Converter-Less Gear Shifting With Clutch Speed Synchronization
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Solution Overview
Problem
Existing automatic transmissions with torque converters experience reduced driveline efficiency due to torque multiplication and driveline torque disturbances during gear shifting and abrupt driver demand changes.
Innovation Solution
A method for shifting gears in a torque converter-less driveline by synchronizing the input and output speeds of a gear clutch and adjusting clutch torque to maintain a requested transmission output torque, using a controller to adjust torque source output and clutch pressure during the gear shift.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a torque converter is used in the transmission system, then torque multiplication is provided during some operating conditions, but driveline efficiency is reduced
Solution Approach 1:
The patent removes the torque converter from the transmission system, extracting the source of energy loss while maintaining torque multiplication capability through alternative means (electronic control of gear ratios and clutch engagement). This eliminates the parasitic losses inherent in torque converter operation while preserving the beneficial torque multiplication effect when needed.
Solution Approach 2:
The patent replaces the mechanical torque converter with an electronically controlled system that uses sensor inputs and processing logic to manage gear shifts and clutch engagement. This substitution eliminates the mechanical energy losses of the torque converter while achieving similar torque management objectives through electronic control algorithms.
2Productivity
If gear shifting is performed in traditional automatic transmissions, then gear changes are achieved, but driveline torque disturbances occur during shifting
Solution Approach 1:
The patent applies preliminary actions by pre-calculating and preparing clutch engagement torques and gear ratio transitions before actual gear shifting occurs. The electronic control system anticipates the need for gear changes and prepares the clutch and gear train in advance, smoothing the transition and preventing torque disturbances during the actual shift event.
Solution Approach 2:
The patent implements dynamic control of clutch engagement and gear ratio changes based on real-time operating conditions. The electronic control system continuously adjusts clutch torque and gear transition timing based on sensor inputs, creating a dynamic adaptation that maintains smooth operation during gear shifts and eliminates fixed, disturbance-prone shifting schedules.
3Power
If clutch torque capacity is increased to maintain requested transmission torque output, then torque transmission is improved, but driveline torque disturbances increase during speed synchronization
Solution Approach 1:
The patent applies partial action by using only the necessary amount of clutch torque required for smooth speed synchronization rather than maximum available torque. The electronic control system modulates clutch engagement to apply just enough torque to synchronize speeds and maintain output torque, avoiding excessive torque application that would cause disturbances during the synchronization phase.
Data Source
AI summary
A method and system for shifting gears of a converter-less transmission of a vehicle is described. In one example, torque output of a torque source is adjusted to synchronize input and output speeds of a gear clutch while a pressure of the gear clutch is adjusted to provide a desired or requested transmission output torque.