JP2010254101A - Hybrid car - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To more appropriately suppress the overcharge of a battery even when the power of an engine rapidly increases such as in sudden acceleration. <P>SOLUTION: An average estimation power Peave as the average value of engine estimation powers Peest calculated in the latest past three time execution of an engine operation time drive control routine is calculated, and the average estimation power Peave calculated in the previous execution of the routine is subtracted from the calculated average estimation power Peave to calculate estimation power variation ΔPeave. Then, when the estimation power variation ΔPeave is less than a prescribed reference value ΔPeref, a reflection rate α as the rate of the reflection of an inertia Ti on an estimation power Peest in calculating the estimation power Peest is set to a first value α1, and when the estimation power variation ΔPeest is equal to or more than the reference value ΔPeref, the reflection rate α is set to a second value α2 which is larger than the first value α1. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a hybrid vehicle.

  Conventionally, in this type of hybrid vehicle, the estimated power estimated to be output from the engine is calculated in consideration of the inertia of the system composed of the engine and the motor MG1, and the calculated estimated power and the drive shaft are output. By setting the upper limit power, which is the power allowed for the engine output based on the current power and the input limit of the battery, and setting the target power of the engine within the set upper limit power range, it is more than necessary from the engine In order to prevent the battery from being over-charged, it has been proposed to suppress overcharging of the battery (see, for example, Patent Document 1). In this hybrid vehicle, when the friction is large and the engine rotation is unstable, such as immediately after the engine is started or when the engine temperature is low, the inertia power with respect to the estimated power is suppressed in order to suppress the deterioration of the estimated power calculation accuracy due to the fluctuation of the inertia. The reflection rate is set small.

JP 2006-315664 A

  However, in the above-described hybrid vehicle, after a certain amount of time has elapsed since the engine was started or when the engine temperature is equal to or higher than a predetermined temperature, the magnitude of the influence of inertia is not taken into consideration, so that the vehicle is suddenly accelerated. If the estimated power of the engine is not accurately calculated and the upper limit power of the engine is set high, there is a possibility that the engine will output more power than necessary and the battery will be overcharged.

  The main purpose of the hybrid vehicle of the present invention is to more appropriately suppress overcharging of the power storage device even when the power of the internal combustion engine increases rapidly, such as during rapid acceleration.

  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 is connected to three shafts of an internal combustion engine, a first motor capable of inputting / outputting power, an output shaft of the internal combustion engine, a rotation shaft of the first motor, and a drive shaft. Power distribution means for inputting / outputting power based on power input / output to / from any two shafts to / from the remaining shaft, a second motor capable of inputting / outputting power to / from the drive shaft, and the first and second motors Power storage means capable of exchanging electric power, allowable charge power setting means for setting allowable charge power that is power allowed for charging of the power storage means, and required power for setting required power required for the internal combustion engine An inertia of the system consisting of the internal combustion engine and the first electric motor is calculated based on the product of the setting means and the moment of inertia of the system consisting of the internal combustion engine and the first electric motor and the time derivative of the rotational speed of the internal combustion engine. Inner An estimation unit that calculates an estimated power that is estimated to be output from the internal combustion engine based on the torque output from the first electric motor, the rotational speed of the internal combustion engine, and the calculated inertia Power that is allowed for output of the internal combustion engine based on power calculation means, drive shaft power output to the drive shaft, allowable charging power of the set power storage means, and the calculated estimated power Upper limit power setting means for setting an upper limit power, target power setting means for setting the target power to be output from the internal combustion engine by limiting the set required power with the set upper limit power, and the set The internal combustion engine is configured such that a target power is output from the internal combustion engine and a torque based on a required torque required for traveling is output to the drive shaft. A hybrid vehicle and a control means for controlling said first and second motors,
When the fluctuation amount of the estimated power is less than a predetermined reference value, when calculating the estimated power, a reflection rate that is a ratio of reflecting the calculated inertia in the estimated power is set to a first value. The gist of the invention is that it includes a reflection rate setting means for setting the reflection rate to a second value larger than the first value when the estimated power fluctuation amount is equal to or greater than the reference value.

  In the hybrid vehicle of the present invention, when the fluctuation amount of the estimated power of the internal combustion engine is less than the predetermined reference value, the inertia reflection rate is set to the first value, and the fluctuation amount of the estimated power is equal to or greater than the predetermined reference value. If it is, the reflection rate is set to a second value larger than the first value. As described above, when the fluctuation amount of the estimated power of the internal combustion engine is small and the influence of inertia is small, the estimated power of the internal combustion engine is not reflected excessively by setting the first value as a reflection rate relatively small. Can be calculated accurately, and the internal combustion engine can be more appropriately controlled based on the calculated estimated power. Further, when the fluctuation amount of the estimated power of the internal combustion engine is large and the influence of inertia is large, the reflection rate is set to a second value larger than the first value, so that the inertia is reflected more appropriately. The estimated power can be calculated with higher accuracy, and the upper limit power of the internal combustion engine can be set more appropriately. Then, by operating the internal combustion engine within the set upper limit power range, even if the power of the internal combustion engine suddenly increases, such as during sudden acceleration, the power storage device prevents the internal combustion engine from outputting more power than necessary. Overcharge can be suppressed more appropriately.

1 is a schematic configuration diagram of a hybrid vehicle 20 according to an embodiment of the present invention. It is explanatory drawing which shows an example of the map for inertia reflection ratio setting.

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

  FIG. 1 is a schematic configuration diagram of a hybrid vehicle according to an embodiment of the present invention. As shown in the figure, the hybrid vehicle 20 of the embodiment includes an engine 22 that uses gasoline, light oil, or the like as fuel, an engine electronic control unit (hereinafter referred to as “engine ECU”) 24 that drives and controls the engine 22, and an engine 22. A planetary gear 30 in which a carrier 34 is connected to a crankshaft 26 as an output shaft via a damper 28, a motor MG 1 capable of generating power connected to a sun gear 31 of the planetary gear 30, and a drive connected to a ring gear 32 of the planetary gear 30. A reduction gear 35 connected to a ring gear shaft 32a as a shaft, a motor MG2 connected to the ring gear shaft 32a via the reduction gear 35, and a gear mechanism 37 and a differential gear 38 connected to the ring gear shaft 32a. Drive wheels 39a, 39b, motor MG1, and Inverter 41 interposed between power line 54, inverter 42 interposed between motor MG2 and power line 54, and a motor for driving and controlling motors MG1 and MG2 via inverters 41 and 42 An electronic control unit (hereinafter referred to as “motor ECU”) 40, a battery 50, for example, a lithium ion secondary battery or a nickel hydride secondary battery connected to the power line 54, and a battery control unit that manages the battery 50 ( (Hereinafter referred to as “battery ECU”) 52 and a hybrid electronic control unit (hereinafter referred to as “hybrid ECU”) 70 that controls the entire vehicle while communicating with engine ECU 24, motor ECU 40, and battery ECU 52.

  The motor ECU 40 calculates data related to the motors MG1 and MG2, such as the rotational speeds Nm1 and Nm2 of the motors MG1 and MG2 based on signals from rotational position detection sensors 43 and 44 that detect the rotational positions of the rotors of the motors MG1 and MG2. In order to manage the battery 50, the battery ECU 52 calculates the remaining capacity SOC of the battery 50, calculates the charge / discharge required power Pb * of the battery 50 based on the remaining capacity SOC and predetermined charge / discharge constraints, Based on the remaining capacity SOC of the battery 50 and the temperature of the battery 50, the input limit Win as the allowable charge power that is the power allowed for charging the battery 50 and the allowable discharge power that is the power allowed for discharging the battery 50 Or the output limit Wout.

  Next, an operation when the engine 22 is operated in the hybrid vehicle 20 configured as described above will be described. In the hybrid vehicle 20 of the embodiment, when the engine 22 is being operated, an engine operation drive control routine (not shown) is executed by the hybrid ECU 70 every predetermined time (for example, every several milliseconds). When the engine operation drive control routine is executed, the hybrid ECU 70 determines the accelerator opening Acc from the accelerator pedal position sensor 84, the vehicle speed V from the vehicle speed sensor 87, the rotation speed Ne of the engine 22, and the rotations of the motors MG1 and MG2. Input processing of data necessary for control such as the numbers Nm1 and Nm2, the input / output limits Win and Wout of the battery 50, and the charge / discharge request power Pb * is executed. Here, the rotational speed Ne of the engine 22 is calculated by the engine ECU 24 based on a crank position from a crank position sensor (not shown), and is input from the engine ECU 24 by communication. Further, the rotational speeds Nm1, Nm2 of the motors MG1, MG2 are input from the motor ECU 40 through communication, and the input / output limits Win, Wout and the charge / discharge request power Pb * of the battery 50 are input from the battery ECU 52 through communication. It is what is done.

  After such an input process, the hybrid ECU 70 calculates the required torque Tr * to be output to the ring gear shaft 32a as the drive shaft based on the accelerator opening Acc and the vehicle speed V, and supplies the engine 22 with the following equation (1). Calculate the required power P * required. In Equation (1), “Gr” is the gear ratio of the reduction gear 35, and “Loss” is a loss. Next, the inertia moment I of the inertial system composed of the engine 22 and the motor MG1 viewed from the engine 22 is calculated according to the following equation (2), and the inertia (torque of the system composed of the engine 22 and the motor MG1 according to the following equation (3): ) Calculate Ti. However, “Im1” in the equation (2) is the inertia coefficient of the motor MG1, “Ie” is the inertia coefficient of the engine 22, “ρ” is the gear ratio of the planetary gear 30, and “previous Ne” in the equation (3) is this The engine speed “t1” input at the previous execution of the routine is “t1”. Subsequently, when setting the estimated power Pest that is the power estimated to be output from the engine 22, a reflection rate α that is a ratio of reflecting the inertia Ti to the estimated power Pest is set. A detailed procedure for setting the reflection rate α will be described later. If the inertia Ti and the reflection rate α are set, the estimated power Pest of the engine 22 is calculated according to the following equation (4). However, “previous Tm1 *” in the equation (4) is a torque command of the motor MG1 set at the previous execution of this routine.

P * = Tr * ・ Nm2 / Gr-Pb * + Loss (1)
I = ((1 + ρ) / ρ) ²・ Im1 + Ie (2)
Ti = I ・ (Ne-previous Ne) / t1 (3)
Peest = (-(1 + ρ) / ρ ・ previous Tm1 * + Ti ・ α) ・ Ne (4)

  Next, the drive shaft power Pr, which is the power currently output to the ring gear shaft 32a as the drive shaft, is calculated according to the following equation (5), and the temporary power of the power allowed for the output of the engine 22 is calculated according to the following equation (6). The temporary upper limit power Pemaxtmp which is a value is calculated. However, “previous Tr *” in equation (5) is the required torque set at the previous execution of this routine. Then, using the calculated temporary upper limit power Pemaxtmp and the estimated power Peest, the upper limit power Pemax, which is the power allowed for the output of the engine 22, is calculated by the following equation (7), and the upper limit power calculated by the following equation (8): The target power Pe * to be output from the engine 22 is set by limiting the required power P * with Pemax. Here, Expression (7) is a relational expression in feedback control. In Expression (7), “k1” in the second term on the right side is the gain of the proportional term, and “k2” in the third term on the right side is the integral term. Is the gain.

Pr = Previous Tr * ・ Nm2 / Gr (5)
Pemaxtmp = Pr-Win (6)
Pemax = Pemaxtmp + k1 (Pemaxtmp-Peest) + k2∫ (Pemaxtmp-Peest) dt (7)
Pe * = min (P *, Pemax) (8)

  When the target power Pe * of the engine 22 is set in this manner, the target rotational speed Ne * and the target torque Te of the engine 22 are set based on the predetermined operation line and the set target power Pe * for operating the engine 22 efficiently. * Is set and transmitted to the engine ECU 24. Subsequently, the target rotational speed Nm1 * of the motor MG1 is calculated according to the following equation (9) using the target rotational speed Ne *. Further, torque command Tm1 * of motor MG1 is set according to the following equation (10) based on target rotation speed Nm1 * and current rotation speed Nm1. Expression (10) is a relational expression in feedback control for rotating the motor MG1 at the target rotational speed Nm1 *, where “k3” in the expression (10) is a proportional term gain and “k4” is an integral term. Is the gain. If torque command Tm1 * for motor MG1 is set, provisional motor torque Tm2tmp, which is a provisional value of torque to be output from motor MG2, is calculated according to the following equation (11). Then, torque limits Tmax and Tmin as upper and lower limit values of torque that may be output from the motor MG2 are calculated according to the following equations (12) and (13), and the torque that is the target torque of the motor MG2 is calculated according to the following equation (14): Set command Tm2 *. Then, the set torque commands Tm1 * and Tm2 * are transmitted to the motor ECU 40.

Nm1 * = Ne * ・ (1 + ρ) / ρ-Nm2 / (Gr ・ ρ) (9)
Tm1 * =-ρ / (1 + ρ) ・ Te * + k3 ・ (Nm1 * -Nm1) + k4 ・ ∫ (Nm1 * -Nm1) dt (10)
Tm2tmp = (Tr * + Tm1 * / ρ) / Gr (11)
Tmax = (Wout-Tm1 * ・ Nm1) / Nm2 (12)
Tmin = (Win-Tm1 * ・ Nm1) / Nm2 (13)
Tm2 * = max (min (Tm2tmp, Tmax), Tmin) (14)

  The engine ECU 24 that has received the target rotational speed Ne * and the target torque Te * controls the intake air amount and the fuel injection control of the engine 22 so that the engine 22 is operated according to the target rotational speed Ne * and the target torque Te *. Execute ignition control. The motor ECU 40 that receives the torque commands Tm1 * and Tm2 * controls the inverters 41 and 42 based on the torque commands Tm1 * and Tm2 *. By such control, the hybrid vehicle 20 of the embodiment can travel by outputting a torque based on the required torque Tr * corresponding to the accelerator opening Acc to the ring gear shaft 32a.

  Next, a procedure for setting the inertia reflection rate α will be described. FIG. 2 is an explanatory diagram showing an example of an inertia reflection rate setting map. When setting the reflection rate α, the hybrid ECU 70 first calculates an average estimated power Peave, which is an average value of the estimated power Peest calculated during, for example, the last three executions of the engine operation drive control routine. Subsequently, the estimated power fluctuation amount ΔPave is calculated by subtracting the average estimated power Peave calculated at the previous execution of the engine operation drive control routine from the calculated average estimated power Peave. As illustrated in FIG. 2, the reflection rate α is set to the first value α1 when the calculated estimated power fluctuation amount ΔPave is less than a predetermined reference value ΔPeref, and the estimated power fluctuation amount ΔPave is When the value is equal to or greater than the reference value ΔPeref, the second value α2 that is larger than the first value α1 is set. The estimated power fluctuation amount ΔPave may be calculated by subtracting the average estimated power Peave calculated at the time of executing the engine operation drive control routine a plurality of times before the latest average estimated power Peave, or engine operation It may be calculated by subtracting the estimated power Peest calculated at the previous execution of the routine from the estimated power Peest calculated at the previous execution of the hour drive control routine.

  In the hybrid vehicle 20 of the embodiment described above, the average estimated power Peave, which is the average value of the estimated power Peest of the engine 22 calculated during the last three executions of the engine operation drive control routine, for example, is calculated, and the calculated average The estimated power fluctuation amount ΔPave is calculated by subtracting the average estimated power Peave calculated at the previous execution of the routine from the estimated power Peave. When the calculated estimated power fluctuation amount ΔPave is less than the predetermined reference value ΔPeref, the reflection rate α Is set to the first value α1, and when the estimated power fluctuation amount ΔPave is equal to or larger than the reference value ΔPeref, the reflection rate α is set to a second value α2 that is larger than the first value α1. As described above, when the estimated power fluctuation amount ΔPaveave, which is the fluctuation amount of the average estimated power Peave based on the estimated power Pest of the engine 22, is small and the influence of the inertia Ti is small, the first value α1 is set to be relatively small as the reflection rate α. By doing so, it is possible to accurately calculate the estimated power Peest of the engine 22 without excessively reflecting the inertia Ti, and to control the engine 22 more appropriately based on the calculated estimated power Peest. When the estimated power fluctuation amount ΔPaveave, which is the fluctuation amount of the average estimated power Peave based on the estimated power Peest of the engine 22, is large and the influence of the inertia Ti is large, the reflection rate α is set to a second value larger than the first value α1. By setting to α2, the estimated power Peest of the engine 22 can be calculated with higher accuracy by reflecting the inertia Ti more appropriately, and the upper limit power Pemax of the engine 22 can be set more appropriately. By operating the engine 22 within the range of the set upper limit power Pemax, even if the power of the engine 22 suddenly increases, such as during sudden acceleration, the battery is prevented from outputting more power than necessary from the engine 22. 50 overcharge can be suppressed more appropriately.

  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 “internal combustion engine”, the motor MG1 corresponds to “first electric motor”, the planetary gear 30 corresponds to “power distribution means”, and the motor MG2 corresponds to “second electric motor”. The hybrid ECU that calculates the required power P * required for the engine 22 corresponds to the “power storage unit”, the battery ECU 52 that sets the input limit Win of the battery 50 corresponds to the “allowable charging power setting unit”. Corresponds to “required power setting means”, and calculates the inertia moment I of the inertial system composed of the engine 22 and the motor MG1 as viewed from the engine 22, and calculates the inertia (torque) Ti of the system composed of the engine 22 and the motor MG1. The hybrid ECU 70 that corresponds to the “inertia calculation means” calculates the estimated power Pest of the engine 22. The hybrid ECU 70 that corresponds to the “estimated power calculation means”, the drive shaft power Pr as the power currently output to the ring gear shaft 32a as the drive shaft, the input limit Win of the battery 50, and the calculated estimated power Pest of the engine 22 The hybrid ECU 70 that sets the upper limit power Pemax, which is the power allowed for the output of the engine 22 based on the above, corresponds to the “upper limit power setting means”, and the required power P * is limited by the upper limit power Pemax and output from the engine 22. The hybrid ECU 70 for setting the target power Pe * to be equivalent to the “target power setting means”. The target power Pe * is output from the engine 22 and the torque based on the required torque Tr * required for traveling is expressed by the ring gear shaft. 32a and the engine 22 and the motor to be output to A combination of the hybrid ECU 70, the engine ECU 24, and the motor ECU 40 that controls the G1 and the motor MG2 corresponds to a “control unit”, and the estimated power of the engine 22 calculated during, for example, the last three execution control routines during engine operation. The average estimated power Peave, which is the average value of the Peest, is calculated, the estimated power fluctuation amount ΔPave is calculated by subtracting the average estimated power Peave calculated at the previous execution of the routine from the calculated average estimated power Peave, and the calculated estimated power When the fluctuation amount ΔPave is less than the predetermined reference value ΔPeref, the reflection rate α is set to the first value α1, and when the estimated power fluctuation amount ΔPave is equal to or greater than the reference value ΔPeref, the reflection rate α is set to the first value α1. Second value α2 that is greater than value α1 Hybrid ECU70 for setting corresponds to the "reflection ratio setting means". However, 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. In other words, the examples are merely specific examples of the invention described in the column for means for solving the problem, and the interpretation of the invention described in the column for means for solving the problem is described in the description of the column. Should be done on the basis.

  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 is applicable to the hybrid vehicle manufacturing industry.

  20 hybrid vehicle, 22 engine, 24 electronic control unit (engine ECU) for engine, 26 crankshaft, 28 damper, 30 planetary gear, 31 sun gear, 32 ring gear, 32a ring gear shaft, 34 carrier, 35 reduction gear, 37 gear mechanism, 38 Differential gear, 39a-39b wheel, 40 motor electronic control unit (motor ECU), 41, 42 inverter, 43, 44 rotational position detection sensor, 50 battery, 52 battery electronic control unit (battery ECU), 54 power line, 70 Electronic control unit for hybrid (hybrid ECU), 84 accelerator pedal position sensor, 87 vehicle speed sensor, MG1, MG2 motor.

Claims (1)

An internal combustion engine, a first electric motor capable of inputting / outputting power, an output shaft of the internal combustion engine, a rotation shaft of the first electric motor, and a drive shaft are connected to three axes. Power distribution means for inputting / outputting power based on input / output power to the remaining shaft, a second motor capable of inputting / outputting power to / from the drive shaft, and power exchange with the first and second motors Power storage means, allowable charge power setting means for setting allowable charge power that is power allowed for charging of the power storage means, required power setting means for setting required power required for the internal combustion engine, and the internal combustion engine And inertia calculating means for calculating an inertia of the system consisting of the internal combustion engine and the first electric motor based on a product of a moment of inertia of the system consisting of the first electric motor and a time derivative of the rotational speed of the internal combustion engine; 1 electric Estimated power calculating means for calculating estimated power that is estimated to be output from the internal combustion engine based on the torque output from the engine, the rotational speed of the internal combustion engine, and the calculated inertia, and the drive shaft Upper limit power setting means for setting an upper limit power that is allowed for the output of the internal combustion engine based on the output drive shaft power, the set charge allowable power of the power storage means, and the calculated estimated power And target power setting means for setting target power to be output from the internal combustion engine by limiting the set required power with the set upper limit power, and the set target power is output from the internal combustion engine. And the internal combustion engine and the first and second electric motors so that torque based on required torque required for traveling is output to the drive shaft. A hybrid vehicle and a control means for controlling,
When the fluctuation amount of the estimated power is less than a predetermined reference value, when calculating the estimated power, a reflection rate that is a ratio of reflecting the calculated inertia in the estimated power is set to a first value. A hybrid vehicle comprising reflection rate setting means for setting the reflection rate to a second value larger than the first value when the amount of fluctuation of the estimated power is greater than or equal to the reference value.

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