Variable Inlet Compressor Actuator Diagnostics via Back-EMF
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Solution Overview
Problem
Variable inlet compressors in turbochargers can suffer from degradation due to stuck actuators, leading to reduced engine performance and potential damage, as existing diagnostic methods are either invasive or costly, and there is a need for reliable and timely diagnosis to prevent turbocharger degradation.
Innovation Solution
A method using the electrical power usage of an electric boost assist motor to diagnose actuator degradation in a variable inlet compressor by measuring back-EMF and comparing it to expected compressor speed and pressure ratios, allowing for timely servicing without dedicated sensors, leveraging existing components for reliable diagnosis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the actuator is commanded open during high mass flow operation, then the maximum pressure capability of the boosted engine system is improved, but if the variable inlet compressor is stuck closed, the compressor wheel speed increases causing potential degradation and damage
Solution Approach 1:
The system continuously monitors electrical power consumption of the electric boost assist motor and compares it against expected values for given operating conditions. When the actual power consumption deviates from expected values, the system detects actuator degradation and adjusts operation to prevent compressor damage while maintaining acceptable performance.
2Reliability
If existing diagnostic methods are used to detect actuator degradation, then reliability improvement is achieved, but the methods are either invasive or costly
Solution Approach 1:
The electric boost assist motor serves dual purposes: providing boost assistance and enabling self-diagnosis of the variable inlet compressor actuator. The motor's existing electrical characteristics (power consumption, back-EMF) are utilized as diagnostic signals, eliminating the need for separate diagnostic sensors or invasive measurement systems.
Solution Approach 2:
The electric boost assist motor performs multiple functions: it provides mechanical assistance to the compressor during transient conditions and simultaneously serves as a diagnostic sensor for detecting actuator degradation through its electrical characteristics, reducing the need for additional dedicated components.
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
This approach enables reliable and cost-effective diagnosis of variable inlet compressor degradation, preventing turbocharger damage and improving engine performance by identifying issues before they cause significant harm.
Implementation Method 1
measuring back-EMF and comparing it to expected compressor speed and pressure ratios
Data Source
AI summary
Methods and systems are provided for diagnosing an actuator of a variable inlet compressor coupled in an electric turbocharger. During torque transitions, an electrical power consumption of an electric boost assist motor is observed and used to infer an actual compressor speed and pressure ratio across the compressor. By comparing the measured pressure ratio to a compressor map, it may be determined if the actuator is stuck open or stuck closed.