Browse Topic: Medium trucks
REE Automotive is aiming to be a major disruptor in the medium-duty truck space with the rollout of its P7 EV chassis. The P7 frame is built around its “REEcorners” suspension, which are modular suspension units featuring REE's x-by-wire design. By packaging components into the area between the chassis and the wheel, REE claims that it was able to design the P7 with a completely flat chassis with up to 35% more interior volume for passengers, cargo and batteries. “The REEcorners suspension system is the core of the technology that we built this truck around,” Peter Dow, VP of engineering for REE Automotive, said during an interview with Truck & Off-Highway Engineering. “It also allows us to achieve the level of vehicle dynamics we were looking for. We were trying to make a truck that was very exciting and easy to drive.”
Improvements in component/system design is a daily challenge these days, always looking for high performance, reduced mass and low costs. The source for the best fit between these factors, coupled with adequate durability performance, is crucial to the success of a given product and this is what motivates engineering teams around the world. The demand for efficient projects with short deadlines for validation and certification is huge and simulation tools focused on accelerated durability and virtual validation are increasingly being used. When developing a new spring for commercial vehicles, lessons learned from the actual loads applied to the suspension are the “key” to a successful project. The loads/stresses from the ground (vertical loads, lateral loads, longitudinal and braking loads) are quite high and, consequently, relevant to the proper definition of the design of the suspension components. The objective of this work is to describe the main development activities faced during
Several commercial truck OEMs revealed new medium-duty EVs at NTEA's 2023 Work Truck Week (WTW) in Indianapolis, Indiana. Interest in Class 5, 6 and 7 EVs has ramped up rapidly in recent years, and many OEMs are rolling out new models to meet the increased demand.
Allison Transmission continues to invest in and accelerate its electric-vehicle propulsion solutions, but it also remains committed to its conventional-product portfolio, which the company expects to remain relevant for decades. Boosting the capabilities of both technology pathways is Allison's next-generation electronic controls platform, which features advanced communications, functional safety, cybersecurity and over-the-air (OTA) programming capability. Allison partnered with multiple OEMs to build the first commercial vehicles equipped with the next-gen platform, which combines state-of-the-art microprocessor and software operating system technology. Freightliner Custom Chassis Corp. has begun producing the first walk-in vans equipped with the enhanced electronic controls. Other OEMs using the new system include Mack Trucks in its medium-duty trucks, Prevost and MAN. Allison expects all OEM partners to transition to this controls platform by February 2023.
The scope and purpose of this SAE Recommended Practice is to provide a classification system for deformation sustained by trucks involved in collisions on the highway. Application of the document is limited to medium trucks, heavy trucks, and articulated combinations.1 The Truck Deformation Classification (TDC) classifies collision contact deformation, as opposed to induced deformation, so that the deformation is segregated into rather narrow limits or categories. Studies of collision deformation can then be performed on one or many data banks with assurance that data under study are of essentially the same type.2 Many of the features of the SAE J224 MAR80 have been retained in this document, although the characters within specific columns vary. Each document must therefore be applied to the appropriate vehicle type. It is also important to note that the TDC does not identify specific vehicle configurations and body types. The TDC is an expression, useful to persons engaged in vehicle
SAE J1978/ISO 15031-4 specifies a complementary set of functions to be provided by an OBD-II scan tool. These functions provide complete, efficient, and safe access to all regulated OBD (on-board diagnostic) services on any vehicle which is compliant with SAE J1978/ISO 15031-4. The SAE J1978 content of this document is intended to satisfy the requirements of an OBD-II scan tool as required by current U.S. on-board diagnostic (OBD) regulations. The ISO 15031-4 content of this document is intended to satisfy the requirements of OBD requirements in countries other than the U.S., and includes functionality not required or not allowed in the U.S. This document specifies: A means of establishing communications between an OBD-equipped vehicle and an OBD-II scan tool. A set of diagnostic services to be provided by an OBD-II scan tool in order to exercise the services defined in SAE J1979/ISO 15031-5. SAE J1978/ISO 15031-4 does not preclude the inclusion of additional capabilities or functions
The noise and vibration are directly related to the perceived quality of a vehicle and it is crucial that the manufacturers focus their efforts to reduce that. When an unusual noise appears, it is a great challenge to define an approach for understanding the phenomenon, identifying the cause and then defining a solution to reduce its effect. A “knocking noise” coming from the brake rigid pipes is perceived while driving the vehicle in a cobbled pavement at low speed and it coincides with the closure of brake system module inlet valves. When a valve closes quickly, there is a sudden change in the flow velocity, which generates a pressure transient in the brake fluid inducing vibrations in the rigid pipes. The pressure transient can be minimized by reducing the speed at which the pressure waves travel in the pipe. The bulk modulus, the density of the fluid, the velocity of valve closing, the Young’s modulus and the dimensions of the pipes, determine the wave speed. The objective of this
In this study, the preliminary validation method of the steering system is constructed and the objective is to satisfy the target performance in the conceptual design stage for minimizing the problems after the detailed design. The first consideration about steering system is how to extract the reliable steering effort for parking. The tire model commonly used in MBD(Multi-Body Dynamics) has limited ability to represent deformations under heavy loads. Therefore, it is necessary to study adequate tire model to simulate the behavior due to the large deformation and friction between the ground and the tire. The two approaches related with F tire model and mathematical model are used. The second is how to extract each link’s load in the conceptual design stage. Until now, each link’s load could be derived only by actual vehicle test, and a durability analysis was performed using only pre-settled RIG test conditions. Therefore, in this study, we established the process of deriving the RIG
This paper provides a summary of a Liquefied Petroleum Gas (LPG) concept engine developed for medium duty applications (class 6-7 trucks) targeting high efficiency with a power density that matches turbocharged diesel engines. The turbocharged in-line 6 cylinder engine incorporates an advanced spark ignition combustion system design, a purpose built medium-duty class engine structure optimized for operation with a direct propane injection system, dual overhead cams with individual cam phasers and twin-entry turbocharger. The high tumble charge motion combustion system targeted for operation with direct injected (DI) LPG has resulted in an engine capable of producing up to 22 bar brake mean effective pressure (BMEP) at high brake thermal efficiency (BTE) throughout the operating map. The high BTE combined with low carbon to hydrogen ratio of LPG results in 12% lower Brake Specific CO2 (BSCO2) emissions on the heavy-duty FTP cycle when compared to a diesel engine of same displacement and
This document establishes minimum performance criteria at GCWR and calculation methodology to determine tow-vehicle TWR for passenger cars, multipurpose passenger vehicles, and trucks. This includes all vehicles up to 14000 pounds GVWR.
This SAE Recommended Practice applies to all trucks that are equipped with armlift bodies, carrier bodies, wheel lift bodies, wrecker, and underlift bodies. Additional rating methods are provided for tow slings, truck hitches, and chain assemblies.
Recent research to investigate the aerodynamic-drag reduction associated with truck platooning systems has begun to reveal that surrounding traffic has a measurable impact on the aerodynamic performance of heavy trucks. A 1/15-scale wind-tunnel study was undertaken to measure changes to the aerodynamic drag experienced by heavy trucks in the presence of upstream traffic. The results, which are based on traffic conditions with up to 5 surrounding vehicles in a 2-lane configuration and consisting of 3 vehicle shapes (compact sedans, SUVs, and a medium-duty truck), show drag reductions of 1% to 16% for the heavy truck model, with the largest reductions of the same order as those experienced in a truck-platooning scenario. The data also reveal that the performance of drag-reduction technologies applied to the heavy-truck model (trailer side-skirts and a boat-tail) demonstrate different performance when applied to an isolated vehicle than to conditions with surrounding traffic. The results
The development, analysis, and comparison of battery electric class-4 medium-duty trucks equipped with three possible powertrain layouts, namely, direct drive, single-speed gearbox, and two-speed transmission options, are discussed in this paper. The problem definition is included and the performance evaluation criteria for the proposed truck architectures are defined, namely, acceleration time, top speed, and efficiency. Designs of four new traction motors are proposed and their benefits compared for use in medium-duty electric trucks (e-trucks). The procedure for gear-ratio range selection is outlined, the ranges of gear ratios for the single-speed gearbox and two-speed transmission powertrains being calculated for each of the proposed electric traction motors. The simulation and gear-ratio optimization tasks for the e-trucks are formulated. The energy consumption of the e-truck with the three possible powertrain combinations is minimized over the six driving cycles. The most
This SAE Recommended Practice is applicable to all E/E systems on MD and HD vehicles. The terms defined are largely focused on compression-ignited and spark-ignited engines. Specific applications of this document include diagnostic, service and repair manuals, bulletins and updates, training manuals, repair data bases, under-hood emission labels, and emission certification applications. This document focuses on diagnostic terms, definitions, abbreviations, and acronyms applicable to E/E systems. It also covers mechanical systems which require definition. Nothing in this document should be construed as prohibiting the introduction of a term, abbreviation, or acronym not covered by this document. The use and appropriate updating of this document is strongly encouraged. Certain terms have already been in common use and are readily understood by manufacturers and technicians, but do not follow the methodology of this document. These terms fall into three categories: a Acronyms that do not
Higher compression ratio and turbocharging, with engine downsizing can enable significant gains in fuel economy but require engine operating conditions that cause engine knock under high load. Engine knock can be avoided by supplying higher-octane fuel under such high load conditions. This study builds on previous MIT papers investigating Octane-On-Demand (OOD) to enable a higher efficiency, higher-boost higher compression-ratio engine. The high-octane fuel for OOD can be obtained through On-Board-Separation (OBS) of alcohol blended gasoline. Fuel from the primary fuel tank filled with commercially available gasoline that contains 10% by volume ethanol (E10) is separated by an organic membrane pervaporation process that produces a 30 to 90% ethanol fuel blend for use when high octane is needed. In addition to previous work, this paper combines modeling of the OBS system with passenger car and medium-duty truck fuel consumption and octane requirements for various driving cycles. Medium
In this paper an alternative engineering solution to control vehicle steering wheel vibration is presented. The strategy is focused on the implementation of an effective tuned vibration absorber which also complies with time frame and costs requisites. The vibration levels in this case study are enhanced due resonances in the chassis frame and steering column. The tuned mass damper is basically a suspended mass attached on a vulcanized rubber body, aiming for the customer benefits; this solution can be classified as low cost as well low complexity for implementation. In this case study, a mid-size truck was used as a physical hardware and the data were collected through accelerometers on the steering wheel and other critical components. As a control factor, different tunings on different parts were applied to optimize the auxiliary system performance and robustness. As a final output, the relationship between the tuned mass damper and the acceleration levels on the steering wheel is
This SAE Recommended Practice applies to fasteners/fixing nuts as specified in SAE J694 and SAE J1835 used for disc wheels and demountable rim attachment respectively. Only the test methods necessary to ensure proper wheel or rim assembly are specified. Fasteners for less common and special applications are not included.
The scope and purpose of this SAE Recommended Practice is to provide a classification system for deformation sustained by trucks involved in collisions on the highway. Application of the document is limited to medium trucks, heavy trucks, and articulated combinations.1 The TDC classifies collision contact deformation, as opposed to induced deformation, so that the deformation is segregated into rather narrow limits or categories. Studies of collision deformation can then be performed on one or many data banks with assurance that data under study are of essentially the same type.2 Many of the features of the SAE J224 MAR80 have been retained in this document, although the characters within specific columns vary. Each document must therefore be applied to the appropriate vehicle type. It is also important to note that the Truck Deformation Classification (TDC) does not identify specific vehicle configurations and body types. The TDC is an expression, useful to persons engaged in vehicle
The government of India has decided to implement Bharat Stage VI (BS-VI) emissions standards from April 2020. This requires OEMs to equip their diesel engines with costly after-treatment, EGR systems and higher rail pressure fuel systems. By one estimate, BS-VI engines are expected to be 15 to 20% more expensive than BS-IV engines, while also suffering with 2 to 3 % lower fuel economy. OEMs are looking for solutions to meet the BS-VI emissions standards while still keeping the upfront and operating costs low enough for their products to attract customers; however traditional engine technologies seem to have exhausted the possibilities. Fuel economy improvement technologies applied to traditional 4-stroke engines bring small benefits with large cost penalties. One promising solution to meet both current, and future, emissions standards with much improved fuel economy at lower cost is the Opposed Piston (OP) engine. Recently, there has been surge in developing highly efficient OP engine
This study aimed to clarify the relationship between truck-pedestrian crash impact velocity and the risks of serious injury and fatality to pedestrians. We used micro and macro truck-pedestrian accident data from the Japanese Institute for Traffic Accident Research and Data Analysis (ITARDA) database. We classified vehicle type into five categories: heavy-duty trucks (gross vehicle weight [GVW] ≥11 × 103 kg [11 tons (t)], medium-duty trucks (5 × 103 kg [5 t] ≤ GVW < 11 × 103 kg [11 t]), light-duty trucks (GVW <5 × 103 kg [5 t]), box vans, and sedans. The fatality risk was ≤5% for light-duty trucks, box vans, and sedans at impact velocities ≤ 30 km/h and for medium-duty trucks at impact velocities ≤20 km/h. The fatality risk was ≤10% for heavy-duty trucks at impact velocities ≤10 km/h. Thus, fatality risk appears strongly associated with vehicle class. The results also revealed that a 10 km/h reduction in impact velocities could mitigate the severity of pedestrian injuries at impact
In this paper, researchers at the National Renewable Energy Laboratory present the results of simulation studies to evaluate potential fuel savings as a result of improvements to vehicle rolling resistance, coefficient of drag, and vehicle weight as well as hybridization for four powertrains for medium-duty parcel delivery vehicles. The vehicles will be modeled and simulated over 1,290 real-world driving trips to determine the fuel savings potential based on improvements to each technology and to identify best use cases for each platform. The results of impacts of new technologies on fuel saving will be presented, and the most favorable driving routes on which to adopt them will be explored.
Various 1D simulation tools (KULI & LMS Amesim) and 3D simulation tools (ANSYS FLUENT®) can be used to size and evaluate truck cooling system design. In this paper, ANSYS FLUENT is used to analyze and validate the design of medium duty truck cooling systems. LMS Amesim is used to verify the quality of heat exchanger input data. This paper discusses design and simulation of parent and derivative trucks. As a first step, the parent truck was modeled in FLUENT (using standard' k - ε model) with detailed fan and underhood geometry. The fan is modeled using Multiple Reference Frame (MRF) method. Detailed geometry of heat exchangers is skipped. The heat exchangers are represented by regular shape cell zones with porous medium and dual cell heat exchanger models to account for their contributions to the entire system in both flow and temperature distribution. Good agreement is observed between numerical and experimental engine out temperatures at different engine operating conditions. Once
This document supersedes SAE J1962 200204, and is technically equivalent to ISO/DIS 15031-3: December 14, 2001. This document is intended to satisfy the requirements of an OBD connector as required by U.S. On-Board Diagnostic (OBD) regulations. The diagnostic connection specified in this document consists of two mating connectors, the vehicle connector and the external test equipment connector. This document specifies: a The functional requirements for the vehicle connector. These functional requirements are separated into four principal areas: connector location/access, connector design, connector contact allocation, and electrical requirements for connector and related electrical circuits, b The functional requirements for the external test equipment connector. These functional requirements are separated into three principal areas: connector design, connector contact allocation, and electrical requirements for connector and related electrical circuits.
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