The R49 is a 13-mode steady-state diesel engine test cycle introduced by ECE Regulation No. 49 and then adopted by Directive 88/77/EEC . It had been used for type approval emission testing of heavy-duty highway engines through the Euro II emission standard.
Since the Euro III stage (October 2000), the R49 cycle has been replaced by the ESC schedule. The R49 test remains a regulatory testing procedure in countries that still accept Euro II or earlier emission standards.
The R49 test is performed on an engine dynamometer operated through a sequence of 13 speed and load conditions. Exhaust emissions measured at each mode are expressed in g/kWh. The final test result is a weighted average of the 13 modes. The test conditions and weighting factors of the R49 cycle are shown in Table 1 and in Figure 1. The table also shows the weighting factors of the former US 13-mode test. The areas of circles in the graph are proportional to the weighting factors for the respective modes.
|Mode No.||Speed||Load, %||Weighting Factors|
Figure 1. ECE R49 Cycle
The running conditions of the R49 test cycle are identical to those of the US 13-mode cycle. The weighting factors, however, are different. Due to high weighting factors for modes 6 and 8 (high engine load), the European cycle is characterized by high average exhaust gas temperatures.