Cruise Control Torque Limiting for Fuel Savings Without Drivability Loss
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Solution Overview
Problem
Existing cruise control systems for heavy vehicles face challenges in balancing energy consumption and drivability, particularly when torque limitations are applied, which can impair vehicle performance and lead to driver dissatisfaction due to unexpected behavior.
Innovation Solution
A method that simulates vehicle speed profiles under torque limitations for upcoming road sections, activating the torque limitation only when it won't negatively affect drivability, and adjusting control parameters to maintain energy efficiency without compromising vehicle performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a torque limitation is applied to reduce energy consumption, then fuel efficiency is improved, but drivability is impaired
Solution Approach 1:
The control device performs simulations of vehicle speed profiles before actually traveling the upcoming road section to predict whether torque limitation will maintain drivability. This preliminary action allows the system to proactively apply torque limitation only when simulations confirm drivability requirements will be met, preventing the contradiction between energy savings and drivability
Solution Approach 2:
The torque limitation is made dynamic rather than static - it is applied selectively based on simulated outcomes for different upcoming road sections. The system dynamically adjusts whether torque limitation is active, transitioning between limited and unlimited torque states based on predicted drivability requirements, thus resolving the contradiction between consistent energy savings and context-dependent drivability needs
2Use of energy by moving object
If torque limitation is applied continuously, then energy consumption is reduced, but vehicle performance deteriorates
Solution Approach 1:
Torque limitation is applied locally to specific upcoming road sections rather than uniformly across all driving conditions. The control device simulates vehicle speed profiles for upcoming sections and applies torque limitation only where simulations indicate performance requirements will be satisfied, creating localized energy savings without global performance deterioration
Solution Approach 2:
The system changes the torque parameter dynamically based on simulated outcomes. Rather than maintaining a fixed torque limitation, the control device adjusts the torque parameter between limited and unlimited states based on whether simulations predict acceptable vehicle performance, thus achieving energy reduction without sustained performance loss
3Device complexity
If torque limitation is applied without simulation, then control simplicity is maintained, but driver satisfaction decreases
Solution Approach 1:
The control device performs self-service by automatically simulating vehicle speed profiles and making intelligent decisions about torque limitation application without requiring driver input or intervention. This self-service capability maintains control simplicity from the driver's perspective while internally executing complex simulations to ensure satisfaction, resolving the contradiction between apparent simplicity and actual performance
Data Source
AI summary
A control device and a method for controlling a cruise control system of a host vehicle are provided. The method comprises simulating vehicle speed of the host vehicle for an upcoming road section under a condition of a predetermined torque limitation (Tq_lim) being active, thereby determining a simulated vehicle speed profile for the host vehicle. The method optionally further comprises determining (S202) an estimated following distance profile, relative to a target vehicle, for the host vehicle for the upcoming road section based on the simulated vehicle speed profile for the host vehicle. The method also comprises, in response to a determination that the simulated vehicle speed profile for the host vehicle fulfils a first predefined condition or that the optionally determined estimated following distance profile fulfils a second predefined condition, activating (S104, S205) the predetermined torque limitation (Tq_lim), if not already active.