Browse Topic: Heavy trucks

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Steering Control Systems - Heavy TrucksJ2425_202111 (Current)11/9/2021
This SAE Recommended Practice describes a laboratory test procedure and requirements for evaluating the characteristics of heavy-truck steering control systems under simulated driver impact conditions, as well as driver entry/egress conditions. The test procedure employs a torso-shaped body block that is impacted against the steering wheel.
Truck Crashworthiness Committee
Driveline Parking Brake Test Procedure for Medium Duty VehiclesJ2690_202110 (Current)10/28/2021
This SAE Recommended Practice establishes uniform test procedures for friction based parking brake components used in conjunction with hydraulic service braked vehicles with a gross vehicle weight rating greater than 4500 kg (10 000 lb). The components covered in this document are the primary actuation and the foundation park brake. Various peripheral devices such as application dashboard switches or indicators are not included. These test procedures include the following: a Brake Related Tests 1 Brake Functional Performance 2 Brake Dynamic Torque Performance 3 Brake Corrosion Resistance 4 Brake Endurance with Torque 5 Brake Endurance without Torque 6 Vibration Resistance 7 Brake Ultimate Static Load 8 Brake Lining Wear Adjuster Function b Actuation Related Tests 1 Mechanical Actuator Functional Performance 2 Mechanical Actuator Endurance 3 Mechanical Actuator Quick Release 4 Mechanical Actuator Ultimate Load 5 Spring Apply Actuator Functional Performance 6 Spring Apply Actuator Operating Temperature Range 7 Spring Apply Actuator Endurance 8 Spring Apply Actuator Corrosion Resistance 9 Spring Apply Actuator On-Off Switch 10 Spring Apply Actuator Vibration
Truck and Bus Hydraulic Brake Committee
Occupant Restraint System Evaluation - Lateral Rollover System-Level Heavy TrucksJ2426_202103 (Current)3/1/2021
This SAE Recommended Practice describes the test procedures for conducting simulated dynamic lateral rollover restraint system tests for heavy truck applications. Its purpose is to establish recommended test procedures that will standardize restraint system testing for heavy trucks. Descriptions of the test set-up, test instrumentation, photographic/video coverage, and the test fixtures are included.
Truck Crashworthiness Committee
Cab Sleeper Occupant Restraint System TestJ1948_202101 (Current)1/27/2021
This SAE Recommended Practice provides a standardized test procedure for heavy-duty truck sleeper berth restraints to determine whether they meet the FMCSR 393.76(h) requirements.
Truck Crashworthiness Committee
Single Conductor Cable for Heavy-Duty Applications - Truck and BusJ2549_202012 (Current)12/4/2020
This SAE Standard establishes the minimum construction and performance requirements for single conductor cable for use on trucks, trailers, and converter dollies.
Truck and Bus Electrical Systems Committee
Inverter Requirements for Class Eight Trucks - Truck and BusJ2697_202011 (Current)11/18/2020
This SAE Recommended Practice is intended to describe the application of single-phase DC to AC inverters, and bidirectional inverter/chargers, which supply power to ac loads in Class heavy duty on-highway trucks (10K GVW). The document identifies appropriate operating performance requirements and adds some insight into inverter selection. This document applies to factory and after-market installed DC-to-AC inverter systems (Including inverter chargers) providing up 3000 W of 120 VAC line-voltage power as a convenience for operator and passenger use. Such inverters are intended to power user loads not essential to vehicle Operation or safety (e.g., HVAC, TV, microwave ovens, battery chargers for mobile phones or laptop computers, audio equipment, etc.). Systems incorporate the inverter itself as well as the input, output, control, and signal wiring associated with the inverter. Requirements are given for the performance, safety, reliability, and environmental compatibility of the system. These are recommended requirements to be used by vehicle manufacturers in the development of their own specifications, which may incorporate more or less stringent requirements. This document scope excludes military vehicles, bus and 28 V systems.
Truck and Bus Electrical Systems Committee
Occupant Restraint Dynamic System Evaluation - Frontal Impact Heavy TrucksJ2418_202011 (Current)11/9/2020
This SAE Recommended Practice describes the test procedures for conducting frontal impact restraint tests for heavy truck applications. Its purpose is to establish recommended test procedures that will standardize restraint system testing for heavy trucks. Descriptions of the test set-up, test instrumentation, photographic/video coverage, and the test fixtures are included.
Truck Crashworthiness Committee
Comparative Analysis of Emergency Evasive Steering for Long Combination Vehicles02-13-03-001810/10/2020
This study provides a simulation-based comparative analysis of the distance and time needed for long combination vehicles (LCVs) - namely, A-doubles with 28-, 33-, and 48-ft trailers - to safely exercise an emergency, evasive steering maneuver such as required for obstacle avoidance. The results are also compared with conventional tractor-semitrailers with a single 53-ft trailer. A multi-body dynamic model for each vehicle combination is developed in TruckSim® with an attempt to assess the last point to steer (LPTS) and evasive time (ET) at various highway speeds under both dry and wet road conditions. The results indicate that the minimum avoidance distance and time required for the 28-ft doubles vary from 206 ft (60 mph) to 312 ft (80 mph) and 2.3 s to 2.6 s, respectively. The required LPTS represents a 6% to 31% increase when compared with 53-ft semitrucks. When driving below 76 mph on a dry road and below 75 mph on a wet road, the 28-ft doubles exhibit LPTS and ET that are larger than 33-ft doubles. In addition, the 33-ft doubles exhibit larger LPTS and ET than 48-ft doubles for the highway speeds considered. This is mainly attributed to the longer trailer wheelbase that causes smaller rear trailer amplifications. At speeds higher than 76 mph on dry roads and 75 mph on wet roads, however, an opposite trend is observed. As the trailer length increases, the distance and time needed to safely avoid an obstacle also increase. A comparison between dry and wet road conditions is also conducted, with the results indicating that more time and distance would be needed for obstacle avoidance on wet roads.
Chen, Yang, Zhang, Zichen, Ahmadian, Mehdi
Designing Next Generation Exhaust Aftertreatment Systems Using Machine Learning02-13-03-00169/25/2020
With ever tightening emission standards, the automotive industry is continuously seeking novel ways to improve the aftertreatment system (ATS). Exhaust treatment systems using diesel emission fluid (DEF), in conjunction with selective catalytic reduction (SCR) and diesel oxidation converters (DOC), have been gaining popularity in the heavy equipment industry. Spraying DEF (mixture of urea and water) into the exhaust flow can convert harmful NOx gases into N2 and H2O. Design of ATSs focuses on high evaporation rate and uniform mixing of ammonia at the entrance to the SCR catalyst. This study applied support vector regressor (SVR), a machine learning (ML) method to a database of computational fluid dynamics (CFD) simulations to develop a highly efficient mixer with high heat exchange characteristics. Over 500 mixer designs were evaluated using CFD and were then used to train the SVR model. The trained ML model was then used as a surrogate to the CFD and coupled with the genetic algorithm (GA), an optimization technique, to further refine the design parameters. The optimal design obtained from this methodology showed a remarkable performance improvement compared to the baseline.
Singh, Samrendra K., Braginsky, Daniel, Tamamidis, Panos, Gennaro, Monacelli
Modeling and Analysis of a Heavy Vehicle with Self-Steering Axle02-13-01-00034/21/2020
Commercial vehicles often incorporate self-steering axles to meet the axle load requirements while providing improved maneuverability, reduced off-tracking, and reduced tire and pavement wear. Market forces promote the design of more efficient self-steering axle products with reduced weight and more features. Manufacturers also work to differentiate their products through unique designs and new concepts. Traditional design methods for self-steering axles include empirical and trial-and-error methods to set the steering mechanism design parameters based on known design baselines and prior experience. For innovative new concepts that are too far from the traditional designs, it is desirable to have alternative ways for evaluating the expected performance. This article introduces a reduced-order model that allows the rapid analysis of the steering dynamic behavior of self-steering axles. The model combines a pendulum-like lateral stiffness model with the axle steering dynamics which are then coupled to suitable reduced-order models for tractor-trailer combinations on which the self-steering axle can be mounted. The proposed model is shown to capture the shimmy behavior of the self-steering axle using phase portraits of the coupled nonlinear system. The model provides a way to identify the important stiffness and damping parameters of steering axle design concepts that are not yet sufficiently developed, and therefore the details required for full multi-body dynamic analysis are not available.
Delorenzis, Damon, Ayalew, Beshah
A New Simulation Approach of Estimating the Real-World Vehicle Performance2020-01-03704/14/2020
Due to the variability of real traffic conditions for vehicle testing, real-world vehicle performance estimation using simulation method become vital. Especially for heavy duty vehicles (e.g. 40 t trucks), which are used for international freight transport, real-world tests are difficult, complex and expensive. Vehicle simulations use mathematical methods or commercial software, which take given driving cycles as inputs. However, the road situations in real driving are different from the driving cycles, whose speed profiles are obtained under specific conditions. In this paper, a real-world vehicle performance estimation method using simulation was proposed, also it took traffic and real road situations into consideration, which made it possible to investigate the performance of vehicles operating on any roads and traffic conditions. The proposed approach is applicable to all kind of road vehicles, e.g. trucks, buses, etc. In the method, the real-road network includes road elevation. The traffic conditions and vehicles parameters were the inputs for traffic simulation. Based on the outputs (speed profiles and elevations) of target vehicles in the traffic simulation, then the real-world performance of the vehicle was achieved by vehicle simulation under the given traffic conditions. The fuel consumption of the vehicle calculated using this method was 34.00 L/100 km under free traffic flow conditions over highway route.
Gao, Jianbing, Chen, Haibo, Chen, Junyan, Dave, Kaushali
Simulation of Aftertreatment Thermal Management Strategies for Low-Load Operation2020-01-03594/14/2020
The low-NOx regulation for heavy duty trucks proposed by California’s Air Resources Board (CARB) will present a significant challenge to truck, engine and aftertreatment system manufacturers. This regulation will include a new test cycle representative of low-load operation. With low-load cycles, NOx conversion by the SCR (selective catalytic reduction) system is limited primarily by the exhaust temperature; thus, thermal management will dominate development. Simulation can be used to examine different thermal management strategies, and to define high-level requirements for new components. In this study, modeling was used to investigate SCR performance on two different low-load cycles, including the one selected by CARB for the low-NOx regulation. First, the “thermal deficit” of the cycle was quantified using a constant heat input. Next, direct heating of the exhaust with a fuel mini-burner or an electric heater, using realistic controls, was simulated to determine their capability to overcome the thermal deficit. For comparison, the performance of a dual-injection SCR system on these cycles was also modeled.
Harris, Thomas
Requirements for Built-in Service Port for On-Board DiagnosticsJ2744_202003 (Current)3/11/2020
This document presents the requirements for a built-in service port to be used in vehicles intended to comply with Enhanced Evaporative Emissions Requirements. The primary function of the Service Port (Valve Assembly-Evaporative Emission Canister Purge Harness Service) is to provide non-destructive access to the evaporative emissions system to enable testing of the integrity of the system. The Service Port is used to introduce air pressure or fuel vapors into, or evacuates them out of, the system. This access may be used for the following evaluations: • Evaporative System Certifications Canister Loading and Purging • End-of-line Testing System Integrity • Service (e.g. OBD MIL on) Leak Location and Repair Verification • In-Use Compliance Testing Canister Loading and Purging • Inspection/Maintenance Testing System Integrity and Purge Check
Fuel Systems Standards Committee
Control Performance of Damping and Air Spring of Heavy Truck Air Suspension System with Optimal Fuzzy Control10-04-02-00132/28/2020
The air suspension system of heavy trucks not only improves the vehicle’s ride comfort but also reduces the negative impact on the road surface. In order to evaluate the performance of the control damping (CD) and the control air spring (CAS) of the vehicle air suspension system on the ride comfort and the road friendliness, a three-dimensional (3D) nonlinear dynamic model with 14 degrees of freedom (DOF) of the heavy trucks and optimal fuzzy control (OFC) with control rules optimized by the genetic algorithm (GA) are proposed in this study. The root mean square (RMS) acceleration response of the tractor and the dynamic load coefficient (DLC) at the wheel axles are chosen as objective functions under the various operating conditions. Contrastive analysis of the RMS and DLC values with the passive (P), CD, and CAS methods of the air suspension system is carried out respectively. The research result shows that both the CD and CAS methods remarkably improve the ride comfort and road friendliness of the heavy trucks in comparison with P, especially the CAS method has an obvious effect on mitigating the road damage in comparison with the CD method; conversely the CD method is better than the CAS method to improve the tractor’s ride comfort under different operating conditions.
Nguyen, Vanliem, Jiao, Renqiang, Zhang, Jianrun
Primary and Auxiliary Seven Conductor Electrical Connector for Truck-Trailer Jumper CableJ560_202002 (Current)2/25/2020
This SAE Standard provides the minimum requirements for primary and auxiliary jumper cable plug and receptacle for the truck-trailer and converter dolly jumper cable systems for 12 VDC nominal applications. It includes the test procedures, design, and performance requirements.
Truck and Bus Electrical Systems Committee
Self-driving trucks cut fuel consumption by 10%20TOFHP02_122/1/2020
Enhancing safety and helping combat driver shortages are two benefits that heavy-duty autonomous-truck proponents have preached during development. You can now add significant fuel savings to the list. Results of a new study from the University of California San Diego's Jacobs School of Engineering and TuSimple show that the San Diego-based company's autonomous technology reduces fuel consumption of heavy-duty trucks by at least 10%.
Gehm, Ryan
Development challenges of hydraulic brakes for commercial vehicles2019-36-00131/13/2020
The automotive research and development environment is increasingly challenging and complex, full of new technologies, regulations and customized customer needs. In addition, the cargo transportation market is very dynamic and competitive, becoming complex the strategies for companies in this segment. According to Anfavea (2018), this trend, especially in large urban centers, has driven the intention to use light commercial vehicles to capillize deliveries in destinations with a high demographic concentration and traffic limited to medium and heavy vehicles. In this scenario, the demand for diversified products is increasing in order to overcome the main tradeoff: “minimizing the size of the trucks and maximize the load capacity”. It brings the number of complex projects. The brake system is greatly impacted in these developments mainly because light commercial vehicles are situated in a weight range that we can call "identity crisis" if on the one hand they need an upgrade compared to a conventional car and use the hydraulic brake on the other one need a downgrade of a medium or heavy truck that brings robustness and pneumatic brakes. The definition of the type of assistance is a determining factor, hydraulic brake; pneumatic brake or a hybrid brake (air over hydraulic). Each type has its advantages and disadvantages, which are directly related to the vehicle's application such as installation package, serviceability, service brake costs and performance and especially parking brake. This work shows the study and development of the brake system including the detailed presentation of a dry caliper, implemented as disruptive innovation technology. It also has a new concept applied to a commercial vehicle, developed in Brasil and used as footprint own knowledge for the specific needs of the market and provides a very cost-benefit commitment for the customer, yet brings the wished confidence of the parking brake function for drivers.
Vetter, Narã Vieira, Carlos de Oliveira, Antonio, Fontes, Eduardo Henrique Souza, Nogueira, Felipe, Fonseca, Guilherme Henrique, Nuss de Souza, Luis Fernando, Oliveira dos Reis, Rodrigo de, Manenti, Vangelo Cardoso
Power System for Hybrid Heavy-Duty TrucksTBMG-358041/1/2020
Heavy-duty trucks such as 18-wheelers are virtually all powered by diesel engines. They account for a significant portion of worldwide greenhouse gas emissions but little has been done to curb their climate-change-inducing exhaust.
The performance and mechanisms of organic polymeric friction modifiers in low viscosity engine oils2019-01-220412/19/2019
The requirement of OEMs to reduce CO2 emissions is leading to a reduction in viscosity of engine oils with 0W20 approved oils now common. 0W 16 approvals are growing in popularity and will be further supported in the US by the introduction of ILSAC GF-6B. Japanese OEMs are driving the development of 0W- 12 and 0W08 grades which will be supported by JASO GLV-1. These low viscosity engine oils can contain MoDTC with very high levels of 1000+ppm molybdenum to achieve the fuel economy improvement required to pass engine tests such as Sequence VIE. Molybdenum usage at this level contributes to sulphated ash increase. It can also have a negative impact on deposits. This paper examines the performance and mechanism of two ashless polymeric friction modifiers in a 0W20 formulation. These polymeric friction modifiers have been shown to give fuel economy benefits in Sequence VIE engine tests. The aim of this work is to better understand the influence and interaction of these polymeric friction modifiers in the presence of ZDDP as well as other additives, in tribological testing. Specifically, how the friction and wear benefits observed in MTM testing correlate to the chemical composition of the tribofilm as characterised by X-ray Photoelectron Spectroscopy (XPS) and Raman spectroscopy. Further work detailing the combination of polymeric friction modifier and MoDTC was conducted on the MTM, including surface characterisation for potential synergistic properties in the reference oil. Evidence of the polymeric friction modifier on the surface, and throughout the depth of the tribofilm, was observed, even in the presence of molybdenum containing additives. This work proves the good surface affinity and film forming properties of polymeric friction modifiers and highlights the differences in the tribofilm composition depending on the friction modifier(s) used.
Moody, Gareth, Eastwood, John, Ueno, Keiko
EDITORIAL: Hop on the hydrogen highway19TOFHP12_0612/1/2019
Two years ago at the inaugural North American Commercial Vehicle (NACV) Show in Atlanta, a recurring theme from nearly every truck manufacturer and supplier press conference was vehicle uptime, along with the various telematics and connectivity solutions that enable fleet managers to keep their trucks on the road. While these certainly were important topics at this year's NACV Show, the dominant takeaway from the Georgia World Congress Center was that alternative propulsion is top of mind for many industry players. Navistar launched a new business unit, NEXT eMobility Solutions, to deliver customized electrification solutions in the truck and school bus markets. The business unit, which will be based in the Detroit area, took little time to make a splash, revealing a prototype electric version of the International MV Series medium-duty vehicle, the eMV. The concept is powered by an electric motor with 474 kW peak power and 300 kW continuous power and is designed to accommodate battery-capacity options ranging from 107 to 321 kWh. Navistar says customers operating a truck with a 321-kWh battery in typical pickup-and-delivery cycles should expect a range of 250 miles (400 km) on a single charge.
Gehm, Ryan
Countering the Destabilizing Effects of Shifted Loads through Pneumatic Suspension Design10-04-01-000111/8/2019
This article proposes a novel approach to reduce the destabilizing impacts of the shifted loads of heavy trucks (due to improper loading or liquid slosh) by pneumatic suspension design. In this regard, the pneumatically balanced suspension with dual leveling valves is introduced, and its potential for the improvement of the body imbalance due to the shifted load is determined. The analysis is based on a multi-domain model that couples the suspension fluid dynamics, shifted-load impacts, and tractor-semitrailer dynamics. Truck dynamics is simulated using TruckSim, which is integrated with the pneumatic suspension model developed in AMESim. This yields a reasonable prediction of the effect of the suspension airflow dynamics on vehicle dynamics. Moreover, the ability of the pneumatic suspension to counteract the effects of two general shifted loads - static (rigid cargo) and dynamic (liquid) - is studied. The simulation results indicate that the dual-leveling-valve suspension results in a reduction in roll angle and roll rate of the vehicle body for both static and dynamic load-shifting cases, as compared to the conventional single-leveling-valve suspension. Suppression of the liquid sloshing behavior is obtained by the truck with the dual-leveling-valve suspension. Furthermore, the co-simulation platform established in the study is useful for efficient and accurate analyses of the coupled shifted load-pneumatic suspension-vehicle system dynamics.
Chen, Yang, Ahmadian, Mehdi
Braking Control Strategy Based on Electronically Controlled Braking System and Intelligent Network Technology2019-01-503811/4/2019
In order to solve the coupling problems between braking safety, economical efficiency of braking and the comfort of drivers, a braking control strategy based on Electronically Controlled Braking System (EBS) and intelligent network technology under non-emergency braking conditions is proposed. The controller utilizes the intelligent network technology’s characteristics of the workshop communication to obtain the driving environment information of the current vehicle firstly, and then calculate the optimal braking deceleration of the vehicle based on optimal control method. The strategy will distribute the braking force according to the ideal braking force distribution condition based on the EBS according to the braking deceleration; the braking force will be converted to braking pressure according to brake characteristics. Computer co-simulations of the proposed strategy are performed, the strategy is verified under different initial speeds. The results show that the strategy enables the vehicle to stop within a safe distance, keeps the brake deceleration as smooth as possible for better braking comfort while at the same time obtaining better braking economy by increasing braking efficiency under different initial speeds.
Zheng, Hongyu, Li, Rui
Knapheide saves costs, time by moving vehicle life testing in-house19TOFHP10_0810/1/2019
The Knapheide Manufacturing Co. has always sent its products out to be tested, but with the wide variety of product types that the Quincy, Ill.-based company makes, the cost of farming out the testing process had become excessive. The manufacturer specializes in the North American utility truck body market, both military and civilian grade, including crane trucks, electrician trucks, and Class 8 heavy-duty truck chassis. “Just one test could cost tens of thousands of dollars,” said Kent Birt, Knapheide testing project manager. In addition, the lead times associated with working through outside testing labs were long. “Often we had to wait six weeks or more for results, impacting our ability to meet schedules,” he added. Company managers concluded that they could save a lot of cost and improve customer service by developing their own test systems in-house.
Palmer, Jason
Q&A19TOFHP10_1310/1/2019
CNH Industrial is separating its On-Highway (commercial vehicles and powertrain) and Off-Highway (agriculture, construction and specialty vehicles) segments into two listed entities, as part of its new five-year 2020-2024 business plan, “Transform 2 Win.” CEO Hubertus M. Mühlhäuser and other CNH executive leaders made the announcement Sept. 3 at its Capital Markets Day event at the New York Stock Exchange (NYSE). The spin-off of its On-Highway assets-Iveco, Iveco Bus and Heuliez Bus commercial-vehicle brands and the FPT Industrial powertrain business-is expected to be completed in early 2021. According to Mühlhäuser, the move results from an extensive portfolio review that revealed the two businesses have diverging regulatory and customer requirements and are impacted differently by four accelerating industry megatrends: digitalization, automation, alternative propulsion and servitization.
Gehm, Ryan
Divergence of Thickness Loss vs. Weight Loss, Friction and Wear Behavior of Heavy Truck Brake Blocks: Development of a New Test Procedure for the Chase Tester2019-01-21079/15/2019
Heavy truck brake blocks are found to swell (or expand) permanently during testing or usage, especially so at high temperatures, thus leading to longer durability as measured by thickness loss, similar to light vehicle disc pads. This swelling phenomenon occurs continuously in the layer adjacent to the friction surface during testing or usage; not a one time event. The thickness loss estimated from the weight loss is always greater than measured thickness loss. Brake block wear does not increase linearly with increasing normal load, and the load-sensitivity of block wear is very much dependent on the products. A new test procedure has been developed for generating friction-vs.-temperature and wear-vs.-temperature data at a constant temperature employing intermittent braking on the Chase Brake Lining Quality Tester (SAE J661) and friction material wear can be compared on equivalent-work basis.
Rathee, Aman, Sharma, Devendra Kumar, Singh, Shivraj, Rhee, Seong Kwan
A Mild Hybrid SIDI Turbo Passenger Car Engine with Organic Rankine Cycle Waste Heat Recovery2019-24-01949/9/2019
While striving for more fuel-efficient vehicles, all possible measures are considered to increase the efficiency of the combustion engine powertrain. 48V mild hybrid technology is one such measure, SIDI (Spark Ignited Direct Injection) engines with Miller technology are another, while recovering energy from the engine’s waste heat (WHR) is yet another option. In this paper, results will be published from an advanced engineering project at Volvo Cars including all of these components. An ethanol based Organic Rankine Cycle (ORC) WHR-system was successfully built around a 4-cylinder, 2.0 litre SIDI-engine, including 48V mild hybrid technology, with vehicle packaging considered. A dedicated control system was also developed for the ORC system including communication between it and the engine. The ORC system uses the engine exhaust as the heat source, for which a purpose-built evaporator was designed and built to fit in the vehicle tunnel. The expansion of the ethanol vapour occurs in an axial piston expander coupled both electrically to the hybrid system and mechanically to the engine crankshaft via a belt-drive. This dual power output from the expander was found to be of particular importance for a passenger car with a transient driving style, giving the opportunity to recover more waste heat energy by overcoming the slow response from the steam system with the fast response of the electrical hybrid system. Initial results on the engine bench indicate, at high engine loads, a decrease in brake specific fuel consumption of 5-7% with stoichiometric engine operation. These results are in-line with our simulations also show that the combined powertrain system gives advantages in both city (mild hybrid), rural (optimized engine, WHR) and highway conditions (WHR).
Ekström, Fredrik B., Rolandson, Ola, Eriksson, Soren, Odenmarck, Christer, Svensson, Mattias, Eriksson, Andreas, Olsen, Hans
Empirical Investigation on the Effects of Rolling Resistance and Weight on Fuel Economy of Medium-Duty Trucks02-12-03-00168/28/2019
Abstract Vehicle rolling resistance and weight are two of the factors that affect fuel economy. The vehicle tire rolling resistance has a more significant influence than aerodynamics drags on fuel economy at lower vehicle speeds, particularly true for medium- and heavy-duty trucks. Less vehicle weight reduces inertia loads, uphill grade resistance, and rolling resistance. The influence of weight on the fuel economy can be considerable particularly in light- to medium-duty truck classes because the weight makes up a larger portion of gross vehicle weight. This article presents an empirical investigation and a numerical analysis of the influences of rolling resistance and weight on the fuel economy of medium-duty trucks. The experimental tests include various tires and payloads applied on a total of 21vehicle configurations over three road profiles. These tests assessed the sensitivity of the vehicle’s fuel economy toward rolling resistance and weight. Several experimental results showed inconsistent and counterintuitive trends of the effects of rolling resistance coefficients and weights on fuel economy. The consequences of rolling resistance and vehicle payload are compound and influenced by vehicle speed, road profile, and tire pressure. The irregularities of weight variances’ impact on rolling resistance requires further investigation in the strain level of the tire deformation.
Liao, Gene Y., Card, Brandon, O’Malley, Molly
New Mercedes-Benz Actros loaded with ADAS, active safety tech19TOFHP08_128/1/2019
Mercedes-Benz Trucks, the European arm of the Daimler Trucks business, has launched an updated Actros heavy-duty truck flagship, packed with new technologies, vehicle safety and driver-assistance features. While this fifth-generation Actros may have changed little in outward appearance, there have been significant updates under the skin. Active Drive Assist, MirrorCam and Active Brake Assist 5 are all new, along with updates to Sideguard Assist and Predictive Powertrain Control. Actros comes with a new multimedia cockpit and is the first truck on European roads to replace conventional rearview mirrors with a camera and screen system, called MirrorCam.
Gilkes, Dan
Cleaner Trucks Initiative starts NOx-reduction journey19TOFHP06_126/1/2019
The U.S. Environmental Protection Agency (EPA) is in the beginning stages of establishing new NOx regulations for heavy-duty on-highway trucks. The agency is spurred by advances in technology and a desire to streamline the certification process. The EPA last revised NOx standards for on-road heavy-duty trucks and buses in January 2001. The process that culminated in those standards actually started in the late 1990s. Rulemaking takes time, both to understand technology trends and incorporate a wide group of stakeholders. It will take no less time to update those NOx standards under the program called the Cleaner Trucks Initiative (CTI), announced by the EPA in November 2018.
Morey, Bruce
HYDROGEN BOOM!19TOFHP06_056/1/2019
Nikola reveals Two and Tre fuel-cell trucks and its H2 fueling roadmap, as well as battery-electric military and powersports vehicles. On-highway Class 6-8 trucks are Nikola's main business and engineering focus, but the Arizona-based startup is expanding its product range to include powersports and military sectors to demonstrate its technology's adaptability. In addition to the Nikola Two and Tre hydrogen fuel-cell trucks for North America and Europe, respectively, the manufacturer revealed a battery-electric all-terrain vehicle, an autonomous-capable military vehicle and a personal-watercraft concept to about 2,000 attendees of the Nikola World opening event in Scottsdale, Ariz., near the company's Phoenix headquarters. Nikola plans to offer battery-electric variants of its two day-cab semi-trucks, but CEO Trevor Milton expects hydrogen fuel cells to account for at least 80% of its business.
Gehm, Ryan
Rearview cameras COME INTO SIGHT19TOFHP06_066/1/2019
Momentum is building behind replacing mirrors with camera monitor systems as the technology edges closer to regulatory approval. To borrow from a well-known automotive phrase, “Objects in mirror” aren't really closer than they appear-because the mirror itself appears poised to become another relic of the analog age. Long-debated since the technology quickly became more sophisticated and less costly, camera systems to replace external rearview mirrors for trucks and other on- and off-road commercial vehicles are likely just around the corner. With surprisingly little fanfare last December, the Federal Motor Carrier Safety Admin. (FMCSA) granted a 5-year exemption for on-road commercial vehicles to install Stoneridge Inc.'s MirrorEye Camera Monitor System (CMS) in place of conventional mirrors. It's been off to the races since, as Stoneridge and other rearview-camera developers sense that unconditional change to FMCSA's current commercial-vehicle mirror regulation is next.
Visnic, Bill
EDITORIAL: Diesel's doing just fine, thank you19TOFHP06_086/1/2019
Alternative propulsion features prominently in this issue, starting from the cover shot of Nikola's sleek fuel-cell electric Class 8 tractor, the Two, and continuing into the annual Executive Viewpoints series of articles, in which experts discuss the challenges and opportunities in a range of technology areas, including biomethane and hybrid power systems. Hydrogen as an alt fuel is gaining momentum, particularly for long-haul trucking applications. As CEO Trevor Milton said during the Nikola World extravaganza in April, “We need to be able to go long distances. That's where hydrogen really shines,” (see pg. 24).
Gehm, Ryan
SAE launches Office of Automation19TOFHP06_116/1/2019
Office of Automation director Edward Straub describes the unit as “a first effort to deal with the broad and cross-disciplinary nature of automated vehicles.” Vital SAE activities under way include Standards Committees that are addressing aspects of automation; professional education, messaging and public education; and a growing number of industry and public demonstrations of AVs.
Shuttleworth, Jennifer
Bullish on biomethane19TOFHP06_016/1/2019
The CEO of CNH Industrial says biomethane is cleaner path than electric, as Case demos the alt fuel in cool wheel-loader concept. Hybrid and electric powertrains were omnipresent at bauma 2019 in Munich, with several OEMs and engine manufacturers showcasing electrified machines in near-production form. But CNH Industrial bucked that trend, touting the many benefits of biomethane instead. “Everybody talks about electrification; however, we believe that on the on-highway side as well as in off-highway there is a ‘bridging technology’ that is here to stay-LNG and CNG (liquefied and compressed natural gas),” said Hubertus M. Mühlhäuser, CEO of CNH Industrial, which includes brands Case, New Holland, Iveco and FPT Industrial, among others.
Gehm, Ryan
SAE Truck & Off-Highway Engineering: June 201919TOFHP066/1/2019
Bullish on biomethane The CEO of CNH Industrial says biomethane is cleaner path than electric, as Case demos the alt fuel in cool wheel-loader concept. Unique hybrids required Power systems expert at Perkins stresses that on-highway electric solutions cannot be directly applied to the more-rugged and varied applications in off-highway. Getting driverless trucks onto roadways Autonomous developers at TuSimple address many technical issues, but they also must consider regulations and operating modes. Stronger, quieter cabs Worthington expert sees AHSS and active noise cancellation making off-highway cabs safer and less-stressful places to work. Hydrogen boom! Nikola reveals Two and Tre fuel-cell trucks and its H2 fueling roadmap, as well as battery-electric military and powersports vehicles. Rearview cameras come into sight Momentum is building behind replacing mirrors with camera monitor systems as the technology edges closer to regulatory approval. Supplier Directory Complete listing of industry suppliers categorized by technology area. Editorial Diesel's doing just fine, thank you. Achieving better power management by optimizing thermal management Security, bandwidth drive over-the-air development SAE launches Office of Automation Cleaner Trucks Initiative starts NOx-reduction journey JCB adds three new X Series crawler excavators Toyota's proven fuel-cell stack reduces cost, complexity in H2 semi-truck Q&A Volvo CE's Calle Skillsäter talks about trialing 5G connectivity in construction
Acceleration Testing of 2000 Van Hool 45 Foot Motor Coach2019-01-04314/2/2019
The time/distance relationship for a motor coach accelerating from a stop is often needed to accurately assess the events leading up to a collision. Several series of tests were conducted to document the low speed acceleration performance of a 45 foot long 2000 Van Hool motor coach equipped with a Cummins ISM engine and an Allison B500 6-speed automatic transmission. These tests included three load configurations and two different acceleration rates, normal and rapid. Data were gathered with a Racelogic VBOX IIIi.
Grimes, Wesley, Balasa, Jonathan, Wilcoxson, Greg
Acceleration Testing of 2011 MCI J4500 45 foot Motor Coach2019-01-04094/2/2019
The time/distance relationship for a motor coach accelerating from a stop is often needed to accurately assess the events leading up to a collision. Several series of tests were conducted to document the low speed acceleration performance of a 45-foot long 2011 MCI J4500 motor coach equipped with a Detroit Diesel Series 60 engine and a ZF AS Tronic 12-speed automatic transmission. These tests included three load configurations and two different acceleration rates, normal and rapid. Data were gathered with a Racelogic VBOX IIIi.
Grimes, Wesley, Wilcoxson, Greg, Balasa, Jonathan
Two Phase Heavy Truck Acceleration Model2019-01-04114/2/2019
There have been several papers published over the past 25 years regarding the acceleration of heavy trucks, including different loading conditions, drivetrain configurations, and driving techniques. The papers provide a large data set that measures the speed, distance, and time of the vehicles during acceleration testing and present the data in tabular or graphical formats. Although the data as presented can be useful, it can be challenging to pore over all the data to determine the correct set for a specific application in accident reconstruction. As of this paper’s date of publication, there are approximately eight relevant papers with a total of 268 acceleration tests performed, spanning many years. This paper reviews all the available published literature and summarizes the relevant data in a comprehensive list of accelerations for different heavy truck configurations, which provides a valuable resource to the accident reconstruction field.
Danaher, David, McDonough, Sean, Donaldson, Drew
Modeling of Close-Coupled SCR Concepts to Meet Future Cold Start Requirements for Heavy-Duty Engines2019-01-09844/2/2019
The low-NOx standard for heavy-duty trucks proposed by the California Air Resources Board will require rapid warm-up of the aftertreatment system (ATS). Several different aftertreatment architectures and technologies, all based on selective catalytic reduction (SCR), are being considered to meet this need. One of these architectures, the close-coupled SCR (ccSCR), was evaluated in this study using two different physics-based, 1D models; the simulations focused on the first 300 seconds of the cold-start Federal Test Procedure (FTP). The first model, describing a real, EuroVI-compliant engine equipped with series turbochargers, was used to evaluate a ccSCR located either i) immediately downstream of the low-pressure turbine, ii) in between the two turbines, or iii) in a by-pass around the high pressure turbine. These simulations indicate that the location downstream of the low-pressure turbine offers nearly the best NOx conversion, and that the optimal volume of the ccSCR in this location is 25% of a conventional SCR catalyst. The second model describes a conventional heavy-duty aftertreatment system, to which a ccSCR was added. This model was used to examine the performance of the ccSCR in the context of the full ATS. Optimization of the diesel oxidation catalyst (DOC) and SCR catalyst designs in this system was considered, as well as the use of an NH3 storage-based control strategy for DEF dosing to the SCR catalysts.
Harris, Thomas Miller, Mc Pherson, Kristoffer, Rezaei, Reza, Kovacs, David, Rauch, Hendrik, Huang, Yinyan
Analysis of the Effect of Vehicle Platooning on the Optimal Control of a Heavy Duty Engine Thermal System2019-01-12594/2/2019
One promising method for reducing fuel consumption and emissions, particularly in heavy duty trucks, is platooning. As the distance between vehicles decreases, the following vehicles will experience less aerodynamic drag on the front of the vehicle. However, reducing the velocity of the air contacting the front of the vehicle could have adverse effects on the temperature of the engine. To compensate for this effect, the energy consumption of the engine cooling system might increase, ultimately limiting the overall improvements obtained with platooning. Understanding the coupling between drag reduction and engine cooling load requirement is key for successfully implementing platooning strategies. Additionally, in a Connected and Automated Vehicle (CAV) environment, where information of the future engine load becomes available, the operation of the cooling system can be optimized in order to achieve the maximum fuel consumption reduction. In this paper, a control-oriented physics-based model for the engine cooling loop of a Volvo engine is developed and validated against road data. Starting from the validated model, an optimal control problem for the coolant system is formulated considering the tradeoff between the tracking of the engine temperature setpoint and the corresponding fuel consumption under different trailing distances. To compare the coolant system performance, Dynamic Programming (DP) is used to determine the global optimal solution for the coolant system actuator. The coupling between optimal cooling system operation and reduction in ram air are evaluated by comparing the results obtained from the DP under different platooning conditions against the unrestricted scenario. In addition, the paper analyzes the changes in the tradeoff between fuel consumption and setpoint tracking for different vehicle distances. This analysis will provide useful insight on the sensitivity of the coolant system controller calibration to the platoon distance.
Block, Brian, Huynh, Brian, Boyle, Stephen, Stockar, Stephanie, Geyer, Stephen, Li, Jian, Huber, Jeffrey
An Investigation of the Influence of Close-Proximity Traffic on the Aerodynamic Drag Experienced by Tractor-Trailer Combinations2019-01-06484/2/2019
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 suggest that vehicle shape optimization strategies may differ if the influence of wake effects from surrounding traffic is included in product development cycles. Additionally, truck-platooning benefits should be taken in the context of typical traffic scenarios for which trucks are already experiencing a background-platooning effect and therefore may not be expected to attain the benefits relative to isolate-vehicle conditions.
McAuliffe, Brian, Ahmadi-Baloutaki, Mojtaba
A Generalized Component Efficiency and Input-Data Generation Model for Creating Fleet-Representative Vehicle Simulation Cases in VECTO2019-01-12804/2/2019
The Vehicle Energy Consumption calculation Tool (VECTO) is used for the official calculation and reporting of CO2 emissions of HDVs in Europe. It uses certified input data in the form of energy or torque loss maps of driveline components and engine fuel consumption maps. Such data are proprietary and are not disclosed. Any further analysis of the fleet performance and CO2 emissions evolution using VECTO would require generic inputs or reconstructing realistic component input data. The current study attempts to address this issue by developing a process that would create VECTO input files based as much as possible on publicly available data. The core of the process is a series of models that calculate the vehicle component efficiency maps and produce the necessary VECTO input data. The process was applied to generate vehicle input files for rigid trucks and tractor-trailers of HDV Classes 4, 5, 9 and 10. Subsequently, evaluating the accuracy of the process, the simulation results were compared with reference VECTO results supplied by various vehicle manufacturers. The results showed that the difference between simulated and reference CO2 emissions was on average -0.6% in the Long Haul cycle and 1% in the Regional Delivery. Such a process could be a powerful tool for calculating HDV CO2 emissions for development and analysis purposes, e.g. for new vehicle prototypes or multistage vehicles, and for creating VECTO equivalent models that can be used to assess alternative operating conditions and mission profiles of existing vehicle models. The methodology was applied for creating input of various components in the US tool for HDV certification, GEM, for generic sample-vehicle models available.
Zacharof, Nikiforos, Tansini, Alessandro, Prado Rujas, Iker, Grigoratos, Theodoros, Fontaras, Georgios
Aerodynamic Characteristics Simulation of Heavy Commercial Vehicles Passing through Expressway Tunnel in Cross Wind2019-01-06664/2/2019
Considering the aerodynamic characteristics of the vehicle traveling under the crosswind and the complexity of the flow field change, this paper uses overset mesh of STAR CCM+ software to carry out CFD simulation analysis on the aerodynamic characteristics of heavy commercial vehicles passing through the highway tunnel of which entrance and exit exist crosswind. Corresponding aerodynamic coefficients and flow field changes around the body at different crosswind speeds and different tunnel forms are monitored. The results show that the yaw moment is sensitive to the speed of crosswind. When a heavy commercial vehicle passes through a tunnel where crosswind increases from 10m/s to 13m/s,the yaw moment change rate increases from 34.8 kN•m/s to 45.9 kN•m/s. It also can be seen in these results is that when passing through two tunnels with a distance, the heavy commercial vehicle’s side force, roll moment and yaw moment change because of the surrounding periodic variation of flow field.
Ma, XiaoJing, Miao, ZhenHua, Ma, Jiayi, Zhang, Zhe, Ren, Linlin, Zhang, Yingchao
FCA debuts new Ram Heavy Duty pickups19AUTP03_163/1/2019
FCA's Ram truck division unveiled its new 2019 Heavy Duty (HD) pickup truck lineup at the 2019 North American International Auto Show (NAIAS). The new HD pickups feature the slick interiors and tech from Ram's new 1500 line, significant powertrain and chassis upgrades and all-new front and rear sheetmetal. The Ram HD lineup will face off against Chevy's new HD pickup offerings and Ford's established F-Series and includes 2500/3500 capacities in regular, crew and mega-cab configurations. Since it's a heavy-duty truck launch, Ram is of course touting new capability figures for its HD lineup, which retains its basic cab architecture, but sees nearly every other part of its chassis upgraded. A new 6.7-liter turbo-diesel producing 1,000 lb·ft of torque-the first HD pickup to break the fourfigure torque-output barrier-combines with a redone frame that's now 98.5% high-strength steel to provide what Ram claims are class-leading figures of 35,100-lb (15,921-kg) towing and 7,680-lb (3,565-kg) of payload.
Seredynski, Paul
Heavy Duty Truck and Bus Electrical Circuit Performance Requirement for 12/24-Volt Electric Starter MotorsJ3053_201901 (Current)1/31/2019
The scope of this SAE Recommended Practice is to describe a design standard to define the maximum recommended voltage drop for starting motor main circuits, as well as control system circuits, for 12- through 24-V starter systems.
Truck and Bus Electrical Systems Committee
Introduction to Autonomous Trucking and Platooning TechnologyC191312/19/2018
Vehicle automation and intelligent transportation systems will be the cornerstones of sustainable smart cities of the future. People movers seem to be at the heart of technology development, field trials and on-road testing, and strategic business partnerships when it comes to connectivity and automated driving. Majority of the focus has been on unmanned operation and door-to-door service in urban environments and not on highways. Highways are relatively simpler to handle from an engineering stand-point, but vehicles typically operate at higher speeds, so the cost of accidents is worse. This is very applicable for Class 8 trucks that are hauling loads (i.e., heavy), big, and fast. At the same time, most of the truck maneuvering, especially on highway is pretty straightforward (i.e., maintaining a highway lane, usually the slowest one, with limited lane change maneuvers). It is also easy to contemplate how automating buses (where the routes are fixed) or construction equipment (in confided areas) make sense from a safety and economics point-of-view. This leads to the “Heavy metal first” hypothesis, where we explore why automation in the heavy-duty sector and industrial machines may happen sooner. Some truck OEMs and technology companies have been exploring truck automation. While some have explored concepts such as truck platooning (automated driving with a human in the cab), others have been testing fully autonomous trucks in customer operations. This course is intended to cover the basics of connected automation and provide a ringside view of everything happening in the area of truck automation with special focus on platooning including, but not limited to technology development, field trials, opportunities, and challenges facing the wide scale deployment of such systems.By attending this seminar, you will be able to: Recognize application scenarios for platooning to trucks and buses Appreciate the synergy between connectivity and automated driving systems Gain a solid understanding of the relationship between the different levels of vehicle automation Develop the ability to appreciate the impacts of automation on existing business operations Identify the complications with safely introducing automation on public roads 2 Days CEUs
Fifth Wheel Kingpin, Heavy Duty - Commercial Trailers and SemitrailersJ848_201812 (Current)12/17/2018
This SAE Recommended Practice applies to fifth wheel kingpins for heavy-duty commercial trailers and semitrailers, used for off-highway operation or in hauling heavy loads (see Figure 1).
Truck and Bus Total Vehicle Steering Committee
Cybersecurity Considerations for Heavy Vehicle Event Data Recorders11-01-02-000612/14/2018
Trust in the digital data from heavy vehicle event data recorders (HVEDRs) is paramount to using the data in legal contests. Ensuring the trust in the HVEDR data requires an examination of the ways the digital information can be attacked, both purposefully and inadvertently. The goal or objective of an attack on HVEDR data will be to have the data omitted in a case. To this end, we developed an attack tree and establish a model for violating the trust needed for HVEDR data. The attack tree provides context for mitigations and also for functional requirements. A trust model is introduced as well as a discussion on what constitutes forensically sound data. The main contribution of this article is an attack tree-based model of both malicious and accidental events contributing to compromised event data recorder (EDR) data. A comprehensive list of mitigations for HVEDR systems results from this analysis.
Daily, Jeremy, Gardiner, Ben
Physical Layer, 250 Kbps, Un-Shielded Twisted Pair (UTP)J1939/15_201812 (Current)12/14/2018
This document describes a physical layer utilizing Unshielded Twisted Pair (UTP) cable with extended stub lengths for flexibility in ECU placement and network topology. Also, connectors are not specified. CAN controllers used on SAE J1939-15 networks must be restricted to use only Classical Frames as defined in ISO 11898- 1. A network which may have legacy controllers cannot tolerate FD Frames. These SAE Recommended Practices are intended for light- and heavy-duty vehicles on- or off-road as well as appropriate stationary applications which use vehicle derived components (e.g., generator sets). Vehicles of interest include, but are not limited to: on- and off-highway trucks and their trailers; construction equipment; and agricultural equipment and implements.
Truck Bus Control and Communications Network Committee
Are higher voltage architectures imminent?18TOFHP10_0610/1/2018
As the limitations of current 12V architectures become more apparent, the commercial vehicle industry could be on the verge of adopting 48V. The only question is, will improvements in other technologies offer something better? “I have never seen such momentum behind the current move towards higher voltage architectures in my 32 years' experience in this industry,” said Carl R. Smith, Commercial Manager, Sales, Applications Engineering and Customer Support for Eaton eMobility. “This is in commercial vehicles, construction and agricultural machines as well as in passenger cars.” For those of us of a certain age, we have seen this before. In the late 1990s through 2000 or so, there was another initiative to upgrade electrical systems to a nominal 42V. That fizzled.
Morey, Bruce
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