Virtual Turbine Speed Sensor for Multi-Stage Turbocharger
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Solution Overview
Problem
Conventional sequential multiple-stage turbocharger systems rely on expensive physical turbine speed sensors, which are difficult to integrate into on-board diagnostic systems, necessitating the development of virtual turbine speed sensors for accurate speed estimation.
Innovation Solution
A virtual turbine speed sensor system comprising a compressor efficiency module, inter-stage air temperature module, and turbine speed module, which estimates compressor efficiency, inter-stage temperature, and turbine speed using sensed parameters and look-up tables, allowing for the prediction of turbine speeds without physical sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If physical turbine speed sensors are used to monitor turbine speeds, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent creates a virtual copy of the physical speed sensor functionality by using software algorithms and available sensor data (manifold pressure, temperature, mass flow rate) to calculate and estimate turbine speed. This virtual sensor copy eliminates the need for expensive physical speed sensors while maintaining the diagnostic capability.
Solution Approach 2:
The patent replaces the mechanical/physical speed sensor system with an electronic/software-based calculation system. Instead of using physical contact sensors to directly measure turbine rotation, the system uses mathematical models and electronic sensor data to compute turbine speed, thereby reducing hardware complexity.
2Reliability
If physical turbine speed sensors are installed on each turbine, then reliability of speed monitoring is improved, but ease of manufacture and installation deteriorates
Solution Approach 1:
The patent makes the existing sensor system (manifold pressure sensors, temperature sensors, mass flow sensors) multi-functional by using it not only for its original purposes but also for calculating turbine speed. This universal approach eliminates the need for dedicated speed sensors and simplifies manufacturing and installation.
Solution Approach 2:
The system uses its own existing sensor infrastructure and processing capabilities to generate turbine speed information without requiring external or additional specialized components. The control module that already exists for other functions is repurposed to also perform speed estimation.
3Device complexity
If virtual turbine speed sensors are implemented, then device complexity is reduced, but measurement precision may deteriorate
Solution Approach 1:
The patent implements feedback mechanisms where the estimated turbine speed is continuously calculated and can be used to validate the model assumptions. The system monitors the consistency of calculated speeds with expected operational ranges and can adjust or flag anomalies, maintaining precision through continuous validation.
Solution Approach 2:
The patent uses multiple different parameters (manifold absolute pressure, inter-stage pressure, air mass flow rate, temperature) to calculate turbine speed through different relationships and formulas. By changing and comparing multiple parameter-based calculations, the system improves estimation accuracy while keeping the device simple.
Data Source
AI summary
According to one exemplary embodiment, a virtual turbine speed sensor for a multi-stage turbocharger system of an internal combustion engine is disclosed. The multi-stage turbocharger system includes at least two sequential turbochargers each having a compressor and a turbine. The virtual turbine speed sensor includes a compressor efficiency module, an inter-stage air temperature module, and a turbine speed module. The compressor efficiency module is configured to estimate an efficiency of a compressor of a first of the at least two turbochargers. The inter-stage air temperature module is configured to estimate an inter-stage temperature of air between the at least two compressors. The inter-stage temperature estimate is based at least partially on the efficiency of the compressor of the first turbocharger. The turbine speed module is configured to estimate a speed of a turbine of a second of the at least two turbochargers. The speed estimate of the turbine of the second turbocharger is based at least partially on the temperature estimate of air between the at least two compressors.