Browse Publications Technical Papers 2005-01-3748

Acquisition of Corresponding Fuel Distribution and Emissions Measurements in HCCI Engines 2005-01-3748

Optical engines are often skip-fired to maintain optical components at acceptable temperatures and to reduce window fouling. Although many different skip-fired sequences are possible, if exhaust emissions data are required, the skip-firing sequence ought to consist of a single fired cycle followed by a series of motored cycles (referred to here as singleton skip-firing). This paper compares a singleton skip-firing sequence with continuous firing at the same inlet conditions, and shows that combustion performance trends with equivalence ratio are similar. However, as expected, reactant temperatures are lower with skip-firing, resulting in retarded combustion phasing, and lower pressures and combustion efficiency. LIF practitioners often employ a homogeneous charge of known composition to create calibration images for converting raw signal to equivalence ratio. Homogeneous in-cylinder mixtures are typically obtained by premixing fuel and air upstream of the engine; however, premixing usually precludes skip-firing. Data are presented demonstrating that using continuously-fired operation to calibrate skip-fired data leads to over-prediction of local equivalence ratio. This is due to a combination of lower reactant temperatures for skip- versus continuous-fired operation, and a fluorescence yield that decreases with temperature. It is further demonstrated that early direct injection can be used as an alternative approach to provide calibration images. The influence of hardware modifications made to optical engines on performance is also examined.


Subscribers can view annotate, and download all of SAE's content. Learn More »


Members save up to 17% off list price.
Login to see discount.
Special Offer: Download multiple Technical Papers each year? TechSelect is a cost-effective subscription option to select and download 12-100 full-text Technical Papers per year. Find more information here.
We also recommend:

Diesel Fuel Ignition Quality as Determined in the Ignition Quality Tester (IQT)


View Details


Internal Flow and Cavitation in a Multi-Hole Injector for Gasoline Direct-Injection Engines


View Details


New Developments in Fuel Injector Atomizer Layouts for Port Fuel Injection Applications to Meet PL6 and ULEV Requirements


View Details