Engine Control System Pressure-Based Valve Timing
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Solution Overview
Problem
Lean-burn gaseous fuel-powered engines face challenges due to variations in combustion pressures between cylinders, leading to uneven fuel distribution, increased risk of engine knock, and reduced load rating, as well as fluctuations in torque and speed, which can negatively impact electrical power generation.
Innovation Solution
A control system that includes sensors to monitor pressure within cylinders and a controller to adjust the timing of engine valves independently, allowing for precise regulation of fluid flow and combustion profiles to match a desired pressure profile, thereby balancing cylinder loading and reducing pressure variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If lean burn operation is implemented to increase fuel efficiency, then fuel efficiency is improved, but combustion pressure variations between cylinders increase
Solution Approach 1:
The patent divides the engine control into cylinder-specific segments, with each cylinder having its own pressure sensor and independently controllable valve actuator. This allows individualized control of each cylinder's combustion process, addressing the pressure variation problem while maintaining lean burn efficiency.
Solution Approach 2:
The patent applies local quality by implementing cylinder-specific pressure monitoring and independent valve timing control for each cylinder. This localized approach allows each cylinder to be optimized individually, maintaining uniform combustion pressures across all cylinders while operating in lean burn mode.
2Stress or pressure
If simultaneous combustion suppression in all cylinders is applied to limit excessive pressure, then excessive pressure is reduced, but engine output is unnecessarily reduced
Solution Approach 1:
The patent applies local quality by implementing cylinder-specific pressure monitoring and independent valve timing control for each cylinder. This localized approach allows each cylinder to be optimized individually, maintaining uniform combustion pressures across all cylinders while operating in lean burn mode.
Solution Approach 2:
The patent changes the control parameter from uniform combustion suppression to independent valve timing adjustment per cylinder. By modifying the timing parameter individually for each cylinder based on its pressure sensor feedback, the system maintains engine output while controlling combustion pressure variations.
3Device complexity
If uniform valve timing is used across all cylinders, then device complexity is reduced, but cylinder loading balance deteriorates
Solution Approach 1:
The patent divides the engine control into cylinder-specific segments, with each cylinder having its own pressure sensor and independently controllable valve actuator. This allows individualized control of each cylinder's combustion process, addressing the pressure variation problem while maintaining lean burn efficiency.
4Reliability
If margin of error is increased to accommodate pressure variations, then reliability is improved, but load rating is reduced
Solution Approach 1:
The patent implements feedback control by using pressure sensors in each cylinder to monitor combustion pressure and adjusting valve timing accordingly. This closed-loop feedback system maintains reliable operation by actively compensating for pressure variations, allowing the engine to operate closer to its load limit without sacrificing stability.
Data Source
AI summary
A control system for an engine having a first cylinder and a second cylinder is disclosed having a first engine valve movable to regulate a fluid flow of the first cylinder and a first actuator associated with the first engine valve. The control system also has a second engine valve movable to regulate a fluid flow of the second cylinder and a sensor configured to generate a signal indicative of a pressure within the first cylinder. The control system also has a controller that is in communication with the first actuator and the sensor. The controller is configured to compare the pressure within the first cylinder with a desired pressure and selectively regulate the first actuator to adjust a timing of the first engine valve independently of the timing of the second engine valve based on the comparison.