Data processing: vehicles – navigation – and relative location – Vehicle control – guidance – operation – or indication – Transmission control
Reexamination Certificate
1998-02-23
2001-01-09
Louis-Jacques, Jacques H. (Department: 3614)
Data processing: vehicles, navigation, and relative location
Vehicle control, guidance, operation, or indication
Transmission control
C701S053000, C701S054000, C701S058000, C477S125000, C477S105000, C477S110000
Reexamination Certificate
active
06173226
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a control apparatus and method for the powertrain of a vehicle having an engine or an electric motor and an automatic transmission, and a driving shaft.
Generally, in order to control precisely the powertrain of a vehicle, it is desirable to control it by using the driving shaft torque. In the prior art, because it is difficult to detect directly the driving shaft torque, the control of an automatic transmission is performed briefly by detecting the opening of a throttle valve for adjusting the amount of air taken into the engine of the vehicle, and the vehicle speed.
Recently, there is known a technique in which the driving shaft torque is calculated and estimated based on the characteristics of a torque converter using the speed ratio of the engine speed to the turbine speed as the parameters.
Because the control value is obtained from the opening of the throttle valve and the vehicle velocity, there is a problem that it is difficult to control precisely the transmission as compared with the method using the driving shaft torque. Further, In another method in which the driving shaft torque is calculated and estimated by using the characteristics of the torque converter, the driving shaft torque is calculated and estimated on the basis of the data table of the torque converter characteristics obtained by the experiments when the vehicle was developed. Therefore, even if the fluid in the torque converter deteriorates with age, the change in the torque converter characteristics may not be considered in the above method. As a result, the difference occurs between the calculated and estimated value of the driving shaft torque after the change with age and the actual value of the driving shaft torque. Accordingly, it is difficult to control precisely the transmission.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a control apparatus and a control method for a powertrain in a vehicle which can consider and correct a change of the powertrain with age, and improve the precision of the estimated value of the driving shaft torque.
In order to attain the above object, a control apparatus for a powertrain of a vehicle according to a first aspect of the present invention is provided with a drive unit which has an engine or an electric motor and an automatic transmission, and a driving shaft, and further comprises first torque estimating means for obtaining a first estimated driving shaft torque, second torque estimating means for obtaining a second estimated driving shaft torque used to correct said first estimated driving shaft torque, comparison means for comparing the first estimated driving shaft torque with the second estimated driving shaft torque, and driving shaft torque calculating means for calculating a driving shaft torque on the basis of the result of the comparison.
A control apparatus for a powertrain of a vehicle according to a second aspect of the present invention comprises first torque estimating means for obtaining a first estimated driving shaft torque, second torque estimating means for obtaining a second estimated driving shaft torque used to correct said first estimated driving shaft torque, learning and correcting means for comparing and learning said first estimated driving shaft torque with said second estimated driving shaft torque, and determining the start of the correction of said first estimated driving shaft torque.
In a control apparatus for a powertrain of a vehicle according to a third aspect of the present invention, the learning and correcting means determines the deviation between the first estimated drive shaft torque and the second estimated drive shaft torque each obtained at a first time point, determines the deviation between the first estimated driving shaft torque obtained by said first torque estimating means and the second estimated driving shaft torque obtained by said second torque estimating means each obtained at a second time point when the value of said second estimated driving shaft torque becomes equal to the value estimated at the first time point, detects the start of the correction when the difference between said first deviation and said second deviation became larger than a predetermined value, and corrects said first estimated driving shaft torque.
In a control apparatus for a powertrain of a vehicle according to a fourth aspect of the present invention, said first torque estimating means estimates the torque by using the characteristics of a torque converter.
It is desirable that the first torque estimating means estimates the torque by using the characteristics of the torque of the driving shaft, and comprises a torque sensor mounted on the driving shaft. Alternatively, the second torque estimating means estimates the torque by using signals detected from a vehicle weight detecting means and an acceleration detecting means.
Further, it is desirable that the second torque estimating means estimates a change in the vehicle weight by detecting when the vehicle speed is continuously equal to zero during a predetermined time period. The learning and correcting means inputs either one of a steering angle signal and a road condition detection signal (or both signals). A float signal for detecting the residual fuel is used as the road condition detection signal, or the learning and correcting means inputs a road condition detecting signal.
Furthermore, it is desirable that the road condition detecting signal uses a float signal for detecting the residual fuel in a fuel tank. In this case, the learning and correcting means inputs a steering angle to determine the start of the learning, and the learning and correcting applies an abnormality detecting signal such as an alarm signal from the outside.
According to another aspect of the present invention, a powertrain of a vehicle is provided with a drive unit which has an engine or an electric motor and an automatic transmission, and a driving shaft. The control apparatus comprises a vehicle speed detecting means for determining the stop of the vehicle, and a comparison means for comparing an acceleration for the output torque before the stop of the vehicle with that after the restart of the vehicle.
A control apparatus for a powertrain of a vehicle according to a further aspect of the present invention comprises vehicle weight calculating means for calculating the vehicle weight by using speeds and accelerations detected at different time points.
A control apparatus for a powertrain of a vehicle according to another aspect of the present invention comprises initial value storing means for storing the relationship between the acceleration of the vehicle and the driving shaft torque outputted by said drive means as an initial value.
In a preferred embodiment of the invention, the initial value storing means stores a first torque, and a torque calculating means determines a second torque. A torque comparing means compares the first torque with the second torque, and the said second torque is corrected by the relative value or the absolute value obtained in accordance with the result of the comparison by said torque comparing means.
In another preferred embodiment of the invention, the control apparatus for the powertrain of a vehicle according to the invention further comprises correction completion detecting means for detecting the completion of the correction of said second torque, and inhibition means for inhibiting the application of the second torque when the completion of the correction is not detected.
In still another preferred embodiment of the invention, the control apparatus for the powertrain of a vehicle further comprises initial value setting means for renewing the initial value of the first torque stored in the initial value storing means. The second torque is obtained by using the value renewed by the initial value setting means.
It is also desirable that the torque calculating means calculates the torque by using the characteristics of a torque converter obtained at different oil tempe
Ibamoto Masahiko
Kuroiwa Hiroshi
Masuda Mitsuhiro
Minowa Toshimichi
Yoshida Yoshiyuki
Evenson, McKeown, Edwards & Lenahan P.L.L.C.
Hitachi , Ltd.
Louis-Jacques Jacques H.
LandOfFree
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