JP2003130199A - Hybrid vehicle equipped with step variable speed gear - Google Patents

Abstract

PROBLEM TO BE SOLVED: To preferentially enable power generation by changing a gear-change step of a variable speed gear to the low side of without giving feeling of incongruity to a driver, when the power generation by a dynamo-electric machinery using a part of engine power becomes preferential, in a hybrid vehicle with a step variable speed gear. SOLUTION: This hybrid vehicle is equipped with a normal gear change map and a gear-change map being used preferentially for power generation that a gear-change line is set up on a side of speed higher than that of a usual gear-change map and the gear-change step is selected on the side of same or low, under the running condition of the above usual gear-change, and the gear- change control is done by the gear-change map being used preferentially for power generation, when the power generation by the rotational dynamo- machinery becomes preferential.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a hybrid vehicle equipped with a stepped automatic transmission.

[0002]

2. Description of the Related Art As shown in Japanese Patent Laid-Open No. 2000-110603,
2. Description of the Related Art Some hybrid vehicles that drive a vehicle by an engine and an electric motor include a stepped automatic transmission as a transmission.

[0003]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention In the hybrid vehicle having the above structure, if the electric motor connected to the engine functions as a generator, the engine output can be used to generate electric power.

By the way, when power is generated by using a part of the engine output, the surplus torque of the engine (= maximum engine torque-
It is necessary to increase the current engine torque), and in order to increase the surplus torque of the engine, it is necessary to change the gear position of the transmission to the gear position on the low side (high gear ratio side) to reduce the engine torque.

However, due to the power generation demand of the vehicle,
When the gear shift is performed irrespective of the driver's accelerator operation and vehicle speed, the engine rotation may suddenly change or a gear shift shock may occur, which may give the driver a feeling of discomfort.

The present invention has been made in view of the above technical problems, and when giving priority to the power generation by the rotating electric machine in the hybrid vehicle having the above-described structure, the shift to the low side is performed without giving a discomfort to the driver. The purpose is to prioritize power generation.

[0007]

A first aspect of the present invention relates to an engine, a stepped transmission mechanically connected to the engine, and a rotary electric machine that regenerates a part of the output of the engine to generate electric power. And a normal speed shift map, a power generation priority shift map in which a shift line is set to a higher speed side than the normal speed shift map, and a shift map of the transmission, when priority is given to power generation by the rotary electric machine, The power generation priority shift map is used, and in other cases, the shift map is switched so that the normal shift map is used, and the shift stage of the transmission is changed with reference to the shift map. And a hybrid vehicle.

According to a second aspect of the invention, when the shift map switching means in the first aspect switches the map used as the shift map of the transmission from the normal shift map to the power generation priority shift map, a shift is performed before and after the shift. It is characterized in that the shift map is switched only when the shift speed selected with reference to the map is the same.

In a third aspect of the present invention, when the shift map switching means in the first or second aspect switches the map used as the shift map of the transmission from the power generation priority shift map to the normal shift map. It is characterized in that the shift map is switched.

According to a fourth aspect of the present invention, in the first to third aspects, when a battery is connected to the rotating electric machine and power generation by the rotating electric machine is prioritized, the remaining capacity of the battery decreases to a predetermined low capacity. It is characterized by being.

[0011]

Therefore, in the hybrid vehicle according to the present invention, the rotary electric machine regenerates a part of the engine output to generate electric power. When the rotary electric machine gives priority to the electric power generation, the speed change control of the transmission is performed. The shift map used is switched from the normal shift map to the power generation priority shift map.

In order to give priority to the power generation by the rotating electric machine, it is necessary to increase the surplus torque (= maximum engine torque-current engine torque) of the engine. However, the shift line of the power generation priority shift map is higher than that of the normal shift map. Since the shift line is set to the high speed side, the same or low side (higher gear ratio side) shift stage as in the normal shift map is selected under the same driving condition, whereby the engine torque is changed. Can be lowered to increase the excess torque of the engine.

At this time, if the shift map is switched to the power generation priority shift map when the shift speeds before and after the shift are the same, the shift is performed at a timing not intended by the driver, and a sudden increase in engine rotation or a shift is performed. It is possible to prevent the driver from feeling uncomfortable due to the shock (second invention).

Furthermore, when the shift map is switched from the power generation priority shift map to the normal shift map immediately, the power generation priority state is maintained more than necessary, so that the engine is operated more than necessary. It is possible to prevent an adverse effect that the fuel economy is deteriorated by being driven on the high rotation side (third invention). In this case, the gear shift may be performed at the same time as the switching, but in that case, the gear shift is to the gear stage on the high side (small gear ratio side), and therefore the shift shock is small and the driver does not feel uncomfortable.

Further, the case where the electric power generation by the rotating electric machine is prioritized is a case where the remaining capacity (state of charge) of the battery mounted on the hybrid vehicle is lowered. In such a case, the shift map is switched. By doing so, it is possible to prevent the remaining capacity of the battery from decreasing too much, and to prevent insufficient supply of electric power to the motor and the like due to the decrease in the remaining capacity (fourth invention).

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows a schematic structure of a hybrid vehicle according to the present invention. A first rotating electric machine 2 is mechanically connected to the engine 1. Further, the engine 1 and the first rotating electric machine 2 include a transmission 4, a propeller shaft 5, a rear wheel differential device 6, and a rear wheel. It is connected to a rear wheel 8 via a drive shaft 7.

The engine 1 is provided with an electronically controlled throttle valve in addition to a fuel injection device and an ignition device. By controlling the opening of this throttle valve and adjusting the intake air amount of the engine 1, the engine 1 can be controlled. The torque can be controlled.

The first rotating electric machine 2 is an AC motor and is used when starting (cranking) the engine 1, assisting the engine output during acceleration or traveling uphill, or regenerating braking energy during deceleration. Used. When the remaining battery level is low, the surplus torque of the engine 1 is used to generate power to charge the battery 16.

A second rotary electric machine 10 is provided mechanically independent of the engine 1, the first rotary electric machine 2, etc., and the second rotary electric machine 10 is provided for the front wheel differential device 1.
1. The front wheel 13 is connected to the front wheel 13 via the front wheel drive shaft 12. The second rotary electric machine 10 is also an AC motor like the first rotary electric machine 2, is driven when four-wheel drive is required, and regenerates braking energy during deceleration.

The first rotating electric machine 2 and the second rotating electric machine 10 are connected to the battery 1 via inverters 15a and 15b, respectively.
6 is connected to the battery 1 to supply the electric power required for power running.
6, the battery 16 is charged with the electric power regenerated during the regenerative operation. Also, the battery 1
A sensor 17 for detecting the voltage across the terminals is attached to the battery 6, and the remaining capacity (state of charge) of the battery 16 can be obtained from the detected voltage between the terminals.

The transmission 4 is a stepped automatic transmission having a lock-up mechanism composed of a planetary gear mechanism, a clutch, a hydraulic circuit, etc., and shifts are performed using a shift map described later. Here, the transmission 4 is a stepped transmission having five gear stages in which the gear ratio from the first gear to the fifth gear changes discontinuously.

Control of the engine 1, the first rotating electric machine 2, the second rotating electric machine 10, etc. is performed by a CPU, a ROM, a RAM,
This is performed in the control device 20 including an input / output interface, etc., and during normal traveling, the control device 20 distributes the required driving force obtained from the accelerator operation amount, the vehicle speed, etc. to the front wheel side and the rear wheel side. , The engine 1, the first rotating electric machine 2, and the second rotating electric machine 10 are used to control the driving force.

Further, the control device 20 converts the required driving force distributed to the rear wheel side into an accelerator operation amount by referring to a predetermined map, and based on this converted accelerator operation amount and the vehicle speed, FIG.
The target gear position is set with reference to the shift map as shown in (1), and the shift control of the transmission 4 is performed according to the set gear position.

The control device 20 causes the first rotary electric machine 2 to function as a generator when the remaining capacity of the battery 16 is small, and uses the surplus torque of the engine 1 to generate electric power. When it is desired to give priority to the engine 1, it is necessary to increase the surplus torque of the engine 1. In order to increase the surplus torque, the gear position of the transmission 4 is changed to the low side (high gear ratio side) to rotate the engine 1 It is necessary to increase the speed and reduce the torque.

For example, in FIG. 3, point X is a case where the transmission 4 is traveling with the gear position of the transmission 4 as the fourth speed gear, and the surplus torque of the engine 1 in this case is the difference between the maximum engine torque and the actual engine torque. Is T1. When the gear position of the transmission 4 is changed to the third gear from this state, the operating point shifts to a point Y on the same output line as the point X, and the engine torque decreases, so that the surplus engine torque changes from T1 to T2.
Increase to.

However, if the shift speed is immediately changed to give priority to the power generation, the shift is performed regardless of the accelerator operation by the driver or the vehicle speed.
It may cause the driver to feel uncomfortable.

Therefore, in the vehicle according to the present invention, as shown in FIG. 4, each shift line is set to a higher speed side than the normal shift map shown in FIG. 2, and the low shift speed is used. Separately prepare a power generation priority shift map that expands the operating region to the high speed side, and when giving priority to power generation, the timing that does not make the driver feel uncomfortable, specifically, the shift stage before and after switching is the same The shift map is switched to the power generation priority shift map at a timing at which the shift is not performed, and thereafter, shift control is performed using this shift map until there is no need to give priority to power generation. When the power generation priority shift map is used as the shift map, the low gear is used more frequently, and the engine surplus torque can be increased.

FIG. 5 is a flow chart showing the contents of this shift map switching process, which is repeatedly executed by the controller 20 at predetermined time intervals.

According to this, first, it is determined in step S1 whether the map currently used is for normal use or for power generation priority. If it is determined that the normal speed shift map is used, step S2 and the following steps are performed. If it is determined that the shift map for power generation priority is used, the process proceeds to step S6 and subsequent steps.

In step S2, it is determined whether the state of charge SOC of the battery 16 has fallen below the threshold value SOCTH1.
To increase C, the process proceeds to step S3. If not, the process ends as it is. The threshold value SOCTH1 is set to a predetermined low remaining capacity.

In step S3, the power generation priority shift map is referred to based on the value obtained by converting the required driving force distributed to the rear wheels into the accelerator operation amount and the current vehicle speed, and the shift control is performed based on the power generation priority shift map. The shift stage Pgen which will be selected if performed is calculated. Since the shift line of the power generation priority shift map is set to a higher speed side than the shift line of the normal shift map, the shift speed Pgen is the same as or higher than the shift speed obtained by referring to the normal shift map. Also the low gear is selected.

In step S4, it is determined whether or not the shift speed set with reference to the current normal shift map is the same as the shift speed Pgen calculated in step S3. If it is determined that they are the same, the process proceeds to step S5, and the shift map used for shift control is switched from the normal shift map to the power generation priority shift map. On the other hand, if it is determined that they do not match, the process is terminated as it is and the shift map is not switched. The reason why the shift map is not switched when it is determined that they do not match is that there is no relation between the driver's accelerator operation (acceleration / deceleration intention) and the increase / decrease in vehicle speed if the shift map is switched if they do not match. This is because the gear shift is performed without any change, and the driver feels uncomfortable due to a sudden increase in the engine rotation speed or a shock at the time of gear shift.

On the other hand, if it is determined in step S1 that the map currently in use is the power generation priority shift map, the process proceeds to step S6, in which it is determined whether the remaining capacity SOC of the battery 16 exceeds the threshold value SOCTH2. It When it is determined that the state of charge SOC exceeds the threshold value SOCTH2, the process proceeds to step S7, and the shift map used for shift control is immediately switched from the power generation priority map to the normal one. The reason why the shift map is immediately switched is to prevent the power generation priority state from continuing unnecessarily and the engine from being operated on the high rotation side more than necessary to deteriorate fuel efficiency. Even if it is done, it is a shift to the high side (high speed side),
This is because there is little discomfort given to the driver.

The threshold value SOCTH2 is set to a predetermined low remaining capacity, the same value as SOCTH1, or SOCTH to prevent frequent switching of the control map.
It is set to a value greater than 1.

If it is determined in step S6 that the remaining capacity SOC has not yet reached the threshold value SOCTH2, the power generation priority map is continuously used for the shift control, and the power generation priority state is maintained so that the power generation is continued. The process ends.

Next, the operation of performing the above control will be described.

As described above, in the hybrid vehicle according to the present invention, when the state of charge SOC of the battery 16 decreases, the shift used in the shift control of the transmission 4 is prioritized to generate power by the first rotating electric machine 2. The map is switched from the normal speed shift map (FIG. 2) to the power generation priority shift map (FIG. 4).

In the power generation priority shift map, the shift line is set to a high speed side as compared with the normal shift map, and it is easy to select the low shift stage under the same operating condition. Engine 1 if a tier is selected
It is possible to increase the surplus torque of 1, and prioritize the power generation by the first rotating electric machine 2. For example, even when the accelerator pedal is similarly depressed to perform acceleration, the shift-up timing is delayed when the power generation priority shift map is used as compared to when the normal shift map is used, and the engine 1 rotation speed increases. The state where the speed is high (the state where the surplus engine torque is large and the power generation is prioritized) can be continued for a longer time.

Further, the shift from the normal shift map to the power generation prioritized shift map is performed when the shift speeds before and after the shift are the same, so that the shift is performed at a timing not intended by the driver, and a sudden increase in engine rotation or shift is performed. The driver will not feel any discomfort due to the shock.

For example, (A) and (B) of FIG. 6 respectively show the normal speed shift map and the power generation priority speed shift map, respectively.
When the vehicle is at point Z in (A) (the shift speed is the second speed at this time), the shift speed obtained by referring to the power generation priority shift map is also the same second speed gear, and thus the shift map switching is permitted. To be done. On the other hand, similarly, even when the normal shift map is selected, when the vehicle is at point W in FIG. 6A (in that case, the shift stage is the fourth speed), the power generation priority shift is performed. The gear obtained by referring to the map is the third gear,
Since the shift speed is lower than the shift speed obtained by referring to the normal shift map, shifting of the shift map is not permitted in order to suppress shifting when shifting the shift map.

As described above, the shift map is switched at the timing when the shift operation is not performed before and after the shift, that is, the shift stage obtained by referring to the shift map for power generation priority based on the current operating condition is the current shift stage (normally). It is possible to prevent the driver from feeling uncomfortable because the gear shift is performed at a timing that is not intended by the driver because the gear shift is performed at a timing that coincides with the shift speed set by referring to the gear shift map).

On the other hand, when the battery 16 is sufficiently charged and the shift map is switched from the shift map for power generation priority to the shift map for normal power generation, the shift is immediately performed, so that the state of giving priority to power generation continues more than necessary. It is possible to prevent the fuel economy from being deteriorated due to the engine being driven at a higher rotation speed than is necessary. In this case, the shift may be performed simultaneously with the map switching, but the shift in this case is always the shift to the high side (small shift ratio side) and does not give the driver a feeling of strangeness.

In the above embodiment, the power generation is prioritized when the remaining capacity of the battery 16 is decreasing, but at other times, it is consumed by the on-vehicle electrical equipment (motor, fan, etc.). The shift map switching control may be performed when the power increases.

In addition to three or more maps to be switched, for example, in addition to the normal and power generation priority maps, a power generation top priority gear shift map in which the shift line is shifted to a high speed side and power generation is prioritized is prepared. When it is necessary to rapidly increase the amount of power generation, control similar to the above-described switching control may be performed to switch to this power generation top priority shift map.

In this embodiment, the rotary electric machine 2
Is arranged between the engine 1 and the transmission 4, but the invention is not limited to this.
May be attached to any place of the engine 1 and connected by a belt or a chain so as to rotate in synchronization with the engine 1 at a predetermined gear ratio.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a hybrid vehicle to which the present invention is applied.

FIG. 2 is a shift map for normal use.

FIG. 3 is a diagram for explaining a surplus torque of the engine.

FIG. 4 is a shift map for power generation priority.

FIG. 5 is a flowchart showing the content of shift map switching processing.

FIG. 6 is a diagram for explaining map switching control according to the present invention.

[Explanation of symbols]

1 engine 2 First rotating electrical machine 4 transmission 10 Second rotating electric machine 16 battery 20 Control device

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 3J552 MA01 MA02 NA01 NB01 NB08                       NB10 PA51 PA59 SB02 SB25                       UA10 VA32W VB10W VC01W                 5H115 PA01 PC06 PG04 PI16 PI24                       PI29 PO02 PO06 PO09 PO17                       PU08 PU24 PU25 PU28 PU29                       PV10 QE20 QI04 QN03 RB08                       RB15 RB21 SE04 SE05 SE06                       SE08 TB03 TI02 TI05 TO21

Claims (4)

[Claims] 1. An engine, a stepped transmission mechanically connected to the engine, a rotating electric machine that regenerates a part of the output of the engine to generate electric power, a normal-use shift map, and the normal-use shift map. The power generation priority shift map in which the shift line is set to a higher speed side than the shift map, and the power generation priority shift map is used as the shift map of the transmission when power generation by the rotating electric machine is prioritized, and other than that. In the case of, the shift map switching means for switching the shift map so that the normal shift map is used, and means for changing the shift stage of the transmission with reference to the shift map are provided. Hybrid vehicle. 2. When the map used as the shift map of the transmission is switched from the normal shift map to the power generation priority shift map, the shift map switching means is selected by referring to the shift map before and after the shift. The hybrid vehicle according to claim 1, wherein the shift map is switched only when the shift speed is the same. 3. The shift map switching means switches the shift map immediately when the map used as the shift map of the transmission is switched from the power generation priority shift map to the normal shift map. The hybrid vehicle according to claim 1. 4. A battery is connected to the rotating electric machine, and the case of giving priority to power generation by the rotating electric machine is a case where the remaining capacity of the battery is reduced to a predetermined low capacity. The hybrid vehicle according to any one of claims 1 to 3.