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The benefits associated with the use of oxygen-containing diesel fuels in passenger cars are quite well described in the literature. This work describes the results of an 18-meter EEV city bus fueled with diesel fuel with the addition of 10% v/v of triethylene glycol dimethyl ether. This compound was chosen because it was effective in reducing exhaust emissions from light duty diesel vehicles. Emission tests (CO, HC, NOx and PM) of the city bus were performed over SORT (Standardized On-Road Tests) cycles using portable exhaust gas analyzers - PEMS. Significant differences in the emission of exhaust components were observed in individual SORT cycles. The level of road emissions reduced as the traffic smoothness increased, i.e. from the SORT 1 to SORT 3 cycle. The largest reduction in bus emissions associated with the use of the oxygenated additive (triethylene glycol dimethyl ether) applies to carbon monoxide and ranges from 50% for the SORT 3 cycle up to 90% for the SORT 1.

Hydrogen Fuel-Cell (HFC) technology is popular in Asia (mainly Japan), the US (chiefly California) and Europe. HFC is mostly used in passenger cars and urban buses. HFC technology is also being introduced to railway transport. Hydrogen-powered trains are an attractive alternative to diesel trains, in particular on nonelectrified railways - where roughly 70% of the world’s 200 000 locomotives operate today - and in the markets of Europe and the US (together about 55 000 diesel locomotives today). Besides avoiding carbon emissions, hydrogen trains reduce noise and eliminate local emissions of NOX and particulates. Since they use significant amounts of hydrogen, the required infrastructure is limited and can be immediately utilised. Hydrogen-powered trains are already being introduced for light-rail vehicles and regional railways - such as the trams produced by the China South Rail Corporation.

There is a growing appreciation for using buses powered by alternative fuels in urban transport. Considered as such are city bus with engines fuelled with LNG and hybrid bus. This article, as shown above, provides a comparison of road exhaust emissions from three city buses: one with a CI engine fuelled with diesel fuel, and the other with a SI engine fuelled with LNG and Hybrid bus. Both vehicles (CI and LNG) conformed to Euro VI emission standard (hybrid bus EEV), and the tests were carried out in real traffic conditions. Equivocal opinions about differences in emissions from those types of buses, among others - CO2 and NOx emissions, were the underlying cause of the tests. The comparative study was carried out along the same urban routes during bus trips over the following days in similar traffic conditions. Exhaust road emission was determined based on the vehicle's curb weight and route length, and operating fuel consumption.

The paper describes the measurement of PM emission from an excavator engine under actual operating conditions. The exploration of the relations between the engine operating parameters and its emissions requires measurements under actual conditions of engine operation. The specificity of the emission measurements, PM in particular, requires technologically advanced measuring devices. The situation gets even more complicated when, beside the PM mass. The particle size distribution and number (PN) also need to be measured. An important technical issue is the difficulty in fitting the measurement equipment in/on the vehicle in operation (e.g. excavator), which is why the presented investigations were carried out in a laboratory under simulated operation. The laboratory technicians applied load to the engines through the excavator hydraulic system.