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A biodiesel fuel, obtained from Jatropha seed in China, was tested in a direct injection, high pressure common-rail diesel engine for passenger cars. Effects of biodiesel on particle number and size distribution of the diesel engine are studied using an Engine Exhaust Particle Sizer (EEPS). Base petroleum diesel fuel, 10% and 20% v/v biodiesel blends with the base petroleum diesel fuel, the biodiesel fuel (B0, B10, B20 and B100 fuels) were tested without engine modification. For all test fuels, the particle number and size distribution show unimodal or bimodal log-normal distribution, with a nucleation mode peak value in 6.04nm to 10.8nm particle diameter, and with an accumulation mode peak value in 39.2nm to 60.4nm particle diameter.

In this investigation, a phenomenological model, that predicts the particulate matter emission (PM) of diesel engines, has been developed. The model is based on the formation mechanisms of nitrogen oxides (NOx) and PM diesel engines. It can predict the emission concentration of PM via the emission concentration of NOx. The concentrations of oxidants, local pressure and equilibrium temperature influence the concentrations of NOx and PM inside diesel engines. Experiments were carried out in two six-cylinder, heavy-duty, turbocharged and intercooled diesel engines. Comparisons of the model results with the experimental data show good agreement. The model is useful for computer simulations of electronically controlled diesel engines, as well as electronic control unit (ECU) designs for diesel engines.

With increasingly severe atmospheric environmental problems, diesel car emissions have attracted broad attention for its main contribution to air pollutant. Alternative fuels become a hot research point in vehicle for rapidly consuming of fossil oil resources. Biodiesel and GTL (gas to liquid) fuels are two typical alternative fuels for diesel fuel. Low blend ratio (≤10%) biodiesel and GTL fuels can be used in a diesel engine without modifying the engine’s configuration. It is important to investigate the difference of low blend ratio biodiesel and GTL fuels used in the same diesel car and to find the optimum one. Gaseous and particle emissions from a light duty diesel car with B10 (10% biodiesel from cooking oil +90% diesel, v/v) and G10 (10% GTL fuel +90% diesel, v/v) was investigated. It was equipped with high pressure common rail system, cooled EGR and DOC and was tested on a chassis dynamometer under NEDC mode.

An EURO 3 certified common rail diesel engine was fueled with pure petroleum diesel (EURO 4 standard) and three different alternative blended diesel fuels, 10% biodiesel blended diesel (B10), 10% gas to liquid blended diesel (G10) and 10% water emulsified diesel (E10). Tests were performed at different engine speeds and load states. Particle number concentration and size distribution data were obtained from an engine exhaust particle sizer (EEPS). Over all the working conditions, total particle and nucleation mode particle number concentration among these fuels from high to low were in this order: B10, E10, pure diesel and G10. Proportions for nucleation mode particle over all the operating states in that order were 89%, 82%, 59% and 66%. Particle size distributions of B10 and E10 presented bimodal logarithmic distributions with outstanding nucleation mode peaks at all working conditions.

Regulated gaseous and particulate matter (PM) emissions in the exhaust from a heavy duty diesel engine with biodiesel fuel were studied, and the emission characteristics of PM and polycyclic aromatic hydrocarbons (PAHs) emissions in PM were highlighted. In the experiment, pure diesel fuel and B10 (a blend of diesel and biodiesel fuels with the volume ratio of 9 to 1) fuel were chosen. The study shows that, compared to the pure diesel, the emissions of PM, soluble organic fractions (SOF) and PAHs from the heavy duty diesel engine decrease when the engine burns B10 fuel, and the nitrogen oxides (NOx) emission slightly increases, while the unburned hydrocarbon (HC) and carbon monoxide (CO) emissions also decline. Among the detected 12 kinds of PAHs, emission concentrations of 10 kinds of PAHs from the engine with B10 descend. Especially Benzo(a)pyrene equivalent toxicity (BEQ) analysis results show that the BEQ of B10 fuel decreases by 15.2% compared to pure diesel.

Effects of biodiesel fuel on nucleation mode particles were studied on a direct injection, high pressure common-rail diesel engine for passenger cars. Particle number and size distribution of the diesel engine were obtained using an Engine Exhaust Particle Sizer (EEPS). The base petroleum diesel, three different blend ratios of petroleum diesel/biodiesel (10%, 20% and 50% v/v biodiesel blend ratios), and the pure biodiesel fuel (obtained and converted from Jatropha seed in China) (B0, B10, B20, B50 and B100 fuels) were tested without engine modification. Experiments were performed on a series of engine operating conditions. The particle number size distribution of the engine shows unimodal or bimodal log-normal distribution. With the biodiesel blend ratios increasing, the number of nucleation mode particles increases at all test engine operating conditions and accumulation mode particles decreases at most engine operating conditions.

In this study, a composition-based particulate matter (PM) model of direct injection diesel engines has been formulated and developed to simulate PM emission. The PM model is based on formation mechanisms of main compositions of PM: soot and soluble organic fraction (SOF). Firstly, two models for soot and SOF emissions are established respectively, then, the two models are integrated into a whole PM model. The soot emission model is given by the difference between a primary formation model and an oxidation model of soot. The soot primary formation model is the Hiroyasu soot formation model, and the Nagle and Strickland-Constable model for the soot oxidation is adopted. The SOF emission model is based on an unburned hydrocarbons (HC) emission model, and the HC model is given by the difference between a HC primary formation model and a HC oxidation model.

As a type of alternative fuel, biodiesel has advantages in reducing greenhouse gases and ensuring energy security. Compared with petroleum diesel, biodiesel has different lower calorific value, oxygen content and octane number that would raise problems when the unoptimized common rail diesel engine is fueled with biodiesel or its petroleum diesel blends. Among these problems, decreasing full load torque output and increasing NOx and BSFC are significantly important. Fuel injection parameter calibration and optimization experiments are carried out in an in-line 6-cylinder 8.82 liter turbocharged and intercooled common rail diesel, which is equipped with Denso ECD-U2 fuel injection system, SCR (Selective catalytic reduction) and DPF (diesel particulate filter). To avoid after-treatment apparatus' coupling influence and re-calibration, emission measure point is set in front of catalysts. The experiment adopts B20 biodiesel as test fuel.