Most truck and bus operators will be familiar with medium and low-SAPS engine oils. These feature reduced quantities of the additives sulphated ash, phosphorous and sulphur which, when burned in the engine, form metallic ashes on the particulate filter.
Unlike the unburned carbon particles that are also collected by the filter, these do not burn off in service, are not removed by forced filter regeneration, and can only be purged from the filter if it is removed and undergoes a specialist process.
If this task is ignored, there are two possible outcomes. Either the vehicle will derate its power output, then go into limp mode and eventually stop, or pressures and temperatures within the filter can will rise to the extent that a spectacular exothermic reaction can take place. In other words, it explodes!
Current medium or low-SAPS oils reduce the build-up of ash on the filter compared to conventional lubes, but cannot prevent it, and the need for a removal, and clean or replacement after 400,000 km cannot be avoided even on well-maintained trucks running long distances.
But long before any warning lights are illuminated, the accumulation of deposits in the filter will have begun to impact on a truck’s fuel consumption. The increase in exhaust backpressure raises pumping losses, plus periodic active regeneration increases the amount of diesel burned, as active regen involves either activating a diesel burner in the exhaust system or additional fuel being injected into the combustion chamber once the exhaust valves are open.
The product of at least seven years of research, Delo 600 ADF is claimed by Texaco to drastically reduce ash formation by eliminating phosphorous from the additive package, and reducing sulphated ash content from one to 0.4 per cent. It is further claimed that this is without impairing its qualities as a lubricant, either in terms of engine protection or drain interval, thanks to Texaco’s patented Omnimax additive technology replacing the traditional anti-wear additives.
Besides the three per cent improvement in fuel economy, filter cleansing cycles are extended by up to 250 per cent: meaning that in some cases operators may not have to undertake this process at all, with consequent savings in cost and downtime. In fact, the product exceeds Volvo’s tough T-13 oxidation test limit of 360 operational hours by 100 per cent, making it a candidate for extended drain intervals where appropriate.
Further testing in North America on a Daimler OM501LA engine revealed it bettered the ICEA E9 standard for piston deposit formation by 94 per cent, and eliminated cam wear on a Cummins ISB engine relative to API CK-4 limits.
Currently available as a 10W-30 or 15W-40, Delo 600 ADF meets ACEA E6 and E9 performance standards, along with API CK-6, CJ-4, CI-4, CI-4 Plus AND CH-4 approvals.
A spokesman for Texaco said Delo 600 ADF was “only the start of the Omnimax story,” and hinted that further approvals to ACEA E8 and E11 standards were on the way, together with ultra-low viscosity Omnimax lubricants to meet forthcoming ACEA F-series approvals.
Additionally, the Omnimax technology could allow engine designers to specify smaller, cheaper and lighter PM filters, if current cleaning intervals were retained.