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Technical Paper

A STUDY OF DIFFERENT EGR ROUTES ON A HEAVY DUTY STOICHIOMETRIC NATURAL GAS ENGINE

2009-09-13
2009-24-0096
Exhaust gas recirculation (EGR) is a suitable strategy to optimize heavy duty natural gas (NG) engines. EGR could be utilized to have high specific power, with low thermal stress, but also to increase engine efficiency. NG fuelling permits a large flexibility in EGR system design, due to very clean engine exhaust. In this paper, three types of EGR routes have been studied. The best set up, which can introduce the highest EGR quantities, to provide the best reduction of the thermal load at rated power, was found to be a cooled low pressure EGR route. However high low pressure route (HLPR) could give the possibility to increase engine efficiency by modulating the power output in the widest un-throttled range operation.
Journal Article

Understanding Practical Limits to Heavy Truck Drag Reduction

2009-10-06
2009-01-2890
A heavy truck wind tunnel test program is currently underway at the Langley Full Scale Tunnel (LFST). Seven passive drag reducing device configurations have been evaluated on a heavy truck model with the objective of understanding the practical limits to drag reduction achievable on a modern tractor trailer through add-on devices. The configurations tested include side skirts of varying length, a full gap seal, and tapered rear panels. All configurations were evaluated over a nominal 15 degree yaw sweep to establish wind averaged drag coefficients over a broad speed range using SAE J1252. The tests were conducted by first quantifying the benefit of each individual treatment and finally looking at the combined benefit of an ideal fully treated vehicle. Results show a maximum achievable gain in wind averaged drag coefficient (65 mph) of about 31 percent for the modern conventional-cab tractor-trailer.
Journal Article

Simulation of Cooling Airflow and Surface Temperature of a Midsize Truck

2009-10-06
2009-01-2894
This paper presents a simulation of the cooling airflow and surface temperatures of a midsize truck. The simulation uses full detailed geometry of the truck. Performance of the under-hood cooling airflow is analyzed and potential design changes leading to better cooling airflow are highlighted. Surface temperature over certain under-hood part is studied. Possible optimizations using various material and configurations are proposed. It is shown that the presented simulation approach provides valuable information to evaluate cooling system and thermal protection performance. Fast design iterations can be achieved using this approach.
Journal Article

Fuel Consumption Track Tests for Tractor-Trailer Fuel Saving Technologies

2009-10-06
2009-01-2891
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.
Journal Article

Technology Breakthrough Achieves Objectives for SAE Preload Targets in Heavy Duty Wheel Ends

2009-10-06
2009-01-2887
Patents granted recently to Mr. Rode have changed the industry capability to adjust and verify wheel-end bearings on trucks. Until now it was believed1 that there was nothing available to confirm or verify the most desirable settings of preload on these bearings. The new, breakthrough invention is a tool and spindle-locking nut that permit quick and accurate wheel bearing adjustment by utilizing direct reading force measurement. Bearings can be set to either SAE recommended preloads or specific endplay settings. The author has been working on bearing adjustment methods for industrial applications for over forty years, and considers these inventions to be his most important breakthrough for solving this elusive bearing adjustment problem. Consistent wheel bearing preload adjustment was not possible before, even though it was widely known to achieve the best wheel performance as noted in SAE specification J2535 and re-affirmed in 2006 by the SAE Truck and Bus Wheel Subcommittee.
Technical Paper

Heavy Duty Off-Road Truck Exhaust System Design

2009-10-06
2009-01-2853
An important segment of power system design often left to the Original Equipment Manufacturer (OEM) is the engine exhaust system. The requirement of exhaust after treatment has increased the importance of exhaust systems to be impermeable and still retain their physical flexibility. To achieve the necessary flexibility, OEMs will often choose to incorporate an available expansion joint(s) into the exhaust system. Often, conversations with expansion joint suppliers result in the OEM having to supply vital information about the application or a vehicle to record acceleration and vibration information. Unfortunately, the cost of building low volume vehicles does not always afford the OEM with enough resources to develop a custom expansion joint for the exhaust system. As a result, it is important to understand what the proper inputs are, make a sound engineering judgment as to what the worst case magnitude may be and provide that information to different suppliers.
Technical Paper

The Lubricant Contribution to Improved Fuel Economy in Heavy Duty Diesel Engines

2009-10-06
2009-01-2856
Fuel economy of internal combustion engines played an important role for engine designers for decades. For heavy duty diesel engines, over the last 10 to 15 years however, fuel economy has in some cases been sacrificed for exhaust gas emission optimizations. Now that the industry seems to have reached the point of diminishing returns in the area of reducing diesel exhaust gas emissions, the focus is back on fuel economy. This paper addresses the impact that diesel engine lubricants can have on improving fuel economy. The evaluations discussed in this paper are based on fuel economy measurements in a standardized laboratory engine test.
Journal Article

Robust Observation of Tractor-trailer Vertical Forces Using Inverse Model and Exact Differentiator

2010-04-12
2010-01-0637
In this paper, we are interested in developing a robust tire-force estimator for heavy duty vehicles. We use a combined model of the articulated vehicle: a yaw plane model for the chassis motion and a vertical plane model for the axles. In the proposed method, we make use of the on-board available sensors to which low-cost sensors are added. In order to optimize the sensors configuration, a robust exact differentiator is used in order to obtain accelerations from the measured velocities. Once the differentiation is obtained, the model is inverted to determine the unknown input forces. The approach is validated by comparing the estimation results to those given by the software simulator prosper .
Technical Paper

Investigation of the Effect of a Humid Air System on Diesel NOx and PM Emissions of a Small Diesel Engine

2011-04-12
2011-01-0692
The effects of humid air on the performance of a naturally aspired three-cylinder diesel engine with low sulfur diesel fuel have been investigated. The additions of the humidity to intake air were performed with a variable steam generator using distilled water, where the relative humidity levels of the intake air were changed from the ambient conditions of 65% to 75% and 95% levels. The tests were performed at two approximate engine output brake horse powers (BHP) of 5.9, and 8.9. Results showed approximately 3.7% and 22.5% reduction in NOx emissions when the relative humidity of the air was increased from 65% (the ambient relative humidity) to 75% and 95% respectively. The addition of the humidity results in increases in the CO, CO₂, and particulate matter (PM), by approximately 3.7, 3.55, 14.9 percents at 5.9 BHP and 22, 2.8, and 9.3 percents at 8.9 BHP. There was no change in the brake specific fuel consumption (BSFC) at 5.9 BHP and about 2.7 increase in the BSFC at 8.9 BHP.
Technical Paper

Noise Reduction for the Bogie of Mass Rapid Train

2011-04-12
2011-01-0499
The Taipei Metro is one of the major transportation systems in the Taipei area. Noticeable noise and vibration caught attention during the train turning on a rail with a large angle. The initial investigation indicates the noise occurs between the slewing ring bearing and the friction sets which are located between the body and chassis systems. A study was conducted to identify the root causes. A lab test to duplicate the reported problem observed on the train was established, and a set of experiments were performed in the lab to identify the root causes. Under certain contact conditions, unsmooth turning would occur and cause the noise and vibration. To further identify and understand the root causes. An ADAMS multibody dynamic model which included the slew bearing and friction set was build to perform the train turn motion, and to verify the lab test. Different friction materials were also included in the simulation.
Technical Paper

Construction of a Failure Model of Spot Welds Using Lap-Shear Tests

2011-04-12
2011-01-0471
This paper proposes an alternative methodology to construct a dynamic failure model of spot welds under combined axial and shear loading conditions for auto-body crash analyses performing cross-tension tests and lap-shear tests which are substitution of pure-shear tests. To construct a failure model of a spot weld proposed by Song and Huh, failure tests of spot welds with an imposed angle to the weldment have to be carried out at an interval of 15° from 0° to 90°. In the general case, it was suggested that the β value of 1.45 from the results of the failure load of cross-tension tests and pure-shear tests can be used for constructing their failure model. However, the scheme is not practical because of difficulties in making pure-shear specimens with the same welding conditions of two-sheet spot weld because the pure-shear specimen is generally prepared with three-sheet spot weld.
Journal Article

Brain Waves Measurement Based Evaluation of Mental Workload Related to Visual Information While Driving

2011-04-12
2011-01-0593
In order to build a useful and comfortable in-car human machine interface systems, the information presentation method should be easy to understand (low mental workload) and one should be able to respond with ease to the information presented (low response workload). We are making efforts to establish an evaluation method that would differentiate between mental workload and response workload. Here, we present the results of our trial using brain waves measurements (Eye Fixation Related Potentials). We focus on the relation between P3 latencies and drivers response workload compared to mental workload in a task involving eye movements. Previous experiments showed that P3 latency correlates strongly with the amount of information presented. The current experiment shows that P3 latencies seem to be independent to the type of response the subject is requested to perform.
Technical Paper

An Exploratory Study of the Driver Workload Assessment by Brain Functional Imaging Using Onboard fNIRS

2011-04-12
2011-01-0592
In making driver workload assessments, it is important to evaluate the driver's level of brain activity because the operation of a motor vehicle presumably involves higher-order brain functions. Driving on narrow roads in particular probably imposes a load on the driver's brain functions because of the need to be cognizant of the tight space and to pay close attention to the surroundings. Test vehicles were fitted with a functional near-infrared spectroscopy (fNIRS) system for measuring bloodstream concentrations at 32 locations in the frontal lobe of the participating drivers in order to evaluate their levels of mental activity while driving on narrow roads. The results revealed significant increases in cerebral blood flow corresponding to the perceived workload. This suggests that increases in cerebral blood flow can be used as an effective index for estimating mental workloads.
Journal Article

Image Processing Method for Speed Perception with Side View Camera

2011-04-12
2011-01-0591
This paper presents a verification of the effectiveness of an image processing method, used to reduce the inconsistent speed perception caused by using the camera images in conjunction with side-view mirrors. Vision assistance technology using cameras is widely used in practical applications today. However, speed and distance perceived with camera images may differ from those viewed directly or viewed with conventional side-view mirrors. That is particularly evident in wide-angle camera images, and can easily cause a sense of discomfort experienced by the driver. A Side View Camera (SVC) shows images rearward and to the side that include the blind spots of side-view mirrors on an onboard display. It is a system to compensate side-view mirrors, broadening the driver's field of view to eliminate bind spots. SVC is used in conjunction with the side-view mirrors.
Technical Paper

Safety and Performance Benefits Associated with the Use of a Spotter Mirror: Impact on Driver Lane-Change Planning and Execution

2011-04-12
2011-01-0595
Research was conducted to assess driver acceptance and performance associated with a spotter mirror feature intended to reduce the incidence of lane-change conflicts by enhancing drivers' ability to detect vehicles in their side blind zone. The spotter mirror consisted of an integrated spherical convex blind zone mirror inset within a larger planar mirror. The spotter mirror's field-of-view was designed to target the vehicle's side blind zone area and to help drivers quickly detect the presence or absence of a vehicle in the blind zone. The study captured normative lane-change behavior during an extended drive on public roadways, with and without access to the spotter mirror system, for a sample of familiar and unfamiliar supplemental mirror users. In order to capture more naturalistic lane-change behavior, drivers were informed that the purpose of the study was to evaluate the adequacy of existing road signs for navigating to a destination.
Journal Article

Legibility: Back to the Basics

2011-04-12
2011-01-0597
The objective for this study was to revisit some of the known factors that affect legibility including font characteristics, as well as, contrast polarity, luminance contrast, and color contrast under high ambient conditions as specified in SAE J1757. The study focused on older drivers due to their increased visual needs and limitations. The study was conducted in 2 phases: 1) a study of font characteristics; character height, character width, and stroke width using a central composite design. Subjects read a group of letters and numerals displayed on a laptop display using occlusion goggles. The reading time (Total Shutter Open Time or TSOT), reading errors, and a subjective Readability Rating (using a 4 point scale "Very Easy," "Easy," "Difficult," "Very Difficult") were recorded. Licensed drivers in three age groups, 25 to 44 yrs, 45 to 59 yrs, and 61 to 91 yrs participated. The response surfaces were generated and compared to the character sizes recommended in ISO 15008.
Journal Article

An Eyellipse for Rear Seats with Fixed Seat Back Angles

2011-04-12
2011-01-0596
This paper describes the development of the fixed seat eyellipse in the October 2008 revision of SAE Recommended Practice J941. The eye locations of 23 men and women with a wide range of stature were recorded as they sat in each of three second-row bench seats in a laboratory mockup. Testing was conducted at 19-, 23-, and 27-degree seat back angles. Regression analysis demonstrated that passenger eye location was significantly affected by stature and by seat back angle. The regression results were used to develop an elliptical approximation of the distribution of adult passenger eye locations, applying a methodology previously used to develop the driver eyellipse in SAE J941-2002.
Technical Paper

Application and Performance Characteristics of Aluminum Armor Plate for the Hull Construction of Current and Future Military Tactical Vehicles

2011-04-12
2011-01-0536
The application of aluminum armor plate for military vehicles has significantly increased during the past decade. Both US Army and Marine Corps place great emphasis on lighter weight, higher agility and fuel efficiency as well as improved survivability. This requires lighter armor which makes aluminum armor plate a major structural material. Recent US ARL investigations indicate that when properly designed, aluminum armor plate can indeed provide the required level of ballistic protection at lighter weight. Consequently, in the past few years, a number of new alloys and tempers have been added to military armor plate specifications. One tactical vehicle with aluminum hull i.e. MRAP RG-33 has already been deployed and is currently operating in both Afghanistan and Iraq. Also, one of the three selected JLTV designs uses aluminum hull.
Technical Paper

Evaluation of US Rear Underride Guard Regulation for Large Trucks Using Real-World Crashes

2010-11-03
2010-22-0007
Current requirements for rear underride guards on large trucks are set by the National Highway Traffic Safety Administration in Federal Motor Vehicle Safety Standards (FMVSS) 223 and 224. The standards have been in place since 1998, but their adequacy has not been evaluated apart from two series of controlled crash tests. The current study used detailed reviews of real-world crashes from the Large Truck Crash Causation Study to assess the ability of guards that comply with certain aspects of the regulation to mitigate passenger vehicle underride. It also evaluated the dangers posed by underride of large trucks that are exempt from guard requirements. For the 115 cases meeting the inclusion criteria, coded data, case narratives, photographs, and measurements were used to examine the interaction between study vehicles. The presence and type of underride guard was determined, and its performance in mitigating underride was categorized.
Technical Paper

Exhaust Emission Characteristics of Commercial Vehicles Fuelled with Biodiesel

2010-10-25
2010-01-2276
The application of biodiesel as an alternative fuel for petroleum diesel fuel is very effective for the reduction of CO₂ emission, because biodiesel is produced from renewable biomass resources. In Japan, neat biodiesel derived from waste cooking oil has often been applied to commercial vehicles. However, it is possible that the difference of fuel properties between conventional diesel fuel and biodiesel causes the problems on exhaust emission characteristics of diesel engine. Therefore, it is necessary to clarify the effect of biodiesel fuelling on exhaust emissions from commercial vehicles. Light-duty garbage trucks and heavy-duty diesel buses which were actually fueled with biodiesel in Kyoto, Japan, were used for test vehicles in this study. The exhaust emissions from these vehicles during JE05 mode tests were compared between biodiesel derived from waste cooking oil and conventional diesel fuel.
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