JP2010285092A - Start-up determination device for hybrid vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a start-up determination device for hybrid vehicle with high temperature-estimation accuracy in an internal combustion engine 35. <P>SOLUTION: This start-up determination device for hybrid vehicle includes: a battery temperature measuring part 42 for measuring a temperature of a high-voltage battery 31 for supplying electric power to an electric motor 33; a time estimation part for estimating a stop time until restarting a vehicle system after stopped, based on the temperature of the high-voltage battery 31 measured by the battery temperature measuring part 42 when stopping the vehicle system of the hybrid vehicle, and based on the temperature of the high-voltage battery 31 measured by the battery temperature measuring part 42 when restarting the vehicle system; and a temperature estimation part for estimating a temperature of the internal combustion engine 35, based on the stop time estimated by the time estimation part, in the hybrid vehicle using the internal combustion engine 35 and the electric motor 33 for running. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a hybrid vehicle start-up determination device that determines start permission of a vehicle system based on the temperature of a high-power battery that supplies power to the motor in a hybrid vehicle that travels in combination with an internal combustion engine and a motor.

  Conventionally, when the engine is started at a low temperature, a higher starting torque is required as compared with the case of normal temperature driving due to an increase in the oil viscosity of the engine. However, generally, the battery output at a low temperature is smaller than that at a normal temperature, which may hinder engine starting.

  Therefore, in Patent Document 1, when the engine temperature detected by the engine temperature sensor and the battery temperature detected by the battery temperature sensor are lower than a predetermined temperature, the hybrid vehicle warms the engine and the battery using the heating means. Has been proposed. According to Patent Document 1, it is said that cold startability can be improved without using an emergency starter motor at the time of cold start of the engine.

JP 2001-234840 A

  By the way, in the hybrid vehicle which employ | adopted the idle stop, since a battery output falls at low temperature, it is necessary to depend on an engine output. However, since the engine friction is large at low temperatures, the battery output is low and the cranking torque is limited, and the engine is difficult to start, the vehicle system is permitted to start after the engine has been reliably started.

  Here, the low temperature is determined by the cooling water temperature of the engine. However, if this engine water temperature sensor system is broken, a higher fail-safe value (F / S value) is applied as it is. In some cases, the determination cannot be made, and the vehicle system activation permission is erroneously determined. An attempt to start the engine with a large amount of engine friction may occur. In this case, since the high-power battery energy (drive motor power) is utilized, the motor load continuously increases more than necessary, which may cause a problem that the high-power battery runs out and cannot be restarted.

  The present invention has been made in view of such a conventional problem, and an object of the present invention is to provide a start determination device for a hybrid vehicle having high temperature estimation accuracy of an internal combustion engine.

  A feature of the present invention is that, in a hybrid vehicle that travels by combining an internal combustion engine and an electric motor, a battery temperature measuring unit that measures the temperature of a high-power battery that supplies electric power to the electric motor, and a battery when the vehicle system of the hybrid vehicle is stopped Based on the temperature of the high-power battery measured by the temperature measurement unit and the temperature of the high-power battery measured by the battery temperature measurement unit when the vehicle system is started again, the stop time from when the vehicle system is stopped to when it is started again is calculated. The gist of the invention is a hybrid vehicle start-up determination device including a time estimation unit to be estimated and a temperature estimation unit to estimate the temperature of the internal combustion engine based on the stop time estimated by the time estimation unit.

  According to the feature of the present invention, even if a water temperature sensor for measuring the temperature of the cooling water of the internal combustion engine fails, an estimated value that can substitute the sensor output can be obtained with high accuracy. Alternatively, whether or not the internal combustion engine can be started under a low temperature condition can be appropriately determined even when the above-described water temperature sensor is not provided.

  In the feature of the present invention, the start determination device for a hybrid vehicle further includes an outside air temperature measurement unit that measures the outside air temperature of the hybrid vehicle, and the time estimation unit estimates the air temperature in consideration of the outside air temperature measured by the outside air temperature measurement unit. Correction may be made to the stopped time. As a result, the temperature drop of the high-power battery is affected by the temperature difference from the cooling condition (environmental temperature), so that the temperature estimation accuracy of the internal combustion engine can be improved by taking this into consideration.

  In the characteristics of the present invention, the time estimation unit may estimate a longer stop time as the charge / discharge integrated value of the high-power battery used during the previous vehicle system activation is larger. In this way, by taking into account the specific heat of the high-power battery and the internal temperature rise delay, the temperature estimation accuracy of the internal combustion engine based on the high-power battery temperature change can be further improved.

  As described above, according to the present invention, it is possible to provide a start determination device for a hybrid vehicle with high temperature estimation accuracy of the internal combustion engine.

It is a block diagram which shows the main structures of the hybrid vehicle concerning embodiment of this invention. It is a flowchart which shows an example of operation | movement of the starting judgment apparatus for hybrid vehicles of FIG. It is a graph which shows an example of the relationship between the temperature rise of the high-power battery 31 after ignition off, and the charge / discharge integrated amount (absolute value) of the high-power battery 31. It is a graph which shows an example of the relationship between the temperature rise of the high-power battery 31 after the ignition is turned off and the required time (temperature rise required time) from when the ignition is turned off until the high-power battery 31 reaches the maximum battery temperature. It is a graph which shows an example of the relationship between the deterioration state of the high-power battery 31, and the correction amount of the temperature rise of the high-power battery 31 after the ignition is turned off. It is a graph which shows an example of the relationship between the quantity which multiplied "high electric battery cooling time" by "high electric battery cooling wind temperature", and the correction amount of the temperature rise of the high electric battery 31 after ignition off. It is a graph which shows an example of the relationship between "outside temperature" and the correction amount of the temperature rise of the high-power battery 31 after ignition off. It is a graph which shows an example of the relationship between the temperature rise of the high-power battery 31 after the ignition is turned off, “outside air temperature”, and “required cooling time”. It is a graph which shows an example of the relationship between ignition off required time (stop time), "outside temperature", and "engine water temperature". It is a figure which shows an example of the timing chart concerning embodiment of this invention and a comparative example.

  Embodiments of the present invention will be described below with reference to the drawings. In the description of the drawings, the same parts are denoted by the same reference numerals.

With reference to FIG. 1, main configurations of a hybrid vehicle and a hybrid vehicle activation determination device according to an embodiment of the present invention will be described. In FIG. 1, a thin broken line indicates a strong electric connection, a thin solid line indicates a weak electric connection, a thick solid line indicates a power connection, and a one-dot broken line indicates a hydraulic connection.

  The hybrid vehicle is a vehicle that travels in combination with an engine 35 as an example of an internal combustion engine and a drive motor 33 as an example of an electric motor, and supports the CPU 11 that controls the entire vehicle and the start of the engine 35. A generator 34, a high-power battery 31 that supplies power to the drive motor 33, an inverter 32 that supplies electric energy of the high-power battery 31 to the drive motor 33 according to the generated torque and rotation speed of the engine 35, and the CPU 11 An auxiliary battery 12 that provides an operating power source, a DC / DC converter 43 that converts the energy of the high-power battery 31 to about 12 V and supplies the battery to the auxiliary battery 12, a water temperature sensor 44 that detects the temperature of the engine 35, and the high-power battery 31 A battery temperature sensor (battery temperature measuring unit) 42 for detecting the temperature of the For the cooling air temperature sensor 45 that detects the temperature of the cooling air that cools the terry 31, the outside air temperature sensor (outside air temperature measuring unit) 46 that detects the temperature of the environment in which the vehicle system is placed, and the tires 51a to 51d Mechanical brakes 22a to 22d, a brake actuator 21, and a transmission (T / A) 36 having a planetary gear mechanism.

  The CPU 11 monitors various states including the state of charge (SOC), temperature, and deterioration state of the high-power battery 31, and calculates the amount of power that can be input / output according to these states. Then, by controlling the inverter 32 based on the calculated electric energy, the drive motor 33 and the generator 34 are operated, and the engine 35 is controlled. The driving force distribution between the driving motor 33 and the engine 35 is also controlled. Further, the CPU 11 considers the regenerative braking force by the drive motor 33 and transmits a braking force calculation command value generated by the mechanical brakes 22 a to 22 d to the brake actuator 21. The CPU 11 is basically based on grasping the own vehicle speed from the rotational speed of the drive motor 33. In addition, the CPU 11 monitors detection values of various sensors such as an accelerator sensor.

  The auxiliary battery 12 provides an operating power source for the CPU 11 and is supplied with power by a DC / DC converter 43 that uses the high-power battery 31 as a power source. The brake actuator 21 receives a braking force calculation command value to be generated by the mechanical brakes 22a to 22d calculated by the CPU 11, and applies a necessary hydraulic pressure to the mechanical brakes 22a to 22d accordingly.

  The mechanical brakes 22a to 22d generate a braking force according to the hydraulic pressure generated by the brake actuator 21. The high-power battery 31 assists vehicle travel by supplying power to the drive motor 33 via the inverter 32. The electric power generated by the generator 34 is recovered to the high-power battery 31 via the inverter 32. In addition, the high-power battery 31 includes a battery temperature sensor 42 that detects the temperature of the high-power battery 31, and the detected value of the battery temperature sensor 42 is transmitted to the CPU 11.

  The inverter 32 is directly controlled by the CPU 11, and supplies the electric energy of the high-power battery 31 to the drive motor 33 according to the torque and the rotational speed generated by the engine 35, and the electric energy generated by the generator 34 is supplied to the high-power battery. Return to 31. The drive motor 33, the generator 34 and the engine 35 are directly connected to a planetary gear mechanism built in the transmission 36. Therefore, the inverter 32 controls the high-power battery 31 and the generator 34 so as to keep a balance between the torque and the rotational speed in order to operate the vehicle normally.

The drive motor 33 generates drive torque independently when the vehicle speed is low. That is, in this case, the engine 35 does not generate drive torque. When the vehicle speed is high, the drive motor 33 assists the drive torque generated by the engine 35. Further, when the vehicle is decelerated, the drive motor 33 generates electric energy by performing regenerative braking. The generated electric energy is returned to the high voltage battery 31 via the inverter 32.

  The hybrid vehicle of FIG. 1 does not have a starter for starting the engine 35. The hybrid vehicle according to the embodiment of the present invention supports the start of the engine 35 by supplying electric power from the high-power battery 31 and operating the generator 34 as a motor when the engine 35 is started. During normal travel, electric energy is generated (power generation) by balancing the drive motor 33 and the engine 35, and this electric energy is returned to the high-power battery 31. Alternatively, the generated electric energy can be directly supplied to the drive motor 33. Thereby, it becomes possible to cope with rapid acceleration.

  The engine 35 is directly controlled by the CPU 11. Specifically, when the vehicle speed is high, torque is generated for driving the vehicle. Since the motor travels when the vehicle speed is low, control by the CPU 11 is unnecessary. The transmission 36 has a planetary gear mechanism. An engine 35 is directly connected to the planetary carrier, a drive motor 33 is directly connected to the internal gear (ring gear), and a generator 34 is directly connected to the sun gear (sun gear). The transmission equivalent of the conventional system is also configured inside.

  The DC / DC converter 43 converts the voltage supplied from the high voltage battery 31 to about 12 V and supplies the converted voltage to the auxiliary battery 12. The DC / DC converter 43 has the same function as an alternator in a conventional engine vehicle.

  The water temperature sensor 44 detects the temperature of the cooling water of the engine 35 and inputs this information to the CPU 11. The cooling air temperature sensor 45 detects the temperature of the cooling air that cools the high-power battery 31 and inputs this information to the CPU 11. The outside air temperature sensor 46 detects the temperature of the environment where the vehicle system is placed, and inputs this information to the CPU 11.

  With reference to FIG. 2, an example of operation | movement of the hybrid vehicle starting determination apparatus of FIG. 1 is demonstrated.

  (A) First, in step S01, the CPU 11 records vehicle information when turning off the ignition of the hybrid vehicle. Specifically, after detecting the ignition (IGN) off process, when performing the vehicle system off process, the integrated value of the amount of power charged to the high-power battery 31 and the amount of power discharged from the high-power battery 31 in this trip Record “high-power battery accumulated charge / discharge amount” indicating (absolute value). Further, the “high-power battery temperature” indicating the temperature of the high-power battery 31 is confirmed and recorded from the battery temperature sensor 42 of the high-power battery 31.

  (B) Further, the “strong battery cooling time” and the “strong battery deterioration information” after turning off the ignition from the strong battery 31 are confirmed and recorded. Further, the “engine water temperature” indicating the coolant temperature of the engine 35 is confirmed and recorded by the water temperature sensor 44. The “high-power battery cooling air temperature” indicating the temperature of the cooling air that cools the high-power battery 31 from the cooling air temperature sensor 45 is confirmed and recorded. The “outside temperature” indicating the temperature of the environment where the vehicle system is placed is confirmed and stored from the outside temperature sensor 46.

  (C) Thereafter, the process proceeds to step S03, and the CPU 11 confirms the “strong battery temperature” and the “outside temperature” when the ignition is turned on again.

(D) Proceeding to step S05, the CPU 11 estimates the stop time from when the vehicle system is stopped to when it is started again and the coolant temperature of the engine 35 (engine water temperature) from the vehicle information and various temperature information described above. To do. Specifically, the CPU 11 measures the temperature of the high-power battery 31 measured by the battery temperature sensor 42 when the vehicle system of the hybrid vehicle is stopped (when the ignition is turned off) and the battery temperature sensor 42 when the vehicle system is started again. And the temperature of the engine 35 based on the stop time estimated by the time estimation unit (estimated stop time from when the ignition is turned off to when the ignition is turned on again). It operates as a temperature estimation unit that estimates water temperature.

  (E) First, it is estimated from the “high-power battery integrated charge / discharge amount” how much the temperature rises from the “high-power battery temperature” when the ignition is turned off. As shown in FIG. 3, the higher the absolute value of the “high-power battery integrated charge / discharge amount” is, the more the high-power battery 31 generates heat. Therefore, the temperature increase amount of the high-power battery 31 after the ignition is turned off increases.

  (F) The temperature increase estimated from FIG. 3 is corrected by “strong battery cooling time” and “strong battery cooling air temperature”. For example, the temperature rise amount may be corrected with reference to the data shown in FIG. In the example of FIG. 6, when the temperature of the cooling air is low or the cooling time is long, the temperature rise is limited. Further, the temperature increase estimated from FIG. 3 is corrected by “outside air temperature”. For example, the temperature rise amount may be corrected with reference to the data shown in FIG. In the example of FIG. 7, the temperature rise is restricted when the outside air temperature is low. Further, the amount of temperature increase estimated from FIG. 3 is corrected to the side that generates heat because the internal resistance increases as the deterioration progresses, according to the “strong battery deterioration information”. For example, the temperature rise amount may be corrected with reference to the data shown in FIG. In the example of FIG. 5, the amount of heat generation increases and the temperature rises as the internal resistance deteriorates.

  (G) Next, the time required for the high-power battery 31 to reach the maximum battery temperature after the ignition is turned off from the temperature rise after the ignition turned off estimated and corrected as described above (time required for temperature rise) ). Specifically, for example, the temperature increase time may be estimated with reference to the data shown in FIG.

  (H) Next, the required time (cooling required time) from the time when the above-mentioned maximum battery temperature is reached to the time when the battery temperature is lowered at the next startup (S03) is expressed as “strong battery cooling time” and “strong battery”. It is estimated based on “cooling air temperature” and “outside air temperature”. Specifically, for example, the cooling time may be estimated with reference to the data shown in FIG. In the example of FIG. 8, the temperature difference between the maximum battery temperature and the battery temperature at the next start-up (S03) is taken on the vertical axis, and “outside air temperature” is taken on the horizontal axis. "Is higher, the cooling time is longer.

  (I) Next, the “temperature rise time” and “cooling time” are added together until the vehicle system is stopped and then restarted, that is, until the ignition is turned off and then turned on again. The stop time of Then, the “engine water temperature” is estimated based on the stop time and the “outside air temperature”. Specifically, for example, the “engine water temperature” may be estimated with reference to FIG. In FIG. 9, the horizontal axis (time required for ignition / off) corresponds to a stop time from when the vehicle system is stopped until it is started again. The lower the outside air temperature and the longer the stop time, the lower the “engine water temperature”.

  (N) Proceeding to step S07, the estimated "engine water temperature" is compared with the "high-power battery temperature" detected when the ignition is turned on again, and the engine low temperature start determination is performed based on whichever is lower.

With reference to FIG. 10, the effect by embodiment of this invention is demonstrated. As indicated by a dotted line PR in FIG. 10, the water temperature sensor 44 often has a fail-safe value (F / S value) at the time of abnormality set to a high temperature side. If the fail-safe value set on the high temperature side is applied as it is at the time of cold start, an appropriate low temperature judgment cannot be made. Then, when starting the engine 35 in a state where the engine friction is large and the high-power battery 31 is at a low temperature and the output is restricted, there is a possibility that the high-power battery 31 rises and consequently the vehicle system cannot be started. is there. On the other hand, in the embodiment of the present invention, it is possible to make an appropriate low temperature determination, and the possibility of attempting to start the engine 35 under unreasonable conditions is reduced.

  As described above, the present invention has been described by way of one embodiment, but it should not be understood that the discussion and drawings that form part of this disclosure limit the present invention. From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art. That is, it should be understood that the present invention includes various embodiments and the like not described herein. Therefore, the present invention is limited only by the invention specifying matters according to the scope of claims reasonable from this disclosure.

11 CPU
DESCRIPTION OF SYMBOLS 12 Auxiliary battery 21 Brake actuator 22a-22d Mechanical brake 31 High electric battery 32 Inverter 33 Drive motor (electric motor)
34 Generator 35 Engine (Internal combustion engine)
36 Transmission 42 Battery temperature sensor (battery temperature measurement unit)
43 DC / DC converter 44 Water temperature sensor 45 Cooling air temperature sensor 46 Outside air temperature sensor (outside air temperature measuring unit)
51a-51d tires

Claims (3)

In a hybrid vehicle that travels by combining an internal combustion engine and an electric motor, a battery temperature measuring unit that measures the temperature of a high-power battery that supplies electric power to the electric motor;
Based on the temperature of the high voltage battery measured by the battery temperature measurement unit when the vehicle system of the hybrid vehicle is stopped and the temperature of the high voltage battery measured by the battery temperature measurement unit when the vehicle system is started again, A time estimation unit for estimating a stop time from when the vehicle system is stopped until it is started again;
A start determination device for a hybrid vehicle, comprising: a temperature estimation unit that estimates a temperature of the internal combustion engine based on the stop time estimated by the time estimation unit. An outside air temperature measurement unit for measuring the outside air temperature of the hybrid vehicle;
The start determination device for a hybrid vehicle according to claim 1, wherein the time estimation unit corrects the estimated stop time in consideration of the outside air temperature measured by the outside air temperature measurement unit.   3. The hybrid vehicle start-up according to claim 1, wherein the time estimation unit estimates a longer stop time as a charge / discharge integrated value of the high-power battery used during the previous vehicle system start-up is larger. Judgment device.

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