Search Results

Commercial vehicles require fast aftertreatment heat-up to move the SCR catalyst into the most efficient temperature range to meet upcoming NOX regulations while minimizing CO2. The focus of this paper is to identify the technology levers when used independently and also together for the purpose of NOX and CO2 reduction toward achieving 2027 emissions levels while remaining CO2 neutral or better. A series of independent levers including cylinder deactivation, LO-SCR, electric aftertreatment heating and fuel burner technologies were explored. All fell short for meeting the 2027 CARB transient emission targets when used independently. However, the combinations of two of these levers were shown to approach the goal of transient emissions with one configuration meeting the requirement. Finally, the combination of three independent levers were shown to achieve 40% margin for meeting 2027 transient NOx emissions while remaining CO2 neutral.

Practical direct injection hydrogen combustion applications typically require operating the engine in the lean regime. Lean hydrogen flames feature strong thermo-diffusive instability effects making 3D CFD simulations challenging. In particular where the calibrated model is required to operate across a range of equivalence ratios without adjustment and provide accurate results on coarse grids necessitated by the run-times of 3D CFD. In this paper we present a 3D CFD study of a Euro VI HD diesel engine converted to operate on hydrogen gas using direct injection. A scaling methodology recently proposed for conversion from constrained to freely propagating flame based on DNS data is implemented. A laminar flame speed tabulation is developed based on the conversion of 1D results obtained from direct kinetics simulations to freely propagating flame expression considering the behaviour of the thermo-diffusive instability for a wide range of pressures, temperatures and equivalence ratios.

In marine or stationary engines, consistent engine performance must be guaranteed for long-haul operations. A dual-fuel combustion strategy was used to reduce the emissions of particulates and nitrogen oxides in marine engines. However, in this case, the combustion stability was highly affected by environmental factors. To ensure consistent engine performance, the in-cylinder pressure measured by piezoelectric pressure sensors is generally measured to analyze combustion characteristics. However, the vulnerability to thermal drift and breakage of sensors leads to additional maintenance costs. Therefore, an indirect measurement via a reconstruction model of the in-cylinder pressure from engine block vibrations was developed. The in-cylinder pressure variation is directly related to the block vibration; however, numerous noise sources exist (such as, valve impact, piston slap, and air flowage).

Video from dash or surveillance cameras is sometimes used in vehicle accident reconstruction to analyze the speeds of vehicles. However, video captured during nighttime, during poor visibility conditions, or of events out of frame may not always visually capture details needed to determine the speed of the vehicle in question. Prior research has determined speed from vehicle acoustic signals, but little research has analyzed the audio portion of dash camera video for use in accident reconstruction and other forensic settings. The purpose of this study was to outline and test the validity of a method for using the audio portion of dash camera video to determine vehicle speed. Extracting the audio portion from the video recording and further processing it with commercially available software can allow the calculation of vehicle speed and acceleration when traveling over roadway surfaces and detection of turn signal activations while driving.

Apple’s mobile phone LiDAR capabilities were previously evaluated to obtain geometry from multiple exemplar vehicles, but results were inconsistent and less accurate than traditional ground-based LiDAR (SAE Technical Paper 2022-01-0832. Miller, Hashemian, Gillihan, Helms). This paper builds upon existing research by utilizing the newest version of the mobile LiDAR hardware and software previously studied, as well as evaluating additional objects of varying sizes and a newly released software not yet studied. To better explore the accuracy achievable with Apple mobile phone LiDAR, multiple objects with varied surface textures, colors, and sizes were scanned. These objects included exemplar passenger vehicles (including a motorcycle), a fuel tank, and a spare tire mounted on a chrome wheel. To test the repeatability of the presented methodologies, four participants scanned each object multiple times and created three individual data sets per software.

This study focused on occupant responses in very large pickup trucks in rollovers and was conducted in three phases. Phase 1 - Field data analysis: In a prior study [9], 1998 to 2020 FARS data were analyzed; Pickup truck drivers with fatality were 7.4 kg heavier and 4.6 cm taller than passenger car drivers. Most pickup truck drivers were males. Phase 1 extended the study by focusing on the drivers of very large pickup trucks. The size of 1999-2016 Ford F-250 and F-350 drivers involved in fatal crashes was analyzed by age and sex. More than 90% of drivers were males. The average male driver was 179.5 ± 7.5 cm tall and weighed 89.6 ± 18.4 kg. Phase 2 – Surrogate study: Twenty-nine male surrogates were selected to represent the average size of male drivers of F-250 and F-350s involved in fatal crashes. On average, the volunteers weighed 88.6 ± 5.2 kg and were 180.0 ± 3.2 cm tall with a 95.2 ± 2.2 cm seated height.

The electric vehicle (EV) is one means of realizing carbon neutrality for automobiles, but at present, EVs still faces a number of issues. The main issues include, for example, (1) cruising range, (2) installed battery capacity, (3) charging time, (4) infrastructure facilities, and (5) support for Heavy-duty commercial vehicles. Full electrification of heavy-duty trucks, in particular, requires high power output. This means that enormous installed battery capacity is necessary, and as a result, cruising range on a par with engine-driven vehicles cannot be readily achieved. Therefore a dynamic charge system was devised here that would provide electric power to EVs directly from the infrastructure so that EVs could undergo intermittent charging while driving. This is a conductive charging system that operates from the side of the vehicle (roadside), and research has been underway on the application of this approach to passenger cars and race cars.

The use of wireless power transfer systems, consisting of inductive electrical coils on the vehicle and the power source may be designed for dynamic operations where the vehicle will absorb energy at highway speeds from transmitting coils in the road. This has the potential to reduce the onboard energy storage requirements for vehicles while enabling significantly longer missions. This paper presents an approach to architecting a dynamic wireless power transfer corridor for heavy duty battery electric commercial freight vehicles. By considering the interplay of roadway power capacity, roadway and vehicle coil coverage, seasonal road traffic loading, freight vehicle class and weight, vehicle mobility energy requirements, on-board battery chemistry, non-electrified roadway vehicle range requirements, grid capacity, substation locations, and variations in electricity costs, we minimize the vehicle TCO by architecting the electrified roadway and the vehicle battery simultaneously.

Overcharging lithium-ion batteries is a failure mode that is observed if the battery management system (BMS) or battery charger fails to stop the charging process as intended. Overcharging can easily lead to thermal runaway in a battery. In this paper, nickel manganese cobalt (NMC) battery modules from the Chevrolet Bolt, lithium manganese oxide (LMO) battery modules from the Chevrolet Volt, and lithium iron phosphate (LFP) battery modules from a hybrid transit bus were overcharged. The battery abuse and emissions tests were designed to intentionally drive the three different battery chemistries into thermal runaway while measuring battery temperatures, battery voltages, gaseous emissions, and feedback from volatile organic compound (VOC) sensors. Overcharging a battery can cause lithium plating and other exothermic reactions that will lead to thermal runaway.

Electronic control units of Bendix® ABS/ESC and Collision Mitigation Systems have the capability to record event data in the ABS/ESC control unit. Bendix refers to this event data recording functionality as the Bendix Data Recorder (BDR). This paper presents an overview of the BDR functionality and examines the range and resolution of data elements, the synchronicity or timing of the recorded data, and application of the data for use in analyzing crashes. Various tests were performed using trucks equipped with Bendix® Wingman® Fusion™ and were conducted in a manner to trigger BDR records. BDR data was compared to data collected from the J1939 CAN Bus and from Racelogic VBOX data loggers.

There have been many studies regarding the stability of vehicles following a sudden air loss event in a tire. Previous works have included literature reviews, full-scale vehicle testing, and computer modeling analyses. Some works have validated physics-based computer vehicle simulation models for passenger vehicles and other works have validated models for heavy commercial vehicles. This work describes a study wherein a validated vehicle dynamics computer model has been applied to extrapolate results to higher event speeds that are consistent with travel speeds on contemporary North American highways. This work applies previously validated vehicle dynamics models to study the stability of a five-axle commercial tractor-semitrailer vehicle following a sudden air loss event for a steer axle tire. Further, the work endeavors to understand the analytical tire model for tires that experience a sudden air loss.

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.

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.

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 novel wave-shaped bowl piston geometry design with protrusions has been proved in previous studies to enhance late-cycle mixing and therefore significantly reduce soot emissions and increase engine thermodynamic efficiency. The wave-shaped piston is characterized by the introduction of evenly spaced protrusions around the inner wall of the bowl, with a matching number with the number of injection holes, i.e., flames. The interactions between adjacent flames strongly affect the in-cylinder flow and the wave shape is designed to guide the near-wall flow. The flow re-circulation produces a radial mixing zone (RMZ) that extends towards the center of the piston bowl, where unused air is available for oxidation promotion. The waves enhance the flow re-circulation and thus increase the mixing intensity of the RMZ.

Most heavy trucks should be fully electric, using a combination of batteries and catenary electrification, but heavy trucks requiring very long unsupported range will need chemical fuels. At the scale of heavy trucks, compressed hydrogen can match the specific energy of diesel, but its energy density is five times lower, limiting range to around 2,000 km. Scaling green hydrogen production and addressing leakage must be priorities. Hydrogen-derived electrofuels—or “e-fuels”—have the potential to scale, and while the economic comparison currently has unknowns, clean air considerations have gained new importance Decarbonized Power Options for Long-haul Commercial Vehicles discusses these energy sources as well as the caveats related to bioenergy usage, and reasons to prefer ethanol or methanol to diesel-type fuels. Click here to access the full SAE EDGETM Research Report portfolio.

In any off-highway machinery throughout the product development cycle, noise is considered an important characteristic. This characteristic drives the product quality, safety, and productivity and meets the homologation requirements. Identifying the critical noise source and finding out the true root cause of the noise source is a very critical element in improving the design to reduce the noise levels. A systematic approach is needed to understand the behavior of the system, which can be achieved through collaborative efforts among the analysis, design, and testing teams. This paper describes how virtual analysis helps to determine the main source of noise radiation in the audible frequency range of the human ear. The sound pressure level (SPL) in the test data at the end unit drive of an agriculture machine showed high peaks at a few frequencies in the critical frequency range. The spectral content remains the same regardless of the backshaft speed.

According to the International Energy Agency, of world energy consumption, fuel oil and natural coal, as primary sources of energy for some process, correspond to about 60% of the total. This consumption has been increasing for decades, mainly in the transport sector, including railways. In Brazil, in 2019, the transport sector represented 32.7% of energy consumption. At VLI Logística, a company that operates 7,000 km of railways in Brazil, consumption in 2020 was 203 million litres of diesel, which generated a cost of US$ 86 million. In this context, it is necessary to increase energy efficiency in the sector and, for this, the feasibility of recovering waste heat from the internal combustion engine (ICE) of a locomotive must be verified. The present study was carried out considering a GE 7FDL engine, 16 cylinders, turbocharged, with water cooling and 4,020 HP (2,998.92 kW) of power.