Investigation of Performance Differences and Control Synthesis for Servo-Controlled and Vacuum-Actuated Wastegates
Turbocharging plays an important role in the downsizing of engines. Model-based approaches for boost control are increasing the necessity for controlling the wastegate flow more accurately. In today’s cars, the wastegate is usually only controlled with a duty cycle and without position feedback. Due to nonlinearities and varying disturbances a duty cycle does not correspond to a certain position. Currently the most frequently used feedback controller strategy is to use the boost pressure as the controller reference. This means that there is a large time constant from actuation command to effect in boost pressure, which can impair dynamic performance. In this paper, the performance of an electrically controlled vacuum-actuated waste-gate, subsequently referred to as vacuum wastegate, is compared to an electrical servo-controlled wastegate, also referred to as electric wastegate. Their performance is investigated with the two actuators installed on a turbocharged inline four gasoline engine in an engine test bench. Furthermore, different control synthesis designs for these different actuators are investigated. A state-feedback controller with standard models for the electric wastegate is described and implemented, which gives a position-controlled wastegate. One main difference between vacuum and electric wastegate is that the latter has a position sensor. To make an extended comparison between the solutions, the vacuum wastegate is also equipped with a position sensor and controller using standard controller design methods. The controllers are implemented and compared both in a simulation environment and evaluated in an engine test bench. In addition, for the electric wastegate, both soft-landing and tightening features are also implemented and investigated. Their aim is to improve the lifetime and behavior at or near the closed position.
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Availability:
- Find a library where document is available. Order URL: http://worldcat.org/issn/01487191
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Supplemental Notes:
- Abstract reprinted with permission of SAE International.
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Authors:
- Holmbom, Robin
- Liang, Bohan
- Eriksson, Lars
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Conference:
- WCX™ 17: SAE World Congress Experience
- Location: Detroit Michigan, United States
- Date: 2017-4-4 to 2017-4-6
- Publication Date: 2017-3-28
Language
- English
Media Info
- Media Type: Web
- Features: Figures; References;
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Serial:
- SAE Technical Paper
- Publisher: Society of Automotive Engineers (SAE)
- ISSN: 0148-7191
- EISSN: 2688-3627
- Serial URL: http://papers.sae.org/
Subject/Index Terms
- TRT Terms: Emission control systems; Exhaust valves; Servomechanisms; Turbochargers; Vacuum measurement
- Subject Areas: Energy; Highways; Vehicles and Equipment;
Filing Info
- Accession Number: 01657758
- Record Type: Publication
- Source Agency: SAE International
- Report/Paper Numbers: 2017-01-0592
- Files: TRIS, SAE
- Created Date: Jan 25 2018 9:31AM