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Standards and legislation
Published in Abhishek Tiwary, Jeremy Colls, Air Pollution, 2017
Since it is clearly impractical to instrument all new models and drive the test cycle on real roads, emission test cycles are used which are a sequence of speed and load conditions performed on an engine or chassis dynamometer. The former will usually be more appropriate if the engine is a general-purpose power source that might be used in a wide range of applications (not necessarily vehicles). Emissions measured on vehicle (chassis) dynamometers (instrumented rolling roads) are usually expressed in grams of pollutant per unit of travelled distance, e.g. g km–1 or g mi–1. Emissions measured according to an engine dynamometer test cycle are expressed in grams of pollutant per unit of mechanical energy delivered by the engine, typically g (kWh)–1 or g (bhph)–1. Depending on the character of speed and load changes, cycles can be divided into steady-state cycles and transient cycles. Steady-state cycles are sequences of constant engine speed and load modes. Emissions are analysed for each test mode. Then, the overall emission result is calculated as a (time weighted) average from all test modes. In a transient cycle, the vehicle (or engine) follows a prescribed driving pattern which includes accelerations, decelerations and changes of speed and load. The final test results can be obtained either by analysis of exhaust gas samples collected over the duration of the cycle or by electronic integration of measurements from fast response, continuous emission monitors. Regulatory authorities in different countries have not been consistent in adopting emission test procedures and at least 25 types of cycle are in use. Since exhaust emissions depend on the engine speed and load conditions, specific engine emissions which have been measured on different test cycles may not be comparable.
Influence of ethanol-gasoline blended fuel on performance and emission characteristics of the test motorcycle engine
Published in Journal of the Air & Waste Management Association, 2022
Thanh Dinh Xuan, Dien Vu Minh, Binh Pham Hoa, Khanh Nguyen Duc, Vinh Nguyen Duy
The regulated gaseous emissions over the ECE driving cycle, an emission test cycle is a protocol contained in an emission standard were measured and evaluated in g/km. The emission rates of motorcycles for CO, NOx, HC are summarized in Figure 6. NOx and HC emissions of the bike using ethanol blends are lower than gasoline. However, NOx emissions have an opposite trend; they increased approximately 7.4% with E5, 12.3% with E10, and 18.51% with E20 due to the temperature increase. The reason for reducing CO and HC emissions is the rise in the percentage of ethanol and additive concentrations due to leaner combustion due to the presence of oxygen in ethanol. Owing to the leaning, CO and HC emissions decrease tremendously. In general, CO and HC emissions are reduced when concentration increases for all concentration blends.