Prechamber Heating for Cold-Start Emission Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Internal combustion engines with fuel-fed prechambers face challenges in reducing cold-start emissions, particularly particle emissions, due to incomplete prechamber combustion and fuel deposits at low temperatures, leading to adverse ignition conditions and high emissions during engine start.
Innovation Solution
A control unit and method that perform a prechamber heating operation by injecting a predetermined amount of fuel into the prechamber and igniting it before the main combustion, allowing for sufficient evaporation and mixing with air, thereby improving ignitability and reducing particle emissions. This involves deactivating the main fuel injector during the first engine cycle to optimize prechamber combustion timing and temperature, with multiple heating operations if necessary, to ensure the prechamber wall reaches a sufficient temperature for efficient ignition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If fuel is injected into the prechamber at low temperature during engine start, then the prechamber combustion is intended to heat the prechamber wall, but the fuel accumulates on the prechamber wall (wall wetting) and cannot evaporate properly, resulting in incomplete combustion and high emissions
Solution Approach 1:
The system performs a preliminary prechamber heating operation by injecting a first amount of fuel into the prechamber and igniting it before the main combustion cycle begins. This preliminary action heats the prechamber wall to a temperature sufficient to prevent wall wetting during subsequent fuel injection, thereby eliminating the technical contradiction between heating the wall and avoiding harmful emissions.
2Reliability
If the engine operates at low temperature during cold start, then the engine can be started, but the fuel injected into the prechamber cannot evaporate properly leading to incomplete combustion
Solution Approach 1:
The control unit executes a preliminary prechamber heating operation before the main combustion cycle to raise the prechamber wall temperature. This preliminary heating ensures that when fuel is injected during the main combustion cycle, the wall temperature is sufficient for proper evaporation and combustion, thereby simultaneously improving ignition reliability and reducing emissions.
3Object-generated harmful factors
If multiple prechamber heating operations are performed to ensure sufficient wall temperature, then emissions are reduced, but the engine start process takes longer
Solution Approach 1:
The control unit dynamically adjusts the amount of fuel injected into the prechamber and the number of heating operations based on the measured engine temperature. At lower temperatures, more heating operations or larger fuel amounts are used to ensure sufficient wall heating. As the engine temperature rises, the fuel amount and number of operations are reduced, thereby minimizing the time loss while still achieving the emission reduction goal.
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 prechamber heating operation significantly reduces particle emissions and ensures reliable ignition and combustion in the main combustion chamber, even at low engine temperatures, by generating reactive jets and avoiding wall wetting, thus improving starting performance and compliance with cold emission tests.
Implementation Method 1
the fuel injected into the prechamber cannot evaporate properly but accumulates on the prechamber wall (wall wetting)
Implementation Method 2
igniting the resulting air-fuel mixture therein. Since the prechamber is connected to the main combustion chamber via multiple small orifices, the combustion inside the prechamber results in multiple reactive jets
Implementation Method 3
the combustion inside the prechamber results in multiple reactive jets, which enter from the prechamber into the main combustion chamber and ignite the air-fuel mixture therein
Data Source
AI summary
The present invention relates to a device and a method for controlling the start of an internal combustion engine, wherein the internal combustion engine is equipped with an ignition device comprising a fuel-fed prechamber to ignite an air-fuel mixture in a main combustion chamber. In order to reduce the emissions of the internal combustion engine during engine start a prechamber heating operations is performed by injecting a predetermined amount of fuel into the prechamber and igniting an air-fuel-mixture therein, while the main fuel injector is deactivated during at least a first engine cycle after engine start request.