The use of hydrogen in spark ignition engines as a supplementary fuel can enhance combustion and reduce toxic emissions. Difficulties in hydrogen storage and production limit its use in internal combustion engines. This paper investigates the performance of a spark ignition engine with the addition of a mixture of hydrogen (H 2 ) and oxygen (O 2 ) into the intake manifold. Hydrogen is produced by an alkaline electrolyser and consumed simultaneously to eliminate the need for a storage device. Flow rates of 0 and 10 L/min H 2 -O 2 mixture were introduced into the manifold. No flow, or 0 L/min, refers to the case without hydrogen, and 10 L/min represents the case with hydrogen. Brake torque, fuel consumption, nitrogen oxides, carbon monoxide, and total unburned hydrocarbons were measured. The results show that brake power, brake torque, and nitrogen oxide emissions increased with the addition of H 2 -O 2 , while total unburned hydrocarbons, carbon monoxide emissions, and brake-specific energy consumption decreased.

Ethanol is a promising alternative fuel, due to its renewable biobased origin. Also, it has lower carbon content than diesel fuel and it is oxygenated. For this reason, ethanol is providing remarkable potential to reduce particulate emulsions in compression-ignition engines. In this study, performance of ethanol-diesel blends has been investigated experimentally. Tested fuels were mineral diesel fuel (E0D100), 15% (v/v) ethanol/diesel fuel blend (E15D85), and 30% (v/v) ethanol/diesel fuel blend (E30D70). Firstly, the solubility of ethanol and diesel was experienced. Engine tests were carried out to reveal the performance and emissions of the engine fuelled with the blends. Full load operating conditions at various engine speeds were investigated. Engine brake torque, brake power, brake specific fuel consumption, brake thermal efficiency, exhaust gas temperature, and finally exhaust emissions were measured. Performance of the tested engine decreased substantially while improvement on smoke and gaseous emissions makes ethanol blend favorable.

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Public transportation fuel consumption modeling shows a great importance because of economic and environmental aspects. Considering to the metropolises with millions of inhabitants with circulating thousands of buses that uses intercity lines, its importance is becoming vital in planning both operation of transportation company and city mobility planning. In this context a detailed fuel consumption modelling approach for public transportation buses was used for vehicle fuel consumption assessment during operation. The methodology was developed with IPG TruckMaker + AVL Cruise co-simulation environment following instantaneous speed, load and 3-D road data primarily besides model parameters. The model was validated at one of the most important public transportation axle of the world, Istanbul Metrobus System, at two direction which carries over ~1 million passenger daily in 24 hours operation with petrol engine buses. The comparison simulation/measurements showed that the proposed fuel consumption model is accurate and can predict fuel consumption behavior for public transit buses in a reliable band. In addition, this methodology can be used to investigate various powertrain and operating scenarios near future for more efficient public transportation with high reliability.