Refine Your Search

Search Results

Viewing 1 to 7 of 7
Technical Paper

Field Test Experience of a Combined DPF and Urea-SCR System Achieving EPA'07 Emission Levels

On-road emission measurements of 23 VN-trucks on a randomly chosen driving cycle, consisting of 10 miles two-lane and 8 miles four-lane road, showed tailpipe NOx emissions on fleet average of 0.96 g/bhp-hr, or 1.06 g/bhp-hr when including the time the exhaust gas temperature was below 200°C. Complementary measurements in a SET-cycle (13 point OICA -cycle) on a chassis dynamometer showed a tailpipe emission of 0.008 g PM per bhp-hr. Moreover, cost analysis show that the diesel fuel consumption remains unchanged whether the truck running on ULSD is equipped with a Combined Exhaust gas AfterTreatment System (CEATS) installed or not.
Technical Paper

Parametric Study of Leveling System Characteristics on Roll Stability of Trailing Arm Air Suspension for Heavy Trucks

A large percentage of on-highway tractors today have air suspensions. Air suspensions require some type of control system to adjust the ride height. This system is usually referred to as a Load Leveling System. These systems come in a variety of different configurations but all basically have the same functions. When designed correctly, the system can reduce driveline vibration, reduce air consumption (improving compressor life and fuel efficiency), provide an accurate 5th wheel height and improve the ride quality. This paper explores how the characteristics of the leveling system affect the roll stability. One and Two-valve systems are considered, as well as, the position of the valve, response times, valve deadband and the systems response to an off-center load. Notably not every conceivable condition has been considered.
Journal Article

Aerodynamic Optimization of Trailer Add-On Devices Fully- and Partially-Skirted Trailer Configurations

As part of the United States Department of Energy's SuperTruck program, Volvo Trucks and its partners were tasked with demonstrating 50% improvement in overall freight efficiency for a tractor-trailer, relative to a best in class 2009 model year truck. This necessitated that significant gains be made in reducing aerodynamic drag of the tractor-trailer system, so trailer side-skirts and a trailer boat-tail were employed. A Lattice-Boltzmann based simulation method was used in conjunction with a Kriging Response Surface optimization process in order to efficiently describe a design space of seven independent parameters relating to boat-tail and side-skirt dimensions, and to find an optimal configuration. Part 1 concerns a fully-skirted tractor-trailer system, and consists of an initial phase of optimization, followed by a mid-project re-evaluation of constraints, and an additional period of optimization.
Journal Article

Combined Analysis of Cooling Airflow and Aerodynamic Drag for a Class 8 Tractor Trailer Combination

Long haul tractor design in the future will be challenged by freight efficiency standards and emission legislations. Along with any improvements in aerodynamics, this will also require additional cooling capacity to handle the increased heat rejection from next generation engines, waste heat recovery and exhaust gas recirculation systems. Fan engagement will also have to be minimized under highway conditions to maximize fuel economy. These seemingly contradictory requirements will require design optimization via analysis techniques capable of predicting both the aerodynamic drag and engine cooling airflow accurately. This study builds on previous work [1] using a Lattice Boltzmann based computational method on a Volvo VNL tractor trailer combination. Simulation results are compared to tests conducted at National Research Council (NRC) Canada's wind tunnel.
Technical Paper

Aerodynamic Study of a Production Tractor Trailer Combination using Simulation and Wind Tunnel Methods

The importance of fuel economy and emission standards has increased rapidly with high fuel costs and new environmental regulations. This requires analysis techniques capable of designing the next generation long-haul truck to improve both fuel efficiency and cooling. In particular, it is important to have a predictive design tool to assess how exterior design changes impact aerodynamic performance. This study evaluates the use of a Lattice Boltzmann based numerical simulation and the National Research Council (NRC) Canada's wind tunnel to assess aerodynamic drag on a production Volvo VNL tractor-trailer combination. Comparisons are made between the wind tunnel and simulation to understand the influence of wind tunnel conditions on truck aerodynamic performance. The production VNL testing includes a full range of yaw angles to demonstrate the influence of cross wind on aerodynamic drag.
Technical Paper

Optimized Rigid Side Underride Protection Device Designs for Tractor-Trailers and Straight Trucks

This work describes the design and testing of side underride protection devices (SUPD) for tractor-trailers and straight trucks. Its goal is to reduce the incompatibility between small passenger cars and these large vehicles during side collisions. The purpose of these crash attenuating guards is to minimize occupant injury and passenger compartment intrusion. The methods presented utilize a regulation previously created and published for testing the effectiveness of these devices based on the principles of a force application device already implemented in the Canadian rear underride guard regulation. Topology and multi-objective optimization design processes are outlined using a proposed design road map to create the most feasible SUPD. The test vehicle in question is a 2010 Toyota Yaris which represents the 1100C class of vehicle from the Manual for Assessing Safety Hardware (MASH).
Technical Paper

Evaluating a Heavy-Duty Truck Climate Control System Using Thermal Comfort-Focused Testing and Simulation Techniques

A test protocol previously developed for automotive applications was adapted to evaluate the performance of a climate control system for a heavy-duty truck. Human subjects, as well as a test system composed of a high-resolution passive sensor manikin and a human thermal model, were employed to evaluate thermal comfort perception. Testing was performed in a climate-controlled wind tunnel equipped with a dynamometer. The truck’s HVAC system performance was evaluated in a −10 °C environment. Additionally, the test protocol was designed to explore a large range of thermal sensation and comfort states. Subjective responses, including thermal sensation and comfort, as well as thermo-physiological state information, quantified by skin temperatures measured across the body, were obtained from the human test participants and compared to that which was indicated by the test system.