You won't get any argument from Jim McGeehan that oil is the lifeblood of the engine. And he'll no doubt agree that's especially true when it comes to the heavy-duty diesels truckers all over the world depend on.

Indeed, how to protect each successive crop of cleaner diesel engines with appropriate motor-oil formulations is the major challenge McGeehan and his fellow lubrication engineers are continuously tackling.

It's hard work. But in McGeehan's view, it's about more than helping engine manufacturers protect the innards of powerplants that are becoming ever more sophisticated to meet tighter emissions limits.

“Each new API oil-service category that's been developed to date,” says McGeehan, “has resulted in an incremental increase in oil quality. Now, the ASTM panel is working on the next proposed category (PC-9), which will address the lubrication needs of diesel engines designed to meet the EPA's stricter limits on NOx (oxides of nitrogen) emissions that become effective in October ’02. Engine makers will be using cooled exhaust-gas recirculation (EGR) technology to lower NOx levels.

“The arrival of EGR makes for a much bigger challenge than we faced in developing previous oil categories,” he continues. “This will be the first time exhaust gas that's cooled will be put into the cylinders. This is quite a shift in engine design. But oil must be formulated to ensure the same level of engine durability is maintained as we now have.”

According to McGeehan, the ASTM panel's work will result in having oils qualified to the PC-9 spec available in time for the ’02 engines. He says this classification process will be complete when those formulations are approved to carry what will likely be in the next API donut, “CJ-4.”

But there's no escaping the proverbial drawing board. The next challenge is coming up fast. “The 2007 EPA regs will require incredibly low NOx and particulate emissions. To meet those limits, engines will have to use aftertreatment technology, such as NOx catalysts and ceramic particulate traps,” McGeehan points out. “And we will still have EGR in place. We will have to formulate oils that ensure the same level of durability for ’07 engines — and that will be compatible with the aftertreatment systems. It will be a very different challenge again.”

McGeehan reports yet another important issue for lube engineers is unfolding — the advent of de facto global oil specs. “Back in October 2000, a group of engine makers came up with the first global oil specification: DHD-1. It rolls into one the requirements of the latest API diesel-oil category, CH-4, and the specs required by European and Japanese engine makers. DHD-1 both improves engine durability and prevents misapplication of product.”

He says that Chevron, with its familiar Delo 400 15W40 multigrade, was the first oil supplier to claim it could meet DHD-1. “We did that because we recognize globalization is taking place among equipment manufacturers,” McGeehan says. “And they are feeling the same pressure to reduce emissions worldwide. In fact, engine makers recently met to lay the groundwork for what will be DHD-2.” He says that spec will address engines — such as the ones meeting EPA's ’07 regs — that use aftertreatment systems and run on ultralow-sulfur fuel.

It certainly sounds like the industry's lube engineers will be burning plenty of midnight oil over the next five or more years. However, McGeehan says it will be worth it. “The end result will be diesel engines that are extremely clean and very efficient,” he states. “And because of all that will go into oil formulations, they will be durable, too.”

Name: James McGeehan, manager of engine oil technology, Chevron Products Co., Richmond, Calif.

Background: McGeehan is a certified engineer, member of the Institution of Mechanical Engineers (U.K.) and an SAE Fellow. As chairman of the ASTM Heavy-Duty Engine Oil Classification Panel, he helped establish the API oil-service categories CE, CF-4, CG-4 and CH-4. The panel is currently working on development of a new category (PC-9) for EGR diesel engines. McGeehan has won numerous SAE awards for his research and ASTM work.

Each month this new column will look at emerging truck technology issues through the eyes of some of the industry's leading engineers.