The effects of driving cycles and fuel composition on emissions from on-road motorcycles were studied with the objectives of understanding the effects of established drive cycles, quantifying the emissions from a more rigorous drive cycle, and determining the emission differences between various certification test fuels. Chassis dynamometer emissions testing was conducted on three motorcycles with engine displacements of 300 cc, 750 cc and 1200 cc. All of the motorcycles were Class II North American certified motorcycles with fuel injection and three-way catalysts. The motorcycles were tested using the North American certification cycle, also known as the Federal Test Procedure (FTP); the World Motorcycle Transit Cycle (WMTC); and a trial cycle based on real-world motorcycle driving, informally named the ‘Real World Driving Cycle’ (RWDC).
Per cycle exhaust emissions characterization included the following: carbon monoxide, oxides of nitrogen, hydrocarbons, carbon dioxide, total particulate matter, and a calculated determination of fuel economy. Along with an analysis of test cycle phase contributions and cumulative emissions over the test cycles. Engine torque was plotted against engine speed for each motorcycle and drive cycle to compare the engine demand of each drive cycle in relation to other cycles.
All three motorcycles had a 6-speed manual transmission and different shift points were used for each of the drive cycles as prescribed. Both the WMTC and the RWDC have higher speeds and acceleration rates compared to the FTP and the impacts of the more aggressive cycles on emissions were noted. Emissions of CO and NOX + HC increased with the more aggressive cycles. However, CO2 emissions decreased with the WMTC and RWDC and the resulting rate of fuel consumption increased. For all tests, emissions of PM were below 1 mg/km.
In addition, to Tier 2 EEE certification fuel (E0) results presented, Tier 3 EEE certification fuel (E10) and CARB LEV III fuel (E10) results will be presented separately along with additional emissions of methane, nitrous oxide, formaldehyde, acetaldehyde, and BTEX.