Several manufacturers showed their new engines at the Fire Department Instructors Conference earlier this year, which has generated a lot of discussion among fire department personnel.

Not only are the engines new, but so are the cooling systems, exhaust after-treatment systems, fuel, oil and maintenance procedures. Although there are still some unanswered questions, one thing is sure — if it's driven by diesel, it's going to be different.

Manufacturer plans

To give you an idea of what's in store for apparatus buyers in 2007, here's a summary of the latest information from the major medium- and heavy-duty engine manufacturers.

Caterpillar will continue to use its proprietary ACERT technology for medium- and heavy-duty truck engines. The technology was introduced to meet the 2002 emissions changes and now has several million miles of proven service. It combines air management, precision combustion, advanced electronics and exhaust after-treatment to alter combustion performance and control the content of exhaust gases under a wide range of operating conditions.

To meet the lower 2007 emissions standard, Cat added a Clean Gas Induction system and a self-regenerating diesel particulate filter. The CGI system draws off a small amount of non-combustible gas after it passes through the exhaust after-treatment system, cools it, blends it with incoming air and returns the mixture to the cylinders, where it undergoes further combustion as part of the normal engine power cycle. According to Cat, CGI differs from the exhaust-gas recirculation systems used on some other engines because it recirculates clean exhaust gas, after it has passed through the after-treatment device, rather than untreated exhaust, which can contain high levels of soot.

The diesel particulate filter is designed to trap soot before it exits the exhaust pipe. Under conditions when the engine temperature is hot enough, this soot naturally oxidizes to form ash. When the engine temperature isn't hot enough, an automatic regeneration system injects a small amount of fuel into a closed combustion chamber, where it burns and raises the exhaust temperature. The fuel is not injected into the particulate filter or oxidation device in the exhaust system the way it is on some other engines, and Caterpillar says the process is completely safe and controllable.

The 2007 Cat engine line-up for fire service applications includes the C7, C9 and C13 inline, six-cylinder engines with several improved horsepower and torque ratings for better performance.

The C7 is a 7.2-liter engine that tips the scales at only 1,425 pounds of dry weight. Cat is expected to offer it in fire apparatus ratings of 300- to 350hp with peak torques of 860 foot-pounds. The light weight and good power make it an attractive choice for customers wanting to maximize vehicle payload.

The C9 has been given a larger 9.3-liter displacement to produce ratings of 365- to 425hp with peak torques of 1,250 to 1,350 foot-pounds. The new engine configuration has a dry weight of 1,650 pounds, which makes it about 1,000 pounds lighter than some other engines in this power range.

The C13 is a big 12.5-liter engine with ratings of 350- to 525hp and peak torques of 1,350 to 1,750 foot-pounds. It can be used where heavy vehicles or steep terrain are considerations. The C13 replaces the C11, which won't be offered in 2007.

To complement the new models, Caterpillar has a new engine brake and two new automatic transmissions. The Cat engine brake is a compression-type brake option that can be specified on the C9 and C13 engines. It meets the NFPA 1901 requirements for auxiliary brakes on apparatus with GVWR of 36,000 pounds or more. The Cat CX28 six-speed automatic transmission is now in production and may be specified with C7 and C9 engines up to 400hp and 1,250 foot-pounds of torque. The Cat CX31 six-speed automatic transmission is designed for larger engines up to 525hp and 1,770 foot-pounds of torque, including the C13.

Cummins customers can select their favorite model from the current engine line-up without any significant changes and only a few additional components. Cummins will continue to use exhaust-gas recirculation and variable geometry turbos as the basis of its emissions control system. For 2007, Cummins will add a diesel particulate filter, an enhanced high-pressure fuel system, crankcase ventilation and other features.

Cummins designed its own diesel particulate filter to maximize the effectiveness of the regeneration cycle. When regeneration is required, the system uses an oxidation catalyst combined with internal engine controls to allow regeneration under low ambient temperatures and low engine loads, as well as under higher temperatures and loads.

The ISB, ISC and ISL engines will use an enhanced high-pressure common rail fuel injector system. This system is designed to maintain a uniform high-injection pressure, regardless of engine speed, by storing high-pressure fuel in a single rail or tube that connects every fuel injector on the engine. It allows more complete combustion and provides a balance of performance, emission control and fuel economy across a broad engine operating range.

The 2007 Cummins engines for the fire service range from the ISB on the low end to the ISX on the high end. All are inline, six-cylinder engines that incorporate some new features.

The displacement of the ISB engine has been increased to 6.7 liters to give it more power for 2007. Fire service customers can specify ratings of 260- to 350hp with peak torques of 620 to 750 foot-pounds. The engine has a dry weight of only 1,150 pounds, which should make it attractive to weight-conscious buyers.

The ISC engine will be available with power ratings of 260- to 360hp and peak torques of 800 to 1,050 foot-pounds. This is a good medium-duty engine for customers who want more torque than the ISB.

The ISL engine should capture a lot of attention with power ratings of 345- to 425hp and peak torque figures of 1,150 to 1,250 foot-pounds. At 1,635-pound dry weight, it packs a lot of power into a lightweight package.

The big ISM engine is available in ratings of 365- to 500hp with peak torques of 1,350 to 1,550 foot-pounds. It's often specified for aerials and other higher GVWR apparatus.

Finally, the ISX gives maximum power and torque for the heaviest applications. Available in a 525hp rating with a peak torque of 1,650 foot-pounds, model comes standard with the Interbrake engine brake, which is capable of providing up to 600hp of braking force for severe operations in mountainous terrain.

Cummins also offers the C Brake by Jacobs as an option on the ISC, ISL and ISM models. This compression-type engine brake can provide the auxiliary braking required to meet NFPA 1901 for apparatus with GVWR of 36,000 pounds or more.

Detroit Diesel reaffirmed its commitment to continue production of the long-running Series 60 engine line for 2007. The engine will be based on the current design, which uses an exhaust-gas recirculation system. For 2007, Detroit Diesel has added several enhancements including an exhaust after-treatment system, improved turbocharger, new fuel-injection system, upgraded electronic controls and several other features.

The exhaust after-treatment system is probably one of the biggest changes. It consists of a diesel oxidation catalyst and a diesel particulate filter located in the exhaust system in place of the muffler. If soot builds up in the filter, a regeneration cycle is activated. During the 20-minute cycle, a small amount of fuel is injected into the oxidation catalyst to generate very high temperatures. The cycle interrupts if the engine compression brake is turned on, the vehicle slows to below 20mph or the vehicle stops.

The turbocharger will employ an electronic variable geometry design that automatically adjusts the boost across the operating range and delivers quick lift on the low end, where turbo lag would otherwise occur. The fuel-injection system includes dual solenoid electronic unit injectors that provide exact fuel metering and enable independent injection pressure control. The system also features a redesigned harness for more robust performance and greater accessibility.

Finally, the electronic control system has been entirely upgraded. The new system, known as DDEC VI, employs a more powerful microprocessor, increased memory capacity and enhanced diagnostics. A new version of the electronic pump-engine controls, known as Fire Commander II, will be compatible with the DDEC VI system.

Engines intended for fire service applications also will receive several special configurations, including unique component locations to provide clearances and special brackets to accommodate high-output alternators.

The displacement of all 2007 Series 60 engines will be 14.8 liters. Fire service customers can select engines with power ratings of 425- to 515hp and peak torques of 1,450 to 1,650 foot-pounds. The Series 60 has been popular with customers who want big power from a big block, and it appears the 2007 version will continue to find such buyers.

International will be selling all on-highway engines, including both medium- and heavy-duty models, under the name Maxx-Force for the 2007 models and beyond. In addition, International plans to use exhaust-gas recirculation and use several other technologies to meet the 2007 emission requirements.

Like some other manufacturers, International will have an oxidation catalyst and particulate filter in the exhaust system. On medium-duty models, the two components will be separate to keep the oxidation catalyst close to the engine and allow mounting flexibility for the filter. On heavy-duty models, the catalyst and filter will be mounted in the same housing.

International's 2007 medium-duty engine line will include new versions of the current 7.6-liter DT 466 and 9.3-liter DT 570. The DT 530 will be dropped. Power and torque ratings are expected to be similar to current engines.

In late 2007, International plans to introduce a new line of heavy-duty engines that include 11- and 13-liter models. Announcements of specific ratings and other details are expected to be released next year.

Mercedes-Benz medium-duty MBE 900 engines will be available only in Freightliner M2 chassis starting in 2007. Like other 2007-certified engines, the MBE 900 will require a diesel particulate filter that will replace the muffler in the exhaust system. No other significant hardware changes are planned. Fire service ratings include 190-350hp with peak torques up to 860 foot-pounds.

Emissions down, prices up

All of these changes carry a price tag, and customers should plan on paying more for trucks with 2007 engines. Not only will the engines cost more, but all the related changes to the cooling and exhaust systems will add up as well.

For apparatus built on commercial chassis, International is on record as saying its medium-duty truck models will probably cost $3,000 to $5,000 more. Freightliner announced it expects prices to increase by $4,500 to $6,000 on its medium-duty trucks, and by $7,000 to $10,000 on its heavy-duty trucks. Peterbilt estimates that the price of its medium-duty trucks will increase by $2,000 to $4,000, while its heavy-duty trucks will increase by $6,000 to $9,000. Other manufacturers haven't released estimates yet, but the range of potential price increases is clear. Apparatus built on custom chassis probably will be close to the figures for heavy-duty trucks. Customers should add an appropriate amount to any budgets for apparatus purchased in 2007 and beyond.

Other effects of the 2007 engines include more weight and different fuel, oil and maintenance requirements. (See “New Engines Need New Maintenance” on page 72.)

With any major product introduction, changes often happen right up to the last minute. Customers should check with their local dealers to confirm engine availability, ratings, configurations and pricing.

New Engines Need New Maintenance

Departments that purchase apparatus with one of the 2007 engines will be faced with a number of new maintenance procedures and considerations.

Training

Most engine manufacturers are already training their service personnel. If you perform your own engine maintenance, you need to contact your local dealership or distributor about training opportunities and any new diagnostic tools and procedures.

Fuel

All 2007 diesel engines will require ultra-low sulfur diesel fuel to operate properly and meet emission requirements. This is mandatory, not optional. Using the current low sulfur diesel in 2007 engines will violate federal law and invalidate the engine warranty, and may damage the engines and related systems. All fuel dispensing pumps will have warning labels to inform drivers of this requirement.

Departments that store and dispense their own diesel fuel need to understand that residual levels of sulfur from the current fuel can contaminate ULSD and raise the sulfur level. It may take several tankloads to flush out the extra sulfur. The new fuel can be used on older vehicles, but it may cause fuel system leaks or premature fuel filter plugging. Departments should monitor their pre-2007 vehicles during the changeover.

Oil

The 2007 engines also will require new engine oil, but the specifications may vary from one manufacturer to another. Right now, it appears that the new CJ-4 oils will replace the current CI-4 and CI-4 Plus formulations for the new engines. The CJ-4 oils are backward-compatible, but they may be somewhat more expensive. Some oil companies have already announced that they will continue to sell both CI-4 and CJ-4 oils.

Particulate filter regeneration

One of the new components found on all 2007 engines will be a diesel particulate filter. When the engine is operating at high temperatures for sustained periods, the filter will work without assistance. When the engine is operating at lower temperatures for shorter periods, the filter will need regeneration. This process is automatic and takes about 20 minutes of continuous operation at moderate speeds on some engines. If that isn't possible, the regeneration process may have to be actuated manually by the driver or a service technician while the vehicle is in the station or shop. Departments need to ask the engine manufacturer about this requirement.

Particulate filter cleaning

In addition to the regeneration process, the particulate filter must also be cleaned periodically. The recommended service interval is 150,000 to 400,000 miles, depending on the engine and vehicle application. Most engines will need to have the filter removed from the vehicle to do this. Cat filters can be cleaned in place. All particulate filters require special cleaning tools, and the procedure is probably best done at an authorized service facility.

Push to Gas?

In the June 2006 issue of Fleet Owner, Ross Hendrix, marketing director for General Motors Fleet and Commercial unit, said the 2007 changes to diesel engines may make gasoline engines more attractive to some medium-duty truck customers.

He noted that higher engine and fuel prices may eliminate the advantages of diesel engines for customers with lighter payloads and lower annual mileage. Hendrix said that current gasoline engines have roughly the same fuel economy as equivalent diesels, and the maintenance is about the same. He expects customers will see even more advantages of gasoline engines in 2010 when diesels have to comply with new, and even tougher, emission requirements.

GM offers its Vortec 8100 MD gasoline engine with power ratings of 295-325hp and peak torques of 440-450 foot-pounds. According to GM, this engine provides good power for vehicles that are primarily engaged in stop-and-go, in-city driving with less than 25,000 miles per year.