LPEGR Control System Using Modeled Pressures
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Solution Overview
Problem
Turbocharged gasoline engines with low pressure exhaust gas recirculation (LPEGR) systems face challenges in accurate control and estimation due to high sensitivity to minor pressure fluctuations, noise/vibration/harshness issues, and the need for precise air/fuel ratio control, which is difficult to achieve with conventional systems that require multiple sensors and are not adaptable to changing conditions.
Innovation Solution
A control system that includes a differential pressure (dP) valve and a controller that determines target positions for the EGR and dP valves based on modeled pressures, using minimal sensors (three pressure sensors and one exhaust gas concentration sensor) to maintain accurate EGR mass flow and mitigate noise, while adapting to long-term changes in engine conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional LPEGR control systems are used with multiple sensors to achieve accurate control, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent replaces multiple physical sensors with a computational model that uses minimal sensor inputs (three pressure sensors and one exhaust gas concentration sensor) to calculate EGR mass flow and other critical parameters. The controller implements a mathematical model that substitutes for the mechanical sensing system, achieving accurate measurements without requiring extensive sensor arrays.
Solution Approach 2:
The patent creates a virtual copy of the physical system through mathematical modeling. Instead of directly measuring all parameters with sensors, the system creates computational representations (modeled pressures, estimated mass flows) that mirror the physical state, allowing accurate control with fewer physical sensors.
2Productivity
If precise control of EGR flow is implemented to improve engine performance, then fuel efficiency is improved, but sensitivity to pressure fluctuations increases control difficulty
Solution Approach 1:
The patent implements a feedback control system where the controller continuously monitors measured pressures and exhaust gas concentration, compares them against modeled values, and adjusts valve positions accordingly. The system uses feedback loops that account for pressure fluctuations by continuously updating the mathematical model based on actual sensor readings, maintaining stable control despite environmental variations.
Solution Approach 2:
The patent dynamically adjusts control parameters based on operating conditions. The mathematical model adapts to changing pressure conditions by using real-time sensor data to update calculated parameters, allowing the system to maintain optimal EGR flow control across varying engine loads and environmental conditions without being overly sensitive to transient fluctuations.
3Adaptability or versatility
If adaptive control is implemented to handle changing engine conditions, then adaptability is improved, but device complexity increases
Solution Approach 1:
The patent implements a self-adapting control system where the mathematical model automatically adjusts to changing conditions using sensor feedback. The controller performs self-calibration and parameter updates without requiring external intervention or complex adaptive algorithms, allowing the system to adapt to varying engine conditions through its inherent computational framework.
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
The system achieves precise control of EGR flow, reduces noise and vibration, and improves fuel efficiency by accurately tracking exhaust gas constituents and adapting to changing engine conditions, thereby enhancing engine performance and reducing the risk of hardware failure.
Implementation Method 1
an EGR valve disposed in a low pressure EGR (LPEGR) system of the engine and configured to control a flow of exhaust gas produced by the engine from an exhaust system of the engine at a first point downstream from a turbine of the turbocharger to an induction system of the engine at a second point upstream from a compressor of the turbocharger
Implementation Method 2
a differential pressure (dP) valve disposed in the induction system of the engine at a third point upstream from the second point and configured to control a flow of air through the induction system
Implementation Method 3
The kinetic energy of the exhaust gas drives a turbine of the turbocharger, which in turn drives the compressor
Implementation Method 4
A turbocharged engine utilizes a compressor of a turbocharger to force air through an induction system and a throttle valve and into an intake manifold
Data Source
AI summary
Systems and methods for a turbocharged gasoline engine utilize a controller configured to receive a set of parameters including a measured pressure delta across an exhaust gas recirculation (EGR) valve disposed in a low pressure EGR (LPEGR) system of the engine and a measured pressure at an outlet of a differential pressure (dP) valve disposed in and distinct from a throttle valve of an induction system of the engine. The controller is further configured to determine a set of modeled pressures based on the set of parameters, a target EGR valve mass flow, a target EGR valve delta pressure, a current dP valve mass flow, and a pressure at an outlet of the air filter, determine target positions for the EGR valve and the dP valve based on the set of modeled pressures, and control the EGR valve and the dP valve based on their respective target positions.