Search Results

Since the invention of the internal combustion engine, the contact between piston ring and cylinder liner has been a major concern for engine builders. The quality and durability of this contact has been linked to the life of the engine, its maintenance, and its exhaust gas and blowby emissions, but also to its factional properties and therefore fuel economy. While the basic design has not changed, many factors that affect the performance of the ring/liner contact have evolved and are still evolving. This paper provides an overview of observations related to the lubrication of the ring/liner contact.

The control of NOx emissions is the greatest technical challenge in meeting future emission regulations for diesel engines. In this work, a modal analysis was performed for developing an engine control strategy to take advantage of fuel properties to minimize engine-out NOx emissions. This work focused on the use of EGR to reduce NOx while counteracting anticipated PM increases by using oxygenated fuels. A DaimlerChrysler OM611 CIDI engine for light-duty vehicles was controlled with a SwRI Rapid Prototyping Electronic Control System. Engine mapping consisted of sweeping parameters of greatest NOx impact, starting with OEM injection timing (including pilot injection) and EGR. The engine control strategy consisted of increased EGR and simultaneous modulation of both main and pilot injection timing to minimize NOx and PM emission indexes with constraints based on the impact of the modulation on BSFC, Smoke, Boost and BSHC.

Adding oxygenates to diesel fuel has shown the potential for reducing particulate (PM) emissions in the exhaust. The objective of this study was to select the most promising oxygenate compounds as blending components in diesel fuel for advanced engine testing. A fuel matrix was designed to consider the effect of molecular structure and boiling point on the ability of oxygenates to reduce engine-out exhaust emissions from a modern diesel engine. Nine test fuels including a low-sulfur (∼1 ppm), low-aromatic hydrocracked base fuel and 8 oxygenate-base fuel blends were utilized. All oxygenated fuels were formulated to contain 7% wt. of oxygen. A DaimlerChrysler OM611 CIDI engine for light-duty vehicles was controlled with a SwRI Rapid Prototyping Electronic Control System. The base fuel was evaluated in four speed-load modes and oxygenated blends only in one mode. Each operating mode and fuel combination was run in triplicate.

A program to demonstrate the performance of advanced emission control systems in light of the California LEV II light-duty vehicle standards and the EPA's consideration of Tier II emission standards was conducted. Two passenger cars and one light-duty pick-up truck were selected for testing, modification, and emission system performance tuning. All vehicles were 1997 Federal Tier I compliant. The advanced emission control technologies evaluated in this program included advanced three-way catalysts, high cell density substrates, and advanced thermally insulated exhaust components. Using these engine-aged advanced emission control technologies and modified stock engine control strategies (control modifications were made using an ERIC computer intercept/control system), each of the three test vehicles demonstrated FTP emission levels below the proposed California LEV II 193,000 km (120,000 mile) ULEV levels.