Cruise Control Predictive Downshift Avoidance
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Solution Overview
Problem
Existing cruise control systems experience unnecessary downshifts during uphill slopes, leading to fuel inefficiency, particularly when shifting from direct gears to gears with gear wheel pairs, as they fail to effectively manage vehicle speed and propulsion torque.
Innovation Solution
A method that predicts downshifts on upcoming uphill slopes by registering current vehicle conditions, including position, gear ratio, and road topography, allowing for the temporary lowering of downshift limits or increasing vehicle speed to a lowest safe speed to avoid or postpone downshifts, thereby maintaining optimal gear engagement and reducing fuel consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the cruise control system maintains a set target speed using conventional control methods, then the vehicle speed is stabilized, but unnecessary downshifts occur during uphill slopes causing fuel inefficiency
Solution Approach 1:
The control unit predicts upcoming uphill slopes using road gradient information before the vehicle actually encounters them. This preliminary prediction allows the system to prepare by adjusting vehicle speed or gear selection in advance, preventing unnecessary downshifts from occurring in the first place
Solution Approach 2:
The system continuously monitors actual vehicle speed, predicted road gradient, and current gear state, then adjusts control actions based on this feedback loop. The control unit modifies set speed or gear recommendations dynamically to maintain optimal fuel efficiency while ensuring speed stability
2Loss of energy
If the vehicle speed is increased to avoid downshifts on uphill slopes, then fuel efficiency improves, but the vehicle may exceed safe operating speeds
Solution Approach 1:
The system dynamically adjusts the downshift threshold speed parameter based on predicted road gradient and current vehicle state. By changing this parameter adaptively rather than using a fixed threshold, the system can allow higher speeds temporarily when approaching uphill sections, improving fuel efficiency while maintaining safety through continuous monitoring
3Loss of energy
If the downshift threshold is lowered to prevent unnecessary downshifts, then fuel efficiency improves, but the risk of excessive vehicle speed increases
Solution Approach 1:
The control unit uses predicted road gradient information to proactively adjust the downshift threshold before the vehicle encounters the uphill slope. This preliminary adjustment prevents unnecessary downshifts and maintains fuel efficiency while the system continues to monitor speed to prevent dangerous conditions
Solution Approach 2:
The downshift threshold is not a fixed value but a dynamic parameter that changes based on predicted road conditions, current vehicle speed, and gear state. This dynamic adjustment allows the system to optimize fuel efficiency while maintaining safety margins
Data Source
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AI summary
Method and cruise control system for controlling a vehicle cruise control comprising the steps of -driving said vehicle with said cruise control active and set to maintain a vehicle set target Speed (Vcc set target speed); -registering current vehicle condition, which comprises at least a current vehicle position (A), a currently engaged gear ratio, available gear ratios, current vehicle speed, available maximum propulsion torque and road topography of coming travelling road comprising a next coming uphill slope; - based on said current vehicle condition predicting a downshift at a coming vehicle position (C) in said coming uphill slope due to vehicle speed decrease and selecting at least one activity which results in that said downshift can be postponed or avoided; -controlling said cruise control according to said selected activity in order to postpone or avoid, for example a downshift from a direct gear and thereby saving fuel.