George Dragomir

A Pneumatic Propulsion System for Urban Cars

Compressed air vehicles can be an alternative for new, low polluting emissions, urban cars. This paper presents a new innovative concept of a pneumatic motor propulsion system that aims to improve the efficiency of such systems. The advantages and the disadvantages of the proposed propulsion system are taking into consideration and some application have been analyzed.

The Calculation Algorithm for the Determination of the Temperature at the End of the Intake Stroke for GDI Engines

The paper presents an algorithm for the calculation of the parameters of the working fluid at the end of the intake stroke for a GDI engine. This is only a part of a program developed by the authors, based on an own designed cycle model. The intake process determines the further evolution of the working fluid during the entire engine cycle. The initial parameters depend on the ones at the end of the previous cycle. This algorithm calculates the temperature at the end of the intake stroke and the adiabatic exponent of the intake process.

The Calculation of the Injection Process for a SI Engine with Electromagnetic Injectors

The objective of this paper is to solve the differential equation that determines the duration of the injection and the time constant (T). Moreover, the injection rate, the instantaneous and flow section through the injector are calculated depending on the needle’s lift.

Studies Regarding Occupant Kinematics in the Vehicle at the Frontal and Rear Impact

In this paper is presented the analysis of the behavior of occupants inside a vehicle during road events, methods and means of biomechanics. Also, to analyze the behavior of the occupants were taken into account research methods impact occupant kinematics, based techniques for acquisition and processing of experimental data.

Studies about Reflected Temperature Variation for the Car Brake Disc

An exact measurement of the disc brakes car temperature present difficulties, because the higher thermal stress is produced on the shiny metallic surface, which are in movement and in sliding contact with the brake pads. If an infrared camera is used for the thermal evaluating of the disc brakes, an important factor that must be considered is the reflected temperature. The aim of this research is to study the modification of the reflected temperature in correlation with the disk brake temperature and to establish a relationship for the estimation of this variation.

THE CALCULUS OF THE FUEL CONSUMPTION AND OF THE INJECTION DURATION FOR A SPARK IGNITION ENGINE

In this paper is presented the calculus, designed by the authors, of the fuel supply scheme for a multipoint injection system. The calculated outputs are the fuel consumption and the injection duration depending on the rotational speed and on the environmental temperature. A computer program was developed to determine the parameters of a SI engine in two cases: 1. the calculation of the injection parameters depending on the rotational speed (n) and on the airfuel ratio () for environmental temperatures t0=-35...+45 C and environmental pressures p0=1·10 5 Pa; 2. the calculation of the injection parameters depending on the rotational speed (n) and on the environmental temperature t0 for a air-fuel ratio =1 and environmental pressures p0=1·10 5 Pa. Keywords— electric pump, electronic injection, flow meter, air-fuel ratio

STUDIES ABOUT EMISSIVITY VARIATION DEPENDING ON THE TEMPERATURE FOR CAR BRAKE DISC

The temperature control of automotive brake discs during operation is a difficult process because they have shiny metallic surfaces moving rotational contact with fixed brake pads and different temperature gradients. The instrument used for measuring the temperature, in this case is the thermal camera, but requires precise calibration for the emissivity of the material being analyzed and the influence of environment. The study refers to changes depending on the temperature of thermal emissivity of the material disc brake car, both in static and in dynamic regime and determining analytical relationships to estimate this variation acceptable accuracy. Keywords— brake disc, emissivity variation, reflectivity, temperature.