scholarly journals Investigations of the influence of engine thermal state on the fuel consumption of passenger vehicles

2017 ◽  
Vol 169 (2) ◽  
pp. 49-52
Author(s):  
Wojciech ADAMSKI ◽  
Stanisław POLAK
Keyword(s):  
Fuel Consumption ◽  
Thermal State ◽  
Climate Chamber ◽  
Warm Up ◽  
Ambient Temperatures ◽  
Passenger Vehicles ◽  
Wide Range

The paper presents the results of investigations of the fuel consumption of two vehicles performed for non-stabilized engine temperature in the start and warm up phases. The measurements were performed in a wide range of ambient temperatures from –18°C to +25°C. In order to obtain such conditions the tests were carried out in a climate chamber.

scholarly journals REDUCTION OF THE CAR ENGINE WARMING TIME WHEN USING AN ADDITIONAL HEAT SOURCE

2021 ◽  
Vol 1 (48) ◽  
pp. 117-128
Author(s):  
Gutarevych Y ◽  
◽  
Kukhtyk N ◽  
Kukhtyk V ◽  
◽  
...  
Keyword(s):  
Fuel Consumption ◽  
Heat Supply ◽  
Experimental Studies ◽  
Engine Operation ◽  
Air Filter ◽  
Warm Up ◽  
Additional Heat ◽  
Ambient Temperatures ◽  
Short Period ◽  
Air Intake

The article presents the results of additional experimental studies about the effect of heat supply to the intake air on the parameters and characteristics of the process of warming up the engine of a car. The aim of the work is to accelerate the car engine warming after starting at low temperatures. The research method is an experimental determination of the characteristics of active idling and concentrations of pollutants in the exhaust gases of the engine. The tests were performed when the car's engine was idling without heating the inlet air and with heating the inlet air through the air intake under the hood of the car and through the pipe in front of the intake manifold. Comparison of engine operation in active idling mode without heating the inlet air and with heating the air before inlet through the air intake, did not show significant differences. The long passage of preheated air through the air duct to the air filter, through the air filter and the air duct after the filter, causes cooling of the heated air and does not provide the efficiency of additional heat supply. For efficient use of additional heat supply, it is necessary to carry out this supply directly in front of the intake pipe. Most of the parameters that characterize the process of warming up the engine are obtained by direct measurement. Also, the dependences on which total indicators of economy and toxicity of the car were calculated are resulted in the article. According to the results of experimental studies, it is established that the operation of the car in low ambient temperatures leads to a deterioration of its fuel economy and environmental performance. For an internal combustion engine, with garage-free maintenance of the car in low ambient temperatures and with long periods of downtime, it is important to find and implement measures that allow, with minimal consumption of fuel and energy resources, to ensure warm-up of the cold engine. Additional heat supply to the inlet air provides rapid warming of the car engine to operating temperature, which provides a short period of preparation for the perception of the load. Intake air heating reduces fuel consumption during engine idling by an average of 4%. With additional heat supply, the concentrations of pollutants are being reduced, especially in the first 50 seconds of engine warm-up, and the total toxicity of the engine, determined by the two components (carbon monoxide and hydrocarbons) is being reduced by an average of 6%. KEY WORDS: ENGINE, HEAT, HEATING, FUEL CONSUMPTION, COOLANT TEMPERATURE, POLLUTANTS

scholarly journals Systems optimisation of an active thermal management system during engine warm-up

2012 ◽  
Vol 226 (10) ◽  
pp. 1365-1379 ◽  
Author(s):  
Richard D Burke ◽  
Andy J Lewis ◽  
Sam Akehurst ◽  
Chris J Brace ◽  
Ian Pegg ◽  
...  
Keyword(s):  
Fuel Consumption ◽  
Thermal Management ◽  
Management System ◽  
Thermal State ◽  
Exhaust Gas Recirculation ◽  
Exhaust Gas ◽  
Warm Up ◽  
Thermal Management System ◽  
Recirculation System ◽  
Gas Recirculation

Active thermal management systems offer a potential for small improvements in fuel consumption that will contribute to upcoming legislation on carbon dioxide emissions. These systems offer new degrees of freedom for engine calibration; however, their full potential will only be exploited if a systems approach to their calibration is adopted, in conjunction with other engine controls. In this work, a design-of-experiments approach is extended to allow its application to transient drive cycles performed on a dynamic test stand. Experimental precision is of crucial importance in this technique since even small errors would obscure the effects of interest. The dynamic behaviour of the engine was represented mathematically in a manner that enabled conventional steady state modelling approaches to be employed in order to predict the thermal state of critical parts of the engine as a function of the actuator settings. A 17-point test matrix was undertaken, and subsequent modelling and optimisation procedures indicated potential 2–3% fuel consumption benefits under iso-nitrogen oxide conditions. Reductions in the thermal inertia appeared to be the most effective approach for reducing the engine warm-up time, which translated approximately to a 1.3% reduction in the fuel consumption per kilogram of coolant. A novel oil-cooled exhaust gas recirculation system showed the significant benefits of cooling the exhaust gases, thereby reducing the inlet gas temperature by 5 °C and subsequently the nitrogen oxide emissions by 6%, in addition to increasing the warm-up rate of the oil. This suggested that optimising the thermal management system for cooling the gases in the exhaust gas recirculation system can offer significant improvements. For the first time this paper presents a technique that allows simple predictive models of the thermal state of the engine to be integrated into the calibration process in order to deliver the optimum benefit. In particular, it is shown how the effect of the thermal management system on the nitrogen oxides can be traded off, by advancing the injection timing, to give significant improvements in the fuel consumption.

Influence of Design of Hydraulic Components on their Operation in Low Ambient Temperatures

2011 ◽  
Vol 490 ◽  
pp. 106-118 ◽  
Author(s):  
Ryszard Jasiński
Keyword(s):  
Computer Simulation ◽  
Thermal Shock ◽  
Thermal State ◽  
Weather Conditions ◽  
Simulation Method ◽  
Large Temperature ◽  
Shock Condition ◽  
Warm Up ◽  
Ambient Temperatures ◽  
Start Up

In many machines and devices there are hydraulic drives. They should operate well in various weather conditions, also in low ambient temperatures. Some malfunctions may occur during operation of hydraulic system in a so called “thermal shock condition”, which happens when frozen hydraulic component (e.g. hydraulic pump, motor or directional spool valve) is suddenly supplied with hot oil. Transient thermal state emerges in these conditions. Particular elements of component warm up differently. This results in different thermal expansion of components during warm up, which is changing the size of clearance between cooperating elements. Experimental tests of hydraulic components in low ambient temperatures were conducted in the hydraulic laboratory of the Faculty of Mechanical Engineering of Gdansk University of Technology. They concerned: orbital motors, satellite motors, gear pumps, spool valves (also proportional), piston pumps, and hydraulic cylinders. It was proved, that in thermal shock conditions some malfunctions may occur, especially with large temperature differences between oil and component. Based on results of the tests of hydraulic components and systems start-up in low ambient temperatures, one can perform a change in components design, change the type of material of components elements, and even prepare a proper procedure to be followed during start-up of cold hydraulic components and systems. In the article discusses some designs of hydraulic components resistant to thermal shock, and how to prepare components to work in low temperatures, e.g. by providing system with an additional heater to ensure uniform heating of elements in components. Change in design of hydraulic components resistant to thermal shock conditions can be obtained through computer simulation method. Analytic and computer simulation methods can be used by engineers who design machines and devices that work in low ambient temperatures.

A Variable-Geometry Power Turbine for Marine Gas Turbines

1989 ◽  
Author(s):  
Karl W. Karstensen ◽  
Jesse O. Wiggins
Keyword(s):  
Fuel Consumption ◽  
Gas Turbines ◽  
Part Load ◽  
Surface Ship ◽  
Marine Propulsion ◽  
Medium Speed ◽  
Power Turbine ◽  
Wide Range ◽  
Electrical Generator ◽  
Variable Power

Gas turbines have been accepted in naval surface ship applications, and considerable effort has been made to improve their fuel consumption, particularly at part-load operation. This is an important parameter for shipboard engines because both propulsion and electrical-generator engines spend most of their lives operating at off-design power. An effective way to improve part-load efficiency of recuperated gas turbines is by using a variable power turbine nozzle. This paper discusses the successful use of variable power turbine nozzles in several applications in a family of engines developed for vehicular, industrial, and marine use. These engines incorporate a variable power turbine nozzle and primary surface recuperator to yield specific fuel consumption that rivals that of medium speed diesels. The paper concentrates on the experience with the variable nozzle, tracing its derivation from an existing fixed vane nozzle and its use across a wide range of engine sizes and applications. Emphasis is placed on its potential in marine propulsion and auxiliary gas turbines.

Fuel Droplet Evaporation in a Supercritical Environment

2002 ◽  
Vol 124 (4) ◽  
pp. 762-770 ◽  
Author(s):  
G. S. Zhu ◽  
S. K. Aggarwal
Keyword(s):  
Experimental Data ◽  
Phase Equilibrium ◽  
Ambient Pressure ◽  
Droplet Surface ◽  
Fuel Vapor ◽  
Phase Solubility ◽  
Liquid Density ◽  
Ambient Temperatures ◽  
Droplet Vaporization ◽  
Wide Range

This paper reports a numerical investigation of the transcritical droplet vaporization phenomena. The simulation is based on the time-dependent conservation equations for liquid and gas phases, pressure-dependent variable thermophysical properties, and a detailed treatment of liquid-vapor phase equilibrium at the droplet surface. The numerical solution of the two-phase equations employs an arbitrary Eulerian-Lagrangian, explicit-implicit method with a dynamically adaptive mesh. Three different equations of state (EOS), namely the Redlich-Kwong (RK), the Peng-Robinson (PR), and Soave-Redlich-Kwong (SRK) EOS, are employed to represent phase equilibrium at the droplet surface. In addition, two different methods are used to determine the liquid density. Results indicate that the predictions of RK-EOS are significantly different from those obtained by using the RK-EOS and SRK-EOS. For the phase-equilibrium of n-heptane-nitrogen system, the RK-EOS predicts higher liquid-phase solubility of nitrogen, higher fuel vapor concentration, lower critical-mixing-state temperature, and lower enthalpy of vaporization. As a consequence, it significantly overpredicts droplet vaporization rates, and underpredicts droplet lifetimes compared to those predicted by PR and SRK-EOS. In contrast, predictions using the PR-EOS and SRK-EOS show excellent agreement with each other and with experimental data over a wide range of conditions. A detailed investigation of the transcritical droplet vaporization phenomena indicates that at low to moderate ambient temperatures, the droplet lifetime first increases and then decreases as the ambient pressure is increased. At high ambient temperatures, however, the droplet lifetime decreases monotonically with pressure. This behavior is in accord with the reported experimental data.

scholarly journals Sesquiterpene emissions from vegetation: a review

2008 ◽  
Vol 5 (3) ◽  
pp. 761-777 ◽  
Author(s):  
T. R. Duhl ◽  
D. Helmig ◽  
A. Guenther
Keyword(s):  
Plant Species ◽  
Emission Rates ◽  
Sample Collection ◽  
Ambient Temperatures ◽  
Relative Contribution ◽  
Environmental Controls ◽  
Weather Events ◽  
Wide Range ◽  
Experimental Protocols ◽  
Selection Of Species

Abstract. This literature review summarizes the environmental controls governing biogenic sesquiterpene (SQT) emissions and presents a compendium of numerous SQT-emitting plant species as well as the quantities and ratios of SQT species they have been observed to emit. The results of many enclosure-based studies indicate that temporal SQT emission variations appear to be dominated mainly by ambient temperatures although other factors contribute (e.g., seasonal variations). This implies that SQT emissions have increased significance at certain times of the year, especially in late spring to mid-summer. The strong temperature dependency of SQT emissions also creates the distinct possibility of increasing SQT emissions in a warmer climate. Disturbances to vegetation (from herbivores and possibly violent weather events) are clearly also important in controlling short-term SQT emissions bursts, though the relative contribution of disturbance-induced emissions is not known. Based on the biogenic SQT emissions studies reviewed here, SQT emission rates among numerous species have been observed to cover a wide range of values, and exhibit substantial variability between individuals and across species, as well as at different environmental and phenological states. These emission rates span several orders of magnitude (10s–1000s of ng gDW-1 h−1). Many of the higher rates were reported by early SQT studies, which may have included artificially-elevated SQT emission rates due to higher-than-ambient enclosure temperatures and disturbances to enclosed vegetation prior to and during sample collection. When predicting landscape-level SQT fluxes, modelers must consider the numerous sources of variability driving observed SQT emissions. Characterizations of landscape and global SQT fluxes are highly uncertain given differences and uncertainties in experimental protocols and measurements, the high variability in observed emission rates from different species, the selection of species that have been studied so far, and ambiguities regarding controls over emissions. This underscores the need for standardized experimental protocols, better characterization of disturbance-induced emissions, screening of dominant plant species, and the collection of multiple replicates from several individuals within a given species or genus as well as a better understanding of seasonal dependencies of SQT emissions in order to improve the representation of SQT emission rates.

Energy intake and fur in summer- and winter-acclimated Siberian hamsters (Phodopus sungorus)

2001 ◽  
Vol 281 (2) ◽  
pp. R519-R527 ◽  
Author(s):  
Alexander S. Kauffman ◽  
Alessandra Cabrera ◽  
Irving Zucker
Keyword(s):  
Food Intake ◽  
Energy Intake ◽  
Ventral Surface ◽  
Phodopus Sungorus ◽  
Ambient Temperatures ◽  
Siberian Hamsters ◽  
Daily Food ◽  
Brown Adipose ◽  
Wide Range ◽  
The Impact

Few studies have directly addressed the impact of fur on seasonal changes in energy intake. The daily food intake of Siberian hamsters ( Phodopus sungorus) was measured under simulated summer and winter conditions in intact animals and those with varying amounts of pelage removed. Energy intake increased up to 44% above baseline control values for approximately 2–3 wk after complete shaving. Increases in food intake varied with condition and were greater in hamsters housed in short than long day lengths and at low (5°C) than moderate (23°C) ambient temperatures. Removal of 8 cm2 of dorsal fur, equivalent to 30% of the total dorsal fur surface, increased food intake, but removal of 4 cm2 had no effect. An 8-cm2 fur extirpation from the ventral surface did not increase food consumption. Food intake was not influenced differentially by fur removal from above brown adipose tissue hot spots. Fur plays a greater role in energy balance in winter- than summer-acclimated hamsters and conserves energy under a wide range of environmental conditions.

scholarly journals Real-World Measurement of Hybrid Buses’ Fuel Consumption and Pollutant Emissions in a Metropolitan Urban Road Network

Energies ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 2569 ◽  
Author(s):  
Christos Keramydas ◽  
Georgios Papadopoulos ◽  
Leonidas Ntziachristos ◽  
Ting-Shek Lo ◽  
Kwok-Lam Ng ◽  
...  
Keyword(s):  
Fuel Consumption ◽  
Road Network ◽  
Pollutant Emissions ◽  
Emission Measurement ◽  
Body Type ◽  
Urban Road Network ◽  
Urban Road ◽  
Wide Range ◽  
The Mean ◽  
Consumption Benefits

This study investigates pollutant emissions and fuel consumption of six Euro VI hybrid-diesel public transport buses operating on different scheduled routes in a metropolitan urban road network. Portable emission measurement systems (PEMS) are used in measurements and results are compared to those obtained from a paired number of Euro V conventional buses of the same body type used as control over the same routes. The selected routes vary from urban to highway driving and the experimentation was conducted over the first half of 2015. The available emissions data correspond to a wide range of driving, operating, and ambient conditions. Fuel consumption, distance- and energy-based emission levels are derived and presented in a comparative manner. The effect of different factors, including speed, ambient temperature, and road grade on fuel consumption and emissions performance is investigated. Mean fuel consumption of hybrid buses was found 6.1% lower than conventional ones, from 20% lower up to 16% higher, over six routes tested in total. The mean route difference between the two technologies was not statistically significant. Air conditioning decreased consumption benefits of the hybrid buses. Decrease of the mean route speed from 15 km h−1 tο 8 km h−1 increased the hybrid buses consumption by 63%. Nitrogen oxides (NOx) emissions of the Euro VI hybrid buses were 93 ± 5% lower than conventional Euro V ones. Nitrous oxide (N2O) emissions from hybrid Euro VI buses made up 5.9% of total greenhouse gas emissions and largely offset carbon dioxide (CO2) benefits. The results suggest that hybrid urban buses need to be assessed under realistic operation and environmental conditions to assess their true environmental and fuel consumption benefits.

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