Suzuki joins Automotive Grade Linux
Finnish electric powertrain company Visedo raises €20M to support global expansion; SRPM technology

Sandia Labs forms Spray Combustion Consortium to improve engine design

Sandia National Laboratories has formed an industry-funded Spray Combustion Consortium to better understand fuel injection by developing modeling tools. Control of fuel sprays is key to the development of clean, affordable fuel-efficient engines.

Intended for industry, software vendors and national laboratories, the consortium provides a direct path from fundamental research to validated engineering models ultimately used in combustion engine design. The three-year consortium agreement builds on Department of Energy (DOE) research projects to develop predictive engine fuel injector nozzle flow models and methods and couple them to spray development outside the nozzle.

Consortium participants include Sandia and Argonne national laboratories; the University of Massachusetts at Amherst; Toyota Motor Corp.; Renault; Convergent Science; Cummins; Hino Motors; Isuzu; and Ford Motor Co. Data, understanding of the critical physical processes involved and initial computer model formulations are being developed and provided to all participants.

Sandia researcher Lyle Pickett, who serves as Sandia’s lead for the consortium, said predictive spray modeling is critical in the development of advanced engines.

Most pathways to higher engine efficiency rely on fuel injection directly into the engine cylinder. While industry is moving toward improved direct-injection strategies, they often encounter uncertainties associated with fuel injection equipment and in-cylinder mixing driven by fuel sprays. Characterizing fuel injector performance for all operating conditions becomes a time-consuming and expensive proposition that seriously hinders engine development.

—Lyle Pickett

Industry has consequently identified predictive models for fuel sprays as a high research priority supporting the development and optimization of higher-efficiency engines. Sprays affect fuel-air mixing, combustion and emission formation processes in the engine cylinder; understanding and modeling the spray requires detailed knowledge about flow within the fuel injector nozzle as well as the dispersion of liquid outside of the nozzle. However, nozzle flow processes are poorly understood and quantitative data for model development and validation are extremely sparse.

The Office of Energy Efficiency and Renewable Energy Vehicle Technologies Office supports the unique research facility utilized by the consortium to elucidate sprays and also supports scientists at Sandia in performing experiments and developing predictive models that will enable industry to bring more efficient engines to market.

—Gurpreet Singh, program manager at the DOE’s Vehicle Technologies Office

Consortium participants already are conducting several experiments using different nozzle shapes, transparent and metal nozzles and gasoline and diesel type fuels. The experiments provide quantitative data and a better understanding of the critical physics of internal nozzle flows, using advanced techniques like high-speed optical microscopy, X-ray radiography and phase-contrast imaging.

The experiments and detailed simulations of the internal flow, cavitation, flash-boiling and liquid breakup processes are used as validation information for engineering-level modeling that is ultimately used by software vendors and industry for the design and control of fuel injection equipment.

The goals of the research are to reveal the physics that are general to all injectors and to develop predictive spray models that will ultimately be used for combustion design.

Predictive spray modeling is a critical part of achieving accurate simulations of direct injection engines. As a software vendor specializing in computational fluid dynamics of reactive flows, the knowledge gained from the data produced by the consortium is invaluable to our future code-development efforts.

—Kelly Senecal, co-founder of Convergent Science

Consortium participants meet on a quarterly basis where information is shared and updates are provided.



Some months ago we were talking about the mahle combustion pre-chamber that was supposed to reduce fuel consumption by 20% and now they are still in the dark and invest money to study what is already implemented, LOL.


Orbital had the idea of air and fuel spray with a direct inject two cycle, clean,
efficient and good power to weight.

Brian P

This is not a simple matter. The two-stroke concept - a further development of it which does not use air-assisted injection - is in current production by Rotax/Bombardier for snowmobile and outboard motor applications, but a piston-ported two-stroke will always have a trade-off between adequate lubrication of the piston rings for long life, and oil escaping either into the combustion system from the intake ports or out into the exhaust from the exhaust ports, leading to HC and PM emissions. Exhaust temperature tends to be low with a lot of dilution on two-strokes, which is not good for catalyst light-up after cold start. These applications do not require compliance with automotive emission standards nor is the engine expected to last 300,000 km with only basic maintenance. For applications requiring compliance with automotive or Euro 4 motorcycle emission standards, piston-ported two-stroke is not the answer.

The Mahle pre-chamber is a lean-burn application which is evidently being used in Formula 1 to reduce fuel consumption at part load. This is also troublesome if you have to meet modern automotive emission standards. If you have to run stoichiometric to keep a catalyst happy, it's doubtful that this acoomplishes anything. Maybe if the prechamber is stoichiometric without a lot of recirculated exhaust and the main chamber is where the EGR is kept, it might be of some benefit.

What needs research, and is surely the focus of this, is somehow addressing the fine particulate emissions that have become apparent with direct-injection four-strokes, improving the speed of combustion without encountering detonation so that the compression ratio can be increased for better efficiency and so that combustion is completed at that higher compression ratio, and controlling piston and exhaust valve temperatures to reduce the need for enrichment under load - the latter being a particularly significant issue for downsized forced-induction engines.

Advanced engines that rely on HCCI under at least some operating conditions will be relying on this, too.

The comments to this entry are closed.