Operating Experience and Teardown Analysis for Engines Operated on Biodiesel Blends (B20)

Abstract

Biodiesel has been used to reduce petroleum consumption and pollutant emissions. B20, a 20% blend of biodiesel with 80% petroleum diesel, has become the most common blend used in the United States. Little quantitative information is available on the impact of biodiesel on engine operating costs and durability. In this study, eight engines and fuel systems were removed from trucks that had operated on B20 or diesel, including four 1993 Ford cargo vans and four 1996 Mack tractors (two of each running on B20 and two on diesel). The engines and fuel system components were disassembled, inspected, and evaluated to compare wear characteristics after 4 years of operation and more than 600,000 miles accumulated on B20. The vehicle case history-including mileage accumulation, fuel use, and maintenance costs-was also documented. The results indicate that there was little difference that could be attributed to fuel in operational and maintenance costs between the B20-and diesel-fueled groups. No differences in wear or other issues were noted during the engine teardown. The Mack tractors operated on B20 exhibited higher frequency of fuel filter and injector nozzle replacement. Biological contaminants may have caused the filter plugging. A sludge buildup was noted around the rocker assemblies in the Mack B20 engines. The sludge contained high levels of sodium, possibly caused by accumulation of soaps in the engine oil from out-of-specification biodiesel. The Mack and Ford engines used similar pump-line nozzle fuel injection systems, but a much larger volume of fuel was recirculated in the larger Mack engines. This, along with duty cycle and engine loading, may account for the difference in performance of the two engine types operated on B20.

100,000-Mile Evaluation of Transit Buses Operated on Biodiesel Blends (B20)

“…Fraer et al [7] compared operation of cargo vans and truck tractors on B20 and petroleum diesel and performed teardown and analysis of engines and components. After four years of operation and 600,000 miles accumulated on B20, no differences in wear were noted.…”

Influences of Waste Cooking Oil-Based Biodiesel Blends on PAH and PCDD/F Emissions from Diesel Engines in Durability Testing Cycle

“…Many studies focused on the engine wear by long-term operation with static engine or field trail tests. The biodiesel blends (B20 to B100) were reported to have similar or even 30% less wear as compared to petroleum diesel after the durability tests (2-4 years, 200-500 h, or 30,000-200,000 km), because the unsaturated molecule could have better lubricity than the saturated ones (Clark et al, 1984;Kalam and Masjuki, 2002;Agarwai et al, 2003;Fraer et al, 2005;Proc et al, 2006;Agarwal et al, 2008). On the other hand, the biodiesels might lose their proven lubricity by auto-oxidation and corrosiveness for material degradation (Fazal et al, 2011).…”

Deposit Formation in the Holes of Diesel Injector Nozzles: A Critical Review

“…The papers [24][25][26][27][28] describe general engine tests with different types of biodiesel and biodiesel blends with normal diesel. A general description of deposits created on the injectors is given but no detailed characterisation or investigation was done.…”