Medium-duty Trucks Research Articles

Energy assessment of an electrically heated catalyst in a hybrid RCCI truck

Reactivity controlled compression ignition (RCCI) combustion showed great advantages in terms of engine-out NOx and soot emissions reduction. However, HC and CO emissions are larger than with conventional diesel combustion. Commercial oxidation catalysts can deal with the amount of HC and CO generated during the RCCI combustion only at warm conditions, thus limiting the implementation of this concept in conventional vehicles and in RCCI hybrid applications due to the large engine stop periods. This work aims to study the behaviour of an electrically heated catalyst used in a hybrid medium-duty truck operating with diesel-gasoline RCCI combustion. A parallel P2 full hybrid medium-duty truck is studied in transient conditions by means of numerical simulations validated with experimental data. The results are compared to those from the commercial diesel non-hybrid truck and the RCCI non-hybrid concept with a commercial oxidation catalyst. The results show that the fuel consumption increases about 2 % in combined cycles and 5 % in urban cases with respect to the non-hybrid RCCI case with a commercial oxidation catalyst. Finally, it was found that the RCCI hybrid concept with the electrically heated catalyst allows to achieve the EUVI targets for all the pollutant emissions with CO2 levels of 15 %.

Full-Scale Experimental Study of a Reinforced Concrete Bridge Pier under Truck Collision

Recently, vehicle collisions with bridge piers have occurred frequently, which have attracted the attention of researchers. However, as one of the most important research methods, vehicle collision tests for reinforced concrete (RC) bridge piers are limited. The impact responses and damage characteristics of full-scale RC piers have seldom been studied in actual truck collision tests, which hinders further development in this research area. Therefore, a medium-duty truck will be employed to carry out a full-scale crash test on an RC single-column pier 1 m in diameter in this study. The crashing truck had a mass of 7.76 t and a collision speed of 81 km/h. The damage and failure level of the vehicle and RC pier will be examined, and some critical data will be obtained from the test, such as the displacement, velocity, and acceleration time histories of the truck, and the deflection, acceleration, and reinforcement strain time histories of the RC pier. In addition, based on the accelerations of the cargo box and engine, the vehicular impact forces will be derived approximately and discussed. This will provide valuable experimental data for the study of vehicular collisions with RC bridge piers, especially in the calibration and validation of the finite element (FE) models for truck collisions and the impact resistance evaluation of RC bridge piers.

Mortality-based damages per ton due to the on-road mobile sector in the Northeastern and Mid-Atlantic U.S. by region, vehicle class and precursor

On-road vehicular emissions contribute to the formation of fine particulate matter and ozone which can lead to increased adverse health outcomes near the emission source and downwind. In this study, we present a transportation-specific modeling platform utilizing the community multiscale air quality model (CMAQ) with the decoupled direct method (DDM) to estimate the air quality and health impacts of on-road vehicular emissions from five vehicles classes; light-duty autos, light-duty trucks (LDT), medium-duty trucks, heavy-duty trucks (HDT), and buses (BUS), on PM2.5 and O3 concentrations at a 12 × 12 kilometer scale for 12 states and Washington D.C. as well as four large metropolitan statistical areas in the Northeast and Mid-Atlantic U.S. in 2016. CMAQ-DDM allows for the quantification of sensitivities from individual precursor emissions (NO, SO2, NH3, volatile organic compounds, and PM2.5) in each state to pollution levels and health effects in downwind states. In the region we considered, LDT are responsible for the most PM2.5-attributable premature mortalities at 1234 with 46% and 26% of those mortalities from directly emitted primary particulate matter and NH3, respectively; and O3-attributable premature mortalities at 1129 with 80% of those mortalities from NO emissions. Based on a detailed source-receptor matrix of sensitivities with subsequent monetization of damages that we computed, we find that the largest damages-per-ton estimate is approximately $4 million per ton of directly emitted primary particulate matter from BUS in the New York-Newark-Jersey City metropolitan statistical area. We find that on-road vehicular NH3 emissions are the second largest contributor to PM2.5 concentrations and health impacts in the study region, and that reducing 1 ton of NH3 emissions from LDT is ∼75 times and from HDT is ∼90 times greater in terms of damages reductions than a 1 ton reduction of NO. By quantifying the impacts by each combination of source region, vehicle class, and emissions precursor this study allows for a comprehensive understanding of the largest vehicular sources of air quality-related premature mortalities in a heavily populated part of the U.S. and can inform future policies aimed at reducing those impacts.

Modelling Fuel Consumption andNOₓEmission of a Medium Duty Truck Diesel Engine With Comparative Time-Series Methods

This study focuses on different intelligent time series modelling techniques namely nonlinear autoregressive network with exogenous inputs (NARX), autoregressive integrated moving average with external inputs (ARIMAX), multiple linear regression (MLR), and regression error with autoregressive moving average (RegARMA), applied on a diesel engine to predict NO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> emission and fuel consumption. The experiment data are collected from a six cylinder, four stroke medium duty truck diesel engine, which is integrated on a passenger bus and operated in engine integration tests. NO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> emission and fuel consumption outputs are estimated with the help of input data; exhaust gas recirculation temperature and position, engine coolant temperature, engine speed, exhaust gas pressure, common rail pressure, intake manifold air temperature and pressure, accelerator pedal percentage, engine load, turbocharger variable geometry position and speed, and selective catalytic reduction outlet temperature. NARX artificial time series neural network, MLR, ARIMAX, and RegARMA time series techniques were separately applied for the estimation NO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> emission and fuel consumption outputs. The performance of the models is analyzed and evaluated with Bayesian information criterion (BIC) and root mean square error (RMSE) criteria. When the high cost and time loss of experimental testing are thought, using the intelligent modelling methodology provides far more accurate prediction and fast application abilities to analyze internal combustion engine dynamics for the control and calibration manner. As a result of the comparison of different types of modelling techniques, RegARMA technique comes to the forefront with 6707.6 BIC value with 105.58 RMSE for NO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> emission model and 4026.4 BIC value with 7.93 RMSE for fuel consumption model.

Medium duty truck quality circle to reduce defect per unit in overall cab in white

Medium duty truck quality circle to reduce defect per unit in overall cab in white

Sensitivity of a vehicle lane change control system to disturbances and measurement signal errors – Modeling and numerical investigations

Automatic control of the lane change process forms a basis to automate more complex vehicle maneuvers. The lane change controller model presented in the paper has a mixed structure. In the open-loop structure, the controller works as a reference signals generator supplying a time course of the steering system angle (reference input signal), and two time courses of the lateral and angular shifts of the vehicle (reference output signals). In the closed-loop structure it works as a steering signal corrector (regulation based on the error signals between the reference and measured signals expressing vehicle trajectory). For the validation of the controller algorithm, extensive simulation investigations have been carried out. In these investigations, as a virtual control object, a very detailed and experimentally verified mathematical model of a medium-duty truck has been used. The control system model and its simulation investigations were already presented in several papers by the Authors. This paper presents the results of the research focused on the sensitivity of the control system to disturbances and measurement signal errors (noises, offsets, delays).

Comparison of economic viability of series and parallel PHEVs for medium-duty truck and transit bus applications

This article performs a novel comparison of the life-cycle costs of the series and parallel architectures for plug-in hybrid electric vehicles. Economic viability is defined as having a payback period less than 2 years and number of battery replacements less than or equal to three over a vehicle life of 12 years along-with drivability and gradability constraints. Economic viability is compared for two plug-in hybrid electric vehicle applications (Medium-duty Truck and Transit Bus) using series and parallel architectures over multiple drivecycles, for three economic scenarios (viz. 2020, 2025 and 2030 where the fuel price, battery price and motor price are varied such that latter scenarios are more favorable for hybridization). One battery overnight recharge is assumed. The results demonstrate that by 2020 the plug-in hybrid electric vehicle transit buses are viable for the duty cycles Manhattan, Orange County, and China (Normal and Aggressive). By 2025, plug-in hybrid electric vehicle Class 6 trucks are viable for all duty cycles considered (Pick-up and delivery, Refuse and New York Composite). The parallel architectures generally require less than 50% of the initial cost of the series architecture, due to smaller motor sizes, driving earlier viability for parallel architectures. The transit bus scenarios generally achieve payback sooner than the medium-duty truck due to higher fuel cost savings, driving earlier viability for transit bus applications.

Evaluation of real-time vehicle energy consumption and related emissions in China: A case study of the Guangdong–Hong Kong–Macao greater Bay Area

The Guangdong–Hong Kong–Macao Greater Bay Area (GBA) was recently proposed by the Chinese government for socioeconomic–political–environmental development. As one of the most important parts for the development of the GBA, the transportation sector has become a nonnegligible consumer of energy and source of emission. Therefore, vehicle energy consumption and related emissions in the GBA must be evaluated. However, an effective framework for accurately estimating the real-time transportation performance, vehicle energy consumption and emission in large urban areas is still lacking. This study aims to develop a novel method for examining the regional integration and the spatial connection that affect vehicle emission via crowdsourced traffic data and an emission model. The novelty of this study is that it explores the acquisition of large-scale and real-time data as well as the calculation of corresponding energy consumption and environmental impact. Based on the analysis of transportation in GBA, it is found that the vehicle energy consumption and emission on the expressway are nearly half as that on the other urban roads. Moreover, a significant difference exists in vehicle energy consumption and emission between passenger cars and medium-duty trucks. Regarding transportation performance, vehicle energy consumption and emissions, they are closely related to departure time. It is also found that most of the adjacent cities tend to have high vehicle energy consumption and emission. The contribution of the Hong Kong–Zhuhai–Macao Bridge to transportation from Hong Kong, Macao and Zhuhai is different. Hong Kong benefits most from the bridge in terms of traffic energy efficiency. This study would be valuable to both researchers and practitioners. It helps researchers apply a large dataset in replicating real-world travel, energy consumption and emission pattern at a large scale. Policymakers and practitioners would benefit from developing effective strategies for the sustainable development of the GBA.

Estimating transboundary economic damages from climate change and air pollution for subnational incentives for green on-road freight

Subnational incentives to adopt zero emission vehicles (ZEVs) are critical for reducing the external economic damages posed by transportation to air quality and the climate. Few studies estimate these damages for on-road freight, especially at scales relevant for subnational policies requiring cross-border cooperation. Here, we assess the damages to US receptors from emissions of air pollutants (PM2.5, NOx, SO2, NH3), and greenhouse gases (CO2, CH4, N2O) from medium and heavy duty freight trucking, and the benefits of ZEV adoption by census division in the Province of Ontario. We develop an integrated modelling framework connecting a travel demand model, a mobile emissions simulator, and a regression based marginal damages model of air pollutants and climate change. We estimate $1.9 billion (2010 USD) in annual cross-border damages, or $0.16/VKT, resulting from scaled up atmospheric emissions from a ‘typical day’ of medium and heavy duty truck traffic volume for Ontario in 2012. This implies approximately $8000 per truck per year in damages, which could inform an economic incentive for emission reduction. The provincial goal of 5% ZEV adoption would reduce GHG emissions in 2012 by 800 ktCO2e, yielding $89 Million (2010 USD) in cross-border benefits annually, with air quality co-benefits of $83/tCO2e. This result varies between −19% and 22% based on sensitivity analysis for travel and emissions models, though economic damages are likely the largest uncertainty source. Such advances in subnational scale integrated modeling of the environmental impacts of freight can offer insights into the sustainable design of clean freight policy and programs.

Potential of using OMEx as substitute of diesel in the dual-fuel combustion mode to reduce the global CO2 emissions

To achieve the targets of extreme low emissions values for the transport sector, several technologies emerged in the last few years. In this sense, advanced combustion modes as the dual-fuel low temperature combustion showed great advantages in terms of NOx and soot emissions reduction. At low and medium engine load, the operation is stable with virtually zero emissions. However, the exhaust gas recirculation rates at high load need to be increased to avoid excessive in-cylinder peaks, which leads to higher soot emissions. At these conditions, the use of non-sooting fuels as the oxymethylene dimethyl ethers (OMEx) allows avoiding the NOx-soot trade-off. In addition, the e-fuel consideration of the OMEx makes it suitable to reduce the global GHG emissions. This paper assesses the potential of using OMEx as high reactivity fuel to reduce the CO2 well-to-wheel emissions, and NOx and soot tailpipe emissions, in a medium-duty truck operating under dual-fuel combustion in transient conditions. The cargo mass was varied between 0% and 100% (18 ton) in the World Harmonized Vehicle Cycle. The tank-to-wheel analysis shows slightly higher CO2 production with OMEx-gasoline than with diesel-gasoline due to the ratio between the lower heating value and the carbon content. However, the well-to-wheel analysis shows the benefits of using OMEx to reduce the carbon dioxide footprint, which ranges from 13% (at full cargo mass) to 19% (at low cargo mass) compared to diesel-gasoline dual-fuel mode. This benefit is due to the large gains in terms of fuel production due to the carbon capture and the clean electric energy source necessary to produce the OMEx.

A Time-Efficiency Study of Medium-Duty Trucks Delivering in Urban Environments

This paper uses data from a major logistics service provider in Gothenburg (Sweden) to (i) identify the different activities in a typical urban distribution tour, (ii) quantify the time required by drivers to perform each of these activities, and (iii) identify potential initiatives to improve time efficiency. To do so, the authors collected GPS data, conducted a time-study of the activities performed by the drivers for a week, conducted a focus group with the drivers, and a set of interviews with managers. The results show that driving represents only 30% of the time, another 15% is spent on breaks, and the remaining 55% is used to perform activities related to customer service, freight handling, and planning. The latter are subdivided into multiple activities, each taking a small amount of time. A focus group with the drivers and some interviews revealed several initiatives to improve time efficiency. Most initiatives can bring small gains, but when aggregating all potential time savings there is a big potential to improve overall time efficiency. Initiatives with highest potential and low cost are: providing better pre-advice on upcoming customers, improving route planning, having hand-free cell phone use, and enhancing handling equipment.

Preparation and carring out of tests to assess the operation modes of a medium-duty cargo vehicle transmission

This article discusses the achievements of Nizhny Novgorod State Technical University n.a. R.E. Alekseev specialists in the field of medium-duty truck Gazon Next testing in order to determine the engine operation modes and mechanical transmission in conditions close to operational. The latest achievements of measuring technologies for assessing the car performance properties are shown. The experimental characteristics obtained are necessary for the mechanical transmission robotic kit development.

Parametric design and regenerative braking control of a parallel hydraulic hybrid vehicle

Hydraulic hybrid technologies improve the fuel economy of city-use medium duty vehicles by recovering braking energy and reusing it for driving, most notably vehicle launching. In this paper, a parametric design of hydraulic driving system for a medium duty truck is conducted based on its power demand in typical urban driving cycles. The braking control strategy is designed considering both the safety regulations and braking energy recovery rate. The proportional relationship of hydraulic pump/motor output torque and its working pressure is considered when designing the braking control strategy. The influence of the high pressure accumulator minimum working pressure and the corresponding gas volume at the minimum pressure on the braking energy recovery rate is analyzed. The simulation results show that the proposed hydraulic driving system and braking control strategy helps greatly increase the braking energy recovery rate. Besides, different vehicle mass and load distributions are investigated to analyze the regenerative braking effect on various loading conditions.

Empirical Investigation on the Effects of Rolling Resistance and Weight on Fuel Economy of Medium-Duty Trucks

Empirical Investigation on the Effects of Rolling Resistance and Weight on Fuel Economy of Medium-Duty Trucks

Analysis and simplified modelling of simulation of tests for medium-duty truck collision with twin anti-ram bollards

An actual test of medium-duty truck collision with twin anti-ram bollards of steel tube is analysed and simulated with different mass-spring-damper models to study bollard design requirements. Test data is obtained from test report of a medium-duty truck crashed into two fixed twin bollards at speed 78.3 km/h. Maximum impact load and impact height at that time is important in the analysis. Bollard height should be close to or larger than the vehicle’s centre of gravity height to avoid climbing of the truck on the bollard. However, increasing impact height yields also increase in failure risk of bollard. Foundation is also critical in success of the bollard in successfully stopping the vehicle. The bollard should be fixed to the frame embedded in the concrete foundation so that the deformation in concrete be minimised. The bollard should be so stiff to stop the vehicle while most of the impact energy is absorbed by the vehicle through deformation of its frontal sections. A single-degree freedom linear mass-spring-damper model is the simplest model, but its results are not in line with test data. Single-degree non-linear model simulates the peak load but not the load history. However, using engine mass instead of truck mass in the single-degree model provides acceptable impact force data for the bollard. Two-degree freedom mass-spring damper linear model seems to simulate both truck’s and bollard’s deformation in a good manner. Non-linear analysis simulates the collision in a more realistic way, but it requires more data to be determined with testing.

An Investigation of the Influence of Close-Proximity Traffic on the Aerodynamic Drag Experienced by Tractor-Trailer Combinations

&lt;div class="section abstract"&gt;&lt;div class="htmlview paragraph"&gt;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.&lt;/div&gt;&lt;/div&gt;

Life Cycle Assessment of Commercial Delivery Trucks: Diesel, Plug-In Electric, and Battery-Swap Electric

The development of electric delivery trucks has attracted much attention in recent years. The purpose of this study is to assess the greenhouse gas (GHG) emissions and the total cost of ownership (TCO) of light-duty and medium-duty diesel trucks (DTs), plug-in electric trucks (ETs), and battery-swap ETs. A simplified life cycle assessment (LCA) method and a TCO assessment method are used. Numerical results show that the average GHG emission of light-duty ETs is 69% lower than that of light-duty DTs, while that of medium-duty ETs is 9.8% higher than that of medium-duty DTs. As regards TCO, those of plug-in ETs and battery-swap ETs are 37.8% lower and 21% higher than that of light-duty DTs, while for medium-duty trucks, the TCO of plug-in and battery-swap ETs are 6.7% lower and 18.9% higher than that of medium-duty DTs. The main conclusion of this paper is that light-duty plug-in ETs exhibit the best performance in terms of cost saving and GHG emission reduction. Moreover, ETs show more advantages than DTs when the frequency of use is higher or when the driving environment is more congested.

A multi-objective multi-item solid transportation problem with vehicle cost, volume and weight capacity under fuzzy environment

Generally, in transportation problem, full vehicles (e.g., light commercial vehicles, medium duty and heavy duty trucks, etc.) are to be booked, and transportation cost of a vehicle has to be paid irrespective of the fulfilment of the capacity of the vehicle. Besides the transportation cost, total time that includes travel time of a vehicle, loading and unloading times of products is also an important issue. Also, instead of a single item, different types of items may need to be transported from some sources to destinations through different types of conveyances. The optimal transportation policy may be affected by many other issues like volume and weight of per unit of product, unavailability of sufficient number of certain types of vehicles, etc. In this paper, we formulate a multi-objective multi-item solid transportation problem by addressing all these issues. The problem is formulated with the transportation cost and time parameters as fuzzy variables. Using credibility theory of fuzzy variables, a chance-constraint programming model is formulated, and is then transformed into the corresponding deterministic form. Finally numerical example is provided to illustrate the problem.

Numerical analysis of collision between a tractor-trailer and bridge pier

Accidents involving collisions of heavy-duty trucks with highway bridge piers occurred occasionally, in which the bridge piers might be subjected to severe damage, and cause the collapse of the superstructure due to the loss of axial loading capacity. The existing researches are mostly concentrated on the light- or medium-duty trucks. This article mainly concerns about the collisions between the heavy-duty trucks (e.g. tractor-trailer) and bridge piers as well as the evaluation of the impact force. First, by modifying the finite element model of Ford F800 single-unit truck, which was developed by National Crash Analysis Center, the finite element model of a tractor-trailer is established. Then, the full-scale tractor-trailer crash test on concrete-filled steel pier jointly conducted by Texas Transportation Institute, Federal Highway Administration, and Texas Department of Transportation is numerically simulated. The impact process is well reproduced and the established model is validated by comparison of the impact force. It indicates that the tractor-trailer impact force time history consists of two or three peaks and the corresponding causes are revealed. Furthermore, the parametric influences on the impact force are discussed, including the diameter and cross section shape of the pier, cargo weight, impact velocity, relative impact position, and vehicle type. Finally, the finite element model of an actual reinforced concrete highway bridge pier is established, and the impact force and lateral displacement of the pier subjected to the impact of the tractor-trailer are numerically derived and discussed.

Methods for Determining and Applications of High-Resolution Vehicle Emission Inventory at County Scale

This study proposes a method for high-resolution vehicle emission inventories at county scale based on field investigations and Google Earth satellite images, using the Tongzhou district of Beijing as an example for data analysis. VKT and the corresponding emissions of each pollutant were calculated using the number of registered vehicles and the real-time traffic volumes, respectively. The results showed that the mileage calculated based on the method using registered vehicles is about 37% less than that based on real-time traffic volumes, with the latter method providing data closer to the actual situation. The mileage for small passenger cars, large passenger vehicles, and medium-duty trucks were underestimated, and that for light trucks, heavy trucks, low-speed trucks were overestimated based on the registered vehicle method. Emissions from small passenger cars were also underestimated by about 51%, using the registered vehicle method. For emissions of large passenger vehicles, light trucks, and medium-duty trucks, there was less difference between the two methods. Based on the registered vehicle method, emissions of heavy trucks, low-speed trucks, and motorcycles were overestimated by about 41%, 30%, and 30%, respectively.