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Condensed soot coming out of vehicular exhaust is commonly classified as organic carbon (OC) and elemental carbon (EC). OC can be directly emitted to the atmosphere in the particulate form (primary carbon) from the tailpipe or can be produced by gas-to-particle conversion process (secondary organic carbon, SOC). Under typical atmospheric dilution conditions, most of the semi-volatile material is present in the form of soot. SOC holds wider implications in terms of their adverse health and climate impact. Diesel exhaust is environmentally reactive and it has long been understood that the ambient interaction of exhaust hydrocarbons and NOx results in the formation of ozone and other potentially toxic secondary organic carbon species. The current emission norms look at the primary emissions from the engine exhaust. Also, research efforts are geared towards controlling the emissions of primary carbon.

The development of advanced gasoline direct injection (GDI) injector requires in-depth investigations of macroscopic and microscopic spray characteristics. Over the years, GDI injectors have undergone exponential improvement to be able to deliver fuel at high injection pressure. High fuel injection pressure (FIP) leads to superior fuel atomization, and consequently superior fuel-air mixing. Present investigations aim to improve our fundamental knowledge of the furl-air mixture preparation mechanisms of different test fuels. Experiments were conducted to study spray breakup of GDI injector. This study focuses on the spray investigations using Phase Doppler Interferometry (PDI) for the measurement of various spray related studies such as determination of arithmetic mean diameter (AMD), sauter mean diameter (SMD) and spray droplet velocity distributions.

Fuel injection pressure (FIP) is one of the most important factors affecting diesel engine performance and particulate emissions. Higher FIP improves the fuel atomization, which results in lower soot formation due to superior fuel-air mixing. The objective of this spray study was to investigate macroscopic and microscopic spray parameters in FIP range of 500-1500 bar, using a solenoid injector for biodiesel blends (KB20 and KB40) and baseline mineral diesel. For these test fuels, effect of ambient pressure on macroscopic spray characteristics such as spray penetration, spray area and cone angle were investigated in a constant volume spray chamber (CVSC). Microscopic spray characteristics such as velocity distribution of droplets and spray droplet size distribution were measured in the CVSC at atmospheric pressure using Phase Doppler Interferometry (PDI).

Due to the increasingly stricter emission legislations and growing demand for lower fuel consumption, there have been significant efforts to improve combustion efficiency, while satisfying the emission requirements. Homogenous Charge Compression Ignition (HCCI) combustion offers significant efficiency improvements compared to conventional gasoline engines. However, due to the nature of HCCI, fully homogeneous charge HCCI combustion can be realized only in a limited operating range. Control of HCCI engines to obtain the desirable operation requires understanding of how different charge variables influence the cyclic variations in HCCI combustion. Under certain operating conditions, HCCI engines exhibit large cyclic variations in ignition timing. Cyclic variability ranging from stochastic to deterministic patterns can be observed. One important design goal for engine development is to minimize cyclic variability.

Adverse health effects of particulate matter (PM) originating from diesel engine exhaust are largely attributed to the complex chemical composition of the exhaust species. This study was set out to characterize particulate emissions from a Euro-III-compliant modern automotive common rail direct injection (CRDI) sports utility vehicle (SUV) diesel engine operated at different loads at rated engine speed (1800 rpm), employing diesel and 20% biodiesel blends (B20) produced from Karanja oil. This study is mainly divided into two main sections, first one includes the gravimetric analysis in order to assess the amount of Benzene Soluble Organic Fraction (BSOF) and trace metals using Inductively Coupled Plasma-Optical Emission Spectrometer (ICPOES). The second section includes real-time measurements for Organic Carbon (OC), Elemental Carbon (EC) and total particle-bound Polycyclic Aromatic Hydrocarbons (PAHs).