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Papers by Dan Alexandru Micu

Research paper thumbnail of Direct measurements using on-board diagnostics: study of the dynamics of a vehicle equipped with a DSG automated transmission

MATEC Web of Conferences, 2018

The paper aims to analyze a series of OBD data from a Volkswagen Passat 2.0 tdi, 103 kW, equipped... more The paper aims to analyze a series of OBD data from a Volkswagen Passat 2.0 tdi, 103 kW, equipped with an automatic DSG transmission, while traveling in the city. Some parameters are analyzed, with a special emphasis on the relation between the engine speed and vehicle speed, presenting also an example of using the information provided by the OBD to determine the gear ratios. The gear steps and the way they are used while driving the vehicle are identified in the end.

Research paper thumbnail of Analysis of the Rollover Behavior of the Bus Bodies

Analele Universităţii "Eftimie Murgu" Reşiţa: Fascicola I, Inginerie, 2011

When performing calculations using ANSYS software have been achieved so far, only a part of the r... more When performing calculations using ANSYS software have been achieved so far, only a part of the requirements imposed by regulation on how to conduct computerized mathematical modeling, the paper presented only a first set of results in this area, following research should be conducted detail.

Research paper thumbnail of Quasi-static simulation approaches on rollover impact of a bus structure

The dynamic simulations of rollover behaviour of bus bodies require more computation time than th... more The dynamic simulations of rollover behaviour of bus bodies require more computation time than the quasi-static simulations. This paper presents a study of several different virtual simulations of quasi-static loading test on body sections as an equivalent approval method of UNECE Regulation Number 66. The body section is analyzed by using the Transient Structural and Static Structural modules of Ansys. The scenarios analyze some new methods of deforming a structure by applying a force or a displacement to a plate which is in contact with a frame of the roof, or by applying different angle displacements directly to the frame. Resulting deformations are compared with a physical reference model, the absorbed energy is analyzed and a necessary mass of the structure is computed for each of the models. In some models the deformation is similar to the reference structure. Key-Words: quasi-static, rollover, bus, structure, Ansys, simulation, body section, residual space

Research paper thumbnail of Influence of Crash Box on Automotive Crashworthiness

In this paper, frontal impact behaviours of three car frontal parts with a rigid obstacle at rest... more In this paper, frontal impact behaviours of three car frontal parts with a rigid obstacle at rest is presented. The purpose is to analyze the best crashworthiness. The models have different crash boxes and are analyzed using Explicit Dynamics module of Ansys software. Shape and dimensions of the model were obtained from repeated simulations and constant improvements. Finite element mesh size for each part of the model varies, depending on its role. Velocity of the car model was computed by equalizing the kinetic energy of the modelled geometry with the kinetic energy of a considered automobile. The results present a comparison of deformations and stress, resulting an analyze of absorbed energies values during the impact. Key-Words: crash box, frontal impact, crashworthiness, Ansys, deformation, car structure

Research paper thumbnail of Compression tests methods on car engines

University of Pitesti. Scientific Bulletin - Automotive Series, Oct 30, 2017

Correct operation of the internal combustion engine requires the best possible seal of the combus... more Correct operation of the internal combustion engine requires the best possible seal of the combustion chamber during the period when the valves are closed. A perfect seal of the combustion chamber can not be achieved because of the constructional features of the segments as well as the play between the piston and the cylinder. In time, the wear of moving parts leads to a continuous worsening of the seal. Different complexity and accuracy methods are used to measure the combustion chamber's leakage. In this article, the following methods of measuring the engine cylinder leakage are presented: measuring the pressure in the cylinder at the end of the compression process using a compression gauge, measuring the current drawn by the starter motor, comparing engine speeds when the engine is cranked over by the starter and comparing engine speeds on idle. The paper presents the comparative analysis of the values obtained by different methods with the cold engine compared to the hot engine and a comparative analysis between the results obtained by using the different methods of measuring the engine cylinder leakage. The paper demonstrates that measuring the pressure using a compression gauge is the most accurate method for determining the leakage of the combustion chamber.

Research paper thumbnail of Experimental Test and Computer Simulation Research on Rollover Impact of a Bus Structure

Bus structures are tested to ensure that no element enters the survival space during an rollover ... more Bus structures are tested to ensure that no element enters the survival space during an rollover impact. In this paper an experimental of rollover test using body sections as an equivalent approval method is presented. The mass of the structure is bigger than the maximum acceptable one. Therefore, some elements of the structure enter the survival space for a little time during the impact, but in the last moments of the impact they are out of the survival space. The intrusion could be seen only using a video camera. These deformations were supposed to be obtained using a virtual simulation. Simulation results were very close to the experimental ones, but for the best fitting more parameters had to be modified. The deformation obtained using two different simulation models are compared with the experimental one. Key-Words: bus structure body sections Ansys rollover simulation

Research paper thumbnail of Comparative study on the lateral run-out of friction surfaces measurement of brake discs using a brake roller tester and a dial gauge

MATEC Web of Conferences, 2017

Brake system diagnosis is one of the most common and necessary technical operations applied to th... more Brake system diagnosis is one of the most common and necessary technical operations applied to the car, regardless of its type and operating phases. Measuring the diagnostic parameters on a roller brake tester is a fast operation with no disassembly necessary. Measuring the run-out of friction surfaces of brake discs with a dial gauge is an action that requires more extensive preparatory operations but it offers a high accuracy of the results. The paper aims to analyze the correlation between the dial gauge measured values and the diagnostic obtained using the brake roller tester.

Research paper thumbnail of Direct measurements using on-board diagnostics: study of the dynamics of a vehicle equipped with a DSG automated transmission

MATEC Web of Conferences, 2018

The paper aims to analyze a series of OBD data from a Volkswagen Passat 2.0 tdi, 103 kW, equipped... more The paper aims to analyze a series of OBD data from a Volkswagen Passat 2.0 tdi, 103 kW, equipped with an automatic DSG transmission, while traveling in the city. Some parameters are analyzed, with a special emphasis on the relation between the engine speed and vehicle speed, presenting also an example of using the information provided by the OBD to determine the gear ratios. The gear steps and the way they are used while driving the vehicle are identified in the end.

Research paper thumbnail of Analysis of the Rollover Behavior of the Bus Bodies

Analele Universităţii "Eftimie Murgu" Reşiţa: Fascicola I, Inginerie, 2011

When performing calculations using ANSYS software have been achieved so far, only a part of the r... more When performing calculations using ANSYS software have been achieved so far, only a part of the requirements imposed by regulation on how to conduct computerized mathematical modeling, the paper presented only a first set of results in this area, following research should be conducted detail.

Research paper thumbnail of Quasi-static simulation approaches on rollover impact of a bus structure

The dynamic simulations of rollover behaviour of bus bodies require more computation time than th... more The dynamic simulations of rollover behaviour of bus bodies require more computation time than the quasi-static simulations. This paper presents a study of several different virtual simulations of quasi-static loading test on body sections as an equivalent approval method of UNECE Regulation Number 66. The body section is analyzed by using the Transient Structural and Static Structural modules of Ansys. The scenarios analyze some new methods of deforming a structure by applying a force or a displacement to a plate which is in contact with a frame of the roof, or by applying different angle displacements directly to the frame. Resulting deformations are compared with a physical reference model, the absorbed energy is analyzed and a necessary mass of the structure is computed for each of the models. In some models the deformation is similar to the reference structure. Key-Words: quasi-static, rollover, bus, structure, Ansys, simulation, body section, residual space

Research paper thumbnail of Influence of Crash Box on Automotive Crashworthiness

In this paper, frontal impact behaviours of three car frontal parts with a rigid obstacle at rest... more In this paper, frontal impact behaviours of three car frontal parts with a rigid obstacle at rest is presented. The purpose is to analyze the best crashworthiness. The models have different crash boxes and are analyzed using Explicit Dynamics module of Ansys software. Shape and dimensions of the model were obtained from repeated simulations and constant improvements. Finite element mesh size for each part of the model varies, depending on its role. Velocity of the car model was computed by equalizing the kinetic energy of the modelled geometry with the kinetic energy of a considered automobile. The results present a comparison of deformations and stress, resulting an analyze of absorbed energies values during the impact. Key-Words: crash box, frontal impact, crashworthiness, Ansys, deformation, car structure

Research paper thumbnail of Compression tests methods on car engines

University of Pitesti. Scientific Bulletin - Automotive Series, Oct 30, 2017

Correct operation of the internal combustion engine requires the best possible seal of the combus... more Correct operation of the internal combustion engine requires the best possible seal of the combustion chamber during the period when the valves are closed. A perfect seal of the combustion chamber can not be achieved because of the constructional features of the segments as well as the play between the piston and the cylinder. In time, the wear of moving parts leads to a continuous worsening of the seal. Different complexity and accuracy methods are used to measure the combustion chamber's leakage. In this article, the following methods of measuring the engine cylinder leakage are presented: measuring the pressure in the cylinder at the end of the compression process using a compression gauge, measuring the current drawn by the starter motor, comparing engine speeds when the engine is cranked over by the starter and comparing engine speeds on idle. The paper presents the comparative analysis of the values obtained by different methods with the cold engine compared to the hot engine and a comparative analysis between the results obtained by using the different methods of measuring the engine cylinder leakage. The paper demonstrates that measuring the pressure using a compression gauge is the most accurate method for determining the leakage of the combustion chamber.

Research paper thumbnail of Experimental Test and Computer Simulation Research on Rollover Impact of a Bus Structure

Bus structures are tested to ensure that no element enters the survival space during an rollover ... more Bus structures are tested to ensure that no element enters the survival space during an rollover impact. In this paper an experimental of rollover test using body sections as an equivalent approval method is presented. The mass of the structure is bigger than the maximum acceptable one. Therefore, some elements of the structure enter the survival space for a little time during the impact, but in the last moments of the impact they are out of the survival space. The intrusion could be seen only using a video camera. These deformations were supposed to be obtained using a virtual simulation. Simulation results were very close to the experimental ones, but for the best fitting more parameters had to be modified. The deformation obtained using two different simulation models are compared with the experimental one. Key-Words: bus structure body sections Ansys rollover simulation

Research paper thumbnail of Comparative study on the lateral run-out of friction surfaces measurement of brake discs using a brake roller tester and a dial gauge

MATEC Web of Conferences, 2017

Brake system diagnosis is one of the most common and necessary technical operations applied to th... more Brake system diagnosis is one of the most common and necessary technical operations applied to the car, regardless of its type and operating phases. Measuring the diagnostic parameters on a roller brake tester is a fast operation with no disassembly necessary. Measuring the run-out of friction surfaces of brake discs with a dial gauge is an action that requires more extensive preparatory operations but it offers a high accuracy of the results. The paper aims to analyze the correlation between the dial gauge measured values and the diagnostic obtained using the brake roller tester.