JP2017185839A - Hybrid vehicle and control method of hybrid vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hybrid vehicle and a control method of a hybrid vehicle capable of preventing seizure of a clutch even if the clutch is engaged when a temperature of a working fluid is high.SOLUTION: In order to make a multiple disc clutch 14 whose power source is a working fluid O that is arranged between an engine 10 and a motor generator 21 come to an engagement state based on an operational state of engine 10, a tolerable rotational speed α is preset based on temperature T of the working fluid O, engagement of the multiple disc clutch 14 is started after a rotation speed difference ΔNe of an input/output shaft of the multiple disc clutch 14 comes to be the set tolerable rotational speed α or less.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a hybrid vehicle and a hybrid vehicle control method.

  In recent years, a hybrid vehicle (hereinafter referred to as “HEV”) including a hybrid system having an engine and a motor generator that are controlled in combination according to the driving state of the vehicle has attracted attention from the viewpoint of improving fuel efficiency and environmental measures. (For example, refer to Patent Document 1).

  In this hybrid vehicle, a clutch using hydraulic oil as a power source may be disposed between the engine and the motor generator.

JP 2002-238105 A

  By the way, if this clutch is connected when the temperature of the hydraulic oil is high, the kinematic viscosity of the hydraulic oil is lowered and the hydraulic pressure is lowered, so that the connection speed of the clutch is slowed and the connection time is lengthened. If the clutch input / output shaft speed difference is large at this time, the total amount of heat generated on the frictional surface of the clutch (clutch connection time x generated heat amount associated with the input / output shaft speed difference) is excessive. There was a possibility that clutch seizure would occur due to the high temperature.

  An object of the present invention is to provide a hybrid vehicle and a hybrid vehicle control method capable of preventing the seizure of the clutch even when the clutch is connected when the temperature of the hydraulic oil is high.

  The hybrid vehicle of the present invention that achieves the above object includes an engine and a motor generator that are power sources for driving the vehicle, a clutch that uses hydraulic oil disposed between the engine and the motor generator as a power source, In a hybrid vehicle configured to include a hybrid system having a control device, the rotational speed of the input / output shaft of the clutch when the control device brings the clutch into an engaged state based on the operating state of the engine. The clutch is started when the difference becomes equal to or less than a preset allowable rotational speed, and the allowable rotational speed is set based on the temperature of the hydraulic oil.

  In addition, the hybrid vehicle control method of the present invention that achieves the above object includes a clutch that uses hydraulic oil as a power source between an engine that is a power source for driving the vehicle and a motor generator, and the clutch is connected and disconnected. In the hybrid vehicle control method for switching the state based on the operating state of the engine, when the clutch is brought into the engaged state, an allowable rotational speed is set in advance based on the temperature of the hydraulic oil, and the clutch input / output In this method, the clutch is started to be connected after the difference in shaft rotational speed becomes equal to or less than the set allowable rotational speed.

  According to the hybrid vehicle and the hybrid vehicle control method of the present invention, when the clutch is engaged (set to the engaged state) based on the operating state of the engine, the rotational speed (allowable rotational speed) for starting the clutch engagement is operated. Since it sets based on the temperature of oil, the high temperature of a clutch can be suppressed and the burning of a clutch can be prevented.

It is a block diagram of the hybrid vehicle which consists of embodiment of this invention. It is a control flowchart explaining the control method of the hybrid vehicle which consists of embodiment of this invention. It is a figure which shows an example of the control map which set the allowable rotation speed with respect to the temperature of hydraulic fluid.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a hybrid vehicle according to an embodiment of the present invention.

  This hybrid vehicle (hereinafter referred to as “HEV”) is a normal passenger car or a large vehicle such as a bus or a truck, and is a hybrid that controls the vehicle in combination with the engine 10, the motor generator 21, the transmission 30, and the driving state. System 20 is mainly provided.

  In the engine 10, the crankshaft 13 is rotationally driven by thermal energy generated by the combustion of fuel in a plurality (four in this example) of cylinders 12 formed in the engine body 11. The engine 10 is a diesel engine or a gasoline engine. One end of the crankshaft 13 is connected to one end of a rotating shaft 22 of the motor generator 21 via an engine clutch 14 that is a wet multi-plate clutch. The engine clutch 14 is a clutch that uses hydraulic oil O as a power source (switches between a disconnected state and a contact state by the hydraulic pressure of the hydraulic oil O).

  The motor generator 21 is a permanent magnet AC synchronous motor capable of generating operation. The other end of the rotating shaft 22 of the motor generator 21 is connected to the input shaft 31 of the transmission 30 through the torque converter 17 and the transmission clutch 15 (for example, a wet multi-plate clutch).

  The transmission 30 uses an AMT or an AT that automatically shifts to a target gear determined based on the HEV operating state and preset map data. The transmission 30 is not limited to an automatic transmission type such as AMT, and may be a manual type in which a driver manually changes gears.

  The rotational power changed by the transmission 30 is transmitted to the differential 34 through the propeller shaft 33 connected to the output shaft 32, and is distributed as a driving force to the pair of driving wheels 35 as rear wheels.

  The hybrid system 20 includes a motor generator 21, an inverter 23 electrically connected to the motor generator 21, a high voltage battery 24, a DC / DC converter 25, and a low voltage battery 26.

  Preferred examples of the high voltage battery 24 include a lithium ion battery and a nickel metal hydride battery. The low voltage battery 26 is a lead battery.

  The DC / DC converter 25 has a function of controlling the charge / discharge direction and the output voltage between the high voltage battery 24 and the low voltage battery 26. The low voltage battery 26 supplies power to various vehicle electrical components 27.

  Various parameters in the hybrid system 20 such as a current value, a voltage value, and an SOC are detected by a BMS (battery management system) 28.

  The hybrid system 20 including the engine 10 and the motor generator 21 includes a control device 70, and the hybrid system 20 is controlled by the control device 70. Specifically, at the time of HEV start or acceleration, the hybrid system 20 assists at least a part of the driving force by the motor generator 21 supplied with power from the high voltage battery 24, while at the time of inertia traveling or braking. Performs regenerative power generation by the motor generator 21, converts surplus kinetic energy generated in the propeller shaft 33 and the like into electric power, and charges the high-voltage battery 24. Further, the HEV can perform so-called motor independent traveling using only the motor generator 21 as a power source for traveling of the vehicle by disengaging the engine clutch 14 and engaging the transmission clutch 15.

  The hybrid vehicle of the present invention includes an engine 10 and a motor generator 21 that are power sources for driving a vehicle, and a wet multi-plate clutch (engine) that uses hydraulic oil O disposed between the engine 10 and the motor generator 21 as a power source. The vehicle is configured to include a hybrid system 20 having a clutch 14 and a control device 70.

  Here, when the engine clutch 14 is connected (set to the engaged state), the engine clutch 14 is not operated until the rotational speed difference ΔNe between the input and output shafts of the engine clutch 14 becomes equal to or smaller than an allowable rotational speed α set in advance through experiments or the like. The connection has started.

  However, when the engine clutch 14 is connected when the temperature of the hydraulic oil O is high, the kinematic viscosity of the hydraulic oil O decreases and the operating oil pressure decreases, so the connection speed of the engine clutch 14 becomes slow (connection of the engine clutch 14). Time will be longer). If the input / output shaft rotational speed difference ΔNe is large at this time, the total amount of heat generated on the friction surface of the engine clutch 14 (engine clutch 14 connection time × input / output shaft rotational speed difference ΔNe generated heat amount) is excessive. As a result, the engine clutch 14 becomes hot and the engine clutch 14 may be seized.

  Therefore, in the present invention, when the control device 70 brings the engine clutch 14 into the engaged state based on the operating state of the engine 10, the rotational speed difference ΔNe between the input and output shafts of the engine clutch 14 is less than the allowable rotational speed α. Then, the connection of the engine clutch 14 is started, and the allowable rotational speed α is set based on the temperature T of the hydraulic oil O.

  That is, when the engine clutch 14 is connected based on the operating state of the engine 10 (the contact state is set), a change in connection time (change in connection speed) of the engine clutch 14 due to a temperature change of the hydraulic oil O is taken into consideration. Then, the allowable rotational speed α at which the connection of the engine clutch 14 is started is set. In setting the allowable rotational speed α, for example, a control map in which the allowable rotational speed α is set with respect to the temperature T of the hydraulic oil O as shown in FIG. 3 is created in advance and stored in the control device 70. The control map stored in the control device 70 is used.

  Here, the temperature T of the hydraulic oil O is detected by a temperature sensor (not shown) disposed in the engine clutch 14. Further, the rotational speed difference ΔNe between the input and output shafts of the engine clutch 14 is the rotational speed Nb of the output shaft (rotary shaft on the motor generator 21) 22b based on the rotational speed Na of the input shaft (rotary shaft on the engine 10 side) 22a. Calculated by subtraction. The rotational speed Na of the input shaft 22a is calculated as the same value as the rotational speed Nc of the engine 10 detected by an engine rotational speed detection sensor (not shown). The rotational speed Nb of the output shaft 22b is calculated as the same value as the rotational speed Nm of the motor generator 21 detected by a rotational speed detection sensor (not shown) of the motor generator 21.

  In the hybrid vehicle described above, control device 70 sets allowable rotational speed α to first rotational speed α1 when temperature T of hydraulic oil O is lower than preset temperature T1 that is set in advance through experiments or the like. When the temperature T of the hydraulic oil O is equal to or higher than the set temperature T1, the allowable rotational speed α is set to the second rotational speed α2 that is equal to or lower than the first rotational speed α1, and the temperature T of the hydraulic oil O becomes high. Accordingly, the second rotational speed α2 is reduced.

  This set temperature T1 is set in consideration of a temperature range in which seizure of the engine clutch 14 may occur due to a change in connection time of the engine clutch 14 (change in connection speed) caused by the temperature T of the hydraulic oil O. Temperature. That is, if the temperature T of the hydraulic oil O is lower than the set temperature T1 (normal temperature range), there is no possibility that the engine clutch 14 will be seized, while the temperature T of the hydraulic oil O is equal to or higher than the set temperature T1 (high temperature range). If there is, there is a risk that the engine clutch 14 will burn.

  The first rotation speed α1 is set to 2000 rpm, for example, and the second rotation speed α2 is set to a rotation speed value between 1000 and 2000 rpm, for example. In FIG. 3, the second rotational speed α2 is illustrated so as to decrease continuously and linearly as the temperature T of the hydraulic oil O becomes higher, but the second rotational speed α2 is intermittent (for example, It may be small (on the stairs) or may be small so that the second rotation speed α2 draws a curve.

  According to this configuration, when the temperature T of the hydraulic oil O is in the high temperature region (set temperature T1 or higher), the input / output shaft that starts the connection of the wet multi-plate clutch 14 as the temperature T of the hydraulic oil O becomes higher. Since the hydraulic oil O becomes high temperature and the connection time of the wet multi-plate clutch 14 becomes longer, the rotational speed difference ΔNe of the wet multi-plate clutch 14 is increased. Since the amount of generated heat can be reduced and an increase in the total amount of generated heat from the start of connection of the wet multi-plate clutch 14 to the completion of connection can be suppressed, the high temperature of the wet multi-plate clutch 14 can be reliably suppressed. it can.

  Next, a control method of such a hybrid vehicle (HEV) will be described below in the form of a control flowchart based on FIG. The control device 70 is connected to the engine clutch 14 through a signal line (indicated by a one-dot chain line), but other devices (for example, the transmission clutch 15) and various sensors (for example, an engine speed detection sensor) are also connected. Although not shown, they are connected.

  The control flow of FIG. 2 will be described. The control flow in FIG. 2 is a control flow that is called from the advanced control flow and starts when the engine clutch 14 is connected (set to the contact state) based on the operating state of the engine 10. When the control flow of FIG. 2 starts, in step S10, the temperature T of the hydraulic oil O is detected by a sensor for operation control of the engine clutch 14, and the rotational speed difference ΔNe of the input / output shaft of the engine clutch 14 is calculated. . Since the calculation method of the rotational speed difference ΔNe between the input and output shafts of the engine clutch 14 is the same as that described above, the description thereof is omitted here. After performing the control of step S10, the process proceeds to step S20.

  In step S20, the allowable rotational speed α is set based on the temperature T of the hydraulic oil O detected in step S10. As described above, the allowable rotational speed α is set using, for example, a control map as shown in FIG. After performing the control of step S20, the process proceeds to step S30.

  In step S30, it is determined whether or not the rotational speed difference ΔNe calculated in step S10 is equal to or smaller than the allowable rotational speed α set in step S20. When the rotational speed difference ΔNe is less than the allowable rotational speed α (NO), the determination in step S30 is performed again after a preset control time has elapsed. On the other hand, if the rotational speed difference ΔNe is equal to or larger than the allowable rotational speed α (YES), the process proceeds to step S40, and the connection of the engine clutch 14 is started in step S40. And after implementing control of Step S40, it progresses to a return and ends this control flow.

  As described above, the hybrid vehicle control method of the present invention based on the above-described hybrid vehicle is a wet type using hydraulic oil O as a power source between the engine 10 and the motor generator 21 which are power sources for driving the vehicle. In the control method of a hybrid vehicle that includes the multi-plate clutch 14 and switches the connection / disconnection state of the wet multi-plate clutch 14 based on the operating state of the engine 10, when the wet multi-plate clutch 14 is brought into the contact state, the hydraulic oil The allowable rotational speed α is set in advance based on the temperature T of O, and after the rotational speed difference ΔNe of the input / output shaft of the wet multi-plate clutch 14 becomes equal to or less than the set allowable rotational speed α, the wet multi-plate clutch 14 In this method, the connection is started.

  According to the hybrid vehicle and the hybrid vehicle control method of the present invention, the connection of the wet multi-plate clutch 14 is started when the wet multi-plate clutch 14 is connected (set to the contact state) based on the operating state of the engine 10. Since the rotational speed (allowable rotational speed) α is set based on the temperature T of the hydraulic oil O, the high temperature of the wet multi-plate clutch 14 can be suppressed, and seizure of the wet multi-plate clutch 14 can be prevented. .

10 Engine 11 Engine body 14 Engine clutch (wet multi-plate clutch)
20 Hybrid system 21 Motor generator 22a Engine clutch input shaft 22b Engine clutch output shaft 70 Controller O Hydraulic oil T Hydraulic oil temperature T1 Set temperature ΔNe Engine clutch input / output shaft rotational speed difference α Allowable rotational speed α1 First Rotational speed α2 Second rotational speed

Claims (3)

A hybrid system having an engine and a motor generator, which are power sources for vehicle travel, a clutch that uses hydraulic oil disposed between the engine and the motor generator as a power source, and a control device. In the hybrid vehicle
The control device is
When the clutch is brought into the engaged state based on the operating state of the engine, the clutch input / output shaft rotation speed difference is less than or equal to a preset allowable rotation speed, and the clutch connection is started.
A hybrid vehicle configured to set the allowable rotational speed based on a temperature of the hydraulic oil. The control device is
When the temperature of the hydraulic oil is lower than a preset temperature, the allowable rotational speed is set to the first rotational speed,
When the temperature of the hydraulic oil is equal to or higher than the set temperature, the allowable rotational speed is set to a second rotational speed that is equal to or lower than the first rotational speed, and the second rotation is performed as the temperature of the hydraulic oil becomes higher. The hybrid vehicle according to claim 1, wherein the hybrid vehicle is configured to reduce the number. In a control method for a hybrid vehicle, comprising a clutch that uses hydraulic oil as a power source between an engine that is a power source for driving the vehicle and a motor generator, and switching a connection / disconnection state of the clutch based on an operating state of the engine.
When the clutch is brought into a contact state, an allowable rotational speed is set in advance based on the temperature of the hydraulic oil, and the rotational speed difference between the input and output shafts of the clutch becomes equal to or less than the set allowable rotational speed. A method for controlling a hybrid vehicle, characterized by starting connection of a clutch.

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