Date of Award


Document Type

Open Access Master's Thesis

Degree Name

Master of Science in Mechanical Engineering (MS)

Administrative Home Department

Department of Mechanical Engineering-Engineering Mechanics

Advisor 1

Jeremy Worm

Committee Member 1

Jeffrey D. Naber

Committee Member 2

Scott A. Miers


This study experimentally investigated the effect of unintended water ingestion on a spark ignited internal combustion engine. Testing was performed on a 2.0L inline four cylinder turbocharged engine. Port water injection (with two different levels of atomization) was utilized to introduce water into the combustion system. Five speed / load points were tested from 1300 rpm 3 bar BMEP to 3250 rpm 15 bar BMEP. Testing was done with constant air charge as well as constant throttle emulating the in-vehicle scenario. The water to fuel ratio (W/F) was swept until COV of IMEP reached at least 20% and misfires were detected. With the addition of water, initially combustion performance degrades rapidly, however, once water vapor reaches saturation in the manifold, additional water has less of an impact, until ultimately in-cylinder water content is high enough to induce misfire. High engine loads are seen to be more resistant to combustion degradation due to water ingestion.