On some Problems of Legal Regulation of the Operation of Pit Bikes on Public Roads

The paper raises the problem of normative legal reg-ulation of the operation of a new type of vehicles, such as pit bikes. The authors point out the need to improve administrative legislation related to the recognition of a pit bike as a vehicle subject to man-datory state registration. Taking into account the technical characteristics of the pit bike, the authors propose to classify this vehicle into the following categories: M – mopeds; A – motorcycles or subcat-egories A1 – motorcycles with an internal combus-tion engine displacement not exceeding 125 cubic centimeters and a maximum power not exceeding 11 kilowatts. In order to implement the basic principle of road safety, associated with the priority of the life and health of citizens, it is proposed to introduce administrative responsibility for the operation of pit bikes on public roads, including those without a special right, in a state of intoxication and by under-age citizens under the age of 16 years.

The assessment of the influence of temperature differences in individual ducts of an intake manifold on the unevenness of air filling in a cylinder of a combustion engine

The paper presents the issues related to the unevenness of air filling inside a cylinder of a combus-tion engine. In order to evaluate such an unevenness a test stand and simulation models have been built. The tests stand allows a full assessment of the influence of selected parameters on the uneven-ness of the filling process. In this case the deviations in individual ducts of an intake manifold have been analyzed. This variant has been repeated in simulation tests, where concentrated models have been used for the description of the phenomena. The tests have shown an approximately 6% influence of a 64oC temperature deviation on the unevenness of the cylinder filling. The simulation tests have not shown a significant impact of the thermal state on the filling process

The Combustion of a Liquid Fuel Droplet during Forced Convection

A new experimental technique was used to investigate single fuel droplet combustion during forced convection: the burning droplet was freely suspended in the controlled air stream, without any additional support. Based on the photo-records of the burning process, the characteristics of the change of square of droplet diameter with time were made and the actual values of burning constants were determined for four hydrocarbon fuels: ben zene, n-heptane, iso-octane and toluene. The experiments were also carried out under micro-gravity and free convection conditions for the same set of fuels. The investigations have allowed the comparison of the burning mechanism of a single droplet for the three different external conditions and have compared quantitatively the burning constants. On the basis of the color pictures of the droplet burning under forced convection conditions and the temperature and gas concentration measurements within the flame, the mechanism of combus tion of fuel droplet was explained. The physical and mathematical models of the process have been proposed which included the aerodynamics of the droplet located in the high Reynolds number air stream, the energy balance of the evaporating droplet and the chemical reaction in the flow. The models have made it possible to determine the quantitative dependence of the burning con stant of different kinds of fuels on Reynolds number, the flow field parameters and the physical and chemical parameters of the liquid and its close surround ings. The calculated values of the parameters describing the burning pro cess have been compared to the experimental data and to the results reported by other investigators. The model has revealed the importance of the feed back mechanism between physical processes involved during droplet combus tion.