Vehicle Slope Determination via Engine Decoupling
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Solution Overview
Problem
Current vehicle systems for determining road slope for load estimation in driving assistance systems, such as ABS, ESP, and ASR, are not precise and require additional costly sensors, increasing system complexity.
Innovation Solution
A method to determine road slope by measuring vehicle speed variation during engine decoupling from the transmission and using pre-established calibration curves or mathematical calculations, allowing for precise slope estimation without additional sensors, and subsequently calculating the vehicle's mass to correct load estimation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an inclination sensor is installed to determine road slope, then measurement precision of slope is improved, but device complexity and system cost increase
Solution Approach 1:
The system uses existing sensors (accelerometer, speedometer, wheel rotation sensors) already present in the vehicle to determine slope, rather than adding dedicated inclination sensors. The control unit processes data from these existing components to calculate slope information, making the system self-sufficient without additional hardware.
Solution Approach 2:
Existing sensors are made multi-functional by using them for multiple purposes. The accelerometer not only measures vehicle acceleration for basic vehicle dynamics but also determines road slope when combined with speed data during engine decoupling events. This universal use of existing components eliminates the need for dedicated slope sensors.
2Measurement precision
If additional sensors are added to improve slope determination, then measurement precision is improved, but manufacturing cost increases
Solution Approach 1:
The vehicle's existing sensor suite serves the additional function of slope determination, eliminating the need for manufacturers to procure and install expensive dedicated inclination sensors. This approach significantly reduces manufacturing costs while maintaining measurement precision through computational methods.
Solution Approach 2:
Instead of physically copying the function of inclination sensors through additional hardware, the system creates a computational model that replicates slope determination capabilities using mathematical processing of acceleration and speed data, providing a cost-effective alternative to physical sensor duplication.
3Device complexity
If existing sensors are used to determine slope without additional equipment, then device complexity is reduced, but measurement precision deteriorates
Solution Approach 1:
The slope determination process is segmented into distinct phases, utilizing specific time windows when the engine is decoupled from the transmission. During these brief intervals, the system processes sensor data with specialized algorithms tailored to the decoupling conditions, extracting precise slope information that would be difficult to obtain during normal driving operations.
Solution Approach 2:
The system dynamically adjusts its measurement and processing approach based on real-time operating conditions. It continuously monitors engine-transmission coupling status and activates slope determination algorithms specifically during decoupling events, adapting the measurement strategy to exploit transient conditions that provide clean slope data.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method provides a precise and economical determination of road slope and vehicle load, enhancing the accuracy and adaptability of ABS, ESP, and ASR systems to improve vehicle control and reduce stopping distances.
Implementation Method 1
The invention also comprises an acceleration sensor (A) arranged at the level of the vehicle and pointing in the direction of movement of the vehicle and forming a measurement value corresponding to the acceleration of the vehicle
Data Source
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AI summary
The vehicle has an engine, clutch and a monitoring unit for monitoring the rotational speed of wheels. A processing unit e.g. electronic stability program computer, measures the gradient of the vehicle by measuring the acceleration of the vehicle running along the gradient, when the engine is disengaged, where the mass of the vehicle is determined based on the measured gradient. A hydraulic control unit operates hydraulic brakes at the wheels to individually reduce the rotational speed when the speed exceeds a desired speed for ensuring that the vehicle follows the desired path of a driver.