JP2013184667A - Control device of vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a first normally open type clutch interposed between an engine and a motor generator cannot be fastened, when an air mixing rate in hydraulic oil is high at a cold start, due to the shortage of the charge of the battery before the oil pressure is started up by the oil pump.SOLUTION: Target revolution speed of an oil pump 11 is set so that this oil pressure rise time does not exceed duration of a battery 3 by detecting or presuming an air content rate of the hydraulic oil, and calculating the oil pressure rise time based on the air content rate, when at least the temperature of the hydraulic oil is low temperature of less than prescribed reference temperature.

Description

  The present invention relates to a vehicle control device, and more particularly to setting a target rotational speed of a pump such as an oil pump.

  As described in Patent Document 1, in a 1-motor 2-clutch hybrid vehicle, a clutch as a frictional engagement element is interposed between an engine as a vehicle drive source and a motor connected to the drive wheel side. Such a clutch is operated by, for example, the hydraulic pressure (hydraulic pressure) of hydraulic oil (hydraulic fluid) supplied from an oil pump driven by a motor.

JP 2008-62745 A

  For example, when a normally open type clutch that is engaged when hydraulic pressure is supplied is used as a clutch interposed between the engine and the motor, when the vehicle is started, the vehicle is driven by the power of the engine. In order to charge the battery, it is necessary to supply hydraulic pressure to the clutch to be in an engaged state.

  However, for example, when the vehicle stops from a high temperature / high rotation operation state in which the hydraulic oil is vigorously stirred, a relatively large amount of air (air) is mixed into the oil pump or the oil strainer. When the vehicle is started in such a state that the air mixing rate in the hydraulic oil is high, the volumetric efficiency decreases due to the air mixing into the hydraulic oil, so that the oil pressure by the oil pump increases, that is, the hydraulic pressure rises. Become slow. In particular, when the temperature is low, the battery output decreases and the viscosity of the hydraulic oil increases, so there is a concern that the amount of charge of the battery will be insufficient before the hydraulic pressure rises. Increasing the capacity of the battery in order to prevent such a shortage of the charged amount of the battery leads to an increase in size, weight and cost of the battery.

  The present invention has been made in view of such circumstances, and does not cause a shortage of the charge amount of the battery even when the temperature of the hydraulic fluid is low and the air mixing rate in the hydraulic fluid is high. The present invention provides a novel vehicle control device capable of operating a frictional engagement element by raising the hydraulic pressure of hydraulic fluid by a pump.

  A vehicle control apparatus according to the present invention is interposed in a power transmission system of a vehicle, and a frictional engagement element that switches between disconnection and connection of power transmission, a motor that operates by electric power supplied from a battery, and is driven by this motor And a pump for supplying hydraulic fluid to the frictional engagement element. In the present invention, the air content rate of the hydraulic fluid is detected or estimated, and at least when the temperature of the hydraulic fluid is lower than a predetermined reference temperature, the target rotational speed of the pump is set based on the air content rate. Is.

  According to the present invention, at least when the temperature of the hydraulic fluid is lower than the predetermined reference temperature, the target rotational speed of the pump is set based on the air content rate, so that the hydraulic fluid temperature is low and the hydraulic fluid inside Even in a state where the air mixing ratio is high, it is possible to operate the friction engagement element by raising the hydraulic pressure of the hydraulic fluid by the pump without causing a shortage of the charge amount of the battery.

BRIEF DESCRIPTION OF THE DRAWINGS Explanatory drawing which shows the system configuration | structure of the power transmission system of the hybrid vehicle which concerns on one Example of this invention. Explanatory drawing which shows the system configuration | structure of the control system of the hybrid vehicle of the said Example. The flowchart which shows the flow of control, such as the setting of the target rotation speed of the oil pump of the said Example. The characteristic view which shows the relationship of the target rotation speed of an oil pump with respect to battery duration and oil pressure rise time in case oil temperature is less than reference temperature. The characteristic view which shows the relationship of the target rotation speed of an oil pump with respect to battery duration and oil pressure rise time in case oil temperature is more than reference temperature.

  Hereinafter, the present invention will be described with reference to illustrated embodiments. FIG. 1 is a system configuration diagram schematically showing a power transmission system of a vehicle according to an embodiment of the present invention. This vehicle is a 1-motor 2-clutch parallel hybrid vehicle, and an engine 1 and a motor generator 2 are used in combination as a vehicle drive source. The engine 1 is a well-known spark ignition gasoline engine or compression self-ignition diesel engine. When the engine 1 is started, cranking is performed by a motor generator 2 or a starter motor 14 described later. The motor generator 2 has both a function as an electric motor that rotates by receiving power supplied from the high-power battery 3 and a function as a generator that regenerates rotational power and fills the battery 3.

  A first clutch 4 is provided between the engine 1 and the motor generator 2 to switch between connection and disconnection of power transmission between the two. The motor generator 2 is connected to a pair of drive wheels 7 via an automatic transmission 5 comprising a belt-type continuously variable transmission and a differential gear 6, and a second clutch is provided between the motor generator 2 and the automatic transmission 5. 8 is interposed. The second clutch 8 may be interposed between the automatic transmission 5 and the differential gear 6, and when the automatic transmission 5 is a stepped type, The clutch may also be used as the second clutch 8.

  In the “electric vehicle travel mode” using only the motor generator 2 as the drive source, the first clutch 4 is disengaged to disconnect the engine 1, while the engine 1 and the motor generator 2 are used together as the drive source. , The first clutch 4 is engaged and the engine 1 and the motor generator 2 are connected. The second clutch 8 is engaged or semi-engaged during traveling, and is released when the shift range is the N (neutral) range or the P (parking) range.

  A mechanical oil pump 11 driven by the rotary shaft 10 is connected to a rotary shaft 10 connecting the first clutch 4 and the motor generator 2 via a gear 12. The oil pump 11 pressurizes hydraulic fluid as hydraulic fluid stored in the oil pan 13 and supplies the hydraulic fluid to hydraulically operated parts such as the first clutch 4 and the second clutch 8 and various lubricated parts. Although not shown in the drawing, the supply of hydraulic pressure to the first clutch 4 and the switching of the release are performed by a hydraulic control valve, and the operation of the hydraulic control valve is performed by a controller such as a vehicle controller 20 or a transmission controller 21 described later. Be controlled.

  FIG. 2 is a system configuration diagram showing a control system of the hybrid vehicle. In this vehicle, a vehicle controller 20, a transmission controller (ATCU) 21, a motor controller (MC) 22, an engine controller (not shown), and the like are provided so as to be capable of bidirectional communication as controllers for storing and executing various control processes. Yes. The vehicle controller 20 controls the overall energy management of the vehicle, and as various signals indicating the vehicle operating state, the temperature of the battery 3 detected by the battery temperature sensor 23, the capacity (charge amount) of the battery 3, and the like. Is entered.

  The transmission controller 21 performs shift control of the automatic transmission 5, the oil temperature detected by the oil temperature sensor 24, the rotational speed of the power transmission system such as the rotational speed of the rotary shaft 10 detected by the rotation sensor 25, And the content rate (air content) etc. of the air contained in hydraulic fluid are input. As the oil temperature increases, the air content increases, and as the rotational speed increases, the oil is agitated and the air content increases. Therefore, the air content can be estimated based on the oil temperature and the rotational speed. However, you may comprise so that an air content rate may be detected directly using the air content rate detection apparatuses 26, such as a sensor.

  As will be described later, the vehicle controller 20 uses the oil temperature, the rotational speed of the power transmission system, and the air content ratio transmitted from the transmission controller 21 as well as the battery temperature and the battery capacity as described later. The target rotational speed of the pump 11 is calculated, converted into the target rotational speed of the motor generator 2, and output to the motor controller 22. The motor controller 22 drives and controls the motor generator 2 toward the target rotational speed via the inverter 27.

  FIG. 3 is a flowchart showing a flow of control such as setting of the target rotational speed of the oil pump 11 at the time of starting the vehicle, which is a main part of the present embodiment, and this routine is stored and executed by the vehicle controller 20 described above. .

  In step S11, it is determined whether the ignition switch (IGN) is turned off, that is, whether a vehicle stop request is detected. If a vehicle stop request is detected, the process proceeds to step S12, where the air content rate (or air content) in the hydraulic oil when the vehicle is stopped is estimated or detected (air content rate acquisition means). As described above, the air content rate is estimated based on the oil temperature of the hydraulic oil, the rotational speed of the power transmission system, or the like, or directly detected by a sensor or the like.

  In step S13, it is determined whether the ignition switch has been turned on, that is, whether a vehicle start request has been detected. This routine is complete | finished when the vehicle start request | requirement is not detected. When the vehicle is started upon detecting the vehicle start request, the process proceeds to step S14, and it is determined whether or not the oil temperature, which is the temperature of the hydraulic oil, is in a cold state that is lower than a predetermined reference oil temperature. The oil temperature is directly detected by the oil temperature sensor 24 or estimated from the temperature of the cooling water. In the case of the normal temperature state after warming up that is not in the cold state, the process proceeds to step S22, and a preset reference rotational speed Np0 (see FIG. 5) is set as the target rotational speed of the oil pump 11, as will be described later.

  On the other hand, when the oil temperature is in a cold state below the reference oil temperature, the process proceeds to step S15, and the rotation speed of the oil pump 11 is set as a variable based on the air content rate at the time of vehicle stop calculated and stored in step S12. Calculate the oil pressure rise time. This oil pressure rise time corresponds to the time required for the oil pressure to rise to a value at which the operation to the engagement side of the first clutch 4 is possible by driving the oil pump 11. This oil pressure rise time is set according to the oil temperature and the air content rate. The higher the air content rate, the lower the volumetric efficiency and the lower the discharge flow rate of the oil pump 11, so the oil pressure rise time is longer. It is set to be.

  In step S16, the friction of the oil pump 11 is calculated based on the oil temperature. Specifically, since the viscosity increases as the oil temperature decreases, the friction is calculated so that the friction of the oil pump 11 increases as the oil temperature increases. In step S17, the battery duration with respect to the rotation speed of the oil pump 11 is calculated. This battery duration corresponds to a time during which the battery 3 can operate with respect to the number of revolutions of the oil pump 11, and in step S17 in addition to the battery temperature and the capacity of the battery, that is, the state of charge (SOC). It is calculated according to the calculated friction of the oil pump 11 and the like. In step S18, the target rotation speed of the oil pump 11 is calculated based on the battery duration and the hydraulic pressure rise time with reference to the control map of FIG. 4 described later (target rotation speed calculation means).

  In step S19, driving of the motor generator 2 is started based on the target rotational speed of the oil pump 11 set in step S18 or step S22. That is, the target rotational speed of the oil pump 11 is converted into the target rotational speed of the motor generator 2, and the rotational speed control of the motor generator 2 toward the target rotational speed is started.

  In step S20, it is determined whether or not the hydraulic oil pressure has been raised. This determination is made, for example, based on whether the elapsed time from the start of starting the motor generator 2 has passed the hydraulic pressure rise time, or based on the hydraulic pressure detected or estimated by a sensor or the like. When it is determined that the hydraulic pressure has been raised, the process proceeds from step S20 to step S21, the supply of hydraulic pressure to the first clutch 4 is started, and the first clutch 4 is engaged.

  Next, the setting of the target rotation speed (reference rotation speed) of the oil pump in steps S22 and S18 will be described with reference to FIGS. 4 and 5, the region on the right side of the battery duration represented by the broken line characteristic is an NG region exceeding the battery duration, and the region on the left side of the battery duration is within the range of the battery duration. It becomes an OK area. Then, the target rotation speed is set so that the hydraulic pressure rise time is shortened within the OK region of the battery duration. That is, the target rotation speed is set so that the hydraulic pressure rise time is the shortest within a range in which the hydraulic pressure rise time is shorter than the battery duration.

  As shown in FIG. 5, under conditions that are advantageous for starting at room temperature or the like, the battery duration is longer than the hydraulic pressure rise time up to the high rotation speed region. Therefore, as shown by the arrow Y1 in FIG. 5, the hydraulic pressure rise time can be shortened by raising the target rotational speed to the reference rotational speed Np0 within a range where the battery duration is longer than the hydraulic pressure rise time. As a result, it is possible to improve the startability by shortening the time from the start of the vehicle to the engagement of the first clutch 4.

  As shown in FIG. 4, when starting at a low temperature where the oil temperature is lower than the reference oil temperature, the duration of the battery is shorter than when starting at room temperature, and in particular, in the region on the high rotation side, the hydraulic pressure rise time is the battery duration. The NG region that becomes longer than that is enlarged. For this reason, by reducing the target rotation speeds Np1 and Np2 of the oil pump so that the hydraulic pressure rise time is shorter than the battery duration, the battery is prevented from running out.

  Further, the hydraulic pressure rise time is calculated based on the air content rate, and specifically, the hydraulic pressure rise time is set to be longer as the air content rate increases. In FIG. 4, ΔT1 indicates the oil pressure rise time when the air content is low, and ΔT2 indicates the oil pressure rise time when the air content is high. As shown in FIG. 4, the hydraulic pressure rise time ΔT2 when the air content rate is high is set longer than the hydraulic pressure rise time ΔT1 when the air content rate is low (ΔT2> ΔT1). As indicated by Y2, the target rotational speed Np2 when the air content is high is set lower than the target rotational speed Np1 when the air content is low (Np2 <Np1).

  As described above, according to this embodiment, when the oil temperature is lower than the predetermined reference temperature, the oil pressure rise time is calculated based on the air content rate, and the oil pressure rise time does not exceed the battery duration. The target rotation speed of the oil pump is set as follows. Therefore, for example, when the oil temperature is low and the air mixing rate in the hydraulic oil is high, such as during cold start, as shown in FIG. 4, the oil pump reaches a range where the oil pressure rise time is shorter than the battery duration. By lowering the target rotational speed, the hydraulic pressure can be raised and the first clutch 4 can be engaged without causing battery exhaustion. Further, when the oil temperature is high as at the start of normal temperature, as shown in FIG. 5, by increasing the target rotational speed of the oil pump within a range where the oil pressure rise time does not exceed the battery duration, The start-up property can be improved by shortening the rise time.

  In the above embodiment, when the oil temperature is equal to or higher than the predetermined reference temperature, the target rotation speed of the oil pump is fixed to a preset reference rotation speed Np1, but a control map as shown in FIG. 5 is used. Thus, the target rotation speed may be obtained. Further, the target rotational speed of the oil pump 11 may be obtained by sequential calculation without being limited to the example using the control map as shown in FIGS.

  Further, as the friction engagement element according to the present invention, the present invention is applied to the clutch that connects the engine and the motor in the hybrid vehicle in the above-described embodiment, but other friction engagement elements such as the second clutch 8 described above. It is also possible to apply the present invention to this.

2 ... Motor generator (motor)
3 ... battery 4 ... first clutch (friction engagement element)
11 ... Oil pump (pump)
20 ... Vehicle controller (target rotational speed setting means)

Claims (6)

A friction fastening element that is interposed in the power transmission system of the vehicle and switches between disconnection and connection of power transmission;
A motor that operates with electric power supplied from a battery;
A pump that is driven by the motor and supplies hydraulic fluid to the frictional engagement element;
Air content acquisition means for detecting or estimating the air content of the hydraulic fluid;
Target rotational speed setting means for setting a target rotational speed of the pump based on the air content rate when at least the temperature of the hydraulic fluid is lower than a predetermined reference temperature;
A vehicle control apparatus comprising:   2. The vehicle control device according to claim 1, wherein the target rotational speed setting means reduces the target rotational speed when the air content rate is high. The air content acquisition means detects or estimates the air content when the vehicle is stopped;
3. The vehicle control according to claim 1, wherein the target rotation speed setting means sets the target rotation speed based on the air content rate when the vehicle is stopped when the vehicle is started next time. apparatus. The target rotational speed setting means calculates the target rotational speed based on the battery duration and the hydraulic pressure rise time,
The battery duration corresponds to a time during which the battery can operate with respect to the rotation speed of the pump, and is set according to the state of the battery,
The hydraulic pressure rise time corresponds to the time required until the hydraulic pressure of the hydraulic fluid rises to a predetermined hydraulic pressure required for the operation of the frictional engagement element with respect to the rotational speed of the pump. The vehicle control device according to claim 1, wherein the vehicle control device is set based on a content rate.   5. The vehicle control device according to claim 4, wherein the target rotational speed setting unit calculates the target rotational speed so that the hydraulic pressure rising time is shorter than the battery duration. The vehicle is a hybrid vehicle that uses an engine and the motor interposed between the engine and drive wheels as a vehicle drive source,
The vehicle control device according to claim 1, wherein the frictional engagement element is a normally open clutch interposed between the engine and the motor.

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