Single EGR Valve with Multiple Flow Paths for Turbocharged Engine
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Solution Overview
Problem
Existing EGR systems for internal combustion engines with two separate EGR valves and coolers face challenges in controlling EGR rate and engine torque stability due to differing flow characteristics and require complex temperature-dependent operations, leading to inefficient EGR flow and increased system complexity.
Innovation Solution
A system utilizing a single EGR valve with multiple flow paths that directs exhaust gases either upstream or downstream of the turbocharger compressor, controlled by a controller that compensates for state changes to maintain consistent EGR flow and reduce engine torque fluctuations, eliminating the need for multiple EGR coolers and simplifying control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If two separate EGR valves are used to provide EGR upstream and downstream of the compressor, then large amounts of EGR can be provided at high engine speed and load, but the system complexity increases and control difficulty arises due to different flow characteristics of the two valves
Solution Approach 1:
The patent combines two separate EGR valves into a single EGR valve with multiple flow paths. The single valve body includes a first flow path leading to the compressor inlet and a second flow path leading to the compressor outlet, eliminating the need for two separate valves and their associated coolers. This merging reduces system complexity while maintaining the capability to provide large amounts of EGR at high engine speed and load.
Solution Approach 2:
The single EGR valve is designed with multi-functionality to perform the roles of two separate valves. It can direct exhaust gases through different flow paths (upstream or downstream of the compressor) depending on operating conditions, providing universal EGR delivery capability across various engine operating ranges without requiring multiple specialized components.
2Adaptability or versatility
If two separate EGR valves are simultaneously controlled, then EGR can be delivered to both upstream and downstream locations, but torque stability decreases due to difficulty in controlling two valves with different flow characteristics
Solution Approach 1:
By merging two separate EGR valves into one single valve with multiple flow paths, the system eliminates the control difficulties associated with coordinating two independently controlled valves. The single valve provides stable and repeatable EGR delivery to either the upstream or downstream location, improving torque stability while maintaining adaptability through the controller's ability to select appropriate flow paths based on engine operating conditions.
3Object-affected harmful factors
If EGR flow path switching is implemented based on temperature sensor readings, then particulate filter regeneration can be enabled, but EGR flow may be inhibited during low temperature operation even when desired EGR flow rate is needed
Solution Approach 1:
The system dynamically switches between different EGR flow paths based on real-time operating conditions. The controller monitors engine parameters and exhaust temperatures, and automatically directs EGR through the appropriate path (upstream or downstream of the compressor) to maintain desired EGR flow rates while protecting the particulate filter during regeneration events, avoiding the inhibition of EGR flow that occurs with fixed temperature-based control.
Data Source
AI summary
A system and method for delivering EGR to an internal combustion engine is presented. The system can reduce system cost and lower system complexity.