JP2013244875A - Vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent drop of power performance beforehand in a vehicle provided with an engine and a motor.SOLUTION: An ECU (200) determines that the load factor of a motor is 100% when motor detection temperature T is less than a load restriction starting temperature TR, and it decreases the load factor of the motor to less than 100% when it is not (220). The ECU calculates motor estimated temperature in the future (predetermined period later) by using NAVI information during EV travelling using motor power without engine power, and when the motor estimated temperature in the future is lower than the load restriction starting temperature TR, EV travelling inhibition temperature TP is set to "temperature T1" slightly lower than TR, and when it is not, EV travelling inhibition temperature TP is set to "temperature T2" lower than T1 (230). The ECU changes over to HV travelling using both powers of engine and motor when the motor detection temperature T exceeds TP during EV travelling.

Description

  The present invention relates to a vehicle including an engine and a motor.

  In JP2010-226880A (Patent Document 1), in an electric vehicle in which a driving motor is arranged on each of four wheels, a use plan of each motor is created using information from a navigation device, A technique is disclosed in which the temperature rise level of each motor is prevented from exceeding the upper limit value by controlling each motor based on the use plan.

JP 2010-226880 A JP 2010-124594 A JP 2010-115053 A

  By the way, in a hybrid vehicle including an engine and a motor, it is possible to switch between EV traveling that uses the power of the motor without using the power of the engine and HV traveling that uses the power of both the engine and the motor. There is something. In such a hybrid vehicle, the thermal load (heat generation amount) of the motor can be reduced by switching from EV traveling that travels only by the power of the motor to HV traveling that can obtain engine assistance.

  However, when control is performed to limit the load factor of the motor when the motor temperature exceeds a predetermined load limit start temperature, if EV running is performed until just before the motor temperature reaches the load limit start temperature, Even when switching to HV traveling, the motor temperature does not decrease immediately due to thermal overshoot. Therefore, the motor temperature exceeds the load limit start temperature and the load factor of the motor is limited, and the power performance of the vehicle may be reduced.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to prevent a reduction in power performance of a vehicle in a vehicle including an engine and a motor.

  A vehicle according to the present invention includes an engine and a motor that generate driving force of the vehicle, a navigation device that acquires vehicle travel route information, a sensor that detects the temperature of the motor, and a control device that controls the engine and the motor. Prepare. When the temperature detected by the sensor exceeds the motor travel prohibition temperature during motor travel that travels using the power of the motor without using the power of the engine, the control device uses the power of both the engine and the motor from the motor travel. Switch to hybrid driving. The control device limits the load factor of the motor when the detected temperature exceeds the load limit start temperature. The control device calculates the predicted temperature of the motor after a predetermined time using the information from the navigation device during motor traveling, and when the predicted temperature is lower than the load limit start temperature, the motor traveling prohibition temperature is set to the first temperature. If the predicted temperature is higher than the load limit start temperature, the motor travel prohibition temperature is changed to a second temperature lower than the first temperature and lower than the load limit start temperature.

  ADVANTAGE OF THE INVENTION According to this invention, in the vehicle provided with the engine and the motor, the power performance fall of a vehicle can be prevented beforehand.

1 is an overall block diagram of a vehicle. It is a functional block diagram of ECU. It is a figure which shows an example of the change aspect of the motor detection temperature.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

  FIG. 1 is an overall block diagram of a vehicle 1 according to an embodiment of the present invention. The vehicle 1 is a so-called plug-in hybrid vehicle. The vehicle 1 includes an engine 10, a first MG (Motor Generator) 20, a second MG 30, a power split device 40, a speed reducer 50, a PCU (Power Control Unit) 60, a battery 70, drive wheels 80, ECU (Electronic Control Unit) 200. The vehicle 1 further includes a charging port 110 and a charger 300. The present invention can also be applied to a normal hybrid vehicle that does not include the charging port 110 and the charger 300.

  Engine 10, first MG 20 and second MG 30 are connected via power split device 40. The vehicle 1 travels with driving force output from at least one of the engine 10 and the second MG 30. The power generated by the engine 10 is divided into two paths by the power split device 40. That is, one is a path that is transmitted to the drive wheels 80 via the speed reducer 50, and the other is a path that is transmitted to the first MG 20.

  Engine 10 is controlled by a control signal from ECU 200. First MG 20 and second MG 30 are AC motors, for example, three-phase AC synchronous motors. First MG 20 generates power using the power of engine 10 divided by power split device 40. Second MG 30 generates a driving force using at least one of the electric power stored in battery 70 and the electric power generated by first MG 20. Then, the driving force of the second MG 30 is transmitted to the driving wheels 80 via the speed reducer 50. When the vehicle is braked, the second MG 30 is driven by the drive wheels 80 via the speed reducer 50, and the second MG 30 operates as a generator. Thereby, 2nd MG30 functions also as a regenerative brake which converts kinetic energy of vehicles into electric power. The regenerative power generated by second MG 30 is stored in battery 70.

  Power split device 40 includes a planetary gear including a sun gear, a pinion gear, a carrier, and a ring gear. The pinion gear engages with the sun gear and the ring gear. The carrier supports the pinion gear so as to be capable of rotating, and is connected to the crankshaft of the engine 10. The sun gear is connected to the rotation shaft of the first MG 20. The ring gear is connected to the rotation shaft of second MG 30 and speed reducer 50. As described above, the engine 10, the first MG 20, and the second MG 30 are connected via the power split device 40 including the planetary gears, so that the engine rotation speed, the first MG rotation speed, and the second MG rotation speed are represented in the collinear diagram. The relationship is connected by a straight line.

  PCU 60 is controlled by a control signal from ECU 200. PCU 60 converts the DC power stored in battery 70 into AC power that can drive first MG 20 and second MG 30 and outputs the converted AC power to first MG 20 and / or second MG 30. Thereby, first MG 20 and / or second MG 30 are driven by the electric power stored in battery 70. Further, the PCU 60 converts the AC power generated by the first MG 20 and / or the second MG 30 into DC power that can charge the battery 70 and outputs the DC power to the battery 70. Thereby, battery 70 is charged with the electric power generated by first MG 20 and / or second MG 30.

  The battery 70 is a direct current power source that stores electric power for driving the first MG 20 and / or the second MG 30 and includes, for example, a secondary battery such as nickel metal hydride or lithium ion. The output voltage of the battery 70 is about 200V, for example. Note that a large-capacity capacitor can also be used as the battery 70.

  Charging port 110 is a power interface for receiving power from external power supply 400 (hereinafter simply referred to as “external power”). Charging port 110 is configured to be connectable to charging connector 410 connected to external power supply 400.

  Charger 300 is electrically connected to charging port 110 and battery 70. Based on a control signal from ECU 200, charger 300 converts external power received by charging port 110 into electric power that can be charged in battery 70, and outputs the electric power to battery 70. Thereby, the battery 70 is charged by the external power.

Further, the vehicle 1 includes a temperature sensor 11 and a navigation device 12.
Temperature sensor 11 detects the temperature of second MG 30 and outputs the detection result to ECU 200. The temperature sensor 11 may be configured to include, for example, a thermistor (a resistor whose electric resistance changes with respect to a temperature change). Hereinafter, the temperature of the second MG 30 detected by the temperature sensor 11 is referred to as “motor detection temperature T”.

  The navigation device 12 calculates information (hereinafter also referred to as “NAVI information”) such as the travel route to the destination set by the user, the travel time, and the average speed, and outputs the calculation result to the ECU 200.

  The ECU 200 includes a CPU (Central Processing Unit) and a memory (not shown), and is configured to execute predetermined arithmetic processing based on information stored in the memory and information from each sensor and the like.

  ECU 200 travels using the EV travel mode in which the motor travels using the power of second MG 30 without using the power of engine 10 (hereinafter referred to as “EV travel”) and the power of both engine 10 and second MG 30. The vehicle 1 is caused to travel in one of the travel modes, ie, the HV travel mode for performing hybrid travel (hereinafter referred to as “HV travel”).

  During EV travel, the engine 10 is not assisted and travel is performed with the power of the second MG 30, so the thermal load (heat generation amount) of the second MG 30 tends to be relatively large. On the contrary, during the HV traveling, the assist by the engine 10 is obtained, so that the thermal load of the second MG 30 tends to be relatively small. Considering this point, when the motor detection temperature T exceeds the EV travel prohibition temperature TP during EV travel, the ECU 200 switches from EV travel to HV travel. Thereby, the thermal load of 2nd MG30 is relieved.

  Regardless of whether the vehicle is traveling in EV or HV, if the temperature of the second MG 30 exceeds the allowable temperature (the upper limit value of the temperature that normally operates), traveling using the power of the second MG 30 becomes impossible. Considering this point, the ECU 200 determines whether the load factor of the second MG 30 (hereinafter referred to as “motor load”) when the detected motor temperature T is lower than the predetermined load limit start temperature TR regardless of whether the vehicle is traveling in EV or HV. Control) is set to 100%, and when the detected motor temperature T is equal to or higher than the load limit start temperature TR, the output of the second MG 30 is limited by lowering the motor load ratio to less than 100% according to the detected motor temperature T. (Hereinafter referred to as “load factor limiting control”).

  In the vehicle 1 having the above-described configuration, when the EV travel is performed until the motor detection temperature T reaches the load limit start temperature TR, the motor detection temperature T is increased due to thermal overshoot even if the motor detection temperature T is subsequently switched to the HV travel. It does not decrease immediately but increases for a while. For this reason, the motor detection temperature T exceeds the load limit start temperature TR, and the load factor limit control described above may be started, and the power performance of the vehicle may be reduced.

  Therefore, ECU 200 according to the present embodiment variably controls EV travel prohibition temperature TP in accordance with NAVI information. Specifically, ECU 200 uses NAVI information and motor detection temperature T to calculate a predicted temperature of second MG 30 after a predetermined time has elapsed (hereinafter referred to as “future motor predicted temperature”). Then, when the predicted motor temperature in the future is higher than the load limit start temperature TR, the ECU 200 changes the EV travel prohibition temperature TP to a low value in advance. Thereby, it is possible to switch from EV traveling to HV traveling at an early stage in anticipation of thermal overshoot.

  FIG. 2 is a functional block diagram of ECU 200. Each functional block shown in FIG. 2 may be realized by hardware or software.

  ECU 200 includes an operation planning unit 210, a load limit control unit 220, and an EV travel prohibition temperature changing unit 230.

  The operation plan unit 210 creates an operation plan to the destination based on the NAVI information (such as setting of the EV travel section and the HV travel section), and predicts the load of the second MG 30 to the destination based on the operation plan (hereinafter referred to as “the travel plan”). Simply referred to as “motor load prediction”).

  The load limit control unit 220 performs the load factor limit control described above based on the motor detected temperature T. That is, when the motor detection temperature T is lower than the load limit start temperature TR, the motor load factor is 100%. When the motor detection temperature T is equal to or higher than the load limit start temperature TR, the motor load factor is higher as the motor detection temperature T is higher. Is reduced below 100%.

  The EV travel prohibition temperature changing unit 230 calculates the above-described future motor predicted temperature based on the motor detection temperature T detected by the temperature sensor 11 and the motor load prediction calculated from the NAVI information. Then, the EV travel prohibition temperature changing unit 230 sets the EV travel prohibition temperature TP to “temperature T1” when the future predicted motor temperature is lower than the load limit start temperature TR, and the future motor predicted temperature starts the load limit. When the temperature is higher than the temperature TR, the EV travel prohibition temperature TP is set to “temperature T2”. Here, the “temperature T1” is set to a value slightly lower than the load limit start temperature TR. On the other hand, “temperature T2” is set to a value lower than the temperature T1 by a predetermined temperature in consideration of thermal overshoot. As described above, when the predicted motor temperature in the future is higher than the load limit start temperature TR, the EV travel prohibition temperature TP is lowered to “temperature T2” in advance. Thereby, the transition time from EV traveling to HV traveling can be advanced in advance in anticipation of thermal overshoot. Therefore, even if thermal overshoot actually occurs after the transition to HV traveling, the detected motor temperature T does not exceed the load limit start temperature TR, and a rapid load factor limit (power performance degradation) due to the load factor limit control can be suppressed.

FIG. 3 is a diagram illustrating an example of how the motor detection temperature T changes.
Prior to time t1, this is a period in which the predicted future motor temperature is determined to be lower than the load limit start temperature TR, and the EV travel prohibition temperature TP is set to “temperature T1”.

  When it is determined that the predicted motor temperature in the future is equal to or higher than the load limit start temperature TR at time t1, the EV travel prohibition temperature TP is lowered from the temperature T1 to the “temperature T2”. Therefore, after that, at time t2 when the detected motor temperature T reaches the temperature T2, the EV traveling is switched to the HV traveling. Although the thermal load of the second MG 30 is reduced after the HV traveling switching, the motor detection temperature T increases without decreasing due to the thermal overshoot for a while. In the present embodiment, EV travel prohibition temperature TP is lowered to “temperature T2” in advance in view of such thermal overshoot. As a result, at time t2 when the detected motor temperature T reaches “temperature T2”, the vehicle is quickly switched to HV traveling. However, since the temperature difference between the temperature T2 and the load limit start temperature TR is sufficiently secured, the HV traveling is performed. Even if a thermal overshoot actually occurs after the transition, the motor detection temperature T does not exceed the load limit start temperature TR. Therefore, it is possible to suppress sudden load factor limitation (power performance degradation) due to load factor limitation control.

  The dashed-dotted line shown in FIG. 3 shows the change aspect of the motor detection temperature T at the time of fixing EV running prohibition temperature TP to "temperature T1" as a comparative example. In this comparative example, switching to HV traveling is performed at time t3 when the motor detection temperature T reaches the temperature T1, but since the temperature difference between the temperature T1 and the load limit start temperature TR is not sufficiently ensured, the HV After the travel switching, there is a problem that the motor detection temperature T exceeds the load limit start temperature TR due to thermal overshoot, and the load factor limit control is started and the power performance of the vehicle is deteriorated. In the present embodiment, such a problem can be avoided.

  As described above, the ECU 200 according to the present embodiment calculates the future predicted motor temperature using the NAVI information, and if the predicted future motor temperature is higher than the load limit start temperature TR, the overshoot of heat is performed. The EV travel prohibition temperature TP is changed to a low value in advance. Thereby, it is possible to switch from EV traveling to HV traveling at an early stage, and it is possible to prevent motor load limitation (power performance degradation) due to thermal overshoot.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  DESCRIPTION OF SYMBOLS 1 Vehicle, 10 Engine, 11 Temperature sensor, 12 Navigation apparatus, 20 1st MG, 30 2nd MG, 40 Power split device, 50 Reducer, 70 Battery, 80 Driving wheel, 110 Charging port, 200 ECU, 210 Operation plan part, 220 load limit control unit, 230 EV travel prohibition temperature changing unit, 300 charger, 400 external power supply, 410 charging connector.

Claims (1)

An engine and a motor for generating a driving force of the vehicle;
A navigation device for acquiring vehicle travel route information;
A sensor for detecting the temperature of the motor;
A control device for controlling the engine and the motor,
When the temperature detected by the sensor exceeds the motor travel prohibition temperature during motor travel that travels using the power of the motor without using the power of the engine, the control device starts from the motor travel to the engine and the motor. Switch to hybrid driving that uses both of the power,
When the detected temperature exceeds the load limit start temperature, the control device limits the load factor of the motor,
The control device calculates a predicted temperature of the motor after a predetermined time using information from the navigation device during the motor traveling, and the motor traveling when the predicted temperature is lower than the load limit start temperature. A prohibition temperature is set to a first temperature, and when the predicted temperature is higher than the load limit start temperature, the motor travel prohibition temperature is set to a second temperature lower than the first temperature and lower than the load limit start temperature. Change the vehicle.

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