Nonroad Low Load Application Cycle (LLAC)
The Nonroad Low Load Application Cycle is an engine dynamometer test developed at the SwRI for the California Air Resources Board (CARB) for potential use in Tier 5 emission standards for nonroad engines. Later in the CARB Tier 5 development process, the LLAC was replaced with the Nonroad LLC cycle.
The LLAC was developed based on real world application cycles provided by John Deere. Due to low exhaust temperatures, the test proved challenging for Tier 4 baseline engines with SCR aftertreatment, which produced high NOx emissions over the cycle.
Figure 1. Nonroad Low Load Application Cycle (LLAC)
The LLAC cycle duration is 4337 seconds, and the average power is about 15% of the engine maximum power. The cycle was generated to assume a minimum accessory load of 5% at all times, except for the one segment that involves motoring (road transport).
Acknowledgement: This article based in part on information provided by Chris Sharp of the Southwest Research Institute.