Accelerator Opening Degree Estimation for Hybrid Vehicle Sound Generation
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Solution Overview
Problem
Existing systems for generating engine sounds in vehicles, particularly those with electric or hybrid motors, face challenges in accurately detecting accelerator opening degrees without mounting sensors on the accelerator pedal, affecting operability and accuracy.
Innovation Solution
An apparatus that estimates accelerator opening degrees using a vehicle velocity detection device, a prime mover rotation detection device, and a storage section with pre-stored relationships between vehicle velocities and prime mover rotations, allowing for compensation of estimated values based on actual rotations detected, thus eliminating the need for sensors on the accelerator pedal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a sensor is mounted on the accelerator pedal to detect accelerator opening degree, then measurement precision is improved, but device complexity and ease of operation deteriorate
Solution Approach 1:
The patent uses the prime mover rotation number as an intermediary parameter to indirectly estimate the accelerator opening degree. Instead of directly measuring accelerator opening with a sensor, the system detects prime mover rotation number and uses it to infer accelerator opening degree through stored correspondence relationships, thereby avoiding direct sensor mounting on the accelerator pedal
Solution Approach 2:
The patent replaces the mechanical sensor-based detection system with an estimation system based on rotational dynamics. The accelerator opening degree estimation apparatus substitutes direct mechanical measurement with a calculation-based approach using prime mover rotation number and vehicle velocity to derive accelerator opening degree indirectly
2Device complexity
If prime mover rotation number is used to estimate accelerator opening degree, then device complexity is reduced, but measurement precision deteriorates
Solution Approach 1:
The patent incorporates feedback mechanisms by comparing estimated accelerator opening degree with actual vehicle behavior and adjusting the estimation accordingly. The system uses multiple parameters including vehicle velocity and prime mover rotation number in a comprehensive estimation process that adapts to actual operating conditions, improving measurement precision while maintaining simplicity
Solution Approach 2:
The patent changes the estimation parameters by using combinations of vehicle velocity and prime mover rotation number rather than relying on a single parameter. By storing and processing multiple parameter relationships in the storage section, the system achieves higher estimation accuracy without increasing device complexity
3Ease of operation
If accelerator opening degree is estimated without direct sensing, then ease of operation is improved, but reliability deteriorates
Solution Approach 1:
The patent makes the estimation system universal by using parameters (vehicle velocity and prime mover rotation number) that are already available in most vehicle systems. The stored correspondence relationships enable the system to function reliably across various operating conditions without requiring additional sensors or modifications to the accelerator control system
Solution Approach 2:
The patent applies preliminary action by pre-storing the correspondence relationships between vehicle velocity, prime mover rotation number, and accelerator opening degree before actual operation. This pre-computed data allows the system to quickly and reliably estimate accelerator opening degree during vehicle operation without real-time complex calculations, improving both reliability and response speed
Data Source
AI summary
During travel of a vehicle, an apparatus acquires vehicle velocity information detected by a vehicle velocity sensor and a reference accelerator opening degree and an estimated gear position from a reference accelerator opening degree table indicative of relationship between vehicle velocities and accelerator opening degrees during travel of the vehicle at cruising velocity. The apparatus also acquires an estimated number of prime mover rotations at the vehicle velocity from a vehicle-velocity vs. number-of-prime-mover-rotation correlation table, and then calculates a difference between the estimated number of prime mover rotations and an actual number of prime mover rotations detected by a number-of-prime-mover-rotation sensor. Further, a value, obtained by multiplying the calculated difference by a compensating coefficient determined in accordance with characteristics specific to the vehicle, is added to the reference accelerator opening degree, to thereby calculate an estimated accelerator opening degree.