Electric Motor Assisted Variable Geometry Turbocharger Control
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Solution Overview
Problem
Internal combustion engine air handling systems face challenges in responding effectively to transient operating conditions, particularly in providing responsive air handling during such events.
Innovation Solution
An air handling system incorporating a turbocharger with a variable geometry turbine and an electric motor-assisted rotatable shaft, where a control circuit determines and adjusts the target torque required to drive the compressor, enabling the electric motor to supply supplemental torque when necessary, and controls the turbine geometry to optimize brake specific fuel consumption or fuel economy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional turbocharger system is used without electric motor assistance, then the system structure remains simple, but the system cannot respond effectively to transient operating conditions
Solution Approach 1:
The patent combines a conventional turbocharger system with an electric motor assistance system. The electric motor is coupled to the rotatable shaft to provide supplemental torque during transient conditions, merging two different power sources (exhaust gas-driven turbine and electric motor) into a hybrid air handling system that leverages the strengths of both.
Solution Approach 2:
The patent implements dynamic control of the variable geometry turbine (VGT) system where the turbine geometry can be adjusted in real-time based on operating conditions. The control circuit dynamically determines when electric motor assistance is needed and adjusts the VGT geometry to optimize torque distribution between the turbine and electric motor, enabling adaptive response to transient conditions.
2Reliability
If the electric motor supplies supplemental torque during all operating conditions, then the compressor can always meet target operating parameters, but energy consumption increases
Solution Approach 1:
The control circuit continuously monitors compressor operating parameters and compares them against target values. Based on this feedback, the control circuit determines when the turbine can meet torque requirements independently and when electric motor assistance is needed. The system only activates the electric motor when the determined available turbine torque is insufficient to meet the determined target torque, optimizing energy usage.
Solution Approach 2:
The system dynamically changes operational parameters including the geometry of the variable geometry turbine and the enable/disable state of the electric motor. By adjusting these parameters based on real-time conditions, the system optimizes the balance between turbine-generated torque and electric motor supplemental torque, ensuring reliable compressor operation while minimizing energy consumption.
3Use of energy by moving object
If the variable geometry turbine is controlled to optimize fuel economy, then brake specific fuel consumption improves, but exhaust gas flow management may be compromised
Solution Approach 1:
The variable geometry turbine allows dynamic adjustment of exhaust gas flow paths and turbine wheel geometry. The control circuit can optimize the VGT geometry for fuel economy by controlling the guide vane angles and exhaust gas routing, while the electric motor assistance ensures that sufficient torque is still delivered to the compressor to maintain proper exhaust gas flow rates, preventing compromise of exhaust management.
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 ensures responsive air handling during transient conditions by providing supplemental torque and adjusting turbine geometry, thereby improving fuel efficiency and exhaust gas flow management.
Implementation Method 1
an electric motor coupled to the rotatable shaft, the electric motor supplying supplemental torque to the rotatable shaft when enabled for operation
Implementation Method 2
the variable geometry turbine rotatably drives the compressor via the rotatable shaft in response to exhaust gas passing through the variable geometry turbine
Data Source
AI summary
A system and method are provided for controlling an air handling system for an internal combustion engine including a turbocharger having a variable geometry turbine fluidly coupled to an exhaust manifold of the engine and a compressor fluidly coupled to an intake manifold of the engine, and an electric motor coupled to a rotatable shaft connected between the compressor and the variable geometry turbine. A target torque required to drive the compressor to achieve target compressor operating parameters is determined, a maximum available torque that can be supplied by the variable geometry turbine in response to a target exhaust gas flow through the variable geometry turbine is determined, and the electric motor is enabled to supply supplemental torque to the rotatable shaft if the target torque is greater than the maximum available torque.