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For domestically produced passenger car gasoline fuelled vehicles, the forthcoming task of emissions compliance in India (Bharat-IV by 2010) may require a more detailed knowledge of transient engine behaviour by Indian engineers. Under steady state conditions and with reasonable fuel preparation, three-way catalytic converters can remove around 98% of legislated pollutants. However, during cold start and gear changes, the transient emissions are not fully converted by the catalyst; the cold start alone contributing typically 90% of the total Cycle Hydrocarbon (HC) emissions for the Euro- IV drive cycle [1]. This paper presents data measured pre and post the three-way catalyst on a EURO- III compliant European manufactured production Port-Fuel-Injection (PFI) gasoline engine running on a FTP drive cycle. The transient emissions were measured using fast response gas analyzers, with time response giving resolution at better than engine firing frequency.

An accurate prediction of residual burned gas within the combustion chamber is important to quantify for development of modern engines, especially so for those with internally recycled burned gases and HCCI operations. A wall-guided GDI engine has been fitted with an in-cylinder sampling probe attached to a fast response NDIR analyser to measure in-situ the cycle-by-cycle trapped residual gas. The results have been compared with a model which predicts the trapped residual gas fraction based on heat release rate calculated from the cylinder pressure data and other factors. The inlet and exhaust valve timings were varied to produce a range of Residual Gas Fraction (RGF) conditions and the results were compared between the actual measured CO2 values and those predicted by the model, which shows that the RGF value derived from the exhaust gas temperature and pressure measurement at EVC is consistently overestimated by 5% over those based on the CO2 concentrations.

The gaseous and particulate emissions from a diesel passenger car have been studied during cold start and Diesel Particulate Filter (DPF) regeneration events occurring during the New European Drive Cycle (NEDC). During the initial phase of the cycle, Diesel Oxidation Catalyst (DOC) light-off was seen to be highly dynamic with catalyst efficiency changing dramatically with changes in catalyst temperature. Accumulation mode particulate emissions were sampled directly from the exhaust after the DPF. From cold start with a clean (regenerated) DPF, accumulation mode particle emissions were seen to be very much higher than those from a loaded DPF. This accumulation mode slip lasted only approximately 200 seconds. During regeneration of the DPF, the oxidation of trapped soot was associated with a large tailpipe emission of nucleation mode particles.

Cyclic combustion variability (CCV) is an undesirable characteristic of spark ignition (SI) engines, and originates from variations in gas motion and turbulence, as well as from differences in mixture composition and homogeneity in each cycle. In this work, the cycle to cycle variability on combustion and emissions is experimentally investigated on a high-speed, port fuel injected, spark ignition engine. Fast response analyzers were placed at the exhaust manifold, directly downstream of the exhaust valve of one cylinder, for the determination of the cycle-resolved carbon monoxide (CO) and nitric oxide (NO) emissions. A piezoelectric transducer, integrated in the spark-plug, was also used for cylinder pressure measurement. The impact of engine operating parameters, namely engine speed, load, equivalence ratio and ignition timing on combustion and emissions variability, was evaluated.