JP2005240580A - Hybrid vehicle and its control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress the shortage of torque assistance to a request for acceleration even if the charged amount of a battery lowers to a specified value or below. <P>SOLUTION: This hybrid vehicle 10 comprises an engine 11, a step type transmission 12, a motor generator 17, an electric supercharging system formed of a motor-assisted turbo-supercharger, an assist amount calculation means calculating a torque assist amount based on a deviation between a driver requesting torque and an actual engine torque, a charged amount detection means detecting the charged amount SOC of a battery 20, and a torque assist control means assisting the torque assist amount calculated by the assist amount calculation means by using one or both of a motor generator 17 and the electric supercharging system according to the detected charged amount SOC. When the charged amount SOC is small, torque assist is performed by the electric supercharging system, and when the charged amount SOC is large, the torque assist is performed by a motor generator. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a hybrid vehicle and a control method therefor, and more specifically, a hybrid vehicle capable of suppressing a shortage of torque assist in response to an acceleration request even when the amount of charge of a battery is reduced to a predetermined value or less. Regarding the method.

  A hybrid vehicle has been proposed in which the engine output torque deficiency caused by the turbo lag is compensated by the output torque of the electric motor to improve the response to depression of the accelerator pedal (see, for example, Patent Document 1). The hybrid vehicle is controlled so that the output torque of the electric motor is increased during sudden acceleration and the output torque of the electric motor is decreased during slow acceleration. Further, when the stored amount of the battery falls below a predetermined value, the output torque of the electric motor is gradually reduced, thereby suppressing the sudden reduction of the output torque of the electric motor when the battery is discharged.

JP-A-11-148388

  However, since the torque assist by the electric motor consumes a large amount of power, the output torque of the electric motor suddenly decreases when the battery is discharged by gradually decreasing the output torque of the electric motor when the amount of storage of the battery drops below a predetermined value. However, there is a problem in that insufficient torque assist for the acceleration request may occur.

  The present invention has been made in view of the above, and provides a hybrid vehicle capable of suppressing a shortage of torque assist in response to an acceleration request even when the amount of charge of a battery is reduced to a predetermined value or less. With the goal.

  Another object of the present invention is to provide a control method for a hybrid vehicle that can suppress a shortage of torque assist in response to an acceleration request even when the amount of power stored in the battery drops below a predetermined value.

  In order to solve the above-described problems and achieve the object, a hybrid vehicle according to a first aspect of the present invention includes an engine as a travel drive source, a stepped transmission, the power generation by the engine output or the battery power. Based on a motor generator that assists engine output, an electric supercharging system that consists of a motor-assisted turbocharger or a turbocharger combined with a motor compressor, and the deviation between the driver required torque and the actual engine torque Assist amount calculating means for calculating a torque assist amount, storage amount detecting means for detecting or estimating the storage amount of the battery, and torque assist amount calculated by the assist amount calculating means detected by the storage amount detecting means or According to the estimated battery storage amount, the motor generator and the Using one or both of the dynamic supercharging system is characterized in that a torque assist control means for assisting.

  Therefore, according to the present invention, it is possible to suppress the battery charge amount from being excessively reduced, and to suppress the shortage of torque assist for the acceleration request even when the battery charge amount is reduced to a predetermined value or less. be able to.

  According to a second aspect of the present invention, there is provided a hybrid vehicle control method comprising: an engine as a travel drive source; a stepped transmission; a motor generator that assists the engine output by power generation or battery power by the engine output; , An electric supercharging system comprising a motor-assisted turbocharger or a combination of a turbocharger and a motor compressor, and an assist amount calculation that calculates a torque assist amount based on a deviation between a driver request torque and an actual engine torque Means for detecting or estimating the storage amount of the battery, and the torque assist amount calculated by the assist amount calculation unit according to the battery storage amount detected or estimated by the storage amount detection unit. One of the motor generator and the electric supercharging system Or a hybrid vehicle control method comprising torque assist control means for assisting using both, and when the battery charge amount is small, the electric supercharging system assists in torque assist while the battery charge amount is When there are many, torque assist is performed by the motor generator.

  Therefore, according to the present invention, it is possible to suppress the battery charge amount from being excessively reduced, and to suppress the shortage of torque assist for the acceleration request even when the battery charge amount is reduced to a predetermined value or less. be able to.

  According to a third aspect of the present invention, there is provided a hybrid vehicle control method comprising: an engine as a travel drive source; a stepped transmission; a motor generator that assists the engine output by power generation or battery power by the engine output; , An electric supercharging system comprising a motor assist turbocharger or a turbocharger combined with a motor compressor, and an assist amount calculation for calculating a torque assist amount based on a deviation between a driver request torque and an actual engine torque Means for detecting or estimating the storage amount of the battery, and the torque assist amount calculated by the assist amount calculation unit according to the battery storage amount detected or estimated by the storage amount detection unit. One of the motor generator and the electric supercharging system Alternatively, a hybrid vehicle control method comprising torque assist control means for assisting using both, and when the battery charge amount is less than a first predetermined value, torque assist is performed by the electric supercharging system. When the battery storage amount is equal to or greater than a second predetermined value that is greater than the first predetermined value, torque is assisted by the motor generator so that the battery storage amount is equal to the first predetermined value and the second predetermined value. When it is between the predetermined values, the electric supercharging system and the motor generator are used in combination for torque assist.

  According to the present invention, when there is a torque assist request, if the battery charge amount is smaller than the first predetermined value, the supercharging pressure is increased and the fuel injection amount is increased by the electric supercharging system. The engine torque increases and torque assist is provided. In this case, since the electric power consumption of the electric supercharging system is small, the amount of decrease in the battery charge amount is small. Therefore, it is possible to suppress an excessive decrease in the battery storage amount.

  Further, when the battery storage amount is equal to or greater than the second predetermined value, even if torque assist is performed by a motor generator having a large power consumption, there is no possibility that a problem due to excessive reduction of the battery storage amount occurs. Therefore, the torque assist request can be satisfied, and since the motor generator is used, the torque assist can be efficiently performed without increasing the fuel consumption, and the fuel consumption can be improved.

  In addition, when the battery storage amount is between the first predetermined value and the second predetermined value, it is possible to suppress an excessive decrease in the battery storage amount by using the electric supercharging system and the motor generator together. However, appropriate torque assist can be realized.

  According to a fourth aspect of the present invention, there is provided a method for controlling a hybrid vehicle according to the third aspect of the present invention, wherein in the region where the electric supercharging system and the motor generator are used together for torque assist, both torque assists are provided. The amount sharing ratio is changed based on the supercharging efficiency map.

  Therefore, according to the present invention, it is possible to improve the supercharging efficiency in the region where the electric supercharging system and the motor generator are used together, and to realize efficient torque assist.

  According to a fifth aspect of the present invention, there is provided a hybrid vehicle control method according to the fourth aspect of the present invention, wherein the electric vehicle supercharging system and the motor generator are used in combination for torque assist, and the torque In a region where the assist amount is a minute amount equal to or less than a predetermined value, the share ratio of the torque assist amount is set to be steeply zero.

  Therefore, according to the present invention, it is possible to suppress the deterioration of efficiency even in the minute torque assist region where the efficiency is deteriorated.

  According to the hybrid vehicle of the present invention (Claim 1), it is possible to suppress the battery storage amount from being excessively reduced, and to request acceleration even when the battery storage amount has decreased below a predetermined value. Insufficient torque assist can be suppressed.

  Further, according to the hybrid vehicle control method of the present invention (Claim 2), it is possible to suppress an excessive decrease in the battery charge amount and to reduce the battery charge amount to a predetermined value or less. However, it is possible to suppress a shortage of torque assist for the acceleration request.

  Moreover, according to the hybrid vehicle control method (claim 3) of the present invention, it is possible to achieve appropriate torque assist while suppressing an excessive decrease in the battery charge amount.

  According to the hybrid vehicle control method (claim 4) of the present invention, the supercharging efficiency can be improved and efficient torque assist can be realized.

  In addition, according to the hybrid vehicle control method of the present invention (Claim 5), it is possible to suppress the deterioration of efficiency even in the minute torque assist region where the efficiency is deteriorated.

  Below, the case where this invention is applied to a diesel hybrid vehicle is demonstrated in detail, referring drawings. Note that the present invention is not limited to the embodiments.

  First, a schematic configuration of a diesel hybrid vehicle that is a front wheel drive vehicle (FF vehicle) will be described with reference to FIGS. 1 and 2. Here, FIG. 1 is a schematic diagram illustrating a schematic configuration of the diesel hybrid vehicle according to the first embodiment of the present invention, and FIG. 2 is a schematic diagram illustrating an electric supercharging system using a motor-assisted turbocharger.

  As shown in FIG. 1, the diesel hybrid vehicle 10 is provided with a diesel engine 11 as a travel drive source at the front of the vehicle. As shown in FIG. 2, the diesel engine 11 has a fuel injection amount controlled by a common rail fuel injection system 11a. The intake passage 21 is provided with an air flow meter 22 for detecting the intake air amount and a throttle valve 24 for adjusting the intake air amount.

  The diesel engine 11 also includes a turbocharger 26 that assists the engine torque by driving the coaxial compressor 26a by rotating the turbine 26b using the exhaust gas pressure to increase the intake air amount. .

  The turbocharger 26 includes an electric motor (not shown), and is configured as a motor-assisted turbocharger (electric supercharging system) so that the compressor 26a can be driven by the electric motor when necessary. The electric power of this electric supercharging system is supplied from a battery 20 described later. An intercooler 28 is provided in the intake passage 21 between the turbocharger 26 and the intake manifold 21a for cooling the intake air that has been supercharged and heated.

  In addition, although the said electric supercharging system was demonstrated as what comprises the motor assist turbocharger 26, it is not limited to this. For example, as shown in FIG. 3, an electric supercharging system is configured by combining a motor compressor 23 that compresses intake air by being driven by an electric motor with a normal turbocharger 26 that is driven only by exhaust pressure. May be. The electric power of the motor compressor 23 is supplied from a battery 20 described later. Here, FIG. 3 is a schematic diagram showing another electric supercharging system in which a turbocharger is combined with a motor compressor.

  In addition, as shown in FIG. 2, in the exhaust passage 30 of the diesel engine 11, a particulate filter carrying an NOx storage reduction catalyst for purifying particulate matter and nitrogen oxides (NOx) in the exhaust gas. 33 is provided. The diesel engine 11 includes a known variable valve timing mechanism (not shown) that variably controls the valve opening / closing operation timing.

  The diesel engine 11 also includes an exhaust gas recirculation device (hereinafter referred to as an EGR device) 35 that recirculates a part of the exhaust gas to the intake system. An EGR cooler 37 and an EGR valve 38 are provided in the EGR passage 36 of the EGR device 35. The fresh air whose flow rate is adjusted by the throttle valve 24 and the EGR gas that has passed through the EGR cooler 37 and the EGR valve 38 are compressed by the compressor 26a of the turbocharger 26 and supplied to the diesel engine 11 via the intercooler 28. Further, the exhaust gas discharged from the diesel engine 11 drives the turbine 26b of the turbocharger 26, and a part of the exhaust gas that has passed through the particulate filter 33 passes through the EGR cooler 37 and the EGR valve 38 in the EGR passage 36. After that, it is returned to the intake system.

  In the electric supercharging system shown in FIG. 2 and FIG. 3, the EGR gas from the EGR device 35 is introduced upstream of the compressor 26a. However, the present invention is not limited to this. For example, as shown in FIG. 4, an electric turbocharging system is configured by adding the motor compressor 23 to a normal turbocharger 26 that is driven only by exhaust pressure, and at the upstream of the turbine 26 b of the turbocharger 26. The EGR device 35 may be configured to recirculate EGR gas from the exhaust manifold 30a to the intake manifold 21a downstream of the compressor 26a of the turbocharger 26. In the EGR passage 36 of the EGR device 35, an EGR cooler catalyst 39, an EGR cooler 37, and an EGR valve 38 are provided in order from the exhaust manifold 30a side to the intake manifold 21a side. Here, FIG. 4 is a schematic diagram showing another electric supercharging system.

  Further, as shown in FIG. 1, the driving force generated by the diesel engine 11 is driven mainly through a stepped transmission (hereinafter referred to as MMT (multimode manual transmission)) 12 and a drive shaft 14 that can be automatically shifted. It is transmitted to the front wheel 13 as a wheel. The MMT 12 electrically and automatically controls a gear shift operation by an actuator in accordance with a traveling state. In addition, the rear wheel (not shown) has a configuration that is merely driven by the front wheel 13 that is a driving wheel.

  The diesel engine 11 is configured such that its fuel injection amount, intake air amount, and the like are controlled in order to output the requested engine torque commanded from the MMT 12. The required fuel injection amount of the diesel engine 11 is determined based on a map from the engine speed and the accelerator opening, for example, and fuel injection is executed.

  In addition, the diesel hybrid vehicle 10 is provided with a clutch 12a that performs contact / separation of power transmission between the diesel engine 11 and the MMT 12, so that the contact / separation operation is automatically and electrically controlled by an actuator according to the traveling state. It has become.

  Further, a motor generator (MG) 17 integrated with a drive system gear device (gear train) is connected to the drive shaft 14 provided with the differential gear 15. The motor generator 17 is connected to a battery 20 that is a chargeable / dischargeable secondary battery via an inverter 19, and includes a power running operation mode that functions as a motor that is a travel drive source, and a regenerative operation mode that functions as a generator. It is configured to be able to take two operating states.

  For example, the motor generator 17 receives power supplied from the battery 20 in the power running operation mode, and generates power for driving the drive shaft 14. In the regenerative operation mode, the motor generator 17 converts the driving force transmitted from the diesel engine 11 or the drive shaft 14 into electric power and charges the battery 20.

  Whether the motor generator 17 is operated in the power running operation mode or the regenerative operation mode is determined in consideration of the charged amount SOC (State of Charge) of the battery 20.

  The diesel hybrid vehicle 10 configured as described above is basically controlled as follows based on output information from various sensors by an electronic control unit (ECU) (not shown), and can travel in various states. The ECU calculates an assist amount calculation unit that calculates a torque assist amount based on a deviation between a driver request torque and an actual engine torque, and an accumulation amount detection unit that detects or estimates an accumulation amount SOC of the battery 20. A torque assist control means for assisting the torque assist amount using either or both of the motor generator 17 and the electric supercharging system according to the detected or estimated battery storage amount SOC is also provided.

  In a relatively low speed state in which the diesel hybrid vehicle 10 has started traveling, the vehicle travels (EV traveling) by powering the motor generator 17 while the diesel engine 11 is stopped. Then, when the diesel hybrid vehicle 10 reaches a predetermined speed or load after the start of traveling, the diesel engine 11 is cranked and started using the motor generator 17 and the operation is shifted to the operation using the diesel engine 11.

  During steady operation, the diesel engine 11 is normally operated so as to generate an output substantially equal to the required power of the drive shaft 14. At this time, almost all of the output of the diesel engine 11 is transmitted to the drive shaft 14.

  On the other hand, when the charged amount SOC of the battery 20 is reduced below a predetermined reference value, the diesel engine 11 is operated with an output exceeding the required power of the drive shaft 14, and a part of the surplus power is motor It is regenerated as electric power by the generator 17 and used for charging the battery 20.

  When the output torque of the diesel engine 11 is insufficient, as described later, one or both of the motor generator 17 and the motor-assisted turbocharger 26 that is the above-described electric supercharging system according to the storage amount SOC of the battery 20. Is used to assist the shortage of torque and ensure the necessary torque.

  The diesel hybrid vehicle 10 is also subjected to so-called eco-run (economy & ecology running) control in order to save fuel and reduce exhaust emissions. That is, for example, when the diesel hybrid vehicle 10 stops due to a signal waiting at an intersection or the like, the diesel engine 11 is automatically stopped under a predetermined stop condition, and then the predetermined restart condition (for example, the accelerator pedal is depressed). At a time), the diesel engine 11 is also restarted.

  The above is the basic configuration and basic control operation of the diesel hybrid vehicle 10 according to the present invention.

  Next, a control method during acceleration of the diesel hybrid vehicle 10 that is a main part of the present invention will be described with reference to FIGS. Here, FIG. 5 is a flowchart showing a control method of the diesel hybrid vehicle, and FIG. 6 is an explanatory diagram showing a sharing ratio of the torque assist amount according to the battery storage amount SOC. The following control is executed by the ECU.

  First, a deviation ΔTE (= TEP−TET) between the driver request torque TEP and the actual engine torque TET is calculated (step S10). The driver required torque TEP can be calculated based on a predetermined map or the like based on the accelerator opening and the engine speed. The actual engine torque TET can be calculated from the fuel injection amount and the engine speed.

  Next, it is determined whether the deviation ΔTE is positive or negative (step S11). If the deviation ΔTE is positive, that is, if the driver request torque TEP exceeds the actual engine torque TET (Yes in step S11), the engine torque corresponding to the deviation ΔTE is insufficient. It is necessary to assist by an electric supercharging system such as the assist turbo 26 or the motor generator 17.

  On the other hand, if the deviation ΔTE is not positive, that is, if the driver request torque TEP does not exceed the actual engine torque TET (No in step S11), the engine torque is not insufficient and torque assist is not necessary. After completing the control routine, the process returns to the normal basic control routine (not shown).

  When torque assist is performed by driving the electric supercharging system or the motor generator 17, the power of the battery 20 is consumed in a predetermined amount in any case, so that the current battery charge amount SOC is grasped and the battery charge amount SOC is determined. It is necessary to perform torque assist. Therefore, the current battery charge amount SOC is detected or estimated and the data is read (step S12), and it is determined whether or not the battery charge amount SOC exceeds a predetermined value k (step S13).

  As shown in FIG. 6, the predetermined value k is a threshold value of the battery storage amount SOC for determining whether to perform torque assist by the electric supercharging system or to perform torque assist by the motor generator 17. An optimal value (for example, 50%) is set in advance by experiments or the like. In FIG. 6, the maximum value of the battery storage amount SOC is about 80%, and the minimum value is about 45%.

  If the current battery charge amount SOC is smaller than the predetermined value k (Yes at step S13), the battery charge amount SOC has decreased, so torque assist for the deviation ΔTE is performed only by the electric supercharging system with low power consumption. carry out. That is, the sharing ratio of the torque assist amount by the electric supercharging system is 100%. By instructing the ECU to increase the turbo supercharging pressure by a predetermined amount, the fuel injection amount is increased to meet this. The engine torque is increased, and torque assist for the deviation ΔTE is performed (step S14). In this case, since the power consumption of the electric supercharging system is small, the amount of decrease in the battery storage amount SOC is also small. Therefore, it is possible to suppress an excessive decrease in the battery storage amount.

  Next, in order to perform feedback control of the torque assist amount in step S14, the deviation ΔTE is calculated again (step S15), and the sign of the deviation ΔTE is determined (step S16). If the deviation ΔTE is positive (Yes in step S16), the engine torque corresponding to the deviation ΔTE is still insufficient. To compensate for this, the torque assist amount is increased only by the electric supercharging system in the same manner as in step S14. (Step S17), the process returns to the normal basic control routine (not shown).

  On the other hand, when the deviation ΔTE is not positive (No in step S16), the shortage of the engine torque has been resolved, so that an electric supercharging system is used to suppress unnecessary increase in supercharging pressure and increase in fuel injection amount. Is reduced (step S18), and the process returns to the normal basic control routine (not shown).

  Thus, when the actual engine torque TET is insufficient with respect to the driver request torque TEP and the battery storage amount SOC is lower than the predetermined value k, torque assist is performed only by the electric supercharging system. Thus, it is possible to suppress a shortage of torque assist for the acceleration request while suppressing an excessive decrease in the battery storage amount SOC.

  On the other hand, if the current battery charge amount SOC is larger than the predetermined value k (No in step S13), the battery charge amount SOC is sufficient, so even if the motor generator 17 with high power consumption is driven, the battery charge amount is high. There is no risk of problems due to excessive reduction in SOC. Therefore, torque assist for the deviation ΔTE is performed only by the motor generator 17 (sharing ratio 100%) (step S19), and the process returns to the normal basic control routine (not shown). Thus, the torque assist request can be satisfied and the motor generator 17 is used, so that the torque assist can be efficiently performed without increasing the fuel consumption, and the fuel consumption can be improved.

  As described above, according to the diesel hybrid vehicle 10 and the control method thereof according to the first embodiment, when the actual engine torque TET is insufficient with respect to the driver request torque TEP, according to the battery storage amount SOC. By alternatively using the electric supercharging system or the motor generator 17 to assist torque, it is possible to suppress the battery storage amount SOC from excessively decreasing and the battery storage amount SOC has decreased to a predetermined value or less. Even in this case, it is possible to suppress a shortage of torque assist for the acceleration request.

  In the first embodiment, the present invention has been described as being applied to the front-wheel drive diesel hybrid vehicle 10, but is not limited thereto, and may be applied to a hybrid vehicle equipped with a gasoline engine. You may apply to a wheel drive vehicle and a four-wheel drive vehicle.

  Moreover, although demonstrated as what uses MMT12 as a stepped transmission, it is not limited to this, For example, an automatic transmission (AT) and a manual transmission (MT) may be sufficient.

  In the first embodiment, when the actual engine torque TET is insufficient with respect to the driver request torque TEP, the electric supercharging system or the motor generator 17 is selected according to the battery storage amount SOC. In this embodiment, torque assist is performed by using both the electric supercharging system and the motor generator 17 in addition to this.

  FIG. 7 is a flowchart showing a control method for a diesel hybrid vehicle according to Embodiment 2 of the present invention, and FIG. 8 is an explanatory diagram showing a sharing ratio of torque assist amounts according to the battery storage amount SOC. In the following description, members that are the same as or correspond to those already described are denoted by the same reference numerals, and redundant description is omitted or simplified.

  First, a deviation ΔTE (= TEP−TET) between the driver required torque TEP and the actual engine torque TET is calculated (step S20), and the sign of the deviation ΔTE is determined (step S21). If the deviation ΔTE is positive, that is, if the driver request torque TEP exceeds the actual engine torque TET (Yes in step S21), the engine torque corresponding to the deviation ΔTE is insufficient. It is necessary to assist by an electric supercharging system such as the assist turbo 26 or the motor generator 17.

  On the other hand, if the deviation ΔTE is not positive, that is, if the driver request torque TEP does not exceed the actual engine torque TET (No in step S21), the engine torque is not insufficient and torque assist is not necessary. After completing the control routine, the process returns to the normal basic control routine (not shown).

  Next, the current battery charge amount SOC is detected or estimated, and the data is read (step S22). The battery storage amount SOC has any magnitude relationship with respect to the first predetermined value SOC1 that is a predetermined threshold value of the battery storage amount SOC and the second predetermined value SOC2 that is larger than the first predetermined value SOC1. It is determined whether it has (see step S23 and step S29 in FIG. 7).

  For example, the first predetermined value SOC1 and the second predetermined value SOC2, and the share ratio of the torque assist amount between the electric supercharging system and the motor generator 17 can be defined as shown in FIG. That is, when the battery storage amount SOC is smaller than the first predetermined value SOC1, torque assist is performed only by the electric supercharging system, and when the battery storage amount SOC is larger than the second predetermined value SOC2, only the motor generator 17 is performed. When the battery charge amount SOC is between the first predetermined value SOC1 and the second predetermined value SOC2, torque assist is performed using the electric supercharging system and the motor generator 17 together. Can be defined as follows. These threshold values are set in advance by experiments or the like.

  Note that the share ratio of the torque assist amount in a region where the electric supercharging system and the motor generator 17 are used together (region of the first predetermined value SOC1 to the second predetermined value SOC2) continuously changes with a constant linear gradient. It is set to be. The maximum value of the battery storage amount SOC in FIG. 8 is about 80%, and the minimum value is about 45%.

  Now, if the current battery charge amount SOC is smaller than the first predetermined value SOC1 set as described above (Yes at step S23), the battery charge amount SOC is reduced, so that the power consumption is small. Torque assist for the deviation ΔTE is performed only by the electric supercharging system.

  That is, the turbocharge pressure of the electric supercharging system is instructed to increase by a predetermined amount, and the engine torque is increased by increasing the fuel injection amount to meet this, and torque assist for the deviation ΔTE is performed. (Step S24). In this case, since the power consumption of the electric supercharging system is small, the amount of decrease in the battery storage amount SOC is also small. Therefore, it is possible to suppress an excessive decrease in the battery storage amount.

  Next, in order to feedback control the torque assist amount in step S24, the deviation ΔTE is calculated again (step S25), and the sign of the deviation ΔTE is determined (step S26). When the deviation ΔTE is positive (Yes at Step S26), the engine torque corresponding to the deviation ΔTE is still insufficient, so that the torque assist amount by the electric supercharging system is increased in the same manner as Step S24 to compensate for this. (Step S27), the process returns to the normal basic control routine (not shown).

  On the other hand, if the deviation ΔTE is not positive (No at Step S26), the shortage of the engine torque has been resolved, so that the electric supercharging system is used to suppress unnecessary increase in supercharging pressure and increase in fuel injection amount. Is reduced (step S28), and the process returns to the normal basic control routine (not shown).

  As described above, when the actual engine torque TET is insufficient with respect to the driver request torque TEP and the battery storage amount SOC is lower than the first predetermined value SOC1, torque assist only by the electric supercharging system is performed. By implementing the above, it is possible to suppress a shortage of torque assist with respect to the acceleration request while suppressing an excessive decrease in the battery storage amount SOC.

  On the other hand, if the current battery charge amount SOC is larger than the first predetermined value SOC1 (No at Step S23), it is further determined whether or not it is larger than the second predetermined value SOC2 (Step S29). If the current battery charge amount SOC is larger than the second predetermined value SOC2 (Yes at step S29), the battery charge amount SOC has a margin, so even if the motor generator 17 with high power consumption is driven, the battery There is no risk of problems due to excessive reduction in the stored amount SOC.

  Therefore, torque assist for the deviation ΔTE is performed only by the motor generator 17 (step S30), and the process returns to the normal basic control routine (not shown). Thus, the torque assist request can be satisfied and the motor generator 17 is used, so that the torque assist can be efficiently performed without increasing the fuel consumption, and the fuel consumption can be improved.

  Further, when the current battery charge amount SOC is not larger than the second predetermined value SOC2 (No in step S29), that is, the current battery charge amount SOC is equal to the first predetermined value SOC1 and the second predetermined value SOC2. If it is between, the electric supercharging system and the motor generator 17 are used in combination to perform torque assist (step S31). As a result, it is possible to achieve appropriate torque assist while suppressing an excessive decrease in the battery charge amount.

  For example, as shown in FIG. 8, when the value of the battery storage amount SOC is s and is between the first predetermined value SOC <b> 1 and the second predetermined value SOC <b> 2, The sharing ratio becomes Ts%, and the sharing ratio of the torque assist amount by the electric supercharging system becomes (100−Ts)%.

  As described above, according to the control method of the diesel hybrid vehicle 10 according to the second embodiment, when the actual engine torque TET is insufficient with respect to the driver request torque TEP, the electric power is generated according to the battery storage amount SOC. By appropriately using one or both of the supercharging system or the motor generator 17 and performing torque assist, it is possible to suppress the battery storage amount SOC from being excessively reduced and to reduce the battery storage amount SOC to a predetermined value or less. Even in this case, it is possible to suppress a shortage of torque assist for the acceleration request.

  In the second embodiment, as shown in FIG. 8, in the region where the electric supercharging system and the motor generator 17 are used together, the sharing ratio of the torque assist amount is continuously changed with a constant linear gradient. However, the present invention is not limited to this. For example, it may be set so as to change in a curved line or in a stepwise manner.

  In the second embodiment, as shown in FIG. 8, in the region where the electric supercharging system and the motor generator 17 are used together (the region of the first predetermined value SOC1 to the second predetermined value SOC2), Although the sharing ratio has been described as being set so as to continuously change with a constant linear gradient, in the third embodiment, as shown in FIG. 9, the sharing ratio in the region is based on a predetermined supercharging efficiency map. It is configured so that the torque assist can be performed efficiently by setting. Here, FIG. 9 is an explanatory diagram showing a torque assist amount sharing ratio based on the supercharging efficiency map according to the third embodiment of the present invention.

  The above supercharging efficiency map is obtained by preliminarily obtaining a map of a condition that the supercharging efficiency by the electric supercharging system is good by an experiment or the like. Other configurations and control methods are the same as those in the case of the second embodiment, and a duplicate description is omitted.

  As described above, according to the control method of the diesel hybrid vehicle 10 according to the third embodiment, the same effect as in the second embodiment can be obtained, and the supercharging efficiency by the electric supercharging system can be improved. In addition, more appropriate torque assist can be realized.

  In the fourth embodiment, as shown in FIG. 10, the sharing ratio in the region where the electric supercharging system and the motor generator 17 are used together (the region of the first predetermined value SOC1 to the second predetermined value SOC2) is set to a predetermined overload. Set based on the feed efficiency map and set so that the share ratio of the torque assist amount becomes steeply zero in the combined use region and in the region where the torque assist amount is a minute amount below a predetermined value. It is a thing. Here, FIG. 10 is an explanatory diagram showing a share ratio of the torque assist amount according to the battery storage amount SOC according to the fourth embodiment of the present invention.

  That is, in the vicinity of the first predetermined value SOC1, which is one boundary of the combined region, there is a region T1 where the torque assist amount by the motor generator 17 is a minute amount equal to or less than the predetermined value. In such a small torque assist region T1, the efficiency of torque assist by the motor generator 17 is deteriorated. Therefore, the efficiency deterioration can be suppressed by setting the sharing ratio by the motor generator 17 to be steeply zero and switching to the torque assist by the electric supercharging system.

  Further, in the vicinity of the second predetermined value SOC2, which is one boundary of the combined region, there is a region T2 where the torque assist amount by the electric supercharging system is a minute amount equal to or less than the predetermined value. In such a small torque assist region T2, the efficiency of torque assist by the electric supercharging system is deteriorated. Therefore, by setting the sharing ratio by the electric supercharging system to be steeply zero and switching to torque assist by the motor generator 17, it is possible to suppress the deterioration of efficiency.

  This control method is suitable when the overall torque assist amount is large and the combined area is large compared to the case of the third embodiment. Other configurations and control methods are the same as those in the case of the third embodiment, and a duplicate description is omitted.

  As described above, according to the control method of the diesel hybrid vehicle 10 according to the fourth embodiment, the same effect as that of the third embodiment can be obtained, and also in a minute torque assist region where the torque assist efficiency is likely to deteriorate. , Efficiency deterioration can be suppressed.

  As described above, the hybrid vehicle and the control method thereof according to the present invention are useful for a parallel hybrid vehicle equipped with an electric supercharging system, and in particular, when the storage amount of a battery is reduced to a predetermined value or less. Also, it is suitable for a hybrid vehicle that can suppress a shortage of torque assist for an acceleration request.

1 is a schematic diagram showing a schematic configuration of a diesel hybrid vehicle according to Embodiment 1 of the present invention. It is a schematic diagram which shows the electric supercharging system by a motor assist turbocharger. It is a schematic diagram which shows the other electric supercharging system which combined the motor compressor with the turbocharger. It is a schematic diagram which shows another electric supercharging system. It is a flowchart which shows the control method of a diesel hybrid vehicle. It is explanatory drawing which shows the share ratio of the torque assist amount according to battery storage amount SOC. It is a flowchart which shows the control method of the diesel hybrid vehicle which concerns on Example 2 of this invention. It is explanatory drawing which shows the share ratio of the torque assist amount according to battery storage amount SOC. It is explanatory drawing which shows the share ratio of the torque assistance amount based on the supercharging efficiency map which concerns on Example 3 of this invention. It is explanatory drawing which shows the share ratio of the torque assist amount according to the battery electrical storage amount SOC which concerns on Example 4 of this invention.

Explanation of symbols

10 Diesel hybrid vehicle (hybrid vehicle)
11 Diesel engine (engine)
12 MMT (Stepped transmission)
17 Motor generator 20 Battery 23 Motor compressor (electric supercharging system)
26 Turbocharger (electric supercharging system)
k predetermined value SOC battery storage amount SOC1 first predetermined value SOC2 second predetermined value T1 minute torque assist region by motor generator T2 minute torque assist region by electric supercharging system

Claims (5)

An engine as a travel drive source, a stepped transmission, a motor generator for assisting the engine output by power generation or battery power by the engine output;
An electric supercharging system comprising a motor-assisted turbocharger or a turbocharger combined with a motor compressor;
An assist amount calculating means for calculating a torque assist amount based on a deviation between the driver request torque and the actual engine torque;
A storage amount detection means for detecting or estimating a storage amount of the battery;
The torque assist amount calculated by the assist amount calculating means is assisted using either or both of the motor generator and the electric supercharging system according to the battery charged amount detected or estimated by the charged amount detecting means. Torque assist control means for
Hybrid vehicle with An engine as a travel drive source, a stepped transmission, a motor generator for assisting the engine output by power generation or battery power by the engine output;
An electric supercharging system comprising a motor-assisted turbocharger or a turbocharger combined with a motor compressor;
An assist amount calculating means for calculating a torque assist amount based on a deviation between the driver request torque and the actual engine torque;
A storage amount detection means for detecting or estimating a storage amount of the battery;
The torque assist amount calculated by the assist amount calculating means is assisted using either or both of the motor generator and the electric supercharging system according to the battery charged amount detected or estimated by the charged amount detecting means. Torque assist control means for
A hybrid vehicle control method comprising:
When the battery storage amount is small, while torque assist by the electric supercharging system,
A control method for a hybrid vehicle, characterized in that when the battery storage amount is large, torque is assisted by the motor generator. An engine as a travel drive source, a stepped transmission, a motor generator for assisting the engine output by power generation or battery power by the engine output;
An electric supercharging system comprising a motor-assisted turbocharger or a turbocharger combined with a motor compressor;
An assist amount calculating means for calculating a torque assist amount based on a deviation between the driver request torque and the actual engine torque;
A storage amount detection means for detecting or estimating a storage amount of the battery;
The torque assist amount calculated by the assist amount calculating means is assisted using either or both of the motor generator and the electric supercharging system according to the battery charged amount detected or estimated by the charged amount detecting means. Torque assist control means for
A hybrid vehicle control method comprising:
When the battery storage amount is less than the first predetermined value, while the torque is assisted by the electric supercharging system,
When the battery storage amount is equal to or greater than a second predetermined value that is greater than the first predetermined value, torque assist is performed by the motor generator,
A hybrid vehicle characterized in that when the battery storage amount is between the first predetermined value and the second predetermined value, the electric supercharging system and the motor generator are used together for torque assist. Control method.   4. The hybrid according to claim 3, wherein in a region where torque assist is performed by using the electric supercharging system and the motor generator in combination, a share ratio between the torque assist amounts of both is changed based on a supercharging efficiency map. 5. Vehicle control method.   In a region where torque assist is performed using the electric supercharging system and the motor generator in combination, and the torque assist amount is a minute amount equal to or less than a predetermined value, the share ratio of the torque assist amount is steep. The hybrid vehicle control method according to claim 4, wherein the hybrid vehicle control method is set to be zero.

Images