Session: 02-02: Alternative CI Fuels, Ignition, and Combustion Strategy

Paper Number: 190945

190945 - A Single-Cylinder Engine Evaluation of Ethanol With Combustion Enhancer As a Replacement for Diesel Fuel 

Abstract: 

Because it is easy and safe to store, can be made renewably, and can have beneficial effects on combustion, ethanol has been used in spark ignited engines as an additive to gasoline or as a replacement for gasoline.  While it is generally considered a poor fuel for compression-ignition (CI) engines due to its low cetane number and high heat of evaporation, its ease of storage and broad availability make it an attractive alternative fuel in some markets. In this paper, we investigate the concept of an ethanol-fueled CI engine where fuel additives were used to make the ethanol suitable as a diesel replacement for use in a CI engine.

The goal of this work is to demonstrate that ethanol treated with a combustion enhancer (CEN) could be used as a diesel fuel replacement. Ethanol fuel with several concentrations of the CEN was evaluated experimentally to investigate combustion stability, emissions, and thermal efficiency using baseline diesel hardware. With 4% CEN, the engine operated from idle to 83% rated power and was constrained to a narrow range of injection timing and rail pressure due to misfire.  At higher concentrations, the ignition delay was shortened and operability improved.

Compared to diesel, ethanol showed significantly lower soot emissions while unburned hydrocarbon and carbon monoxide emissions were higher. Nitrogen oxide emissions and thermal efficiency could be competitive with diesel at most conditions with optimal tuning. Suboptimal tuning was generally challenging due to incomplete combustion or misfire. Additionally, compared to diesel, the lower energy density of ethanol reduced the maximum power of the engine. Despite the challenges of using ethanol in a CI engine, the CEN enables the engine to run on ethanol without the need for hardware modifications. However, the fuel may require an increase in CEN content up to 8% or more for improved operability.  

Presenting Author: Adam Klingbeil Wabtec Corporation

Presenting Author Biography: Dr. Adam Klingbeil is a Senior Engineer in the Advanced Engine Technologies group at Wabtec. He received his Master’s degree from the University of Wisconsin-Madison in 2002 and his Ph.D. from Stanford University in 2007. Dr Klingbeil has contributed to more than 20 conference and journal publications and is co-inventor on over 60 patents. With 18 years of industry experience in large engine testing and combustion system optimization for low emissions and improved fuel efficiency, Dr Klingbeil has helped to develop key performance technologies used in Wabtec’s Tier 3, Tier 4 and NextFuel locomotives.

Authors:

Adam Klingbeil Wabtec Corporation
Richard Samson Eurenco
Tristen Tinar Southwest Research Institute
Khanh Cung Southwest Research Institute
Scott Ellis Southwest Research Institute