scholarly journals Effect of Speed and Boot Opening on Aerodynamics, Fuel Consumption, and CO2 Emission of Minibus

2021 ◽  
Vol 6 (4) ◽  
Author(s):  
Olusola A. Oloruntoba ◽  
Adebunmi P. Okediji
Keyword(s):  
Fuel Consumption ◽  
Co2 Emission ◽  
Regression Models ◽  
Viscous Drag ◽  
Vehicle Speed ◽  
Road Accidents ◽  
Total Drag ◽  
Pressure Drag ◽  
Regulatory Bodies ◽  
Excess Load

Overspeeding   and overloading contribute to road accidents. In developing countries, overloading is often indicated by open boot due to commercial transporters’ motivation to carry an excess load to boost revenue. Therefore, there is a need to provide measures to control or eliminate the practice of overspeeding and overloading. This study aims to conduct a parametric study to determine the effect of vehicle speed and boot opening on the aerodynamics of airflow around a typical minibus, fuel consumption, and CO2 emission, and recommend optimum boot opening. Computational Fluid Dynamics is employed using the FLUENT™ program. Results show the existence of a wavy pattern for drag coefficient, fuel consumption, and CO2 emission concerning boot opening. Furthermore, two boot opening regions exist:  and . The first region exhibits low prediction error (maximum of 7.25%) and better fit of regression model to FLUENT™ data. The first region also has lower susceptibility to exhibit handling instability. Therefore, boot opening around  is recommended as the optimum boot opening, to ensure minimum fuel consumption and CO2 emissions, improve handling and safety. The developed regression models could inform regulatory bodies’ formulation and implementation of policies to mitigate road accidents. Keywords—Boot Opening, CO2 emission, Fuel Consumption, Pressure drag, Total Drag, Minibus, Viscous Drag

Characteristics of Multi-Cavity Trapped Vortex Combustors

2010 ◽  
Author(s):  
Alejandro M. Briones ◽  
Balu Sekar
Keyword(s):  
Heat Release ◽  
Temperature Profile ◽  
Viscous Drag ◽  
Reacting Flow ◽  
Total Drag ◽  
Pressure Drag ◽  
Air Jets ◽  
Exit Temperature ◽  
Trapped Vortex ◽  
Single Cavity

This research is motivated towards improving and optimizing the performance of AFRL’s Inter-Turbine Burner (ITB) in terms of greater combustion efficiency, reduced losses and exit temperature profile requirements. The ITB is a minicombustor concept, situated in between the high and low pressure turbine stages and typically contains multiple fueled and non-fueled Trapped Vortex Combustor (TVC) cavities. The size, placement, and arrangement of these cavities have tremendous effect on the combustor exit temperature profile. The detailed understanding of the effect of these cavities in a three-dimensional ITB configuration would be very difficult and computationally prohibited. Therefore, a simple but somewhat similar conceptual axi-symmetric burner is used here the design variations of Trapped Vortex Combustor (TVC) through modeling and simulation. The TVC can be one single cavity or can be represented by multi-cavity combustor. In this paper, both single cavity TVC and multi-cavity TVCs are studied. The single cavity TVC is divided into multiple cavities while the total volume of the combustor remains constant. Four combustors are studied: Baseline, Staged, Three-Staged, and Interdigitated TVC. An extensive computational investigation on the characteristics of these multi-cavity TVCs is presented. FLUENT is used for modeling the axisymmetric reacting flow past cavities using a global eddy dissipation mechanism for C3H8-air combustion with detailed thermodynamic and transport properties. Calculations are performed using Standard, RNG, and Realizable k-ε RANS turbulence models. The numerical results are validated against experimental temperature measurements on the Base TVC. Results indicate that the pressure drag is the major contributor to total drag in the Base TVC. However, viscous drag is still significant. By adding a concentric cavity in sequential manner (i.e. Staged TVC), the pressure drag decreases, whereas the viscous drag remains nearly constant. Further addition of a secondary concentric cavity (i.e. Three-Staged TVC), the total drag does not further decrease and both pressure and viscous drag contributions do not change. If instead a non-concentric cavity is added to the Base TVC (i.e. Interdigitated TVC), the pressure drag increases while the viscous drag decreases slightly. The effect of adding swirl flow is to increase the fuel-air mixing and as a result, it increases the maximum exit temperature for all the combustors modeled. The jets and heat release contribute to increase pressure drag with the former being greater. The fuel and air jets and heat release also modify the cavity flow structure. By turning off the fuel and air jets in the Staged TVC, lower drag (or pressure loss) and exit temperature are achieved. It is more effective to turn off the fuel and air jets in the upstream (front) cavity in order to reduce pressure losses. Based on these results, recommendations are provided to the engineer/designer/modeler to improve the performance of the ITB.

Numerical Analysis of Drag Reduction Characteristics of Biomimetic Puffer Skin: Effect of Spinal Height and Tilt Angle

2021 ◽  
Vol 21 (9) ◽  
pp. 4615-4624
Author(s):  
Hong-Gen Zhou ◽  
Chang-Feng Jia ◽  
Gui-Zhong Tian ◽  
Xiao-Ming Feng ◽  
Dong-Liang Fan
Keyword(s):  
Drag Reduction ◽  
Tilt Angle ◽  
Fluid Velocity ◽  
Viscous Drag ◽  
Total Drag ◽  
Pressure Drag ◽  
Reduction Efficiency ◽  
Distribution Parameters ◽  
Reduction Effect ◽  
Reduction Characteristics

Based on the migratory phenomenon of the puffer and the cone-shaped structures on its skin, the effects of spinal height and tilt angle on the drag reduction characteristics is presented by numerical simulation in this paper. The results show that the trend of total drag reduction efficiency changes from slow growth to a remarkable decline, while the viscous drag reduction efficiency changes from an obvious increase to steady growth. The total and viscous drag reduction efficiencies are 19.5% and 31.8%, respectively. In addition, with the increase in tilt angle, the total drag reduction efficiency decreases gradually; the viscous drag reduction efficiency first increases and then decreases, finally tending to be stable; and the total and viscous drag reduction efficiency reaches 20.7% and 26.7%, respectively. The flow field results indicate that the pressure drag mainly originates at the front row of the spines and that the total pressure drag can be effectively controlled by reducing the former pressure drag. With the increase in low-speed fluid and the reduction in the near-wall fluid velocity gradient, the viscous drag can be weakened. Nevertheless, the drag reduction effect is achieved only when the decrement of viscous drag is greater than the increment of pressure drag. This work can serve as a theoretical basis for optimizing the structure and distribution parameters of spines on bionic non-smooth surfaces.

Factors Affecting Car Fuel Consumption

1993 ◽  
Vol 207 (1) ◽  
pp. 1-22 ◽  
Author(s):  
M Redsell ◽  
G G Lucas ◽  
N J Ashford
Keyword(s):  
Fuel Consumption ◽  
Test Data ◽  
Regression Models ◽  
Ambient Pressure ◽  
Statistical Significance ◽  
Environmental Parameters ◽  
Independent Effect ◽  
Power Correction ◽  
Vehicle Speed ◽  
Gear Change

This paper describes a programme of statistical analyses on test data conducted to investigate the effects of a number of factors on car fuel consumption. The data used for the analyses were obtained from a comparative study of the fuel economy of petrol and diesel cars, conducted at the Department of Transport Technology, Loughborough University, on behalf of the Transport and Road Research Laboratory (TRRL). Three Vauxhall Cavalier cars (1300 cc, 1600 cc petrol and 1600 cc diesel models) and six drivers, categorized by sex and age, participated in the tests. Each test was completed over an extensive test route on public roads encompassing all types of driving environments. Factor analysis was used to determine the underlying relationships between a number of measured variables and fuel consumption. Under the ‘free-flowing’ environment of the motorway route section, fuel consumption was primarily influenced by ambient pressure, vehicle speed and frequency of gear change. In suburban conditions, only throttle velocity made any significant contribution to fuel consumption. In the tests over urban sections, the significant variables were found to be vehicle speed and deceleration, frequency of gear change and ambient pressure. Of the ambient factors examined, only pressure had any significant independent effect. The associations derived from factor analyses point the way to realistic correction techniques for vehicle test data. Regression models were constructed to fit the measured fuel consumption data to an expression derived to give fuel consumption as a function of engine, vehicle and environmental parameters. For purely urban, suburban and motorway travel and an overall journey based on a 50/40/10 per cent split of urban, suburban and motorway road types, 93.8, 92.4, 88.2 and 95 per cent of fuel consumption variance was explained by the respective regression models. Regression variables based on engine power correction factors for ambient temperature and humidity showed a degree of statistical significance in all models.

Adaptive calibration of Diesel engine injection for minimising fuel consumption with constrained NOx emissions in actual driving missions

2020 ◽  
pp. 146808742091880
Author(s):  
José Manuel Luján ◽  
Benjamín Pla ◽  
Pau Bares ◽  
Varun Pandey
Keyword(s):  
Diesel Engine ◽  
Fuel Consumption ◽  
Time Window ◽  
Transition Probability ◽  
Estimation Method ◽  
Engine Performance ◽  
Driving Cycle ◽  
Vehicle Speed ◽  
Adaptive Calibration ◽  
Emission Limits

This article proposes a method for fuel minimisation of a Diesel engine with constrained [Formula: see text] emission in actual driving mission. Specifically, the methodology involves three developments: The first is a driving cycle prediction tool which is based on the space-variant transition probability matrix obtained from an actual vehicle speed dataset. Then, a vehicle and an engine model is developed to predict the engine performance depending on the calibration for the estimated driving cycle. Finally, a controller is proposed which adapts the start-of-injection calibration map to fulfil the [Formula: see text] emission constraint while minimising the fuel consumption. The calibration is adapted during a predefined time window based on the predicted engine performance on the estimated cycle and the difference between the actual and the constraint on engine [Formula: see text] emissions. The method assessment was done experimentally in the engine test set-up. The engine performace using the method is compared with the state-of-the-art static calibration method for different [Formula: see text] emission limits on real driving cycles. The online implementation of the method shows that the fuel consumption can be reduced by 3%–4% while staying within the emission limits, indicating that the estimation method is able to capture the main driving cycle characterstics.

scholarly journals O<sub>2</sub> : CO<sub>2</sub> exchange ratio for net turbulent flux observed in an urban area of Tokyo, Japan, and its application to an evaluation of anthropogenic CO<sub>2</sub> emissions

2020 ◽  
Vol 20 (9) ◽  
pp. 5293-5308
Author(s):  
Shigeyuki Ishidoya ◽  
Hirofumi Sugawara ◽  
Yukio Terao ◽  
Naoki Kaneyasu ◽  
Nobuyuki Aoki ◽  
...  
Keyword(s):  
Fuel Consumption ◽  
Urban Area ◽  
Co2 Emission ◽  
Co2 Flux ◽  
Co2 Exchange ◽  
Co2 Fluxes ◽  
Diurnal Cycles ◽  
Co2 Concentrations ◽  
Human Respiration ◽  
Two Peaks

Abstract. In order to examine O2 consumption and CO2 emission in a megacity, continuous observations of atmospheric O2 and CO2 concentrations, along with CO2 flux, have been carried out simultaneously since March 2016 at the Yoyogi (YYG) site located in the middle of Tokyo, Japan. An average O2 : CO2 exchange ratio for net turbulent O2 and CO2 fluxes (ORF) between the urban area and the overlaying atmosphere was obtained based on an aerodynamic method using the observed O2 and CO2 concentrations. The yearly mean ORF was found to be 1.62, falling within the range of the average OR values of liquid and gas fuels, and the annual average daily mean O2 flux at YYG was estimated to be −16.3 µmol m−2 s−1 based on the ORF and CO2 flux. By using the observed ORF and CO2 flux, along with the inventory-based CO2 emission from human respiration, we estimated the average diurnal cycles of CO2 fluxes from gas and liquid fuel consumption separately for each season. Both the estimated and inventory-based CO2 fluxes from gas fuel consumption showed average diurnal cycles with two peaks, one in the morning and another one in the evening; however, the evening peak of the inventory-based gas consumption was much larger than that estimated from the CO2 flux. This can explain the discrepancy between the observed and inventory-based total CO2 fluxes at YYG. Therefore, simultaneous observations of ORF and CO2 flux are useful in validating CO2 emission inventories from statistical data.

On the Effects of Aero Boundary Layer Control on Pressure Drag Reduction in Supercavitating Bodies

2005 ◽  
Author(s):  
Yasmin Khakpour ◽  
Miad Yazdani
Keyword(s):  
Boundary Layer ◽  
Drag Reduction ◽  
Pressure Distribution ◽  
Constant Pressure ◽  
Viscous Drag ◽  
Cavity Surface ◽  
Gradient Flows ◽  
Supercavitating Vehicles ◽  
Pressure Drag ◽  
Layer Control

Supercavitation is known as the way of viscous drag reduction for the projectiles, moving in the liquid phase. In recent works, there is distinct investigation between cavitation flow and momentum transfer far away from the cavity surface. However, it seems that there is strong connection between overall flow and what takes place in the sheet cavity where a constant pressure distribution is assumed. Furthermore as we’ll see, pressure distribution on cavity surface caused due to overall conditions, induct nonaxisymetric forces and they may need to be investigated. Primarily we describe how pressure distribution into the cavity can cause separation of the aero boundary layer. Then we present some approaches by which this probable separation can be controlled. Comparisons of several conditions exhibits that at very low cavitation numbers, constant pressure assumption fails particularly for gradient shaped profiles and separation is probable if the flow is sufficiently turbulent. Air injection into the NATURALLY FORMED supercavity is found as an effective way to delay probable separation and so significant pressure drag reduction is achieved. In addition, the position of injection plays a major role to control the aero boundary layer and it has to be considered. Moreover, electromagnetic forces cause to delay or even prevent separation in high pressure gradient flows and interesting results obtained in this regard shows significant drag reduction in supercavitating vehicles.

scholarly journals Optimal and prototype dimensioning of 48V P0+P4 hybrid drivetrains

2020 ◽  
Vol 5 (3-4) ◽  
pp. 173-186
Author(s):  
Matthias Werra ◽  
Axel Sturm ◽  
Ferit Küçükay
Keyword(s):  
Fuel Consumption ◽  
Urban Areas ◽  
Combustion Engine ◽  
Electric Machine ◽  
Prototype Model ◽  
Vehicle Speed ◽  
Conventional Vehicle ◽  
Light Duty ◽  
Consumption Reduction ◽  
And Performance

Abstract This paper presents a virtual toolchain for the optimal concept and prototype dimensioning of 48 V hybrid drivetrains. First, this toolchain is used to dimension the drivetrain components for a 48 V P0+P4 hybrid which combines an electric machine in the belt drive of the internal combustion engine and a second electric machine at the rear axle. On an optimal concept level, the power and gear ratios of the electric components in the 48 V system are defined for the best fuel consumption and performance. In the second step, the optimal P0+P4 drivetrain is simulated with a prototype model using a realistic rule-based operating strategy to determine realistic behavior in legal cycles and customer operation. The optimal variant shows a fuel consumption reduction in the Worldwide harmonized Light Duty Test Cycle of 13.6 % compared to a conventional vehicle whereas the prototype simulation shows a relatively higher savings potential of 14.8 %. In the prototype simulation for customer operation, the 48 V hybrid drivetrain reduces the fuel consumption by up to 24.6 % in urban areas due to a high amount of launching and braking events. Extra-urban and highway areas show fuel reductions up to 11.6 % and 4.2 %, respectively due to higher vehicle speed and power requirements. The presented virtual toolchain can be used to combine optimal concept dimensioning with close to reality behaviour simulations to maximise realistic statements and minimize time effort.

Method for Translation of In-Use Fuel Consumption and NOX Emissions Between Different Heavy-Duty Vehicle Routes

2011 ◽  
Author(s):  
Oscar F. Delgado ◽  
Nigel N. Clark ◽  
Gregory J. Thompson
Keyword(s):  
Fuel Consumption ◽  
Relative Error ◽  
Nox Emissions ◽  
Vehicle Speed ◽  
Chassis Dynamometer ◽  
Heavy Duty ◽  
Simple Method ◽  
The Road ◽  
Heavy Duty Vehicle ◽  
Vehicle Activity

Portable emissions measurement systems (PEMS) are used to perform in-use measurements for emissions inventory and regulatory applications. PEMS data represent real world conditions more accurately than chassis dynamometer or engine dynamometer testing, arguably being the most realistic method of determining exhaust emissions over a certain driving route. However, measured emissions and fuel consumption depend strongly on both the route followed and the traffic situation that the vehicle encounters. A tool for translation of emissions and fuel consumption between diverse types of vehicle activity is required. The purpose of this paper is to assess the possibility of using route-averaged properties (kinematic parameters) for translation of fuel consumption and NOx emissions for a set of eighteen heavy-duty vehicles operating over up to eight different driving routes. A linear model developed for heavy-duty vehicle chassis dynamometer data modeling has been extended to in-use heavy-duty vehicle data. Two approaches were implemented; the first approach mimicked the prior chassis dynamometer work by incorporating average vehicle speed and average positive acceleration and the second approach incorporated road grade in a characteristic power parameter. The end result is a simple method which was shown to be accurate for estimation of fuel consumption (within 5% relative error) and NOx emissions (within 12% relative error) for over-the-road vehicles over “unseen” roads or traffic situations, without the need to perform additional over-the-road tests.

Modeling sound distribution in the bus passenger area while driving (Modelowane rozkładu dźwięku w przestrzeni pasażerskiej autobusu podczas jazdy)

2020 ◽  
Vol 128 ◽  
pp. 29-36
Author(s):  
Małgorzata Orczyk ◽  
Franciszek Tomaszewski
Keyword(s):  
Public Transport ◽  
Regression Models ◽  
Vehicle Speed ◽  
Passenger Compartment ◽  
Sound Levels ◽  
Gps Device

The article presents the results of noise tests in 18 m Solaris Urbino public transport buses. In the passenger compartment of the tested vehicles, there were ten measuring microphones and a GPS device for measuring vehicle speed. These devices recorded speed and sound levels in the tested buses. The results of the measurements were used to assess the noise in the passenger space of buses and develop regression models for each microphone location. In their algorithms, these models considered vehicle speed and sound levels. The purpose of the tests was to check if the noise in individual microphone locations depends on the cruising speed of the bus and to assess the sound distribution along with the inside space of the vehicle in motion. W artykule przedstawiono wyniki badań hałasu w autobusach komunikacji miejskiej typu Solaris Urbino 18 m. W przestrzeni pasażerskiej badanych pojazdów umieszczono 10 mikrofonów pomiarowych oraz urządzenie do pomiaru prędkości GPS, urządzenia te rejestrowały prędkość jazdy i poziomy dźwięku w badanych autobusach. Na podstawie wykonanych badań oceniono hałas w przestrzeni pasażerskiej autobusów oraz opracowano dla każdej lokalizacji mikrofonu modele regresyjne. Modele te w swoich algorytmach uwzględniały prędkość jazdy i poziomy dźwięku. Celem wykonanych badań było sprawdzenie czy hałas w poszczególnych lokalizacjach mikrofonów zależy od prędkości, z jaką jest realizowana jazda oraz zbadanie rozkładu dźwięku wzdłuż pojazdu podczas jazdy.

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