AVL 8-Mode Heavy-Duty Cycle

The AVL 8-Mode test is a steady-state engine test procedure designed to closely correlate with the exhaust emission results over the US FTP transient cycle for heavy-duty engines, especially in regards to NO_x emissions. The test includes 8 steady-state modes. The composite value is calculated by applying weighing factors on the modal results.

The sequential engine operating points are as follows:

**Table 1**
AVL 8-Mode Heavy-Duty Cycle
Mode	% Engine Speed*	% Load	Weight factor†
1	0	0	35.00
2	11	25	6.34
3	21	63	2.91
4	32	84	3.34
5	100	18	8.40
6	95	40	10.45
7	95	69	10.21
8	89	95	7.34
* Normalized speed: 0% = low idle, 100% = rated speed † Relative weight factors, not normalized (they do not add to 100%)

The relative weights of particular modes are represented by the area of bubbles in Figure 1.

**Figure 1.** AVL 8-Mode Heavy-Duty Cycle