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Heavy duty truck engines are quite difficult to electrify, due to the large amount of energy required on-board, in order to achieve a range comparable to that of diesels. This paper considers a commercial 6-cylinder engine with a displacement of 12.8 L, developed in two different versions. As a standard diesel, the engine is able to deliver more than 420 kW at 1800 rpm, whereas in the CNG configuration the maximum power output is 330 kW at 1800 rpm. Maintaining the same combustion chamber design of the last version, a theoretical study is carried out in order to run the engine on Hydrogen, compressed at 700 bar. The study is based on GT-Power simulations, adopting a predictive combustion model, calibrated with experimental results. The study shows that the implementation of a combustion system running on lean mixtures of Hydrogen, permits to cancel the emissions of CO2, while maintaining the same power output of the CNG engine.

The National Institute for Occupational Safety and Health (NIOSH), in cooperation with the Canadian Forces Health Services Group Headquarters, U.S. Army Tank-Automotive and Armaments Command (TACOM), and the Ministry of Health & Long-Term Care, Ontario (Canada), conducted a test program to evaluate the capability of mobile restraint systems to protect occupants in the patient compartment of an ambulance. This paper focuses on the vehicle chassis behavior and acceleration pulses as seen in each test conducted to support the program. This program consisted of testing one Type I ambulance mounted on a Ford F-350 truck chassis (1994 vintage), and three Type III ambulances mounted on Ford E-350 van chassis (two 1993, and one 1999 vintage). A vehicle-to-vehicle side impact test was conducted using the Type I ambulance with a targeted change in velocity of 27.4 kph (17 mph). A 1984 Chevrolet Sierra 2500 was the impacting vehicle for the side test.

Understanding the complex and dynamic nature of wheel-loader's operation requires a detailed system model. This paper describes the development of a conventional wheel-loader's system model that can be used to evaluate the transient response. The model includes engine details such as a mean value engine model, which takes into account turbocharger dynamics and engine governor controller. This allows the model to predict realistic performance and fuel consumption over a drive cycle. The wheel-loader machine is modeled in LMS Amesim® and the engine governor controller is modeled in Matlab/SIMULINK®. In order to simplify the model, hydraulic loads from the boom / bucket mechanism, steering and cooling fan are modeled as hydraulic load inputs obtained from typical short V-drive cycle. Critical wheel-loader drive cycle inputs into the model have been obtained from testing and have been used to validate the system response and cycle fuel consumption.

Mixture formation in a hydrogen-fueled heavy-duty engine with direct injection and a nearly-quiescent top-hat combustion chamber was investigated using laser-induced fluorescence imaging, with 1,4-difluorobenzene serving as a fluorescent tracer seeded into hydrogen. The engine was motored at 1200 rpm, 1.0 bar intake pressure, and 335 K intake temperature. An outward opening medium-pressure hollow-cone injector was operated at two different injection pressures and five different injection timings from early injection during the intake stroke to late injection towards the end of compression stroke. Fuel fumigation upstream of the intake provided a well-mixed reference case for image calibration. This paper presents the evolution of in-cylinder equivalence ratio distribution evaluated during the injection event itself for the cylinder-axis plane and during the compression stroke at different positions of the light sheet within the swirl plane.

This study aimed to construct driver models for overtaking behavior using long short-term memory (LSTM). During the overtaking maneuver, an ego vehicle changes lanes to the overtaking lane while paying attention to both the preceding vehicle in the travel lane and the following vehicle in the overtaking lane and returns to the travel lane after overtaking the preceding vehicle in the travel lane. This scenario was segregated into four phases in this study: Car-Following, Lane-Change-1, Overtaking, and Lane-Change-2. In the Car-Following phase, the ego vehicle follows the preceding vehicle in the travel lane. Meanwhile, in the Lane-Change-1 phase, the ego vehicle changes from the travel lane to the overtaking lane. Overtaking is the phase in which the ego vehicle in the overtaking lane overtakes the preceding vehicle in the travel lane.

Reconstruction of inline crashes between vehicles with a low closing speed, so-called “low speed” crashes, continues to be a class of vehicle collisions that reconstructionists require specific methods to handle. In general, these collisions tend to be difficult to reconstruct due primarily to the lack of, or limited amount of, physical evidence available after the crash. Traditional reconstruction methods such as impulse-momentum (non-residual damage based) and CRASH3 (residual damage based) both are formulated without considering tire forces of the vehicles. These forces can be important in this class of collisions. Additionally, the CRASH3 method depends on the use of stiffness coefficients for the vehicles obtained from high-speed crash tests. The question of the applicability of these (high-speed) stiffness coefficients to collisions producing significantly less deformation than experimental crashes on which they are generated, raises questions of the applicability.

An innovative Power Line Carrier (PLC) Communication system for video and digitally signal processed data distribution using the existing DC copper wire is presented. The major contribution consists of a new signal coupler that achieves a stable transmission bandwidth on the DC electrical lines. Several weeks of continuous beta tests achieved video transmission on the trucks +12V wiring (from the back of the truck to the driver's cabinet) and product manufacturing and delivery has started. Benefits include: simplicity of application; ease of implementation; effectiveness with video and data; applicability to all application types; elimination of coax and twisted pair wiring and its maintenance.

The Daimler Detroit AssuranceⓇ 4.0 collision mitigation system is able to assist a driver in various aspects of safely operating their vehicle. One capability is the Active Brake Assist (ABA), which uses the Video Radar Decision Unit (VRDU) to communicate with the front bumper-mounted radar to provide information about potential hazards to the driver. The VRDU may warn the driver of potential hazards and apply partial or full braking, depending on the data being gathered and analyzed. The VRDU also records event data when an ABA event occurs. This data may be extracted from the VRDU using Detroit DiagnosticLink software. This paper presents an overview of the VRDU functionality and examines aspects of VRDU data such as the range and resolution of data elements, the synchronicity or timing of the recorded data, and application of the data for use in the analysis of crashes.

Modern heavy vehicles may be equipped with an Advanced Driver Assistance System (ADAS) designed to increase highway safety. Depending on the vehicle or manufacturer, these systems may detect objects in a driver’s blind spot, provide an alert when the ADAS determines that the vehicle is leaving its lane of travel without the use of a turn signal, or notify the driver when certain road signs are detected. ADASs also include adaptive cruise control, which adjusts the vehicle’s set cruise speed to maintain a safe following distance when a slower vehicle is detected ahead of the truck. In addition, the ADAS may have a Collision Mitigation System (CMS) component that is designed to help drivers respond to roadway situations and reduce the severity of crashes. CMSs typically use radar or a combination of radar and optical technologies to detect objects such as vehicles or pedestrians in the vehicle’s path.

Lean-burn hydrogen internal combustion engines are a good option for future transportation solutions since they do not emit carbon-dioxide and unburned hydro-carbons, and the emissions of nitric-oxides (NOx) can be kept low. However, under lean-burn conditions the combustion duration increases, and the combustion stability decreases, leading to a reduced thermal efficiency. Turbulent jet ignition (TJI) can be used to extend the lean-burn limit, while decreasing the combustion duration and improving combustion stability. The objective of this paper is to investigate the feasibility of a passive pre-chamber TJI system on a heavy-duty hydrogen engine under lean-burn conditions using CFD modelling. The studied concept is mono-fuel, port-fuel injected, and spark ignited in the pre-chamber. The overall design of the pre-chamber is discussed and the effect of design parameters on the engine performance are studied.

Over the years, natural gas has been promoted as a clean-burning fuel, especially for transit buses. A decade ago one could claim that natural gas buses deliver significant emission benefits over diesel buses, especially regarding particulate emissions. The spread in nitrogen oxide emissions has always been significant for natural gas engines, high for lean-burn engines and low for three-way catalyst equipped stoichiometric engines. With the introduction of US 2010 and Euro VI (effective as of 2014) exhaust emission regulations, independent of the fuel, the regulated emissions of all engines have been brought close to zero level. This means that the advantage of natural gas as a clean fuel is diminishing, especially in a situation in which electric transit buses are also entering the market. The motivation to use natural gas could still be diesel fuel substitution and to some extent, also reduction of greenhouse gas emissions.

The purpose of this study was to determine if quasi-static (QS) bumper force-deformation (F-D) data could be used in a low-speed bumper-to-bumper simulation model (1) in order to reconstruct low-speed crashes. In the simulation model, the bumpers that make contact in a crash are treated as a system. A bumper system is defined as the two bumpers that interact in a crash positioned in their orientation at the time of the crash. A device was built that quasi-statically crushes the bumpers of a bumper system into each other and measures the compression force and the deformation of the bumper system. Three bumper systems were evaluated. Two QS F-D measurements were performed for each bumper system in order to demonstrate the repeatability of the QS F-D measurement. These measurements had a compression phase and a rebound phase. A series of crash tests were performed using each bumper system.

This paper presents an analysis on the position of driver eye height as a function of their standing height, weight, biological sex, seat back angle and seat bottom angle. Typically, eye heights are estimated based on standing height, or measured from a rigid seated position with a vertical seat back. While reasonably close, these estimated eye heights are generally not correct for individuals seated in deformable vehicle seats with non-vertical seat back angles. Thus, these measurements tend to overestimate the participants eye height in more ecologically probable scenarios, such as driver eye height while operating a vehicle. In this study, eye measurements were taken from a standing position and while seated on a rigid surface and then compared to the same participant’s eye height measured while seated on six different representative vehicle seats with seat back angles of 20, 25, and 30 degrees respectively.

The emissions of two ultralow NOx heavy-duty (HD) vehicles equipped with 0.02 g/bhp-hr low NOx natural gas (NG) engines were evaluated on a chassis dynamometer. This included a waste hauler and a city transit bus, each with a 0.02 g/bhp-hr NOx L9N near zero (NZ) natural gas engine. The vehicles were tested over a variety of different cycles, including the Urban Dynamometer Driving Schedule (UDDS), port drayage cycles, transit bus cycles, and a refuse truck cycle. For both vehicles, the NOx emissions results were below the 0.02 g/bhp-hr level for most cycles, with the exception of some cold start tests. For the waste hauler, NOx emissions averaged between 0.014 and 0.002 g/bhp-hr for the hot start tests, and from 0.043 to 0.014 g/bhp-hr for the cold start tests. This represented NOx emissions reductions from 97%-100% of compared with previous ISL G 8.9 engines.

A novel predictable tire model has been proposed for combined braking and cornering forces, which is based on only a few pure baking and pure cornering tests. It avoids elaborate testing of all kinds of combinations of braking and side forces, which are always expensive and time consuming. It is especially important for truck or other large size tires due to the capability constraints of tire testing facilities for combined shear forces tests. In this paper, the predictive model is based on the concept of slip circle and state stiffness method. The slip circle concept has been used in the COMBINATOR model to obtain the magnitude of the resultant force under combined slip conditions; however the direction assumption used in the COMBINATOR is not suitable for anisotropic tire slip stiffness.

In this paper a tire model for describing tire turn slip properties is derived. The tread of the contact patch is divided into many massless elastic elements in both the length and width direction. Carcass deformation is expressed by the translation, bending and twisting function. A turn slip tire model is derived by analyzing the geometric relationships among the deformation of contact patch, tread and carcass. The model is validated by experimental results of parking maneuver. The model seems capable of generating transient and steady state forces and moments for turn slip, and showing varied trend of tire force according to different turn slip velocity. It could not only describe the tread deformation, but also analyze how the tread deformation affects the tire force and moment properties.

The tire mechanics characteristics are essential for analysis, simulation and control of vehicle dynamics. This paper develops the UniTire model for tire forces and moments under combined slip conditions with anisotropic tire slip stiffness. The anisotropy of tire slip stiffness, which means the difference of tire longitudinal slip stiffness and cornering stiffness, will cause that the direction of tire resultant shear stress in adhesion region is different from that in sliding region. Eventually the tire forces and moments under combined slip conditions will be influenced obviously. The author has proposed a “direction factor” before to modify the direction of resultant force in the tire-road contact patch, which can describe tire forces at cornering/braking combination accurately. However, the aligning moments which are very complicated under combined slip conditions are not considered in previous analysis.