HCCI Engine Fuel Injection Control for Combustion Stability
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Solution Overview
Problem
HCCI engines face challenges in controlling combustion stability and preventing misfires or partial burns due to variations in cylinder temperature, especially during transients, leading to undesired drivability issues.
Innovation Solution
A control scheme that selectively activates a fast high-gain fuel injection correction algorithm based on combustion parameters like IMEP or NMEP to recover from and prevent misfires or partial burns by adjusting fuel injection in individual cylinders.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If HCCI engine operates with dilute fuel/air mixture and unthrottled to achieve diesel-like fuel economy, then fuel efficiency is improved, but combustion stability deteriorates leading to misfires or partial burns
Solution Approach 1:
The patent implements a feedback control system that monitors combustion stability and dynamically adjusts the fuel injection rate response characteristics. The ECU detects combustion events and modifies fuel injection parameters in real-time to maintain stable combustion while preserving the fuel economy benefits of dilute mixtures and unthrottled operation.
Solution Approach 2:
The patent introduces dynamic adjustment of the fuel injection rate response characteristic based on operating conditions. The system transitions between different response characteristics (e.g., aggressive vs. conservative fuel injection strategies) depending on detected combustion stability, allowing the engine to adapt to varying conditions while maintaining both efficiency and reliability.
2Reliability
If fast high-gain fuel injection correction algorithm is continuously activated to prevent misfires, then combustion stability is improved, but device complexity and computational load increase
Solution Approach 1:
The patent applies the fast high-gain fuel injection correction algorithm selectively rather than continuously. The system activates this aggressive correction strategy only when misfires or partial burns are detected, using normal control strategies during stable operation. This partial application reduces computational burden and control complexity while maintaining combustion stability when needed.
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
The solution effectively stabilizes auto-ignition combustion in HCCI engines by quickly correcting fuel injection, minimizing misfires and partial burns, and ensuring robust engine operation across varying conditions.
Implementation Method 1
Traditional compression ignition engines, such as diesel engines, typically function by introducing or injecting pressurized fuel into a combustion cylinder near top dead center (TDC) of the compression stroke, which ignites upon injection
Implementation Method 2
Combustion for both traditional gasoline engines and diesel engines involves premixed or diffusion flames that are controlled by fluid mechanics
Implementation Method 3
Controlled auto-ignition comprises a distributed, flameless, auto-ignition combustion process that is controlled by oxidation chemistry, rather than by fluid mechanics
Implementation Method 4
Because auto-ignition combustion is a distributed kinetically-controlled combustion process, an HCCI engine operates with a dilute fuel/air mixture (i.e., lean of a fuel/air stoichiometric point) and has a relatively low peak combustion temperature
Data Source
AI summary
There is provided a method and a control scheme to control an internal combustion engine operating in an auto-ignition mode by selectively activating a control scheme for controlling fuel injector operation based upon engine combustion parameters, e.g., IMEP or NMEP. The method comprises operating the engine in the auto-ignition combustion mode, and monitoring combustion in each of the cylinders. The fuel correction is selectively enabled only when either one of a partial burn and a misfire of a cylinder charge in one of the cylinders has been detected.