Vehicle Road Slope Estimation Using Sensor Offset and Driving Distance
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Solution Overview
Problem
Existing methods for estimating road slope in vehicles, either using driving torque or gravitational acceleration sensors, face inaccuracies when the vehicle is on a chassis dynamometer, leading to incorrect fuel consumption and power performance assessments.
Innovation Solution
A method and apparatus that determine an offset value for the gravitational acceleration sensor, calculate driving distance, and compare it with a predetermined value to decide between using driving torque or gravitational acceleration sensor for road slope estimation, ensuring accurate shift control and performance recognition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the gravitational acceleration sensor is used to estimate road slope, then measurement precision and responsiveness are improved, but reliability deteriorates when the vehicle drives procedure on a chassis dynamometer
Solution Approach 1:
The system changes the estimation method based on the detected driving state. When procedure driving is detected, it switches from gravitational acceleration sensor-based estimation to driving torque-based estimation, thereby adapting the measurement parameters to the current operating conditions and avoiding incorrect negative slope values.
Solution Approach 2:
The driving state detection function acts as an intermediary that determines which estimation method to use. It mediates between the gravitational acceleration sensor method and the driving torque method, selecting the appropriate one based on whether the vehicle is undergoing procedure driving or normal driving.
2Device complexity
If the driving torque method is used to estimate road slope, then device complexity is reduced, but measurement precision deteriorates due to driving torque changes
Solution Approach 1:
The system dynamically changes the estimation method based on driving state. During normal driving, it uses the simple driving torque method. During procedure driving, it switches to the more accurate gravitational acceleration sensor method, thereby optimizing measurement precision when needed while maintaining simplicity during normal operation.
3Speed
If the gravitational acceleration sensor method is used during chassis dynamometer testing, then responsiveness is improved, but reliability deteriorates causing incorrect shift control
Solution Approach 1:
The system changes the estimation approach based on detected driving state. When procedure driving on a chassis dynamometer is detected, it switches from the fast but inaccurate gravitational acceleration sensor method to the driving torque method, thereby preventing incorrect shift control while maintaining the ability to respond quickly during normal driving.
4Device complexity
If a single estimation method is used for all driving conditions, then device complexity is reduced, but measurement precision deteriorates under specific conditions
Solution Approach 1:
The system dynamically selects the estimation method based on the detected driving state. It transitions between the driving torque method and the gravitational acceleration sensor method depending on whether the vehicle is undergoing procedure driving or normal driving, thereby optimizing measurement precision for each specific condition while managing overall system complexity.
Solution Approach 2:
The system changes the estimation parameters based on driving conditions. During procedure driving, it uses driving torque-based estimation. During normal driving, it uses gravitational acceleration sensor-based estimation. This conditional parameter change ensures high precision across different operating conditions.
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 approach allows for precise estimation of road slope, enabling correct shift control and accurate fuel consumption and power performance recognition during chassis dynamometer tests.
Implementation Method 1
the method of estimating road slope by using the gravitational acceleration sensor detects a longitudinal acceleration when the vehicle is located on a slope
Data Source
AI summary
A method of estimating road slope of a vehicle may include determining an offset value of a gravitational acceleration sensor, determining a driving distance in a longitudinal direction of the gravitational acceleration sensor, comparing a difference between a driving distance and the driving distance in the longitudinal direction of the gravitational acceleration sensor with a predetermined value, estimating a road slope by using either a driving torque or the gravitational acceleration sensor based on a result of the comparison, and controlling a shift of the vehicle according to the estimated road slope.