EGR Mixer Jet Pump Venturi Nozzle Pressure Differential
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Solution Overview
Problem
Existing exhaust gas recirculation (EGR) systems face challenges in delivering cooled EGR from the exhaust manifold to the intake manifold without negatively impacting engine efficiency and knock tendency, especially in high-load and high-boost conditions.
Innovation Solution
The implementation of an exhaust gas recirculation mixer that uses a jet pump mechanism to create a pressure differential, allowing exhaust gas to be recirculated into a pressurized engine intake even when the exhaust gas source is at a lower pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the classic high pressure loop cEGR system plumbs exhaust gas directly to the intake manifold, then EGR delivery is achieved, but engine efficiency is reduced due to negative pressure work and residual gas retention
Solution Approach 1:
A low-pressure receiver chamber is introduced as an intermediary between the exhaust manifold and intake manifold. The jet pump creates a pressure differential that draws EGR through this intermediate chamber, allowing controlled delivery without directly imposing negative pressure on the engine cylinders, thereby reducing residual gas retention and improving efficiency
Solution Approach 2:
The patent replaces the classic mechanical high-pressure loop EGR system with a jet pump-based system that uses fluid dynamics (venturi effect) to create pressure differentials. This substitution eliminates the need for mechanical compressors or turbochargers to force EGR delivery, reducing mechanical losses and improving overall system efficiency
2Quantity of substance
If design or variable turbocharging is used to force exhaust manifold pressure higher than intake manifold pressure, then EGR delivery is enabled, but scavenging of hot burned gases is reduced
Solution Approach 1:
Instead of forcing exhaust pressure higher than intake pressure (classic approach), the patent inverts the approach by using the jet pump to create a temporary low-pressure zone in the receiver chamber during EGR delivery. This allows EGR to be drawn from the exhaust manifold without requiring sustained high exhaust pressure, thereby preserving natural scavenging of hot burned gases
3Object-affected harmful factors
If cooled EGR is delivered from exhaust manifold to intake manifold under high-load and high-boost conditions, then knock tendency is reduced, but system efficiency is lost due to pressure differential requirements
Solution Approach 1:
The jet pump system is self-regulating based on engine operating conditions. During high-load and high-boost conditions, the system automatically creates the necessary pressure differential to deliver cooled EGR when needed to reduce knock tendency, without requiring external mechanical assistance. The system uses the engine's own intake airflow to drive the jet pump, converting available kinetic energy into useful EGR delivery
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 solution mitigates system efficiency losses and reduces knock tendency by enabling effective EGR delivery across varying pressure ratios, improving engine efficiency and power density.
Implementation Method 1
a venturi nozzle in a flow path from the air inlet to the outlet of the mixer. The venturi nozzle increases a velocity and decreases a pressure of an air flow
Implementation Method 2
The venturi nozzle increases a velocity and decreases a pressure of an air flow
Data Source
Figure 1
Figure 2
AI summary
An exhaust gas recirculation mixer includes a convergent nozzle in a flow path from an air inlet of the mixer to an outlet of the mixer. The convergent nozzle is oriented converging toward the outlet of the mixer. The nozzle accelerates the flow to high velocity, which is released as a free-jet. The mixer includes an exhaust gas housing having an exhaust gas inlet into an interior of the exhaust gas housing, and a convergent-divergent nozzle having an air-fuel-exhaust gas inlet in fluid communication to receive fluid flow from the convergent nozzle (i.e., the free-jet), the interior of the exhaust gas housing, and a fuel supply into the mixer.