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As on-highway heavy-duty diesel engine designs have evolved to meet tighter emission regulations, the crankcase environment for heavy-duty engine lubricants has become more challenging. The introduction of Exhaust Gas Recirculation (EGR) has allowed for significant reductions of exhaust emissions, but has led to increased oxidation and acid build-up in the lubricant. Engine lubricant quality is important to help ensure engine durability, engine performance, and reduce maintenance downtime. Increased acidity and oxidation accelerate the rate at which the lubricant quality is degraded and hence shorten its' useful life. This paper explores the use of a lube filter with a controlled additive release to maintain lubricant quality.

With the wider use of biofuels in the marketplace, a program was conducted to study the deposit forming tendencies and performance of E85 (85% denatured ethanol and 15% gasoline) in a modern Flexible Fuel Vehicle (FFV). The test vehicle for this program was a 2006 General Motors Chevrolet Impala FFV equipped with a 3.5 liter V-6 powertrain. A series of 5,000 mile Chassis Dynamometer (CD) Intake Valve Deposits (IVD) and performance tests were conducted while operating the FFV on conventional (E0) regular unleaded gasoline and E85 to determine the deposit forming tendencies of both fuels. E85 test fuels were found to generate significantly higher levels of IVD than would have been predicted from the base gasoline component alone. The effects on the weight and composition of IVD due to a corrosion inhibitor and sulfates that were indigenous to one of the ethanols were also studied.

With the wider use of Direct Injection Spark Ignition (DISI) vehicles in the marketplace, a program was conducted to develop a short-duration fuel injector fouling test. Once a specific driving cycle and base fuel combination was found to produce a significant increase in Long Term Fuel Trim (LTFT), several Deposit Control Additive (DCA) technologies were evaluated for their ability to keep the direct gasoline injectors clean. The increase in LTFT is indicative of fuel injector fouling and a corresponding decrease in flow through them. The test vehicles for this program were a 2008 General Motors Pontiac Solstice GXP equipped with a DISI 2.0 liter turbocharged I-4 and a 2008 Audi A4 equipped with a DISI 3.2 liter V-6 engine. A proprietary base fuel formulated to mimic a U.S. EPA 65th percentile fuel was tested to assess its deposit forming tendencies.

In recent years, the number of complaints and the severity of premature diesel fuel filter plugging have increased dramatically in the U.S. and Europe. These instances are often accompanied by longer start up times, poor drivability, and increased maintenance across different fuel filter applications. The rise in these instances of filter plugging is closely associated with the increasing prevalence of high pressure common rail (HPCR) fuel systems and the growing usage of biodiesel. Smaller pore size restrictions for fuel filters due to tighter clearances in HPCR injectors, coupled with contaminants from biodiesel and carboxylate salts in fuel, have been identified as accelerants of diesel fuel filter plugging. Testing protocols will be reported that can be used to screen contaminant-doped B10 fuels (10% FAME biodiesel in ULSD) to determine their propensity to plug fuel filters.