Slide Number 1OverviewWho am I??Commercial VehiclesTrucking Industry – Quick FactsNorth American TruckingSlide Number 7Global IndustryTruck ApplicationsChassis ComponentsFrame BendingChassis EquipmentPowertrain - EnginesEngine ComponentsPowertrain - TorquePowertrain - TransmissionPowertrain - Gear ratiosRear AxlesRear AxlesRear AxlesRear AxlesBrakesBrakesAxle SuspensionsAxle SuspensionsTrailing arm air suspensionsParallelogram DesignsParallelogram DesignLeaf SpringsWalking BeamStatic Roll ThresholdManufacturing ProcessesManufacturing ProcessesFuel ConsumptionAlternative FuelsEnvironmental RegulationsSCRSlide Number 38Truck Information ReferencesHeavy TrucksMAE 442Spring 2009Beth HarringtonOverview• Who am I?• Commercial Vehicles• Trucking Industry• Chassis• Engine • Transmission•Axles• Brakes• Suspension • Manufacturing• Fuel Consumption and Alternative Fuels• Environmental RegulationsWho am I??• Beth Harrington• Associate Engineer for Volvo 3P– Rear Suspension Department• International Graduate Program Alumni• BSME from NCSU May 2008• MSME from NCSU EOL December 2010• Wolfpack Motorsports Baja SAE AlumniCommercial VehiclesTrucksBusesConstruction EquipmentFarm EquipmentDefense VehiclesEmergency Response VehiclesTrucking Industry – Quick Facts• In 2008, the trucking industry hauled 10.2 billion tons of freight, or 69 percent of total U.S. freight tonnage, collecting 83.1% of total transport revenue.• There are 3.5 million truck drivers in the United States Total industry employment is 8.7 million, or one of every 15 people working in the United States.• Most individual long-haul drivers average from 100,000 to 110,000 miles driving per year. Manufacturers design trucks to run 1 million miles or more. The US long-haul, heavy-duty truck transportation industry is currently experiencing a national shortage of 20,000 truck drivers.• A Class 8 truck reflects a heavy duty truck over 33,000 lbs Gross Vehicle Weight Rating.• The trucking industry is a backbone of the American society, and a key indicator of the economic situation. When the trucking industry is in trouble, so are we.North American TruckingNavistar - InternationalPaccar - Peterbilt & KenworthVolvo Group- Volvo & MackDaimler – Freightliner & Western Star• There are 4 competitive class 8 truck manufacturers in the US:Global Industry• Trucking can be found around the world, but in drastically different applications:Rough, long haul over the Australian outback.Cold and icy in CanadaTractor + trailer length regulations in EuropeTruck ApplicationsHighway• Long Haul• Heavy duty• RegionalVocational• Construction• RefuseChassis Components• Chassis – Frame Rails– The frame of a heavy truck is the backbone of the whole operation. Everything must mount to it or sit on it. It must be able to twist to varying road conditions while supporting the other truck functions.Frame Bending– The bending moment is the force acting on the frame from all the components on it as well as the input from the trailer and the road below.– The Resisting Bending Moment is the maximum load or force that the frame can support without permanent damage.RBM = S*I/CWhere RBM = resisting bending moment (in-lb)S = stress or yield point of the rail (lb/in2)I/C – Section modulus (in3)• Fuel Tanks• Exhaust equipment• After treatment• Fifth Wheels• Mudflaps• Battery Boxes• Back of Cab Access• Steps• Deck platesChassis EquipmentPowertrain - Engines• Diesel engines – I assume you all know about the diesel engines and if not you can Wikipedia it! The standard sizes for heavy duty diesel engines ranges from 11 liters to 16 liters. • Fuel economy and Power are both extremely important in the trucking industry. Unfortunately these don’t normally go together…Engine Components• Engine Block– Cylinders– Valves– Pistons– Crankshaft– Flywheel housing and oil pan– Timing gears– Overhead Camshaft– Oil system– Fuel injection system• Air intake and exhaust– Turbocharger– Intercooler• Cooling systemPowertrain - Torque• To find a happy median, these diesel engines are high torque. This means that we can increase performance and better fuel economy through a high torque rise.Torque rise is the difference between torque at rated speed and peak torque expressed as a percentage of torque at the rated speed.%100Speed Ratedat TorqueRise Torquein Difference (%) Rise Torque ×=Example:Peak Torque Rise = 1500 lb-ftTorque at Rated Speed = 1300 lb-ft% Torque Rise = (1500-1300)/1300 x100Torque Rise = 15%Powertrain - Transmission• The transmission and rear axle(s) provide the necessary gear ratios to effectively utilize engine power. We want to obtain the most efficient working range, which encompasses maximum horsepower produced per gallon of fuel consumed.Powertrain - Gear ratios• Selection of gear ratios by mating transmission and rear axle:– Important points to remember:» Use past experience!» Gear ratios should be numerically fast enough to assure desired speed for highway operation. Top speed should be approximately 5-10 mph faster than cruising speed or about 90% of governed speed. » Gear ratios should be numerically slow enough to provide maximum grade performance with lowest gear combinations and maximum start-ability under all operating conditions. Overall gear reduction = Main Transmission Ratio x Aux. Transmission Ratio x Drive Axle RatioRear Axles– Rear axles on a truck are the drive axles, while front axles are steer axles. It is possible to get up to 3 of either, although it makes one funny looking truck! – To decide which rear axle you need you must look at:– Gross weight of combination• Type of terrain• Road speed• Tire size• Axle ratio required• Transmission ratios• Engine torque• Engine speed• MaintenanceRear Axles– Rear axles may be classified as follows:• The ‘dead’ axle carries the required load only. If the axle is in front of the drive axles, it is known as a pusher, and if it is behind, it is known as a tag. • The ‘live’ axle includes all necessary gears and parts for the transmission of power as well as facility for carrying the required load.– When looking at the live axle, we classify according to gear drive. Examples:» Straight bevel gear » Hypoid gear – has more tooth contact than a straight bevel and therefore is stronger and quieter» Double reduction – provides greater