Thousands of words have been written in the last year or so about the diesels you’ll be buying after October 1 of this year when the next round of emissions regulations kicks in. But you haven’t heard quite so much about the oils that will lubricate the so-called ’02 engines. As promised a couple of issues ago, we’ll fill that gap now.
All but one of the heavy-duty engine makers – the exception being Caterpillar – opted to use cooled exhaust-gas recirculation technology for 2002. An EGR system captures some exhaust air – 15% to 30% depending on load and throttle – and routes it through a cooler and then back into the combustion chamber. It replaces the same percentage of oxygen in the cylinder and thus lowers peak
flame temperatures, in turn reducing the nitrous oxides (NOx) formed by the
Lowering NOx, by about 50%, is the main goal of the ’02
However, the EGR process also has other effects: substantially more heat
rejection and thus higher operating temperatures, plus far more soot and
corrosive acids in the cylinder, all of which must be dealt with by the oil. Oils meeting the exacting new ‘CI-4’ standard have to neutralize those acids to prevent liner, ring, and bearing wear while also keeping the soot in suspension so that it
doesn’t gum up the works.
It’s a very big job, and in fact Mack’s E-7 EGR engine will need a bigger oil sump
because more lube is required to do the same work as before. The company’s EGR project leader Steve Heffner says the engine needs an extra eight quarts in the pan to stay with the current recommended 50,000-mile drain interval. Mack engines are the long-drain leaders today and require the least amount of oil amongst big-bore diesels. The fact that they’ll require 25% more for ’02 speaks volumes about the challenge engine lubes must meet generally.
Other engine makers will likely be more conservative than ever in recommending
extended drains, though most have yet to firm this up. Cummins already has, saying that drains should be at 25,000 miles for normal duty and 35,000 miles in lighter applications with its EGR products. That, however, may change for the better as we accumulate real-life experience with the new engines.
Cat is the real exception here because its October engines will be similar to
existing models until its real ’02 solution – ‘ACERT’, or Advanced Combustion
Emission Reduction Technology – is ready some time in 2003, said to be
starting in January. Come October of this year, Cat’s 3126E, C-10, C-12, and C-15 engines will be alone in using exhaust aftertreatment, but they won’t use EGR (note that the C-16 won’t be available at all until some later date).
Even though these so-called ‘bridge’ engines won’t meet the new emissions
standards (and Cat will pay fines as a result), there’s an advantage in there:
without EGR, they won’t require the new CI-4 oils. Nor will drain intervals change.
Depending on your operation, that may or may not make much difference.
So What’s CI-4?
Almost all major oil suppliers have announced new CI-4 oils to replace the present CH-4 versions, and in at least one case – ChevronTexaco’s Delo 400 Multigrade – an existing CH-4 lube is good enough to meet the new standards without
expensive testing and reformulation. That’s not a small deal if you have a mix of engines to lubricate, some with EGR and some without, because it could mean
sticking with your present lube oil.
The CI-4 designation, like all those that went before it, is the result of co-operative work by engine makers, the American Society of Testing and Materials (ASTM), the Society of Automotive Engineers (SAE), and the American Petroleum Institute (API).
Back in 1988, when the NOx limit was 10.7 grams per horsepower/hour (g/hp-hr),
we had CE oils. In 1990, when NOx limits were dropped to 6 grams, we had CF-4 lubes. Then in 1995 CG-4 oils came along when the NOx limit was set at 5 grams. In 1999 retarded engine timing was employed to drop NOx to 4 grams, but it also increased soot levels considerably, so CH-4 oils were developed. And
now, with NOx down to 2 g/hp-hr – but soot levels almost doubled – we’ll get CI-4, officially in September.
And when NOx is forced down to a mere 0.2 g/hp-hr in 2007 when the next round of emissions regs kicks in, we’ll need yet another class of oil. Not only will NOx
levels drop in 2007, but particulate emissions (mostly carbon) will be cut dramatically from their present 0.10 g/hp-hr to just 0.01. Work has already begun
on it, known as PC-10 (referring to ‘proposed category #10’), though engine
makers are nowhere near knowing how they’ll solve this daunting puzzle.
In order for an oil to earn the API ‘doughnut’ – the symbol that goes with a given
performance designation – it must pass certain rigorous tests, some developed
in concert with the engine makers themselves. The CE and CF-4 oils of the late 1980s had only four tests to pass, but that number has risen steadily as the demands on engine lubes increased. There were 12 CH-4 tests, and now there are 15 hoops for CI-4 oils to jump through.
The two principal CI-4 tests are the so-called Cummins M11 EGR and the Mack T-10 EGR tests. The former deals mainly with ring and valve-train wear as well as
filter pressure and sludge formations, while the latter focuses on ring, liner, and
bearing wear. Others include the Caterpillar 1R test, which looks at piston
deposits and oil consumption, and the Mack T-8E tests which examines an oil’s viscosity control when dealing with increased soot levels.
The tests are extreme. In the Cummins M11 EGR, for instance, the oil is first
conditioned in the engine by running with retarded timing and low coolant temperature. This process loads the oil with up to 5% soot before the wear cycle even starts. The test continues for 300 hours with soot levels increasing to 10%.
The test is designed to develop wear on rings and liner, as well as on the valve crosshead which is very susceptible to soot contamination. Also evaluated is the amount of sludge that builds up in the rocker cover.
Among the CI-4 lubes that have been announced so far, aside from ChevronTexaco’s Delo 400 Multigrade introduced back in 1998, are several reformulations: Petro-Canada’s premium Duron oil, Valvoline’s Premium Blue
Extreme synthetic, Mobil Delvac 1300 Super, Exxon XD-3 Extra, plus three new
products, Castrol Enduron S, Castrol Tection Extra and Castrol Tection S.
Remember that EGR engines absolutely need these CI-4 lubes, and will self-destruct without them. The good thing is that they’re backwards-compatible – meaning they can be used in older engines. They seem likely to cost more, though we have yet to hear how much, but they’re the best engine oils we’ve ever had.
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