JP6551021B2 - 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 the regenerative efficiency during high-speed driving as compared with the conventional vehicle, the regenerative braking force is maintained even when the state of charge of the battery becomes high, and the foot brake is controlled. The present invention relates to a hybrid vehicle that reduces use frequency 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 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 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 traveling at high speed (for example, 50 to 90 km / h), the transmission is shifted to the high speed stage, so that the power is transmitted through the high speed gear. 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 high efficiency point of power generation.

  In addition, in this HEV, it is not easy to convert a vehicle having only an existing engine into a HEV because it is necessary to largely change the layout of the powertrain components of the existing vehicle in order to arrange the motor generator. There was also a problem of that.

  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. Invented to connect.

  Further, the inventor paid attention to a regenerative brake that regenerates the newly devised HEV motor generator. If the state of charge of the battery that charges the motor generator is maintained at a high level, the battery deteriorates. Therefore, when the battery charge state is high, the battery charge state is maintained low by reducing the amount of power generation by the regenerative generation of the motor generator, but in this case, the regenerative braking force is reduced. As a result, the frequency of use of the foot brake increased, and there was a problem that the foot brake deteriorated.

JP 2002-238105 A

  An object of the present invention is a hybrid vehicle capable of reducing the frequency of use of a foot brake by maintaining a regenerative braking force even if the state of charge of a battery is increased, while improving the regeneration efficiency at high speed traveling 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. A hybrid system having a motor generator, an air tank for accumulating compressed air supplied from an air compressor connected to the diesel engine, and the air tank from the air compressor when the pressure of the air tank exceeds a preset upper limit pressure The unloader valve starts supplying compressed air from the air compressor to the air tank when the pressure of the air tank falls below a preset lower limit pressure. And a control device, wherein the rotating shaft of the motor generator and the propeller shaft are connected via a reduction mechanism having the rotating shaft as an input shaft and the propeller shaft as an output shaft, A high charge state in which the charge state of the battery is set lower than the maximum charge state when the control device operates the regenerative brake that generates electric power by regeneration using the motor generator and the electric air compressor connected to the battery The electric air compressor is driven by the electric power charged to the battery when it becomes larger, and control is performed to supply compressed air compressed by the electric air compressor to the air tank. It is said that.

  Further, a control method of a hybrid vehicle according to the present invention for achieving the above object comprises driving force transmitted from a diesel engine to a propeller shaft via a clutch device and a transmission, and a motor connected to a battery via an inverter. The pressure of the air tank is lower than a preset lower limit pressure in engine travel and assist travel traveling with at least the driving force from the diesel engine among the driving force transmitted from the generator to the propeller shaft via the reduction mechanism. Then, the control method of a hybrid vehicle, wherein the compressed air is supplied from an air compressor connected to the diesel engine, and the supply of the compressed air is stopped when the pressure of the air tank reaches a preset upper limit pressure or more. Genele When the regenerative brake for regeneratively generating power with the battery operates and the charge state of the battery becomes greater than the high charge state set lower than the maximum charge state, the electric air compressor is charged with the electric power charged to the battery And the compressed air compressed by the electric air compressor is supplied to the air tank.

  Note that an appropriate operating range (SOC) is determined for the state of charge of the battery depending on the type of battery, and the maximum state of charge here refers to the upper limit of the operating range. Therefore, the maximum charge state is, for example, 70% or more and 90% or less when the full charge is 0% and the full charge is 100%, and the high charge state is 50%. The above refers to the state of 70% 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 battery charge state becomes larger than the high charge state due to the electric power generated by operating the regenerative brake, the electric air compressor consumes the electric power charged in the battery. Since the compressor consumes electric power and the battery can charge new electric power, the regenerative braking force can be maintained high without narrowing the regenerative brake. The use frequency of the foot brake can be reduced by the use of the high regenerative braking force, so that deterioration of the foot brake can be suppressed.

  Furthermore, by using the electric air compressor to consume the electric power charged to the battery without throttling the regenerative brake, it is possible to reliably avoid that the battery charge state exceeds the maximum charge state. Deterioration can be prevented.

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. It is a flowchart explaining the control method of the relief valve in the control method of FIG. FIG. 4 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 pressure of an air tank, and an altitude when traveling on a downhill in the control method of FIG. 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. FIG. 7 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 pressure of an air tank, and an altitude when traveling on a downhill in the control method of FIG.

  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. There is. The HEV also includes an air supply system that operates the pneumatic device using the compressed air 65 accumulated in the air tank 64. 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. 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 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, 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. 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 power, and the battery 35 is charged.

  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 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 reduction gear 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 from the existing vehicle can be performed more easily than in the past. .

  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. The steering unit 53 assists the steering of the steering 54 using the supplied power steering fluid 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 on the upstream side of the first power steering pump 40 and the end of the second hydraulic circuit 47 on the upstream side of the second power steering pump 45 are illustrated as storing the power steerings 44 and 48. Not connected to reservoir tank. 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 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. 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 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, and by adjusting the relief valve, the setting discharge pressure of the second power steering pump 45 is smaller than the setting discharge pressure of the first power steering pump 40 Adjusted to the 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 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.

  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 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 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.

Next, the air supply system will be described. In this air supply system, the drive shaft of the air compressor 61 is connected to the crankshaft 13 of the diesel engine 10 by a V-belt, a gear, etc., and the air compressor 61 driven by the diesel engine 10 is a first pneumatic line. The compressed air 65 is pressure-fed to the air tank 64 via 63. The compressed air 65 accumulated in the air tank 64 is supplied to the pneumatic device via the pneumatic line. As this pneumatic device, an actuator for a clutch device (not shown), a foot brake, and an air suspension can be exemplified.

  Further, the air compressor 61 is provided with an unloader valve 62. The unloader valve 62 is connected to the air tank 64 by a third pneumatic pipe 67, and is operated by the action of the pressure pt of the air tank 64. Specifically, when the pressure pt of the air tank 64 becomes equal to or higher than the upper limit pressure pa set based on the durability of the air tank 64, the compressed air is released to allow the compressed air from the air compressor 61 to the air tank 64 to be released. When the pressure pt of the air tank 64 falls below the lower limit pressure pb set so as not to interfere with the operation of the pneumatic device, the supply of compressed air from the air compressor 64 from the air compressor 61 is stopped. It has started.

  The pressure sensor 87 is disposed in either the air tank 64 or the pneumatic line from the air tank 64 to the pneumatic device, and supplies the pressure of the compressed air 65 accumulated in the air tank 64 or each pneumatic device from the pneumatic line. The pressure of the compressed air 65 is acquired.

  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 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.

  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. In addition, when the depression of the brake pedal is detected by the brake pedal opening degree sensor 93, the depression of the clutch device pedal (not shown) is detected, or the depression of the auto cruise operation switch 81 is released, the auto cruise is performed. The mode is released.

  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 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 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. For example, 1 km ahead of the HEV 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.

Moreover, as the map information acquisition device 82, at least the slope θ of the traveling road and the traveling distance s
The specific configuration is not particularly limited as long as it has a function that can be acquired, for example, the one that acquires the gradient θ and the travel distance s of the travel path from the three-dimensional road data stored in the drive recorder. It can be illustrated. 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 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. 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 it has a function capable of estimating the vehicle weight M of the HEV. However, the output torque Tm and acceleration a during start acceleration by motor traveling are not limited. If the vehicle weight M is estimated based on the above, 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, the air resistance, and the uphill of the running resistance Since each of the 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 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. One of engine running, assist running, motor running, and freewheeling is selected as appropriate.

  In the engine running, HEV is run 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 the motor running, the wet multi-plate clutch 15 is disengaged and the HEV is run with the driving force Fm from the motor generator 33. 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 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 an 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, by setting the wet multi-plate clutch 15 in the disconnected state and stopping the injection of fuel during the inertia running, the diesel engine 10 is stopped in the idling stop state, whereby the fuel consumption during the inertia running can be reduced.

Further, 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 73 is disposed, and the exhaust valve 70 is passed through the exhaust manifold 72. And exhaust gas 7 driving the turbine 74
It is possible to suppress a decrease in the purification capability of the exhaust gas purification device 75 that purifies 1. 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 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. 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 reduce the loss of energy during motor travel and inertia travel and to further improve fuel consumption.

  Further, the control device 80 may perform control to stop the diesel engine 10 by stopping the fuel injection while making the wet multi-plate clutch 15 disengaged while the motor is running.

  As described above, by stopping the diesel engine 10 in 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 capacity of the exhaust gas purification device 75. Fuel consumption can be further improved.

  In such a HEV, the electric air compressor 68 connected to the battery 35 is provided, and when the control device 80 operates the regenerative brake that generates electric power by the motor generator 33, the charging state Ce of the battery 35 is the maximum charging state Cmax. The electric air compressor 68 is driven by the electric power charged to the battery 35 when it becomes larger than the high charge state Ch set lower than that, and the compressed air 65 compressed by the electric air compressor 68 is air tank 64 Control to supply the

  In the case where the vehicle speed V is maintained at a constant speed on the downhill road as the case where the regenerative brake is operated, more specifically, the auto cruise mode described above is set and the controller 80 controls the downhill road L1 to increase the vehicle speed V. The presence or absence is predicted based on the map information and the vehicle weight M, inertia travel is selected on the predicted descending slope L1, and the regenerative brake is activated during the inertia travel to maintain the vehicle speed V within the target speed range. It can be illustrated.

  In addition, it is assumed that this downhill L1 is a downhill where the gradient θ1 is steep, and the force in the forward direction due to the gravitational acceleration applied to the vehicle body becomes greater than the running resistance and makes the diesel engine 10 coast. It is a downhill road predicted to increase the vehicle speed V, that is, to maintain the vehicle speed V at or above the lower limit speed vc. As such a downhill road L1, for example, when the HEV vehicle weight M is 25 t, a downhill road where the gradient θ1 is 2% or more and the travel distance s1 is 500 m or more can be exemplified.

  The appropriate operating range (SOC) of the charging state Ce of the battery 35 is determined depending on the type of the battery 35, and the maximum charging state Cmax here refers to the upper limit of the operating range. Therefore, for example, when the charge state of the battery 35 is 0% full discharge and 100% full charge, the maximum charge state Cmax is 70% or more and 90% or less, and the high charge state Ch is 50%. % Or more and 70% or less.

  The HEV control method will be described below as a 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 travel path based on the gradient θ and travel 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. When it is determined in step S10 that there is no downhill road L1, the process returns to the start, whereas when it is determined that there is a 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 determines whether to operate the regenerative brake. Whether or not to operate the regenerative brake is determined by whether or not the starting point of the downhill road L1 has been reached, or by whether or not the vehicle speed V has exceeded the upper limit speed vb. If it is determined in step S30 that the regenerative brake is to be operated, the process proceeds to step S40.

  Next, in step S <b> 40, the control device 80 operates a regenerative brake for regenerative power generation of the motor generator 33. This step S40 may be performed at the timing at which the vehicle speed V is maintained in the target speed range, and may be performed at the same time when the inertia running is started in step S20, or even 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. This increases the fuel consumption. The regenerative torque Tm of the motor generator 33 in this step S40 is preferably set to a high regenerative torque Th at which the regenerative efficiency is maximum or the torque is maximum, and the short-time rating is performed until the limit time specified by the short-time rating. You may set it to make it a continuous rating, after regenerating with.

  Next, in step S50, the control device 80 determines whether or not the charging state Ce of the battery 35 has become higher than the high charging state Ch. If it is determined in step S50 that the state of charge Ce of the battery 35 is higher than the state of high charge Ch, the process proceeds to step S60.

  Next, in step S60, the control device 80 drives the electric air compressor 68 with the electric power charged in the battery 35. The electric power charged in the battery 35 in step S60 is consumed by driving the electric air compressor 68, and the increase in the state of charge 35 of the battery 35 becomes gradual. Then, the process returns to step S30. The regenerative braking force is maintained in a high state because the regenerative brake operated in step S40 is not throttled even if it is determined in step S50 that the state of charge Ce of the battery 35 is higher than the high state of charge Ch.

  On the other hand, when it determines with charge condition Ce of the battery 35 being below high charge condition Ch by step S50, it progresses to step S70. Next, at step S70, the control device 80 stops the drive of the electric air compressor 68, and the process returns to step S30.

  On the other hand, if it is determined in step S30 that the regenerative brake is not operated, the process proceeds to step S80. Next, at step S80, the control device 80 stops the operation of the regenerative brake. Next, in step S90, the control device 80 stops driving the electric air compressor 68 and returns to the start.

Further, in the HEV described above, the relief valve 69 disposed downstream of the electric air compressor 68 with respect to the flow of the compressed air 65 is provided, and the relief valve 69 is opened when the control device 80 drives the electric air compressor 68 It is desirable to be configured to perform control to make the pressure pt of 64 less than the upper limit pressure pa.

  The relief valve 69 is disposed between the electric air compressor 68 and the air tank 64, between the air tank 64 and the pneumatic device not shown, or in the air tank 64, and releases the compressed air accumulated in the air tank 64 to the outside when opened. When closed, the air tank 64 is a valve that stores compressed air.

  A control method of the relief valve 69 will be described below as a function of the control device 80 based on a flowchart shown in FIG. This control method is performed while the HEV is traveling on the road in the auto-cruise mode and the control method of FIG. 3 is being performed.

  First, in step S100, the control device 80 determines whether the electric air compressor 68 is driven. If it is determined in step S100 that the electric air compressor 68 is not driven, the process returns to the start, while if it is determined that the electric air compressor 68 is driven, the process proceeds to step S110.

  Next, in step S110, the control device 80 determines whether or not the pressure pt of the air tank 64 acquired by the pressure sensor 87 is equal to or higher than the upper limit pressure pa. If it is determined in step S110 that the pressure pt of the air tank 64 is equal to or higher than the upper limit pressure pa, the process proceeds to step S120.

  Next, in step S120, the controller 80 opens the relief valve 69. At this time, the controller 80 supplies compressed air from the air tank 64 to a pneumatic actuator (not shown), opens the relief valve 69 and returns to the start. When the relief valve 69 is opened, the pressure pt of the air tank 64 stops rising as the compressed air 65 is released from the relief valve 69 to the outside, or the pressure pg gradually drops, The pressure pt of the air tank 64 is less than the upper limit pressure pa.

  On the other hand, if it is determined in step S110 that the pressure pt is less than the upper limit pressure pa, the process proceeds to step S130. Next, in step S130, the control device 80 closes the relief valve 69 and returns to the start.

  FIG. 5 shows an example of 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 motor generator 33, the pressure pt of the air tank 64, and the altitude H. ing. It is assumed that the output torque Tm that becomes negative of the motor generator 33 indicates the regenerative torque.

  On the uphill road before the downhill road L1, assist traveling is performed, and the pressure pt of the air tank 64 is increased by driving the air compressor 61. In addition, the state of charge Ce of the battery 35 is reduced due to power consumption by the motor generator 33. While traveling on this uphill road, the control device 80 acquires the gradient θ1 and travel 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 the downhill road L1 at which the vehicle speed V increases when it is assumed that the vehicle is coasting 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 is regeneratively generated to operate the regenerative brake (steps S30 and S40).

Then, from point A to point B, the controller 80 controls the charge state Ce of the battery 35.
To monitor. At this time, since the regenerative brake is operated, the electric power generated by the motor generator 33 is charged in the battery 35, and the charged state Ce of the battery 35 rises. In addition, the wet multi-plate clutch 15 is disengaged and the driving of the air compressor 61 is also stopped by inertial running with the diesel engine 10 stopped, so that the pressure pt of the air tank 64 decreases.

  Next, the charging state Ce of the battery 35 becomes higher than the high charging state Ch at point B (step S50), and the control device 80 drives the electric air compressor 68 (step S60). By driving the electric air compressor 68, the motor generator 33 is regenerated and power is consumed, and the power charged in the battery 35 is consumed, so that the rise of the charge state Ce of the battery 35 becomes gentle. Further, since the compressed air 65 is supplied from the electric air compressor 68 to the air tank 64, the pressure pt of the air tank 64 increases.

  The control for driving the electric air compressor 68 to moderate the rise of the charge state Ce of the battery 35 is, specifically, the charge state Ce of the battery 35 at a high charge state Ch at a midway position of the descending slope L1. If it is assumed that the regenerative braking is operated without squeezing the regenerative braking force to the end point of the downhill L1 based on the map information and the vehicle weight M from the point B which has become higher, the battery 35 It is control which makes charge condition Ce the maximum charge condition Cmax.

  Therefore, the electric air compressor 68 may have a variable electric power load, and the electric power load is the difference between the slope θ1 to the end point of the downhill L1, the traveling distance s1, the vehicle weight M, and the difference between the vehicle speed V and the target speed va. It is preferable to calculate based on the map data based. The electric load of the electric air compressor 68 has a positive correlation with respect to 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, at point C, the pressure pt of the air tank 64 becomes equal to or higher than the upper limit pressure pa (step S110), and the control device 80 opens the relief valve 69 (step S120). By opening the relief valve 69, the compressed air 65 accumulated in the air tank 64 is discharged to the outside, and the pressure pt is maintained at the upper limit pressure pa.

  Next, at the point D, when the descending slope L1 ends, the regenerative brake that the control device 80 operates is stopped (step S80) and the driving of the electric air compressor 68 is stopped (step S90). To start the diesel engine 10 by starting fuel injection.

  As described above, when the charge state Ce of the battery 35 becomes larger than the high charge state Ch by the electric power generated by operating the regenerative brake, the electric air compressor 68 consumes the electric power charged to the battery 35. As a result, the electric air compressor 68 consumes power and the battery 35 can charge new power, so that the regenerative braking force can be maintained at a high level without narrowing the regenerative brake. Thereby, since the regenerative braking force can be maintained at a high state and the frequency of use of the foot brake can be reduced, deterioration of the foot brake can be suppressed.

  Further, by using the electric air compressor 68 to consume the electric power charged to the battery 35, the state of charge Ce of the battery 35 can be reliably prevented from exceeding the maximum state of charge Cmax without throttling the regenerative brake. Therefore, deterioration of the battery 35 can be prevented.

  Furthermore, the pressure pt of the air tank 64, which is lowered as the diesel engine 10 is stopped during the inertia running on the downhill road L1, is supplied with the compressed air 65 from the electric air compressor 68 to the air tank 64. Since pt can be maintained at a high level, the generation frequency of the compressed air 65 by the air compressor 61 can be reduced, and the fuel efficiency can be further improved.

  Moreover, even if the compressed air 65 is supplied from the electric air compressor 68 to the air tank 64, the relief valve 69 is opened, so the pressure pt of the air tank 64 can be made lower than the upper limit pressure pa, and the durability of the air tank 64 The pressure pt of the air tank 64 can be maintained at a high level without impairing the pressure.

  In this embodiment, the motor generator 33 is regeneratively generated from the point A which is the start point of the downhill L1 to operate the regenerative brake, but the vehicle speed V is the upper limit speed vb at the middle position of the downhill L1. It is good also as a structure which operates a regenerative brake when exceeding. If the vehicle speed V exceeds the upper limit speed vb at a halfway position on the downhill L1 even if the regenerative brake is activated, the engine brake with the wet multi-plate clutch 15 connected, exhaust brake, compression, etc. The opportunity to operate the foot brake by operating an opening brake and an auxiliary brake such as a retarder may be reduced.

  In addition, although the relief valve 69 is opened when the pressure pt of the air tank 64 becomes equal to or higher than the upper limit pressure pa, the timing of opening the relief valve 69 is not particularly limited as long as the pressure pt can be less than the upper limit pressure pa. For example, the relief valve 69 may be opened at the same time as the electric air compressor 68 is driven.

  FIG. 6 is a flowchart showing another example of the control method of HEV described above. In the above control method, the electric air compressor 68 is driven during operation of the regenerative brake, but the electric air compressor 68 may be driven while the operation of the regenerative brake is stopped.

  More specifically, the control device 80 starts the drive in which the pressure pt of the air tank 64 is set higher than the lower limit pressure pb when the state of charge Ce of the battery 35 is higher than the state of high charge Ch and the regenerative brake is not operating. When the pressure pc or lower, the electric air compressor 68 is driven by the electric power charged in the battery 35, and control is performed to supply the compressed air 65 compressed by the electric air compressor 68 to the air tank 64. Be done.

  The drive start pressure pc is set so as to drive the electric air compressor 68 before the unloader valve 62 is closed and the compressed air 65 compressed by the air compressor 61 is supplied to the air tank 64, and exceeds the lower limit pressure pb. In addition, it is preferably set to a value less than the upper limit pressure pa and closer to the lower limit pressure pb than the upper limit pressure pa. For example, when the lower limit pressure pb is set to 0.4 MPa or more and 0.6 MPa or less, the drive start pressure pc is set to 0.5 MPa or more and 0.7 MPa.

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

  First, in step S200, control device 80 determines whether or not charge state Ce of battery 35 is higher than high charge state Ch. If the charging state Ce is equal to or lower than the high charging state Ch in step S200, the process returns to the start, whereas if the charging state Ce is higher than the high charging state Ch, the process proceeds to step S210. This step S200 may be a step of determining whether or not the state of charge Ce of the battery 35 is the maximum state of charge Cmax.

  Next, in step S210, the control device 80 determines whether or not the pressure pt of the air tank 64 acquired by the pressure sensor 87 is equal to or lower than a preset driving start pressure pc. If the pressure pt exceeds the drive start pressure pc in step S210, the process returns to the start, whereas if the pressure pt is equal to or less than the drive start pressure pc, the process proceeds to step S220.

  Next, in step S220, the control device 80 drives the electric air compressor 68. When the electric air compressor 68 is driven at this time, the electric power charged in the battery 35 is consumed, so that the charged state Ce of the battery 35 is lowered and the compressed air 65 is supplied from the electric air compressor 68 to the air tank 64. As a result, the pressure pt of the air tank 64 increases.

  Next, in step S230, the control device 80 determines whether the state of charge Ce of the battery 35 is less than or equal to the high state of charge Ch. If the charge state Ce is higher than the high charge state Ch in step S230, the process returns to step S220. If the charge state Ce is equal to or lower than the high charge state Ch, the process proceeds to step S240.

  Next, in step S240, the control device 80 stops driving the electric air compressor 68, and returns to the start. Since the control shown in FIG. 5 is also performed at the same time, it is avoided that the pressure pt of the air tank 64 exceeds the upper limit pressure pa.

  FIG. 7 shows an example of 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 motor generator 33, the pressure pt of the air tank 64, and the altitude H. ing. In addition, the dashed-dotted line shows the thing of the prior art which does not perform said control.

  The downhill road L1 in front of the flat road L3 is coasting, and the regenerative brake is operated as described above, so that the state of charge Ce of the battery 35 is maximum at the point E, which is the end point of the downhill road L1. It rises to the charge state Cmax (step S200). Further, the pressure pt of the air tank 64 is maintained below the upper limit pressure pa by driving the electric air compressor 68 and opening / closing the relief valve 69.

  When the flat road L3 starts at point E, the control device 80 stops the regenerative brake that is operating and also stops the driving of the electric air compressor 68, and starts injection of fuel to the cylinder 12 to start the diesel engine 10 To start. At this time, since the unloader valve 62 is open, the driving torque Te of the diesel engine 10 is lowered by an amount that the driving resistance of the air compressor 61 is not applied, and the pressure pt of the air tank 64 is lowered.

  Next, at point F, the pressure pt of the air tank 64 becomes equal to or lower than the drive start pressure pc (step S210), and the control device 80 drives the electric air compressor 68 (step S220). At this time, since the compressed air 65 is supplied from the electric air compressor 68 to the air tank 64, the pressure pt of the air tank 64 increases. Further, the state of charge Ce of the battery is lowered because electric power is consumed by driving the electric air compressor 68.

  Next, at point G, the pressure pt of the air tank 64 becomes equal to or higher than the upper limit pressure pa, and the control device 80 opens the relief valve 69. By opening the relief valve 69, the compressed air 65 accumulated in the air tank 64 is discharged to the outside, and the pressure pt is maintained at the upper limit pressure pa or lower than the upper limit pressure pa.

  Next, when the charging state Ce of the battery 35 becomes equal to or lower than the high charging state Ch at point H (step S230), the control device 80 stops driving the electric air compressor 68.

  On the other hand, in the prior art, the pressure pt of the air tank 64 becomes the lower limit pressure pb at point I, the unloader valve 62 is closed, and the compressed air 65 compressed by the air compressor 61 is supplied to the air tank 64. Thereby, the drive load of the diesel engine 10 becomes high. Next, at point J, the pressure pt becomes the upper limit pressure pa, the unloader valve 62 opens, and the driving load of the diesel engine 10 decreases. Also, in the prior art, the charge state Ce of the battery 35 is maintained at the maximum charge state Cmax from the point E.

  As described above, when the state of charge Ce of the battery 35 is higher than the state of high charge Ch, the unloader valve 62 is closed, and the electric motor 65 is electrically driven before the compressed air 65 compressed by the air compressor 61 is supplied to the air tank 64. Since the air compressor 68 is driven, the driving loss of the diesel engine 10 due to the driving of the air compressor 61 can be reduced, so that the fuel consumption can be further improved.

  In addition, in particular, when the charge state Ce of the battery 35 is in the maximum charge state Cmax, the electric air compressor 68 consumes the power charged in the battery 35, thereby maintaining the battery in the maximum charge state Cmax. The charging state Ce of the battery 35 can be kept high while suppressing the deterioration of the battery 35.

DESCRIPTION OF SYMBOLS 10 diesel engine 15 clutch apparatus 17 alternator 20 transmission 25 propeller shaft 26 differential 27 drive wheel 30 reduction mechanism 32 rotating shaft 33 motor generator 61 air compressor 62 air loader 62 unloading tank 64 air tank 65 compressed air 68 electric air compressor 69 relief valve 80 control device 81 Auto cruise operation switch 82 Map information acquisition device 83 Vehicle weight acquisition device 84 Wheel speed sensor 87 Pressure sensor pa Upper limit pressure pb Lower limit pressure Cmax Maximum charge state Ch High charge state

Claims (5)

A hybrid system having a propeller shaft connecting a transmission connected to a diesel engine via a clutch device and a differential for driving wheels, a hybrid system having a motor generator connected to the diesel engine and a battery via an inverter, and the diesel engine An air tank for accumulating compressed air supplied from a connected air compressor, and stopping the supply of the compressed air from the air compressor to the air tank when the pressure of the air tank becomes equal to or higher than a preset upper limit pressure. In a hybrid vehicle including an unloader valve that starts supply of compressed air from the air compressor to the air tank when the pressure is equal to or lower than a preset lower limit pressure, 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,
An electric air compressor connected to the battery;
The battery is charged when the charge state of the battery becomes larger than the high charge state set lower than the maximum charge state when the control device operates a regenerative brake that generates regenerative electric power by the motor generator A hybrid vehicle characterized in that the electric air compressor is driven with the generated electric power and control is performed to supply compressed air compressed by the electric air compressor to the air tank. A relief valve located downstream of the electric air compressor with respect to the flow of compressed air;
The hybrid vehicle according to claim 1, wherein the control device performs control to open the relief valve so that the pressure of the air tank is less than the upper limit pressure when the electric air compressor is driven.   When the charge state of the battery exceeds the high charge state and the regenerative brake is not activated, and the pressure of the air tank becomes lower than the drive start pressure set higher than the lower limit pressure, the control device 3. The hybrid according to claim 1, wherein the electric air compressor is driven with electric power charged in the battery, and the compressed air compressed by the electric air compressor is supplied to the air tank. vehicle. The map information acquisition device for acquiring map information, the vehicle weight acquisition device for acquiring the vehicle weight, and the vehicle speed acquisition device for acquiring the vehicle speed;
Based on the map information and the vehicle weight, the control device predicts the presence or absence of a downhill road where the vehicle speed increases when an auto-cruise mode is set to maintain the vehicle speed within a preset target speed range. ,
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. To maintain the vehicle speed within the target speed range, control is performed to drive the electric air compressor when the charge state of the battery becomes greater than the high charge state at a midway position of the downhill. The hybrid vehicle according to any one of claims 1 to 3, which is configured to be performed. The driving force transmitted from the diesel engine to the propeller shaft via the clutch device and the transmission, and the driving force transmitted from the motor generator connected to the battery via the inverter to the propeller shaft via the reduction mechanism In at least the engine traveling and the assist traveling traveling by the driving force from the diesel engine, compressed air is supplied from the air compressor connected to the diesel engine when the pressure of the air tank becomes lower than a preset lower limit pressure. A control method of a hybrid vehicle, which stops the supply of compressed air when the pressure of the air tank becomes equal to or higher than a preset upper limit pressure,
When the regenerative brake generating regenerative power by the motor generator is activated, the battery is charged with electric power when the charge state of the battery becomes larger than the high charge state set lower than the maximum charge state. A control method of a hybrid vehicle, comprising driving an air compressor to supply compressed air compressed by the electric air compressor to the air tank.