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Radial slide bearings are typically used in turbochargers (among other applications), owing to their simple design and advantages, such as good heat dissipation from the working zone, high stability of operation and low resistance to motion. The current research is both experimental and theoretical. In a state of static equilibrium, the operation of a bearing can be described using a system of five coupled differential equations. The bearing’s operating parameters are related to the type of oil used. Two types of oil, VG46 and VG68, were used for testing. In accordance with the applicable standard, the tolerance of kinematic viscosity of oils is ±10%. The results imply a significant influence of the oil class and viscosity tolerance on the resistance to motion caused by internal friction forces in the oil. In conclusion, it seems advisable that the calculation procedures currently in use should include the slide bearing design optimisation by taking the resistance to motion in the bearing into account.

Natural gas is one of the potential combustion engine fuels whose proportion in the overall energy balance is expected to increase. Owing to some of its properties, its use requires a dual-fuel supply system; thus, the use of natural gas as a fuel for diesel engines is currently limited. Systems that supply gas fuel to diesel engines do not usually interfere with the engine control system. This solution significantly reduces system-installation costs. However, as demonstrated in the present study, it considerably changes the course of the combustion process, which increases thermal and mechanical loads. In this case, the combustion process can be controlled by changing the liquid fuel injection pressure or advancing the injection angle. This, however, requires interference with the engine control system.

In the present work, biofuels produced from different raw fatty materials have been proposed asa dominant fuel component in biodiesel–diesel fuel blends. Biofuels were produced from pork lard and rapeseed oil by alkali transesterification usingmethyl alcohol. Blends of biofuels in volumetric proportions of 60 and 80% of the biocomponent and the remaining part of the conventional fuel were used in a compression ignition engine designed for medium-duty vehicles. The experiments were conducted attwo engine rotational speeds (1500 and 3000 rpm,respectively) and a set of load conditions (50, 100, and200 Nm,respectively). The tests focused onengine efficiency parameters (brake-specific fuel consumption and brake fuel conversion efficiency) as well as exhaust gas emissions (hydrocarbons, carbon monoxide, and carbon dioxide were determined). The obtained results indicate that blends containing biocomponents produced from pork lard were characterized by superior fuel consumption and efficiency results, compared to blends containing biocomponents produced from rapeseed oil. In terms of exhaust emissions,biocomponents produced from pork lard were also characterized by lower emission of all of the examined components compared to rapeseed methyl ester–diesel blends. This study proposes that fuel components obtained from custom (animal) raw-fatty material canbe an effective substitute for commonly used rapeseed oil methyl esters.

The article provides and discusses results of tests of a bypass-controlled hydraulic shock absorber studied at a test stand(mechanical inductor),making it possible to plot work charts and determine velocity characteristics. Measurements of the shock absorber performance were conducted at different values of velocity and forced travel. The measurements were carried out for two statuses, i.e. for the emergency power failure condition and for normal setting. The results thus obtained can be used in simulation tests as input shock absorption characteristics for different technical conditions.

This article presents results of tests of the effect exerted by technical condition of shock absorbers on the braking efficiency of an automotive vehicle. The tests were conducted using Fiat Seicento featuring front shock absorbers which enabled shock-absorbing fluid-level adjustment. The tests comprised measurements conducted on the shock absorbers in four states, i.e. the nominal state with the fluid level at 100%, with shock-absorbing fluid levels of 25%, 50% and 75% as well as with the fluid tank completely empty (0%). Road tests of braking efficiency were conducted on cobbled pavement by means of a decelerometer.

The article presented the results of vibration measurements of selected elements of the vehicle during the test vibration carried out on a bench with a harmonic kinematic extortion. The results of research carried out for the car when replacing tire and wheels steel tripod eliminating the influence of elasticity and damping tires. The tests were performed at various values of the shock absorber fluid filling (from 100% to 50% of the shock absorber fluid). For registered vibration acceleration STFT analysis was performed.

The paper presents the design solutions and fastening mounting frames in special vehicles. Special Vehicles is an interesting and growing market in the production of heavy vehicles. Due to the nature of the use of these vehicles of their design solutions require constant change and adaptation, which opens up the possibility of a utilitarian research

The article presented part of the guidelines used for the modification of special purpose vehicle bodies. For example brand vehicles are details about the possibility of limiting the extension of the vehicle overhang, weight distribution, etc., and construction methods used in practice when extending the overhang of the vehicle. Describes the applicable rules for different technologies, ie. riveting, bolting, welding used in the modification of the frame.

The article presents the methodology of Common Rail injector diagnostic, regeneration and regulation with use of professional test stands. The EPS 815 machine can be used to test and repair all BOSCH injectors fully satisfying the producer requirements and standards. The article describes an example injector diagnosis with use of such test stand and additionally presents appropriate injector regeneration and encoding techniques

The article presents a statistical analysis of car repair data gathered by an examined company over five-year time interval. It is based on a SQL database which contains information about all realized orders. The analysis defines the structure of the set of repaired car makes and additionally to find the most frequent vehicle defects.

Vibration phenomena occurring in vehicles are very relevant for safety and comfort. Passenger car must be considered as a multi-technical system in which there are non-linear phenomena. Therefore, vibrations occurring in vehicles should be analyzed in many points of car structure and relate them to other criteria analysis. The paper presents examples of the results of vibration and their distribution at selected points during laboratory research and road tests.

The results of the examination of a vehicle suspension system in the plate position are presented in the paper. The model vehicle is a Fiat Seicento with front independent suspension, McPherson type, with the steering system and with the semi-trailing arm in the rear suspension. Identification of the model was made by comparing the simulation results with the results from the test stand. A multibody model of the vehicle will be used in studies of the impact of shock absorber technical conditions on the dynamics of automotive vehicles.

This paper presents results of the modern vehicle shock absorbers’ researches on indicator test stand. On this stand can be determined the diagrams of force versus displacement and force versus velocity. These diagrams can be determined for changeable strokes and constant velocities or the opposite way round. In researches the modern hydraulic twin-tube vehicle shock absorber was modificated and the changes of oil volume were possible. There was determined the influence of oil volume changes on force versus displacement and force versus velocity diagrams. On the basis of force versus velocity diagrams, the dumping characteristics were determined (value of force for maximum velocity on this diagram). The influence of oil volume changes on dumping characteristics was determined too. The results of this investigation can be used in simulation researches of vehicle suspension dynamic.

The paper presents results of vibro-acoustic signal analysis (acceleration of the unsprung mass of passenger’s car suspension actuated to vibration by harmonic, kinematic vibration). The range of research has included front shock absorber for Fiat Seicento with simulated fault (oil leak). Force process consisted of three phases: increase of frequency, vibration with constant frequency (above 21 Hz) and decreases of frequency.For the analysis process Short Time Fourier Transform method was used with superposition of rectangles window and with zero complement method. On STFT spectrum resonance frequency of unsprung mass was identified. The estimator was the means of maximum acceleration amplitude peak in frequency band round resonance frequency. The result of investigation was presented on diagrams with changeable value of estimator for different technical conditions of shock absorber (with different volume of oil inside the shock absorber)

This paper presents results of simulation researches of changes in technical condition of vehicle hydropneumatic suspension (changes of pressure nitrogen in hydropneumatic sphere which causes changes in gas spring and dumper characteristics). The static load of vehicle has been changed too. The input harmonic signal was used and changes of magnitude for higher range harmonics were analyzed.