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The objective of the project was to conduct controlled test-track studies of solutions for achieving higher fuel efficiency and lower greenhouse gas emissions in the trucking industry. Using vehicles from five Canadian fleets, technologies from 12 suppliers were chosen for testing, including aerodynamic devices and low rolling resistance tires. The participating fleets also decided to conduct tests for evaluating the impact on fuel consumption of vehicle speed, close-following between vehicles, and lifting trailer axles on unloaded B-trains. Other tests targeted comparisons between trans-container road-trains and van semi-trailers road-trains, between curtain-sided semi-trailers, trans-containers and van semi-trailers, and between tractors pulling logging semi-trailers loaded with tree-length wood and short wood. The impact of a heavy-duty bumper on fuel consumption and the influence of B5 biodiesel blend on fuel consumption were also assessed.

The objective of this study was to evaluate the concept of a heavy-duty tractor - motorized semi-trailer hybrid electric combination, which would have electric drive axles on the semi-trailer. The scope of the project included an analysis of the general concept of a power-driven semi-trailer, the positioning of the concept of the heavy-duty tractor - motorized semi-trailer hybrid electric combination in the general context of the technology, and the evaluation of the applicability of the concept for different duty cycles. Several transport activities were analyzed to determine specific duty cycles for heavy-duty vehicles: highway line haul and regional haul, construction haul, and off-highway hauling of raw materials, such as forestry transport with Class 8 and off-highway tractor-trailer combinations.

The objective of this project was to compare the fuel consumption and traction performances of 6 × 2 and 6 × 4 Class 8 tractors. Two approaches have been considered: evaluation of 6 × 2 tractors, modified from 6 × 4 tractors, and evaluation of OEM 6 × 2 tractors. Compared to the 6 × 4 tractors, which are equipped with a rear tandem with both drive axles, the 6 × 2 tractors have a rear tandem axle with one drive axle, and one non-drive axle, also called dead axle. The 6 × 2 tractor configurations are available from the majority of Class 8 tractor manufacturers. The SAE Fuel Consumption Test Procedures Type II (J1321) and Type III (J1526) were used for fuel consumption track test evaluations. Traction performances were assessed using pull sled tests to compare pulling distance, maximum speed, and acceleration when pulling the same set sled on similar surface.

The performance of several aerodynamic technologies and approaches, such as trailer skirts, trailer boat tails, gap reduction, was evaluated using track testing, model wind tunnel testing, and CFD simulation, in order to assess the influence of the design, position and combination of various aerodynamic devices. The track test procedure followed the SAE J1321 SAE Fuel Consumption Test Procedure - Type II. Scale model wind tunnel tests were conducted to have direct performance comparisons among several possible configurations. The wind tunnel tests were conducted on a 1/8 scale model of a tractor in combination with a 53-foot semi-trailer. Among others, the wind tunnel tests and CFD simulations confirmed the influences of trailer skirts' length observed during the track tests and that the wider skirt closer to the ground offer better results. The differences in the shape, dimensions and position of rear deflectors and trailer skirts on the trailer are reflected in the test results.

A truck platooning system was tested using two heavy-duty tractor-trailer trucks on a closed test track to investigate the sensitivity of intentional lateral offsets over a range of intervehicle spacings. The fuel consumption for both trucks in the platoon was measured using the SAE J1321 gravimetric procedure while travelling at 65 mph and loaded to a gross weight of 65,000 lb. In addition, the SAE J1939 instantaneous fuel rate was calibrated against the gravimetric measurements and used as proxy for additional analyses. The testing campaign demonstrated the effects of intervehicle gaps, following-vehicle longitudinal control, and manual lateral control. The new results are compared to previous truck-platooning studies to reinforce the value of the new information and demonstrate similarity to past trends. Fuel savings for the following vehicle was observed to exceed 10% at closer following distances.

The purpose of this study was to evaluate automatic transmissions in a forestry context by comparing their performance with that of standard manual transmissions, and assessing the possibility of improving fuel efficiency by adapting the engine and automatic transmission performances to the vehicle's load. Long-haul test results showed that during the test day, the degradation in driver performance with the manual transmission truck translated into a 2.9% relative increase in fuel consumption when compared with the automatic transmission truck. The fleet data assessment indicated no obvious difference in fuel consumption between the performance of automatic transmissions and manual transmissions. One system for adapting engine performance to vehicle load uses an onboard weigh scale to determine the load status of the vehicle.

Air resistance, after gross vehicle weight, is the largest factor responsible for vehicle energy loss and has an important influence on fuel consumption. The magnitude of aerodynamic drag is affected by the vehicle's shape, frontal area, and travel speed. This study aimed to evaluate several aerodynamic drag reduction measures applicable to class 8 tractor-trailer combinations. The tested aerodynamic devices included trailer aft body rear deflectors (boat tails), trailer skirts, gap deflectors, fuel tank fairings and truck rear-axle fenders. It also assessed the aerodynamic influence of opened doors on an empty wood chip van trailer on the fuel consumption of the tractor-trailer combination. The tests were conducted according to SAE J1321 Joint TMC/SAE Fuel Consumption Test Procedure - Type II.

This study aimed to evaluate several rolling resistance reduction measures applicable to class 8 tractor-trailer combinations. Two methods have been employed: fuel consumption tests according to the SAE J1321 Joint TMC/SAE Fuel Consumption Test Procedure - Type II, and long-term operational observations using control and test vehicles monitored throughout baseline and test periods. One way to reduce the rolling resistance is to use wide-base tires: two different Type II fuel consumption tests revealed a more than 9 % improvement in fuel economy for a tractor-trailer combination equipped with wide-base tires. Long-term operational observation assessed the use of single wide-base tires on two 8-axle B-train tractor-trailer combinations. The results showed an average 5.11% fuel improvement and an average 4.37% energy intensity improvement. Other tests compared single-wide base tires with different tread patterns and tire compounds.

The objective of this project was to provide pertinent information on the performance of refrigeration and heating transportation units to help fleets make decisions that will improve efficiency and increase productivity. To achieve this objective, tests were designed to measure the performance of selected refrigeration and heating units, mounted on refrigerated and heated van semitrailers. Cooling and freezing tests were carried out in summer conditions while heating tests were carried out in winter conditions, for various temperature settings. Two fundamental approaches were considered: the design of the refrigerated or heated trailer and the temperature setting of the refrigeration or heating unit. For cooling and freezing tests, the fuel consumption comparison between similar trailer models of different ages showed that newer units performed better than older ones.

This project's objective was the development of an on-road vehicle fuel consumption test procedure for representative stop-and-go urban duty cycles. The scope of the project included a review of existing stop-and-go urban duty cycles, the development of a track testing methodology for measuring the fuel consumption on stop-and-go urban duty cycles, and testing with a view to the validation of the methodology. Literature review analyzed several transport activities to determine specific stop-and-go urban duty cycles, such as pick-up and delivery operations, refuse collection, bus transport, and utility and service operation. It was found that driving cycles should be easy enough to recreate and replicate on the test track and should be representative of application driving patterns. The cycles should be adapted for fuel economy testing, and geometric cycles are easier to follow than the cycles based on actual drive traces.

The authors present transient wind velocity measurements from two successive, well-documented truck platooning track-test campaigns to assess the wake-shedding behavior experienced by trucks in various platoon formations. Utilizing advanced analytics of data from fast-response (100-200-Hz) multi-hole pressure probes, this analysis examines aerodynamic flow features and their relationship to energy savings during close-following platoon formations. Applying Spectral analysis to the wind velocity signals, we identify the frequency content and vortex-shedding behavior from a forward truck trailer, which dominates the flow field encountered by the downstream trucks. The changes in dominant wake-shedding frequencies correlate with changes to the lead and follower truck fuel savings at short separation distances.

The conditions of vehicle use are among the most important factors affecting the fuel consumption. Such conditions may include payload, type of duty cycle, traffic density, number of stops and starts, type of pavement, and use of auxiliary systems. Transport companies are interested in results from experiments reproducing similar operational conditions to help them understand and quantify the impact of duty cycles on fuel economy and operating costs. The goal of this study was to evaluate the effect of driving cycle on fuel efficiency. The fuel consumption measurement methodology was based on the protocols described in SAE J1321 Fuel Consumption Test Procedure - Type II and SAE J1526 Fuel Consumption Test Procedure (Engineering Method). The tests were conducted with various vehicles under different test conditions. Several duty cycles were replicated on the track, such as a local delivery, regional transport, long-distance constant speed, and stop-and-go cycles.

The objectives of this project were to evaluate the reduction in fuel consumption and greenhouse gas (GHG) emissions made possible by hybrid technology, and to identify good driving habits with this type of vehicle. Two diesel-electric hybrid pick-up and delivery trucks and one diesel-electric hybrid utility vehicle equipped with an electric driven PTO (power take-off) system were included in the project. The first phase was the evaluation in actual operating conditions. Onboard computers were installed in the vehicles to record parameters that make it possible to determine driving habits. Based on operational data, specific duty cycles were built and track tests were conducted to measure the fuel consumption on these duty cycles. It was therefore possible to compare the hybrid trucks with other diesel trucks featuring similar characteristics. The delivery hybrid trucks showed up to 34% fuel savings during the track tests.

Commercial fleets are interested in results from experiments conducted in real operational conditions to help them quantify and understand the impact of environmental factors on fuel economy and operating costs. The goal of this study was to measure through controlled track testing and operational testing the effects of environmental conditions, particularly ambient temperature, and air density, on fuel consumption. Extensive track testing based on the SAE J1321 Fuel Consumption Test Procedure - Type II protocol with various vehicles under different test conditions showed a decrease in fuel efficiency of up to 12% for an air density variation of 7% and an ambient temperature variation of 30 °F (17 °C). Data from various and extensive operational tests were also analyzed, specifically from tests conducted using several groups of medium and heavy-duty vehicles involved in regional, local, urban transport and pick-up and delivery.

An integrated adaptive cruise control (ACC) and cooperative ACC (CACC) was implemented and tested on three heavy-duty tractor-trailer trucks on a closed test track. The first truck was always in ACC mode, and the followers were in CACC mode using wireless vehicle-vehicle communication to augment their radar sensor data to enable safe and accurate vehicle following at short gaps. The fuel consumption for each truck in the CACC string was measured using the SAE J1321 procedure while travelling at 65 mph and loaded to a gross weight of 65,000 lb, demonstrating the effects of: inter-vehicle gaps (ranging from 3.0 s or 87 m to 0.14 s or 4 m, covering a much wider range than previously reported tests), cut-in and cut-out maneuvers by other vehicles, speed variations, the use of mismatched vehicles (standard trailers mixed with aerodynamic trailers with boat tails and side skirts), and the presence of a passenger vehicle ahead of the platoon.

Conventional assessments of the aerodynamic performance of ground vehicles have, to date, been considered in the context of a vehicle that encounters a uniform wind field in the absence of surrounding traffic. Recent vehicle-platooning studies have revealed measurable fuel savings when following other vehicles at inter-vehicle distances experienced in every-day traffic. These energy savings have been attributed in large part to the air-wakes of the leading vehicles. This set of three papers documents a study to examine the near-to-far regions of ground-vehicle wakes (one to ten vehicle lengths), in the context of their potential influence on other vehicles. Part two of this three-part paper documents the influence of the ambient winds on the development of the wake behind a vehicle.

Conventional assessments of the aerodynamic performance of ground vehicles have, to date, been considered in the context of a vehicle that encounters a uniform wind field in the absence of surrounding traffic. Recent vehicle-platooning studies have revealed measurable fuel savings when following other vehicles at inter-vehicle distances experienced in every-day traffic. These energy savings have been attributed in large part to the air-wakes of the leading vehicles. This set of three papers documents a study to examine the moderate-to-far regions of ground-vehicle wakes (one to ten vehicle lengths), in the context of their potential influence on other vehicles. Part Three of this three-part paper documents the wake characteristics for multi-vehicle scenarios of two or three vehicles, in single-lane or two-lane arrangements.

Conventional assessments of the aerodynamic performance of ground vehicles have, to date, been considered in the context of a vehicle that encounters a uniform wind field in the absence of surrounding traffic. Recent vehicle-platooning studies have revealed measurable fuel savings when following other vehicles at inter-vehicle distances experienced in every-day traffic. These energy savings have been attributed in large part to the air-wakes of the leading vehicles. This set of three papers documents a study to examine the near-to-far regions of ground-vehicle wakes (one to ten vehicle lengths), in the context of their potential influence on other vehicles. Part one of this three-part paper documents principally the influence of vehicle shape on the development of its wake.