Engine Control Device Combustion Mode Switching for PM Reduction
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Solution Overview
Problem
Conventional internal combustion engine control devices face challenges in reducing particulate matter (PM) in exhaust emissions due to fuel droplets depositing on combustion chamber walls, leading to incomplete combustion and increased PM formation when operating in premix burn mode by compression ignition.
Innovation Solution
A control device that adjusts fuel injection timing and mode based on engine body temperature, switching between intake stroke injection for homogeneous premix burn by flame propagation at lower temperatures, intake stroke injection for compression ignition at intermediate temperatures, and compression stroke injection for partial premix burn by compression ignition at higher temperatures to minimize PM formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If fuel is injected into the combustion chamber in the latter half of the compression stroke to enable premix burn by compression ignition, then fuel efficiency is improved, but fuel droplets deposit on the inside wall surfaces of the combustion chamber leading to increased PM in exhaust emissions
Solution Approach 1:
The patent applies dynamics by making the injection timing flexible rather than fixed. The control device dynamically adjusts injection timing based on engine operating conditions (temperature, load, speed). When wall temperature is sufficient, injection occurs in the latter half of compression stroke for high fuel efficiency. When wall temperature is low, injection timing is advanced to prevent droplet deposition, thus adapting injection strategy to real-time conditions to balance efficiency and emission control.
Solution Approach 2:
The patent changes the parameter of injection timing based on wall temperature conditions. By monitoring wall temperature and adjusting injection timing accordingly, the system optimizes the balance between fuel efficiency and PM emission control. This parameter adaptation allows the engine to operate in different injection modes (compression stroke injection for efficiency, earlier injection for emission control) depending on thermal conditions.
2Force
If injection pressure is raised to increase spray penetration force for fuel injection in the latter half of compression stroke, then fuel delivery is improved, but fuel more easily deposits as drops on the inside wall surfaces of the combustion chamber
Solution Approach 1:
The patent changes injection parameters (timing and pressure) based on wall temperature conditions. When wall temperature is low, the system adjusts injection timing to occur earlier in the compression stroke rather than in the latter half, even if this requires different pressure management. This parameter adaptation prevents droplet deposition while maintaining adequate fuel delivery, resolving the contradiction between spray penetration force and droplet deposition.
3Object-generated harmful factors
If fuel is injected in the intake stroke to form homogeneous premix for flame propagation burn, then PM emission is reduced, but fuel efficiency decreases compared to compression ignition
Solution Approach 1:
The patent applies dynamics by dynamically selecting between homogeneous premix burn (intake stroke injection) and compression ignition (compression stroke injection) based on wall temperature conditions. When wall temperature is low, homogeneous premix burn is used to control PM emissions. When wall temperature is high, compression ignition is employed to maximize fuel efficiency. This dynamic mode selection resolves the contradiction between emission control and fuel efficiency.
Solution Approach 2:
The patent changes the combustion mode parameter based on wall temperature. By switching between flame propagation (lower efficiency, lower PM) and compression ignition (higher efficiency, higher PM risk) depending on thermal conditions, the system optimizes the trade-off between PM emission and fuel efficiency across different operating conditions.
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 PM in exhaust emissions and improves fuel efficiency by optimizing combustion modes based on temperature thresholds, ensuring complete fuel evaporation and reducing wall deposits, thereby enhancing exhaust emission quality.
Implementation Method 1
feed fuel to the combustion chamber in the intake stroke to form a homogeneous premix
Implementation Method 2
form a homogeneous premix
Implementation Method 3
make the homogeneous premix burn by flame propagation
Implementation Method 4
feed fuel to the combustion chamber in the intake stroke to form a homogeneous premix
Implementation Method 5
form a homogeneous premix
Implementation Method 6
make the homogeneous premix burn by compression ignition
Implementation Method 7
directly feed fuel to the combustion chamber in the compression stroke to form a partial premix
Implementation Method 8
make the partial premix burn by compression ignition
Implementation Method 9
drops of fuel deposited on the inside wall surfaces of a combustion chamber etc. cannot be made to sufficiently evaporate
Implementation Method 10
cannot be made to sufficiently evaporate
Data Source
AI summary
A control device for an internal combustion engine is configured to feed fuel to a combustion chamber in an intake stroke to form a homogeneous premix and make the homogeneous premix burn by flame propagation when a temperature of an engine body is less than a first threshold value, to feed fuel to the combustion chamber in the intake stroke to form a homogeneous premix and make the homogeneous premix burn by compression ignition when the temperature of the engine body is the first threshold value to less than a second threshold value larger than the first threshold value, and to directly feed fuel to the combustion chamber in a compression stroke to form a partial premix and make the partial premix burn by compression ignition when the temperature of the engine body is the second threshold value or more.