Clutch Actuator Control for Variable Engine Loads
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Solution Overview
Problem
In vehicles with a two-pedal system, variable engine loads due to power take-off upstream of the clutch cause unpredictable clutch behavior, leading to discomfort and loss of precision during driving, especially in applications requiring precise control like hook loaders.
Innovation Solution
A method that adjusts the clutch actuator's position based on feedback from monitored engine torque, switching between feedback control and open control when additional engine consumers are activated or deactivated, maintaining a predetermined relationship between clutch torque and actuator closure to ensure consistent driver experience.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If feedback control is used to regulate clutch actuator position based on engine torque, then the clutch torque can be precisely controlled under normal conditions, but the vehicle behavior becomes unpredictable and uncomfortable when variable loads are applied upstream of the clutch
Solution Approach 1:
The control system dynamically switches between feedback control mode and open control mode based on the operating conditions. When variable loads are detected upstream of the clutch, the system transitions from feedback control to open control, where the clutch actuator position is regulated based on predetermined relationships rather than torque feedback, thereby maintaining predictable vehicle behavior under varying load conditions
2Measurement precision
If the clutch actuator position is regulated based on torque feedback to maintain set-point clutch torque, then precise torque control is achieved, but the clutch actuator position changes in response to unknown disturbances causing driver discomfort
Solution Approach 1:
The control system dynamically adjusts its operation mode based on detected load conditions. When variable loads are detected, the system switches from feedback control to open control, using predetermined relationships between accelerator pedal position and clutch actuator position rather than torque feedback, thereby eliminating unexpected position changes that cause driver discomfort
Solution Approach 2:
The invention extracts the torque feedback element from the control system when operating under variable loads. By removing the feedback control mechanism during these specific conditions and replacing it with open control based on predetermined relationships, the system eliminates the source of unpredictable behavior while maintaining simplicity and driver comfort
3Power
If feedback control opens the clutch to lower torque when power take-off load increases, then engine torque management is maintained, but the force driving the powered wheels decreases and vehicle speed is reduced
Solution Approach 1:
The control system dynamically switches to open control mode when variable loads are detected, using predetermined relationships between accelerator pedal position and clutch actuator position. This prevents the automatic clutch opening that would occur under feedback control, thereby maintaining the force driving the powered wheels and preventing unwanted reduction in vehicle speed during moving off
4Power
If the clutch actuator closes automatically when power take-off load decreases, then torque balance is maintained, but a jerk is caused in the power train
Solution Approach 1:
The control system dynamically switches to open control mode when variable loads are detected, using predetermined relationships rather than torque feedback. This prevents the automatic clutch closing that would occur under feedback control when load decreases, thereby eliminating the jerky movements in the power train and ensuring smooth operation
Data Source
Figure 1~2
Figure 3
Figure 4a~4b
AI summary
The invention relates to a method, a device and a computer programme for control of a motor vehicle's propulsion whereby a clutch torque (Req T) is demanded by a driver by activation of an accelerator pedal, the degree of closure (G) of the vehicle's clutch actuator is controlled by feedback on the basis of a monitored engine torque and there is at least one further consumer (290) of engine power in addition to said propulsion. The method comprises the steps of detecting (s410) activation of said at least one further consumer and, when such activation is detected, changing (s420) said feedback control to open control whereby the degree of closure (G) of the vehicle's clutch actuator is based on a predetermined relationship between said degree of closure (G) and the clutch torque (Req T), which clutch torque (Req T) is demanded by the driver by a activation of an accelerator pedal.