Method for controlling an automatic transmission including predetermined time delay in shifting
First Claim
1. In a method for controlling an automatic transmission comprisinga plurality of frictional engaging elements arranged in frictional engagement for changing the state of transmission of engine power,a plurality of hydraulic servo mechanisms cooperated with the corresponding frictional engaging elements for independently engaging or releasing the frictional engaging elements, andelectronic control means for delivering control signals to the hydraulic servo mechanisms,said method comprising the step of independently engaging or releasing selected ones of said frictional engaging elements to change the power transmission state,the improvement wherein the delivery of a signal from the electronic control means to the hydraulic servo mechanism to operate one selected frictional engaging element is delayed a predetermined time from the delivery of a signal from the electronic control means to the hydraulic servo mechanism to operate another selected frictional engaging element, the other frictional engaging element taking a present state after having passed an antecedent state and being operated from the present to a subsequent state, andthe predetermined delay time being varied depending on the antecedent state of the other frictional engaging element preceding its operation.
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Accused Products
Abstract
The automatic transmission has clutches and brakes to change the gear ratio. The clutches and brakes are independently actuated by hydraulic servos. A hydraulic circuit supplies oil to and from the servos to either actuate or release them. Within the hydraulic circuit are solenoids which respond to an electronic control. The electronic control regulates the pressure in the hydraulic servos by supplying signals to the solenoids. By providing a predetermined time delay in the sending of a signal to the on-coming servo during a gear shift, a smoother shift can be achieved. The shift is further improved by varying the time delay by a predetermined value based on the previous condition of the off-going servo.
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Citations
10 Claims
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1. In a method for controlling an automatic transmission comprising
a plurality of frictional engaging elements arranged in frictional engagement for changing the state of transmission of engine power, a plurality of hydraulic servo mechanisms cooperated with the corresponding frictional engaging elements for independently engaging or releasing the frictional engaging elements, and electronic control means for delivering control signals to the hydraulic servo mechanisms, said method comprising the step of independently engaging or releasing selected ones of said frictional engaging elements to change the power transmission state, the improvement wherein the delivery of a signal from the electronic control means to the hydraulic servo mechanism to operate one selected frictional engaging element is delayed a predetermined time from the delivery of a signal from the electronic control means to the hydraulic servo mechanism to operate another selected frictional engaging element, the other frictional engaging element taking a present state after having passed an antecedent state and being operated from the present to a subsequent state, and the predetermined delay time being varied depending on the antecedent state of the other frictional engaging element preceding its operation.
- 9. The method of cliam 8 wherein the correcting time has a predetermined constant value.
Specification