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Emission Test Cycles

Nonroad Low Load Application Cycle (LLAC)

Time-speed-torque data points

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. The test was developed based on real world application cycles provided by John Deere. Due to low exhaust temperatures, the LLAC proved challenging for Tier 4 baseline engines with SCR aftertreatment, which produced high NOx emissions over the cycle.

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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.