Adaptive Engine Torque Control for Fuel Economy
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Solution Overview
Problem
Motor vehicles, especially commercial vehicles, face inefficiencies in fuel usage due to excess engine performance when unladen or lightly laden, leading to poor fuel economy.
Innovation Solution
A method and system for controlling the engine of a motor vehicle by setting an acceleration limit based on the current gear ratio and estimated road load, and adjusting torque requests to reduce fuel consumption without compromising vehicle performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the engine is designed to provide adequate performance when the vehicle is fully laden, then the vehicle has sufficient acceleration capability when laden, but the engine produces excess performance and high fuel consumption when unladen or lightly laden
Solution Approach 1:
The patent applies dynamics by making the acceleration limit adaptive rather than fixed. The system continuously adjusts the acceleration limit based on real-time conditions including current gear ratio, engine rotational speed, and estimated road load. This dynamic adjustment allows the engine to provide high acceleration when needed (laden conditions) while automatically reducing acceleration capability when not needed (unladen conditions), thereby resolving the contradiction between maintaining acceleration capability and reducing fuel consumption.
Solution Approach 2:
The patent changes the parameter of acceleration limit based on operating conditions. By calculating a dynamic acceleration limit using the formula that incorporates gear ratio, engine speed, and road load estimation, the system modifies the acceleration parameter in real-time. This allows the engine to operate at optimal fuel efficiency points when the vehicle is unladen while still providing adequate acceleration when laden, thus resolving the energy consumption contradiction.
2Use of energy by moving object
If the acceleration limit is reduced to improve fuel economy when unladen, then fuel consumption decreases, but vehicle performance may be compromised
Solution Approach 1:
The system dynamically adjusts the acceleration limit rather than applying a fixed reduction. The acceleration limit is calculated based on current gear ratio, engine rotational speed, and estimated road load, ensuring that performance is maintained when actually needed while improving fuel economy when not needed. This dynamic approach prevents performance compromise because the system only limits acceleration when the calculated limit indicates it is safe to do so.
Solution Approach 2:
The system uses feedback from multiple sensors including gear position, engine speed, and road load estimation to continuously monitor vehicle conditions. This feedback loop allows the control system to make informed decisions about acceleration limiting, ensuring that performance is not compromised under conditions where full performance is still required, while achieving fuel economy improvements when conditions allow for limitation.
3Use of energy by moving object
If torque request is limited to reduce fuel usage, then fuel efficiency improves, but the demanded torque may not be met
Solution Approach 1:
The system changes the torque parameter dynamically by calculating a maximum torque request limit based on the acceleration limit, current gear ratio, and engine rotational speed. This parameter change ensures that torque is limited only when it would result in excessive fuel consumption, while still meeting demanded torque when the calculation shows it is appropriate to do so, thus maintaining reliability while improving fuel efficiency.
Solution Approach 2:
The system uses feedback from the driver's torque demand combined with feedback from vehicle operating conditions (gear ratio, engine speed, road load) to make intelligent torque limitation decisions. This feedback mechanism ensures that torque delivery reliability is maintained when the driver needs acceleration, while allowing fuel efficiency improvements when the feedback indicates the vehicle is operating in a condition where torque limitation is appropriate.
Data Source
AI summary
A method for controlling the operation of an engine of a vehicle is disclosed in which a torque request signal supplied to control the supply of torque from the engine is adaptively modified based upon a desired maximum acceleration limit for the currently engaged gear and variations in the sum of forces resisting motion of the vehicle.