Vehicle Control for Low-Speed Stop-Start Suppression
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Solution Overview
Problem
In vehicles equipped with engine stop-restart systems and four-wheel drive transfers, the engine stop-restart system causes instability and increased fuel costs when switched to low range mode, especially on off-road surfaces, and current solutions either prohibit engine stop-start on all road types or require costly sensors to differentiate between off-road and on-road conditions.
Innovation Solution
A control device using a vehicle speed sensor to identify low-speed travel sections and determine if they exceed a prescribed number of times, thereby determining if low-speed travel is inevitable, allowing the engine stop-restart system to be prohibited in such situations without the need for expensive sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the engine stop-restart system is prohibited when the transfer is switched to the low range mode, then vehicle stability is improved, but fuel costs increase
Solution Approach 1:
The control device applies different control strategies to different driving situations by analyzing vehicle speed patterns. When low-speed sections are detected (indicating off-road conditions), the engine stop-restart system is prohibited to maintain stability. When high-speed sections are detected (indicating on-road conditions), the system allows engine stop-restart to reduce fuel consumption. This localized control approach resolves the contradiction by adapting the engine control strategy to the specific driving context.
Solution Approach 2:
The system dynamically adjusts engine control based on real-time vehicle speed data and travel pattern analysis. The control device continuously monitors vehicle speed and determines whether the vehicle is in low-speed or high-speed travel sections, then dynamically switches between prohibiting and allowing the engine stop-restart system accordingly. This dynamic adaptation resolves the contradiction between stability and fuel efficiency.
2Measurement precision
If expensive sensors or cameras are used to measure vehicle behavior and distinguish off-road and on-road conditions, then determination accuracy is improved, but manufacturing cost increases
Solution Approach 1:
The control device utilizes vehicle speed data that is already being collected by the vehicle's existing speed sensor for other control functions. By analyzing this existing data to determine travel sections (low-speed vs. high-speed), the system achieves accurate off-road/on-road differentiation without requiring additional expensive sensors or cameras. This self-service approach resolves the contradiction between measurement precision and manufacturing cost.
Solution Approach 2:
The vehicle speed sensor serves multiple functions: it provides speed data for basic vehicle control and simultaneously enables the determination of travel sections for engine stop-restart control. This multi-functionality eliminates the need for dedicated expensive sensors, resolving the contradiction between accurate measurement and manufacturing cost.
Data Source
AI summary
An electronic control unit is a control device for controlling a vehicle including a vehicle speed sensor. The electronic control unit is configured to identify a section from start to stop of the vehicle using a vehicle speed detected by the vehicle speed sensor, determine whether the number of times of a low-speed section is more than a prescribed number of times, the low-speed section being the identified section where a representative value of the vehicle speed is less than a prescribed speed, and determine that the vehicle is in a specific situation where low-speed travel is inevitable, when it is determined that the number of times of the low-speed section is more than the prescribed number of times.