Engine Power Modulation via Periodic Acceleration Cycles
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Solution Overview
Problem
Internal combustion engines in vehicles often operate at less than maximum rated power for extended periods, leading to reduced fuel efficiency due to the need to accommodate varying driving conditions, which compromises vehicle performance when fuel economy is a priority.
Innovation Solution
A method that intermittently operates the engine at or near maximum rated power, alternating between acceleration and deceleration phases to maintain a target velocity, reducing fuel input during deceleration and preventing back-driving of the engine during deceleration, thereby optimizing fuel efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the engine is sized to meet maximum vehicle performance requirements, then vehicle performance is sufficient, but fuel efficiency deteriorates when operating at partial load
Solution Approach 1:
The system implements periodic acceleration and deceleration cycles, alternating between high-power operation at maximum engine power range and low-power operation during deceleration phases. This periodic action allows the engine to operate efficiently at partial load while maintaining the capability for maximum performance when needed.
Solution Approach 2:
The system dynamically changes engine operating parameters by adjusting fueling rates and selecting different torque/speed map zones based on whether the vehicle is in acceleration or deceleration phase. This allows optimization of fuel efficiency during deceleration while preserving maximum power capability during acceleration.
2Use of energy by moving object
If the engine operates at maximum rated power continuously, then fuel efficiency is improved, but vehicle velocity control deteriorates under varying driving conditions
Solution Approach 1:
The system dynamically adjusts engine operation between two distinct modes: maximum power range operation during acceleration phases and reduced power operation during deceleration phases. This dynamic adaptation allows the system to optimize fuel efficiency while maintaining appropriate velocity control for varying driving conditions through controller-mediated adjustments.
3Loss of energy
If the engine is allowed to back-drive during deceleration, then energy recovery is possible, but fuel efficiency deteriorates due to engine braking effects
Solution Approach 1:
The system extracts the harmful back-driving effect from the engine during deceleration phases by preventing the drive wheels from acting as a brake on the engine. This is achieved through controller-mediated fueling reduction and power flow path management, isolating the engine from the detrimental reverse torque while maintaining overall system efficiency.
Data Source
AI summary
A control strategy for a vehicle powered by an internal combustion engine has a repeating cycle of accelerating the vehicle during a more fuel efficient acceleration phase of the cycle followed by a deceleration phase of the cycle which uses little or no fuel.