scholarly journals Under Pressure—Users’ Perception of Range Stress in the Context of Charging and Traditional Refueling

2019 ◽  
Vol 10 (3) ◽  
pp. 50 ◽  
Author(s):  
Ralf Philipsen ◽  
Teresa Brell ◽  
Hannah Biermann ◽  
Martina Ziefle
Keyword(s):  
Risk Taking ◽  
Internal Combustion Engines ◽  
Combustion Engines ◽  
Charging Infrastructure ◽  
Electric Drives ◽  
Experience Levels ◽  
Important Barrier ◽  
The One ◽  
Technology Commitment ◽  
Privately Owned

Although electric drives can locally reduce the environmental impact of traffic, the penetration rates of battery electric vehicles (BEV) are far below expectations, not least because the charging infrastructure network is still considered insufficient by potential users. Therefore, the planning of charging infrastructure that considers both needs and user requirements is essential to remove an important barrier to widespread adaptation of e-vehicles, but it is also a challenge. A better understanding of the charging behavior and the underlying usage motivation is therefore needed. A frequently mentioned factor is the so-called range stress. While there are many studies on this subject with new BEV users, there is a lack of approaches that also include experienced e-vehicle users and at the same time allow a comparison with drivers of cars with internal combustion engines (ICE). In this paper, this is realized with the help of a questionnaire study ( n = 204 ). The results show that ICE and BEV users at different experience levels hardly differ regarding the perceived range stress; BEV users even perceive less stress. BEV users also showed more trust in the vehicle and in the tank/battery indicators, while this trust depends only marginally on the type of information provided by the car. Furthermore, there is a correlation between users’ technology commitment and risk-taking, on the one hand, and range stress, on the other. However, for the prediction of range stress, gender, experience with e-cars, and the question of whether cars are privately owned, or car-sharing is used, are more relevant.

scholarly journals Geometry of shape of profiles of the sliding surface of ring seals in the aspect of friction losses and oil film parameters

2016 ◽  
Vol 167 (4) ◽  
pp. 38-52 ◽  
Author(s):  
Piotr WRÓBLEWSKI ◽  
Antoni ISKRA
Keyword(s):  
Internal Combustion Engines ◽  
Surface Profile ◽  
Combustion Engines ◽  
Sliding Surface ◽  
Oil Consumption ◽  
Oil Film ◽  
Close Relationship ◽  
Ring Seal ◽  
The One ◽  
The Impact

The article describes the results of simulations of the approved variations of sliding surfaces of ring seals in relation to a reference symmetrical barrel profile which is most often used in piston internal combustion engines. In particular the paper discusses the impact of the five assumed variants of sliding profiles of ring seals onto the thickness of oil film left on the cylinder face by a bottom and upper ring seal, the distribution of internal friction force in oil film between the ring seal set and the cylinder face, finally the oil film cover on a sliding surface of the upper ring seal. The results presented in the article show a close relationship between the sliding surface profile of ring seals and a unit oil consumption. A relationship between these parameters for the elements lying in the movement plane of a wrist pin axis was proven, as well as for the one lying in the plane perpendicular to it. Exemplary parameters of oil film and friction losses were presented while assuming a constant total axial values of the height and depth of circumferential grooves. The shapes of these grooves on the sliding surface of the ring seals in free state can be made with electroerosion microprocessing or ablative laser microprocessing.

scholarly journals Application Isssues of the Semi-Markov Reliability Model

2015 ◽  
Vol 22 (1) ◽  
pp. 55-64 ◽  
Author(s):  
Jacek Rudnicki
Keyword(s):  
Internal Combustion Engines ◽  
Combustion Engines ◽  
Mechanical Device ◽  
The Past ◽  
Engine Piston ◽  
Complex Process ◽  
State Changes ◽  
The One ◽  
Infinite Set ◽  
Random Nature

Abstract Predicting the reliability of marine internal combustion engines, for instance, is of particular importance, as it makes it possible to predict their future reliability states based on the information on the past states. Correct reliability prediction is a complex process which consists in processing empirical results obtained from operating practice, complemented by analytical considerations. The process of technical state changes of each mechanical device is stochastic and continuous in states and time, hence the need to divide this infinite set of engine states into a finite number of subsets (classes), which can be clearly and permanently identified using the existing diagnosing system. Using the engine piston-crankshaft system as an example, the article presents a proposal for a mathematical model of reliability which, on the one hand, takes into account random nature of phenomena leading to the damage, and at the same time reveals certain application flexibility and the resultant practical usability.

scholarly journals The influence of pressure on the spontaneous ignition of inflammable gas-air mixtures. II.—Pentane-air mixtures

1933 ◽  
Vol 143 (848) ◽  
pp. 168-176 ◽  
Keyword(s):  
Atmospheric Pressure ◽  
Internal Combustion Engines ◽  
Critical Pressure ◽  
Initial Pressure ◽  
Spontaneous Ignition ◽  
Combustion Engines ◽  
Compression Method ◽  
Ignition Point ◽  
Hydrocarbon Combustion ◽  
The One

In a recent communication an account was given of an investigation into the influence of varying initial pressure on the spontaneous ignition of butane-air mixtures. Whereas at atmospheric pressure the known values of ignition temperatures for these mixtures were between circa 550 and 600°C. at higher pressures as, for example, those employed in the adiabatic compression method they had been located at circa 300°C. By progressively increasing the pressure from atmospheric to 15 atmospheres we were able to show that the ignition points actually fell into two well-defined groups the one above 450° C. for pressures not exceeding about 3 atmospheres and the other below 370°C. for higher pressures. Transference of an ignition point from the higher to the lower group occurred at a definite critical pressure which depended upon the composition of the mixture. This new features of hydrocarbon combustion seemed of undoubted importance in regard to the phenomenon of "knock" in internal combustion engines, the more so when it was discovered that the presence of 0·05% of lead tetraethyl was capable at pressure near the critical transition pressure of raising the ignition point from the lower to the higher group. On this account we have been determining the critical pressure regions in other explosive media and our results for pentane-air mixtures are incorporated in this paper.

Thermodynamics of indirect water injection in internal combustion engines: Analysis of the fresh mixture cooling effect

2018 ◽  
Vol 20 (5) ◽  
pp. 527-539 ◽  
Author(s):  
Alexandre Vaudrey
Keyword(s):  
Internal Combustion Engines ◽  
Water Injection ◽  
Internal Combustion ◽  
Intake Manifold ◽  
Combustion Engines ◽  
Fresh Mixture ◽  
Mixture Density ◽  
Set Up ◽  
The One ◽  
Air Conditioning Systems

Water injection is a well-known efficient way to improve the performance of internal combustion engines. Amazingly, most of previous studies have yet only assess this process in an experimental manner, depriving us of an understanding of its specific influence on different operating phases of the engine – density of the aspirated fresh mixture, work required by the compression stroke, and so on – but also of the possibility to predict its effects if set up on an existing engine. Thanks to a theoretical framework specifically developed, and similar to the one commonly used for the analysis of air conditioning systems, we start in this article to untangle in a theoretical manner the different consequences of water injection on internal combustion engines. This first study is specifically focused on the fresh mixture density increase, due to the vaporisation of liquid water in the intake manifold. Results show that in the best scenarios, we cannot expect to increase the amount of fuel finally aspirated into the cylinders by more than 10%. The methodology presented here can be of a precious help for the optimisation of such process if applied to existing or future engines.

scholarly journals Thermodynamics of indirect water injection in internal combustion engines: theoretical assessment of the fresh mixture cooling effect

2017 ◽  
Author(s):  
Alexandre Vaudrey
Keyword(s):  
Internal Combustion Engines ◽  
Water Injection ◽  
Internal Combustion ◽  
Intake Manifold ◽  
Combustion Engines ◽  
Fresh Mixture ◽  
Mixture Density ◽  
Set Up ◽  
The One ◽  
Air Conditioning Systems

Water injection is a well-known efficient way to improve the performance of internal combustion engines. Amazingly, most of previous studies have yet only assess this process in an experimental manner, depriving us of an understanding of its specific influence on different operating phases of the engine (density of the aspirated fresh mixture, work required by the compression stroke, and so on) but also of the possibility to predict its effects if set up on an existing engine. Thanks to a theoretical framework specifically developed, and similar to the one commonly used for the analysis of air conditioning systems, we start in this paper to untangle in a theoretical manner the different consequences of water injection on internal combustion engines.This first study is specifically focused on the fresh mixture density increase, due to the vaporisation of liquid water in the intake manifold. Results show that, in the best scenarios, we cannot expect to increase the amount of fuel finally aspirated into the cylinders by more than 10%. The methodology presented here, as well as the python software specifically developed, can be of a precious help for the optimisation of such process if applied to existing or future engines.

scholarly journals The development of electromobility - in the aspect of the operation of cars with electric drive

2018 ◽  
Vol 19 (12) ◽  
pp. 126-128
Author(s):  
Zbigniew Łosiewicz ◽  
Ewelina Sendek-Matysiak
Keyword(s):  
Electric Drive ◽  
Internal Combustion Engines ◽  
Transition Period ◽  
Internal Combustion ◽  
Combustion Engines ◽  
Battery Charging ◽  
Electric Cars ◽  
Electric Drives ◽  
Charging Station

The article discusses problems related to the operation of electric cars. Currently, there is a transition period between the use of internal combustion engines and purely electric drives. The biggest problem is the storage of electricity and access to the battery charging station.

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