Clean Diesel V 

Clean Diesel V builds on 16 years of Clean Diesel Consortium Programs managed by Southwest Research Institute® (SwRI®). Clean Diesel V will begin immediately upon the successful completion of Clean Diesel IV on November 1, 2007. The Consortium will encompass four to five projects focused on the development of advanced combustion engines, including projects such as:

• Full operating range HCCI engine development
• Dilute diffusion combustion engine development
• Expansion of the advanced SwRI low-temperature combustion technology
• Integration of cost-effective aftertreatment systems

OBJECTIVES

The Consortium is designed to develop pre-competitive technologies that member companies can then incorporate into their products. Project goals are to achieve the most stringent emissions regulations at thermal efficiencies exceeding the 2004 model year levels. The heavy-duty emissions goals are the US 2010 and EURO VI on-road and the Tier IV off-road standards. The light-duty emissions goals are the US Tier 2, Bin 5 and EURO VI and, as a stretch target, US Tier 2, Bin 2.

PREVIOUS CLEAN DIESEL SUCCESSES

Clean Diesel I (1991–1995) focused on the development of EGR (exhaust gas recirculation) technology for control of engine-out NOx emissions. The program demonstrated achievement of 2004 emissions regulations in 1994. This technology is now in production on all on-road diesel engines.

Clean Diesel II (1995–1999) examined in detail the effects of dilute combustion on engine-out emissions. The focus was on advanced EGR systems, including development of model-based control technology. Fuel injection system development included a system that demonstrated the advantages of rapid mixing using small holes and high pressures (up to 300 mPa), a concept that is now becoming part of the production solution.

Clean Diesel III (1999–2003) initially focused on the development of diesel aftertreatment systems, including SCR+cDPF and LNT+cDPF systems. US 2010 compliant emissions levels were demonstrated using an LNT+cDPF system in 2003. Low operating temperature emissions control was approached using advanced low temperature combustion technology and included incorporation of VVA (variable valve actuation) technology. Development of full operating range HCCI, including the fuel effects, was initiated in Clean Diesel III.

Clean Diesel IV (2003–2007) continued development of the full operating range HCCI engine concept. Acceptable operation with peak loads of 11 Bar was demonstrated in a multi-cylinder HCCI engine using low octane gasoline specially formulated for HCCI operation. Preliminary data indicated that Tier II, Bin 2 diesel technology is possible.

PROPOSED PROJECTS (Partial List)

Tier II, Bin 5 and Bin 2
This project will be continued from CD IV to incorporate variable effective compression ratio and VVA, and high injection pressure with multiple injections. Advanced combustion strategies will be used to minimize engine-out emissions and control the exhaust gas composition and temperature for optimum operation of the post-combustion emissions control system (PM and NOx). The focus of the project will be to achieve the Tier 2, Bin 5 emissions regulations at the lowest possible fuel consumption, with a goal of achieving a peak thermal efficiency of 40 percent. A stretch goal will be to achieve Tier 2, Bin 2. Diagnostics strategies of aftertreatment and combustion control devices are also to be developed. Fuel property effects will be determined and the effects of the advanced combustion processes on lubricant degradation will be closely monitored.

Massive EGR in Heavy-Duty Diesel Engines
This project will be continued from CD IV. The goal is to achieve 2010 HD on-road emissions standards using minimum post-combustion NOx emissions control. The approach incorporates the use of massive EGR for in-cylinder NOx control. High boost is required to maintain the power density at acceptable overall air-fuel ratios for control of soot formation. Small injection nozzle holes and high injection pressure will be used to increase the fuel-air mixing rates for additional control of the soot formation processes. System optimization will require incorporation of advanced model-based control. Fuel property effects will be determined, including the use of oxygenated fuels. Lube oil condition will be closely monitored to determine the effects of the low temperature combustion.

Full-Time HCCI in Medium-Duty Engine
This project will be continued from CD IV. The goal of this project is to achieve operation in HCCI mode over the entire operating range of a typical medium-duty diesel engine. The approach involves optimization of the engine design simultaneously with optimization of the fuel formulation. Key elements for continued development include refinement of the fuel formulation developed in Clean Diesel IV, continued development of the engine combustion system, and optimization of the model-based control system required for successful operation of this type of engine. Lube oil quality will be monitored closely to document the effects of this mode of engine operation.

Real-Time Water Emulsions (RTWE) + EGR versus SCR+EGR
A novel fuel injection system was developed in Clean Diesel III which allowed for real-time control of the water content of fuel-water emulsions (RTWE). The system was used in Clean Diesel III to demonstrate that the use of water-in-fuel emulsions provides significant emissions benefits in terms of simultaneous reduction of both NOx and PM emissions. The data demonstrated that for every one percent water added to the fuel, approximately one percent reduction in NOx and approximately 1.5 percent PM reduction can be achieved. The goal of this project is to further optimize the system and to integrate it along with an appropriately designed EGR and combustion system, in order to eliminate the need for post-combustion NOx control in a heavy-duty diesel engine.

Engine Thermal Management for High Efficiency
All of the advanced low-emissions combustion modes involve the use of high levels of dilution. This in turn places extreme demands on the engine boost system, especially those based on the use of turbochargers. High mass flow requirements and low exhaust temperatures are the key issues. The goal of this project is to incorporate the use of thermal barrier coatings in the combustion chamber to minimize the heat rejection to the coolant and to more effectively use this energy to drive the boost system. A secondary goal is to document the effects of the thermal barrier coatings on the engine during operation in the various advanced combustion modes.

MEMBERSHIP AND BENEFITS

Interested companies may join the Clean Diesel V Consortium at any time during the four-year program. A yearly renewable contract is offered to members. One advantage of Consortium membership is that the impact of the yearly contribution is multiplied by the number of participants. SwRI’s internal research program involving control algorithms and modified combustion concepts will be shared with Consortium members. SwRI will aggressively pursue patent applications for technology developed during the Clean Diesel V program, and consortium participants will receive a royalty-free license to use the technology.

For additional information about Clean Diesel V Consortium, please visit www.cleandieselv.swri.org.
 

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