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The newly redesigned ECI Spark Ignited Prechamber (SIP) EMD conversion:

Napa Valley Wine Train 73: First ECI SIP conversionThis conversion system builds on the successes of the ECI dual fuel EMD conversion, and adds an ECI-developed prechamber to provide a clean and reliable ignition source.

This design has a well-proven track record, with the very first example providing power for the Napa Valley Wine Train #73 for well over a decade.

Since its initial release, the system has been greatly refined and is ready to help you take your EMD fleet with you in the ineveitable transition to alternative fuels.


  • Fuel cost savings
  • Clean Emissions
  • Fully rated horsepower
  • Retrofit system - expands capability and adds value to your present investment
  • Lower maintenance costs & improved longevity due to cleaner fuel
  • Appropriate for rail or stationary applications
  • Environmentally responsible technology

How it works

Low Pressure Direct Injection

ECI Gas Injection Cycle

The ECI SIP natural gas conversion is designed for the EMD 645 2-cycle diesel engine. It utilizes a low-pressure direct injection system, a prechamber spark ignition system, and an advanced full-authority electronic engine controller.

By means of an electro-hydraulic valve incorporated into the head, natural gas is injected into the cylinder near the bottom of the piston's stroke when cylinder pressures are low. This requires far less injection pressure than late-cycle injection, and allows fuel and air to mix thoroughly during compression. The system achieves full rated engine horsepower with only 120-150 psi of injection supply pressure.

The ECI Spark Ignited Prechamber is installed in place of the EMD diesel injector, and at the top of the piston's stroke provides enough ignition energy to light the lean mixture of natural gas and air in the main combustion chamber. This oil-cooled prechamber is supplied with natural gas separately from the main chamber, and the engine controller is called upon to continuously adjust the prechamber air-fuel ratio for ideal ignition.

In order to reduce emissions and improve the quality of combustion at low engine speed and load, ECI employs innovative control techniques to manipulate combustion characteristics. The spark ignited, 100% gas EMD 645 runs smoothly from Low Idle to Notch 8.

ECI chose to use low pressure injection over a high pressure system for a number of reasons. Low pressure injection:
- Extends the life of injectors and other fuel system components
- Improves the safety of the working environment on and around the engine
- Makes the fuel system simpler and more cost effective
- Avoids the complexity and energy consumption of a fuel pressure boosting system

These benefits of the ECI design translate into cost savings in both the initial investment and the operation of the equipment.

Specialized pistons and heads

At the heart of the SIP conversion are the specially designed ECI pistons and heads, originally developed for and used in the ECI dual fuel conversions.

The piston design incorporates a lower compression ratio and a modified crown shape to provide maximum power with natural gas.

The modified head is based on the OE EMD design and is specially cast to accomodate the ECI Gas Injector Valve (GIV).

This combination of purpose-designed head, piston, and specialty hydraulic/electronic gas injector valve is the polished product of years of development.

The power assemblies are applied using the standard diesel pack installation procedure, making the conversion straightforward and possible in any shop equipped for the overhaul of standard EMD engines.

gas piston

ECI's specialty piston on the right, next to a standard EMD piston. The ECI piston provides optimum combustion in the 100% gas engine.

Electronic Controls

System operation is governed by ECI's patented electronic control unit, or ECU. The ECU uses industrially proven electronic technology together with custom software to monitor and manipulate critical engine functions through a variety of sensors. It controls fuel injection timing, ignition timing, engine speed and generator excitation, smoothly handling wheel slip and traction motor series-parallel transition. The ECU is able to detect cylinder temperature imbalances, gas leaks, and equipment failures.
The ECU allows a maintenance technician to communicate with the system using either a simple digital information screen or a laptop computer and ECI software.

The ECI technician tool software can be run on a Windows laptop and allows a real-time, graphical display of critical engine parameters.

Cellular modem transmission capabilities are also available, which allow for data acquisition and fault history reviews from remote locations.


ECI's sophisticated engine control unit (ECU) performs a myriad of engine control functions, from injector valve sequencing to onboard diagnostics and logging performance histories.

Enhanced Cooling

In order to achieve full rated diesel power on turbocharged engines, there are modifications made to the existing engine air cooling system. Additional radiators, more effective after coolers, some piping and the addition of water circulating pumps work to reduce the high temperature air the turbocharger produces. This equipment fits easily inside of the long hood, with the addition of contoured sheet metal necessary for the new radiators. On LNG-fueled equipment, supplemental cooling is also claimed from the vaporization of the liquid natural gas on the fuel tender.

The additional air charge cooling is not required for roots-blown engine conversions.

aftercoolersSpecial 6-pass aftercoolers enhance temperature control and maximize horsepower

Radiators installed

Flared radiators similar to SD45 style, enhance cooling of charge air for better dual fuel performance

Make the conversion

LEI installed

Energy Conversions, Inc. is well equipped to take on the conversion of your workhorse EMD equipment to Natural Gas. Step into the lead in an industry destined to operate on alternative fuels in the near future.

With an ECI conversion system, you can make a small investment in existing equipment to begin developing in-house expertise and infrastructure to handle the growing popularity of Natural Gas.

6411 Pacific Hwy. East, Tacoma, WA 98424-1587, USA
(253) 312-7888, FAX (253) 922-2258
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