JP2015168300A - Hybrid car - Google Patents

Abstract

A system efficiency of a vehicle is largely prevented from being lowered during reverse travel.
When a 2WD instruction switch is on, a shift position SP is in an R position (S210), and a traveling torque Td * cannot be satisfied in a 2WD mode (S220), and an output from an engine 22 in the 2WD mode is output. When the target power Pe1 to be set is larger than the optimum fuel consumption power Pe2 in which the system is optimal in the 4WD mode (system loss is minimized) (S250, S260), the 4WD mode is set to the travel mode (S270). Then, the engine is operated at an operation point corresponding to the optimum fuel efficiency power Pe2.
[Selection] Figure 3

Description

  The present invention relates to a hybrid vehicle, and more specifically, an engine that outputs a driving force for forward travel to a first axle, a motor that outputs a driving force to a second axle, a battery that exchanges power with the motor, a first An instruction switch that allows the driver to instruct traveling in the first mode among the first mode that outputs driving force only to the axle and the second mode that outputs driving force to the first axle and the second axle; It relates to a hybrid vehicle equipped.

  Conventionally, this type of hybrid vehicle includes an engine that drives a front wheel drive shaft, a starter motor that starts and rotates the engine, and a torque converter and automatic transmission with a lock-up clutch that is interposed between the engine and the front wheel drive shaft. And an electric motor that drives the rear wheel drive shaft, and is configured to be able to select a 2WD mode in which the vehicle travels only by the driving force of the engine and a 4WD mode in which the vehicle travels by the driving force of the engine and motor Has been proposed (see, for example, Patent Document 1). In this hybrid vehicle, when the engine restart condition (idle stop release condition) is satisfied, the starter motor is driven to restart the engine. However, immediately after this restart, the lockup clutch is released, and the vehicle travels by the driving force of the motor regardless of whether the 2WD mode or the 4WD mode is selected. After that, after the engine rotation is stabilized, the lockup clutch is engaged so that the driving force of the engine is transmitted to the front wheel drive shaft.

JP 2005-54858 A

  In a hybrid vehicle that outputs a driving force for forward travel from the engine to the front wheel drive shaft and outputs a driving force from the motor to the rear wheel drive shaft, if the power is output from the engine during reverse travel, the reverse travel torque (power ) Is preferably reduced, the engine is preferably stopped or operated independently. However, when charging of the battery using the power from the engine is required, the engine needs to be loaded. When the 2WD mode is selected by the driver and the vehicle travels backward, if the vehicle travels backward in the 2WD mode according to the selection, the system efficiency of the vehicle may be greatly reduced depending on the engine power.

  The main purpose of the hybrid vehicle of the present invention is to suppress a significant reduction in the system efficiency of the vehicle during reverse travel.

  The hybrid vehicle of the present invention employs the following means in order to achieve the main object described above.

The hybrid vehicle of the present invention
An engine that outputs driving force for forward travel to the first axle, a motor that outputs driving force to the second axle, a battery that exchanges power with the motor, and a driving force that outputs driving force only to the first axle. A hybrid vehicle comprising: an instruction switch that allows a driver to instruct traveling in the first mode among a first mode and a second mode that outputs driving force to the first axle and the second axle. ,
The control means is configured such that when the first mode is instructed by the instruction switch, the target power to be output from the engine in the first mode is based on the system loss in the second mode during reverse travel. Control means for controlling the engine and the motor so as to run in the second mode when the obtained fuel efficiency optimum power is greater;
It is characterized by providing.

  In the hybrid vehicle of the present invention, when the first mode is instructed by the instruction switch, the target power to be output from the engine in the first mode is obtained based on the system loss in the second mode during reverse travel. When the fuel efficiency is greater than the optimum power (the engine power at which the system loss is minimized), the engine and the motor are controlled to run in the second mode. Thereby, compared with what drive | works in 1st mode according to a driver | operator's instruction | indication, it can suppress that power more than necessary is output from an engine, and can improve the system efficiency of a vehicle. That is, it is possible to prevent the system efficiency of the vehicle from greatly decreasing during reverse travel.

1 is a configuration diagram showing an outline of a configuration of a hybrid vehicle 20 as an embodiment of the present invention. It is a flowchart which shows an example of the driving mode setting routine performed by the electronic control unit of an Example. It is a flowchart which shows an example of a process at the time of 2WD instruction | indication ON. It is explanatory drawing which shows an example of the driving points A and B based on each of target power Pe1 and fuel consumption optimal power Pe2 when the target power Pe1 of 2WD mode is larger than the fuel consumption optimal power Pe2 of 4WD mode at the time of reverse drive. It is explanatory drawing which shows an example of the relationship between the vehicle speed V and system loss PL (2WD), PL (4WD) when the target power Pe1 of 2WD mode is larger than the fuel consumption optimal power Pe2 of 4WD mode at the time of reverse drive.

  Next, the form for implementing this invention is demonstrated using an Example.

  FIG. 1 is a configuration diagram showing an outline of the configuration of a hybrid vehicle 20 as an embodiment of the present invention. As shown in the figure, the hybrid vehicle 20 of the embodiment has a carrier connected to an engine 22 that outputs power using gasoline, light oil or the like as a fuel, and a crankshaft as an output shaft of the engine 22, and the front wheels 38 a and 38 b have differentials. A planetary gear 30 in which a ring gear is connected to a drive shaft 36F connected via a gear 37F, a motor MG1 that is configured as a synchronous generator motor and a rotor is connected to a sun gear of the planetary gear 30, and a synchronous generator motor, for example. The motor MG2 in which the rotor is connected to the drive shaft 36F, and the motor in which the rotor is connected to the drive shaft 36R configured as a synchronous generator motor and connected to the rear wheels 38c and 38d via the differential gear 37R, for example. MG3 and motors MG1, MG2, MG3 Inverters 41, 42, 43 for operating, a battery 50 configured as, for example, a lithium ion secondary battery and exchanging electric power with motors MG1, MG2, MG3 via inverters 41, 42, 43, and the entire vehicle are controlled Electronic control unit 70.

  Although not shown, the electronic control unit 70 is configured as a microprocessor centered on a CPU, and includes a ROM for storing a processing program, a RAM for temporarily storing data, and an input / output port in addition to the CPU. The electronic control unit 70 manages signals from various sensors necessary for controlling the operation of the engine 22, signals from various sensors necessary for driving and controlling the motors MG1, MG2, and MG3, and the battery 50. Necessary signals from various sensors, an ignition signal from the ignition switch 80, a shift position SP from the shift position sensor 82 for detecting the operation position of the shift lever 81, and an accelerator opening sensor 84 for detecting the depression amount of the accelerator pedal 83 The accelerator pedal opening Acc, the brake pedal position BP from the brake pedal position sensor 86 for detecting the depression amount of the brake pedal 85, the vehicle speed V from the vehicle speed sensor 88, the front wheels 38a among the front wheels 38a, 38b and the rear wheels 38c, 38d. , 38b is output only to the driving force A four-wheel drive (4WD) mode for outputting a driving force to the front wheels 38a and 38b and the rear wheels 38c and 38d, a switch signal from the 2WD instruction switch 89 for the driver to instruct traveling in the wheel drive (2WD) mode. A switch signal or the like from the 4WD instruction switch 90 for the driver to instruct traveling is input via the input port. Note that both the 2WD instruction switch 89 and the 4WD instruction switch 90 are configured not to be turned on. From the electronic control unit 70, various control signals for controlling the operation of the engine 22, switching control signals to switching elements (not shown) of the inverters 41, 42, 43, and the like are output via an output port. The electronic control unit 70 calculates the rotational speed Ne of the engine 22 based on a signal from a crank position sensor (not shown) attached to the crankshaft of the engine 22, and rotates the rotors of the motors MG1, MG2, and MG3. Based on the rotational positions θm1, θm2, and θm3 of the rotors of the motors MG1, MG2, and MG3 from the rotational position detection sensor that detects the position, the rotational speeds Nm1, Nm2, and Nm3 of the motors MG1, MG2, and MG3 are calculated, and the battery Based on the integrated value of the charge / discharge current Ib of the battery 50 from the current sensor attached to the output terminal 50, the storage ratio SOC, which is the ratio of the capacity of the electric power that can be discharged from the battery 50 at that time to the total capacity, is calculated. Or

  In the hybrid vehicle 20 of the embodiment, the operation position of the shift lever 81 (shift position SP detected by the shift position sensor 82) includes a parking position (P position) used during parking, and a reverse position (R for reverse travel). Position), neutral position (N position), forward drive position (D position), etc.

  The hybrid vehicle 20 of the embodiment configured in this way is in 2WD mode or 4WD mode, hybrid traveling (HV traveling) that travels with the operation of the engine 22 or electric traveling (EV traveling) that stops the operation of the engine 22 and travels. ).

  In the HV traveling in the 2WD mode, the electronic control unit 70 sets the traveling torque Td * required for traveling based on the accelerator opening Acc from the accelerator opening sensor 84 and the vehicle speed V from the vehicle speed sensor 88, The engine 22 and the motors MG1, MG2 (inverter 41) are driven so that the traveling torque Td * is output to the front wheels 38a, 38b while the engine 22 is operated at the operating point on the fuel efficiency operation line for efficiently operating the engine 22. , 42).

  In the 2WD mode EV running, the electronic control unit 70 sets the running torque Td * in the same manner as described above, and the running torque Td * is output from the motor MG2 to the front wheels 38a, 38b so as to run the motor MG2. (Inverter 42) is controlled.

  In the HV traveling in the 4WD mode, the traveling torque Td * is set in the same manner as described above, and the traveling torque Td * is multiplied by the front wheel side torque distribution ratio Dtf to set the front wheel traveling torque Tf * and for traveling. The rear wheel side torque distribution ratio Dtr (= 1−Dtf) is multiplied by the torque Td * to set the rear wheel side running torque Tr *, and the front wheels 38a, 38b are operated while the engine 22 is operated at the driving point on the fuel consumption operation line. The front wheel side travel torque Tf * is output to the rear wheel 38c, 38d from the motor MG3 and the rear wheel side travel torque Tr * is output from the motor MG3 to the engine 22 and the motors MG1, MG2, MG3 (inverters 41, 42, 43).

  In the HV traveling in the 4WD mode, the traveling torque Td *, the front wheel traveling torque Tf *, and the rear wheel traveling torque Tr * are set in the same manner as described above, and the front wheels 38a and 38b are driven from the motor MG2. The motor MG2 and MG3 (inverters 42 and 43) are controlled so that the vehicle travels with the output torque Tf * and the rear wheel side traveling torque Tr * output from the motor MG3 to the rear wheels 38c and 38d.

  Next, the operation of the hybrid vehicle 20 of the embodiment configured as described above, particularly the operation when setting the traveling mode (2WD mode or 4WD mode) will be described. FIG. 2 is a flowchart illustrating an example of a travel mode setting routine executed by the electronic control unit of the embodiment. This routine is repeatedly executed every predetermined time.

  When the travel mode setting routine is executed, the electronic control unit 70 first inputs data such as a switch signal from the 2WD instruction switch 89 or the 4WD instruction switch 90 (step S100), and whether or not the 2WD instruction switch 89 is on. And whether or not the 4WD instruction switch 90 is ON (steps S110 and S120).

  When both the 2WD instruction switch 89 and the 4WD instruction switch 90 are off, the 2WD mode or the 4WD mode is set to the traveling mode according to the traveling condition or the like (step S130), and this routine is terminated. In the embodiment, the 2WD mode or the 4WD mode is selected in consideration of power performance and vehicle running stability. For example, when starting, when the running torque Td * cannot be satisfied only by the front wheels 38a, 38b, or when slip occurs in the front wheels 38a, 38b, the 4WD mode is set to the running mode, Sometimes, the 2WD mode can be set to the travel mode. Further, when traveling in the 4WD mode, the front wheel side torque distribution rate Dtf and the rear wheel side torque distribution rate Dtr are set in accordance with the traveling conditions (whether starting, slipping, road gradient, etc.). It was supposed to be set.

  When the 2WD instruction switch 89 is off and the 4WD instruction switch 90 is on, the 4WD mode is set to the travel mode (step S140), and the front wheel side torque distribution ratio Dtf and the rear wheel side torque distribution ratio Dtr are set (step S150). ), This routine is terminated.

  When the 2WD instruction switch 89 is on, the travel mode is set by the 2WD instruction on process illustrated in FIG. 3 (step S160), and this routine ends.

  Next, the 2WD instruction on process of FIG. 3 will be described. In the 2WD instruction on process, the electronic control unit 70 first inputs data such as the shift position SP from the shift position sensor 82, the storage ratio SOC of the battery 50, and the running torque Td * (step S200). Here, as the storage ratio SOC of the battery 50, a value calculated based on an integrated value of the charge / discharge current Ib of the battery 50 from a current sensor (not shown) is input. Further, as the traveling torque Td *, a value set by the accelerator opening Acc and the vehicle speed V is input.

  When the data is thus input, it is determined whether or not the input shift position SP is the R position, whether or not the engine 22 is in operation, and whether or not the storage ratio SOC of the battery 50 is equal to or less than the threshold value Sref (steps S210 to S230). Here, the threshold value Sref is determined as the upper limit of the power storage ratio range in which the battery 50 needs to be forcibly charged, and for example, a value such as 35% or 40% can be used. In the hybrid vehicle 20, the torque output from the engine 22 to the drive shaft 36F via the planetary gear 30 is torque for forward travel. Therefore, when the shift position SP is in the R position (reverse travel), the engine 22 The motor (MG) or the motor MG3 suppresses the output of the torque (power) by stopping the operation of the vehicle or performing independent operation, and the vehicle travels while satisfying the traveling torque Td * (power) by the torque (power) from the motor MG2 or MG3. Is preferred. However, when the storage ratio SOC of the battery 50 is low, in order to suppress an excessive decrease in the storage ratio SOC, the reverse charging process is performed in which the engine 22 is loaded and power is generated by the motor MG1 using the power. There is a need. The determination process of steps S210 to S230 is a process of determining whether or not the reverse charging process is necessary.

  When the shift position is not the R position (D position or the like), or when the engine 22 is not operated, and when the storage ratio SOC of the battery 50 is greater than the threshold value Sref, the reverse charging process is not required (engine 22). The 2WD mode is set to the traveling mode according to the driver's instruction (2WD instruction switch 89 is turned on) (step S290), and this routine is finished.

  When the shift position is the R position and the engine 22 is in operation and the storage ratio SOC of the battery 50 is less than or equal to the threshold value Sref, the reverse charging process is required (the engine 22 needs to be loaded). It is determined whether or not the traveling torque Td * is large, specifically, whether or not the traveling torque Td * can be satisfied only by the torque from the motor MG2 while executing the reverse charging process. (Step S240). This determination is a process for determining whether or not the traveling torque Td * can be satisfied in the 2WD mode.

  When the traveling torque Td * can be satisfied only by the torque from the motor MG2 while performing the reverse charging process, it is determined that the traveling torque Td * can be satisfied in the 2WD mode, and the driver's instruction (2WD The 2WD mode is set to the traveling mode in accordance with the instruction switch 89 being turned on (step S290), and this routine is terminated.

  When the traveling torque Td * cannot be satisfied only by the torque from the motor MG2 while performing the reverse charging process, the traveling torque Td * cannot be satisfied in the 2WD mode, that is, the traveling torque Td * is satisfied. Therefore, it is determined that it is necessary to travel in the 4WD mode, and the target power Pe1 to be output from the engine 22 in the 2WD mode and the power of the engine 22 that optimizes the system in the 4WD mode (the system loss is minimized) Pe2) (referred to as optimum fuel efficiency power) is compared (steps S250 and S260).

  The calculation of the target power Pe1 in the 2WD mode is based on the traveling power Pd * obtained according to the traveling torque Td * and the vehicle speed V, and the charge / discharge required power Pb * of the battery 50 based on the storage ratio SOC of the battery 50 (battery This is done by subtracting the positive value when discharging from 50 and adding the system loss PL (2WD) to this. In this case, the system loss PL (2WD) is the sum of the loss (including inertia) PLe of the engine 22, the losses PLm1 and PLm2 of the motors MG1 and MG2, and the loss PLh of the auxiliary equipment (such as an air conditioner and a DC / DC converter). As calculated.

  In addition, the optimum fuel efficiency power Pe2 in the 4WD mode is set by gradually changing the front wheel side power distribution ratio Dpf among the front wheel side power distribution ratio Dpf and the rear wheel side power distribution ratio Dpr (= 1-Dpf). The system loss PL (4WD) at the front wheel side power distribution ratio Dpf is calculated, the front wheel side power distribution ratio Dpf that minimizes the system loss PL (4WD) is obtained, and the engine 22 corresponding to the front wheel side power distribution ratio Dpf is calculated. The power is set to the optimum fuel consumption power Pe2. The system loss PL (4WD) in this case is the sum of the loss PLe of the engine 22, the losses PLm1, PLm2, and PLm3 of the motors MG1, MG2, and MG3 and the loss PLh of the auxiliary equipment (such as an air conditioner and a DC / DC converter). Calculated. Compared with system loss PL (2WD), this system loss PL (4WD) increases the loss PLm3 (rear wheel side loss) of the motor MG3 and decreases the loss PLe of the engine 22 as the front wheel side power distribution ratio Dpf is smaller. Loss PLm1, PLm2 (front wheel side loss) of motors MG1, MG2 decreases. Therefore, by gradually changing the front wheel side power distribution rate Dpf, the front wheel side power distribution rate Dpf that minimizes the system loss PL (4WD) can be obtained.

  When the target power Pe1 in the 2WD mode is equal to or less than the optimum fuel consumption power Pe2 in the 4WD mode, the 2WD mode is set to the traveling mode according to the driver's instruction (the 2WD instruction switch 89 is turned on) (step S290), and this routine is terminated. .

  On the other hand, when the target power Pe1 in the 2WD mode is larger than the optimum fuel consumption power Pe2 in the 4WD mode, the torque (power) from the engine 22 does not contribute to the reverse travel (reducing the torque for the reverse travel) when traveling in the 2WD mode. Nevertheless, it is determined that the system efficiency is not good because it is necessary to output a larger power than the 4WD mode, and the 4WD mode is set to the traveling mode (step S270), and the front wheel side according to the above-described front wheel side power distribution ratio Dpf. The torque distribution rate Dtf and the rear wheel side torque distribution rate Dtr are set (step S280), and this routine ends. In this case, the engine 22 is operated at an operation point corresponding to the fuel efficiency optimum power Pe2 and the fuel efficiency operation line. By driving in the 4WD mode in this manner, the driver's instruction (2WD instruction switch 89 is turned on) is rejected. However, the engine 22 has more power than necessary as compared with the case where the driver's instruction is followed. Can be suppressed and system efficiency can be improved.

  FIG. 4 is an explanatory diagram showing an example of driving points A and B based on the target power Pe1 and the optimum fuel consumption power Pe2 when the target power Pe1 in the 2WD mode is larger than the optimum fuel consumption power Pe2 in the 4WD mode during reverse travel. FIG. 4 also shows fuel efficiency operation lines and system efficiency contours. In the case of FIG. 4, it can be seen that when traveling in the 2WD mode, a larger amount of power is output from the engine 22 and the system efficiency is lower than when traveling in the 4WD mode. Therefore, in the embodiment, in such a case, the vehicle travels in the 4WD mode (the engine 22 is driven at an operation point corresponding to the fuel efficiency optimum power Pe2). Thereby, system efficiency can be improved.

  FIG. 5 is an explanatory diagram showing an example of the relationship between the vehicle speed V and the system losses PL (2WD) and PL (4WD) when the target power Pe1 in the 2WD mode is greater than the fuel efficiency optimum power Pe2 in the 4WD mode during reverse travel. In FIG. 5, in the case of the torque Td1 with the traveling torque Td *, the torque Td1 is output on the front wheel side in the 2WD mode, the torque Td1 · Dtf (for example, Td1 · 2/3) and the rear side on the front wheel side in the 4WD mode. A case where torque Td1 · Dtr (for example, Td1 · 1/3) is output on the wheel side is shown. From FIG. 5, it can be seen that in the 4WD mode, the rear wheel side loss increases and the front wheel side loss decreases as compared to the 2WD mode. Therefore, if the front wheel side power distribution ratio Dpf and thus the optimum fuel consumption power Pe2 are set so that the system loss PL (4WD) is minimized, the 4WD mode is set to the traveling mode when the efficiency is improved in the 4WD mode over the 2WD mode. By doing so, the system efficiency can be improved.

  According to the hybrid vehicle 20 of the embodiment described above, when the 2WD instruction switch 89 is on, the shift position SP is the R position, and the traveling torque Td * cannot be satisfied in the 2WD mode, and the 2WD mode switch When the target power Pe1 to be output from the engine 22 is larger than the optimum fuel consumption power Pe2 in the 4WD mode (system loss is minimized), the vehicle travels in the 4WD mode (engine at a driving point corresponding to the optimum fuel consumption power Pe2). Therefore, the system efficiency can be improved as compared with the case of following the driver's instructions. It is possible to prevent the system efficiency of the vehicle from greatly decreasing during reverse travel.

  In the hybrid vehicle 20 of the embodiment, when the 2WD instruction switch 89 is on and the shift position SP is the R position, the driving torque Td * cannot be satisfied in the 2WD mode and the target power Pe1 in the 2WD mode is in the 4WD mode. When the fuel efficiency optimum power Pe2 is greater, the vehicle travels in the 4WD mode, and when the travel torque Td * can be satisfied in the 2WD mode, or when the target power Pe1 in the 2WD mode is less than the fuel consumption optimum power Pe2 in the 4WD mode, the 2WD mode In the 2WD mode, the target power of the 2WD mode is set regardless of whether or not the running torque Td * can be satisfied (without executing step S240 of the 2WD instruction on process in FIG. 3). Pe1 is greater than 4WD mode fuel efficiency optimal power Pe2 Traveling at Kiniwa 4WD mode, or as being run in 2WD mode when the target power Pe1 the 2WD mode is optimum fuel economy power Pe2 following 4WD mode.

  In the embodiment, the hybrid vehicle 20 includes the front wheel side engine 22, the motor MG1, the motor MG2, and the rear wheel side motor MG3. However, the engine 22 is operated at an arbitrary operating point on the front wheel side. For example, the motor may be attached to the drive shaft 36F connected to the front wheels 38a and 38b via a continuously variable transmission, and the engine may be connected to the rotation shaft of the motor via a clutch. The engine may be connected to the drive shaft 36F via a continuously variable transmission.

  The correspondence between the main elements of the embodiment and the main elements of the invention described in the column of means for solving the problems will be described. In the embodiment, the engine 22 corresponds to the “engine”, the motor MG3 corresponds to the “motor”, the battery 50 corresponds to the “battery”, the 2WD instruction switch 89 corresponds to the “instruction switch”, and the electronic control unit 70 corresponds to “control means”.

  The correspondence between the main elements of the embodiment and the main elements of the invention described in the column of means for solving the problem is the same as that of the embodiment described in the column of means for solving the problem. Therefore, the elements of the invention described in the column of means for solving the problems are not limited. That is, the interpretation of the invention described in the column of means for solving the problems should be made based on the description of the column, and the examples are those of the invention described in the column of means for solving the problems. It is only a specific example.

  As mentioned above, although the form for implementing this invention was demonstrated using the Example, this invention is not limited at all to such an Example, In the range which does not deviate from the summary of this invention, it is with various forms. Of course, it can be implemented.

  The present invention can be used in the manufacturing industry of hybrid vehicles.

  20 hybrid vehicle, 22 engine, 30 planetary gear, 36F, 36R drive shaft, 38a, 38b front wheel, 38c, 38d rear wheel, 41, 42, 43 inverter, 50 battery, 70 electronic control unit, 80 ignition switch, 81 shift lever, 82 shift position sensor, 83 accelerator pedal, 84 accelerator opening sensor, 85 brake pedal, 86 brake pedal position sensor, 88 vehicle speed sensor 89 2WD indicating switch, 904WD indicating switch, MG1, MG2, MG3 motor.

Claims (1)

An engine that outputs driving force for forward travel to the first axle, a motor that outputs driving force to the second axle, a battery that exchanges power with the motor, and a driving force that outputs driving force only to the first axle. A hybrid vehicle comprising: an instruction switch that allows a driver to instruct traveling in the first mode among a first mode and a second mode that outputs driving force to the first axle and the second axle. ,
The control means is configured such that when the first mode is instructed by the instruction switch, the target power to be output from the engine in the first mode is based on the system loss in the second mode during reverse travel. Control means for controlling the engine and the motor so as to run in the second mode when the obtained fuel efficiency optimum power is greater;
A hybrid vehicle comprising:

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