Electric Supercharger EGR System for Engine Responsiveness
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Solution Overview
Problem
Conventional exhaust gas recirculation systems face challenges in expanding the driving region for supplying recirculation gas, leading to increased manufacturing costs and limited design freedom in engine design, due to complexities in control logic and high costs associated with mechanical turbochargers and electric superchargers.
Innovation Solution
The engine system incorporates multiple electric superchargers and an exhaust gas recirculation device with a recirculation line branched from the exhaust manifold, joined to one of the intake lines, and a recirculation valve, allowing for expanded driving regions by controlling the operation of electric superchargers and intake valves to optimize recirculation gas supply.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a mechanical turbocharger is used to supply high-pressure air to the combustion chamber, then the combustion efficiency is improved, but the responsiveness is low and the design cost increases due to exposure to high-temperature exhaust gas
Solution Approach 1:
The patent replaces the mechanical turbocharger system with an electric supercharger system. The electric supercharger uses an electric motor to drive the compressor, eliminating the mechanical connection to the exhaust gas turbine. This substitution provides immediate responsiveness when power is applied, while avoiding exposure to high-temperature exhaust gas, thus resolving both the responsiveness and design cost issues while maintaining the air supply function.
2Quantity of substance
If a high pressure EGR system is used to supply recirculation gas using exhaust manifold pressure, then the recirculation gas supply is improved, but the driving region is limited when intake manifold pressure increases
Solution Approach 1:
The patent replaces the pressure-differential-based mechanical EGR system with an electrically-driven EGR system. The electric supercharger on the EGR line can actively pump recirculation gas regardless of pressure differences, enabling the system to operate across a wider range of driving conditions including high load scenarios where conventional HP-EGR fails.
Solution Approach 2:
The patent makes the EGR system dynamically adjustable through electric motor control. The EGR rate can be precisely controlled by adjusting the electric motor's power output, allowing the system to adapt to varying driving conditions and expand the operational driving region where recirculation gas can be effectively supplied.
3Quantity of substance
If a low pressure EGR system is used to supply recirculation gas from downstream of the exhaust gas purification device, then the recirculation gas is supplied, but the fresh air supply amount decreases and control logic becomes complicated
Solution Approach 1:
The patent segments the intake air supply into multiple independent paths: one path for fresh air through the turbocharger, and another path for recirculation gas through the electric supercharger. This segmentation allows independent control of each path, simplifying the overall control logic while maintaining the ability to supply both fresh air and recirculation gas simultaneously.
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 configuration enhances fuel efficiency by expanding the driving region for recirculation gas supply, improving vehicle fuel consumption and reducing manufacturing costs by simplifying control logic and design constraints.
Implementation Method 1
an electric supercharger having an impeller rotating about a rotation axis
Implementation Method 2
a diffuser extending in a radial direction about the rotation axis of the impeller and having a passage allowing the impeller to rotate therein
Implementation Method 3
an exhaust gas recirculation (EGR) device including a recirculation line branched from the exhaust manifold and joined to one of the plurality of intake lines
Data Source
AI summary
An engine system includes: an engine having a combustion chamber generating a driving torque by combust of a fuel; a plurality of intake lines through which outside air flows to the combustion chamber; an exhaust manifold connected to the combustion chamber at an exhaust side; at least two electric superchargers disposed on the plurality of intake lines, respectively; and an exhaust gas recirculation (EGR) system including a recirculation line branched from the exhaust manifold and joined to one of the plurality of intake lines and a recirculation valve disposed on the recirculation line.