Hill Start Clutch Torque Estimation via Accessory Load Compensation
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Solution Overview
Problem
Existing hill start assistance methods for motor vehicles often underestimate the clutch torque required for a safe hill start, leading to insufficient force applied to the drive wheels and potential backward movement of the vehicle.
Innovation Solution
A method and device that determine the clutch torque by accounting for the proportion of engine torque dedicated to the operation of vehicle components other than the clutch, using a balance of moments on the crankshaft and incorporating sensor data to accurately estimate the torque, ensuring sufficient force for a safe hill start.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If clutch torque is estimated without considering the proportion of engine torque dedicated to vehicle accessories, then the estimation process is simple, but the estimated clutch torque is insufficient leading to potential backward movement of the vehicle
Solution Approach 1:
The patent introduces computation means as an intermediary that calculates the proportion of engine torque dedicated to accessories (alternator, air conditioning, steering, etc.) and uses this information to adjust the clutch torque estimation. This intermediary processing ensures accurate torque estimation without requiring complex manual calculations or oversimplified assumptions.
Solution Approach 2:
The system continuously monitors engine torque requirements and adjusts the clutch torque estimation based on real-time accessory load conditions. The computation means processes current engine torque data and accessory requirements to provide feedback on the necessary clutch torque, ensuring the vehicle remains stationary during hill start assistance.
2Speed
If clutch torque is determined using conventional estimation methods, then the system response is fast, but the torque applied to drive wheels may be below the threshold needed to ensure safe hill start
Solution Approach 1:
The computation means performs preliminary calculations to determine the proportion of engine torque required for accessories before finalizing the clutch torque estimation. This preliminary action ensures that the clutch torque is adequately calculated in advance, preventing insufficient torque application during the critical hill start moment while maintaining fast system response.
3Ease of operation
If the brake is released when clutch torque exceeds a minimum threshold determined by conventional methods, then the hill start maneuver is facilitated, but the vehicle may experience backward movement due to insufficient clutch torque
Solution Approach 1:
The patent dynamically adjusts the clutch torque threshold parameter based on real-time accessory load conditions. Instead of using a fixed minimum threshold, the computation means calculates the appropriate threshold by considering the proportion of engine torque dedicated to accessories, ensuring the brake release timing is optimal for both maneuverability and vehicle stability.
Data Source
AI summary
A method for hill start assistance for a motor vehicle and to an associated device that includes a clutch and a transmission between the clutch and driving wheels of the vehicle. The method determines the torque of the clutch for maintaining the vehicle in an immobile position based on a known engine torque, wherein the torque of the clutch is determined by taking into account a portion of the engine torque dedicated to operation of constituent mechanisms of the vehicle other than the clutch.