A new category of diesel engine oil, Delo 400 SD SAE 15W-30, addresses the growth of severe duty applications in on- and off-highway markets. The API CJ-4 formulation uses Chevron Products’ patent-pending Isosyn technology, 
developed with an eye to the demands of “severe duty” cycles. It suits advanced engines equipped with features like four-valve heads, super-charging, turbo-charging, direct injection, higher power density, intercooling, full electronic management of fuel and emissions systems, exhaust selective catalytic reduction, exhaust gas recirculation, and exhaust particulate filters.
“The increase in severe duty operations is due to changing driving habits on highway, including shorter haul lengths, growth in intermodal delivery, and more stop-and-go operations, while off-highway has new energy-efficient equipment that helps minimize fuel usage by cycling engines from load to no load,” says Chevron Products Manager, Americas Marketing Jim Gambill. “In order for engines to last as long as they’re designed to, we need to reassess maintenance practices for this type of operation. A critical part of this process is to find an engine oil which is not just heavy duty, but severe duty.”
Contributing to severe duty cycles are abrupt changes in truck operating conditions, such as trucks that are prohibited from idling and must have their engines turned off; trucks subject to stop-and-go in heavy traffic or city delivery; and, situations where engine cooling may be stressed like towing heavy loads on steep grades or cycling between fully loaded and unloaded in off-road applications. Drivers report seeing higher engine operating temperatures in these conditions.
In addition to performance attributable to the Isosyn technology, product developers cite among key Delo 400 SD SAE 15W-30 benefits a) maximum vehicle utilization and minimal downtime resulting from oxidation stability and deposit control; and, b) improved fuel economy, up to 0.7 percent in Class 8 trucks, compared to conventional SAE 15W-40 oils.
Delo 400 SD SAE 15W-30 is formulated for on- and off-highway applications including EPA 2010- and Tier 4-compliant low emission diesel engines with selective catalytic reduction, diesel particulate filter and exhaust gas recirculation. It will meet a range of OEM requirements for oil, including specs for Cummins, Mack, Paccar and Volvo engines. Additionally, it is recommended for use in select engines from Caterpillar, Daimler and Detroit. For users with a mix of engine brands, Delo 400 SD SAE 15W-30 is backwards compatible with previous API Oil Service Categories, and engine models where XW-30 oils are appropriate as noted by the OEM. Users can simplify their inventory and dispensing systems, saving money, space and handling time. — Chevron Products Co., www.ChevronDelo.com, www.thisissevereduty.com
SEVERE DUTY CYCLE EFFECT ON ENGINES
Chevron enlisted Southwest Research Institute to gauge oil temperatures in heavy-duty diesel engines subjected to frequent loaded and no load cycles. Vehicles were driven 40 miles then engines shut off for 10 minutes. In the two minutes after shutdown, turbocharger oil temperature increased 25°F before starting to cool. Turbocharger oil temperature increased by up to 67°F when engines were restarted 10 minutes after shut down. Higher engine component temperatures increase oil oxidation, adding to the probability of deposit build up and viscosity loss that reduces the lubricant’s ability to protect the engine.