Differential Pressure Valve Boost Inlet Optimization
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Solution Overview
Problem
Conventional low pressure exhaust gas recirculation (LPEGR) systems face challenges in accurately controlling boost device inlet pressure, leading to insufficient EGR operation at low engine loads and increased noise/vibration/harshness (NVH), affecting engine efficiency and other related systems.
Innovation Solution
A control system with a differential pressure (dP) valve and a controller that determines and adjusts the boost device inlet pressure to balance competing targets and hardware limits across multiple systems, using a primary open-loop and secondary closed-loop control scheme to optimize engine performance and prevent component damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional LPEGR systems control boost device inlet pressure, then EGR operation is enabled, but insufficient EGR operation occurs at low engine load conditions and NVH increases
Solution Approach 1:
The system dynamically adjusts the dP valve position based on real-time operating conditions (engine load, speed, temperature) to optimize boost device inlet pressure. The control system transitions from static pressure control to dynamic adaptation, allowing the EGR system to maintain reliable operation across varying engine loads while minimizing NVH by adjusting valve position according to current operational demands.
Solution Approach 2:
The invention changes the control parameter from simple EGR flow rate to boost device inlet pressure as the primary controlled variable. By using the dP valve to directly control inlet pressure rather than relying solely on EGR valve positioning, the system achieves more precise pressure regulation that simultaneously improves EGR operation reliability and reduces NVH through optimized pressure management.
2Productivity
If boost device inlet pressure is increased to improve EGR operation, then EGR flow is enhanced, but hardware limits of components may be exceeded causing potential damage
Solution Approach 1:
The control system continuously monitors boost device inlet pressure and compares it against hardware limits, using feedback to adjust the dP valve position. When pressure approaches component safety thresholds, the system automatically reduces valve opening to maintain pressure within safe operating ranges, thereby protecting components while still maximizing EGR flow under normal conditions.
Solution Approach 2:
The system establishes predetermined safety margins and pressure thresholds before operation, creating a protective buffer against component damage. By programming hardware limits and surge margins into the control logic in advance, the system prevents pressure from reaching dangerous levels that could damage the compressor or other components, while still allowing optimal EGR flow within safe boundaries.
3Measurement precision
If dP valve is used to control boost device inlet pressure, then pressure control precision is improved, but system complexity increases
Solution Approach 1:
The dP valve serves multiple functions: it controls boost device inlet pressure, prevents compressor surge, protects against hardware limits, and optimizes EGR flow. By making this single component multi-functional, the system achieves precise pressure control without proportionally increasing overall system complexity, as the same valve and control logic handle multiple protective and performance functions.
Solution Approach 2:
The dP valve acts as an intermediary component between the atmosphere and the boost device, providing precise pressure control at the inlet. This intermediate control point allows the system to regulate pressure before it enters the compressor, enabling fine-tuned control without requiring complex modifications to the compressor itself or other major system components.
Data Source
AI summary
Techniques for controlling a forced-induction engine having a low pressure cooled exhaust gas recirculation (LPCEGR) system comprise determining a target boost device inlet pressure for each of one or more systems that could require a boost device inlet pressure change as part of their operation and boost device inlet pressure hardware limits for a set of components in the induction system, determining a final target boost device inlet pressure based on the determined sets of target boost device inlet pressures and boost device inlet pressure hardware limits, and controlling a differential pressure (dP) valve based on the final target boost device inlet pressure to balance (i) competing boost device inlet pressure targets of the one or more systems and (ii) the set of boost device inlet pressure hardware limits in order to optimize engine performance and prevent component damage.