JP6182990B2 - Hybrid vehicle and control method thereof - Google Patents

Description

  The present invention relates to a hybrid vehicle including a hybrid system having a function of using both an internal combustion engine and a motor generator as a driving source for driving the vehicle. More specifically, the present invention maximizes the use of braking energy as charging energy. However, the present invention relates to a hybrid vehicle and a control method thereof that can sufficiently secure a braking torque during deceleration of the hybrid vehicle.

  In a hybrid vehicle (HEV) equipped with both an internal combustion engine and a motor generator, the vehicle is roughly divided into electricity generated by a generator driven by the internal combustion engine or driven by electricity from a battery charged with the generated electricity. There are series hybrid vehicles that use only an electric motor (travel motor) as a power source for travel, and parallel hybrid vehicles that use both an internal combustion engine and a motor generator (travel motor) as a power source for travel .

  In this hybrid vehicle, when the vehicle is in a decelerating state and regenerative energy can be recovered from the wheels of the vehicle, regenerative power generation is performed by the motor generator, and at this time, the vehicle is decelerated by the braking torque generated by the motor generator. When a large braking torque is required, there is a problem that the braking torque required for deceleration of the vehicle cannot be ensured only by the braking torque from the motor generator, and the hybrid vehicle cannot be reliably decelerated.

  In relation to this problem, for example, in order to improve drivability when the regenerative torque of the motor is used as a braking force, the regenerative torque generated by the regenerative power generation of the motor during deceleration using only the motor is used as the braking force. A deceleration comparison unit that compares the target deceleration set in advance with the actual deceleration due to the regenerative torque generated by regenerative power generation, and the deceleration even though the motor is generating the maximum regenerative torque When a state in which the actual deceleration is equal to or less than the target deceleration occurs according to the comparison result of the comparison unit, the traveling mode is such that the engine and the motor cooperate during the next deceleration after the completion of the current deceleration. A hybrid vehicle having a regenerative control unit that uses both the engine brake of the engine and the regenerative torque of the electric motor as a braking force has been proposed. For example, see Patent Document 1).

  However, this hybrid vehicle has a traveling form in which the engine and the motor cooperate in the next deceleration when the deceleration during the traveling by the electric motor alone is insufficient with the regenerative torque of the electric motor alone. Therefore, at the time of deceleration during traveling by the initial electric motor alone, the vehicle is decelerated only by insufficient regenerative torque of the electric motor, so that there is a problem that a braking torque of the hybrid vehicle cannot be sufficiently secured.

  In particular, trucks, buses, etc. are heavier than passenger cars, and the mechanical brake capacity, such as drum brakes, is relatively small compared to this weight. It is necessary to generate a braking torque larger than the braking torque. Therefore, auxiliary brakes such as exhaust brakes and retarders are equipped.

Japanese Patent No. 4988046

  Therefore, the present inventor aims to provide a hybrid vehicle and a control method thereof that can sufficiently secure a braking torque when the hybrid vehicle is decelerated while using the braking energy as charging energy. While the target required braking torque required for deceleration can be applied only by the regenerative torque generated by generating power with the motor generator, only the regenerative torque of the motor generator is set, and the target required braking torque is set. However, when the maximum value of the regenerative torque of the motor generator is exceeded, the braking torque by the engine brake of the internal combustion engine is added to the regenerative torque of the motor generator, and further, the target required braking torque is equal to the regenerative torque of the motor generator. If the sum of the maximum value and the maximum braking torque by the engine brake is exceeded, the regenerative torque of the motor generator and the engine The braking torque due rake was considered that the braking control operation by adding the braking torque due to the exhaust brake.

  However, in this case, the braking torque by the engine brake and the braking torque by the exhaust brake cannot be gradually increased, and a certain amount of braking torque is generated. Therefore, the engine brake is simply set to the maximum value of the regenerative torque. If the braking torque due to or the braking torque due to the exhaust brake is added, the target required braking torque will be exceeded. Therefore, in order to make the entire braking torque coincide with the target required braking torque, it is necessary to reduce the regenerative torque on the motor generator side by an amount exceeding the target required braking torque, and the regenerative energy is reduced accordingly. The problem of end.

  On the other hand, a compression release brake called a Jake brake is used in a diesel engine or the like as an assisting brake torque of a large vehicle. In this compression release brake, the compression of air in the cylinder is released by opening the exhaust valve without injecting fuel when the piston reaches near the top dead center in the compression stroke of the diesel engine. Unlike the brake, the braking torque can be adjusted by adjusting and controlling the timing and degree of opening of the exhaust valve.

  The present invention has been made in view of the above, and an object of the present invention is to provide a hybrid vehicle including a hybrid system having a function of using both an internal combustion engine and a motor generator as a driving source for traveling the vehicle. It is an object of the present invention to provide a hybrid vehicle and a control method therefor that can sufficiently secure a braking torque when the hybrid vehicle is decelerated while using braking energy as charging energy to the maximum.

In order to achieve the above object, a hybrid vehicle of the present invention is a hybrid vehicle having a hybrid system having a function of using both an internal combustion engine and a motor generator as a driving source for driving the vehicle, and controls the hybrid system. A control device that performs a first determination line indicating the maximum value of the braking torque of the motor generator based on the number of revolutions, and the braking torque of the compression release brake of the internal combustion engine is added to the braking torque of the first determination line. A second determination line indicating a braking torque obtained by adding the value, and a braking torque obtained by adding a maximum value of the braking torque of the exhaust brake provided in the exhaust passage connected to the internal combustion engine to the braking torque of the second determination line. 3 previously provided with a brake control data having a determined line, the target braking torque demand required to decelerate the hybrid vehicle, and the first judgment line In the first determination region between the first and second motors, the first braking control operation is performed in which the braking torque is applied only by the regenerative torque generated by the motor generator, and the target required braking torque is When in the second determination region between the determination line and the second determination line , the braking torque is given by the regenerative torque generated by the power generation by the motor generator and the braking torque by the compression release brake of the internal combustion engine, A second braking control operation for adjusting a braking torque by a compression release brake of the internal combustion engine in accordance with a magnitude of the target required braking torque so that a regenerative torque generated by generating power with the motor generator becomes a maximum value ; Done
When the target required braking torque is in a third determination region between the second determination line and the third determination line, the regenerative torque generated by power generation by the motor generator, the compression release brake of the internal combustion engine In accordance with the magnitude of the target required braking torque, the braking torque is given by the braking torque generated by the engine and the braking torque generated by the operation of the exhaust brake, and the regenerative torque generated by generating power by the motor generator is maximized. A third braking control operation for adjusting a braking torque by the compression release brake of the internal combustion engine is performed .

  This braking control data is expressed by map data (deceleration cooperative control map), a function based on the number of revolutions, etc., and this number of revolutions is the number of revolutions of the axle or wheels of the hybrid vehicle, The rotational speed of the motor generator and the rotational speed of the internal combustion engine, and these rotational speeds are closely related to each other. What is necessary is just to select and use a rotation speed.

  This compression release brake is a mechanism that opens the exhaust valve without injecting fuel when the piston reaches near the top dead center during the compression stroke of the engine, and exhausts when the piston reaches near the top dead center. By opening the valve and letting the compressed air escape to the exhaust passage, the pressure energy is released and more energy loss is generated. Furthermore, if the exhaust valve is closed after the piston has passed through the top dead center, there is no fuel combustion, so the pressure in the cylinder decreases as the piston descends, making it resistant to piston lowering and crankshaft rotation. . As a result, braking torque is generated.

  According to this configuration, when the target required braking torque can be ensured only by the regenerative torque of the motor generator, the regenerative torque of the motor generator is generated in the first braking control operation, and power is generated by the regenerative control of the motor generator. By charging the battery with electricity, it is possible to sufficiently secure the braking torque when the hybrid vehicle is decelerated while using the braking energy as the charging energy. Further, when the target required braking torque cannot be ensured only by the regenerative torque of the motor generator, the braking energy is obtained by adding the braking torque by the compression release brake of the internal combustion engine to the regenerative torque of the motor generator in the second braking control operation. The braking torque at the time of deceleration of the hybrid vehicle can be sufficiently ensured while maximally utilizing as the charging energy.

  In this case, unlike the engine brake, the compression release brake can adjust the braking torque by adjusting and controlling the timing and degree of opening of the exhaust valve, so that the regenerative torque by the motor generator is maximized. By adjusting the braking torque by the compression release brake so that the entire braking torque matches the target required braking torque, the regenerative energy can be utilized to the maximum by the motor generator.

The braking torque generated by the operation of the exhaust brake here means that the exhaust pressure is increased by closing the exhaust brake valve provided in the middle of the exhaust passage, and the pumping loss is increased. Is a braking torque obtained by increasing.

  According to this configuration, when the target required braking torque cannot be ensured even if the braking torque by the compression release brake of the internal combustion engine is added to the regenerative torque of the motor generator, the regenerative torque of the motor generator and the By adding the braking torque by the operation of the exhaust brake in addition to the braking torque by the compression release brake of the internal combustion engine, the target required braking torque can be sufficiently ensured while using the braking energy as the charging energy.

And a hybrid vehicle control method for achieving the above object is a hybrid vehicle control method including a hybrid system having a function of using both an internal combustion engine and a motor generator as a drive source for running the vehicle. A first determination line indicating the maximum value of the braking torque of the motor generator based on the number of revolutions, and a braking obtained by adding the maximum value of the braking torque by the compression release brake of the internal combustion engine to the braking torque of the first determination line A second determination line indicating torque, and a third determination line indicating a braking torque obtained by adding a maximum value of the braking torque of an exhaust brake provided in an exhaust passage connected to the internal combustion engine to the braking torque of the second determination line Using the braking control data, a target required braking torque required for decelerating the hybrid vehicle is in a first determination region between the first determination line and zero. When a first braking control operation is performed in which braking torque is applied only by regenerative torque generated by generating power with the motor generator, the target required braking torque is between the first determination line and the second determination line. When in the second determination region, the regenerative torque generated by the motor generator and the braking torque generated by the compression release brake of the internal combustion engine are applied, and the regenerative power generated by the motor generator is generated. A second braking control operation is performed in which the braking torque by the compression release brake of the internal combustion engine is adjusted according to the magnitude of the target required braking torque so that the torque becomes the maximum value, and the target required braking torque is 2 in the third determination region between the determination line and the third determination line, the regenerative torque generated by the power generation by the motor generator, the braking torque by the compression release brake of the internal combustion engine The internal combustion engine according to the magnitude of the target required braking torque so that the regenerative torque generated by generating electric power with the motor generator becomes a maximum value. A third braking control operation for adjusting a braking torque by the compression release brake of the engine is performed .

  According to this method, even when the target required braking torque cannot be ensured only by the regenerative torque of the motor generator, the braking torque is increased by adding the braking torque by the compression release brake of the internal combustion engine to the regenerative torque of the motor generator. The braking torque at the time of deceleration of the hybrid vehicle can be sufficiently secured while maximally using energy as charging energy.

In addition, even if the braking torque by the compression release brake of the internal combustion engine is added to the regenerative torque of the motor generator , even if the target required braking torque cannot be ensured, further by adding the braking torque by the operation of the exhaust brake, The target required braking torque can be sufficiently ensured while maximally using the braking energy as the charging energy.

  According to the hybrid vehicle and its control method of the present invention, when the target required braking torque at the time of deceleration of the vehicle can be ensured only by the regenerative torque of the motor generator, the target required braking torque is obtained by performing the regeneration control with the motor generator. The electricity generated by this regenerative control can be charged to the battery. If the target required braking torque cannot be ensured only with the regenerative torque of the motor generator, the braking torque generated by the compression release brake of the internal combustion engine is added to the regenerative torque of the motor generator. In addition, by generating the regenerative torque at the maximum, a part of the braking energy can be utilized to the maximum as the charging energy.

  Further, when the target required braking torque is insufficient even when the braking torque by the compression release brake of the internal combustion engine is added to the braking torque of the motor generator, the braking torque by the operation of the exhaust brake is further generated. The braking torque that can be generated during deceleration of the hybrid vehicle can be further increased.

It is a figure which shows an example of the control flow regarding the control method of the hybrid vehicle of embodiment of this invention. It is a figure for explanation of target demand braking torque. It is a figure which shows an example of the map for deceleration control typically. It is a figure for demonstrating the selection method of deceleration control. It is a figure which shows typically the range of the regenerative torque which can be converted into regenerative energy. It is a figure which shows the structure of the hybrid vehicle of embodiment of this invention. It is a figure which shows the driving | running state of 1st deceleration control driving | operation. It is a figure which shows the driving | running state of 2nd deceleration control driving | operation. It is a figure which shows the driving | running state of 3rd deceleration control driving | operation.

  Hereinafter, a hybrid vehicle and a control method thereof according to an embodiment of the present invention will be described. As shown in FIG. 6, a hybrid vehicle (HEV: hereinafter referred to as a vehicle) 1 according to this embodiment uses both an engine (internal combustion engine) 10 and a motor generator (traveling motor / generator) 20 for traveling. This is a parallel hybrid vehicle that uses a power source.

  Here, a parallel hybrid vehicle will be described as an example. However, the parallel hybrid vehicle is not necessarily used, and a function capable of using both the engine 10 and the motor generator 20 as a power source for traveling is used. Any hybrid vehicle may be used.

  First, the hybrid vehicle 1 according to the embodiment of the present invention will be described. As shown in FIG. 6, the power of the engine 10 is transmitted to the transmission 30 via the torque converter 14 connected to the engine 10 and the engine clutch 15 in the connected state, and further from the transmission 30 via the propeller shaft 31. It is transmitted to the differential gear 32 and transmitted from the differential gear 32 to the wheel 34 via the drive shaft 33. Thereby, the power of the engine 10 is transmitted to the wheels 34, and the vehicle 1 travels.

  On the other hand, regarding the power of the motor generator 20, the power charged (charged) in the battery 22 is supplied to the motor generator 20 via the inverter 21, and the motor generator 20 is driven by this power to generate power. The power of the motor generator 20 is transmitted to the transmission 30 through the connected motor generator clutch 23, and further transmitted from the transmission 30 to the differential gear 32 through the propeller shaft 31, and is driven from the differential gear 32. It is transmitted to the wheel 34 via the shaft 33. Thereby, the motive power of the motor generator 20 is transmitted to the wheels 34 and the vehicle 1 travels.

  Then, transmission and disconnection of the power of the engine 10 to the wheels 34 is performed by switching operation of the engine clutch 15 and switching of the engine clutch 15, and the motor generator is switched by switching operation of the clutch 23 of the motor generator and switching of the motor clutch. The transmission of the power of 20 to the wheel 34 is cut off, and the transmission of the power of the engine 10 or the motor generator 20 can be switched appropriately, and the engine clutch 15 and the motor generator clutch 23 are necessarily provided. There is no need.

  In this engine 10, power is generated by burning fuel in the engine 10 and moving a piston. The exhaust gas G generated by this combustion includes NOx (nitrogen oxide), PM (Particulate Matter: fine particles). In this case, it is not preferable from the viewpoint of environmental pollution if it is released as it is without any treatment. Therefore, an exhaust gas purification device 13 having an oxidation catalyst device, a NOx reduction catalyst device, a PM trapping filter device, and the like is disposed in the exhaust passage 11, and the exhaust gas purification device 13 allows NOx in the exhaust gas G, PM etc. are purified. The purified exhaust gas Gc is released into the atmosphere via a muffler (not shown) or the like.

  As a device for generating the braking torque (braking force) of the vehicle 1, a mechanical service brake such as a drum brake or a disc brake provided on the wheel 34 that is operated by depressing a brake pedal is provided. However, in a large vehicle such as a truck, the braking torque of a mechanical service brake such as a hydraulic type, a pneumatic type, a combined air-hydraulic type or the like is relatively small compared to the weight of the vehicle 1. As an auxiliary brake, an exhaust brake valve (shutter valve) 12 is provided in the exhaust passage 11.

  The compression release brake is a mechanism that opens the exhaust valve without injecting fuel when the piston reaches near the top dead center in the compression stroke of the engine 10. In the compression stroke, the kinetic energy of the engine 10 is converted into pressure energy and compression heat due to the compression of air in the cylinder. When the piston passes the top dead center while keeping the cylinder airtight, the compressed air expands, The pressure energy of air is converted back into kinetic energy, but when the piston reaches the top dead center, the exhaust valve is opened to release the compressed air to the exhaust passage and release the pressure energy. More energy loss. Furthermore, if the exhaust valve is closed after the piston has passed through the top dead center, there is no fuel combustion, so the pressure in the cylinder decreases as the piston descends, making it resistant to piston lowering and crankshaft rotation. . As a result, braking torque is generated.

  On the other hand, the exhaust brake closes the exhaust brake valve 12 and increases the exhaust pressure in the cylinder of the engine 10, thereby increasing the pumping loss and increasing the rotational resistance of the internal combustion engine. Can be obtained. In FIG. 6, the exhaust brake valve 12 is disposed upstream of the exhaust gas purification device 13 in the exhaust passage 11, but the exhaust brake valve 12 is disposed downstream of the exhaust gas purification device 13. However, the same braking torque can be generated.

  And the control apparatus 40 for controlling the engine 10, the motor generator 20, the hybrid system, and the vehicle 1 is provided. By this control apparatus 40, the overall control of the engine 10 including the compression release brake control, the inverter 21 is provided. The overall control of the motor generator 20 by the control, the overall control of the hybrid system including the connection / disconnection control of the engine clutch 15 and the connection / disconnection control of the motor generator clutch 23, and the opening / closing control of the exhaust brake valve 12 of the vehicle 1 Perform general control and so on.

  Next, a hybrid vehicle control method according to an embodiment of the present invention will be described with reference to FIGS. The control flow of FIG. 1 is repeatedly executed by the advanced control flow when the vehicle 1 is started. When the vehicle 1 is stopped, the control flow returns to the advanced control flow by interruption, and the advanced control flow. It is shown as a control flow that stops with the stop.

  When this control flow is called by the advanced control flow and starts, it is determined in step S11 whether or not a braking torque for decelerating the vehicle 1 is necessary. In this determination, an accelerator pedal depression amount, a brake pedal depression amount, or the like is used. For example, when the accelerator pedal is released and the amount of depression becomes zero or the brake pedal is depressed, the vehicle 1 is instructed to decelerate, and it is determined that braking torque is required.

  If it is determined in step S11 that braking torque is not required (NO), after a preset first time (time related to the determination interval in step S11) has elapsed, the process returns to step S11. If it is determined in step S11 that braking torque is required (YES), the process proceeds to the next step S12.

  In step S12, a target required braking torque Tt is calculated. As shown in FIG. 2, the target required braking torque Tt varies depending on the depression amount (α, β, γ) of the brake pedal and the vehicle speed, in other words, the propeller shaft 31, the drive shaft 33, the wheels 34, and the like. As the rotational speed of the horizontal axis shown in FIG. 2, the rotational speed of the propeller shaft 31, the drive shaft 33, or the wheel 34 of the vehicle, or these rotational speeds are closely related to each other. Of the number of rotations of the output shaft of the transmission 30, the number of rotations of the motor generator 20, or the number of rotations of the internal combustion engine 10, a representative number of rotations is selected and used. Here, the rotational speed N of the internal combustion engine 10 is used.

  When the driver (driver) needs to decelerate the vehicle 1, the driver releases the accelerator pedal and depresses the brake pedal. The required target torque Tt1 is calculated.

  As shown in FIG. 2, the required amount of torque Tt1 increases as the amount of depression increases, the absolute amount of torque on the required target torque Tt line Lt (Lα, Lβ, Lγ) based on the rotational speed N increases. The smaller the amount α, β, γ, the smaller the absolute amount of torque on the line Lt (Lα, Lβ, Lγ) of the required target torque Tt based on the rotational speed N. If the amount of depression of the accelerator pedal is the same, the required target torque Tt1 gradually decreases as the rotational speed N1 decreases.

  That is, the target required braking torque line Lt depends on the amount of depression α, β, γ of the brake pedal of the driver in addition to the rotational speed N of the internal combustion engine 10, so the target required braking torque line Lt It moves up and down according to the depression amounts α, β, γ. More specifically, when the brake pedal depression amounts α, β, γ are the second depression amount β larger than the first depression amount α, a larger target required braking torque Tt is required. This is the required braking torque line Lβ. Further, when the brake pedal depression amounts α, β, γ are the third depression amount γ larger than the second depression amount β, the target required braking torque Tt is further increased, and therefore the target required braking torque line Lγ. It becomes.

  And it corresponds to the actual brake pedal depression amount (for example, β) from the target required braking torque line (Lα, Lβ, Lγ, etc.) corresponding to the depression amount of the brake pedal (α, β, γ, etc.) by the driver. After the target required braking torque line Lβ to be selected is selected, the target required braking torque Tt1 corresponding to the rotational speed N1 of the internal combustion engine 10 is calculated on the selected target required braking torque line Lβ.

  In the next step S13, the target required braking torque Tt1 calculated in step S12 is the first determination region R1 and second determination region R2 of the “deceleration control map (deceleration control data)” M1 as shown in FIG. The third determination region R3 is determined.

  The “deceleration control map” M1 in FIG. 3 has the first determination line L1, the second determination line L2, and the third determination with the rotational speed N of the internal combustion engine 10 as the horizontal axis and the braking torque T as the vertical axis. It is the figure which set line L3. This “braking control data” M1 is set in advance based on experimental data of a running experiment and the like, and is incorporated in the control device 40.

  The first determination line L1 is a line indicating the maximum value T1max of the regenerative torque (braking torque) T1 of the motor generator 20 based on the rotation speed N. The second determination line L2 is a brake obtained by adding the maximum value T2max of the braking torque T2 by the compression release brake of the engine 10 to the maximum value T1max of the regenerative torque T1 of the motor generator 20 indicated by the first determination line L1. It is a line indicating the torque Ta (= T1max + T2max). Further, the third determination line L3 is a line indicating a braking torque Tb (= Ta + T3max = T1max + T2max + T3max) obtained by adding the maximum value T3max of the braking torque T3 due to the operation of the exhaust brake valve 12 of the engine 10 to the braking torque Ta.

  A region between the first determination line L1 and the horizontal axis L0 indicating zero braking torque is a first determination region R1, and a region between the first determination line L1 and the second determination line L2 is a second determination region R2. A region between the second determination line L2 and the third determination line L3 is defined as a third determination region R3.

  In the determination of step S13, when the target required braking torque Tt is in the first determination region R1 (for example, point C in FIG. 4; Ttc) between the first determination line L1 and the horizontal axis L0 indicating zero torque, Proceeding to step S14, as shown in FIG. 7, the first braking control operation for applying the braking torque T to the wheels 34 of the vehicle 1 is performed only by the regenerative torque T1 generated by the regenerative control of the motor generator 20. By performing the first braking control operation, the regenerative torque T1 (= Ttc) of the motor generator 20 is generated, and the electricity generated by the regenerative control of the motor generator 20 is charged in the battery 22 to thereby generate braking energy. The target required braking torque Tt when the vehicle 1 is decelerated can be sufficiently generated while using as charging energy.

  Further, when it is determined in step S13 that the target required braking torque Tt is in the second determination region R2 (eg, point B in FIG. 4; Ttb) between the first determination line L1 and the second determination line L2, step Proceeding to S15, as shown in FIG. 8, the maximum value T1max of the regenerative torque T1 generated by the motor generator 20 is generated, and the braking torque T2 generated by the compression release brake of the engine 10 is generated. A second braking control operation that generates Ttb is performed.

  By performing the second braking control operation, the braking torque T2 (= Ttb−T1max) due to the compression release brake of the engine 10 is added to the maximum value T1max of the regenerative torque T1 of the motor generator 20, and the braking energy is charged energy. As a result, it is possible to generate the target required braking torque Ttb when the vehicle 1 is decelerated and to secure the braking torque Ttb when the vehicle 1 is decelerated.

In this case, since the braking torque T2 by the compression release brake can be gradually increased, the braking torque T2 by the compression release brake (= Ttb −) is increased to the maximum value T1max of the regenerative torque T1 so as to become the target required braking torque Ttb. T1max). Therefore, the regenerative torque T1 on the motor generator 20 side can be set to the maximum value T1max, and the braking energy can be converted into regenerative energy in a state where the maximum regenerative torque is generated by the motor generator 20, and one of the braking energy can be converted. Can be used as much as the charging energy.

Further, when it is determined in step S13 that the target required braking torque Tt is in the third determination region R3 (for example, point A in FIG. 4; Tta) between the second determination line L2 and the third determination line L3, step Proceeding to S16, as shown in FIG. 9, in addition to the regenerative torque T1max generated by the motor generator 20 and the braking torque T2 generated by the operation of the compression release brake, the exhaust brake valve 12 is throttled (closed), and the exhaust brake valve The third braking control operation for generating the braking torque T3 by the operation of No. 12 is performed.

  Also in this case, the braking torque T3 due to the exhaust brake valve 12 cannot be gradually increased, and a certain amount of braking torque T3 is generated, but the braking torque T2 due to the compression release brake can be gradually increased. Therefore, the braking torque T2 (= Tta−T1max−T3) due to the compression release brake is added to the maximum value T1max of the regenerative torque T1 and the braking torque T3 due to the exhaust brake so that the target required braking torque Tta is obtained. Therefore, the regenerative torque T1 on the motor generator 20 side can be set to the maximum value T1max, and the braking energy can be converted into regenerative energy in a state where the maximum regenerative torque is generated by the motor generator 20, and one of the braking energy can be converted. Can be used as much as the charging energy.

  By performing this third braking control operation, the target required braking torque Tta at the time of deceleration of the vehicle 1 is generated while adding the braking torque T3 (= Tta−T1max−T2) and using the braking energy as the charging energy. Thus, the braking torque Tta when the vehicle 1 is decelerated can be secured.

In steps S14, S15, and S16, the first, second, and third braking control operations are performed, and after a preset second time (time related to the control interval) has elapsed, the process returns to step S11. Steps S11 to S14 to S11, S11 to S15 to S11, and S11 to S16 to S11 are repeated. Then, when the operation of the vehicle 1 is stopped, the vehicle 1 returns by interruption and returns to the advanced control flow, and stops when the advanced control flow stops.

  In actual control, when a deceleration request is issued, a target required braking torque line Lβ corresponding to the brake pedal depression amount (for example, β) by the driver is selected with reference to FIG. 3, and is shown in FIG. Thus, when the rotation speed N at that time is, for example, the rotation speed is Na, the target required torque Tt is calculated as Tta at the point A, and is determined to be in the third determination region R3 and the third braking control operation is performed. As a result, the rotational speed N decreases.

  If the amount of depression of the brake pedal (for example, β) does not change as it is, the target required torque Tt moves on the target required braking torque line Lβ to the left side of FIG. 4 and enters the second determination region R2. The braking control operation is performed, and further moves on the target required braking torque line Lβ to the left side of FIG. 4 and enters the first determination region R1. In the first determination region R1, the first braking control operation is performed.

  FIG. 5 schematically shows a recovery torque range (cross-hatched portion) that can be used as a recovery energy source when moving on the target required braking torque line Lβ. When the compression release brake is used, the recovered torque can be utilized to the maximum, so the range of the recovered torque that can be used as a recovered energy source (cross-hatched portion) changes along the first determination line L1. .

  According to the hybrid vehicle having the above configuration and the control method thereof, when it is determined that the target required braking torque Tt when the vehicle 1 is decelerated can be secured only by the regenerative torque (braking torque T1) of the motor generator 20, By performing regenerative control only with the generator 20, the target required braking torque Tt can be secured, and the battery 22 can be charged with electricity generated by this regenerative control. Further, when it is determined that the target required braking torque Tt when the vehicle 1 is decelerated cannot be secured only by the regenerative torque T1 of the motor generator 20, the braking torque T1 of the motor generator 20 is determined by the compression release brake of the engine 10. Since the target required braking torque Tt when the vehicle 1 is decelerated is secured by adding the braking torque T2, the vehicle 1 is decelerated while utilizing a part of the braking energy as the charging energy by the generation of the maximum regenerative torque. Sufficient braking torque can be secured.

  Further, if it is determined that the target required braking torque Tt is insufficient even if the braking torque T2 due to the compression release brake of the engine 10 is added to the braking torque T1 of the motor generator 20, in addition to these starting torques T1 and T2 The braking torque T3 generated by the operation of the exhaust brake valve 12 can be generated to generate the target required braking torque Tt that is required when the vehicle 1 is decelerated. In addition, by generating the maximum regenerative torque, a part of the braking energy can be utilized to the maximum as charging energy.

1 Vehicle (Hybrid vehicle: HEV)
10 Engine (Internal combustion engine)
11 Exhaust passage 12 Exhaust brake valve 13 Exhaust gas purifier 14 Torque converter 15 Engine clutch 16 Crankshaft 20 Motor generator 21 Inverter 22 Battery 23 Motor generator clutch 30 Transmission 31 Propeller shaft 32 Differential gear 33 Drive shaft 34 Wheel 40 Control unit (ECU)
L0 horizontal axis (braking torque = zero)
L1 First determination line L2 Second determination line L3 Third determination line M1 Deceleration control map (deceleration control data)
T1 Regenerative torque by motor generator T1max Maximum value of regenerative torque by motor generator T2 Maximum braking torque by compression release brake T2max Maximum value of braking torque by compression release brake T3 Maximum braking torque by exhaust brake T3max Maximum value of braking torque by exhaust brake Tt , Ta, Tb, Tc Target required braking torque

Claims (2)

In a hybrid vehicle including a hybrid system having a function of using both an internal combustion engine and a motor generator as a drive source for traveling the vehicle,
A control device for controlling the hybrid system includes a first determination line indicating a maximum value of the braking torque of the motor generator based on the number of revolutions, and a compression release brake of the internal combustion engine based on the braking torque of the first determination line. A second determination line indicating the braking torque obtained by adding the maximum value of the braking torque by the engine, and the maximum value of the braking torque of the exhaust brake provided in the exhaust passage connected to the internal combustion engine is added to the braking torque of the second determination line Preliminarily provided with braking control data provided with a third determination line indicating the braking torque ,
When the target required braking torque required for decelerating the hybrid vehicle is in the first determination region between the first determination line and zero, the regenerative torque generated by generating power with the motor generator The first braking control operation that gives the braking torque only is performed,
When the target required braking torque is in a second determination region between the first determination line and the second determination line, the regenerative torque generated by the power generation by the motor generator and the compression release brake of the internal combustion engine Braking by the compression release brake of the internal combustion engine in accordance with the magnitude of the target required braking torque so that the braking torque is given by the braking torque generated by the motor generator and the regenerative torque generated by power generation by the motor generator is maximized. Perform the second braking control operation to adjust the torque ,
When the target required braking torque is in a third determination region between the second determination line and the third determination line, the regenerative torque generated by power generation by the motor generator, the compression release brake of the internal combustion engine In accordance with the magnitude of the target required braking torque, the braking torque is given by the braking torque generated by the engine and the braking torque generated by the operation of the exhaust brake, and the regenerative torque generated by generating power by the motor generator is maximized. A hybrid vehicle configured to perform a third braking control operation for adjusting a braking torque by a compression release brake of the internal combustion engine . In a control method for a hybrid vehicle including a hybrid system having a function of using both an internal combustion engine and a motor generator as a driving source for traveling of the vehicle,
A first determination line indicating the maximum value of the braking torque of the motor generator based on the number of revolutions, and a braking obtained by adding the maximum value of the braking torque by the compression release brake of the internal combustion engine to the braking torque of the first determination line A second determination line indicating torque, and a third determination line indicating a braking torque obtained by adding a maximum value of the braking torque of an exhaust brake provided in an exhaust passage connected to the internal combustion engine to the braking torque of the second determination line Using the braking control data
When the target required braking torque required for decelerating the hybrid vehicle is in the first determination region between the first determination line and zero, the regenerative torque generated by generating power with the motor generator The first braking control operation that gives the braking torque only is performed,
When the target required braking torque is in a second determination region between the first determination line and the second determination line, the regenerative torque generated by the power generation by the motor generator and the compression release brake of the internal combustion engine Braking by the compression release brake of the internal combustion engine in accordance with the magnitude of the target required braking torque so that the braking torque is given by the braking torque generated by the motor generator and the regenerative torque generated by power generation by the motor generator is maximized. Perform the second braking control operation to adjust the torque ,
When the target required braking torque is in a third determination region between the second determination line and the third determination line, the regenerative torque generated by power generation by the motor generator, the compression release brake of the internal combustion engine In accordance with the magnitude of the target required braking torque, the braking torque is given by the braking torque generated by the engine and the braking torque generated by the operation of the exhaust brake, and the regenerative torque generated by generating power by the motor generator is maximized. A control method for a hybrid vehicle, wherein a third braking control operation for adjusting a braking torque by a compression release brake of the internal combustion engine is performed .

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