White Paper on Powertrain Spec ing

Transcription

1 KENWORTH. The World s Best. White Paper on Powertrain Spec ing January 2005

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3 WHITE PAPER OVERVIEW This Kenworth White Paper on Powertrain Spec ing was developed to provide useful information and recommendations on the new generation of heavy duty engines, transmissions, cooling systems, and related technology to ensure maximum performance, fuel economy and minimum vehicle life cycle costs. There are seven major areas covered in this Kenworth White Paper: Cummins Engines page 1 Caterpillar Engines page 3 Engine Cooling Systems page 6 Spec ing Considerations for Powertrain Lubricants page 7 Automated and Automatic Transmissions page 8 Axles and Drivelines page 10 Suspensions and Traction Control Options page 13 CUMMINS ENGINES Technology Overview Cummins emission technology uses cooled Exhaust Gas Recirculation, or EGR. This process takes a small amount of exhaust gas from the exhaust manifold, sends it through a cooler to reduce the temperature, and then blends it with fresh intake air before it goes into the combustion chamber. This added exhaust gas helps lower the combustion temperatures and reduces emissions while maintaining power and efficiency. A key feature of Cummins new engines is the Holset Variable Geometry (VG) turbo. This design constantly adjusts airflow based on engine load, fuel quantity, ambient pressure, temperature and other conditions to provide the exact amount of boost needed at any engine speed. This unique design uses a single sliding nozzle with only one moving part in the exhaust stream. The Holset VG turbo is proven technology and is more reliable and durable by design than other competitive designs due to fewer moving parts. Most truck owners will see no change from their current preventive maintenance intervals, including engine oil and filter changes. The Cummins ISX is designed to operate between service intervals in normal service use up to 25,000 miles. The Cummins ISX is designed to operate up to 25,000 miles between service intervals in normal service use. PowerSpec Tool Cummins PowerSpec is an application available from the Internet that allows users to establish feature and parameter settings, gearing recommendations and basic trip and fault information. By selecting an engine application and answering a few simple questions, PowerSpec will provide gearing recommendations specific to the intended service. Users can enter specific component options to determine what combination of tires, transmission and rear axle Visit to download PowerSpec and learn more about spec ing Cummins engines. will optimize the vehicle performance. Kenworth dealers can work with customers using PowerSpec to create and load feature settings prior to delivery of the vehicle to the customer. 1

4 Key PowerSpec features and parameters include: Road Speed Governor Setting determines how fast the vehicle travels on level ground to ensure optimum fuel economy. As a rule of thumb, fuel economy decreases by 1/10 mpg for every mile per hour above 55 mph, primarily as a result of higher aerodynamic drag. Idle Control sets the engine shutdown time and adjusts idle speed control to improve fuel economy during inactive operation. Heavy duty engines typically use 0.5 gal/hr at 650 rpm and 1.0 gal/hr at 1,000 rpm. Gear Down Protection promotes increased fuel economy by encouraging the vehicle driver to operate as much as effectively possible in top gear where fuel consumption is lower. This is accomplished by limiting vehicle speed in lower gears. Maximizing time in top gear means the engine runs in a lower rpm range, thus producing increased fuel economy and improved durability. 2 Engine Brake Settings allow the operator to customize the brake application and operation to best suit the driving conditions. These options include the rate of brake application and the vehicle speed range in which engine braking is allowed. Additional Cummins Features to Achieve Maximum Performance and Fuel Economy It is crucial to ensure that vehicles are spec d properly to balance fuel economy and performance needs. PowerSpec, in conjunction HOW IMPORTANT IS SPEC ING TRANSMISSION AND REAR-AXLE GEARING ON FUEL ECONOMY? Based on Cummins testing, an engine geared to run 1,450 rpm at 65 mph gets approximately 4 percent better mpg than one geared to run 1,600 rpm at 65 mph. with the driver s experience, will help optimize the vehicle gearing to achieve these objectives. Cummins SmartTorque (ST) rated engines help drivers to drive smarter by providing up to 200 lbft of extra torque in the top two gears. Using ST promotes top gear usage resulting in a higher percentage of time in top gear that translates into improved fuel economy. This is accomplished by allowing added peak torque under conditions where it s needed when in either of the top two

5 gears. SmartTorque minimizes shifts, which enhances fuel economy and driver satisfaction. Load-Based Speed Control (LBSC) is Cummins engine management system that helps save on fuel while providing power when needed. LBSC works intelligently to understand the vehicle s operating conditions to balance performance and fuel economy based on the Gross Vehicle Weight (GVW) and grade. When maximum performance is not required, LBSC manages the operating range of the engine for maximum fuel efficiency. LBSC also automatically ensures that the full operating capability of the engine is available when additional performance and operating flexibility is needed, including: CATERPILLAR ENGINES Cat Heavy-Duty ACERT Overview Caterpillar has developed ACERT to provide optimal combustion efficiency and produce minimal emissions. The technology utilizes two When driving in the top two gears When climbing grades When making gear changes RoadRelay 4 RoadRelay 4 gives drivers the means to increase productivity by reducing idle time and improving fuel economy, delivery performance and more. The display provides information while they are driving to help improve driving habits and fuel economy. Key features include: Trip and Route: Information is displayed and recorded, including fuel, miles and engine hours spent in idle, PTO and other operating modes. Vehicle Protection: RoadRelay 4 constantly monitors the powertrain. If an unexpected event happens, RoadRelay 4 will inform the driver and advise how to minimize potential damage. It also tracks customizable service intervals for oil changes, filter changes and tire rotations, notifying the driver when it s time to head for the shop. Anti-theft: RoadRelay 4 comes with anti-theft capability. This feature protects the vehicle from theft when enabled. turbochargers in series, fuel systems, variable valve actuation, and exhaust after-treatment. Electronic controls manage the system. ACERT uses a cross-flow cylinder head with four valves per cylinder. To achieve high performance and low emissions, the objective of ACERT is twofold: get more clean air into the engine and provide more uniform dispersion of that air charge. ACERT uses proven turbochargers with mechanical waste gates for increased performance. Series turbochargers (two standard turbos in series) provide the low-end response of a small turbo with the higher-speed air volume and boost pressures of a large turbo. Improved fuel economy is an added benefit of this approach. Maintaining optimized conditions requires that the right amount of fuel be delivered at the right time under the right pressure. Caterpillar engineers have found that by providing multiple injections, they can better control emissions. Managing these brief events requires the world s best injector technology from Caterpillar the Mechanically Actuated and Electronically Controlled Unit Injection system. This multiple-injection system is proven technology based on millions of hours of successful realworld experience. 3

6 4 Caterpillar has developed ACERT to provide optimal combustion efficiency and produce minimal emissions. The technology utilizes two turbochargers in series, fuel systems, variable valve actuation, and exhaust after-treatment. Electronic controls manage the system. Variable valve actuation, controlled by electronics, provides precise delivery of cooled air for efficient, clean combustion. This technology provides air delivery to meet varying engine demands based on a wide range of factors, such as coolant temperature, engine speed, throttle position and more. Controlled by Cat advanced electronics, this system allows just the right amount of air for efficient and clean combustion. This system also uses components from proven SPEC ING TIPS FROM KENWORTH FOR CATERPILLAR ACERT ENGINES A transmission with close steps in the top gears can provide a closer match to recommended engine speed. Double-overdrive transmissions should be considered. A transmission that provides automatic shifting in the top two gears will assist the driver in maintaining the proper engine speed over moderate-grade road terrain. To achieve optimum fuel economy, use direct or overdrive transmissions with Gear Down Protection to ensure that cruising speed can only be reached in top gear. Spec multi-torque engines for applications requiring less than 1,650 lb-ft torque. These ratings provide additional torque in the top four gears. With the additional torque, the truck will have greater ability to crest a hill without downshifting to improve fuel economy, reduce engine wear and increase driver satisfaction. Caterpillar technology. Benefits of variable valve actuation include low emissions and improved fuel economy. Diesel oxidation catalyst after-treatment converts hydrocarbons into carbon dioxide and water. The process is fast, efficient and reliable. Achieving Maximum Performance and Fuel Economy Caterpillar Caterpillar has developed new guidelines for gaining maximum fuel efficiency and performance from ACERT engines, which may differ from previous Caterpillar engines. As with all engines, engine fuel consumption changes when operated at different engine speeds. Caterpillar s recommendation to gear fast, run slow still applies on all Cat Heavy Duty engines. For most applications, there are some differences in Caterpillar ACERT drivetrain specs that should be followed to achieve the best balance between fuel economy and performance in a Kenworth truck. In most cases, ACERT engines will be spec d at lower engine rpm than prior generations of Caterpillar heavy duty engines. For most applications, there are some differences in Caterpillar ACERT drivetrain specs that should be followed to achieve the best balance between fuel economy and performance in a Kenworth truck. ACERT ELECTRONIC PARAMETERS Programmable electronic parameters are available to ensure proper engine operation. Setting parameters correctly will maximize fuel economy and control engine life cycle costs. Parameters such as Vehicle Speed Limit, Low and Intermediate Gear Limits, High Cruise Control Speed Limit, Gear

7 Spec ing Guides for Caterpillar ACERT Engines. Caterpillar ACERT Gearing Recommendation. Gross Combination Line-Haul Cruising Speed Engine Weight (lb) for Maximum Fuel Economy Comments C7 < 50, mph 2,000 rpm VSL should be set to prevent excessive speed. > 50, mph 2,200 rpm C11 < 60, mph 1,450 rpm Vocational Cruise Speed: Rear-axle ratio may need to C13 Non Multi-Torque and < 80, mph be spec d at higher engine rpm to meet gradeability and startability guidelines. C13 Multi-Torque 1,450 rpm Vocational Cruise Speed: Driveline may need to be 410 hp 1,450/1,650 lb-ft C13 < 80, mph spec'd at higher engine rpm to meet gradeability and startability guidelines. Multi-Torque 1,325 rpm Vocational Cruise Speed: Driveline may need to be 430 hp 1,550/1,750 lb-ft C15 80,000 Less than 1,750 lb-ft spec'd at higher engine rpm to meet gradeability and startability guidelines. Non Multi-Torque 65 mph 1,400 rpm 1,750 lb-ft and above 65 mph 1,325 rpm Heavy Hauler Cruise Speed: 1,500 1,650 rpm Vocational Cruise Speed: Driveline may need to be C15 80, mph spec'd at higher engine rpm to meet gradeability and Multi-Torque 435 hp 1,325 rpm startability guidelines. 1,550/1,750 lb-ft and 475 hp 1,650/1,850 lb-ft Vocational Cruise Speed: Driveline may need to be spec'd at higher engine rpm to meet gradeability and startability guidelines. 5 Down Protection and Idle Control can be set during the vehicle order or pre delivery process. Startability Startability is the ability of the vehicle to pull away from a dead stop on a grade. Depending on vocation, Caterpillar recommends following these startability performance guidelines: 10% Pickup and Delivery 14% Line-Haul 20% On-Off Highway Gradeability At peak torque rpm in top gear, Caterpillar recommends a minimum gradeability performance threshold of 1.8%. At cruise speed in top gear, 1.0% gradeability is ideal to achieve best performance. Gearing Recommendations for Caterpillar ACERT Engines The chart above provides some general guidelines to consider when spec ing Caterpillar ACERT engines. 25% Off-Highway

8 6 The following example compares a typical Owner Operator gearing comparison (80,000 lb GCWR and less) with the new Caterpillar ACERT engines. Pre-ACERT Cat Spec Typical Spec Type Recommendation New Cat ACERT Spec Engine Rating 550 hp 1,850 lb-ft 550 hp 1,850 lb-ft Transmission RTLO 18913A RTLO 18913A Rear-Axle Ratio Tires 285/75R /75R24.5 Cruising Speed 1,410 rpm at 65 mph 1,300 rpm at 65 mph Gradeability at Cruise Startability 1st Gear Startability 2nd Gear Caterpillar Messenger In 2003, Caterpillar introduced a new driver message display for monitoring engine performance and operating information. CAT Messenger graphically displays and records fuel usage and average miles per gallon to monitor individual performance in achieving fuel economy goals. Messenger can also be enabled to alert drivers to preventive maintenance inspections and oil changes. Messenger displays the codes, indicating a potentially serious engine problem automatically by displaying diagnostic codes, with both a number and a brief text explanation. Security features of Messenger provide the capability to allow or prevent engine starting, or to shut the engine down by entering a 4-character password into the display when the engine is at idle. Other information that can be stored and displayed includes: Vehicle trip information, including average vehicle speed Cruise control set speed Fuel economy and fuel used Power Take Off (PTO) engine rpm set speed, operation time and fuel consumed Percent idle time, fuel consumed Fuel temperature to the engine Boost and oil pressure Coolant temperature Intake manifold temperature ENGINE COOLING SYSTEMS All Kenworth radiators and charge-air-coolers are designed to optimize the performance of the vehicle horsepower and torque requirements to the vocation, especially when running at full throttle at low speeds for extended periods of time in high ambient conditions. Kenworth uses five basic sizes of cooling modules: Cooling Module Size (square inches) Models 840 T W900S 1,200 T800, W900L, T2000 and T600 1,430 W900B, T800H 1,520 T800W Kenworth now offers a High Performance Engine Cooling Ring Shroud to provide additional cooling capacity with high horsepower and/or gross combination weight ratings at or above 80,000 pounds. The High Performance Engine Cooling Ring Shroud is mounted to the engine and reduces fan blade tip clearance to promote more efficient airflow over the cooling module. Extended Life Coolant Extended life coolants (ELC) are a popular option which allow operators to run the latest generation of heavy duty diesels to overhaul, with no supplemental coolant additives or coolant changes necessary. Extended-life coolants offer cooling system protection for up to 300,000 miles. ELC contains no silicates, nitrates, borates, phosphates, amines, or other abrasive dissolved solids that can

9 All Kenworth radiators and charge-air-coolers are designed to optimize the performance of the vehicle horsepower and torque requirements to the vocation, especially when running at full throttle at low speeds for extended periods of time in high ambient conditions. contribute to water pump seal wear. It provides long-term corrosion protection for all cooling system metals, including copper, brass, steel, lead solder, cast iron and aluminum. It also offers exceptional protection against pitting for wet sleeve cast iron cylinder liners in heavy duty engines and eliminates the need for the addition of traditional supplemental coolant additives (SCAs). Unlike traditional coolants that require SCAs at 12,000- to 20,000-mile intervals, long-life coolant requires only one recharging with an extender product at 150,000 miles. 7 SPEC ING CONSIDERATIONS FOR POWERTRAIN LUBRICANTS Engine Oil Specifications for Low Emission Engines Kenworth Truck Company and its supplier, ChevronTexaco, have taken steps to ensure that the new generation of engine oils is compatible with engine manufacturer requirements for the new engine emissions standards. In June 2003, Kenworth manufacturing plants transitioned to a new formulation of Delo 400 multigrade oil. This new formulation was optimized to meet the demands of Cummins EGR engines while at the

10 8 Kenworth Truck Company and its supplier, ChevronTexaco, have taken steps to ensure that the new generation of engine oils is compatible with engine manufacturer requirements for the new engine emissions standards. same time providing the highest level of performance with Caterpillar ACERT engines. Delo 400 multigrade provides excellent soot control, acid neutralization capability, maximum thermal stability, and wear control while minimizing diesel engine piston deposits. Synthetic Transmission and Axle Lubricants Kenworth trucks come standard with factoryfilled synthetic lubricants. The products, which include SAE 50 synthetic manual transmission fluid, 75W-90 synthetic axle lubricants and the optional 80W-140 synthetic axle lubricant, meet the Dana/Eaton Roadranger extended 750,000- mile warranty and 500,000-mile extended lubricant drain interval requirements. Synthetic lubricants provide superior all-climate performance. The high viscosity index, low pour THE NEW FORMULATION FOR KENWORTH S FACTORY FILL DELO 400 MULTI-GRADE MOTOR OIL IS COMPATIBLE WITH OLDER ENGINES Delo 400 multigrade heavy-duty motor oil provides outstanding protection under both pre- and post-2002 EPA standards. This product can also be used in EGR-equipped engines from other diesel engine manufacturers as well as in all pre heavy-duty diesel engines. Packaged product labels have been updated to reflect the new Caterpillar ECF-1 claim and will appear in circulation as older inventories are depleted. point and subzero fluid flow provide for easier cold-weather shifting, less drag and less gear wear because vital transmission parts are lubricated quickly. Since it is highly stable when exposed to severe heat, oxidation and shear conditions, synthetic lubricants provide exceptional hightemperature lubrication for extended drain intervals. Synthetic transmission and axle lubes also provide several low costs of operation benefits. They provide antiwear additive, as well as rust, oxidation and corrosion inhibitors that protect bearings and synchronizers, reduce component wear and promote longer transmission and lubricant life. KENWORTH TRUCKS COME STANDARD WITH SYNTHETIC TRANSMISSION LUBRICANTS TO PROVIDE PREMIUM VALUE Superior Lubrication for Less Friction and Drag Better Fuel Economy Reduced Vehicle Downtime Lower Maintenance Costs AUTOMATED AND AUTOMATIC TRANSMISSIONS Automated and automatic transmissions are a growing trend in the industry. There are two primary types: Automatic Transmissions Automated Manual Transmissions Automatic Transmissions from Allison Automatic transmissions use a torque converter in lieu of a clutch. The torque converter can provide strong starting power, especially on hills or in soft terrain. The torque converter multiplies the engine s torque, so the first gear offers similar ratio coverage as the first two or three gears of a manual transmission. Another feature of automatic transmission is no power interruption between or during shifts, which can provide better acceleration, smoother ride and reduced shock loading of the drivetrain, compared to a

11 Automated and automatic transmissions are being recognized for higher productivity and driver satisfaction. manual transmission. Electronic controls continuously monitor engine rpm, load and terrain to keep the vehicle operating at peak performance and optimum fuel economy. Automated Manual Transmissions from Eaton Corporation With an automated manual, electronic controls and electromechanical actuators take the place of the manual shift lever. Some versions, such as the all new Eaton Fuller UltraShift, require no SMART TRANSMISSION SPEC ING TIP FOR FLEETS The Eaton Convertible Transmission is an innovative life cycle cost solution targeted at fleet customers. The base transmission is a 13-speed, which is operated as a 9-speed for the truck s first life operation. At resale, the Convertible Transmission can be easily upgraded to a 13-speed for higher resale. An excellent feature of the Eaton Convertible Transmission is that it is available with a Top2 feature. As with other Top2 models, the top two gears shift automatically. In a convertible transmission, this means that the Top2 gears are from a 13-speed transmission, providing a 17 percent gear step. This step size is ideal for the narrow fuel economy rpm window of some new technology engines. As an added incentive, the Eaton Convertible transmission comes standard with a 5-year / 500,000-mile warranty. When converted to a 13-speed, there is an additional oneyear / 100,000-mile warranty included with the conversion kit upgrade. 9 clutch pedal for starting or stopping the vehicle. Shifting is fully automatic once the vehicle is in motion and managed by an onboard computer which can provide fast and smooth shifts. The transmission electronic control unit calculates the vehicle load and, depending on the throttle position and other inputs, provides the best gear selection for the situation. Eaton s Top2 feature with the Lightning transmission is another form of an automated

12 10 manual transmission designed specifically for pickup and delivery and over-the-road applications. The Lightning Top2 feature can eliminate up to 80% of the shifts on highway and urban roads. When shifting between 9th and 10th gears, this solenoid, which is electronically controlled by the transmission ECU, initiates the shifting. As the terrain or vehicle speed varies, the Top2 shift logic in the electronic control unit determines which of the top two gears is best and automatically makes the shift at the right time for optimum economy and performance. Features, Advantages and Benefits of Automated Manual and Automatic Transmissions Automated and automatic transmissions are being recognized for higher productivity and driver satisfaction. With automated shifting, the driver can more easily utilize both hands on the steering wheel and focus their concentration on traffic and the road. Other benefits of automated and automatic transmissions include: Automatic or automated shifting controls driveline shock in components such as the clutch, yokes, driveshaft and drive axle components. Electronic fault management features alert the driver of problems and carry out an automatic fault analysis. Resale values for trucks spec d with automated or automatic transmissions can command a premium ranging from $2,500 $5,000 compared to a manual 10-speed, depending on the vehicle condition and age. AXLES AND DRIVELINES When spec ing a truck, careful attention must be paid to the drive axle, driveline and rear suspension in order to optimize the truck s performance and, ultimately, its profitability. The drive axle is one of the most critical components in a truck. Ensuring that the axle is appropriately specified could mean the difference between a good performing truck and a breakdown. Before choosing the rear axle, information about the truck specification and application must be known to identify the right axle for the job. As the duty cycle is uniquely different for each intended service, the application guidelines for any one axle will vary as well. Axle Spec ing Considerations Assessing the intended service of the truck is critical for axle selection. Duty cycles of the vehicle must be considered, including annual mileage, distance between starts and stops, percent of load going versus returning, road surface type and grades. As the duty cycle is uniquely different for each intended service, the application guidelines for any one axle will vary as well. In addition, the details of the truck specification must be known, such as gross axle weight rating, gross combination weight, gross vehicle weight, engine horsepower and torque, and the desired rear-axle ratio. In a number of cases, the transmission low-gear ratio and tire size are also required to accurately determine the appropriate axle.

13 An axle that may be suitable with a 600- horsepower engine in a line-haul application may not be approved for a pickup and delivery (P&D) application with even less horsepower because the duty cycle is more demanding due to the frequent starting and stopping associated with P&D. For example, let s take a look at the Dana Spicer Application guidelines for the DSH40 tandem axle. In a line-haul application, the axle is approved for 600 horsepower and 2,050 lb-ft of torque with a GCW of 125,000 lbs. But in the P&D application, the maximum allowable is 550 horsepower and 1,850 lb-ft of torque and a GCW of only 90,000 lbs. This is just one example of how a truck s intended service and application can impact the approval, reliability and performance of the drive axle. It is important to take the appropriate steps up front in the truck spec ing process to accurately identify the intended service, application duty cycle and drivetrain details. Doing so can help reduce the potential for axle failure while also working to optimize the performance of the drive axle in terms of reliability, durability and weight capacity. Your Kenworth dealer not only has access to a powerful sales tool but can also work with the Kenworth Application Engineering Department to help spec the right axle to pull and support the load, fine tune the driveline combination to optimize performance and efficiency, answer questions and offer spec ing tips for your unique truck application. Double-Reduction Axles Conventional tandem axles achieve torque multiplication by transferring torque through one ring and pinion set. A double-reduction axle transfers torque through a planetary or helical gear set in the input carrier first and then through the ring and pinion. By dividing the torque multiplication between two gear sets instead of just one, internal stresses on gears and bearings are reduced. The result is an axle with high resistance to shock loading and improved vehicle startability, making it an ideal choice for heavy-duty and off-highway applications. Planetary Wheel End Reduction Axles Typically used in mining, logging, oil field and heavy-haul applications, planetary axles are the choice for extreme heavy-duty and off-highway applications requiring high gross weights. Similar to a double-reduction axle, the planetary axle achieves its torque multiplication with two gear sets. However, instead of a gear set in the input carrier, the planetary axle first transfers torque through the ring and pinion and then through a final planetary gear set in the wheel end. The result is an axle with high tolerance for heavy loads. Kenworth offers planetary axles with GAWR s ranging from 58,000 lbs up to 150,000 lbs and GCW s up to 1 million lbs. Traditionally, planetary axles have been speed limited to mph in order to avoid excessive heat buildup in the planetary gear set, and this is largely true for the axles in the high end of the capacity range. However, Kenworth offers planetary axles with GAWR s ranging from 58,000 lbs to 70,000 lbs and GCW s up to 330,000 lbs that can operate at highway speeds without exposure to overheating of the planetary gear set. These axles make an ideal choice for heavy-haul and prime-mover applications that haul loaded at slow speed one way and return home empty at highway speed. Dual Range (Two-Speed) Axles There are applications that require a truck to not only operate at normal highway speeds, but also at very slow, steady speeds when pulling heavy loads out of muddy job sites or maneuvering on uneven terrain. A transmission with a wide ratio coverage, such as an 18-speed, will often meet the needs of most heavy-haul applications. But for those who need extra reduction, a dual range axle is an alternative to an auxiliary transmission that deserves consideration. Dual range axles are based upon the same technology used in double reduction axles discussed previously. Like the double reduction axle, the dual range axle utilizes a planetary gear set in the input carrier to compound the ratio of the ring and pinion. Unlike the double reduction axle, the dual range axles give the operator the capability to engage via a dash-mounted switch the planetary gear set for low-range slow-speed pulling, or disengage the gear set for high-range highway operation. Tridem Drive Axles While not particularly suited for over-the-road use, tridems offer a number of advantages for truck applications that demand time and mileage off the pavement, such as logging, oil field service 11

14 12 and mining, to name a few. With three axles instead of two, tridems allow more load to be carried on the drive axles, providing more tractive effort. Additionally, the tridem axle provides greater floatation and improved mobility in loose surfaces. This is achieved by distributing the driveaxle load over a greater surface area than a tandem axle. Tridem axles are available on Kenworth trucks in capacities from 58,000 lbs up to 105,000 lbs. Front Drive Axle 4x4, 6x6, 8x6, 8x8 Configurations If your application demands the ultimate in traction, a front drive axle is likely to be the solution. When a front drive axle is added to a truck, there are a number of drivetrain and chassis components that are affected as a result. First, a transfer case must be added to power the axle. Transfer cases are available in a variety of torque capacities and configurations. Second, a front drive axle requires that the chassis be raised approximately nine inches to provide adequate clearance between the engine oil pan and the axle housing. This usually requires the addition of a rear suspension subframe to level the chassis. A final consideration is insuring that the front and rear axles turn at or very close to the same speed. The speed at which the axles turn can be altered by the axle ratio and tire size. A good rule of thumb when spec ing a front drive axle is to There are applications that require a truck to not only operate at normal highway speeds, but also at very slow, steady speeds when pulling heavy loads out of muddy job sites or maneuvering on uneven terrain.

15 ensure that the speed of the front and rear axles are within 1% of each other. A truck that has improper mismatch will encounter excessive tire wear and potentially premature damage to drivetrain components. Many truck manufacturers outsource installation of front drive axles to aftermarket up-fitters. The Kenworth factory installs front drive axles to the highest of engineering and manufacturing standards and backs them with a Kenworth factory warranty. Drivelines Kenworth trucks are standard with the proven Dana Spicer 10-Series driveline yet are also available with the low-maintenance Dana Spicer Life XL-Series. Featuring a lightweight design and improved sealing technology, the first lube is not required until three years or 350,000 miles for onhighway applications. While it may appear to be simple, the proper installation of a driveline involves a careful balance of drivetrain and chassis component location combined with rigorous calculations to ensure that drivetrain vibrations are minimized. Variables in the chassis specification, such as the engine, transmission, wheelbase, suspension, axle and even tire size, contribute to driveline design. Every Kenworth drivetrain is custom designed to provide optimum performance and not only meet but exceed the requirements of driveline manufacturers. SUSPENSIONS AND TRACTION CONTROL OPTIONS Suspensions For many years, air suspensions have been regarded as strictly on-highway suspensions due to their relatively low level of axle articulation and propensity for getting stuck in off-road conditions, leaving vocational duty to mechanical walking-beam or spring-type suspensions. As demand for smoother riding and better handling trucks has been increasing over the years, so too has the demand for air ride suspensions. Kenworth, one of the pioneering companies in air suspension technology, has continued development of air suspensions since the introduction of its proprietary AirGlide 100 in the 1970s. Today Kenworth offers an extensive lineup of proprietary air suspensions from its ultra lightweight AG380 to its family of 8-bag air suspensions, including the AG400, AG460 tandems and the AG690 tridem suspension. The AG400/460/690 suspension family s 8-bag design yields a smooth, stable ride and features a lightweight yet durable one-piece swaybar that provides up to 6" of axle travel and allows for high axle cross-articulation. Unlike competing air suspension designs, the AG400/460/690 suspension does not use the axle housing as a torsional member, improving the life of the axle. The result is an air suspension that minimizes stress in the frame and cross-members and provides outstanding traction in off-highway conditions. The Kenworth AG400, AG460 and AG690 are excellent choices for a number of on/off-highway applications, including logging and heavy haul. 13 Inter-axle Differential Lock Kenworth provides the inter-axle differential lock as a standard feature and also provides an option that restricts use of this feature while the transmission is in high range. When engaged (locked), the differential is inoperable and the available input torque is distributed to both axles, ensuring the vehicle maintains traction. This feature is typically used at slow operating speed to minimize the potential differential damage to the forward axle.

16 Wheel Differential Cross-Lock For vocational trucks that traverse off-road surfaces, Kenworth offers a wheel differential lock (also known as a cross-lock) that, when engaged, distributes the available torque to all wheels, ensuring the power is delivered to keep the vehicle moving. Central Tire Inflation System Dana Spicer Central Tire Inflation System (CTIS) provides enhanced mobility through improved flotation and traction by the adjustment of tire pressures. In off-road vocational applications, CTIS has grown in popularity as an effective alternative to all-wheel drive, providing good off-road performance with far less weight, cost and a lower overall vehicle height. CTIS features operatorcontrolled inflation and deflation of all the vehicles tires based on terrain, speed and load. Automatic Traction Control Feature Advantage and Benefit Automatic Differential Braking Reduces potential of powering into a jackknife caused by wheel overspin during acceleration or in curves. Provides primary control when drive wheels are operating on different surfaces; when one wheel spins, ATC momentarily applies the brake on that wheel to gain traction. Electronic Engine Control If both wheels on the sensed axle are on a poor-traction surface, ATC automatically reduces engine power to attain optimum tire-to-road traction. ATC Light on Dashboard Indication of slippery road conditions. 14 Automatic Traction Control Automatic Traction Control (ATC) is an optional feature of Kenworth s Antilock Brake System (ABS). When a difference in speeds between wheels occurs during acceleration, the ATC is activated, controlling wheel spin to provide improved traction. Other features of ATC are noted above.

17 Spec ing Guidelines for Air Suspensions Kenworth Air Suspension AG380 AG400 AG460 AG690 Configuration Tandem Tandem Tandem Tridem Ride Height 8.5" 9" 10.5" 10.5" Rated Capacity 38,000 lbs. 40,000 lbs. 46,000 lbs. 69,000 lbs. Axle Spacing 52" 52", 54" 52", 54", 60" 54" Intended Service Line-haul Line-haul Line-haul Line-haul Local P&D Local P&D Local P&D Local P&D EMT/Rescue/Fire EMT/Rescue/Fire EMT/Rescue/Fire Heavy Transport Heavy Transport Heavy Transport Wrecker* Wrecker* Wrecker* Crane/Picker* Crane/Picker* Crane/Picker* Oil Well Servicing Oil Well Servicing Oil Well Servicing Loggers Loggers Loggers Agriculture* Agriculture* Agriculture* Construction* Construction* Construction* Snowplows Snowplows Snowplows Dump Dump* Dump* Body Type Van All except All except All except Beverage Mixer Mixer Mixer Tanker Refuse Refuse Refuse Flatbed Roll Off* Roll Off* Roll Off* Road Usage % A&B % A&B % A&B % A&B 5% C 10% C 10% C 10% C 0% D 0% D 0% D 3% D 15 * Review required by Kenworth Application Engineering. SUMMARY Proper spec ing of the vehicle s powertrain is crucial to achieve high productivity and low life cycle costs. The Kenworth Dealer Network of nearly 300 locations in the U.S. and Canada provides assistance in selecting the optimum powertrain for your application through a state-ofthe-art, Kenworth PROSPECTOR vehicle spec ing system. Kenworth dealers are backed by the World s Best engineering organization, which can provide a wide range of technical and applications assistance.

18 Drivetrain Spec ing - General Recommendations 16 Electronic Minimum Enhancement Engine Minimum Gradeability* Minimum Traction Intended Service Parameters Horsepower (Cat Only) Startability Transmission Drive Axle Suspension Features Line-haul Multi-torque ratings; % 18% at 14% 9-Spd 40K Air Traction Idle shutdown timer; peak torque in top Convertible, Control On/Off fan controller; gear, 1% at cruise 10/13-Spd Gear down protection; in top gear P & D Driver reward; Duty cycle monitor Idle shutdown timer; % 18% at 10% Automatic and 21K - 40K Air or Traction ON/OFF fan controller peak torque in top Automated; Leaf Spring Control gear, 1% at cruise 10-Speed in top gear Manual Dump Gear down protection; % 18% at 16% 20% 10/11/13/18-Spd 40K-46K Walking Wheel Idle shutdown timer; peak torque in top Manual or Allison Thick Wall Beam Diff-locks ON/OFF fan controller; gear, 1% at cruise Automatic Housing PTO parameters in top gear Mixer ON/OFF fan controller; % 18% at 16% 20% 11-Spd 40K-46K Walking Wheel PTO parameters peak torque in top Manual or Allison Thick Wall Beam Diff-locks, gear, 1% at cruise Automatic Housing CTIS, 6x6 in top gear Logger Gear down protection; % 18% at 16% 20% 13/15/18-Spd 40K-46K Air or Wheel Idle shutdown timer; peak torque in top Thick Wall Walking Diff-locks ON/OFF fan controller; gear, 1% at cruise Housing Beam PTO parameters in top gear Refuse Packer / Gear down protection; % 18% at 11-Spd 40K-46K Walking Wheel Roll-Off Idle shutdown timer; peak torque in top Manual or Allison Thick Wall Beam Diff-locks ON/OFF fan controller; gear, 1% at cruise Automatic Housing PTO parameters in top gear Refuse Transfer Gear down protection; % 18% at 15% 10/13/18-Speed 40K-46K Walking Wheel Idle shutdown timer; peak torque in top Thick Wall Beam Diff-locks ON/OFF fan controller; gear, 1% at cruise Housing PTO parameters in top gear Construction Gear down protection; % 18% at 16% 20% 10/11/13/18-Spd 40K-46K Air or Wheel Idle shutdown timer; peak torque in top Manual or Allison Thick Wall Walking Diff-locks, ON/OFF fan controller; gear, 1% at cruise Automatic Housing Beam CTIS, 6x6 PTO parameters in top gear Heavy Haul Gear down protection; % 18% at 15% 18-Spd 46K - 52K Air or Wheel 110K - 140K Idle shutdown timer; peak torque in top Tandem, Walking Diff-locks, ON/OFF fan controller; gear, 1% at cruise 58K-78K Beam Traction PTO parameters in top gear Tridem Control Heavy Haul Gear down protection; % 18% at 15% 18-Spd or 46K - 52K Air or Wheel 140K - 185K Idle shutdown timer; peak torque in top with Auxiliary Single or Walking Diff-locks, ON/OFF fan controller; gear, 1% at cruise Double Beam Traction PTO parameters in top gear Reduction Control Heavy Haul Gear down protection; % 18% at 15% 18-Spd or Planetary Air or Wheel 185K Idle shutdown timer; peak torque in top Automatic Walking Diff-locks, ON/OFF fan controller; gear, 1% at cruise with Auxiliary Beam Traction PTO parameters in top gear Control, 6x6 * In order to meet gradeability requirements, vocational cruise speed may need to be spec d at higher engine rpm. Operation on rough, soft, poorly maintained or unimproved surfaces adds 3% to the above values.

19 Kenworth sets the standard for customer satisfaction. Highest in Customer Satisfaction among Vocational Segment Class 8 Trucks. J.D. Power and Associates 2004 Heavy Duty Truck Study SM. Study based on 1,596 responses from principal maintainers of heavy duty trucks. The Vocational truck segment is defined as heavy duty trucks operating in typically rugged business environments such as construction, specialized heavy hauling, sanitation/refuse, forestry, mining, or utility services. Also included in this segment are dump trucks, concrete mixers, cranes, and other related vehicles. ISO Kenworth Truck Company, A Division of PACCAR. For more information, please call or visit your local Kenworth dealer or go to KENWORTH. The World s Best. WP-1/05