Low Emission
Idle Systems



Benefits of LEI Systems

  • Reduces visible emissions
    (unburned hydrocarbons and particulate material) during idle and other low load conditions
  • Economical
  • Durable, low maintenance
  • Automated operation requires no user input
  • Simple installation fits to existing engine without alteration

What is Low Emission Idle (LEI)?

Engenious™ Engineering’s patented LEI system is supplementary hardware designed for use under low load conditions. By alternating the left and right cylinder banks at an engine’s lowest speeds, combustion is improved, resulting in a significant reduction in emissions such as unburned hydrocarbons.

Compatible with standard EMD diesel and GE FDL series engines, the LEI system is a practical and economical way for you to reduce visible emissions and fuel costs for locomotives in switch yards and long-haul service.

How Does Low Emission Idle Work?

The LEI is an alternating bank system, running the engine on half of its cylinders during modes of low engine specific output (idle and low RPM). The additional load placed on the firing cylinders causes them to burn diesel fuel more efficiently. This improvement in combustion results in a reduction of unburned hydrocarbons.

As locomotives commonly spend anywhere from 40-75% of their time idling, this means a huge reduction in fuel costs and emissions. Cleaner exhaust is also apparent when throttling up after extended periods of idling, visible proof of cleaner emissions and more complete combustion.

When the LEI system is active, a slight and momentary drop in engine speed is detectable as the engine changes operational banks. The frequency of bank-to-bank operation change is adjustable, ranging from every 15 seconds to every 4 minutes.

The LEI system disables instantly when the control inputs change to another operation mode and returns the engine to normal operation.

Contact Us


6411 Pacific Hwy. East Tacoma, WA 98484

(253) 312-7888

(253) 922-2258