Pressure Ratio Influence on Exhaust Valve Flow Coefficients

In one dimensional engine simulation software, flow losses over complex geometries such as valves and ports are described using flow coefficients. It is generally assumed that the pressure ratio over the valve has a negligible influence on the flow coefficient. However during the exhaust valve opening the pressure difference between cylinder and port is large which questions the accuracy of this assumption. In this work the influence of pressure ratio on the exhaust valve flow coefficient has been investigated experimentally in a steady-flow test bench. Two cylinder heads, designated A and B, from a Heavy-Duty engine with different valve shapes and valve seat angles have been investigated. The tests were performed with both exhaust valves open and with only one of the two exhaust valves open. The pressure ratio over the exhaust port was varied from 1.1:1 to 5:1. For case A1 with a single exhaust valve open, the flow coefficient decreased significantly with pressure ratio. This trend was not replicated for the other single valve case B1, as pressure ratio only had a small influence on the flow coefficient. For the twin valve case A2, the pressure ratio influence was confined to the lower range of valve lifts as the limiting factor was the exhaust port outlet at higher valve lifts. The flow coefficient for the twin valve case B2 increased with pressure ratio in the mid-range of valve lifts.

• Record URL:
  https://doi.org/10.4271/2017-01-0530
• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/issn/01487191
• Supplemental Notes:
  • Abstract reprinted with permission of SAE International.
• Authors:
  • Holmberg, Ted
  • Cronhjort, Andreas
  • Stenlaas, Ola
• 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;
• 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: Coefficients; Compression; Exhaust valves; Flow; Pressure; Ratios
• Subject Areas: Energy; Highways; Vehicles and Equipment;

Filing Info

• Accession Number: 01650831
• Record Type: Publication
• Source Agency: SAE International
• Report/Paper Numbers: 2017-01-0530
• Files: TRIS, SAE
• Created Date: Nov 15 2017 11:30AM