Small Combustion Engine Research Articles

Electrically heated catalyst enabling pollutants reduction in hybrid vehicles fueled with ethanol

Plug-in hybrid electric vehicles (PHEV) have the potential of combining the benefits of a renewable electric mix with biofuels. More recently, PHEV have been designed to be equipped with a small combustion engine known as range extender (RE), thus allowing an improvement in vehicle’s range while converting fuel energy through a highly efficient path. Despite being a convenient strategy for decarbonizing light vehicles, the intermittent operation of the engine may create issues regarding the catalytic conversion of pollutants, yielding an increase in local harmful emissions. This drawback may be intensified depending on the used fuel. Hydrous ethanol is a promising alternative for gasoline and is already available in some countries, such as Brazil. However, ethanol has a great enthalpy of vaporization and it results in a charge cooling, affecting the catalyst warm-up and making the intermittent operation with ethanol more challenging. Hence, this study was motivated by the need of improving the catalytic efficiency of flexfuel RE operating with both gasoline and hydrous ethanol. Thus, a calibration was firstly performed to shorten the warm-up phase with ethanol. Then, an electrical heater was employed for accelerated catalyst heating, further improving emissions from ethanol operation, aiming at attaining future emissions regulations. Experimental tests were conducted in a vehicle under FTP72 cycle using a chassis dynamometer. The calibration adjustments resulted in a warm-up phase for ethanol <10 s longer than that for gasoline. The stable operation phase resulted in similar emissions for both fuels. On the cycle average, a reduction in CO for ethanol was observed, and although the methane and NOx emissions were slightly increased due to colder catalyst operation, significant improvements were obtained on a well-to-wheel (WTW) analysis. The use of an electrically heated catalyst (EHC) improved the emissions during the warm-up phase, significantly reducing the emission of NOx and non-methane organic compounds.

Measuring and Characterizing the Noise Emission of a Small Combustion Engine after Acoustical Topology Optimization of the Muffler

Measuring and Characterizing the Noise Emission of a Small Combustion Engine after Acoustical Topology Optimization of the Muffler

Sodium Silicide and the Development of the Portable Hydrogen Energy Market

With Li-ion batteries nearing their power limits and small combustion engines responsible for a disproportionate amount of pollution in the U.S., new hydrogen-storage technologies are essential to spark the transition to hydrogen energy. Sodium silicide, a new chemical molecule, enables the real-time and on-demand generation of hydrogen. This novel hydrogen-storage material and its derivatives facilitate high-performance, low-complexity and lightweight fuel cell systems (<3 kW), which are ideal for a number of industries and consumer applications. Transitioning the portable power market to this clean energy technology will result in higher energy efficiencies, a clean source of renewable energy, and a significantly lower environmental impact. Such a transition, however, requires the development of a hydrogen manufacturing supply chain that supports the growth of this new energy technology. Designs for hydrogen-generation cartridges and a high-volume manufacturing line will be presented.

Clean transport using blends of hydrogen and natural gas

Transport makes a significant contribution to total harmful emissions. For long term solutions to reducing emissions, the focus is on sustainable hydrogen and biofuels as alternatives to fossil fuels. In the transition era, natural gas (NG) and hydrogen reformed from NG are alternatives, used as fuel in ICEs. To research the effect of using blends of NG and hydrogen on emissions, Mobility Technology Research of HAN University (Arnhem, Netherlands) carried out the Clean Car project. This paper addresses the effect of gas composition and air-to-fuel ratio on performance and emissions of a small combustion engine.