Low Temperature Combustion Exploration with Negative Valve Overlap

2022-01-0452

03/29/2022

Features
Event
WCX SAE World Congress Experience
Authors Abstract
Content
Progressively stringent emission regulations and increasing regulatory demands on fuel economy have led to advanced combustion development. Low temperature combustion (LTC), specifically homogenous charge compression ignition (HCCI), is a promising technology for reducing exhaust emissions and improving efficiency. However, its operating range is limited to low load without boosting and EGR, due to low volumetric efficiency and high pressure rise rates. In addition, effectively controlling the combustion phasing is another challenge in realizing the associated combustion gains.
In this work, advanced valve control mechanisms known as continuously variable valve duration (CVVD) and continuously variable valve timing (CVVT) were used for both intake and exhaust valvetrains to enable negative valve overlap (NVO) for trapping hot exhaust residuals and to promote multipoint simultaneous ignition. Heat release phasing was controlled by varying the fueling scheme and by adjusting the amount of NVO. Parametric studies on valve timing and duration, fueling strategy, lambda, spark assist, etc., were carried out first. Afterwards the LTC strategy was proposed and then LTC operation was explored at different engine speeds. Various approaches for extending load limits were summarized and discussed. Finally, combustion performance was compared to that of spark ignition combustion, demonstrating the combustion gains of LTC.
Meta TagsDetails
DOI
https://doi.org/10.4271/2022-01-0452
Pages
8
Citation
Zhu, S., Joo, N., Hollowell, J., Ha, K. et al., "Low Temperature Combustion Exploration with Negative Valve Overlap," SAE Technical Paper 2022-01-0452, 2022, https://doi.org/10.4271/2022-01-0452.
Additional Details
Publisher
Published
Mar 29, 2022
Product Code
2022-01-0452
Content Type
Technical Paper
Language
English