Exhaust Valve Flap Load Sensing for Harsh-Environment Flow Control
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Solution Overview
Problem
Pressure sensors in exhaust systems of internal combustion engines are exposed to high pressures and thermal loads, necessitating stringent requirements and potentially unreliable measurements for controlling exhaust gas flow.
Innovation Solution
An exhaust system with a valve flap and actuator that controls gas flow via load detection, using an actuator load sensor to measure the actuator's load magnitude instead of pressure, allowing for alternative and more reliable control of the valve flap position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a pressure sensor is used to measure pressure in the exhaust conduit, then pressure information can be obtained for control purposes, but the pressure sensor is exposed to high pressures and thermal loads resulting in strict requirements and potentially unreliable measurements
Solution Approach 1:
The patent introduces an actuator as an intermediary device that indirectly measures exhaust pressure by detecting the load required to move the valve flap. Instead of placing a pressure sensor directly in the harsh exhaust environment, the actuator measures mechanical load (via current, voltage, or torque) which correlates to the pressure differential across the valve. This mediator approach transfers the measurement function from a pressure sensor exposed to thermal/pressure loads to an actuator operating in benign electrical/mechanical conditions.
Solution Approach 2:
The patent replaces the mechanical pressure sensing approach with an electrical/mechanical actuator-based measurement system. Rather than using a pressure sensor that directly detects gas pressure, the system uses an actuator whose electrical characteristics (current, voltage, power) or mechanical characteristics (torque, force) change in response to the load imposed by exhaust pressure on the valve flap. This substitution moves the measurement from a direct mechanical pressure interface to an electrical signal that can be measured without exposure to harsh conditions.
2Ease of operation
If a pressure sensor is placed in the exhaust conduit to detect pressure conditions, then exhaust gas flow control can be achieved, but the sensor and connection must withstand high pressures and thermal loads
Solution Approach 1:
The actuator serves as an intermediary between the control system and the exhaust gas flow. By measuring the electrical or mechanical characteristics of the actuator (which is located outside or at the boundary of the exhaust conduit), the system indirectly obtains information about exhaust pressure and flow conditions without exposing sensitive measurement components to thermal and pressure hazards.
Solution Approach 2:
The measurement function is extracted from the harsh exhaust environment and placed in a benign location. The actuator and its sensing elements are positioned outside the high-temperature, high-pressure exhaust conduit, eliminating direct exposure to harmful factors while maintaining the ability to control exhaust flow through the valve mechanism.
3Extent of automation
If an actuator is used to control the valve flap position, then exhaust gas flow can be controlled, but the actuator must withstand the load from exhaust pressure differential
Solution Approach 1:
The patent implements feedback by using the actuator's load characteristics (electrical current, voltage, or mechanical torque) as a measure of the force it is experiencing against the exhaust pressure differential. This feedback information allows the control system to understand both the commanded valve position and the actual opposing force, enabling adaptive control that accounts for varying exhaust conditions without requiring additional force sensors in the high-pressure environment.
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
Provides a more robust and efficient method to control exhaust gas flow by measuring actuator load, reducing the need for pressure sensors in harsh environments and enhancing control accuracy.
Implementation Method 1
an actuator load sensor adapted to detect load information indicative of a magnitude of the load that the actuator currently imparts on at least the portion of the valve
Data Source
AI summary
The present disclosure relates to an exhaust system for an internal combustion engine. The exhaust system comprises an exhaust conduit adapted to fluidly connect the internal combustion engine to a turbine of a turbo and a valve comprising a valve flap located in the exhaust conduit in a position between the internal combustion engine and the turbine. The valve flap is pivotally connected to at least a portion of the exhaust conduit. The exhaust system further comprises an actuator adapted to impart a load on at least a portion of the valve to thereby control a pivotal position of the valve flap in the exhaust conduit to thereby control a gas flow via the exhaust conduit and an actuator load sensor adapted to detect load information indicative of a magnitude of the load that the actuator currently imparts on at least the portion of the valve.