HCCI Engine Fueling Strategy for Combustion Phasing Control
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Solution Overview
Problem
Existing engine control systems for recompression homogeneous charge compression ignition (HCCI) combustion struggle to regulate combustion phasing and fuel injection effectively, often requiring actuator settings that violate predetermined constraints, leading to suboptimal performance and potential violations of constraints such as pressure rise rates and emissions limits.
Innovation Solution
A method that adjusts valve actuation timing and fuel injection timing to control combustion phasing, using a closed-loop combustion phasing controller and fuel governor to determine and adjust fuel injection amounts based on estimated combustion state information, ensuring actuator settings comply with constraints, thereby achieving target combustion phasing and fuel injection amounts while avoiding constraint violations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the target fuel injection amount is determined based on commanded torque, then the engine can meet torque requirements, but the combustion phasing may deviate from target combustion phasing
Solution Approach 1:
The system uses closed-loop feedback control where combustion phasing is continuously monitored and used to adjust fuel injection timing. The combustion phasing controller receives feedback on actual combustion phasing and modifies injection timing to maintain the desired relationship between torque output and combustion phasing, resolving the conflict between meeting torque requirements and maintaining precise combustion control.
Solution Approach 2:
The system dynamically adjusts fuel injection timing based on real-time combustion conditions. Rather than using a fixed injection timing, the controller continuously modifies the injection timing to account for variations in combustion phasing, allowing the system to adapt to changing operating conditions while maintaining both torque output and combustion phasing control.
2Productivity
If valve actuation timing and fuel injection timing are regulated to achieve target combustion phasing, then combustion efficiency is improved, but actuator settings may violate predetermined constraints
Solution Approach 1:
The system performs preliminary checks to determine whether achieving target combustion phasing would require actuator settings that violate constraints. Before executing control actions, the controller evaluates whether the desired combustion phasing can be achieved within constraint boundaries, and only commands actuator movements that satisfy both performance and constraint requirements.
Solution Approach 2:
When target combustion phasing cannot be fully achieved due to actuator constraints, the system performs partial action by adjusting valve timing and/or injection timing to the maximum extent allowed by constraints. This provides the closest possible approximation to target combustion phasing while maintaining reliability through constraint compliance.
3Reliability
If fuel injection amount is adjusted to prevent actuator constraint violations, then reliability is improved, but combustion phasing control authority is reduced
Solution Approach 1:
The system uses multiple actuators (intake valve, exhaust valve, and fuel injection system) that can each contribute to combustion phasing control. When one actuator reaches its constraint boundary, other actuators can compensate to maintain combustion phasing control authority, distributing the control effort across multiple components to preserve both reliability and adaptability.
Data Source
AI summary
Methods and systems for controlling combustion performance of an engine during recompression HCCI combustion are provided. The method includes regulating a valve actuation timing and a fuel injection timing to cause a combustion phasing of at least one cylinder of the engine to approach a target combustion phasing, and estimating current combustion state information based on the combustion phasing. The current combustion state information includes at least one of a temperature, a pressure, and a pre-combustion charge composition associated with the at least one cylinder. The method further includes determining a target fuel injection amount, and determining whether the target fuel injection amount would require actuator settings that violate predetermined constraints in order to cause the combustion phasing to approach the target combustion phasing. A fuel injection amount is adjusted when the target fuel injection amount would require actuator settings that violate the predetermined constraints.