Automatic automobile transmission with variable shift pattern controlled in response to estimated running load

Abstract

An automatic transmission control system for an automobile, comprising a vehicle weight estimation unit which estimates a vehicle weight of the automobile a torque estimation unit which estimates an output torque, an acceleration input unit which accepts an acceleration signal; a load estimation unit (110) which estimates a running load from the estimated vehicle weight, the estimated output torque and the accepted acceleration; a memory which stores a plurality of shift schedules therein; and a gear position determination unit (109) which includes the memory, and which selects one of the shift schedules in accordance with the vehicle weight and the estimated running load, so as to determine a gear position of an automatic transmission of the automobile in conformity with the selected shift schedule. An exact shift operation conformed to the vehicle weight and the running load can be performed, and an enhanced fuel consumption can be attained.

1. System for controlling selection of gear position for an automatic transmission of an automobile comprising:
 weight estimation means for estimating a total weight of said automobile;    acceleration input means for receiving an acceleration signal indicative of acceleration of said automobile;    output torque estimation means for estimating an output torque based on torque characteristics of a drive train of said automobile;    running load estimation means for estimating a running load from the estimated weight of the automobile, the acceleration, and the estimated output torque;    memory means for storing at least two shift schedules therein;    a shift schedule variable-control unit which determines a shift schedule of an automatic transmission of said drive train during actual running of said automobile on the basis of the estimated running load, the estimated weight of the automobile and the stored shift schedules; and    gear shift determination means for selecting a gear position of said automatic transmission based on the determination shift schedule;    wherein said output torque estimation means estimates said output torque based on torque characteristics of an engine of said drive train when a ratio between an input revolution speed and an output revolution speed of said torque converter is greater than a predetermined value, and based on torque characteristics of a torque converter of said automatic transmission when said ratio is less than said predetermined value.    
     
     
       2. System for controlling selection of gear position for an automatic transmission of an automobile, comprising:
 weight estimation means for estimating a total weight of said automobile;    acceleration input means for receiving an acceleration signal indicative of acceleration of said automobile;    output torque estimation means for estimating an output torque based on torque characteristics of a drive train of said automobile;    running load estimation means for estimating a running load from the estimated weight of the automobile, the acceleration, and the estimated output torque;    memory means for storing at least two shift schedules therein;    a shift schedule variable-control unit which determines a shift schedule of an automatic transmission of said drive train during actual running of said automobile on the basis of the estimated running load, the estimated weight of the automobile and the stored shift schedules;    gear shift determination means for selecting a gear position of said automatic transmission based on the determined shift schedule; and    a neural network which has stored therein values of at least a throttle valve opening and said acceleration of the automobile for learning values of a vehicle weight corresponding to the values of at least said throttle valve opening and said accelerations;    wherein said vehicle weight estimation means estimates said vehicle weight by time-serializing each of at least said throttle valve opening and said acceleration and then supplying resultant time-serial signals to said neural network.    
     
     
       3. An automatic transmission control system for an automobile as defined in  claim 2 , wherein said vehicle weight estimation means includes means for supplying said time-serial signals of said throttle valve opening and said acceleration, commencing when said throttle valve opening has exceeded a second predetermined value and said acceleration has also exceeded a third predetermined value. 
     
     
       4. System for controlling selection of gear position for an automatic transmission of an automobile, comprising:
 weight estimation means for estimating a total weight of said automobile;    acceleration input means for receiving an acceleration signal indicative of acceleration of said automobile;    output torque estimation means for estimating an output torque based on torque characteristics of a drive train of said automobile;    running load estimation means for estimating a running load from the estimated weight of the automobile, the acceleration, and the estimated output torque;    memory means for storing at least two shift schedules therein;    a shift schedule variable-control unit which determines a shift schedule of an automatic transmission of said drive train during actual running of said automobile on the basis of the estimated running load, the estimated weight of the automobile and the stored shift schedules; and    gear shift determination means for selecting a gear position of said automatic transmission based on the determined shift schedule;    wherein said vehicle weight estimation means estimates said vehicle weight of said automobile in response to a throttle valve opening signal and a vehicle speed signal in addition to said acceleration signal; and    wherein said output torque estimation means estimates said output torque in response to a revolution speed signal of an engine of said drive train and a turbine revolution speed signal of a torque converter of said automatic transmission.    
     
     
       5. System for controlling selection of gear position for an automatic transmission of an automobile, comprising:
 weight estimation means for estimating a total weight of said automobile;    acceleration input means for receiving an acceleration signal indicative of acceleration of said automobile;    output torque estimation means for estimating an output torque based on torque characteristics of a drive train of said automobile;    running load estimation means for estimating a running load from the estimated weight of the automobile, the acceleration, and the estimated output torque;    memory means for storing at least two shift schedules therein;    a shift schedule variable-control unit which determines a shift schedule of an automatic transmission of said drive train during actual running of said automobile on the basis of the estimated running load, the estimated weight of the automobile and the stored shift schedules; and    gear shift determination means for selecting a gear position of said automatic transmission based on the determined shift schedule;    wherein said output torque estimation means has a first mode in which said output torque is estimated from a turbine revolution speed of a torque converter of said automatic transmission and a revolution speed of an engine of said drive train, and a second mode in which said output torque is estimated from a throttle valve opening of said engine and said revolution speed of said engine, one of said first and second modes being selected in response to a ratio between an input and an output revolution speeds of said torque converter of said automatic transmission.    
     
     
       6. Method of controlling selection of gear position for automatic transmission of an automobile having means for storing a plurality of shift schedules for said automatic transmission, said method comprising the steps of:
 first, calculating an estimated weight of said automobile;    second, determining acceleration of said automobile;    third, calculating a value for an output torque of said transmission based on torque characteristics of a drive train of said automobile and generating an output torque signal indicative of said output torque value;    fourth, estimating a running load of said automobile based on said estimated weight of said automobile, the acceleration, and the output torque signal;    fifth, selecting a shift schedule from among a plurality of shift schedules stored in said means for storing, based on the estimated running load and the estimated weight of the automobile; and    sixth, selecting a gear position of said automatic transmission based on the selected shift schedule;    wherein said third step comprises calculating said output torque based on torque characteristics of an engine of said drive train when a ratio between an input revolution speed and an output revolution speed of a torque converter of said automatic transmission is greater than a predetermined value, and calculating said output torque based on torque characteristics of said torque converter of said automatic transmission when said ratio is less than said predetermined value.    
     
     
       7. Method of controlling selection of gear position for automatic transmission of an automobile having means for storing a plurality of shift schedules for said automatic transmission, said method comprising the steps of:
 first, calculating an estimated weight of said automobile;    second, determining acceleration of said automobile;    third, calculating a value for an output torque of said transmission based on torque characteristics of a drive train of said automobile and generating an output torque signal indicative of said output torque value;    fourth, estimating a running load of said automobile based on said estimated weight of said automobile, the acceleration, and the output torque signal;    fifth, selecting a shift schedule from among a plurality of shift schedules stored in said means for storing, based on the estimated running load and the estimated weight of the automobile; and    sixth, selecting a gear position of said automatic transmission based on the selected shift schedule;    wherein said third step comprises calculating said output torque based on at least torque characteristics of a torque converter of said automatic transmission, and torque characteristics of an engine of said drive train; and    wherein said third step comprises calculating said output torque based on said torque characteristics of the engine of said drive train when a ratio between an input revolution speed and an output revolution speed of said torque converter of said automatic transmission is greater than a predetermined value, and calculating said output torque based on said torque characteristics of said torque converter of said automatic transmission when said ratio is less than said predetermined value.    
     
     
       8. Control system for an automatic transmission with torque converter comprising:
   first input torque estimating unit for estimating an input - torque of said automatic transmission using an engine torque characteristic;        second input torque estimating unit for estimating an input - torque of said automatic transmission using torque - converter characteristic;        selecting unit for comparing the ratio between turbine revolution speed and engine revolution speed  ( Nt/Ne )  and a threshold value, selecting an estimated value from among estimated values from the first input - torque estimating unit and the second input - torque estimating unit in accordance with the comparison result, and outputting the estimated value selected as an estimated torque value, and        control unit for controlling the automatic transmission using the estimated torque value outputted from the selecting unit.     
     
     
       9. Control system for an automatic transmission with torque converter comprising:
   first input torque estimating unit for estimated an input - torque of said automatic transmission using an engine torque characteristic;        second input torque estimating unit for estimating an input - torque of said automatic transmission using torque - converter characteristic;        selecting unit for comparing the ratio between turbine revolution speed and engine revolution speed  ( Nt/Ne )  and a threshold value, selecting an estimated value from the first input - torque estimating unit when an ratio  ( Nt/Ne )  is not smaller than the threshold and selecting an estimated value from the second input - torque estimating unit when the ration  ( Nt/Ne )  is less than the threshold, and outputting the estimated value selected as an estimated torque value; and        control unit for controlling the automatic transmission using the estimated torque value from the selecting unit.     
     
     
       10. Control system for an automatic transmission with torque converter comprising:
   first input torque estimating unit for estimating an input - torque of said automatic transmission using an engine torque characteristic;        second input torque estimating unit for estimating an input - torque of said automatic transmission using an engine torque characteristic;        storing unit for comparing the ratio between turbine revolution speed and engine revolution speed  ( Nt/Ne )  and a threshold value, and memorizing a deviation of estimated values from the first input - torque estimating unit and the second input - torque estimating unit when the ratio  ( Nt/Ne )  is less than the threshold;        calculation unit for comparing the ratio between turbine revolution speed and engine revolution speed  ( Nt/Ne )  and a threshold value, and calculating an estimated torque value by correcting an estimated value from the first input - torque estimating unit using the memorized deviation when the ratio  ( Nt/Ne )  is not smaller than the threshold; and        control unit for controlling the automatic transmission using the estimated torque value from the calculating unit.