JP2006029174A - Torque control device for hybrid vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a torque control device for a hybrid vehicle, for driving an engine by a motor to create an idle condition without returning to fuel cut only when it is determined that the vehicle stops soon in deceleration of the vehicle, and for returning to the fuel cut as before when it is not determined whether or not the vehicle will stop in coasting operation of the vehicle . <P>SOLUTION: The torque control device for a hybrid vehicle comprises: a fuel cut means performing fuel cut of the internal combustion engine 1 in deceleration of the vehicle; a fuel cut recovery means supplying the fuel to the internal combustion engine 1 when a fuel cut recovery condition wherein fuel supply to the internal combustion engine 1 is restarted is satisfied; a vehicle stop estimation means for estimating the stop of the vehicle; and a motor idle control means prohibiting the restart of the fuel supply to the internal combustion engine 1 and make an electric motor 2 idle the internal combustion engine 1 when it is determined that the fuel cut recovery condition is satisfied by the fuel cut recovery means and the vehicle stop estimation means estimates the stop of the vehicle. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a torque control device for a hybrid vehicle. In particular, the present invention is suitable for application to a one-motor hybrid vehicle having no motor travel mode.

A hybrid vehicle has a drive system in which an internal combustion engine and a rotating electric machine are combined, and regenerates deceleration energy in order to improve fuel efficiency during deceleration. In general, the regenerative power is reduced as the vehicle speed decreases for drivability.
An example of torque control in a one-motor hybrid vehicle (see Patent Document 1) that does not have a motor running mode is shown in FIGS.

FIG. 4 is a flowchart of torque control, and FIG. 5 is a time chart regarding the accelerator opening, the vehicle speed, the engine torque, and the motor torque.
As shown in FIG. 5, when the accelerator opening becomes 0, regeneration by motor torque is performed to improve fuel efficiency during deceleration, while fuel supply to the engine is stopped (F / C: fuel cut), and engine torque Becomes 0.
In order to ensure drivability, the regenerative power, which is the motor torque, gradually decreases as the vehicle speed decreases.

When the vehicle speed further decreases and the fuel cut return condition is satisfied (step S1), the fuel supply is resumed by the fuel cut return (F / C return) and waits in the engine idle state (step S7).
The reason why the engine fuel cut must be restored is to ensure drivability such as re-acceleration.

Next, after returning from the fuel cut in step S7, if the vehicle stop condition is satisfied (step S4), it is determined whether the idle stop stop condition is satisfied (step S5).
When the idle stop stop condition is satisfied, idling by the engine is stopped (step S6), and when the idle stop stop condition is not satisfied, the engine waits in a normal idling state by supplying fuel to the engine (step S8).
JP 10-339186 A

In the above-described prior art, even if it is known that the vehicle stops idling after stopping, the fuel cut is restored to ensure drivability such as re-acceleration, so that the fuel consumption is reduced due to the fuel supply to the engine.
The present invention has been made in view of the above-described prior art, and only when it can be determined that the vehicle stops as it is at the time of deceleration, the fuel cut is not returned, the engine can be driven by a motor to create a motor idle state, and coasting or the like is stopped. If it is not known whether or not it is an object, it is an object of the present invention to provide a hybrid vehicle torque control device capable of performing fuel cut recovery as before.

  A torque control apparatus for a hybrid vehicle according to claim 1 of the present invention that solves the above-described problems includes fuel cut means for cutting fuel to the internal combustion engine when the vehicle is decelerated, and fuel cut return for restarting fuel supply to the internal combustion engine. When the condition is satisfied, it is determined that the fuel cut return condition is satisfied by the fuel cut return means for supplying fuel to the internal combustion engine, the vehicle stop estimation means for estimating the stop of the vehicle, and the fuel cut return means, and And a motor idle control means for prohibiting resumption of fuel supply to the internal combustion engine and idling the internal combustion engine with an electric motor when the stop of the vehicle is estimated by the vehicle stop estimation means. And

  A torque control apparatus for a hybrid vehicle according to a second aspect of the present invention for solving the above-mentioned problems is characterized in that, in the first aspect, the vehicle stop estimating means is a brake switch.

  A torque control apparatus for a hybrid vehicle according to a third aspect of the present invention for solving the above-mentioned problems is characterized in that, in the first aspect, the internal combustion engine is stopped when an idle stop condition is satisfied when the vehicle is stopped.

  In the present invention, when it is estimated by the vehicle stop estimating means that the vehicle will stop as it is, even if it is determined that the fuel cut return condition is satisfied and the fuel cut return means can restart the fuel supply, the motor The idle control means prohibits the fuel supply to the internal combustion engine and idles the internal combustion engine with the electric motor. Therefore, in the short time from deceleration to stop, the fuel supply to the internal combustion engine is not resumed and the fuel cut is resumed, but the internal combustion engine is idled by driving the motor, so that the fuel consumption is better than the fuel cut restoration. Further, when the vehicle is re-accelerated during motor idling, the vehicle stop estimation means does not estimate that the vehicle will be stopped as it is, and the fuel cut can be returned, so that drivability is not impaired.

  The torque control apparatus for a hybrid vehicle according to the present invention includes a fuel cut means, a fuel cut return means, a vehicle stop estimation means, and a motor idle control means, each of which is realized by hardware. However, it may be realized by software constituting the flowchart shown in FIG.

  For example, as shown in FIG. 2, the fuel cut means is means for stopping fuel injection of the internal combustion engine when, for example, the accelerator opening is 0, and the fuel cut return means is, for example, vehicle speed or engine speed. Is a means for resuming that the fuel cut return condition is satisfied when the value is equal to or less than a certain value and restarting the fuel injection of the internal combustion engine. The vehicle stop estimation means, for example, decelerates as it is when the brake switch is operated. For example, the motor idle control means decelerates as it is when the brake switch is operated even when the fuel cut return condition is satisfied when the vehicle speed or the engine speed is below a certain value. If it is estimated that the engine will be stopped, the restart of fuel injection is prohibited and the internal combustion engine is idled by the electric motor. Further, when the idle stop condition is satisfied when the vehicle is stopped, for example, except when the battery capacity is low, the internal combustion engine may be stopped to improve the fuel efficiency when the vehicle is stopped.

A torque control apparatus for a hybrid vehicle according to an embodiment of the present invention will be described with reference to FIGS.
FIG. 1 is a flowchart of torque control, and FIG. 2 is a time chart for accelerator opening, vehicle speed, engine torque, and motor torque.

In this embodiment, as shown in FIG. 3, an engine (internal combustion engine) 1 and an electric motor (rotary electric machine) 2 are connected, and the power of the engine 1 is transmitted through a clutch 3 as a drive system (transmission). 4. Torque control of a 1-motor hybrid vehicle that does not have a motor traveling mode and is transmitted to a differential (deceleration / differential device) 5 and wheels 6.
This hybrid vehicle not only improves the fuel consumption by regenerating deceleration energy when decelerating, but also is an idle stop vehicle that stops idling when the vehicle stops.

That is, when the accelerator opening becomes 0, in order to improve fuel efficiency during deceleration, charging from the motor 2 to the battery 8 via the inverter 7 causes regeneration by the motor torque, while engine torque and vehicle speed decrease. When the fuel cut condition is satisfied, the fuel supply to the engine 1 is stopped (F / C). As a result, the engine torque becomes zero.
In order to ensure drivability, the regenerative power, which is the motor torque, is gradually reduced as the vehicle speed decreases.

When the vehicle speed further decreases and a fuel cut return condition (for example, the engine speed is 1000 rpm or less) is satisfied (step S1), it is determined whether or not a motor idle condition is satisfied to ensure drivability such as reacceleration. (Step S2).
The case where the motor idle condition is satisfied usually means that it is estimated that the vehicle will stop in this state. For example, the brake switch is operated, the clutch 3 is released, the manual transmission is neutral. And so on. Further, the case where the motor idle condition is not satisfied means a case where it is not known whether or not to stop as it is, such as coasting.

When the motor idle condition is satisfied, the fuel supply to the engine 1 is stopped (F / C), while the motor idle state is established by feedback controlling the torque so that the electric motor 2 rotates at the target idle speed. (Step S3).
As a result, the engine 1 is driven by the electric motor 2, and the fuel efficiency can be improved as compared with the case where fuel is supplied to the engine 1 and the engine is idling.

Subsequently, when the vehicle speed decreases and a vehicle stop condition (for example, vehicle speed = 0 km) is satisfied (step S4), it is determined whether or not an idle stop stop condition is satisfied (step S5).
For example, when the capacity of the battery 8 is reduced and the necessity for power generation is high, the idle stop stop condition is not satisfied.
When the idle stop stop condition is satisfied, the idle state by the electric motor 2 is stopped (step S6).

On the other hand, when the idle stop stop condition is not satisfied, the engine 1 is supplied with fuel from the idle state by the electric motor 2 to switch to the normal idle state (step S8).
On the other hand, at the time of re-acceleration, in step S2, the motor idle condition is not satisfied, the fuel supply to the engine 1 is resumed, and the fuel cut is restored (step S7).
Therefore, even if re-acceleration is performed in the motor idle state, the engine can be started early and good drivability is maintained.

  After returning from the fuel cut, as described above, in step S5, it is determined whether the idle stop stop condition is satisfied, and the idle state is stopped by the motor 2 (step S6), or fuel is supplied to the engine 1. Switching to the normal idle state (step S8).

As described above, in this embodiment, when it is estimated that the vehicle will be stopped as it is due to the motor idle condition in step S3, the fuel cut to the engine 1 is continued, and the electric motor 2 is driven at the target idle rotation. Feedback control.
For example, in the short time from deceleration to stop, the fuel cut is not returned, but the motor is driven to idle, so the fuel consumption is better than the fuel cut return.

In step S3, if it is unclear whether the vehicle will stop due to the motor idle condition, the fuel cut is resumed as usual.
In this case, there is a high possibility of re-acceleration, and it is not necessary to start the engine at the time of re-acceleration, and re-acceleration with high response can be performed.
Even if re-acceleration is performed while the motor is idling, the motor idling condition is not satisfied in step S3, and the engine can be started as soon as the fuel cut is restored, so that drivability is not impaired.

  The present invention can be used for a one-motor hybrid vehicle that does not have a motor running mode, and can also be used for an idle stop vehicle that stops idling when the vehicle stops.

It is a flowchart which shows the process of performing the torque control of the hybrid vehicle which concerns on one Example of this invention. It is a time chart about the accelerator opening at the time of performing torque control of the hybrid vehicle which concerns on one Example of this invention, a vehicle speed, an engine torque, and a motor torque. It is the schematic which shows the power train of the hybrid vehicle of 1 motor which does not have a motor drive mode applied to one Example of this invention. It is a flowchart which shows the process which performs the torque control of the hybrid vehicle which concerns on a prior art. It is a time chart about the accelerator opening at the time of performing torque control of the hybrid vehicle which concerns on a prior art, a vehicle speed, an engine torque, and a motor torque.

Explanation of symbols

1 Engine 2 Electric Motor 3 Clutch 4 Transmission 5 Differential 6 Wheel 7 Inverter 8 Battery

Claims (3)

A fuel cut means for cutting fuel to the internal combustion engine when the vehicle decelerates, a fuel cut return means for supplying fuel to the internal combustion engine when a fuel cut return condition for restarting fuel supply to the internal combustion engine is satisfied, and a vehicle When it is determined that the fuel cut return condition is established by the vehicle stop estimation means for estimating the stop of the vehicle and the fuel cut return means, and when the stop of the vehicle is estimated by the vehicle stop estimation means, the internal combustion engine is And a motor idle control means for prohibiting resumption of fuel supply and idling the internal combustion engine with an electric motor. 2. The torque control apparatus for a hybrid vehicle according to claim 1, wherein the vehicle stop estimation means is a brake switch. 2. The torque control apparatus for a hybrid vehicle according to claim 1, wherein the internal combustion engine is stopped when an idle stop condition is satisfied when the vehicle is stopped.

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