Engine Control Device Catalyst Warm-Up PM Emission Reduction
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Solution Overview
Problem
Existing engine warm-up operations for catalyst activation are inefficient in reducing particulate matter (PM) emissions, as they do not effectively manage liquid fuel adherence to the piston crown surface, leading to increased PM discharge during cold starts.
Innovation Solution
An engine control device that performs a catalyst warm-up operation by injecting fuel during the compression stroke and advancing the fuel injection timing based on the estimated liquid fuel remaining on the piston crown surface, switching to lean stratified charge combustion when the liquid fuel amount exceeds a threshold, to minimize PM emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If homogeneous stoichiometric combustion is performed by retarding ignition timing during catalyst warm-up, then heating performance is improved, but PM emissions increase due to liquid fuel accumulation on piston crown surface
Solution Approach 1:
The ignition timing is dynamically adjusted between retarded timing (for heating) and advanced timing (for reducing fuel accumulation), allowing the system to transition between combustion modes based on operational requirements
Solution Approach 2:
The combustion mode is changed by altering the ignition timing parameter, switching between homogeneous stoichiometric combustion and stratified charge combustion to balance heating performance and emission control
2Temperature
If fuel is injected at compression stroke timing for catalyst warm-up, then heating performance is improved, but liquid fuel adheres to piston crown surface increasing PM discharge
Solution Approach 1:
The fuel injection timing is advanced to the intake stroke, allowing fuel to be injected earlier in the cycle before the piston reaches top dead center, preventing fuel accumulation on the piston crown surface while still enabling effective catalyst heating
Solution Approach 2:
The fuel injection timing parameter is changed from compression stroke to intake stroke, fundamentally altering when fuel is introduced into the cylinder to prevent adverse fuel accumulation effects
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 reduces the amount of liquid fuel remaining on the piston crown surface, thereby decreasing PM emissions and promoting catalyst warm-up while maintaining efficient combustion performance.
Implementation Method 1
a fuel is injected at a timing during the compression stroke, and at a timing when the fuel spray colliding with the piston crown surface moves toward the ignition plug along the shape of the piston crown surface
Implementation Method 2
an ignition plug configured to perform spark ignition for a gas mixture inside the cylinder
Implementation Method 3
a catalyst device for purifying an exhaust gas. The catalyst supported by the catalyst device
Data Source
AI summary
An engine control device controls a cylinder direct fuel injection type spark ignition engine provided with a fuel injection valve configured to directly inject fuel to a cylinder and an ignition plug configured to perform spark ignition for a gas mixture inside the cylinder. In a case where it is necessary to warm up an exhaust gas purifying catalyst disposed in an exhaust passage, the engine control device executes a catalyst warm-up operation in which a fuel is injected at a timing during the compression stroke, and at a timing when the fuel spray colliding with the piston crown surface moves toward the ignition plug along the shape of the piston crown surface, and in which the ignition timing is after compression top dead center. The engine control device advances the fuel injection timing in accordance with an increase in an estimation amount of a liquid fuel remaining on the top surface of the piston during execution of the catalyst warm-up operation.