Search Results

This study focused on the effect of engine oils on regulated emissions, particulates and fuel economy. Three engine oils of the same SAE grade (synthetic oil with poly alpha olefins (PAOs), Group III base oil, and Group III genuine oil with additive package) were used in one gasoline and one diesel vehicle. A GDI (Gasoline Direct Injection) vehicle and a diesel vehicle without DPF (Diesel Particulate Filter) were selected because those vehicles obviously emit more particulates than port-injection gasoline vehicles and diesel vehicles with DPF. A combined mode consisting of the US EPA emission test cycles FTP-75 and HWFET was used for these tests. HORIBA and PIERBURG gas analyzers were used to measure regulated emissions and fuel economy, respectively. Unregulated emissions and particulates were analyzed by FTIR and PPM-S, respectively. Samples (300 ml) of test engine oil were taken periodically just after each test, and the colors of the sampled oil compared.

Dimethyl ether(DME) is easily reformed into H2, since the chemical structure of DME does not feature direct C-C bonds, in contrast to diesel fuel. We have researched reforming catalysts for effectively generating H2 from the exhaust gases of a DME engine. The objective of this study is to evaluate the de-NOx performance of a combined system of RC(Reforming Catalyst) and LNT(Lean NOx Trap) for a DME engine according to reforming catalysts. The H2 generation of the reforming catalyst was observed under various conditions. CAT-A, CAT-B and CAT-C were prepared as reforming catalysts, and OC(Oxidation Catalyst) and LNT (Lean NOx Trap) were examined as commercial catalysts. The CAT-A catalyst has a higher amount of acid sites compared to the CAT-B and CAT-C catalysts. The CAT-A which is a mixing of mordenite and γ-Al2O3, has the highest H2 yield. However, the H2 yield decreased in the reforming reaction when CO2, NO and O2 coexisted.

This study investigates the potential of dual-fuel combustion for reducing emissions with same power. Dual-fuel combustion controls the combustion by two fuels with different auto-ignition characteristics and this study uses DME and diesel that show different characteristics of evaporation and auto-ignition. In the previous work, we focus on the characteristic of combustion and emissions under single cylinder engine and ignition is done by compression ignition. Pre-mixture is formed by injecting low-pressure DME into an intake manifold and high-pressure fuel (diesel or DME) is injected directly into the cylinder. Both direct diesel injection and port fuel injection reduced the significant amount of Soot, CO and NOx in the homogeneous charge compression ignition engine due to present of oxygen in DME.

The characteristics of diesel spray injected into the cylinder provide crucial clues to the perception of the combustion performance in a compression ignition engine. In this study, five different diesel common rail injectors were examined which have different hole numbers, orifice sizes, jet cone angles, and hydraulic flow rates. Both the macroscopic and microscopic characteristics of diesel sprays were compared through Mie-scattered light imaging and PDA (Phase-Doppler anemometry) measurements. Seven hole injector with smaller hole was found to give better air/fuel mixing and favorable droplet size compared with other injectors. To evaluate the feasibility of achieving lower emission level with the different diesel sprays, the combustion and emission characteristics in case of 6 and 7 hole injectors were investigated under the same fuel flow rate condition in a light duty DI diesel engine.

Natural gas is one of the most promising alternative fuels for automotive vehicles. However, composition of natural gas varies between the originating fields and may be further modified due to processing and additional mixing. These variations are known to affect engine performance and emissions through changes in fuel metering and combustion characteristics. In the present study, it was examined the effect of gas composition on vehicle performance such as fuel economy, driveability and exhaust emissions. Analysis was made of using 3 types of NGVs which were manufactured by auto maker and 6 different fuels which were selected in consideration of the variation in fuel composition on the worldwide market. These results may be utilized to develop natural gas engine in auto maker and/or to establish the fuel standard in the refuelling station.