Vehicle Torque Control During Pull-Away Phase
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Solution Overview
Problem
Vehicles with manual transmissions face challenges during the pull-away phase, particularly on inclines or when laden, as drivers must balance clutch, brake, and accelerator pedals to avoid excessive clutch wear and engine stalling, leading to premature clutch replacement and emissions.
Innovation Solution
A method for controlling vehicle torque during the pull-away phase by monitoring torque demand and setting an engine output torque limit parameter, allowing the driver to manage torque transfer through the clutch while preventing excessive engine speed, thereby reducing clutch wear and emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the driver presses the accelerator pedal more firmly to prevent engine stalling during clutch engagement on inclines or when laden, then the engine speed is maintained, but excessive clutch wear occurs and emissions increase
Solution Approach 1:
The system dynamically adjusts the engine torque parameter during the pull-away phase by implementing a torque limit that is lower than the maximum engine torque capability. This parameter change prevents excessive torque transfer through the clutch while maintaining sufficient engine speed, thereby reducing clutch wear and emissions without causing engine stalling
Solution Approach 2:
The control system continuously monitors clutch engagement status and vehicle acceleration during the pull-away phase, using this feedback to dynamically adjust the torque limit. When clutch slip is detected or during the engagement phase, the system applies torque limiting to prevent excessive wear, and gradually reduces or removes the limit as engagement progresses
2Reliability
If a heavier duty clutch is fitted to reduce wear during high torque transfer, then clutch durability improves, but vehicle weight increases and transient response deteriorates
Solution Approach 1:
Instead of changing the physical characteristics of the clutch (weight, size, material), the system changes the operational parameter of torque transfer by implementing electronic torque limiting. This allows a lightweight clutch to achieve the durability of a heavier clutch by controlling the torque it must withstand during engagement
Solution Approach 2:
The invention replaces the mechanical solution of using a heavier duty clutch with an electronic control system that limits torque transfer. The control unit monitors engine torque and clutch engagement status, applying electronic torque management to protect the clutch, thereby substituting mechanical mass with electronic control
3Reliability
If the driver carefully balances the clutch and accelerator pedals to prevent excessive wear, then clutch life extends, but the ease of operation decreases and driver attention is required
Solution Approach 1:
The control system automatically monitors clutch engagement status and applies torque limiting without requiring driver intervention. The system self-adjusts the engine torque based on clutch slip detection and engagement phase identification, freeing the driver from the need to manually balance the clutch and accelerator pedals while still protecting the clutch from excessive wear
Solution Approach 2:
The system uses feedback from clutch position sensors, engine torque sensors, and vehicle acceleration data to automatically determine when torque limiting should be applied. This closed-loop control removes the need for driver skill and attention in balancing pedals, as the system autonomously manages torque transfer based on real-time feedback
Data Source
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AI summary
A method for controlling a vehicle which includes an engine and a driver-operable clutch. The method comprises identifying a pull- away phase of the vehicle; monitoring a torque demand parameter (accelerator pedal position); setting an engine output torque limit parameter indicating the output torque that the engine must not exceed during the pull-away phase (engine speed); and controlling the engine in dependence on the torque demand parameter and the engine output torque limit parameter. The torque demand parameter may be determined based on the driver-determined torque demand.