JP2015113068A - Hybrid vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hybrid vehicle capable of preventing shortage or excess of a SOC (State of Charge) when an accelerator is stepped on, by changing regenerative braking force from standard regenerative braking force.SOLUTION: In a case where regenerative braking force is changed from standard regenerative braking force by a regenerative level selector 230, an ECU 320 changes a start threshold of an engine 120 from a start threshold of the engine 120 when the standard regenerative braking force is set.

Description

  The present invention relates to a hybrid vehicle, and more particularly to a hybrid vehicle having a function of variably setting a regenerative braking force.

  In Patent Document 1 (Japanese Patent Laid-Open No. 08-079907), the regenerative braking force when the accelerator is off can be changed from the standard (default) regenerative braking force by the driver's operation, and the regenerative braking is performed by turning on the accelerator. An end vehicle is disclosed.

Japanese Patent Application Laid-Open No. 08-079907

  However, in the vehicle described in Patent Document 1, when the regenerative braking force is changed from the standard regenerative braking force, the regenerative amount also changes from the standard regenerative amount. When the regenerative amount changes from the standard regenerative amount, the SOC (State of Charge) of the storage battery also changes from the standard SOC. For example, if the regenerative braking force is set smaller than the standard regenerative braking force, the SOC becomes smaller than the standard SOC. Conversely, if the regenerative braking force is set larger than the standard regenerative braking force, the SOC becomes larger than the standard SOC.

  As described above, since the SOC is changed by changing the regenerative braking force, there is a problem that the SOC becomes insufficient or the SOC becomes excessive when the accelerator is on.

  Therefore, an object of the present invention is to provide a hybrid vehicle that can prevent the SOC from becoming insufficient or excessive when the accelerator is on by changing the regenerative braking force from the standard regenerative braking force. is there.

  In order to solve the above problems, a hybrid vehicle of the present invention includes an internal combustion engine, an electric motor capable of outputting a regenerative braking force, a setting unit for changing the regenerative braking force from a standard regenerative braking force, and a regenerative control by the setting unit. When the power is changed from the standard regenerative braking force, the control unit changes the start threshold value of the internal combustion engine from the start threshold value of the internal combustion engine when the standard regenerative braking force is set.

  By changing the regenerative braking force from the standard regenerative braking force, it is possible to prevent the SOC from being insufficient or excessive when the accelerator is on.

It is a control block diagram of the hybrid vehicle which concerns on embodiment of this invention. It is a figure showing the relationship with the regeneration level (ReL) selected by the regeneration level selector, the regenerative braking force (ReF), and the engine starting threshold value (TH). It is a flowchart showing the control procedure of embodiment of this invention. (A) is a figure showing the state of an accelerator. (B) is a figure showing vehicle speed. (C) is a figure showing vehicle request power. (D) is a figure showing SOC of a battery for driving | running | working.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same parts are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

A control block diagram of a hybrid vehicle according to an embodiment of the present invention will be described with reference to FIG. The present invention is not limited to the hybrid vehicle shown in FIG. It may be a hybrid vehicle having another aspect equipped with a secondary battery. In addition, a storage mechanism such as a capacitor may be used instead of the secondary battery. Moreover, in the case of a secondary battery, it is a nickel metal hydride battery, a lithium ion battery, etc., The kind is not specifically limited.

The hybrid vehicle includes an internal combustion engine (hereinafter simply referred to as an engine) 120 such as a gasoline engine or a diesel engine as a drive source, and a first MG (Motor Generator).
141 and the second MG 142.

  In addition to this, in the hybrid vehicle, the power generated by the engine 120 and the second MG 142 is transmitted to the driving wheel 160, the drive of the driving wheel 160 is transmitted to the engine 120 and the second MG 142, and the generation of the engine 120 Power split mechanism (for example, planetary gear mechanism) 200 that distributes the power to be driven to two paths of drive wheel 160 and first MG 141, travel battery 220 that charges power for driving second MG 142, and travel battery 220 And an inverter 240 that performs current control while converting the DC of the second MG 142 and the AC of the first MG 141.

  In the present embodiment, boost converter 242 is provided between battery for traveling 220 and inverter 240. This is because the rated voltage of the traveling battery 220 is lower than the rated voltage of the second MG 142 or the first MG 141, so that when the power is supplied from the traveling battery 220 to the second MG 142 or the first MG 141, the boost converter 242 boosts the power. .

  The hybrid vehicle further includes a brake disc 402 provided on a drive shaft 400 connected to the drive wheel 160, a brake mechanism 404, and a hydraulic controller 406. The brake mechanism 404 receives the brake hydraulic pressure from the hydraulic controller 406, and sandwiches the brake disc 402 according to the received brake hydraulic pressure to generate a friction braking force, thereby decelerating the vehicle. The hydraulic controller 406 receives the brake control signal from the ECU 310, calculates the brake hydraulic pressure for generating the friction braking force (hydraulic brake) indicated by the brake control signal, and outputs the calculated brake hydraulic pressure to the brake mechanism 404. .

  The hybrid vehicle controls the operating state of the engine 120, and controls the first MG 141, the second MG 142, the traveling battery 220, the inverter 240, etc. according to the state of the hybrid vehicle, and the hybrid vehicle is most efficient. An ECU 320 that controls the entire hybrid system is provided so that it can be operated.

  Power split mechanism 200 uses a planetary gear mechanism (planetary gear) to distribute the power of engine 120 to both drive wheel 160 and first MG 141. By controlling the rotation speed of first MG 141, power split device 200 also functions as a continuously variable transmission. The rotational force of engine 120 is input to planetary carrier (C), which is transmitted to first MG 141 by sun gear (S), and to the motor and output shaft (drive wheel 160 side) by ring gear (R). When the rotating engine 120 is stopped, since the engine 120 is rotating, the kinetic energy of this rotation is converted into electric energy by the first MG 141 to reduce the rotational speed of the engine 120.

  In a hybrid vehicle equipped with a hybrid system as shown in FIG. 1, the hybrid vehicle travels only by the power running control of the second MG 142 when the engine 120 is inefficient at the time of starting or traveling at a low speed.

  When the vehicle required power reaches a threshold value (engine start threshold value) for starting engine 120, engine 120 is started. The vehicle required power is set based on the accelerator opening Acc and the vehicle speed V.

  During normal travel, for example, the power split mechanism 200 divides the power of the engine 120 into two paths, and on the one hand, the drive wheels 160 are directly driven, and on the other hand, the first MG 141 is driven to generate power. At this time, the second MG 142 is subjected to power running control with the generated electric power to assist driving of the driving wheels 160.

  Further, at the time of high speed traveling, power from traveling battery 220 is further supplied to second MG 142 to increase the output of second MG 142 and drive force is added to drive wheels 160. On the other hand, during deceleration, the second MG 142 driven by the drive wheel 160 is regeneratively controlled to function as a generator to perform regenerative power generation, and the recovered power is stored in the traveling battery 220.

  When the amount of charge of traveling battery 220 is reduced and charging is particularly necessary, the output of engine 120 is increased to increase the amount of power generated by first MG 141 to increase the amount of charge for traveling battery 220. Of course, control is performed to increase the drive amount of the engine 120 as necessary even during low-speed traveling. For example, it is necessary to charge the traveling battery 220 as described above, to drive an auxiliary machine such as an air conditioner, or to raise the temperature of the cooling water of the engine 120 to a predetermined temperature.

  The speed sensor 128 detects the speed (vehicle speed) V of the vehicle. The brake sensor 126 detects depression of the brake pedal. The accelerator sensor 125 detects the accelerator opening Acc.

  The regeneration level selector 230 selects the regeneration level according to the paddle operation of the user. In the embodiment of the present invention, the regeneration level is, for example, five stages of B0 to B5, and the regenerative braking force by the second MG 142 is smaller as the regeneration level is smaller.

  FIG. 2 is a diagram showing the relationship between the regeneration level (ReL), the regenerative braking force (ReF), and the engine start threshold (TH) selected by the regeneration level selector 230.

  When the regeneration level B0, B1, B2, B3, B4, B5 is selected by the regeneration level selector 230, the regenerative brake is operated with the regenerative braking force RB0, RB1, RB2, RB3, RB4, RB5, respectively, when the accelerator is off. . Here, RB0 <RB1 <RB2 <RB3 <RB4 <RB5.

  Further, when regeneration levels B0, B1, B2, B3, B4, and B5 are selected by regeneration level selector 230, engine start threshold values a0, a1, a2, a3, a4, and a5 are obtained, respectively. Here, a0 <a1 <a2 <a3 <a4 <a5.

  The regenerative level B2 is a standard (default) level, the regenerative braking force RB2 is a standard (default) regenerative braking force, and the engine start threshold a2 is a standard (default) engine start threshold.

  When the D range (forward) is selected by the select bar 191 and the regeneration level is not selected by the regeneration level selector 230, the regeneration level is maintained at the standard (default) level B2.

  ECU 320 operates the hydraulic brake together with the regenerative brake so that a braking force corresponding to the amount of depression of the brake pedal is generated while the driver is depressing the brake pedal. Alternatively, ECU 320 sets the regenerative braking force immediately after the start of depressing the brake pedal to a magnitude corresponding to the regenerative level selected by regenerative level selector 230, and then generates a braking force corresponding to the amount of depression of the brake pedal. The hydraulic brake may be operated together with the regenerative brake.

FIG. 3 is a flowchart showing a control procedure according to the embodiment of the present invention.
In step S101, when a power switch (not shown) is operated, the vehicle system is activated (becomes a Ready-ON state).

  In step S102, when the driver depresses the accelerator pedal (accelerator on), the process proceeds to step S103, and when the driver does not depress the accelerator pedal (accelerator off), the process proceeds to step S107. move on.

  In step S103, when engine 120 is in a stopped state, the process proceeds to step 105, and when engine 120 is in an operating state, the process proceeds to step S104.

  In step S104, ECU 320 normally controls engine 120, second MG 142, and first MG 141 in accordance with the vehicle required power.

  In step S105, when the vehicle required power is equal to or higher than TH (ReL), that is, the engine start threshold TH at the selected regeneration level ReL, the process proceeds to step S106.

In step S106, ECU 320 starts engine 120.
If the driver depresses the brake pedal in step S107 (brake on), the process proceeds to step S108. If the driver does not depress the brake pedal (ie, brake off), the process proceeds to step S109. Proceed to

  In step S108, ECU 320 performs regenerative control of second MG 142 to operate the regenerative brake and the hydraulic brake.

  In step S109, ECU 320 performs regenerative control of second MG 142 at the selected regenerative level to operate the regenerative brake.

  Next, a comparison between a case where the vehicle is decelerated and coasted when the regeneration level is “0” (conventional) and a case where the vehicle speed is maintained (embodiment of the present invention) will be described.

  4 (a) shows the state of the accelerator, FIG. 4 (b) shows the vehicle speed, FIG. 4 (c) shows the vehicle required power, and FIG. 4 (d) shows the SOC of the traveling battery 220. Represents.

  From time t0 to time t1, the vehicle is in a coasting state where the accelerator is off, and the vehicle speed decreases. ECU 320 controls regeneration of second MG 142 at the regeneration level selected by regeneration level selector 230. In the coasting state, the SOC of the battery 220 is reduced by using an auxiliary machine such as an air conditioner, but the reduction of the SOC can be compensated for by regenerative power generation. As the selected regeneration level increases, the regenerative braking force increases and the amount of regenerative power generated by the second MG 142 increases. Therefore, in the coasting state, the smaller the selected regeneration level, the larger the amount that the SOC decreases. FIG. 4D shows that the slope of the straight line representing the decrease in SOC is the highest at the regeneration level B0, and the slope of the straight line becomes smaller in the order of B1, B2, B3, B4, and B5.

  At time t1, the accelerator is turned on, and the accelerator opening gradually increases. Along with this, the vehicle speed and the required vehicle power increase.

  Since the vehicle required power reaches the engine start threshold value a0 at the regeneration level B0 at the time point t2, the engine 120 is started when the regeneration level is set to B0. As a result, the SOC of battery for traveling 220 increases.

  At time t3, the vehicle required power reaches the engine start threshold value a1 at the regeneration level B1, so that the engine 120 is started when the regeneration level is set to B1. As a result, the SOC of battery for traveling 220 increases.

  At time t4, the vehicle required power reaches the engine start threshold value a2 at the regeneration level B2, so that the engine 120 is started when the regeneration level is set to B2. As a result, the SOC of battery for traveling 220 increases.

  At time t5, the vehicle required power reaches the engine start threshold value a3 at the regeneration level B3, so the engine 120 is started when the regeneration level is set to B3. As a result, the SOC of battery for traveling 220 increases.

  At time t6, the vehicle required power reaches the engine start threshold value a4 at the regeneration level B4. Therefore, when the regeneration level is set to B4, the engine 120 is started. As a result, the SOC of battery for traveling 220 increases.

  At time t7, the vehicle required power reaches the engine start threshold value a5 at the regeneration level B5, so the engine 120 is started when the regeneration level is set to B5. As a result, the SOC of battery for traveling 220 increases.

  In FIG. 4, the SOC at regeneration level B0 at time t2, the SOC at regeneration level B1 at time t3, the SOC at regeneration level B2 at time t4, the SOC at regeneration level B3 at time t5, and the regeneration level at time t6. Although the SOC at B4 and the SOC at the regeneration level B5 at time t7 are illustrated as being the same level, they are not necessarily the same level.

  As described above, according to the present embodiment, the lower the regeneration level, the smaller the SOC in the coasting state. Therefore, by setting the engine start threshold value small, the time from the accelerator on to the engine start being shortened. In addition, the SOC can be quickly recovered.

  In the present embodiment, the vehicle start power value required for starting the engine has been described as the engine start threshold. However, the present invention is not limited to this. The engine start threshold value may be a SOC value required for engine start or a vehicle speed value required for engine start.

  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.

  120 engine, 125 accelerator sensor, 126 brake sensor, 128 speed sensor, 141 1st MG, 142 2nd MG, 160 driving wheel, 180 reducer, 191 select bar, 200 power split mechanism, 220 battery for traveling, 230 regeneration level selector, 240 Inverter, 242 Boost converter, 320 ECU, 400 Drive shaft, 402 Brake disc, 404 Brake mechanism, 406 Hydraulic controller.

Claims (1)

An internal combustion engine;
An electric motor capable of outputting regenerative braking force;
A setting unit for changing the regenerative braking force from a standard regenerative braking force;
When the regenerative braking force is changed from the standard regenerative braking force by the setting unit, the start threshold value of the internal combustion engine when the standard regenerative braking force is set is used as the start threshold value of the internal combustion engine. A hybrid vehicle comprising a control unit that changes from the above.

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