This experimental study assesses the influence of ignition timing on emissions from a production four cylinder port injection spark ignition engine. The aim of this research was to evaluate the necessity of ignition timing correction when the regular gasoline vehicle is being adapted for the use of E85 fuel. Tests were conducted in the Alternative Fuels Research Laboratory of Latvia University of Agriculture in December 2013. The engine was fuelled with the ethanol-gasoline blend E85 or the commercial gasoline A95. The engine was tested within a vehicle in a chassis dynamometer in steady state conditions, which resemble driving at 50 km hE-1 and 90 km hE-1. The original engine control unit was replaced with a programmable one. Engine-out and tailpipe exhaust gas samples were taken and analysed with a FTIR-type analyser AVL SESAM. Carbon monoxide (CO), unburned hydrocarbons (HC), nitrogen oxides (NOx), acetaldehyde and unburned ethanol emission volumetric share is presented. CO, HC and acetaldehyde emissions were not affected by variation of the ignition timing within the tested range. NOx and ethanol emissions were reduced with the ignition timing retard. The emissions of CO, HC and NOx were reduced, when the engine was fuelled with the E85 fuel, comparing with the gasoline use. Ignition timing, optimized for the gasoline, was found suitable for the E85 fuel from the emission analyses point.

Biodiesel is renewable and environmentally friendly fuel, which can be used as a substitute for diesel in compression ignition (CI) engines. Nowadays it is also successfully used not only in transport sector, but also in commercial construction equipment and space heating. As the production of biodiesel (rapeseed methyl ester RME) is started now and is planned to grow rapidly, it is necessary to investigate biodiesel impact on engine performance and exhaust gas composition. This paper describes results of the investigation the aim of which was to find out the impact of biodiesel and its blends on an engine's dynamical, economical and ecological parameters in laboratory conditions on an engine test bench. The experimental work was done with an XD2P diesel engine in the Motor testing and biofuels laboratory of the Motor Vehicle Institute of Latvia University of Agriculture. The engine was fuelled on fossil diesel, rapeseed methyl ester (RME) and on blends of 5 (5RME) and 35 (35RME) percent RME/diesel fuel. The results indicated that power for biodiesel and blends was lower than with ordinary petrol diesel on average. 7.9% on 100RME and 3.6% on 35RME. The reduction in torque and increase in fuel consumption was observed. Experimental results showed that the addition of RME to diesel can significantly reduce oxides of nitrogen (NOx), carbon monoxide (CO), and absorption coefficient.

The use of the smoke released during the wood burning process to prepare food products is a centuries-long tradition, practically all over the world. However, during the combustion process, a group of compounds called polyaromatic hydrocarbons (PAHs) are formed in the flue gases, which are carcinogenic and condense during the smoking process and diffuse into the smoked food product. Therefore, permissible PAH norms have been set for food producers, which significantly complicate the use of wood. In the study, using a gas analyser, we measured the flue gases released during the burning of specially made, apple and grey alder wood pellets, with and without enrichment of the supplied air with ozone. The use of ozone does not ensure a higher burning temperature of pellets, but it stabilizes it – temperature fluctuations are significantly wider using non-ozonised air (697 to 817 and 611 to 817 ℃, respectively). The content of CO2, CO, as well as CH4 and N2O increases significantly in apple wood flue gases using ozonised air, while CH4 increases and N2O decreases in grey alder smoke. Which generally indicates specific reactions with ozone during combustion. Comparing the flue gases released during the burning of apple and grey alder wood pellets, grey alder smoke contains significantly more N2O and CO2 than apple wood pellet flue gases. On the other hand, using ozonised air in the combustion process increases N2O significantly in the flue gas of apple tree pellets compared to white alder.