Are You Ready For January '07 Engines?

Sept. 28, 2010


Most '07 diesels, like this Cat C15, will drive as well as or better than current models. Fuel economy should stay the same or be better, but ultra low-sulfur fuel will cost more and have lower energy content.
Special machines like this will clean diesel particulate filters with compressed air. Most dealers will have them, and will also offer clean filters on an exchange basis. Caterpillar DPFs can be cleaned while still on trucks.
Volvo and Mack will use a squat "compact" DPF placed under cabs or behind the right-front wheel of some trucks. On other trucks, the devices will be in exhaust stacks.
New engines need ultra low-sulfur fuel, so current higher-sulfur fuel should not be put in the new trucks' tanks.
A Hot Time

All builders' DPF regeneration will occur automatically. It will be passive when exhaust heat in the device climbs above 450 to 570 degrees Fahrenheit, or active, with minute injections of fuel, if temperatures in the DPF consistently remain too cool.

Heat inside DPFs and at tailpipes will get quite high — 1,000 to 1,200 F. But aftertreatment devices will be dual-walled to insulate their outer skins from heat. Their "touch temperatures" will remain about like they are now, or around 500 F. That's hot enough to smart if someone touches it, but not enough to burn flesh unless he hangs on. Also, aftertreatment devices will be mounted like mufflers, under the truck or on the exhaust stack, where people aren't likely to come in contact with it.

Tailpipe temps sound high, but manufacturers note that they will be about what current gasoline engines produce. And heat dissipates fast when the exhaust hits the outside air. Even so, some builders are talking about adding diffusers at the end of exhaust pipes to be on the safe side.

Regenerative heat could radiate off a truck that's parked near pedestrians or in tall grass, causing discomfort or fires. So most builders plan to lock out active regeneration unless the truck is moving 10 mph or faster, with the actual speed varying among builders. Some trucks will have a switch in the cab to allow drivers or technicians to start a regen if needed, or stop one if it might be dangerous. A dash light would signal when a regen is about to occur or when it is in progress.

Temperatures at tail pipes could exceed 1,000 degrees F, but measurements show that the heat dissipates fast when the exhaust hits the outside air.
PCVs and Oil Drains

Positive crankcase ventilation systems will be part of 2007 diesel engines, and they will have their own filters. Some will need periodic, though infrequent, cleaning, which might be done every third or fourth oil change. Others will need no maintenance. As with exhaust-gas recirculation systems, hardware in the PCV system should be looked at regularly to ensure integrity and proper operation. A plugged EGR valve can shut down a diesel and puzzle its driver unless he knows what it is and sees that it gets cleaned out.

Oil-drain intervals will in most cases be the same as for current engine models, according to the builders, who've gone to great pains to ensure this aspect of performance. This is due to low-sulfur diesel fuel and low-ash CJ-4 motor oil, which will help keep engines and the oil itself clean. And a few engines will have larger sumps or oil pans to lengthen intervals.

In this story:

Brace yourself for January 1st. That's when the federal government's latest round of diesel exhaust-emissions regulations take effect and, as you've probably read or heard, they'll result in new, heavier engine equipment and substantially higher prices. That reality has generated a storm of orders, especially from freight haulers for whom trucks are a major part of doing business. Many big fleets are stocking up on current models to avoid looming price hikes and added complexity. Heavy-truck manufacturers are sold out through the end of the year.

The "pre-buy" is also being pushed by a healthy economy and high freight tonnage, which requires fresh trucks to move things. The situation mirrors the runup to the October '02 deadline and, as happened then, a sales slump is expected to follow the frenzy. Many buyers will hang back to see how the new trucks and engines behave, then slowly return to the market.

Other users, including some in the construction segment, are more sanguine because trucks are among many expensive tools in their equipment fleets. Manufacturers say that most vocational buyers are becoming aware of the upcoming changes, and seem resigned to face the realities of greater complexity and higher price when they arrive. Or they'll hang onto the trucks they have now for a while longer.

Clean Air advocates should celebrate the vehicles that will comprise the latter part of the '07 model year. Diesels will burn cleaner than ever, emitting only half the oxides of nitrogen (NOx) and one-tenth the particulate matter (PM) of current diesels. This arguably is a substantial societal benefit, though most users wince at its cost.

A diesel-powered light truck is expected to run $1,500 to $2,500 more than now; a medium-duty truck will cost $3,500 to $7,000 more, and a heavy truck will list at $6,000 to $10,000 higher, according to builders who have announced pricing. Buyer resistance and competition might cause those numbers to fall somewhat, especially if orders for new trucks fall off by 30 to 40 percent, as some predict.

Once in buyers' hands, the new diesels will need special care. They'll run hotter, putting more load on trucks' cooling systems, some of which have been beefed up to handle the extra heat. New exhaust filters will periodically heat up to burn off accumulated soot. Engines will burn ultra low-sulfur fuel that is just now becoming available, and is expected to cost more than present fuel. They'll use a newly formulated low-ash motor oil that may also cost more. Eventually the diesels will require new maintenance procedures, which will take some extra time and know-how.

On the other hand, the 2007 engines will drive as well and maybe better than now, and should use no more fuel than current diesels, and in some cases less. Previous changes in emissions regulations have sometimes meant worse fuel economy. So holding the line is not an insignificant accomplishment for the engine makers who have labored long and hard to meet the upcoming limits, and truck builders, who have spent hundreds of millions of dollars to engineer the new diesels into their chassis. Then again, the new fuel will have a bit less energy content, which could degrade measured tank mileage, and there are questions about its lubrication properties.

Some manufacturers have used the challenge to make major updates to certain models. Some trucks will look different and be nicer to drive, and some are getting new names. We cover many of the changes and updates in our roundup on following pages.

Exhaust aftertreatment

Most '07 engines will exhale through an exhaust system equipped with an oxygen catalyst and a diesel particulate filter, or DPF. The catalyst will chemically change certain pollutants into non-harmful substances, leaving water and carbon dioxide (CO2 is not toxic, even if it is a greenhouse gas blamed for Global Warming). The DPF will trap particulates, or soot, which will periodically burn off. But ash from motor oil will collect in the DPF and must be removed through special cleaning.

Exhaust heat from high-load highway operations will be enough to burn off soot in a process called passive regeneration, engineers explain. In stop-and-go operations, including what's seen by many construction trucks, extra heat will be needed for what's called active regeneration. This comes from injecting small amounts of fuel into the exhaust stream; when the fuel hits the oxygen catalyst, a reaction causes high heat, which then passes into the DPF and burns off the accumulated particulates.

That generally describes the systems to be used by Cummins, Detroit Diesel (including Mercedes-Benz), General Motors-Isuzu, International (and Ford), Mack and Volvo. The imports — Hino, Isuzu, Mitsubishi Fuso and Nissan UD — are already using such systems in Japan. They will bring them to North America come January. As now, the systems will use exhaust-gas recirculation (EGR), but higher doses of it, to lower cylinder temperatures and reduce formation of NOx.

Caterpillar is taking a different approach for '07. It will begin using cooled exhaust-gas recirculation, which it has pointedly avoided since October '02. But Cat's EGR will use filtered exhaust gas taken from the end of the aftertreatment device, not raw gas straight from the exhaust manifold as other builders do. In what's called Clean Gas Induction, a pipe carries gas from the rear of the aftertreatment device to the charge-air cooler. Cat claims its system will let engines stay cleaner inside and therefore last longer.

Cat's '07 aftertreatment will have a DPF, but not an oxygen catalyst. The system injects fuel behind the turbocharger and electrically ignites it, sending flame into the DPF; this burns out accumulated soot. As now, Cat will initially clean exhaust gasses with ACERT equipment, including double turbo chargers on larger models. Cat and other builders will also upgrade fuel-delivery systems and electronic controls; the latter will get more powerful microprocessors and more capable software. All builders' aftertreatment devices will resemble mufflers and actually muffle combustion noise, so mufflers as such will no longer be used.

Operation and maintenance

Most engine models will run like current ones, though some will run a little slower, and operating rpm might be tighter. So gearing — choosing ratios in transmissions and drive axles — will be even more important than now. Engine makers will disseminate information on proper spec'ing, which dealers should have. But manufacturers encourage sales people and fleet managers to consult with factory experts if there are any questions about specifications.

Diesels will burn ultra low-sulfur fuel, which refiners have just begun producing, to keep the catalyst and DPF from clogging. Use of higher-sulfur fuel won't necessarily kill the filters, which are made of ceramics and precious metals. But the extra sulfur will hamper their work and soon plug them, requiring premature cleaning or replacement. So, although there's controversy over the new fuel's distribution and storage problems and possible lubricity issues, owners and drivers should be sure that it's the only fuel that goes into tanks.

Crankcases will be filled with a new, low-ash oil, called CJ-4. Manufacturers say that the new oil, like the fuel, is necessary to protect the exhaust system's DPF. Shops will have to stock up on CJ-4 and for a while, at least, continue using current CI-4 motor oil for older engines. Like previous formulations, CJ-4 will be backwards-compatible, which means it can be used in older engines. But the current type, CI-4, is a better choice for them, as long as it's available.

Filter cleaning

Cleaning ash out of the DPFs will become a new service procedure. In most cases, cleaning will be done by removing the DPF element from the truck — an easy job, partly because parts will be made of stainless steel to resist corrosion, manufacturers say — and placing it on a special machine (though Cat's DPF will come with connections that will allow attaching hoses to clean it right on the chassis).

The console-like machine will blow compressed air at normal shop pressure (about 90 psi) through the filter in pulses; this will take about a half hour, during which the technician can perform other service work on the truck. Removal and reinstallation of the DPF will together consume another half hour and maybe less. Most builders will offer clean DPF elements on an exchange basis, but dealers will probably obtain the simpler and less costly air machines.

Detroit Diesel (which markets and supports M-B diesels) will recommend filter cleaning with deionized water. This will be done on larger, more complex machines at Detroit's remanufacturing centers. In that case, an exchange program will use cleaned filters with dirty filters turned in for core value. Detroit will also allow the air-cleaning method, but says it doesn't work as well as the fluid. A brand-new DPF element, if it's ever needed, will cost hundreds of dollars.

Servicing DPFs won't be needed often, and owners won't have to deal with them until trucks have been run a while. EPA regs require at least 150,000 miles of use on a heavy-duty diesel before the first service is required. Engine makers say it might be required at intervals of 200,000 to 300,000 miles for long-haul tractors. Vehicles run in cities, including construction trucks, will require servicing more often, though relatively low annual mileages will stretch out the intervals in terms of time.

Exhaust configurations

Combined catalyst-DPF devices (or just the DPF in Cat's case), which some truck builders call "cans," look like big mufflers but weigh more — 80 pounds or so — manufacturers say. That includes 50 to 60 pounds for the DPF element. They'll usually be mounted under cabs or in vertical stacks. Cans on stacks might need special lifting devices, and those in other under-cab locations might require a creeper and a transmission jack to get to and handle.

Multi-axle dump trucks are the toughest vehicles on which to "package" the cans because pusher axles take up space on the frame. Vertical stacks are the likely solution and, in some cases, the front corners of bodies may need sculpting to make room for the bulky equipment. Asphalt-hauling bodies needing exhaust heat will have to take exhaust gasses from downstream of the DPF, so under-cab fitment is likely for them. The longer the chassis and wheelbase, the easier it will be to accommodate the aftertreatment parts.

Some light trucks will have a split aftertreatment system, with the oxygen catalyst close to the engine and the DPF farther downstream. Although those two parts will muffle most noise, there'll also be a resonator to take out droning at certain engine speeds.

The resonator, slightly smaller in most cases than a present-day muffler, will be ahead of the rear axle of a pickup-type truck or crossways at the very rear of a cargo van. These systems will be hung on vehicle frames, so should present no difficulty except where power take-offs are used. Then access to transmissions might be limited.

Midrange trucks are more complicated. Because they are fitted with a wide variety of bodies and equipment, manufacturers will have to use a split system, as on light trucks (except for Cat's DPF-only device). But more often they'll be a single-unit can, as on heavies. Usually the can will go beneath the cab, off to the right. In some cases it will be under the steps on the curb side. The tail pipe will run rearward on the frame or up a rear corner on the cab.

Aftertreatment cans will be wired into engines' electronic control modules, which will monitor the devices' condition and order active regenerations if needed. ECMs will lower horsepower and torque if catalysts or elements get plugged, and even shut down engines in dire cases. Tampering with or removing aftertreatment devices will cause ECMs to disable engines. Technicians will thus have to learn how these circuits work and how to troubleshoot and repair them.

Exhaust systems will be "no-touch" items that may not be changed because they will be certified by manufacturers. Dealers and upfitters, who sometimes cut into and alter exhaust systems to make room for installation of special bodies and equipment, must leave the '07s alone. The only thing they can change on an '07 is the tailpipe, manufacturers say. Dual exhausts will disappear from all but high-horsepower diesels, and straight pipes will be illegal because the aftertreatment devices must remain on the trucks.

Dealers who stock bare chassis and alter them for specific applications might have to plan ahead more. Builders say they'll offer several exhaust configurations for each truck model, and the correct one for the job will have to be spec'd in the order. Manufacturers are not likely to offer kits to change exhaust configurations because that would put dealers or upfitters in the position of certifying exhaust emissions performance — something neither they nor the federal Environmental Protection Agency would want.

Training underway

Engine and truck builders say they've begun training dealer technicians on the new systems. Cat, for example, is trying to eliminate the "fear factor" inherent with new and unknown equipment by producing educational sessions on the Net and CDs, and in its closed-circuit TV broadcasts. All builders have begun printing special literature and training materials, and are preparing to put special tools in dealers' hands.

They say they've also tried to minimize the number of tools needed for servicing. The compressed-air cleaning machine, for example, is a generic design usable for all DPFs. One model is built by tool maker SPX, a name familiar to shop people. It runs on 110-volt power and standard shop air, sits on rollers so it can be moved among service bays, and costs several thousand dollars. Only large truck fleets are expected to buy these machines, as most operators will let dealers handle this specialized maintenance.

Wait 'til 2010

If you think these changes are major, wait until 2010, say the manufacturers. Even stricter diesel emissions limits are scheduled for then, and will require more equipment and more money. The most likely aftertreatment system will inject an additive into the exhaust stream to further cleanse it of pollutants. Such systems are now working on diesels in Europe. Stay tuned.