Performance of a Direct Injection of IC Engine on SVO and Biodiesel from Multiple Feedstocks

Syndi Nettles-Anderson,Jean-Nicolas Enjalbert,Daniel B Olsen,Jerry J Johnson

doi:10.4236/jpee.2014.28001

Abstract

Straight Vegetable Oil (SVO) is a promising biofuel with a low energy input to energy output ratio. Successful use of SVO in engines depends on engine performance, wear and emissions. This study focuses on short term engine emissions and performance. This research uses oils produced in Colorado as a full diesel fuel substitute in a modified single cylinder engine. This engine testing was conducted in the laboratory. The test engine was a Yanmar TF140E, which is naturally aspirated and uses low pressure (～140 bar) mechanical direct injection. The engine fuel system was modified to accommodate a 2-tank custom SVO kit. The SVO was heated to 75 °C. Fuel economy and emissions measurements were performed for petroleum diesel, four different vegetable oils (sunflower, canola, camelina, and soybean) and their biodiesel derivatives. Fuel mass flow, oxides of nitrogen (NOX), total hydrocarbons (THC), carbon monoxide (CO), and particulate matter were measured. No engine degradation was experienced through approximately 50 hrs of testing on SVO and 50 hrs of testing on biodiesel. Overall engine emissions for SVO and biodiesel, with the exception of THC for biodiesel, were higher than petroleum diesel. More favorable biofuel emissions comparisons to diesel are expected with other engine designs based on data from various literature sources. Data comparing raw and refined SVO indicate that refined vegetable oil produces lower particulate matter (PM) emissions. General trends were observed showing that oils with higher levels of polyunsaturated fats (e.g. C18:1, C18:2, and C18:3) produce higher levels of NOX and THC’s.

Highlights

The combustion of Straight Vegetable Oil (SVO) in internal combustion engines has shown conflicting results in emissions, power, and engine longevity
Studies indicate that SVO should never be considered for longterm use in Internal Combustion (IC) engines, while waste vegetable oil has been fueling converted vehicles for years
More favorable biofuel emissions comparisons are expected with other engine designs based on data from various literature sources

Summary

Introduction

The combustion of Straight Vegetable Oil (SVO) in internal combustion engines has shown conflicting results in emissions, power, and engine longevity. Oilseeds often chosen for SVO fuel have been chosen based on local availability and viscosity, without consideration of the variation in lipid composition within or between multiple crop species. The primary objective for this research was to compare engine efficiency and emissions from SVO, biodiesel, and petroleum diesel using vegetable oil from four locally produced oilseed species. High oleic sunflower, canola, camelina and soybean were chosen as test fuel sources. Each oilseed source was crushed and filtered for use in the engine. SVO is oil obtained from oilseed crops by cold pressure crushing, clarifying, and filtering, without solvents or chemical modification. The same oil source for testing SVO and biodiesel was maintained so the lipid acid content would be consistent, except for soybean. The soybean oil used for the biodiesel was from commercial soybean oil that was refined and bleached, while the soybean oil for the SVO test was raw oil from a Colorado field (Section 2.1)

Results

Discussion

Conclusion