Internal Combustion Engine Combustion Control via Pressure Feedback
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Solution Overview
Problem
Direct-injection internal combustion engines operating in low-combustion-temperature combustion modes are sensitive to combustion instability and ringing, which can lead to poor combustion stability and engine damage due to uncontrolled ignition and noise, as they are affected by variations in CA50 timing and hardware variations.
Innovation Solution
A control routine in a controller monitors combustion pressure to determine combustion variation parameters like COV-IMEP and ringing index, adjusting the combustion heat release point by advancing or retarding fuel injection and spark ignition timing to maintain optimal combustion states, thereby controlling the timing of fuel injection and spark events to stabilize combustion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If direct-injection internal combustion engines operate in low-combustion-temperature combustion modes, then fuel efficiency and emissions are improved, but combustion instability and ringing occur leading to poor combustion stability
Solution Approach 1:
The system continuously monitors combustion pressure using a pressure sensor and calculates combustion variation parameters (COV-IMEP and ringing index). Based on these measurements, the controller dynamically adjusts fuel injection timing and spark ignition timing to maintain stable combustion while operating in low-combustion-temperature modes, creating a closed-loop feedback control system that resolves the contradiction between fuel efficiency and combustion stability
Solution Approach 2:
The system dynamically adjusts combustion parameters (fuel injection timing, spark ignition timing) in real-time based on measured combustion variation parameters. This dynamic adaptation allows the engine to maintain optimal combustion stability across varying operating conditions while preserving the fuel efficiency benefits of low-combustion-temperature operation
2Use of energy by moving object
If direct-injection internal combustion engines operate in low-combustion-temperature combustion modes, then fuel efficiency is improved, but ringing and noise occur leading to engine damage
Solution Approach 1:
The pressure sensor continuously measures combustion pressure and the controller calculates the ringing index in real-time. When ringing exceeds acceptable thresholds, the system provides feedback by adjusting fuel injection and spark ignition timing to suppress the harmful ringing and noise while maintaining low-combustion-temperature operation for fuel efficiency
Solution Approach 2:
The system uses the measured combustion variation parameters (including ringing index) not just to detect problems but to proactively adjust combustion timing parameters. By advancing or retarding injection and ignition timing based on ringing levels, the system converts the harmful ringing phenomenon into useful information for optimizing combustion control, thereby eliminating the harm while preserving fuel efficiency benefits
3Reliability
If combustion timing is adjusted to stabilize combustion, then combustion stability is improved, but complex control routines and monitoring are required
Solution Approach 1:
The system uses the engine's own combustion pressure measurements to automatically determine the appropriate control adjustments. The pressure sensor and controller work together to self-diagnose combustion stability issues and self-correct by adjusting injection and ignition timing, eliminating the need for external monitoring systems or complex manual control procedures
4Reliability
If real-time monitoring of combustion pressure is implemented, then combustion stability is improved, but additional sensors and control systems are required
Solution Approach 1:
The pressure sensor serves multiple functions: it monitors combustion pressure for stability assessment, calculates both COV-IMEP and ringing index parameters, and provides data for dynamic timing adjustments. This multi-functionality reduces the need for separate dedicated sensors and control systems, thereby improving combustion stability while minimizing the increase in device complexity
Data Source
AI summary
A direct-injection internal combustion engine is described and includes a pressure sensor that is disposed to monitor in-cylinder combustion pressure. A method, executed as a control routine in an attached controller, includes monitoring engine speed, engine load, temperature and combustion pressure. Combustion variation parameters are determined based upon the combustion pressure. A desired state for a combustion parameter can be determined based upon the engine speed, the engine load, and the temperature, and an adjustment to the desired state for the combustion parameter can be determined based upon the combustion variation parameters, wherein the adjustment to the desired state is selected to achieve acceptable states for the combustion variation parameters. Operation of the internal combustion engine is controlled based upon the desired state for the combustion parameter and the adjustment to the desired state for the combustion parameter.