Engine Controller Ignition Timing for Low Piston Temperature
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Solution Overview
Problem
Existing engine control methods fail to effectively suppress the increase in Particulate Number (PN) emissions during acceleration when the piston top surface temperature is low, as they do not consider the suppression of Particulate Matter generation.
Innovation Solution
An engine controller that retards the ignition timing and extends the valve overlap period when the piston top surface temperature is low, reducing the contact time of the flame with any remaining liquid fuel and increasing internal EGR to evaporate and burn the fuel more efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If ignition timing is retarded to warm up the catalyst, then catalyst temperature increases, but PN emissions increase during acceleration when piston top surface temperature is low
Solution Approach 1:
The patent changes the ignition timing parameter dynamically based on operating conditions. When acceleration is detected and piston top surface temperature is low, the ignition timing is retarded by a specific amount (e.g., 10-30 degrees) to suppress PN emissions. This parameter adjustment resolves the contradiction by temporarily modifying combustion characteristics to reduce harmful emissions while maintaining warm-up functionality.
Solution Approach 2:
The patent implements dynamic ignition timing control that adapts to changing engine conditions. The system continuously monitors piston temperature and acceleration requests, adjusting ignition timing in real-time. This dynamic approach allows the system to optimize between catalyst warm-up and PN emission suppression based on current operating states, resolving the contradiction through adaptive control.
2Temperature
If stratified charge combustion is used for warm-up, then catalyst warm-up is effective, but PN generation cannot be suppressed during acceleration
Solution Approach 1:
The patent dynamically switches between combustion modes and adjusts ignition timing based on real-time detection of acceleration requests and piston temperature. During warm-up with acceleration requests and low piston temperature, the system uses modified combustion strategies with retarded ignition timing to suppress PN emissions while maintaining effective catalyst warm-up. This dynamic adaptation resolves the contradiction between warm-up efficiency and emission suppression.
3Productivity
If flame reaches piston top surface quickly, then combustion efficiency is high, but liquid fuel on piston top surface combusts and increases PN
Solution Approach 1:
The patent applies preliminary anti-action by retarding ignition timing before the flame can reach and combust liquid fuel on the piston top surface. By delaying ignition, the system prevents the harmful combustion of liquid fuel while still allowing efficient combustion of the air-fuel mixture. This timing adjustment creates a window that suppresses PN emissions from liquid fuel combustion while maintaining overall combustion efficiency.
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 effectively suppresses the increase in PN emissions by reducing the combustion of liquid fuel remaining on the piston top surface, thereby minimizing particulate matter generation and improving engine performance during acceleration.
Implementation Method 1
an ignition plug that spark-ignites a mixture in the cylinder
Implementation Method 2
a period of time until a flame after the ignition reaches the piston top surface is extended
Implementation Method 3
increasing internal EGR to evaporate and burn the fuel more efficiently
Data Source
AI summary
An engine controller controls a direct fuel-injection, spark ignition engine including a fuel injection valve configured to directly inject a fuel into a cylinder, and an ignition plug that spark-ignites a mixture in the cylinder. The engine controller is provided with an acceleration request sensor configured to detect an acceleration request of a driver, and when the acceleration request occurs and a top surface temperature of a piston in the cylinder is lower than a predetermined temperature, the engine controller retards an ignition timing so that a period of time until a flame after the ignition reaches the piston top surface is extended.