Electric car does not supply all the electric energy, obtained from the electric network, to the wheels in the form of mechanical energy. During such a transformation, a part of this energy is lost. The article endeavours to determine the energy efficiency of selected electric car. The electric car used for measurements is not from the batch production since that is a vehicle designed at University of Zilina. The efficiency has been observed while driving under the conditions of amended methodology of New European Driving Cycle (NEDC). The measured value of electric car's efficiency is being analyzed from the energy consumption, as well as emission production, points of view.

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Assessing the Energy Efficiency of an Electric Car

The paper deals with the possibilities of change in adhesion force for experimental measurement on a road vehicle. The article deals with the ways in which the road vehicle can be brought to skid limit while driving at a safe speed. These are two newly designed systems (SlideWheel and Alternative SkidCar) to complement the experimental car. Both systems allow for the reduction of the adhesion force on car wheels, depending on the reduction of radial force transmitted by the car wheel. Their main difference is in the spatial arrangement and in the method of attachment to a car. The wheel units are mounted under the axles in case of SlideWheel and attached to the experimental car body via a subframe in case of Alternative SkidCar. We implemented an objective finding of their influence on the quantities describing the movement of the car in the two systems designed by the authors. Mutual comparison was made during experimental measurement during a test drive in the form of driving in a circle at a constant steering wheel turning angle. Experimental measurements were made with 50% of the radial response on car wheels. It is clear from the measured results that both systems met expectations and can be used to bring the car to the skid limit at a safe speed. Both systems help to induce any type of car skidding. The advantage of the SlideWheel system compared to Alternative SkidCar is its lower weight; the disadvantage is the size of the support wheels. The paper is focused on objective comparison of ASC and SW in terms of effect on the experimental car's behaviour.

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System for Changing the Radial Response on Car Wheels

Fuel contamination of engine lubricating oil has been previously determined to arise from two independent phenomena: the effect on oil flash point, and the effect of changing lubrication conditions on tribological pairs. This paper combines these effects and holistically analyzes the consequences of fuel in the lubricating oil of a trunk piston engine on the risk of crankcase explosion. The author hypothesized that diesel fuel as an oil contaminant increases the risk of an explosion in the crankcase of an engine due to the independent interaction of two factors: (1) changes in the oil’s combustible properties, and (2) deterioration of the lubrication conditions of the engine’s tribological nodes, such as main bearings, piston pins, or crank bearings. An experiment was performed to evaluate the rheological, ignition, and lubrication properties of two oils (SAE 30 and SAE 40) commonly used for the recirculation lubrication of marine trunk piston engines for different levels of diesel contamination. The hypothesis was partially confirmed, and the results show that contamination of the lubricating oil with diesel fuel in an amount of no more than 10% does not significantly affect the risk of explosion in the crankcase. However, diesel concentrations above 10% call for corrective action because the viscosity index, lubricity, coefficient of friction and oil film resistance change significantly. Deterioration of the tribological conditions of the engine bearings, as seen in the change in viscosity, viscosity index, and lubricity of the oil, causes an increase in bearing temperature and the possibility of hot spots leading to crankcase explosion.

https://www.mdpi.com/1996-1073/16/2/683/pdf?version=1673001110

Study of the Relationship between the Level of Lubricating Oil Contamination with Distillation Fuel and the Risk of Explosion in the Crankcase of a Marine Trunk Type Engine

The article presents the results of research on the influence of the pressure in car tires on the braking distance. Tires with lower than nominal pressure, higher than nominal pressure and for comparison with nominal pressure were analyzed. The tests were carried out on a bituminous surface typical for most road surfaces in Poland. Six tests were carried out on a dry surface, a wet surface, and a surface covered with snow. The cars were equipped with sets of summer and winter tires. The research on the influence of tire pressure on the braking distance was carried out with two practically identical cars with very similar curb weight The research on the influence of tire pressure on the braking distance was carried out with two practically identical cars with very similar curb weight. Both vehicles were equipped with an efficient ABS system. All measurement tests were performed at a speed of 50 km / h.

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Influence of tire pressure on the vehicle braking distance

During their service, engine oils suffer from various influencing parameters such as thermo-oxidative stress and nitration, hence, the accumulation of degradation products and the entry of contaminants. Accordingly, ICEs need to be able to operate satisfactorily, especially with a degraded lubricant, making it highly recommendable to use such oils for component testing in ICE development. Thus, a new nitrative thermo-oxidative ageing method is presented for closer-to-reality simulation of engine oil alteration with the intention to provide reproducibly aged oils for subsequent bench testing. With this method, a target used oil from field application was replicated and the comparability of oil condition in the lab vs. field regarding oxidation, nitration, additive depletion, and acidification amongst others was verified by conventional and advanced analyses. Special focus was laid on the identification of nitration products, proving them to be predominantly oxidized aromatic species or organophosphates. The presented method gives valuable benefit for the closer-to-reality ageing of engine oils in reasonable time frames with moderate costs and, hence, for the provision of test oils for ICE bench testing enabling rapid engine component assessment.

/pdf/implementation-of-nitration-processes-in-artificial-ageing-1ozrxk4h.pdf

Implementation of Nitration Processes in Artificial Ageing for Closer-to-Reality Simulation of Engine Oil Degradation

Internal combustion engine lubrication is essential for unwanted energy and material losses. As part of the experimental work, the lubricity of both new and worn motor oils of Society of Automotive Engineers (SAE) 15W-40 and SAE 10W-40 with different American Petroleum Institute (API) performance classifications, which were taken from various motor trains during maintenance or oil change, was assessed. A total of sixteen lubricant samples were evaluated. Lubricity, i.e., the load capacity of the lubricating film, was evaluated on the basis of the Reichert test. Viscosity, as one of the most important parameters of lubricants, was evaluated by the Stabinger Viscometer. Chemical degradation of motor oils (oxidation, nitration, sulfation), contamination of oils with fuel, soot, water, and loss of antioxidant zinc dialkyldithiophosphate (ZDDP) were monitored by Fourier-transform infrared (FTIR) spectroscopy. Of the fresh motor oils, OMV 10W-40 API SL/CF motor oil had the best lubricity. URANIA LD 15W-40 API CI-4 and M7ADS V 15W-40 API CI-4 CH-4/SL oils showed similar lubricity. M7ADS III 15W-40 API CF-4/SG motor oil showed the highest wear of wear surface, i.e., the lowest lubricity, of the tested new motor oils. Correlation analysis of the experimental data confirmed that the fuel content penetrated the motor oils significantly negatively correlates with the viscosity (R = −0.87). The low water contamination in motor oil does not cause a significant negative effect on lubricity. A significant correlation between the oxidation, nitration, and sulfation products of chemical degradation of the tested oils was confirmed (R ≥ 0.90). These degradation products improve lubricity due to their polarity, i.e., they have caused better lubricity of worn oils compared to new motor oils. Even the depletion of the antioxidant ZDDP did not affect the reduction in lubricity and anti-abrasion properties of chemically degraded motor oils. The experimental results of testing of worn motor oils taken from motor trains showed that current motor oils have excellent lubricity, which they maintain throughout their life.

Study of the Effect of Physicochemical Degradation and Contamination of Motor Oils on Their Lubricity

The paper deals with the design of a system for changing the adhesion conditions in a road vehicle. The change in adhesive force is done by changing the radial reaction which the vehicle wheel transmits to the road. The paper describes a new device (SkidSystem) and its construction. The main element of the device is done in the form of a supporting frame; four supporting wheels are attached to this frame. As a result of the mechanical change of wheel lift, the radial reaction is reduced. Subsequently, an experimental measurement is performed, where the waveforms of basic physical quantities describing the road vehicle behaviour are measured. Driving in a straight line with the so-called panic braking was selected as an experimental test. An experimental vehicle is used to carry out the experimental measurement. According to the results found, modifications of the device are proposed, so that the results were closer to testing under real conditions. Disadvantages of SlidingFrame were the increase in the car weight, a slight change in the car centre of gravity and a limited angle of inclination of the body during intensive braking.

System for Changing Adhesion Conditions in Experimental Road Vehicle

Bringing the car into a skid is realised by the adhesion force decrease. This can be reached either by a coefficient of adhesion decrease or decrease of a radial reaction on the vehicle’s wheel. For the purpose to the vehicle’s behaviour change according to stability we chose the way of radial reaction change. To decrease the adhesion force transferred by the vehicle’s wheels, the required part of radial reaction of a particular vehicle’s wheel was transferred to the road, out of the vehicle’s wheels, using additional auxiliary wheels. The auxiliary wheel units are connected to suspension arms. The article contains individual currently used ways for the adhesion force change and the unique way in the form of the system SlideWheel designed by the authors. The system SlideWheel, which was designed by the authors of this article, consists of three circuits. The first circuit is the mechanical part of the wheel unit, the second one is designed in the form of a hydraulic system and the third circuit is an electrical system used to control the wheel unit’s lift through the hydraulic system. The system was designed to be used for experimental measurement purposes in education in order to experimentally simulate oversteer or understeer of the vehicle. The real measured data from a particular drive test are stated and evaluated in the conclusion. The measurement is implemented on a special experimental vehicle equipped with the SlideWheel system. Based on the experimental measurements, we have come to the conclusion that using the SW system, it is possible to change the adhesion force of a road vehicle.The paper deals with a new system for radial reaction change of vehicle wheels. This system has minimal added weight to the vehicle. At the same time, none of the components exceeds the ground plan of the vehicle. With the newly created system, it is possible to reduce radial reactions on any car wheel. The measured results are consistent with the vehicle’s ride on sliding surfaces.

/pdf/system-allowing-adhesion-force-change-of-road-vehicle-4sdztmhjhw.pdf

System allowing adhesion force change of road vehicle

This article deals with the possibilities of adhesion force changes of a road vehicle. The authors present the possibilities of...

/pdf/modification-of-the-adhesive-force-by-changing-the-radial-1ihnlnktmx.pdf

Petr Jilek

Papers

Study of the Effect of Physicochemical Degradation and Contamination of Motor Oils on Their Lubricity

System for Changing Adhesion Conditions in Experimental Road Vehicle

System allowing adhesion force change of road vehicle

System for Changing the Radial Response on Car Wheels

Modification of the adhesive force by changing the radial reaction on vehicle wheels