Search Results

A turbocharged lean burn natural gas engine was upgraded to operate on a blend of hydrogen and natural gas (HCNG). Tests were carried out to determine the most suitable H2/NG blend for H2 fractions between 20 and 32 vol%. A 20 vol% H2 content was found to provide the desired benefits when taking into consideration the engine and vehicle performance attributes. A full engine map was developed for the chosen mixture, and was verified over the steady-state AVL8 cycle. In general, the HCNG calibration included operation at higher air-fuel ratios and retarded spark timings. The results indicated that the NOx and NMHC emissions were reduced by 50% and 58% respectively, while the CO and CH4 emissions were slightly reduced. The HCNG engine torque, power and fuel consumption were maintained the same as for the natural gas fuel. The chassis dynamometer transient testing confirmed large NOx reduction of about 56% for HCNG operation.

The purpose of this paper is to outline the effects of oxygen enrichment on the performance of a spark ignited single cylinder Ricardo research engine fueled with natural gas. Substituting gasoline with natural gas, under stoichiometric conditions, brings about a decrease in power output of a dedicated gasoline engine. This reduction in power is quantified in this paper for both fuels under stoichiometric conditions as well as for different fueling rates, for natural gas. Subsequently, the effects of oxygen enrichment are reviewed in terms of: volumetric efficiency, flame propagation velocity, coolant temperature, exhaust gas temperature, spark advance, brake mean effective pressure, brake horsepower. The use of oxygen enriched air results essentially in: 1 a significant increase in brake horsepower, 2 improved lean limits and reduction of spark advance, 3 a lower brake thermal efficiency.

In an effort to reduce CO2 emissions, governments are increasingly mandating the use of various levels of biofuels. While this is strongly supported in principle within the energy and transportation industries, the impact of these mandates on the transport stock’s CO2 emissions and overall operating efficiency has yet to be fully explored. This paper provides information on studies to assess biodiesel influences and effects on engine performance, driveability, emissions and fuel consumption on state-of-the-art Euro IV compliant Toyota Avensis D4-D vehicles with DPNR aftertreatment systems. Two fuel matrices (Phases 1 & 2) were designed to look at the impact of fuel composition on vehicle operation using a wide range of critical parameters such as cetane number, density, distillation and biofuel (FAME) level and type, which can be found within the current global range of Diesel fuel qualities.