Vehicle Control Apparatus Torque-Based Inertia Phase Timing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The accuracy of determining the start timing of the inertia phase in a vehicle's automatic transmission is compromised when vehicle speed is low, leading to inaccuracies in calculating target engine torque due to deviations in detected rotation speeds of the input and output shafts.
Innovation Solution
A control apparatus that acquires input and clutch torques to determine the change from one state to another, calculating the target engine torque based on the intermediate gear ratio, thereby ensuring accurate determination of the inertia phase timing even at low vehicle speeds by focusing on torque changes rather than rotation speed accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If rotation speed sensors are used to detect input shaft and output shaft rotation speeds for determining inertia phase start timing, then the gear ratio can be calculated, but at low vehicle speeds the detected rotation speeds deviate from actual rotation speeds causing inaccurate start timing determination
Solution Approach 1:
The patent changes the parameter used for determining inertia phase start timing from rotation speed (which becomes inaccurate at low speeds) to acceleration. By using acceleration information instead of rotation speed information, the system maintains accurate start timing determination even when vehicle speed is low and rotation speed detection is unreliable.
2Speed
If the vehicle speed is low, then the number of teeth passing near the rotation speed sensor per unit time is reduced, but this causes the detected rotation speed to deviate from the actual rotation speed
Solution Approach 1:
The patent changes the measurement parameter from rotation speed to acceleration. Since acceleration can be accurately determined even at low speeds through torque calculations and clutch characteristics, this parameter substitution resolves the measurement precision problem that occurs at low vehicle speeds.
3Measurement precision
If the start timing of inertia phase is inaccurately determined, then the target engine torque calculation becomes inaccurate, but this deteriorates acceleration performance
Solution Approach 1:
By changing the basis for determining inertia phase start timing from rotation speed to acceleration, the patent ensures accurate start timing determination across all vehicle speeds. This accuracy directly improves target engine torque calculation, which in turn maintains optimal acceleration performance without deterioration.
Data Source
AI summary
A control apparatus includes an input torque acquisition unit acquiring an input torque input to an automatic transmission input shaft, a clutch torque acquisition unit acquiring a clutch torque of a clutch operated to change a gear stage of the transmission, a torque determination unit determining a change of the input torque and the clutch torque from a first state in which one of the input torque and the clutch torque is greater than the other to a second state in which the other one is greater than the one, a gear ratio calculation unit calculating an intermediate gear ratio between pre-shift and post-shift gear ratios, and a torque calculation unit, when the torque determination unit determines a change of the input torque and the clutch torque from the first state to the second state, executing a process of calculating a target engine torque based on the intermediate gear ratio.