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 [2871]. 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Since the Euro III stage (October 2000), the R49 cycle has been replaced by the ESC schedule.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.

Table 1
ECE R49 and US 13-Mode Cycles
Mode No. Speed Load, % Weighting Factors
R49 US
1 idle - 0.25/3 0.20/3
2 maximum
torque
speed
10 0.08 0.08
3 25 0.08 0.08
4 50 0.08 0.08
5 75 0.08 0.08
6 100 0.25 0.08
7 idle - 0.25/3 0.20/3
8 rated
power
speed
100 0.10 0.08
9 75 0.02 0.08
10 50 0.02 0.08
11 25 0.02 0.08
12 10 0.02 0.08
13 idle - 0.25/3 0.20/3
[SVG image]

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.