Staged Boost Control for Turbocharger Temperature Management
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Solution Overview
Problem
Multi-staged turbocharged engine systems face issues with component temperature control, particularly the turbocharger compressor, which can exceed critical temperatures under high load or high altitude conditions, leading to potential hardware failure and degraded vehicle performance.
Innovation Solution
Implementing a method that bypasses the second compressor and uses an electric supercharger to share the boost load with the turbocharger, reducing the turbocharger compressor's outlet temperature without degrading engine performance by adjusting the power ratio between the electric motor and engine crankshaft.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the turbocharger compressor operates at high boost pressure under high load conditions, then engine power output is improved, but the compressor outlet temperature exceeds critical temperature leading to hardware failure risk
Solution Approach 1:
A charge air recirculation system is introduced as an intermediary component between the turbocharger compressor outlet and inlet. This recirculation path allows a portion of the compressed air to be redirected back to the compressor inlet, effectively reducing the compressor outlet temperature by lowering the compression ratio and mass flow through the compressor, while maintaining the required boost pressure for engine power output.
2Temperature
If the compressor recirculation valve is opened to reduce compressor outlet temperature, then temperature control is improved, but the boost pressure drops below driver demanded boost pressure resulting in torque under-delivery
Solution Approach 1:
A closed-loop feedback control system is implemented where the compressor outlet temperature and boost pressure are continuously monitored by sensors. The controller dynamically adjusts the recirculation valve position based on temperature feedback while simultaneously adjusting the wastegate position to maintain the target boost pressure. This dual-feedback mechanism ensures temperature control is achieved without sacrificing the driver-demanded boost pressure and torque delivery.
3Productivity
If the turbocharger is operated at high boost pressure to meet driver torque demand, then vehicle performance is improved, but the turbocharger integrity is compromised beyond 10 seconds of operation above 400K compressor outlet temperature
Solution Approach 1:
The control system performs preliminary action by proactively monitoring compressor outlet temperature and predicting when temperature limits will be exceeded. Before the turbocharger integrity is compromised, the controller preemptively activates the charge air recirculation system and adjusts the wastegate to reduce compressor load and temperature. This preventive approach allows the system to maintain high boost pressure and vehicle performance while ensuring the turbocharger operates within safe temperature limits, preventing hardware failure.
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 effectively controls turbocharger compressor temperature without reducing boost pressure, extending component life and maintaining vehicle driveability and performance.
Implementation Method 1
accelerating a second, downstream compressor to reduce the load, and thereby the temperature, of an upstream, first compressor
Implementation Method 2
bypassing the first compressor and providing a flow of compressed air to an engine via a second compressor; in response to an outlet temperature of the first compressor being at or above a threshold, accelerating the second compressor
Data Source
AI summary
Methods and systems are provided for turbine temperature control in an engine system having multiple staged charge boosting devices. In one example, compressed air is provided by a turbocharger compressor until an outlet temperature of the compressor reaches a limit. Thereafter, a compressor of a downstream supercharger is operated to share the load