Power-Based Engine Speed Control via Torque Domain Shift
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Solution Overview
Problem
Traditional engine control systems fail to accurately control engine output torque and do not provide rapid responses to control signals, leading to instability in controlling engine idle speed in the torque domain.
Innovation Solution
A control system comprising an engine speed control module, a fuel control module, and an air control module that adjusts fuel flow and air flow based on desired power, allowing for precise control of engine speed in the power domain, which is naturally stable, and coordinates torque control among various engine devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional engine control systems control engine idle speed in the torque domain, then torque control is achieved, but the system becomes unstable because engine speed must be continuously adjusted
Solution Approach 1:
The patent changes the control domain parameter from torque to power. By controlling engine speed in the power domain rather than the torque domain, the system achieves natural stability without continuous speed adjustments. The power-based control calculates desired power as a product of desired speed and desired torque, then controls fuel and air flow based on this power parameter, eliminating the instability inherent in torque-domain control.
2Power
If traditional engine control systems adjust throttle area and fuel injection to control torque output, then torque adjustment is achieved, but the response to control signals is slow
Solution Approach 1:
The system performs preliminary calculation of desired power based on desired speed and desired torque before executing control actions. By pre-calculating the required fuel mass and air flow based on the power demand, the system prepares control commands in advance, enabling faster response to control signals compared to traditional sequential adjustment methods.
3Speed
If traditional engine control systems use air flow control in spark-ignition engines or fuel flow control in compression-ignition engines for idle speed control, then idle speed control is achieved, but torque control accuracy is insufficient
Solution Approach 1:
The patent implements a universal power-based control approach that works for both spark-ignition and compression-ignition engines. The system calculates desired power and controls both fuel flow and air flow simultaneously based on this power parameter, making the control strategy engine-type independent while improving both idle speed control and torque control accuracy compared to traditional single-parameter control methods.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables stable engine speed control, reducing error correction needs and allowing for efficient maintenance of desired engine speeds, including idle speed, while quickly adapting to changes in load conditions.
Implementation Method 1
Internal combustion engines combust an air and fuel mixture within cylinders to drive pistons, which produces drive torque
Data Source
AI summary
A control system includes an engine speed control module, a fuel control module, and an air control module. The engine speed control module controls an actual speed of an engine based a desired power to be generated by combustion in the engine, wherein the desired power is a product of a desired speed of the engine and a desired torque output of the engine. When operating in a fuel lead mode, the fuel control module controls fuel flow in the engine by adjusting a desired fuel mass for each activated cylinder of the engine based on the desired power. The air control module controls air flow in the engine based on an actual air/fuel ratio of the engine resulting from the desired fuel mass.