Chapter 5 -
Component and system considerations

In today’s competitive transportation environment, trucking companies want more from their fleets: improved performance, lower maintenance, extended lubrication intervals, longer life, greater fuel economy and reduced life-cycle cost.

One worry is the shortage of good, experienced technicians. If a component fails today, the downtime may be longer than in the past, because a technician may not have the time to devote to getting the truck back on the road. There simply is less manpower available to repair vehicles.

Additionally, truck operators — in concert with truck manufacturers and component suppliers — have become more knowledgeable about spec’ing their vehicles. They look at buying a new truck as an investment and select components that are most economical over the life of the vehicle, while providing the best resale value.

The need for better equipment is even more important when you consider the truck operator. With the shortage of experienced drivers, fleet managers are trying to put together the most attractive packages to attract and retain drivers. More and more trucks are being spec’ed with a variety of driver amenities, from spacious, comfortable cabs to high-quality seats and automatic transmissions.

Truck and component manufacturers are responding to these demands with increasingly sophisticated offerings tailored to meet your needs. The 500,000-mile vehicle target has already been surpassed, with some components at the 1-million-mile mark and others not far behind. Because modern vehicles are increasingly complex and technologically advanced, all the parts, though manufactured by many suppliers, must work together as a complementary system.

In an effort to optimize performance, truck components are “talking” to one another as never before, working as a complete system to unlock new performance improvements.

Truck equipment technology is advancing rapidly, and staying abreast of the changes can be overwhelming. The good news for fleet managers is that many new options are tailored to meet their demands. The improvements do not stop with the hardware; suppliers are supporting their products as never before with an impressive range of services, including training and extended warranties. Understanding the evolving world of equipment technology is a key element in running a safe and efficient fleet.

Engines
The emergence of high-torque/low-rpm electronic diesel engines has been key for many new technologies. Most of the advances in power plants have been sparked by federal, state and local mandates to reduce emissions. Electronics help make that happen. Additional benefits of these new electronic engines include increased fuel efficiency, improved service life and higher resale value.

Before the advent of fuel economy standards, diesel engines mechanically timed their combustion process with one rpm range set for complete combustion and minimum emissions. Above and below that range, the emissions generated smoke —- or unburned fuel.

Today, electronic control units (ECUs) govern the diesel combustion process, timing the fuel injection to reduce emissions. The advantage is that the ECU can be adjusted for increased or decreased power and economy and can provide a host of vehicle-specific maintenance information. A network of sensors used by electronic engines monitor specific engine and powertrain parameters. The network includes connections from the instrument panel to sensors monitoring oil temperature and pressure, coolant level and temperature, intake manifold air temperature, injection pump performance, rpm and timing. Information from these sensors allows adjustment for variable engine loads and programmable engine performance. Electronic systems can alert the operator to specific problems.

Engineers are struggling with a variety of technologies to meet stricter emissions requirements, and the issue for fleets is to determine what those various solutions mean in terms of cost, efficiency, durability and overall operating characteristics.

In general terms, the Environmental Protection Agency is concerned about two components of diesel emissions: particulates, which are solids created by unburned fuel and byproducts; and oxides of nitrogen, which are called NOx, and are linked to ozone-layer damage. Over the past decade, EPA requirements have largely addressed particulate emissions - which, according to the Engine Manufacturers Association, are now 90 percent below levels commonly seen in 1987.

EPA’s next major emissions campaign was to slash NOx emissions. By the late 1990s, NOx was already 70 percent 1987 levels, but EPA adopted regulations establishing further reductions in 2004 and 2007. But given the imperative to reduce particulates, further cuts in NOx are very difficult without hurting fuel economy. In a nutshell, particulates, NOx and fuel consumption form a tripod. Reducing one usually increases the other two. Lowering combustion temperatures in the cylinder, for example, cuts NOx but boosts particulates and may have a negative effect on fuel consumption.

As if the 2004 and 2007 dates weren’t difficult enough to meet in this context, EPA accelerated the schedule in 1998 when it forced suppliers of heavy-duty diesel engines to accept a settlement of charges the agency had leveled against them regarding on-highway emissions. Among other things, the Jan. 1, 2004, emissions deadline moved up to Oct. 1, 2002.

To meet that deadline, four engine suppliers — Cummins, Detroit Diesel, Volvoand Mack — developed solutions based fundamentally on a technology called cooled exhaust-gas recirculation, or EGR. EGR systems reduce combustion temperatures by mixing cooled exhaust gas with intake air charge, cutting NOx by up to 50 percent with minimal impact on fuel efficiency.

But as indicated above, an increase in particulate emissions is a consequence, requiring improvements in engine lubrication to handle soot. (See the discussion of lubrications later in this chapter.) And cooling the exhaust required greater heat-exchange capacity and changes in engine compartments to accommodate that greater capacity.

Caterpillar chose a different course for complying with the EPA mandate, opting instead to develop Advanced Combustion Emissions Reduction Technology, or ACERT. ACERT represents a combination of an intelligent version of Cat’s hydraulic-electronic unit injection (HEUI) system to minimize emissions in the cylinder with an oxidizing catalytic converter to polish off particulates and hydrocarbons. Cat was unable to certify ACERT engines to EPA’s strict standards by Oct. 1, 2002, but rolled it out gradually in engines produced during 2003.

Engine makers quickly turned their attention to meeting the 2007 emissions deadline. Some potential solutions require ultra-low sulfur fuel, and EPA is requiring petroleum refiners to phase in such fuel beginning in 2006. Still, the 2007 mandate is quite challenging, and a clear solution has yet to emerge. Solutions based on EGR technology likely will include at least two advances:

• Particulate matter traps. These devices, which resemble mufflers, extract approximately 90 percent of exhaust soot via a ceramic or metal lic filter that’s continuously or periodically purged and regenerated through incinerating soot. Ash may
  accumulate within a trap and require periodic removal.
• NOx adsorber. This device collects the offending pollutant on the outside of its internal element (as opposed to an absorber).

An alternative to EGR is selective catalytic reduction. SCR uses ammonia provided by introducing a urea/water mixture from a vehicle-mounted tank into the exhaust, upstream of a catalyst.

SCR systems reportedly can reduce NOx by 70 to 90 percent, while allowing for an engine calibration with 15 percent better fuel economy and good levels of power and torque. However, there are concerns, such as additional tanks, frequent replenishing of urea, and the urea/water mixture freezing.

SCR is the probable European emissions solution moving forward, which would make its use advantageous to engine suppliers — such as Detroit Diesel/Mercedes Benz and Volvo/Mack — that are owned by European engine makers. Due to the infrastructure requirements and other concerns — including EPA resistance to the technology — SCR seems to be a long-shot as a solution to the 2007 requirement in the United States.

Transmissions
Converting the power produced by the engine to the wheels is the job of the transmission. The past 10 years have seen a revolution in the design and operation of commercial truck transmissions, as well as an expansion in the options available to truck buyers — options that might cause many buyers to scratch their heads in confusion. Currently, you can choose from among more than 120 models of medium- and heavy-duty transmissions.

Transmission suppliers are not trying to make drivetrain decisions more difficult; they are working to better tune the performance and behavior of the transmission to the specific needs of its operator. As horsepower and torque have increased, the torque capacities of transmissions have increased to as much as 2,250 lb-ft — and they are not done yet. New transmission designs and the application of electronics and automation promise further longevity, reliability, efficiency and driver ease.

For many years, the mechanical transmission was the gear box of choice, with nine-speed range-type transmissions ruling the road. A typical high-performance or vocational spec included a 13-speed, an eight-speed “LL” or a 15-speed. Then new engine-performance parameters shifted that conventional wisdom. Today, the typical demands are 10-speeds with tighter ratios for a standard fleet spec and 18-speeds to answer a real (or perceived) need for more ratios, more performance, more versatility and more power.

A new type of transmission emerged in the late 1980s, using a combination of splitter and range shifts, and a unique back-box gear arrangement. Dubbed a low-inertia design, this transmission provided smoother, faster shifts; improved performance and enhanced driver ease. The concept was introduced in 18-speed transmissions, migrated to 13-speeds and was extended into 10-speeds.

Most recently, transmission manufacturers have refined their time-proven products — sometimes reinventing them entirely — to provide extended life, longer intervals between maintenance and overhaul, lighter weight and quicker shifts. These refinements have led to automation. One unique aspect of the low-inertia transmissions was that the two top gears were simply a button-actuated splitter-shift away from one another. That design made it relatively easy, with a little bit of hardware and electronic communication from the engine, for electronics to perform those shifts, depending on the demands of the load or road. Because 90 percent of line-haul truck operation occurs in those top two gears, automatically shifting between the top two gears could provide hands-off highway shifting and a fuel-economy improvement of between 1/10 and 4/10 of a mile per gallon.

But automation provided more than improved fuel economy. It promised a more durable drivetrain, because it took the potential for abusive shifting away from the driver. It promised improved performance, with every shift completed at the optimal moment. It promised driver ease, as well as the potential for every driver in the fleet to shift as well as the best driver in the fleet. And it contributed to safety, allowing drivers to pay less attention to shifting and more to the road. It was only a matter of time before the promise of automation was extended to every gear in the transmission.

The easiest, and most economical, road to a fully automated transmission adds an ECU and a shift-actuator mechanism to a proven, reliable mechanical transmission. With the engine ECU and transmission ECU communicating through a high-speed data link, the stage was set for fully-automated shifting, from full-stop to full-out and back again. Several types of automation are available in today’s transmissions:

• Top-gear automation, which automatically shifts the transmission back and forth between the top two gears.
• Assisted shifting, which automates synchronization and eliminates clutching. This technology is headed toward full shift-by-wire function, in which the operator merely moves a toggle or joystick to shift the transmission while retaining shift-point control.
• Partially automated, which requires clutching to start and stop the truck, but the engine and transmission determine the shift points on their own.
• Fully automated, which by various means provide fully automatic shifting without a clutch pedal. Clutching is provided by means of electropneumatics.
• Fully automatic, which is fundamentally the same as fully automated, but a fluid-filled torque converter replaces the clutch.

Transmission suppliers are in a fierce competition to provide the next advancement in transmission technology, a situation that will benefit fleet owners and managers. High-speed data-link systems soon will extend throughout the truck, enabling all the electronic systems to communicate. An automatic transmission, for example, will be able to talk with the antilock braking system and traction-control system for safer acceleration and deceleration on slippery surfaces. The data links also provide diagnostic capabilities that will make servicing the powertrain components easier and faster. Include onboard communications capability, and the truck will be able to diagnose itself and call ahead to a service facility, telling the technician exactly what needs to be done and what parts are needed before the truck rolls into the bay.

The new transmission ECUs also are highly adaptable to new duty cycles and vocations. A line-haul tractor can be converted for inter-city delivery simply by downloading new data to the ECU over the Internet.

Although the cost of full automation of Class 8 trucks has been prohibitive, manufacturers are now offering products that provide most or all of the benefits of traditional automatics at a very reasonable up-charge from a standard mechanical gear box.

The medium-duty market is eager for automation, with more than 50 percent of Class 6 and 7 trucks now running some kind of automatic. Fleet owners continue to look for easier-to-shift transmissions. Fleet operators and drivers say they want transmissions that increase driver comfort and make the driving experience easier and safer. For that reason, engine and drivetrain manufacturers will continue to work together to add efficiencies and performance improvements through optimization of powertrain component performance, closer matching and, possibly, electronics integration.

Suspensions
When it comes to truck suspensions, fleets are looking for a good ride for the driver and cargo. And, of course, they want this enhanced performance with reduced weight, low to no maintenance and a lower price tag. Fleets can achieve these objectives in several ways:

• Air-ride. A total air-ride package is desirable for long-haul, over-the-road applications.
• Four-spring. Four-spring suspensions are designed for shorter-haul highway work in cost-sensitive operations.
• Air leaf. Recommended for on-highway service, this system uses air bags with tapered leaf springs and is intended for dump trucks, wreckers, lube trucks and similar service vehicles.
• Low air leaf. This type of suspension is intended for general freight, tankers, refrigerated carriers and other operations in which a low frame height is desirable.
• Taper leaf spring. This spring suspension is designed for agricultural, on-highway refuse, lumber, tankers, logging and livestock applications.
• Multi-leaf spring. This type of suspension is used for normal over-the-road applications.
• Rubber load cushion. This suspension is intended for vocational operations in on- or off-highway applications.
• Solid mount. Solid-mount suspensions are designed for severe-service on- or off-highway operation in refuse, ready-mix and logging applications. Multi-leaf, rubber-load cushion and solid mount type suspensions may be of the walking beam variety where the front and rear axles in a tandem pivot and move up and down in opposite cycles.

Several factors are involved in making the proper suspension decision, especially given the wide range of wheelbase and frame-rail offerings. Although air-ride suspensions account for nearly 60 percent of the heavy-duty vehicles on the road today, almost all the new units rolling off the assembly lines are equipped with air suspension.Use of the product is increasing in vocational and medium-duty applications — especially those that involve limited off-road use — for driver retention and cargo protection.
When you choose a suspension, consider the following:

• Road use. On what type of roads will the vehicle be operating? Air suspensions are designed primarily for over-the-road applications because they help improve driver comfort and dampen rough roads.
• Loading. All suspensions are designed for a rated load. Exceeding these limits produces increased wear and premature failure. Suspensions are also rated on the gross combination weight (GCW) of the vehicle; that rating should not be exceeded.
• Type of service. A major consideration is the load’s center of gravity. A cement mixer does not weigh any more than a dump truck, but its center of gravity is higher. If that center of gravity gets outside the base of the suspension when the vehicle goes around a curve, the vehicle will be less stable. So the amount of weight does not always dictate the type of suspension, but where the weight is located sometimes does. That is why different suspensions are “stiffer” than others. The challenge is to provide a smooth ride when the vehicles are empty.
• Compatibility. Under normal circumstances, the suspension and the axle should be closely matched in load rating. The perception remains, however, that in certain applications, one component should be higher in rating than the other.
• Articulation. In over-the-road applications and some smoother-surfaced off-road venues, such as gravel roads in logging operations, articulation — the up and down range of movement of the axles — is not a problem. But when units operate in more severe-duty applications, highly articulated mechanical suspensions help keep all wheels on the ground and turning.
• Operations. Each suspension has a specified ride height. An improperly adjusted ride height can lead to costly driveline repairs. Additionally, proper alignment with the rear axle is essential to
  performance and tire wear.
• Maintenance. Tractors with air-ride suspensions are less expensive to maintain, because they dampen the jostling and road vibration that literally shake components into premature failure.
• Residual value. Air-ride suspensions on twin-screw tractors add about $4,000 to the resale value of a used heavy-duty tractor, according to National Market Reports, publisher of the Truck Blue Book. A single drive axle adds approximately half that amount — not a bad return on a component that typically represents an up-charge of $1,200.

Brakes
Brakes are mechanical devices that use friction to retard the motion of a vehicle. Friction is the resistance to relative motion between any two bodies in contact, and it varies not only with different materials, but also with the condition of the materials. Where there’s friction, there’s heat. When a driver applies the brakes, the energy of motion is changed into heat energy, which the brakes must dissipate or absorb. How efficient a truck’s braking system is depends on vehicle aerodynamics; highway or road conditions; axle differences; and the vehicle’s speed, weight, weight distribution and size.

The foundation brake is the actual braking mechanism located at each end of the axle. It generally consists of the air or spring actuator, the slack adjuster or wedge assembly, the mechanical brake mechanism (including the brake shoes and the attached friction material) and the brake drum.

The most popular type of foundation brake is the cam type. In an air-brake system, the air compressor takes free air and compresses it to 100 to 120 psi. The air passes from the compressor into the reservoir, where it is stored until the driver releases it when stopping. At that point, air flows to the chambers, where this energy is transferred into the mechanical force and motion, literally twisting the S-shape cam and forcing the brake lining into contact with the brake drum. This creates the friction necessary to stop the vehicle. Automatic slack adjusters help keep the brake travel, or twisting force, of the S-cam consistently adjusted.

Antilock braking systems (ABS), now required in all heavy- and medium-duty applications, are designed to provide improved vehicle stability by reducing wheel lock during aggressive braking. Sensors at the wheel end identify when a wheel lockup occurs and automatically cycle the brakes on and off to control lockup and skidding.

Electronic braking systems (EBS) are about to make their North American debut. The so-called brake-by-wire technology, which is commonplace in European trucking operations, has yet to gain much traction in the United States. Still in its early stages, EBS technology is considered to be the next advance in heavy-duty braking, and will provide fleets important advantages in brake balance, stability and control.

Instead of air, electronic braking uses electronic impulses to quickly actuate relay valves, which send actuation air to nearby brake chambers. Other than the signal, brake components remain the same: compressors, air dryers, air reservoirs, foundation brakes, slack adjusters and brake chambers. EBS will not replace antilock and automatic traction control; rather, it will be integrated as a critical part of the braking system.

Here is how EBS works: when a driver hits the brakes, a signal travels from the brake-pedal transmitter to the EBS electronic control unit. Sensors then measure braking-system parameters (such as axle load, wheel speed and lining wear), and the system provides controlled braking pressure to each wheel or axle of the tractor and trailer. All this happens in a fraction of a second. Drivers get instant response instead of waiting for the compressed signal air to weave its way through the serpentine hoses. In addition, EBS can detect brake fade and notify drivers if wear levels become critical. Drivers’ control of braking is more predictable, regardless of equipment loads, thereby shortening stopping distances and improving vehicle stability.

If a malfunction occurs, the system reverts to the basic pneumatic braking system. Current government regulations require that initial versions of EBS be equipped with a complete dual-circuit pneumatic system as a backup.

Manufacturers expect to see benefits in maintenance as well. EBS can eliminate the numerous air hoses that travel from the pedal to the relay valves, which means less plumbing and fewer potential leak points.

With its improved diagnostics, EBS can measure key performance characteristics such as brake stroke, brake-lining wear and temperature, helping managers schedule routine brake jobs more efficiently.
Future braking systems will do the following:

• Detect needed replacements and corrections before the component is worn out or the system passes a safe operating limit;
• Alert the driver when a component or subassembly fails;
• Eliminate proprietary operations and maintenance systems;
• Coordinate maintenance needs with normal service intervals;
• Maintain proper adjustment automatically for the design life of the foundation brakes;
• Simplify selection of replacement components;
• Allow for more accurate inspections; Provide driver feedback by means other than warning lights (e.g. longer and harder pedal application); and
• Offer compatibility between tractor and trailer designs.

Tires
After fuel, tires represent a fleet’s second-highest vehicle operating expense, totaling roughly 11 percent of operating costs. Radial tires are the almost-universal choice among today’s fleet operators. Compared with bias-ply tires, radials offer longer mileage, improved casing life, reduced downtime, better traction and handling, improved ride quality and lower rolling resistance for better fuel economy. Tires need to be spec’d for optimum performance on the specific axles (steer, drive and trailer) and for application (over-the-road, city or urban, or off-road).

Although there is no secret to building an effective tire-management program, the trick is execution. Whether conducted in-house or outsourced, an effective tire program directly affects a fleet’s profitability, driver performance, equipment safety and customer service. Developing a tire-management program begins with an accurate account of tire costs. A separate budget will help track acquisition costs, original tread life, fuel efficiency, emergency road service, mounting expenses, casing life, maintenance, labor, equipment and training. The challenge is determining what components are important to the fleet and then concentrating on them.

Without such information, it is tough to manage your existing program, let alone evaluate bids or monitor the effectiveness of an outside tire-management service. If you do not have the right reporting system in place, outside vendors can help you establish one.Ensuring that you have the right tire in the right wheel position to suit your application and road conditions begins with a thorough analysis of scrap tires. If service providers understand how and why your tires failed in the past, they can better recommend what tires run best for which applications and in which positions.


Most experts believe that a solid tire-management program is based on consistency in buying new tires, retreads and supplies. Consistency allows for meaningful comparisons. At the same time, experts advise that standardization not come at the expense of new product evaluations.
By carefully monitoring tire performance, a trucking company can learn which tire is best for its operation, based on wheelbase, equipment configuration and operating conditions.

Once tires are mounted, the maintenance program begins. Most programs are geared toward maintaining proper air pressure, which means performing the time-consuming practice of checking air pressures, even on the inside duals. Many drivers still just thump tires — a practice that is not as effective as using calibrated air-pressure gauges.

Make sure that your drivers check valve caps and visually inspect tires for cuts, holes and irregular wear. Remove bad tires as quickly as possible and replace them with matching tires.

Even the best tire — management program depends on drivers. The person behind the wheel is the biggest variable. How a driver handles a truck determines the amount of scrubbing, flat-spotting and curbing on tires, which can quickly sabotage any effort in the shop.

Alternative fuels
Concerns about rising pollution, especially in congested urban areas, and energy security have prompted the federal government to try to wean the industry off its reliance on fossil fuels. Two complex and overlapping pieces of legislation, the Clean Air Act Amendments of 1990 and the Energy Policy Act of 1992, set the stage for doing just that — mandating a shift to alternative fuels such as alcohols, electricity, natural gas and propane. According to the EPA, gasoline and diesel fuel power 99 percent of the country’s fleet population. That places motor carriers — particularly those that operate in and around the nation’s most polluted cities — squarely in the sights of federal policymakers. Strictly defined, alternative fuels are fuels that can be derived from non-crude-oil resources. That definition applies to all vehicular fuels other than gasoline and diesel, although reformulated gasoline and clean diesel fuels sometimes are considered alternative fuels.

Most of these fuels are used in mass-transit applications of federal fleets. Use in heavy-duty applications is sporadic, primarily due to the lack of clean-fuel engines and chassis — the stated reason for the EPA’s one-year delay in implementing the clean-air rules. Beginning with the 1999 model year, 30 percent of light-duty trucks (up to 8,500 pounds gross vehicle weight rating) and 50 percent of medium-duty trucks (8,501 to 26,000 pounds GVWR) had to be low-emission vehicles. To comply, fleets face several choices, including fuel, vehicle range, refueling options, cost of conversion or acquisition, and performance. Several fuels meet the definition of alternative fuels:

Electric. Battery-powered vehicles emit virtually no pollution and offer one of the best options for reducing vehicle emissions in polluted cities. Power is generated from stationary sources (or onboard fuel cells) through a variety of commonly used feedstocks (coal, oil, gas, nuclear and hydro) and stored in batteries. Although greater advances have occurred in generating stationary power, technology on the vehicle side is advancing rapidly. Within the past year, researchers reported a tenfold increase in power production per unit of weight and unit of volume, opening the door more widely to transportation options.

Despite such progress, the performance of today’s electric vehicles is limited by the amount of power the battery can provide. Concerns remain about durability, manufacturing, materials and infrastructure. Also, the cost remains prohibitively high. Another down side is recharging time. Current batteries take hours to recharge.

Biodiesel. Although biodiesel can be manufactured from a variety of vegetable oils, the type most commonly used in Europe is rape methyl ester (RME), manufactured from rapeseed oil. Methanol is added to the oil, which is produced by crushing rapeseed, and heated in the presence of a catalyst to produce RME and the byproduct glycerin.

Ethanol. A liquid produced from agricultural products, ethanol (or ethyl alcohol) is blended in small amounts (10 percent) with gasoline to produce gasohol. As an alternative fuel, ethanol is blended with 15 percent gasoline to produce a fuel called E85, which can be used in flexible-fuel vehicles that also operate on straight gasoline. Heavy-duty ethanol vehicles use almost pure methanol fuel, or M85. From a performance perspective, power and acceleration are comparable to gasoline. Because it is a cleaner-burning fuel, M85 forms fewer carbon deposits in the engine, reducing wear and maintenance. Its 102 octane rating also helps prevent engine-knock damage. Its range is 70 percent that of gasoline.

Although ethanol requires a relatively inexpensive conversion, it costs more than gasoline and requires the use of special, more expensive lubricants. Public fuel stations are limited, and the price of building your own runs $35,000 to $105,000.
Pure-ethanol fuel offers low hydrocarbon and toxic emissions. It can be produced domestically from corn or other crops, as well as from cellulose materials such as wood or paper wastes, potentially minimizing the accumulation of greenhouse gases.

Methanol. Like ethanol, methanol (or wood alcohol) is a high-performance liquid fuel that emits low levels of toxic and ozone-forming compounds. It is blended with a small amount of gasoline (15 percent) to produce M85. The gasoline blend helps boost cold-weather starting performance. M85 can be used in flexible-fuel vehicles that also operate on straight gasoline. Heavy-duty methanol vehicles use pure methanol fuel, or M100. Methanol can be produced from natural gas at prices comparable to those of gasoline, as well as from coal and wood. All major auto manufacturers have produced cars that run on M85, and some have even developed advanced M100 prototypes.

Although methanol involves lower equipment-conversion costs, the fuel costs more than gasoline. Also, like ethanol, it requires the use of special, more expensive lubricants. Although it offers a range just 60 percent that of gasoline, its power and acceleration are comparable to gasoline. As a cleaner-burning fuel, M85 forms fewer carbon deposits in the engine, reducing wear and maintenance, and its 102 octane rating helps prevent engine-knock damage. One drawback is limited public fueling facilities. The cost of private installation runs $35,000 to $105,000. Another drawback is that it burns with a nearly invisible flame, creating a hidden fire hazard.

Natural gas. Abundant and less expensive than gasoline, natural gas must be stored under pressure in heavy tanks. There are significant tradeoffs for compressed natural gas (CNG) vehicles: emissions, vehicle power, efficiency and range. Natural gas is already used in some fleet vehicles, however, and appears to have a bright future as a vehicle fuel because it emits few toxins and ozone-forming hydrocarbons. Natural gas is primarily methane, along with small amounts of other hydrocarbon gases. For use in vehicles, the gas is compressed or liquefied (LNG) at very low temperatures. There is a 10 percent power loss with natural gas, but that loss is partially offset by the use of higher compression ratios to boost efficiency and power. Because it burns cleaner than diesel, natural gas reduces carbon deposits inside the engine. Oil-change intervals and engine life can be extended.

Because the gaseous fuel need not be vaporized before entering the engine, natural gas improves cold-weather starting. One downside is that it offers a range only 30 percent that of gasoline when compressed and about twice that when stored as a liquid.
A small but growing public distribution infrastructure network provides refueling. Quick filling is possible, but most private fueling facilities are designed for overnight fueling. Private facilities cost $25,000 to $250,000.

Propane. Liquefied petroleum gas (LPG, propane being the most common) is stored and transported as a liquid under moderate pressure (125 to 200 psi). Vehicles currently account for less than 4 percent of demand for propane, which is perhaps the most economical alternative fuel. Many light-duty fleets that use it report lower operating and maintenance costs. Conversion from gasoline to propane averages about $2,000.

Propane offers performance similar to that of gasoline in terms of power and acceleration. Its higher octane number helps prevent engine-knock damage and allows the use of higher compression ratios to boost efficiency and power. Because propane burns cleaner, it reduces carbon deposits inside the engine. In addition, it boosts cold-weather performance because it enters the engine in a vaporized state.

A relatively dense fuel, propane offers higher fuel-storage capability compared with compressed natural gas, making it easy to transport. It is comparable to gasoline in terms of refueling time and procedure, by means of a special nozzle that fills vehicles at a rate of 10 to 12 gallons per minute. It also boasts the longest range of any clean fuel, except LNG, for an equivalent volume. It is readily available through a network of refueling stations throughout the country.

Another benefit of propane is that it offers 80 percent of the range of gasoline, allowing vehicles to get by with smaller tanks than those required for other alternative fuels. It must be stored in a sealed, pressure-tight system at all times, however.
Switching an engine to propane requires a converter that serves as a vaporizer and pressure regulator; an air-gas mixer, which mixes the propane with air; a control processor, a computer that adjusts fuel delivery; and an automatic safety lockoff valve that shuts off fuel flow when the engine is not running. Conversion costs run about $2,500.

Reformulated gas. The petroleum industry is beginning to market gasoline formulations that emit fewer hydrocarbons, nitrogen oxides, carbon monoxide and toxins than conventional gasoline. These new gasolines can be introduced without major modification of existing vehicles or the fuel distribution system. The Clean Air Act required some gasoline modifications to reduce carbon monoxide emissions beginning in 1992 and the use of reformulated gasoline in certain polluted cities beginning in 1995.

Clean diesel. Clean (or city) diesel is a special grade of high-quality fuel that has better environmental characteristics than the standard grade. Such fuels have very low levels of sulfur (typically, 0.001 to 0.005 percent by weight), low density, low aromatics, a narrow boiling range and a high cetane number to minimize emissions.

Lubrication
The continuing demand for lower emissions has required continuing improvements in engine oils. Because cooled EGR technology reduces peak cylinder temperatures, it increases condensation of water and acids in the engine and may increase oil sooting. New oils, therefore, must be capable of dispersing the increased soot. The latest crankcase oil standard from the American Petroleum Institute is CI-4, which went into effect in 2002 — shortly before the changeover to the new engines. Some oil suppliers were able to meet the CI-4 standard with the same products that had been certified to CH-4 standards.

Petroleum-based and semisynthetic transmission and gear oils have improved tremendously in recent years and have allowed greatly extended drain intervals and improved warranties once feasible only with more expensive fully synthetic lubricants.

Lighting
When it comes to lighting systems, the advantages of light-emitting diodes are many: longer life, reduced maintenance, less power drain and increased safety margins. But these benefits originally came at a price 10 times that of incandescents. But with new technology driving down cost and recent mandates for antilock braking systems on trailers, trucking companies are looking anew at LED technology.

The power requirement for ABS is significantly greater than that of older braking systems. By running a full trailer or trailers with incandescent lights, you risk compromising ABS power.

The industry has agreed that at least 9.5 amps are needed to power ABS, making LEDs an attractive lighting-system option. They offer 1/8 the amp draw of their incandescent cousins, and their price has dropped to about three to five times the price of incandescents. Besides becoming more price-competitive, LEDs are getting better. New diodes disperse four times the output of first-generation models. Couple that with improvements in optics and lenses, and today’s versions allow manufacturers to use fewer diodes than current designs and still comply with federal regulations.

LEDs also are more reliable. Incandescent lamps contain a tungsten filament wire. When current flows through the filament, it encounters resistance and the wire heats up and glows brightly. Over time, the tungsten evaporates and the wire burns out. This occurs between 200 and 15,000 hours, depending on the incandescent bulb and the presence of shock and vibration.

By contrast, the LED is a solid-state-electron component. When current flows through the semiconductor compunds, light is emitted. Because there is no evaporation of components and because the diode is in a solid state — not affected by shock and vibration — the life span of an individual LED is up to 100,000 hours.

In Summary
Today’s trucking companies demand more from their vehicles: improved performance, lower maintenace costs,
extended lubrication intervals, longer life, greater fuel economy and reduced life-cycle cost.
Manufacturers are answering these demands with increasingly sophisticated components and systems. Staying abreast of changes to engines, suspensions, transmissions, fuels and lubricants is critical to running a safe and efficient fleet.