Vehicle Propulsion Controller Torque Phase Ratio
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing vehicle propulsion systems experience imperceptible torque transients during gear shifts due to lagging indicators of mechanical advantage, requiring costly and complex calibration efforts to compensate for delayed ratio changes, leading to non-smooth axle torque transitions.
Innovation Solution
A controller generates a torque phase ratio based on the actual and commanded gear ratios, using clutch capacity feedback to linearly project the ratio change, allowing for more accurate and timely torque requests to the prime mover, thereby minimizing adverse transients and achieving smooth shifts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the gear ratio is calculated based on transmission input shaft speed sensor and output shaft speed sensor signals, then the gear ratio value can be obtained, but it becomes a lagging indicator of the actual change in mechanical advantage during shifts
Solution Approach 1:
The system calculates the torque phase ratio in advance during the torque phase (between clutch fill and clutch effectiveness) based on commanded gear ratios and timing, rather than waiting for the lagging speed sensor measurements. This preliminary calculation of the ratio change allows the prime mover control to anticipate and compensate for the mechanical advantage change before it fully manifests in the measured gear ratio, eliminating the time delay issue.
2Ease of operation
If additional compensation processes are implemented to anticipate gear ratio changes, then torque transients may be smoothed, but the system becomes more complex and requires workload intensive calibration
Solution Approach 1:
The system changes the parameter used for torque calculation from the measured gear ratio (which is lagging) to the torque phase ratio (which anticipates the change). By using the ratio of commanded gear ratios at the start and end of the torque phase, the system achieves smooth torque transitions without requiring complex calibration tables or workload-intensive compensation processes. The parameter change itself provides the necessary anticipation.
3Ease of operation
If torque management profiles are used to avoid torque transients, then torque management can be achieved, but it requires workload intensive calibration efforts and may not accurately reflect actual ratio change
Solution Approach 1:
The torque phase ratio calculation is self-service in that it directly computes the ratio change based on commanded gear ratios and timing information already available in the control system. It does not require external calibration tables or manual workload-intensive calibration efforts. The system uses its own internal parameters (commanded gear ratios at start and end of torque phase) to generate the compensation factor, making the process self-sufficient and eliminating the need for extensive calibration.
Data Source
AI summary
A propulsion system controller for a vehicle that includes a prime mover operable for generating an input torque on an input shaft, and a transmission connected to the prime mover that is configured to receive the input torque from the input shaft and produce an output torque on an output shaft. The controller is programmed to generate a torque phase ratio, and submit a torque request to the prime mover that is based upon a desired output torque divided by the torque phase ratio.