A Late Injection Combustion Strategy Using a Novel Ramped Combustion System

Paper #:
  • 2017-24-0090

  • 2017-09-04
Urban air quality remains a major concern, in particular NOx and particle emission from diesel powered vehicles. Electrification offers a medium to long term solution, but there remains a need to significantly reduce internal combustion engine emissions in the short and medium term and potentially in the long term for long range inter city transportation. Late injection low temperature combustion (LTC) has the potential to achieve ultra-low emissions levels in a compression ignition engine by increasing the lean pre-mixed burn fraction. However, significant quantities of diluent are normally required to achieve the required delay in ignition and pre-mixing. This results in high boost requirements and increased pumping work negating the benefit of the LTC combustion strategy and increasing fuel consumption. Test results from a single cylinder light duty research engine are presented using a novel ramped combustion chamber. The ramped combustion chamber improves mixing and enables more retarded injection timings than those possible on conventional bowl designs. This combustion strategy has enabled LTC conditions to be achieved at lower dilution rates, typically 20-30% at loads up to 15bar IMEP. Data at a range of loads including trade-offs with key parameters will be presented. Analysis of the relationship between the ignition delay required to achieve LTC and the heat release characteristics is presented. CFD analysis of the ramped and a conventional bowl was then used to aid interpretation of the results and is compared with the Sandia conceptual model for late injection LTC. The paper concludes with a study using 1D air system analysis to investigate the benefit of applying a Miller valve timing strategy to improve the fuel consumption of the engine with a late injection strategy.
SAE MOBILUS Subscriber? You may already have access.
Attention: This item is not yet published. Pre-Order to be notified, via email, when it becomes available.
Members save up to 40% off list price.
HTML for Linking to Page
Page URL

Related Items

Technical Paper / Journal Article
Technical Paper / Journal Article
Technical Paper / Journal Article
Technical Paper / Journal Article