Expanding the operating envelope of advanced combustion enigines (ExxonMobil)

CATEGORY: ADVANCED COMBUSTION 
Expanding the operating envelope of advanced combustion enigines (ExxonMobil)

Type	Patent
Inventor	Lisa I. Yeh
Inventor	Jeffrey H. Farenback-Brateman
URL	Free Full Text Source:  http://www.google.com/patents/US8671891
Assignee	Exxonmobil Research And Engineering Company
Patent Number	US8671891 B2
Issue Date	Mar 18, 2014
Abstract	The invention provides enriched fuels and methods that expand the operating envelope of an advanced combustion engine during operation in an advanced combustion mode (e.g. HCCI mode). Enriched fuels and methods of the invention facilitate efficient combustion over a wide range of engine loads, and the need for EGR, VVT, NVO, rebreathing, or multiple fuel injection is either reduced or eliminated.

Improved Chemical Kinetics Numerics for the Efficient Simulation of Advanced Combustion Strategies

CATEGORY: ADVANCED COMBUSTION
SAE Int. J. Engines 7(1):243-255, 2014, doi:10.4271/2014-01-1113.
Improved Chemical Kinetics Numerics for the Efficient Simulation of Advanced Combustion Strategies
Federico Perini, Bishwadipa Das Adhikary, Jae Hyung Lim, Xingyuan Su, Youngchul Ra, Hu Wang, Rolf Reitz, University of Wisconsin
Abstract:
Examines the computational efficiency of an innovative sparse analytical Jacobian chemistry solver called ‘SpeedCHEM.’ It features both direct and Krylov-subspace solution methods for maximum efficiency for both small and large mechanism sizes.
Researchers coupled the code with a high-dimensional clustering algorithm for grouping homogeneous reactors into clusters with similar states and reactivities, to speed-up the chemical kinetics solution in multi-dimensional combustion simulations. They validated the methodology within the KIVA-ERC code, and the computational efficiency of both methods was studied for different, challenging engine combustion modeling cases, including dual fuel, dual direct-injection and low-load, multiple-injection RCCI, direct injection gasoline compression ignition (GDICI), and HCCI engine operation using semi-detailed chemistry representations. Results of their analysis demonstrate that consideration of detailed chemistry need not constitute a bottleneck, allowing use of larger and more refined meshes.
Full Text Source (Subscription or Fee): http://papers.sae.org/2014-01-1113/

Comparison of Low Temperature Combustion Strategies for Advanced Compression Ignition Engines with a Focus on Controllability

CATEGORY: ADVANCED COMBUSTION
Combustion Science and Technology, Published online: 08 Nov 2013, DOI:10.1080/00102202.2013.858137
Comparison of Low Temperature Combustion Strategies for Advanced Compression Ignition Engines with a Focus on Controllability
Adam B. Dempsey*, N. Ryan Walker, Eric Gingrich & Rolf D. Reitz
a Department of Mechanical Engineering , University of Wisconsin – Madison, Engine Research Center , Madison , WI
Abstract
Reports a study of a number of low temperature combustion strategies using single cylinder engine experiments. The strategies involved a premix the majority of the fuel and which did not require EGR to achieve ultra-low NOx and soot emissions for low- to mid-load engine operation.
These types of advanced compression ignition combustion strategies have been shown to have challenges with combustion phasing control. Accordingly, investigators focused on comparisons of engine performance and emissions, combustion sensitivity to intake conditions, and the ability to control any observed sensitivity through the fuel injection strategy. While these are steady state engine experiments, they show a given combustion strategies controllability on a cycle-to-cycle basis. The combustion strategies are fully premixed dual fuel Homogeneous Charge Compression Ignition (HCCI), dual fuel Reactivity Controlled Compression Ignition (RCCI), and single fuel Partially Premixed Combustion (PPC). Both dual fuel HCCI and RCCI were able to readily correct the observed sensitivities through the global fuel reactivity with no negative implications on the NOx emissions. However, single fuel PPC was unable to correct for the observed combustion phasing sensitivity and, in some cases, had negative implications on the NOx emissions.
Full Text Source (Subscription or Fee): http://www.tandfonline.com/doi/abs/10.1080/00102202.2013.858137