Increasing the on-road fuel economy by trailing at a safe distance

2017 ◽  
Vol 231 (9) ◽  
pp. 1303-1311 ◽  
Author(s):  
John Nuszkowski ◽  
Harlan Smith ◽  
Michael McKinney ◽  
Nicholas McMahan ◽  
Benjamin Wilder ◽  
...  
Keyword(s):  
Fuel Economy ◽  
Energy Demand ◽  
Aerodynamic Drag ◽  
The United States ◽  
Automotive Applications ◽  
Heavy Duty ◽  
Commercial Vehicles ◽  
Safe Distance ◽  
Air Velocity ◽  
Road Load

Energy is a driving force for automotive applications. Reducing the energy demand of the vehicle is one method of increasing the fuel economy of a vehicle. Heavy-duty commercial vehicles have large frontal areas that provide large amounts of aerodynamic drag at highway speeds. Reducing the aerodynamic drag lowers the engine demand and therefore increases the fuel economy of the vehicle. This study tested the fuel economy and the front air velocity of a 10.7 m box truck trailing another box truck by distances of 3.1 times the truck length, 4.7 times the truck length, and 6.3 times the truck length at a highway speed of 28 m/s. The distance of 6.3 times the vehicle length was considered ‘safe’ for trailing another vehicle, whereas the distances of 3.1 times the truck length and 4.7 times the truck length were not considered safe by the United States Fire Administration. The results showed significant reductions in the air velocity in front of the trailing vehicle of 8.5%, 6.5%, and 3.8% for trailing distances of 3.1 times the vehicle length, 4.7 times the vehicle length, and 6.3 times the vehicle length respectively. The fuel economy of the trailing truck increased significantly by 7.4–8.0%, 8.2–9.0%, and 6.5%–7.7%, for trailing distances of 3.1 times the vehicle length, 4.7 times the vehicle length, and 6.3 times the vehicle length respectively. Based on a road load analysis, these fuel economy improvements indicated a reduction in the drag coefficient of the trailing vehicle of 8–10%. Therefore, a box truck trailing another box truck at a safe distance results in a reduction in the aerodynamics drag and a significant increase in the fuel economy.

Numerical Simulation on Aerodynamic Characteristics of Heavy-Duty Commercial Vehicle

2011 ◽  
Vol 346 ◽  
pp. 477-482 ◽  
Author(s):  
Zhe Zhang ◽  
Ying Chao Zhang ◽  
Jie Li ◽  
Jia Wang
Keyword(s):  
Numerical Simulation ◽  
Fuel Economy ◽  
High Speed ◽  
Aerodynamic Drag ◽  
Aerodynamic Characteristics ◽  
National Standards ◽  
Heavy Duty ◽  
Commercial Vehicles ◽  
Automotive Technology ◽  
New Research

With the development of automotive technology and high-speed highway construction, the speed of the vehicles increase which cause the significant increase in the aerodynamic drag when road vehicles are moving. Thereby the power of the vehicles, fuel economy, operational stability and other properties are affected very seriously. Heavy-duty commercial vehicles as the most efficient way to transport goods on the highway are widely used, and the speed of the vehicles increases faster. Especially the demands for heavy-duty commercial vehicles are increasing in recent years. Reducing the aerodynamic drag by the analysis of external aerodynamic characteristics, improving the fuel economy and reducing energy consumption have become new research topics of heavy-duty commercial vehicles. To make the heavy-duty commercial vehicles meet the national standards of energy saving, a simplified heavy-duty commercial truck model was built in this paper. The numerical simulation of the vehicle was completed based on the theory of the aerodynamics. The aerodynamic characteristics were analyzed, according to the graphs of the pressure distribution, velocity distribution and flow visualization. To improve the aerodynamic characteristics of heavy-duty commercial vehicles, the main drag reduction measures are reducing the vortex of the cab and the container, the end of the container and the bottom of the container.

Failure mode investigation and re-design of heavy-duty commercial vehicle bogie bracket

2019 ◽  
Vol 43 (3) ◽  
pp. 405-415
Author(s):  
P. Thangapazham ◽  
L.A. Kumaraswamidhas ◽  
D. Muruganandam
Keyword(s):  
Maximum Stress ◽  
Suspension System ◽  
Heavy Duty ◽  
Commercial Vehicles ◽  
Road Load ◽  
Road Surfaces ◽  
Strain Data ◽  
Critical Sections ◽  
Bracket Base ◽  
Base Design

Heavy-duty commercial vehicles play a significant role in commodity logistics. For each of these vehicles, the suspension is the most essential system to support the load and road shock. Bogie type suspension system is employed to safeguard the vehicle from road shock. The bogie bracket is a juncture between the chassis and the axle in the suspension system. The bogie bracket has been identified as a critical part of the suspension system. In the present study, bogie bracket base design and modelling was performed using computer-aided engineering (CAE). The strength of the bogie was tested to identify weaker sections. Design modifications were performed to improve the strength on identified critical sections through reinforcement techniques. A road load data acquisition (RLDA) test was conducted under different road conditions to validate CAE results. Five different rough-road road surfaces were chosen for RLDA testing. Using strain gauges, strain data were acquired during the test. Corresponding stress values were obtained and maximum stress was found in all driving conditions. For the base design bogie bracket, under RLDA test, crack initiation and crack propagation were identified under vertical loads. A reinforced bogie bracket was designed and found to have a higher strength and longer expected life than that of the base design.

Reduced Aerodynamic Drag for Truck-Trailer Configurations Using Parametrized CFD Studies

2012 ◽  
Author(s):  
Srdan Pavlović ◽  
Magnus Andersson ◽  
Jonas Lantz ◽  
Matts Karlsson
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Drag Reduction ◽  
Conceptual Design ◽  
Fuel Economy ◽  
Aerodynamic Drag ◽  
Foreseeable Future ◽  
Heavy Duty ◽  
Computational Fluid Dynamics Cfd

In the presented work, two studies using Computational Fluid Dynamics (CFD) have been conducted on a generic truck-like model with and without a trailer unit at a speed of 80 km/h. The purpose is to evaluate drag reduction possibilities using externally fitted devices. A first study deals with a flap placed at the back of a rigid truck and inclined at seven different angles with two lengths. Results show that it is possible to decrease drag by 4%. In a second study, the flap has been fitted on the tractor and trailer units of a truck-trailer combination. Four settings were surveyed for this investigation, one of which proved to decrease drag by up to 15%. A last configuration where the gap between the units has been closed has also been evaluated. This configuration offers a 15% decrease in drag. Adding a flap to the closed gap configuration decreases drag by 18%. New means of reducing aerodynamic drag of heavy-duty (HD) vehicles will be important in the foreseeable future in order to improve the fuel economy. The possibilities of reducing drag are prevalent using conceptual design.

Alstom Gas Turbine Technology Overview: Status 2014

2015 ◽  
Author(s):  
Wolfgang Kappis ◽  
Stefan Florjancic ◽  
Uwe Ruedel
Keyword(s):  
Power Generation ◽  
Gas Turbine ◽  
Gas Turbines ◽  
New Technologies ◽  
The United States ◽  
Heavy Duty ◽  
Fuel Flexibility ◽  
Market Requirements ◽  
Base Load ◽  
Very High

Market requirements for the heavy duty gas turbine power generation business have significantly changed over the last few years. With high gas prices in former times, all users have been mainly focusing on efficiency in addition to overall life cycle costs. Today individual countries see different requirements, which is easily explainable picking three typical trends. In the United States, with the exploitation of shale gas, gas prices are at a very low level. Hence, many gas turbines are used as base load engines, i.e. nearly constant loads for extended times. For these engines reliability is of main importance and efficiency somewhat less. In Japan gas prices are extremely high, and therefore the need for efficiency is significantly higher. Due to the challenge to partly replace nuclear plants, these engines as well are mainly intended for base load operation. In Europe, with the mid and long term carbon reduction strategy, heavy duty gas turbines is mainly used to compensate for intermittent renewable power generation. As a consequence, very high cyclic operation including fast and reliable start-up, very high loading gradients, including frequency response, and extended minimum and maximum operating ranges are required. Additionally, there are other features that are frequently requested. Fuel flexibility is a major demand, reaching from fuels of lower purity, i.e. with higher carbon (C2+), content up to possible combustion of gases generated by electrolysis (H2). Lifecycle optimization, as another important request, relies on new technologies for reconditioning, lifetime monitoring, and improved lifetime prediction methods. Out of Alstom’s recent research and development activities the following items are specifically addressed in this paper. Thermodynamic engine modelling and associated tasks are discussed, as well as the improvement and introduction of new operating concepts. Furthermore extended applications of design methodologies are shown. An additional focus is set ono improve emission behaviour understanding and increased fuel flexibility. Finally, some applications of the new technologies in Alstom products are given, indicating the focus on market requirements and customer care.

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