Engine Combustion Control for EGR Stratification
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Solution Overview
Problem
Existing combustion control apparatuses fail to achieve effective stratification of EGR gas and fresh air in high engine load conditions, leading to inadequate NOx reduction and fuel consumption improvement.
Innovation Solution
A combustion control apparatus with a supercharger, fresh air blocking unit, and timing-controlled intake valves to ensure EGR gas stratification as the lower layer and air-fuel mixture or fresh air as the upper layer in the combustion chamber, even at high engine loads, by supercharging fresh air and controlling valve openings to maintain stratification during both intake and compression strokes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If fresh air is introduced through both intake ports and EGR valve opening is reduced to secure intake quantity at high engine load, then intake quantity is secured, but EGR gas and fresh air cannot be stratified and large quantity of EGR gas cannot be introduced
Solution Approach 1:
The intake system is divided into two separate intake ports: a first intake port for introducing EGR gas and a second intake port for introducing fresh air. This segmentation allows independent control of EGR gas and fresh air flow paths, enabling stratification even at high engine loads by preventing mixing at the intake stage.
Solution Approach 2:
Different regions of the combustion chamber are assigned different functions: the lower region receives EGR gas through the first intake port while the upper region receives fresh air through the second intake port. This local differentiation maintains stratification by creating distinct zones with different gas compositions throughout the combustion chamber.
2Object-generated harmful factors
If EGR gas is introduced in large quantity for NOx reduction and fuel consumption improvement, then NOx decreases and fuel consumption improves, but at high engine load the intake quantity becomes insufficient
Solution Approach 1:
By segmenting the intake system into dedicated EGR gas path and fresh air path, the system can introduce large quantities of EGR gas through the first intake port without compromising overall intake quantity, as the second intake port independently supplies sufficient fresh air.
Solution Approach 2:
The dual intake port system serves multiple functions simultaneously: the first intake port handles EGR gas introduction for emission control while the second intake port ensures sufficient fresh air supply for combustion, achieving both NOx reduction and maintained intake quantity at high engine loads.
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 allows for efficient stratification of EGR gas and air-fuel mixture, enabling a large quantity of EGR gas introduction while maintaining intake efficiency and reducing NOx emissions and improving fuel consumption, even under high engine load conditions.
Implementation Method 1
a supercharger that supercharges the fresh air at the upstream of the first intake passage and the second intake passage
Implementation Method 2
an BGR apparatus that circulates an EGR gas comprising a part of an exhaust gas into an EGR gas supply port provided at the first intake passage, from an exhaust passage of the internal combustion engine
Data Source
AI summary
An object of this invention is to provide a technology wherein a stratification of an EGR gas with an air-fuel mixture or a fresh air is achieved and capable of introducing the EGR gas in a large quantity, even when an engine load is high as an operation state of an internal combustion engine. With this invention, when a stratified combustion is performed by introducing the EGR gas, the fresh air is supercharged by a compressor, a fresh air blocking valve is closed to block inflow of the fresh air into a first intake port, and a variable valve mechanism opens a first intake valve before opening of a second intake valve, and, thereafter, opens the second intake valve.