Hybrid Engine EGR Control with Electric Superchargers
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Solution Overview
Problem
Conventional exhaust gas recirculation systems in hybrid electric vehicles face limitations in expanding the operation region for recirculating gas supply, leading to increased manufacturing costs and reduced design freedom due to low responsiveness and high back pressure of mechanical turbochargers, as well as complex control logic and limited NOx emission reduction.
Innovation Solution
The engine system incorporates a hybrid configuration with two electric superchargers, a dual EGR device setup, and a controller that adjusts torque and camshaft operation to expand the recirculating gas supply region, utilizing bypass lines and intercoolers to optimize air pressure and recirculation efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a mechanical turbocharger is used to increase combustion efficiency, then the engine output is improved, but the responsiveness is low and back pressure is high
Solution Approach 1:
The patent divides the supercharging function into two separate electric superchargers (first and second electric superchargers) instead of using a single mechanical turbocharger. This segmentation allows independent control of each supercharger, improving responsiveness while maintaining engine output through coordinated operation.
Solution Approach 2:
The patent replaces the mechanical turbocharger system with an electric supercharger system. The electric superchargers are driven by electric motors rather than exhaust gas pressure, eliminating the mechanical coupling that causes high back pressure and improving responsiveness through direct electric control.
2Power
If a mechanical turbocharger is used to increase combustion efficiency, then the engine output is improved, but the back pressure is high
Solution Approach 1:
The patent replaces the mechanical turbocharger system with an electric supercharger system. The electric superchargers are driven by electric motors rather than exhaust gas pressure, eliminating the mechanical coupling that causes high back pressure while maintaining the ability to supply high-pressure air for combustion.
Solution Approach 2:
The patent introduces electric motors as intermediary devices between the power source and the air compression function. These electric motors drive the supercharger compressors independently of the exhaust gas flow, mediating the power transmission to avoid the direct mechanical coupling that creates high back pressure in turbocharger systems.
3Power
If the intake manifold pressure is increased to improve combustion, then the power output is improved, but the differential pressure between exhaust and intake manifolds decreases, limiting EGR supply
Solution Approach 1:
The patent introduces EGR blowers as intermediary devices to force exhaust gas recirculation. These blowers actively push EGR gas through the recirculation line regardless of the pressure differential between manifolds, enabling EGR supply across a wider range of operating conditions including high intake manifold pressure scenarios.
Solution Approach 2:
The patent changes the pressure parameter of the EGR supply system by using active EGR blowers instead of passive pressure differential-driven flow. This allows the EGR system to maintain effective recirculation across varying intake manifold pressures, expanding the operational range where EGR can be supplied.
4Object-generated harmful factors
If conventional EGR systems are used to reduce NOx emissions, then the emissions are improved, but the operation region for recirculating gas supply is limited
Solution Approach 1:
The patent introduces EGR blowers as intermediary devices to force exhaust gas recirculation. These blowers actively push EGR gas through the recirculation line regardless of the pressure differential between manifolds, enabling EGR supply across a wider range of operating conditions including high intake manifold pressure scenarios.
Solution Approach 2:
The patent makes the EGR system dynamic by using controllable EGR blowers that can adjust their operation based on driving conditions. This dynamic control allows the EGR system to adapt to varying engine operating regions, expanding the range where effective NOx reduction can be achieved.
5Quantity of substance
If high-pressure EGR device is used to supply recirculating gas, then the EGR rate is improved, but the differential pressure between manifolds must be high, limiting operation range
Solution Approach 1:
The patent introduces EGR blowers as intermediary devices to force exhaust gas recirculation. These blowers actively push EGR gas through the recirculation line regardless of the pressure differential between manifolds, enabling EGR supply across a wider range of operating conditions including high intake manifold pressure scenarios.
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 and expands the operation region for recirculating gas supply, improving vehicle performance and reducing emissions by optimizing air pressure and recirculation efficiency.
Implementation Method 1
an electric supercharger using a motor to drive a compressor to compress external air
Implementation Method 2
the EGR line is provided with an exhaust gas recirculation (EGR) cooler for cooling the recirculated exhaust gas
Implementation Method 3
a first intercooler disposed in the first intake line and configured for cooling the supercharged air
Data Source
AI summary
An engine system may include an engine including a plurality of intake lines through which outside air supplied to combustion chamber flows, a first electric supercharger and a second electric supercharger disposed respectively in the plurality of intake lines, a first exhaust gas recirculation (EGR) device including a first EGR line branched from an exhaust manifold and joining an intake manifold and a first EGR valve disposed in the first EGR line, and a controller determining an engine target torque according to a driving condition of the engine, setting an engine torque within an operation region of the first EGR device when the engine target torque is in a torque dead band between the operation region of the first EGR device and a non-operation region thereof, and compensating a difference value between the engine target torque and the engine torque by a hybrid electric vehicle (HEV) motor.