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Achieving controllable continuous variable damping within a semi-active hydro-pneumatic suspension system
Dissertation (MEng)--University of Pretoria, 2020.
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| Format: | Thesis |
| Language: | English |
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University of Pretoria
2021
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| _version_ | 1867613578912071680 |
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| access_status_str | Open Access |
| author2 | Els, P.S. (Pieter Schalk) |
| author_browse | Els, P.S. (Pieter Schalk) |
| author_facet | Els, P.S. (Pieter Schalk) |
| collection | Thesis |
| dc_rights_str_mv | © 2019 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. |
| description | Dissertation (MEng)--University of Pretoria, 2020. |
| format | Thesis |
| id | oai:repository.up.ac.za:2263/81135 |
| institution | University of Pretoria (South Africa) |
| language | English |
| last_indexed | 2026-06-10T12:38:22.689Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UPSpace — University of Pretoria Institutional Repository |
| publishDate | 2021 |
| publishDateRange | 2021 |
| publishDateSort | 2021 |
| publisher | University of Pretoria |
| publisherStr | University of Pretoria |
| record_format | dspace |
| source_str | UPSpace — University of Pretoria Institutional Repository |
| spelling | oai:repository.up.ac.za:2263/81135 Achieving controllable continuous variable damping within a semi-active hydro-pneumatic suspension system Els, P.S. (Pieter Schalk) u15334440@tuks.co.za De Wet, Benjamin Blow-off damping Continuous variable damping Hydro pneumatic suspension Physics based damping model 4S4 4S4-CVD UCTD Engineering, built environment and information technology theses SDG-09 SDG-09: Industry, innovation and infrastructure Engineering, built environment and information technology theses SDG-11 SDG-11: Sustainable cities and communities Engineering, built environment and information technology theses SDG-12 SDG-12: Responsible consumption and production Dissertation (MEng)--University of Pretoria, 2020. The compromise between ride comfort and handling for a passive suspension system is a well-known and often researched problem. Semi-active suspension systems offer significant improvements to this compromise. One example of a semi-active system, that can change both spring and damper characteristics between two discrete values is the 4-state semi-active hydro-pneumatic suspension system. This system can switch between a ”ride comfort mode” (soft spring and low damping) and a ”handling mode” (stiff spring and high damping) within 100ms, improving both ride comfort and handling. The discrete 4S4 could be improved upon further by adding continuous variable damping. Work on this topic showed great promise but also posed its challenges in achieving this in a safe and controllable manner. In order to make continuous variable damping a reality a new configuration for the 4S4 is proposed. This new configuration incorporates a blow-off damper in parallel with a proportional flow control valve. The system ensures that, in the highly non-linear closing region of the proportional flow control valve, adequate damping for handling is maintained and uncontrollable peak pressure differences are avoided. Experimental work conducted showed that the system was capable of achieving the required spring and variable damping characteristics in a safe and controllable manner. The experimental data was used for parametrizing and validating a physics based mathematical model of the suspension system. The mathematical model incorporates the: pressure drop vs: flow characteristics for both the blow-off and proportional valves, response time for the on-off valves as well as the gas pressure vs: flow characteristic incorporating the compressibility of the oil and thermal properties of the gas. This model can be used to make informed decisions on further prototype development or in full vehicle simulations. The system makes continuous variable damping possible ranging from the optimal damping characteristic for handling to the low damping characteristic required for ride comfort. The system also shows a significant reduction in friction. VDG University of Pretoria mi2025 Mechanical and Aeronautical Engineering MEng Unrestricted SDG-09: Industry, innovation and infrastructure SDG-11: Sustainable cities and communities SDG-12: Responsible consumption and production 2021-08-04T11:06:56Z 2021-08-04T11:06:56Z 2021-09 2020 Dissertation * S2021 http://hdl.handle.net/2263/81135 en © 2019 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. application/pdf University of Pretoria |
| spellingShingle | Blow-off damping Continuous variable damping Hydro pneumatic suspension Physics based damping model 4S4 4S4-CVD UCTD Engineering, built environment and information technology theses SDG-09 SDG-09: Industry, innovation and infrastructure Engineering, built environment and information technology theses SDG-11 SDG-11: Sustainable cities and communities Engineering, built environment and information technology theses SDG-12 SDG-12: Responsible consumption and production Achieving controllable continuous variable damping within a semi-active hydro-pneumatic suspension system |
| title | Achieving controllable continuous variable damping within a semi-active hydro-pneumatic suspension system |
| title_full | Achieving controllable continuous variable damping within a semi-active hydro-pneumatic suspension system |
| title_fullStr | Achieving controllable continuous variable damping within a semi-active hydro-pneumatic suspension system |
| title_full_unstemmed | Achieving controllable continuous variable damping within a semi-active hydro-pneumatic suspension system |
| title_short | Achieving controllable continuous variable damping within a semi-active hydro-pneumatic suspension system |
| title_sort | achieving controllable continuous variable damping within a semi active hydro pneumatic suspension system |
| topic | Blow-off damping Continuous variable damping Hydro pneumatic suspension Physics based damping model 4S4 4S4-CVD UCTD Engineering, built environment and information technology theses SDG-09 SDG-09: Industry, innovation and infrastructure Engineering, built environment and information technology theses SDG-11 SDG-11: Sustainable cities and communities Engineering, built environment and information technology theses SDG-12 SDG-12: Responsible consumption and production |
| url | http://hdl.handle.net/2263/81135 |