The 6-mode cycle was used in Japan for testing of heavy-duty engines. It had been replaced by the newer 13-mode cycle and has only historical significance.

The engine was tested over 6 different speed and load conditions. The modes were ran in sequence and the duration of each mode was 3 min. Emissions were measured at each mode and averaged over the cycle using a set of weighting factors. The final test result was expressed as volumetric concentration in ppm.

There were two definitions of the test modes and weighting factors: one for diesel engines and another one for gasoline and LPG engines. The diesel cycle parameters are listed in the table below.

Table 1
Japanese Diesel 6 Mode Cycle
Mode Speed (% of nominal) Load (%) Weighting factor
1 idle - 0.355
2 40 100 0.071
3 40 25 0.059
4 60 100 0.107
5 60 25 0.122
6 80 75 0.286