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Technical Paper
James F. Sinnamon, David R. Lancaster, John C. Stiener
An analytical spray model is described which can be used to calculate the penetration and trajectory of a spray in an engine combustion chamber with air swirl. The model consists of integral continuity and momentum equations written for a steady-state gas jet. The model contains adjustable entrainment and drag parameters evaluated from experimental data. A special single-cylinder, see-through engine and a schlieren optical system were used to study transient liquid fuel sprays under varied conditions. These experimental observations were used to determine appropriate values for the adjustable parameters in the spray model. Comparisons between model calculations and the experimentally observed sprays are presented for a wide range of conditions.
Technical Paper
S. R. Reddy, M. L. McMillan
A new laboratory test, the Diesel Fuel Cold Filterability Test (DIFCOFIT), has been developed to predict fuel filter plugging by diesel fuels containing flow improver additives, and to understand how flow improvers interact with diesel fuels to affect low-temperature operation of diesel vehicles. In the test, a sample of diesel fuel is cooled at a rate of 2°C/h and filtered at 1°C decrements below its cloud point through 37, 125, and 420 μm screens to determine filter plugging temperatures. Flow improver effectiveness was found to depend on additive concentration as well as fuel n-paraffin concentration and distribution. Mechanisms are proposed to explain the effectiveness of flow improvers on the basis of these factors.
Technical Paper
J. Gary Smyth, Roy Douglas
Since its inception, the internal combustion (IC) engine has undergone continuous improvements with respect to efficiency and performance. Future regulatory and environmental requirements are not only driving still further improvements, but also extending the propulsion system efficiency through hybridization and potentially obsolescing the IC engine with hydrogen fuel cells. This paper describes the potential IC engine improvements to meet tomorrow’s challenges and the associated business and technical challenges in obtaining these challenges. The future propulsion system portfolio mix will encompass gasoline engines, diesel engines, hybrids and fuel cells. The critical role of the IC engine in this portfolio mix is examined.
Journal Article
Raymond Turin, Oguz Dagci, Man-Feng Chang
The focus of this paper is an air charge estimator for engine control system applications which do not feature a mass air flow (MAF) sensor. The proposed approach, beyond its independency of a MAF sensor, is designed to be compatible with the confines of a typical production control system configuration. The air charge estimation algorithm is based on mean-value models for the manifold pressure dynamics and the gas flows through the throttle and valve orifices. It involves nominal static models for the volumetric efficiency of the engine and for the throttle discharge coefficient. The static models for those parameters are complemented with correction factors that are adjusted on-line. The update of the volumetric efficiency correction is implemented in the form of a Kalman-filter which uses the difference between the measured and the modeled manifold pressure as an error metric.
Technical Paper
Terence J. Clancy, William A. Elliott, Donald E. Malen
A method for structural analysis using cast plastic scale models is presented. The method was used to predict the dynamic structural response of a vehicle powertrain using one-half scale cast Polyurethane models of the engine block and transmission case. The results of the model test program allowed the design to be modified to meet structural objectives before tooling commitments were made.
Technical Paper
M. Cardone, A. Senatore, D. Buono, G. Cipolla, A. Chianale, A. Leo
Euro 6 European legislation emission limits, expected to be introduced around the 2014 timeframe, Lean NOx Trap (LNT) Aftertreatment technology is today considered one the of candidate technology to allow diesel Engine to meet the future Euro 6 limit. The working principle of the LNT is based on its capability to store the NOx engine out during the normal lean (excess of Oxygen) phase operation condition of the Diesel engine. The NOx will be then reduced in a dedicated regeneration phase which consist in creating for relatively short time a rich exhaust gas condition inside the LNT. The LNT regeneration strategy lead to run a Diesel engine with a rich mixture out of the combustion as a Gasoline engine. This can be obtained using advanced air and fuel management. The fuel management implicate the use of delayed injections (after and/or post injections) which can have a direct impact on oil dilution.
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