JPH0974607A - Torque assist device for CVT vehicle - Google Patents

Abstract

(57) A torque assist device for a CVT vehicle capable of normally starting and traveling even when the CVT fails and is fixed in a high-side shift state. SOLUTION: When a fail detecting means included in a CVT / ECU 24 detects that the CVT 14 is a high-side fixed fail which is fixed in a high-side shift state, M / G / E
The vehicle speed determination means included in the CU 20 determines whether or not the vehicle speed after the high-side fixed fail detection is less than or equal to a predetermined speed. If the vehicle speed is less than or equal to the predetermined speed, the torque adjustment means included in the M / G / ECU 20 determines the accelerator opening and the vehicle speed. M / G12 depending on speed
In contrast, the increase amount ΔTref of the M / G torque command is determined, added to the normal M / G torque command, and the M / G torque command is output. It compensates for this and enables normal start / normal running even when the CVT 14 is fixed in the high-side shift state.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a torque assist device for a CVT vehicle, and more particularly to a torque assist device for compensating for a torque shortage when the CVT fails and is fixed in a high-side shift state.

[0002]

2. Description of the Related Art Conventionally, an induction machine (M / G;
A system has been proposed in which a motor / generator) is connected to supply electric power from a battery or a capacitor to function as a motor to perform torque assist during engine start and acceleration, and also to function as a generator during braking to recover electric power. ing. With such a system, it is possible to improve fuel efficiency by performing torque assist. In addition, as another means of improving fuel efficiency, from start to low speed,
CVT (Continuous Variabl) that shifts continuously up to high speed
Some vehicles have a transmission (continuously variable transmission) connected to the engine output shaft. The CVT uses a belt and a pulley and changes the groove width of the pulley to change the radius of the belt on the pulley, so that the gear ratio is continuously changed between the low and high gear ratios. By continuously controlling the gear ratio in this manner, the characteristics of the engine, which is an engine, can be fully utilized, and exhaust gas and fuel consumption can be improved.

Normally, such a CVT has a structure in which the gear shift state is forcibly fixed to the high side under the concept of fail safety when the control fails due to some cause and cannot be controlled. . For example, when a failure occurs in a hydraulic system that changes the groove width of the pulley, the groove width of the pulley is fixed to the high-side gear shifting state by a mechanical biasing means such as a spring, and when the vehicle is stopped or at a low speed. It is designed so that the large torque required for driving cannot be generated. As a result, a malfunction that the vehicle suddenly starts or suddenly accelerates when the CVT fails is avoided.

[0004]

However, even if the CVT is fixed to the high-side gear shift state due to a failure and the large torque required for stopping the vehicle or running at low speed cannot be generated, the failed vehicle can be promptly and safely operated. There is a demand to move to a place and preferably to normally travel to a repair shop.

The present invention has been made in view of the above conventional problems, and an object thereof is to allow a CVT vehicle to normally start and normally run even when the CVT fails and is fixed in a high-side shift state. Is to provide a torque assist device.

[0006]

In order to achieve the above object, a first invention is a torque assist device for a CVT vehicle, which assists an engine output by an electric motor connected between an engine output shaft and a CVT. In C., a fail detecting means for detecting a high-side fixed fail in which the CVT fails and enters a high-side shift state, and a vehicle speed judgment for judging whether or not the vehicle speed after the high-side fixed fail is below a predetermined speed Means and torque adjusting means for adjusting, by the output speed increase of the electric motor, the shortage amount with respect to the required torque that can be traveled in the high-side gear shift state when the vehicle speed determination means determines that the vehicle speed is less than or equal to the predetermined speed. Is characterized by.

Here, the predetermined speed means a minimum speed at which the CVT can travel while the high-side shift state is maintained, for example, 6
It is 0 km / h.

If the fail detecting means detects the high side fixed fail of the CVT and it is judged that the vehicle is in a low speed running state requiring a large torque or when the vehicle is stopped, the output of the electric motor added to the output torque of the engine. Increase the torque compared to normal torque assist. As a result, the start of the vehicle,
It becomes possible to make up for the shortage of the torque required for low speed running, and it is possible to perform normal start / normal running even when the CVT fails and is fixed in the high-side shift state.

In order to achieve the above object, a second invention is the first invention, wherein the torque adjusting means is
It is characterized by having an increase adjustment value table determined by the vehicle speed and the accelerator opening.

Even if the CVT fails and the CVT is in the high-side gear shift state, the torque adjusting means performs the optimum torque increase according to the accelerator opening and the vehicle speed. Therefore, smooth vehicle running is realized even when the CVT fails. At the same time, efficient torque assist that improves the fuel efficiency of the engine can be performed.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a block diagram of this embodiment. An M / G (motor / generator) 12 such as an induction machine that operates as an electric motor is connected to an engine output shaft of an E / G (engine) 10, and a CVT 14 is further connected. Then, the driving force generated by the E / G 10 or the M / G 12 is transmitted to the driving wheels 16. The state of the E / G 10 is monitored by the E / G-ECU 18, and the intake air temperature, engine speed, etc. are input to the E / G-ECU 18. On the other hand, the state of the M / G 12 is monitored by the M / G ECU 20. This M / G / ECU 20 is a CVT
Is normal, the M / G torque command value corresponding to the accelerator opening degree of the accelerator 22 is set to M / G as shown in FIG.
It supplies the G12 to the G12 and at the same time provides the E / G-ECU 18 with the information necessary to generate the drive command for the E / G10.
Furthermore, a CVT / ECU 24 that monitors the CVT 14 is connected to the M / G / ECU 20. CVT / EC
U24 is an optimum that can improve exhaust gas and fuel consumption based on a vehicle speed obtained from a vehicle speed sensor 26 connected to the M / G / ECU 20, a drive command for the E / G10 and an M / G torque command for the M / G12. The CVT 14 is controlled in various shift states. That is, the M / G-ECU 20 sets the E / G 10 at a predetermined ratio so that the output torque amount of the E / G 10 and the assist torque amount of the M / G 12 become the total torque amount corresponding to the accelerator opening degree of the accelerator 22. And M
/ G12 output is adjusted, and the CVT 14 is controlled to an optimum speed change state according to the accelerator opening (total torque amount) and the vehicle speed. As a result, the vehicle can run smoothly. At this time, for example, if 20% of the total torque amount corresponding to the accelerator opening is set to be torque assisted by the M / G 12, the E / G fuel efficiency of the vehicle is improved by 20% and the torque assist is performed. Exhaust gas can be reduced by just that much.

The characteristic feature of this embodiment is that CVT / EC
If U24 detects a failure of CVT14, in particular C
When the VT 14 detects a high-side fixed fail that is fixed in the high-side gear shift state, the motor function of the M / G 12 compensates for the insufficient torque with respect to the required torque that can be traveled in the high-side gear shift state.

The torque assist operation when the CVT 14 fails will be described below with reference to FIGS.

As described above, the CVT / ECU 24 is the CVT.
14 states are constantly monitored. The CVT / ECU2
The fail detecting means included in 4 recognizes various kinds of fail. However, as shown in the flowchart of FIG. 4, fail monitoring is performed particularly in a part for controlling the shift state, and the high side shift is performed based on the fail safety. The high-side fixed fail which becomes the state is detected (S100). When the high-side fixed fail is detected, the CVT / ECU 24 sets M /
A CVT fail signal is output to the G-ECU 20 (S101). If the fail is not the high-side fixed fail, an abnormal process corresponding to the fail, for example, an alarm is output. If the fail does not hinder the running, it is continuously monitored whether or not the high-side fixed fail occurs.

The M / G-ECU 20 also monitors the state of the M / G 12, and as shown in the flow chart of FIG.
It is always determined whether or not the CVT fail signal is input (S110). When the CVT fail signal is input, the vehicle speed determination means included in the M / G / ECU 20 determines, based on the information from the vehicle speed sensor 26, that the vehicle speed (V) after the high-side fixed fail detection is the predetermined speed (Vth).
It is determined whether or not the following (S111). The predetermined speed indicates the minimum speed at which the CVT 14 can travel in the high-side shift state, and is, for example, 60 km / h. When the vehicle speed (V) is higher than the predetermined speed (Vth), even if a high-side fixed fail occurs, the vehicle can travel in the high-side gear shift state without recognizing insufficient torque. M / G as in the normal CVT shown in (a)
A torque command is supplied to the M / G 12 (S112), and normal torque assist is performed.

On the other hand, when the vehicle speed determination means determines that the vehicle speed (V) after the failure is detected is smaller than the predetermined speed (Vth), for example, when the high side fixed failure occurs, the vehicle travels at a speed of 60 km / h or less. If the speed of the vehicle drops below 60 km / h after detecting the high-side fixed fail, or if the vehicle is stopped, it is normal to operate the vehicle while the CVT 14 is fixed in the high-side shift state. The torque is insufficient with the M / G torque command, and E / G
Will be stopped. Therefore, M / G · ECU20
The torque adjusting means included in the control unit performs control to increase the M / G torque command even when the accelerator opening is the same as when the CVT is normal, as indicated by the symbol (b) in FIG. 2 (S113). The increase amount ΔTref of the M / G torque command depends on the accelerator opening, but as shown in FIG. 3, it is required to increase as the vehicle speed decreases. That is, the increment ΔTre of the M / G torque command
f is determined by the vehicle speed (V) and the accelerator opening. For example, as shown in FIG. 3, the M / G-ECU 20 uses the table (c) showing the increment ΔTref of the M / G torque command with respect to the vehicle speed (V) when the accelerator opening is 100% and the accelerator opening 80%. A table corresponding to the accelerator opening (for example, 60% or 50% of the accelerator opening) like the table (d) showing the increase ΔTref of the M / G torque command with respect to the vehicle speed (V) at the time of I have more than one. Therefore, when performing the control to increase the M / G torque command in (S113), the M / G-ECU 20 selects a table according to the accelerator opening and uses the selected table to determine the M / G torque according to the vehicle speed. Determine the increment ΔTref of the command,
The increase ΔTref of this M / G torque command is set to the normal M /
It is added to the G torque command and supplied to the M / G 12.

After that, while the CVT fail signal is being input, the vehicle speed (V) is monitored in (S111), and the vehicle speed (V) and accelerator opening degree are maintained until a predetermined speed (for example, 60 km / h) or more is reached. The torque assist for adding the increment ΔTref to the normal torque command value is repeated by repeatedly determining the increment ΔTref of the M / G torque command.

Even when a high-side fixed fail occurs in the CVT 14 and a torque shortage that hinders the starting and running of the vehicle occurs in this manner, M will be changed according to the vehicle speed and the accelerator opening.
/ G12 torque can be increased to smoothly start and run.

In this embodiment, CVT · E
An example is shown in which the CU is provided with a fail detecting means for detecting a high side fixed fail of the CVT and a torque adjusting means at the time of fail is provided in the M / G / ECU, but the fail detecting means and the torque adjusting means are independent of each other. It may be provided.

[0021]

As described above, according to the present invention,
Even if a high-side fixed fail of the CVT occurs, the output torque of the electric motor is corrected according to the vehicle speed, so that the vehicle can be smoothly started and run without insufficient torque even when starting or running at low speed. Become.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a torque assist device for a CVT vehicle according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram illustrating a relationship between an accelerator opening degree and an M / G torque command of a torque assist device for a CVT vehicle according to an embodiment of the present invention.

FIG. 3 is a vehicle speed (V) and an M / G torque command increase amount Δ of a torque assist device for a CVT vehicle according to an embodiment of the present invention.
It is explanatory drawing explaining the relationship with Tref.

FIG. 4 is a flowchart illustrating a fail detection operation of the CVT / ECU of the torque assist device for a CVT vehicle according to the embodiment of the present invention.

FIG. 5 is a flowchart illustrating a torque assist operation of the M / G ECU of the torque assist device for a CVT vehicle according to the embodiment of the present invention.

[Explanation of symbols]

10 E / G (engine), 12 M / G (motor / generator), 14 CVT (continuously variable transmission), 16 drive wheels, 18 E / G · ECU, 20 M / G · ECU,
22 accelerator, 24 CVT / ECU, 26 vehicle speed sensor.

Claims (2)

[Claims] 1. A torque assist device for a CVT vehicle, which assists an engine output by an electric motor connected between an engine output shaft and a CVT, wherein a high side fixed fail in which the CVT fails and enters a high side shifting state. And a vehicle speed determining means for determining whether the vehicle speed after the high-side fixed fail detection is less than or equal to a predetermined speed, and a vehicle speed determining means for determining that the vehicle speed is less than or equal to a predetermined speed. The torque assist device for a CVT vehicle, further comprising: a torque adjusting unit that adjusts a shortage amount with respect to a required torque that can be traveled in a high-side gear shift state by increasing an output torque of the electric motor. 2. The torque assist device for a CVT vehicle according to claim 1, wherein the torque adjusting means has an increase adjustment value table determined by a vehicle speed and an accelerator opening degree. Vehicle torque assist device.