Engine Speed Control via Feedforward Feedback Throttle Strategy
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Solution Overview
Problem
Existing engine speed control strategies face challenges in accurately predicting and controlling the relationship between throttle position and inlet manifold pressure, especially during transients, due to non-linear and unpredictable responses in gaseous fuel engines.
Innovation Solution
An engine speed control system that utilizes both feedforward and feedback control terms to calculate and adjust the throttle position based on target mass flow, accounting for desired pressure or density in the inlet manifold, incorporating a sensor to monitor pressure or density and an electronic control unit to calculate and command throttle position adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional throttle control strategies are used, then the control system is simple, but the control accuracy and responsiveness during transients deteriorate due to non-linear and unpredictable pressure responses
Solution Approach 1:
The patent implements a feedback control mechanism where the actual inlet manifold pressure is continuously measured and compared with the target pressure. The error signal is used to adjust the throttle position dynamically, ensuring accurate pressure control despite non-linear system behavior during transients.
Solution Approach 2:
The control system calculates a target inlet manifold pressure in advance based on desired engine operating conditions before actually adjusting the throttle. This preliminary determination of target pressure allows the system to proactively control the throttle position rather than reactively responding to pressure deviations.
2Speed
If aggressive throttle adjustment is used to improve responsiveness, then the speed of response improves, but system stability deteriorates due to overshooting and instability
Solution Approach 1:
The continuous feedback loop monitors actual pressure and dynamically adjusts throttle position, automatically dampening aggressive adjustments that would cause overshooting. The feedback mechanism inherently stabilizes the system by reducing the control action as the target pressure is approached.
Solution Approach 2:
The control system adapts its behavior dynamically based on operating conditions. During transient states, the system allows more aggressive throttle adjustments for faster response, while automatically transitioning to more conservative adjustments near the target pressure to maintain stability, creating a dynamic control strategy that balances speed and stability.
Data Source
AI summary
An engine speed control system for an internal combustion engine includes a throttle, and a sensor that monitors a parameter indicative of pressure or density of fuel and air in an inlet manifold of the engine. The electronic control unit is coupled with the throttle and the sensor and structured to calculate a target mass flow through the throttle, a feedforward control term based on the target mass flow, and a feedforward control term based on data produced by the sensor. The electronic control unit is further structured to vary a position of the throttle based on the feedforward and feedback control terms to adjust a mass flow through the throttle toward the target mass flow. The control system is applicable in throttle governed as well as fuel governed systems.