque Tm of the motor generator 33 is lowered before the state of charge Ce of the battery 35 reaches the maximum state of charge Cmax at the position of b, so that the battery 35 reaches the state of maximum charge Cmax at the middle position of the downhill L1. Thus, the overcharge of the battery 35 can be suppressed by setting the state of charge Ce to the maximum state of charge Cmax at the end point of the descending slope L1.

  In addition, on the downhill road L1, while suppressing the fuel consumption by driving the electric pump 131 without consuming the fuel, the water-cooled motor generator 33 and the water-cooling system are forced regardless of the temperature T1 of the cooling water 133 of the cooling system. The inverter 34 can be cooled. At the same time, the battery 35 can also be cooled by the electric fan 132.

  Thereby, the deterioration of the battery 35 can be suppressed, and in addition to the reduction effect of the fuel consumption by the stop of the diesel engine 10 during the inertia running and the power generation of the alternator 17 by the power transmitted from the propeller shaft 25 Since the temperature T1 of the cooling water 133 can be maintained at a low state, deterioration due to the temperature of the motor generator 33, the inverter 34 and the battery 35 can be avoided, and the output of the motor generator 33 is Since it is possible to avoid the suppression and to maximize the regenerative braking force and the assist force of the motor generator 33, the fuel consumption can be further improved.

  Moreover, even if the regenerative braking force of the regenerative brake is decreased during the inertia running with the diesel engine 10 stopped on the downhill L1, the wet multi-plate clutch 15 is engaged while maintaining the stop of the diesel engine 10 and the alternator 17 Since it is possible to apply the braking force by the power generation of the alternator 17, it is possible to maintain the braking force, so that the use of the foot brake when maintaining the vehicle speed V in the target speed range The frequency can be reduced to improve the life of the foot brake.

In this embodiment, the motor generator 33 is regenerated from the point A which is the start point of the downhill L1 to operate the regenerative brake, but the vehicle speed V exceeds the upper limit speed vb from the start of traveling of the downhill L1. At times, the regenerative brake may be operated. Also, if the vehicle speed V exceeds the upper limit speed vb at a halfway position on the downhill L1 even if both the regenerative brake and the engine brake with the wet multi-plate clutch 15 operated, the exhaust brake, compression Release brakes and auxiliary brakes, such as retarders, may be actuated to reduce the opportunity to actuate the foot brakes.

  FIG. 5 is a flowchart illustrating another example of the control method in the above-described HEV in the auto cruise mode. In step S40 of the above control method, step S50 to step S80 are performed when it is determined that the state of charge Ce of the battery 35 has become the high state of charge Ch or more, but here, after step S40. It is configured to predict whether or not the state of charge Ce of the battery 35 will be the maximum state of charge Cmax at a midway position of the descending slope L1, and perform step S50 and subsequent steps when predicting that the state of charge Cmax will be the maximum state of charge Cmax.

  That is, assuming that the control device 80 actuates the regenerative brake during inertia travel on the downhill L1 based on the map information and the vehicle weight M, the charge state Ce of the battery 35 is in the middle of the downhill L1. Steps S50 to S80 are performed when it is predicted that the maximum charge state Cmax is greater than the maximum charge state Cmax.

  In step S90 in the flowchart shown in FIG. 5, assuming that the control device 80 operates the regenerative brake during coasting on the downhill L1 based on the map information and the vehicle weight M, at a halfway position of the downhill L1. It is predicted whether the state of charge Ce of the battery 35 becomes larger than the maximum state of charge Cmax.

  In step S90, the control device 80 determines the slope θ1 from the point where the charge state Ce is equal to or higher than the high charge state Ch in step S40 to the end point of the downhill L1, travel distance s1, vehicle weight M, vehicle speed V, and Based on map data based on the difference between the target speeds va, it is predicted whether the state of charge Ce will be larger than the maximum state of charge Cmax. The low regenerative torque Tl is estimated for each of the gradient θ1, the travel distance s1, the vehicle weight M, and the difference between the vehicle speed V and the target speed va depending on whether the state of charge Ce is greater than the maximum state of charge Cmax. The correlation is positive.

  Thus, when it is configured to predict whether or not the state of charge Ce will be the maximum state of charge Cmax at the middle position of the descending slope L1, the case where the state of charge Ce does not reach the maximum state of charge Cmax at the middle position Since the opportunity to consume the fuel and charge the battery 35 can be reduced by increasing the amount of power generation by the regenerative brake, the fuel consumption can be further improved. On the other hand, when the state of charge Ce is the maximum state of charge Cmax, the deterioration of the battery 35 can be avoided and the output suppression of the motor generator 33 can be avoided to further improve the fuel efficiency.

DESCRIPTION OF SYMBOLS 10 diesel engine 15 clutch apparatus 17 alternator 20 transmission 25 propeller shaft 26 differential 27 drive wheel 30 deceleration mechanism 32 rotating shaft 33 motor generator 80 control apparatus 81 auto cruise operation switch 82 map information acquisition device 83 car weight acquisition device 84 wheel speed sensor 130 Cooling circuit 131 Electric pump 133 Cooling water 134 Radiator Ce Charge state Cmax Maximum charge state L1 Downhill road

Claims (5)

A hybrid system having a propeller shaft that connects a transmission connected to a diesel engine via a clutch device and a differential that drives wheels, a hybrid system having a motor generator connected to the diesel engine and a battery via an inverter, and water cooled Cooling is performed by driving an electric pump driven by electric power generated by an alternator connected to the diesel engine when the temperature of the cooling water for cooling the motor generator and the inverter reaches or exceeds a preset driving start temperature In a hybrid vehicle including a cooling system for circulating water, a map information acquisition device for acquiring map information, a vehicle weight acquisition device for acquiring vehicle weight, a vehicle speed acquisition device for acquiring vehicle speed, and a control device,
The rotational shaft of the motor generator and the propeller shaft are connected via a reduction mechanism having the rotational shaft as an input shaft and the propeller shaft as an output shaft,
When the auto-cruise mode for maintaining the vehicle speed in a preset target speed range is set, the controller predicts, based on the map information and the vehicle weight, the presence or absence of a downhill road where the vehicle speed increases. ,
On the downhill road which has been predicted, the clutch device is disengaged and inertia running with the diesel engine stopped by stopping the injection of fuel is selected, and a regenerative brake for regenerative power generation by the motor generator is activated during the coasting. When maintaining the vehicle speed in the target speed range, the regenerative torque of the motor generator is throttled before the state of charge of the battery becomes larger than the state of maximum charge at a midway position on the downhill. The clutch device is engaged while maintaining the stop of the diesel engine to generate the alternator, and the electric power generated by the alternator drives the electric pump to cool the motor generator and the inverter. Is characterized by having a configuration to Lid vehicle.   The controller reduces the regenerative torque of the motor generator when the state of charge of the battery becomes lower than the maximum state of charge on the downhill and throttling the regenerative torque of the motor generator and stopping the diesel engine While maintaining the clutch device in a connected state, the alternator is generated, and the electric pump is driven by the electric power generated by the alternator to control the motor generator and the inverter to be cooled. The hybrid vehicle according to Item 1. It is assumed that the regenerative brake is operated during the coasting on the downhill road based on the map information and the vehicle weight after determining that the control state of the battery is higher than the high state of charge. And predict whether the state of charge of the battery will be greater than the maximum state of charge at a midway position on the downhill road,
When it is predicted that the state of charge of the battery becomes larger than the state of maximum charge at a halfway position on the downhill, the clutch device is squeezed while throttling the regenerative torque of the motor generator and maintaining the stop of the diesel engine. The hybrid vehicle according to claim 2, wherein the hybrid vehicle is configured to generate electric power from the alternator and drive the electric pump with the electric power generated by the alternator to cool the motor generator and the inverter. .   In the control device, when the regenerative torque of the motor generator is squeezed, from the high regenerative torque at which the charge state of the battery becomes the maximum charge state at the midway position of the downhill, the stop point of the downhill The control according to any one of claims 1 to 3, wherein, assuming that the regenerative brake is operated, control is performed to set a low regenerative torque at which the state of charge of the battery is predicted to be the maximum state of charge at the end point. The hybrid vehicle described in. When the auto cruise mode is set, the driving force transmitted from the diesel engine to the propeller shaft via the clutch device and the transmission, and the motor generator connected via the inverter to the battery via the speed reduction mechanism The engine travels with either one or both of the driving forces transmitted to the propeller shaft, the motor travel, and the assist travel, and the clutch device is disengaged and the diesel engine is stopped to stop the diesel The vehicle speed is set to a preset target speed range by timely selecting any of the engine and the free running of the motor generator without transmitting the driving force to the propeller shaft based on at least the map information including the slope and the vehicle weight. Maintain and drive automatically A method of controlling a hybrid vehicle that,
The presence or absence of a descending slope where the vehicle speed increases is predicted based on the map information and the vehicle weight, and the regenerative braking that is generated by the motor generator during the inertia running on the predicted descending slope is operated to In order to maintain the target speed range, the regenerative torque of the motor generator is throttled before the charge state of the battery becomes larger than the maximum charge state at a halfway position on the downhill, and the diesel engine is stopped. While the clutch device is connected to generate electric power while the alternator connected to the diesel engine is generated, and the electric power generated by the alternator drives the electric pump to circulate the cooling water, and the cooling water is circulated by the cooling water. It features cooling of the water-cooled motor generator and the inverter Control method for a hybrid vehicle to be.