JP2021130327A - Vehicle and method for controlling the same - Google Patents

Abstract

To provide a vehicle and a method for controlling the same which effectively utilize energy recovered from waste heat, thereby improving fuel consumption.SOLUTION: In a case where exhaust gas G is put in a first state of passing through an evaporator 16 by a three-way valve 11, a motor generator 3 is made independent by a power transmission mechanism 6, and power from an expander 17 is transmitted to a propeller shaft 5, when it is determined that a vehicle is in a braking state where only engine braking is applied, the first state is maintained by the three-way valve 11, the propeller shaft 5 is made independent from the power transmission system of the power transmission mechanism 6 by the power transmission mechanism 6, and the power from the expander 17 is transmitted to the motor generator 3.SELECTED DRAWING: Figure 4

Description

The present disclosure relates to vehicles and methods thereof.

A technique is disclosed in which a generator arranged separately from a motor generator, which is a power source for traveling a vehicle, is generated by using the power of the Rankine cycle system (see, for example, Patent Document 1).

In the technique described in Patent Document 1, the electric power generated by the Rankine cycle device is charged to the battery when the motor generator cannot obtain the regenerative electric power when accelerating or cruising the vehicle.

Japanese Unexamined Patent Publication No. 2002-115573

By the way, when only the engine brake is temporarily operated and the vehicle is decelerated while the power is being regenerated by the Rankine cycle system, the energy of the working fluid of the Rankine cycle system is high.

In the configuration in which power is generated from the Rankine cycle system only when the vehicle is accelerating or cruising as in the technique described in Patent Document 1, the energy of the working fluid is wasted when the vehicle is decelerated with only the engine brake activated.

An object of the present disclosure is to provide a vehicle and a control method thereof for improving fuel efficiency by effectively utilizing the energy recovered from exhaust heat.

The vehicle according to the embodiment of the present invention for achieving the above object is the power of the internal combustion engine, the electric generator, the Rankin cycle system for recovering the exhaust heat of the exhaust discharged from the internal combustion engine, and the power of the internal combustion engine. A power transmission mechanism that transmits power between the propeller shaft to be transmitted, the electric generator, the expander of the Rankin cycle system, and the propeller shaft, and a parameter acquisition device that acquires parameters related to the braking state of the vehicle. In a vehicle configured to include, and a control device, the Rankin cycle system comprises a bypass passage in which the exhaust bypasses the evaporator and a first state in which the exhaust passes through the evaporator or the exhaust passes through the bypass passage. The control device has a bypass valve for switching the passing second state, the control device is brought into the first state by the bypass valve, the electric generator is made independent by the power transmission mechanism, and the power from the expander is transmitted. When transmitting to the propeller shaft, when it is determined from the acquired value of the parameter acquisition device that only the engine brake is operating in the braking state, the bypass valve maintains the first state and the power transmission. The propeller shaft is made independent from the power transmission system of the power transmission mechanism by a mechanism, and the power from the expander is controlled to be transmitted to the electric generator.

Further, in the vehicle control method of the embodiment of the present invention using the vehicle, in the vehicle control method, the bypass valve is used to bring the vehicle to the first state, and the power transmission mechanism is used to make the electric generator independent. , A step of determining whether or not the power from the expander is transmitted to the propeller shaft, and a parameter relating to the braking state of the vehicle when the power from the expander is transmitted to the propeller shaft. The step of determining whether or not only the engine brake is operating in the braking state based on the acquired value, and when it is determined that only the engine brake is operating in the braking state, the bypass valve maintains the first state. After the step of transmitting the power from the expander to the electric generator and the power from the expander to the electric generator, the propeller shaft is transmitted from the power transmission system of the power transmission mechanism by the power transmission mechanism. It is a method characterized by including, and a step of making the independent.

According to the present disclosure, the energy recovered from the exhaust heat is effectively utilized to improve fuel efficiency.

It is a figure which illustrates the structure of the vehicle of this embodiment. It is a figure which illustrates the input / output of a control signal to a control device. It is a figure which illustrates the operation content of the vehicle corresponding to the disengagement state of the 1st to 3rd clutches. It is a flow figure which illustrates the control method of the vehicle of this embodiment. It is a flow diagram which illustrates the method of forcibly cooling a Rankine cycle system. It is a flow chart which continues from step S280 of FIG.

Hereinafter, the vehicle according to the embodiment of the present disclosure and the control method thereof will be described with reference to the drawings. In FIG. 1, the X direction is defined as the vehicle length direction, and the Y direction is defined as the vehicle width direction.

As illustrated in FIG. 1, the vehicle 1 of the present embodiment includes an engine (internal combustion engine) 2, a motor generator (motor generator) 3, a Rankine cycle system 4, a propeller shaft 5, and a power transmission mechanism 6. , And a control device 7.

The engine 2 obtains power for traveling of a vehicle by burning a mixture of fuel and fresh air injected from a fuel injection valve 2b in each cylinder 2a. In the exhaust passage 8 of the engine 2, the turbine of the turbocharged system (not shown), the exhaust aftertreatment device 9, and the Rankin cycle system 4 evaporate in order from the upstream side in the flow direction of the exhaust G discharged from the engine 2. The vessel 16 is arranged. The exhaust aftertreatment device 9 is a device in which various catalysts are arranged inside the exhaust gas aftertreatment device 9 to purify substances to be purified (for example, nitrogen oxides, fine particle substances, etc.) contained in the exhaust gas G by the various catalysts.

A bypass passage 10 in which the exhaust G bypasses the evaporator 16 is connected to the exhaust passage 8. A three-way valve (bypass valve) 11 is arranged at a branch point from the exhaust passage 8 to the bypass passage 10. The three-way valve 11 is a device that switches between a first state in which the exhaust gas G passes through the evaporator 16 and a second state in which the exhaust gas G passes through the bypass passage 10. Depending on the open / closed state of the three-way valve 11, the exhaust G flows to either the evaporator 16 or the bypass passage 10. An exhaust brake valve 49 is arranged in the exhaust passage 8 on the downstream side of the confluence of the exhaust passage 8 and the bypass passage 10.

The motor generator 3 is connected to the expander 17 and the propeller shaft 5 of the Rankine cycle system via the power transmission mechanism 6, and is also connected to the battery 13 via the inverter 12.

The motor generator 3 is driven by supplying the charged electric power to the battery 13. This driving force is transmitted to the propeller shaft 5 via the power transmission mechanism 6 to become power for traveling of the vehicle. Further, this driving force is transmitted to the expander 17 via the power transmission mechanism 6 to start the expander 17.

The motor generator 3 generates electricity by transmitting the inertial force of the propeller shaft 5 and the driving force of the expander 17 via the power transmission mechanism 6. The electric power obtained by this power generation is charged to the battery 13 via the inverter 12.

The Rankine cycle system 4 is a system that recovers the exhaust heat of the exhaust G by exchanging heat between the working fluid (for example, cooling water) W of the system 4 and the exhaust G. The Rankine cycle system 4 includes a pump (driving device) 15, an evaporator 16, an expander 17, a condenser 18, and a tank (a storage device for working fluid) in order from the flow direction of the working fluid W in the flow path 14 in which the working fluid W circulates. ) 19.

The pump 15 is a device that pumps the working fluid W. The evaporator 16 is a device that recovers the exhaust heat of the exhaust G to the working fluid W by exchanging heat between the working fluid W and the exhaust G. The expander 17 is a device that converts the amount of heat of the working fluid W into a driving force and outputs it. The condenser 18 is a device that cools the working fluid W by exchanging heat between the working fluid W and a cooling medium (for example, cooling water). The tank 19 is a device for storing the working fluid W.

The propeller shaft 5 is connected to the engine 2 via the engine clutch 20 and the transmission 21, and is also connected to the drive wheels (not shown) via a differential gear or a drive shaft (not shown). Further, the propeller shaft 5 is connected to the motor generator 3 and the expander 17 via the power transmission mechanism 6.

The engine clutch 20 is a device for switching whether or not the power of the engine 2 can be transmitted to the propeller shaft 5. When the engine clutch 20 is in contact with the engine clutch 20, unless the transmission 21 is in the neutral state, the engine 2, the transmission 21 and the propeller shaft 5 are connected, and the power of the engine 2 is transmitted to the propeller shaft 5. When the engine clutch 20 is disengaged, the engine 2, the transmission 21, and the propeller shaft 5 are disconnected, and the power of the engine 2 is not transmitted to the propeller shaft 5.

The transmission 21 is a device that shifts the rotation speed and torque of the engine 2 and transmits power to the propeller shaft 5. The wheel 22 is a passive wheel.

The power transmission mechanism 6 is a mechanism for transmitting power between the motor generator 3, the expander 17, and the propeller shaft 5. The power transmission mechanism 6 includes a power input / output device 23, a first clutch 24, a second clutch 25, a third clutch 26, and a power distribution device 27.

The power input / output device 23 is a device that inputs / outputs power to and from the propeller shaft 5. The power input / output device 23 has a drive shaft 28, and a gear 29 directly connected to a position in the middle of the propeller shaft 5 and a gear 30 arranged on the drive shaft 28 are meshed with each other on the outer circumferences. The power output from the propeller shaft 5 is transmitted to the drive shaft 28 via the gears 29 and 30. The power input to the propeller shaft 5 (power of the expander 17 or power of the motor generator 3) is transmitted to the drive shaft 28.

The first clutch 24 is a device interposed between the drive shaft of the expander 17 and the first drive shaft 31 of the power distribution device 27. When the first clutch 24 is in contact, power is transmitted in both directions between the drive shaft of the expander 17 and the first drive shaft 31. The second clutch 25 is a device interposed between the drive shaft of the motor generator 3 and the second drive shaft 32 of the power distribution device 27. When the second clutch 25 is in contact, power is transmitted in both directions between the drive shaft of the motor generator 3 and the second drive shaft 32. The third clutch 26 is a device interposed between the drive shaft 28 of the power input / output device 23 and the third drive shaft 33 of the power distribution device 27. When the third clutch 26 is in contact, power is transmitted in both directions between the drive shaft 28 and the third drive shaft 33.

Each of the first clutch 24, the second clutch 25, and the third clutch 26 is composed of a toeway clutch. The toeway clutch is configured to be able to switch between a contact state and a disconnection state by energizing electric power. When energized, the toeway clutch is in contact. When the energization is stopped, the toeway clutch is disengaged. When the towway clutch is in contact, both power transmission from one drive shaft to the other drive shaft and power transmission from the other drive shaft to one drive shaft are performed via the toeway clutch. .. When the toeway clutch is disengaged, the power transmission between the drive shafts is disconnected by the toeway clutch. That is, the two-way clutch switches between power transmission from one drive shaft to the other drive shaft, power transmission from the other drive shaft to one drive shaft, and disconnection of the power transmission depending on the disconnected state. It is a possible clutch. Since the toeway clutch is a meshing type clutch, it has higher strength and durability than a friction clutch.

The power distribution device 27 includes a first drive shaft 31, a second drive shaft 32, a third drive shaft 33, a first gear 34, and a second gear 35. The first drive shaft 31 and the third drive shaft 33 are directly connected via the first gear 34 to form the shaft of the first gear 34. As illustrated in FIG. 1, in the present embodiment, the shaft of the first gear 34 is simply a coupling (shaft joint) interposed between the first drive shaft 31 and the third drive shaft 33. It is used as one drive shaft. The second drive shaft 32 is directly connected to the second gear 35 to form the shaft of the second gear 35. The first gear 34 and the second gear 35 are meshed with each other on the outer circumference.

The configuration of the power distribution device 27 is not limited to the configuration of the present embodiment. For example, the second drive shaft 32 and the third drive shaft 33 are directly connected via the first gear 34 to form the first gear 34. It may be a shaft, and the first drive shaft 31 may be directly connected to the second gear 35 to be the shaft of the second gear 35. Further, another gear may be arranged between the first gear 34 and the second gear 35 so that the first gear 34 and the second gear 35 mesh with each other on the outer peripheral side via another gear.

That is, one of the third drive shaft 33, the first drive shaft 31, and the second drive shaft 32 is directly connected via the first gear 34 to form the shaft of the first gear 34, and the one drive shaft and the other drive shaft. The other different drive shaft may be directly connected to the second gear 35 to form the shaft of the second gear 35, and the first gear 34 and the second gear 35 may be configured to mesh with each other or on the outer peripheral side.

The power distribution device 27 is in a state of distributing the power input to any one of the first drive shaft 31, the second drive shaft 32, and the third drive shaft 33 to the other two drive shafts, or any of them. It is a device that combines the power input to the two drive shafts and outputs it to the other drive shaft. If no power is input to any of the drive shafts, the first gear 34 and the second gear 35 will not rotate. In the power distribution device 27 of the present embodiment, the first clutch 24 is formed by combining the first drive shaft 31, the second drive shaft 32, and the third drive shaft 33 with the first gear 34 and the second gear 35. , The second clutch 25 and the third clutch 26 are configured to passively change the power transmission state by controlling the disengagement state of each clutch.

As a state in which the power input to any one drive shaft is distributed to the other two drive shafts, for example, the power of the propeller shaft 5 input to the third drive shaft 33 is distributed to the first drive shaft 31 and the second drive shaft. There is a state of distributing to the drive shaft 32 and a state of distributing the power of the expander 17 input to the first drive shaft 31 to the second drive shaft 32 and the third drive shaft 33. The state in which the power input to any two drive shafts is combined and output to the other drive shaft is, for example, a third state in which the powers input to the first drive shaft 31 and the second drive shaft 32 are combined. There is a state of outputting to the drive shaft 33.

In the present embodiment, the drive shaft of the expander 17 is composed of a spline shaft having external teeth formed on the outer periphery thereof, and the external teeth and the internal teeth formed on the first clutch 24 are directly connected by a spline that meshes with each other. The drive shaft of the motor generator 3 is composed of a spline shaft having external teeth formed on the outer periphery thereof, and the external teeth and the internal teeth formed on the second clutch 25 are directly connected by a spline that meshes with each other.

A first unit 36 is formed in which a motor generator 3, an expander 17, a power distribution device 27, a first clutch 24, and a second clutch 25 are integrated. Further, a second unit 37 is formed in which the Rankine cycle system 4 excluding the expander 17 is integrated. The first unit 36 is fixed to the vehicle body frame 38 via the first bracket 39, and the second unit 37 is fixed to the vehicle body frame 38 via the second bracket 40. In the present disclosure, the "integrated unit" is a unit integrated before being fixed to the vehicle body frame 38.

In the first unit 36, it is desirable that the expander 17 is arranged on either the front side in the X direction or the rear side in the X direction via the power distribution device 27, and the motor generator 3 is arranged on the other side. It is more desirable to arrange 17 and arrange the motor generator 3 on the rear side in the X direction. By using the drive shaft of the expander 17 or the motor generator 3 as a spline shaft and directly connecting the clutches 24 and 25 to the clutches 24 and 25 with splines in this way, the state in which the expander 17 and the motor generator 3 are directly connected to the power distribution device 27 is compact. Can be done.

In the present embodiment, the first unit 36 is fixed to the inside of the vehicle body frame 38 in the vehicle width direction via the first bracket 39 behind the engine 2. The second unit 37 is fixed to the outside of the vehicle body frame 38 in the vehicle width direction via the second bracket 40 behind the engine 2 and behind the exhaust aftertreatment device 9. The first bracket 39 has a structure directly connected to the housing of the first unit 36, the expander 17, and the motor generator 3. The second bracket 40 has a structure directly connected to the housing of the second unit 37.

The first unit 36 and the second unit 37 are preferably arranged adjacent to each other in the vehicle width direction. By arranging these units 36 and 37 adjacent to each other, the expander 17 incorporated in the first unit 36 can be brought close to the second unit 37 to improve the heat retention.

After arranging the first unit 36 and the second unit 37 adjacent to each other in the vehicle width direction, the exhaust aftertreatment device 9 is regarded as one unit, and this unit and the second unit 37 are adjacent to each other in the vehicle length direction or the vehicle width direction. It is preferable to arrange them in a similar manner. By doing so, since the exhaust G flows into the evaporator 16 immediately after passing through the exhaust aftertreatment device 9, the heat exchange efficiency between the working fluid W and the exhaust G in the evaporator 16 can be improved. The arrangement positions of the inverter 12 and the battery 13 are not particularly limited to the arrangement positions of the present embodiment.

As illustrated in FIG. 2, the control device 7 includes a CPU (Central Processing Unit) that performs various information processing, an internal storage device that can read and write programs and information processing results used for performing the various information processing, and various types. It is hardware that consists of interfaces and the like. The control device 7 is electrically connected to various devices 3, 11, 20, 21, 24 to 26, and various sensors 41 to 48 described later.

The vehicle 1 of the present embodiment includes a first rotation speed sensor 41, a second rotation speed sensor (rotation speed acquisition device) 42, a temperature sensor 43, a pressure sensor 44, an engine rotation speed sensor 45, and an accelerator open. A degree sensor 46, a brake opening sensor 47, and a valve opening sensor 48 are provided. The first rotation speed sensor 41 is a sensor that acquires the rotation speed of the expander 17. The second rotation speed sensor 42 is a sensor that acquires the rotation speed of the motor generator 3. The temperature sensor 43 is a sensor that acquires the temperature of the working fluid W. The pressure sensor 44 is a sensor that acquires the pressure of the working fluid W. The engine speed sensor 45 is a sensor that acquires the speed of the engine 2. The accelerator opening sensor 46 is a sensor that acquires the opening degree (accelerator opening degree) of the accelerator pedal provided in the driver's seat of the vehicle. The brake opening sensor 47 is a sensor that acquires the opening degree (brake opening degree) of the brake pedal. The valve opening degree sensor 48 is a sensor that acquires the valve opening degree of the exhaust brake valve 49. The sensors 41 to 48 are examples of means for acquiring the values of the corresponding parameters, and the means for acquiring the values of these parameters are not limited to the sensors 41 to 48. Further, the rotation speed acquisition device may be any device that acquires the rotation speed of the expander 17 or the motor generator 3, and is not limited to the configuration of the present embodiment.

As illustrated in FIG. 3, in the vehicle 1 of the present embodiment, each of the first clutch 24, the second clutch 25, and the third clutch 26 is controlled by the control device 7. When the control device 7 disconnects the first clutch 24, the second clutch 25, and the third clutch 26, the power transmission between the expander 17, the motor generator 3, and the propeller shaft 5 is cut off. Become. This state is performed, for example, when the ABS or ASR is operated. ABS (Anti-lock Brake System) is a control for preventing the wheels 22 from locking during sudden braking. The ASR (Anti-slip regulator) is a control for preventing the wheel 22 from slipping at the time of sudden start or sudden acceleration. When these ABSs and ASRs are activated, the transmission of power between them is cut off to avoid input / output of extra torque to the propeller shaft 5.

When the control device 7 brings the first clutch 24 and the third clutch 26 into contact with each other and the second clutch 25 is disconnected, the motor generator 3 is made independent of the power transmission system in the power transmission mechanism 6, and the expander 17 and the expander 17 and the controller 7 are separated from each other. Power is transmitted between the propeller shafts 5. This state is performed, for example, when the power of the inflator 17 is assisted by the power of the engine 2 to drive the vehicle, or when the power of the engine 2 is used to start the inflator 17. By assisting the power of the expander 17, the load on the engine 2 can be reduced and the fuel consumption can be improved. By starting the expander 17 by the power of the engine 2, it is not necessary to provide a drive device dedicated to starting the expander 17, and space saving and cost reduction can be achieved.

When the control device 7 brings the first clutch 24 and the second clutch 25 into contact with each other and the third clutch 26 is disconnected, the propeller shaft 5 is made independent of the power transmission system in the power transmission mechanism 6, and the expander 17 and the expander 17 and the controller 7 are separated from each other. The power is transmitted between the motor generators 3. This state is performed, for example, when the motor generator 3 is generated by the power of the inflator 17, when the inflator 17 is started by the power of the motor generator 3, or when the vehicle is moved backward. By doing so, the motor generator 3 can be generated by effectively utilizing the power of the expander 17 without affecting the traveling state of the vehicle. Further, it is not necessary to provide a drive device dedicated to starting the expander 17, which can save space and cost.

When the control device 7 brings the second clutch 25 and the third clutch 26 into contact with each other and the first clutch 24 is disconnected, the expander 17 is made independent of the power transmission system in the power transmission mechanism 6, and the propeller shaft 5 and the propeller shaft 5 are separated from each other. The power is transmitted between the motor generators 3. This state is performed, for example, when the power of the engine 2 is assisted by the power of the motor generator 3 to drive the vehicle, or when the braking force of the propeller shaft 5 is used to generate power of the motor generator 3 when the vehicle is braked. .. By assisting the power of the motor generator 3 and generating the motor generator 3 by the power of the engine 2, the load on the engine 2 can be reduced and the fuel efficiency can be improved.

When the control device 7 brings the first clutch 24, the second clutch 25, and the third clutch 26 into contact with each other, the two of the expander 17, the motor generator 3, and the propeller shaft 5 move to the other one. It is in either a state of transmitting power or a state of transmitting power from one of these devices 3, 5 and 17 to the other two. In this state, for example, the power of the inflator 17 and the power of the motor generator 3 are used to assist the power of the engine 2 to drive the vehicle, or the power of the inflator 17 is used to drive the motor generator 3. This is performed when the power is generated and the power of the engine 2 is assisted.

The control device 7 makes it possible to select transmission or disconnection of power in the power transmission system in the power transmission mechanism 6 by switching the disengagement state of the first clutch 24, the second clutch 25, and the third clutch 26. The power transmission state in the power transmission system can be selected from the various states described above.

In the vehicle 1 of the present embodiment, in the power transmission mechanism for transmitting power between the engine 2, the motor generator 3, and the expander 17, each of the first clutch 24, the second clutch 25, and the third clutch 26 is towway. It consists of a clutch. Therefore, the power transmission mechanism 6 can be made lighter, thinner, shorter, and smaller than the mechanism in which those clutches are composed of friction type clutches. Further, the power transmission state of the power distribution device 27 is configured to change depending on the engagement and disengagement of the clutches 24, 25, and 26, respectively. That is, by simplifying the structure of the power transmission mechanism 6 so as to passively change the power transmission state only by engaging and disengaging the clutches 24, 25, and 26, the power transmission mechanism 6 can be made lighter, thinner, shorter, and smaller. Can be done.

Further, the vehicle 1 of the present embodiment has five power transmission states in the power transmission mechanism 6 as illustrated in FIG. Therefore, it is possible to select the optimum state from the power transmission states according to the running state of the vehicle 1 and the operating state of the engine 2. As a result, the frequency with which the power extracted by the Rankine cycle system 4 from the exhaust heat of the engine 2 can be used can be increased.

As described above, the vehicle 1 of the present embodiment can improve the fuel efficiency by the two effects of making the power transmission mechanism 6 lighter, thinner, shorter and smaller, and increasing the frequency of use of the power extracted from the exhaust heat.

The clutches 24, 25, and 26 are configured by a toeway clutch, and the power distribution device 27 is configured to have a first gear 34 and a second gear 35. By doing so, the power transmission mechanism 6 can be configured without using a planetary gear mechanism or a belt-type unauthorized transmission, so that the power transmission mechanism 6 can be made lighter, thinner, shorter, and smaller.

The motor generator 3, the Rankine cycle system 4, and the power transmission mechanism 6 are formed as the first unit 36 and the second unit 37, respectively. By doing so, it is possible to manufacture and assemble to the vehicle in units of units, and it is possible to improve the manufacturing efficiency and the assembling work efficiency.

The first unit 36 and the second unit 37 are fixed to the vehicle body frame 38. By doing so, as compared with the case where these units 36 and 37 are fixed to the engine 2, the weight of the vehicle is made uniform in the entire vehicle body, so that the running stability of the vehicle can be improved.

The vehicle 1 of the present embodiment is provided with a parameter acquisition device. The parameter acquisition device is a device that acquires parameters related to the braking state of the vehicle 1. In the present embodiment, the parameter acquisition device includes an accelerator opening sensor 46, a brake opening sensor 47, and a valve opening sensor 48. The parameters related to the braking state of the vehicle 1 are the presence / absence of operation of the exhaust brake based on the accelerator opening degree, the brake opening degree, and the valve opening degree of the exhaust brake valve 49. The exhaust brake is determined by the parameter acquisition device to be operating when the valve opening degree of the exhaust brake valve 49 is equal to or less than a preset threshold value, and is not operating when the valve opening degree exceeds this threshold value. Is determined. It is preferable that this threshold value is set to zero (the exhaust brake valve 49 is in the fully closed state). The parameter acquisition device may add a clutch sensor that acquires the engagement / disengagement state of the engine clutch 20. Further, the parameter acquisition device may add a switch sensor that acquires an on or off state of the exhaust brake switch provided in the driver's seat of the vehicle 1.

In the present embodiment, the control device 7 puts the exhaust G in the first state through the evaporator 16 by the three-way valve 11, makes the motor generator 3 independent by the power transmission mechanism 6, and transfers the power from the expander 17 to the propeller shaft. When transmitting to No. 5 (power regeneration), it is determined from the acquired value of the parameter acquisition device whether or not the braking state is such that only the engine brake is operating.

When the accelerator opening and the brake opening are zero and the exhaust brake is not operating, the control device 7 determines that only the engine brake is operating in the braking state. The control device 7 is in a braking state in which the exhaust brake is activated by a braking force larger than the braking force when only the engine brake is activated, regardless of the accelerator opening and the braking opening. , It is determined that the exhaust brake is operating in the braking state. When the exhaust brake is not operating, the accelerator opening degree is zero, and the braking opening degree is a positive value, the control device 7 determines that the engine brake and the friction brake are operating in the braking state. The control device 7 determines that the vehicle is not in the braking state when the exhaust brake is not operating, the brake opening degree is zero, and the accelerator opening degree is a positive value.

When the control device 7 determines that only the engine brake is operating in the braking state, the three-way valve 11 maintains the first state, and the power transmission mechanism 6 removes the propeller shaft 5 from the power transmission system of the power transmission mechanism 6. Independently, control (referred to as first control) for transmitting the power from the expander 17 to the motor generator 3 is performed. In the present embodiment, when it is determined that only the engine brake is operating when the first clutch 24 and the third clutch 26 are in contact with each other and the second clutch 25 is in the disengaged state, the first clutch 24 and the third clutch 26 and the second clutch 25 are engaged. The second clutch 25 is switched to the contact state, and the third clutch 26 is switched to the disengaged state.

The first control is a case where only the engine brake is temporarily operated and the vehicle 1 is decelerated while the power is being regenerated by the Rankine cycle system 4, and the energy of the working fluid W of the Rankine cycle system 4 is high. Sometimes done. Here, "temporary" means the time for maintaining a high energy state of the working fluid W. Further, in the case of braking only with the engine brake, the vehicle 1 may accelerate thereafter. Therefore, the energy of the working fluid W is maintained in a high state so as to maintain a state in which power can be taken out from the expander 17.

When the control device 7 determines that the exhaust brake is operating in the braking state, the three-way valve 11 puts it in the second state, and the power transmission mechanism 6 separates the expander 17 from the power transmission system of the power transmission mechanism 6. , Control (referred to as second control) to transmit the power of the propeller shaft 5 to the motor generator 3. In the present embodiment, when it is determined that the exhaust brake is operating when the first clutch 24 and the third clutch 26 are in contact with each other and the second clutch 25 is in the disengaged state, the second clutch 25 and the second clutch 25 are in the disengaged state. (3) The clutch 26 is switched to the contact state and the first clutch 24 is switched to the disengaged state.

The second control is performed when the exhaust brake is operated and the vehicle 1 is decelerated while the power is being regenerated by the Rankine cycle system 4, and when the Rankine cycle system 4 is stopped. Braking by the exhaust brake switches from a state in which power can be taken out from the expander 17 to a state in which power cannot be taken out, so that the energy of the working fluid W becomes low.

When the control device 7 determines that the engine brake and the friction brake are operating, the control device 7 puts it in the second state by the three-way valve 11, and the power transmission mechanism 6 separates the propeller shaft 5 from the power transmission system of the power transmission mechanism 6. Then, control (referred to as third control) is performed to transmit the power from the expander 17 to the motor generator 3. The switching of the disengaged state of the clutches 24 to 26 in the third control is the same as the switching of the disengaged state of the clutches 24 to 26 in the first control.

The third control is performed in order to secure the braking force of the vehicle 1 when the engine brake and the friction brake are operated in a state where the power is regenerated by the Rankine cycle system 4 to decelerate the vehicle 1. Braking by the engine brake and the friction brake gradually becomes a state in which the power cannot be taken out from the inflator 17 from the state in which the power can be taken out. Therefore, the third control is a control in which the power that can be taken out from the expander 17 is cut off by the motor generator 3.

In the present embodiment, when the rotation speed of the inflator 17 is larger than the rotation speed of the propeller shaft 5 and the power can be taken out from the inflator 17, the power is transmitted from the inflator 17 to the propeller shaft 5. Instead, the first control for transmitting power from the expander 17 to the motor generator 3 is performed.

When the control device 7 performs this first control, when the acquired value N of the second rotation speed sensor 42 exceeds the rotation speed threshold value N1, the motor generator 3 is generated by the power of the expander 17, while rotating. Control is performed to stop the power generation of the motor generator 3 when the number threshold value is N1 or less. The rotation speed threshold value N1 is set according to the characteristics of the motor generator 3. When the rotation speed threshold value N1 is exceeded, the motor generator 3 can generate electric power, and when the rotation speed threshold value N1 or less, the motor generator 3 generates electric power. It is preset as a value that cannot be set by an experiment or the like.

Depending on the characteristics of the motor generator 3, the rotation speed threshold value N1 may be set to zero. However, the motor generator 3 in which the rotation speed threshold N1 is set to a positive value is advantageous for miniaturization as compared with the motor generator 3 in which the rotation speed threshold N1 can be set to zero.

The control device 7 acquires the parameter acquisition device while the acquisition value N of the second rotation speed sensor 42 exceeds the rotation speed threshold value N1 to generate power for the motor generator 3 (while the first control is being performed). When it is determined that the operation of the engine brake is stopped based on the value, the first control is terminated. When the acquired value of the accelerator opening sensor 46 becomes a positive value (the accelerator pedal is depressed), it is determined that the operation of the engine brake is stopped.

After the end of the first control, the control device 7 stops the power generation of the motor generator 3 and puts it in the first state by the three-way valve 11, brings the first clutch 24 and the third clutch 26 into the contact state, and the second clutch 25. To the state of disengagement. In this way, the power transmission mechanism 6 makes the motor generator 3 independent from the power transmission system of the power transmission mechanism 6, and transmits the power from the expander 17 to the propeller shaft 5.

In the control device 7, except for the emergency stop of the Rankine cycle system 4, which will be described later, the clutches 24 to 26 are engaged and the exhaust gas is bypassed to the evaporator 16 until the first control to the third control are completed. Do not switch states.

Further, in the control device 7, the first state and the second state are set by the three-way valve 11 so that the actual state (temperature, pressure) of the working fluid W satisfies the condition (referred to as the first condition) preset by experiments or the like. To switch. When the first condition is satisfied, the power can be taken out from the expander 17, and when the first condition is not satisfied, the power cannot be taken out from the inflator 17. When the first condition is satisfied, the three-way valve 11 puts it in the first state, and when the first condition is not met, the three-way valve 11 puts it in the second state. The switching between the first state and the second state by the three-way valve 11 may be feedback control based on the first condition or feedforward control.

In the present embodiment, the first condition is that the acquired value of the temperature sensor 43 is within the preset temperature range, the acquired value of the pressure sensor 44 is within the preset pressure range, and the second rotation speed. It is satisfied when the acquired value of the sensor 42 is within the preset rotation speed range.

Here, the first temperature T1, the second temperature T2, the first pressure P1, and the second pressure P2 are defined as follows. The first temperature T1 is preset by an experiment or the like as an upper limit value of the temperature at which the expander 17 is operated by the working fluid W. The second temperature T2 is a value lower than the first temperature T1 and is preset by an experiment or the like as a lower limit of the temperature at which the expander 17 can operate. The first pressure P1 is preset by experiments or the like as an upper limit value of the pressure at which the expander 17 can be operated by the working fluid W. The second pressure P2 is set in advance by an experiment or the like as a value lower than the first pressure P1 and as a lower limit value of the pressure at which the expander 17 can operate.

The above temperature range is a range in which a value smaller than the first temperature T1 is an upper limit value and a value larger than the second temperature T2 is a lower limit value. The above pressure range is a range in which a value smaller than the first pressure P1 is an upper limit value and a value larger than the second pressure P2 is a lower limit value. By narrowing the temperature range and pressure range from the ranges defined by the first temperature T1, the second temperature T2, the first pressure P1 and the second pressure P2 in this way, the passage and bypass of the exhaust gas to the evaporator 16 are alternately alternated. It is possible to make it easier to continue the state of switching to.

The rotation speed range is a range in which the normal rotation speed of the expander 17 is the upper limit value and the minimum value of the rotation speed that can generate power according to the characteristics of the motor generator 3 is the lower limit value. The temperature range, pressure range and rotation speed range are set by experiments and the like.

The control method using the vehicle 1 of the present embodiment will be described with reference to the control flow illustrated in FIG. In the control flow in the first stage of the control flow of FIG. 4, the exhaust G is brought into the first state through the evaporator 16 by the three-way valve 11, and the motor generator 3 is made independent by the power transmission mechanism 6 to transfer the power from the expander 17. There is a step of determining whether or not the transmission is transmitted to the propeller shaft 5. In the control flow of FIG. 4, the exhaust G is brought into the first state through the evaporator 16 by the three-way valve 11, the motor generator 3 is made independent by the power transmission mechanism 6, and the power from the expander 17 is transmitted to the propeller shaft 5. This is a control flow that is periodically performed when it is determined that the system is operating.

When the control flow of FIG. 4 starts, in step S10, it is determined whether or not the accelerator pedal is not depressed (in the off state) and the accelerator opening degree is zero. If the accelerator pedal is in the off state (YES), the process proceeds to step S20. When the accelerator pedal is depressed (in the ON state) (NO), the process proceeds to return and the control flow ends.

In step S20, it is determined whether or not the brake pedal is not depressed (in the off state) and the brake opening degree is zero. If the brake pedal is in the off state (YES), the process proceeds to step S30. If the brake pedal is depressed (in the ON state) (NO), the process proceeds to step S40.

In step S30, it is determined whether or not the exhaust brake is not operating (is in the off state). Since this determination method has been described above, the description thereof will be omitted here. If it is determined that the exhaust brake is not operating (YES), the process proceeds to step S50. If it is determined that the exhaust brake is operating (NO), the process proceeds to step S120.

In step S40, the second state is set so that the exhaust G passes through the bypass passage 10. After performing step S40, the process proceeds to step S60.

In step S50, the exhaust gas G is brought into the first state of passing through the evaporator 16. After performing step S50, the process proceeds to step S60.

In step S60, the first clutch 24 and the second clutch 25 are brought into contact with each other. After performing step S60, the process proceeds to step S70. In step S70, the third clutch 26 is disengaged. After performing step S70, the process proceeds to step S80. In step S80, the motor generator 3 is generated by the power from the expander 17. After performing step S80, the process proceeds to step S90.

In step S90, it is determined whether or not the rotation speed of the expander 17 or the motor generator 3 exceeds the corresponding threshold value. In the present embodiment, it is determined whether or not the acquired value N of the rotation speed of the motor generator 3 exceeds the rotation speed threshold value N1. If the acquired value N exceeds the rotation speed threshold value N1 (YES), the process proceeds to step S100. If the acquired value N is equal to or less than the rotation speed threshold value N1 (NO), the process proceeds to step S110.

In step S100, the motor generator 3 is generated by the power of the expander 17. In step S110, the power generation of the motor generator 3 is stopped. After performing step S100 or S110, the process proceeds to return and ends this control flow.

In step S120, the second state is set so that the exhaust G passes through the bypass passage 10. After performing step S120, the process proceeds to step S130. In step S130, the first clutch 24 is disengaged. After performing step S130, the process proceeds to step S140. In step S140, the second clutch 25 and the third clutch 26 are brought into contact with each other. After performing step S140, the process proceeds to step S150. In step S150, the motor generator 3 is generated by the power from the propeller shaft 5 (braking regeneration). After executing step S150, the process proceeds to return and the present control flow is terminated.

Whether or not it is determined in step S10 that the accelerator pedal is in the off state, and the elapsed time from the determination time in step S10 is equal to or greater than a preset time threshold value before the determination in step S20 is performed. May be determined. The time threshold value is preset by an experiment or the like as a value at which it can be determined that the operation of the engine brake is started when the time threshold value is equal to or higher than this time threshold value. If the elapsed time is equal to or greater than the time threshold (YES), the process proceeds to step S20. If the elapsed time is less than the time threshold (NO), the determination using this time threshold is performed again after the lapse of a predetermined time. The determination using the time threshold value is set because the control of steps S50 to S80 is not performed immediately after the accelerator pedal is turned off. If the accelerator pedal or the brake pedal is depressed between the time of the determination in step S10 and the elapsed time becomes equal to or greater than the time threshold value, the process proceeds to return and the present control flow is terminated.

In the present embodiment, when the power from the expander 17 is transmitted to the propeller shaft 5 in steps S10 to S30, only the engine brake is operating according to the acquired value of the parameter related to the braking state of the vehicle 1. Corresponds to the step of determining whether or not. Steps S50 and S60 correspond to steps of maintaining the first state by the three-way valve 11 and transmitting the power from the expander 17 to the motor generator 3 when it is determined that only the engine brake is operating. Step S70 corresponds to a step in which the propeller shaft 5 is made independent from the power transmission system of the power transmission mechanism 6 by the power transmission mechanism 6 after the power from the expander 17 is transmitted to the motor generator 3.

In addition to the control flow of FIG. 4, the control device 7 periodically performs the control flow shown in FIGS. 5 and 6 during the operation of the engine 2. The control flow shown in FIGS. 5 and 6 is a flow for forcibly cooling the Rankine cycle system 4 to make an emergency stop, and is performed with priority over the control flow of FIG. 4 at the time of an emergency stop of the Rankine cycle system 4. The temperature of the working fluid W is acquired by the temperature sensor 43, and the pressure of the working fluid W is acquired by the pressure sensor 44.

When the control flow of FIG. 5 starts, in step S210, it is determined whether or not the temperature T of the working fluid W is equal to or lower than the first temperature T1. The first temperature T1 is preset by an experiment or the like as an upper limit value of the temperature at which the expander 17 is operated by the working fluid W.

When the temperature T of the working fluid W is equal to or lower than the first temperature T1 (YES), the process proceeds to step S220. When the temperature T of the working fluid W exceeds the first temperature T1 (NO), the process proceeds to step S250, and in step S250, the first index value α is set to 1 and the second index value β is set to 1. The process proceeds to step S220. The first index value α is an index value indicating a pressure abnormality of the working fluid W, and is set to 1 when there is concern about the pressure abnormality of the working fluid W, and to 0 when the pressure of the working fluid W is normal. The second index value β is an index value indicating a temperature abnormality of the working fluid W, and is set to 1 when there is concern about a temperature abnormality of the working fluid W and 0 when the temperature of the working fluid W is normal.

In step S220, it is determined whether or not the pressure P of the working fluid W is equal to or less than the first pressure P1. The first pressure P1 is preset by experiments or the like as an upper limit value of the pressure at which the expander 17 is operated by the working fluid W.

If the pressure P of the working fluid W is equal to or less than the first pressure P1 (YES), the process proceeds to step S230. When the pressure P of the working fluid W exceeds the first pressure P1 (NO), the process proceeds to step S260, the first index value α is set to 1 in step S260, and the process proceeds to step S230.

In step S230, it is determined whether or not the temperature T of the working fluid W is equal to or higher than the second temperature T2. The second temperature T2 is a value lower than the first temperature T1 and is preset by an experiment or the like as a lower limit of the temperature at which the expander 17 can operate.

If the temperature T of the working fluid W is equal to or higher than the second temperature T2 (YES), the process proceeds to step S240. When the temperature T of the working fluid W is less than the second temperature T2 (NO), the process proceeds to step S270, and after setting the first index value α to 0 and the second index value β to 0 in step S270. , Step S240.

In step S240, it is determined whether or not the pressure P of the working fluid W is equal to or higher than the second pressure P2. The second pressure P2 is set in advance by an experiment or the like as a value lower than the first pressure P1 and as a lower limit value of the pressure at which the expander 17 can operate.

When the pressure P of the working fluid W is equal to or higher than the second pressure P2 (YES), the process proceeds to step S290 in FIG. When the pressure P of the working fluid W is less than the second pressure P2 (NO), the process proceeds to step S280, the first index value α is set to 0 in step S280, and then the process proceeds to step S290.

In step S290, it is determined whether or not the first index value α is 1. When the first index value α is 1 (YES), the process proceeds to step S300 assuming that a pressure abnormality in the working fluid W has occurred, and the Rankine cycle system 4 is stopped in step S300. Examples of the stopping method include a method of bypassing the exhaust gas G to the evaporator 16 and a method of bypassing the working fluid W to the expander 17. After performing step S300, the process proceeds to step S310. If the first index value α is 0 (NO), the process proceeds to step S310.

In step S310, it is determined whether or not the second index value β is 1. When the second index value β is 1 (YES), it is assumed that the temperature abnormality of the working fluid W has occurred, and the process proceeds to step S320. When the second index value β is 0 (NO), the process proceeds to return and the present control flow is terminated.

In step S320, the pump 15 is driven at a preset first rotation speed. The first rotation speed is preset by experiments or the like as a value capable of cooling the working fluid W by setting the passing frequency of the working fluid W passing through the condenser 18 to a frequency based on the first rotation speed. NS. After executing step S320, the process proceeds to return and the present control flow is terminated.

In this way, the Rankine cycle system 4 is stopped when the pressure abnormality of the working fluid W occurs, and the Rankine cycle system 4 is not hindered by cooling the working fluid W when the temperature abnormality of the working fluid W occurs. It can be operated.

The determinations in steps S210, S220, S230, and S240 are in no particular order, and the order in which these steps S210 to S240 are performed is not limited to the order shown in FIG. Further, the determinations in steps S290 and S310 are in no particular order, and the order in which these steps S290 and S310 are performed is not limited to the order shown in FIG.

From the above, according to the vehicle of the present embodiment and the control method thereof, when only the engine brake is temporarily operated and the vehicle is decelerated while the power is being regenerated by the Rankine cycle system 4, the expander 17 is used. The motor generator 3 is generated by power. By doing so, it is possible to effectively utilize the energy recovered from the exhaust heat and improve the fuel efficiency.

Further, when only the engine brake is activated and the vehicle 1 decelerates, the three-way valve 11 maintains the first state in which the exhaust G passes through the evaporator 16. As a result, it is possible to avoid a situation in which the exhaust heat cannot be recovered when the vehicle 1 accelerates by releasing the braking of only the engine brake. Further, by doing so, the amount of energy used to drive the three-way valve 11 (for example, the amount of compressed air used) can be reduced, so that fuel efficiency can be improved.

Further, the power generation of the motor generator 3 by the power of the expander 17 is limited to the case where the acquired value N of the second rotation speed sensor 42 exceeds the rotation speed threshold value N1. By doing so, when a model capable of generating electricity only at a predetermined rotation speed or higher is used as the motor generator 3, the durability of the motor generator 3 is maintained without rotating the motor generator 3 in the rotation speed region where power generation is not possible. Deterioration can be suppressed.

After transmitting the power from the expander 17 to the motor generator 3, the power transmission mechanism 6 separates the propeller shaft 5 from the power transmission system of the power transmission mechanism 6. By doing so, the inflator 17 is not connected to both the propeller shaft 5 and the motor generator 3 (no load state), so that the inflator 17 can be prevented from over-rotating.

1 Vehicle 2 Engine (internal combustion engine)
2a Cylinder 2b Fuel injection valve 3 Motor generator (motor generator)
4 Rankine cycle system 5 Propeller shaft 6 Power transmission mechanism 7 Control device 8 Exhaust passage 9 Exhaust aftertreatment device 10 Bypass passage 11 Three-way valve (bypass valve)
12 Inverter 13 Battery 14 Flow path through which working fluid circulates 15 Pump (driving device)
16 Evaporator 17 Inflator 18 Condenser 19 Tank (working fluid storage device)
20 Engine clutch 21 Transmission 22 Wheel 23 Power input / output device 24 First clutch 25 Second clutch 26 Third clutch 27 Power distribution device 28 Drive shaft 29 Gear 30 Gear 31 First drive shaft 32 Second drive shaft 33 Third drive Shaft 34 1st gear 35 2nd gear 36 1st unit 37 2nd unit 38 Body frame 39 1st bracket 40 2nd bracket 41 1st rotation speed sensor 42 2nd rotation speed sensor (rotation speed acquisition device)
43 Temperature sensor 44 Pressure sensor 45 Engine rotation speed sensor 46 Accelerator opening sensor 47 Brake opening sensor 48 Valve opening sensor 49 Exhaust brake valve

Claims (6)

An internal combustion engine, an electric generator, a Rankin cycle system that recovers exhaust heat of exhaust exhausted from the internal combustion engine, a propeller shaft that transmits the power of the internal combustion engine, the electric generator, and the Rankin cycle system. In a vehicle configured to include an inflator, a power transmission mechanism for transmitting power between the propeller shafts, a parameter acquisition device for acquiring parameters related to a braking state of the vehicle, and a control device.
The Rankine cycle system has a bypass passage in which the exhaust bypasses the evaporator and a bypass valve that switches between a first state in which the exhaust passes through the evaporator or a second state in which the exhaust passes through the bypass passage.
When the control device is brought into the first state by the bypass valve, the electric generator is made independent by the power transmission mechanism, and the power from the expander is transmitted to the propeller shaft, the parameter acquisition When it is determined from the acquired value of the device that only the engine brake is operating, the bypass valve maintains the first state, and the power transmission mechanism transfers the propeller shaft from the power transmission system of the power transmission mechanism. A vehicle characterized in that the power from the expander is controlled to be transmitted to the electric generator independently. When the control device determines that the braking state is braking with a braking force larger than the braking force when only the engine brake is operated based on the acquired value of the parameter acquisition device, the bypass valve sets the second state. The vehicle according to claim 1, wherein the vehicle is controlled. The braking state in which the brake is applied by the large braking force is a braking state in which the exhaust brake is operating. In this braking state, the power transmission mechanism separates the expander from the power transmission system of the power transmission mechanism. The vehicle according to claim 2, wherein the vehicle is controlled to transmit the power from the propeller shaft to the electric generator. The vehicle according to any one of claims 1 to 3, wherein the parameters acquired by the parameter acquisition device are the accelerator opening degree, the brake opening degree, and the presence / absence of operation of the exhaust brake. A rotation speed acquisition device for acquiring the rotation speed of the expander or the motor generator is provided.
When the control device transmits the power from the expander to the motor generator, and the acquired value of the rotation speed acquisition device exceeds a preset rotation speed threshold, the power of the expander causes the power. The vehicle according to any one of claims 1 to 4, wherein the motor generator is generated while the motor generator is stopped when the number of revolutions is equal to or less than the threshold value. In the vehicle control method according to claim 1,
A step of setting the first state by the bypass valve, making the motor generator independent by the power transmission mechanism, and determining whether or not the power from the expander is transmitted to the propeller shaft.
When the power from the expander is transmitted to the propeller shaft, a step of determining whether or not only the engine brake is operating based on the acquired value of the parameter related to the braking state of the vehicle, and
When it is determined that only the engine brake is operating in the braking state, the bypass valve maintains the first state and transmits the power from the expander to the motor generator.
After transmitting the power from the expander to the motor generator, the step of making the propeller shaft independent from the power transmission system of the power transmission mechanism by the power transmission mechanism.
A vehicle control method comprising.

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