Effects on emissions of a diesel engine with premixed HHO

Abstract

Most parts of China suffer often from haze pollution, which has a huge impact on human health. Road traffic has made the largest contribution to the haze. Of all the kinds of vehicular systems, the diesel engine produces the most PM; therefore, to reduce haze pollution, it is necessary research methods to reduce the PM produced by diesel engines. HHO (Brown's gas, Rhode's gas and HRG) is formed from H 2 (60.79%) and O 2 (30.39%) as well as a small amount of water vapour and active substances, such as oxygen radicals (O) and hydroxyl radicals (OH), which have quite strong oxidizing properties in the engine process, stimulating the C-H chain reaction during the combustion period and accelerating the oxidation of HC, CO and PM emissions as a result. The influence of blending HHO with diesel on diesel engine emission characteristics is well-researched, based on an 186FA single-cylinder diesel engine. The HHO was combined with air in the intake pipe. The influence of HHO on the amount of CO, HC, NO and PM emissions was analysed by collecting data under various speeds and loads. Through MOUDI, particles of various diameters under the highest torque working conditions and declared working conditions were collected to analyse how HHO affected the particle mass distribution in different diameter ranges. The analysis showed that when the speed was stable, the quantities of CO, HC and PM created were decreased by adding HHO; in addition, HHO had the greatest effect on PM. As the load increased, the amount of CO, HC and smoke declined gradually, but the decline of NO was smaller comparatively. Moreover, after blending with HHO, the quantity of NO created increased by 9.52% when the diesel engine operated according to external characteristics, and the quantity of HC, CO and PM created decreased by 31.6%, 11.3% and 20.71%, respectively. Finally, the gross mass of the particles dropped 67.48% and 42.53% under the highest torque working conditions and declared working conditions, respectively, with the distribution of diameters moving to smaller sizes. Introducing HHO into diesel can effectively reduce the generation of PM, which plays a positive role in reducing haze pollution.

Influence of HHO Gas Addition on Combustion, Performance and Emission Characteristics of a CI Engine Fuelled with Used Cooking Oil Bio Fuel Blends

“…15 Variation of HC emission with respect to brake power and fuels During combustion, HHO generated more OH free radicals which enhance the reaction with the C-H chain due to its strong oxidizing properties and continuously oxidized unburned HC after the main combustion period. Thus, HC emission is reduced (35). Higher diffusion speed of hydrogen makes the fuel mixture gain better homogeneity, and therefore enhances the engine thermal efficiency and reduces the unburnt HC emissions (31).…”

“…Liu et al [23] reported that HHO accelerates the oxidation process and CO, HC and smoke emission declined gradually when load increased, but the drop of NO was comparatively smaller. Addition of 20% hydrogen leads poor diesel-air quantity which is not sufficient to develop healthy flame to ignite the hydrogen-diesel-air mixture.…”