József Polák

57203979711

Publications - 6

Investigating the Effect of Gear Ratio in the Case of Joint Multi-Objective Optimization of Electric Motor and Gearbox

György Istenes József Polák

Publication Name: Energies

Publication Date: 2024-03-01

Volume: 17

Issue: 5

Page Range: Unknown

Description:

In this paper, a software framework is presented through an application that is able to jointly optimize an electric motor and a gearbox for the design of a drive system for electric vehicles. The framework employs a global optimization method and uses both analytical and finite element method (FEM) models to evaluate the objective functions. The optimization process is supported by a statistical surrogate model, which allows a large reduction of runtime. An earlier version of this framework was only suitable for electric motor optimization. In the application presented in a previous paper, the motor of a belt-driven electric drive system was optimized. In this paper, the optimization of the same drive system is shown, but now with a combined optimization of a gear drive and motor. The objective functions of optimization are minimizing the total loss energy and the weight of the drive system. The optimization results are compared with previous results to demonstrate the further potential of joint optimization.

Open Access: Yes

DOI: 10.3390/en17051203

The Effect of Lubricant Viscosity Variation on Tooth Friction and Hence on the Energetic Behaviour of Gear Unit

József Polák

Publication Name: Chemical Engineering Transactions

Publication Date: 2024-01-01

Volume: 114

Issue: Unknown

Page Range: 853-858

Description:

Earlier this year, I created a mathematical model of a gear unit that allowed me to investigate the energy performance of a vehicle gear unit over its full operating range. In the model created, the value of the tooth friction was determined during a precalculation and then entered into the model as a constant parameter. The problem with this approach is that it is not automated, so during the energy analysis or a possible optimisation of the gear unit, the tooth friction is always present in the model as a constant value, whereas in reality, the value of the tooth friction is different for different working points (wheel torque: Mw, wheel speed: nw) and different geometries. The viscosity of the selected lubricant has a significant influence on tooth friction, which varies partly due to temperature and partly due to load. In this paper, I will investigate the viscosity of the oil required by the gear unit at different operating points for proper operation and how this affects tooth friction and, hence, the gear unit energy loss. Since the studies showed that the effect of oil viscosity is not significant but not negligible, the determination of tooth friction can be incorporated into the gear unit model using a MATLAB function so that it is re-determined at each operating point and for each geometry change. With this modification, the estimation generated by the mathematical model describing the energetic behavior of the gear unit can be made more accurate.

Open Access: Yes

DOI: 10.3303/CET24114143

The Effect of the Ball-Track Connection on the Energy Behavior of the Roller Gearing Gearbox

József Polák

Publication Name: Acta Polytechnica Hungarica

Publication Date: 2024-01-01

Volume: 21

Issue: 4

Page Range: 185-202

Description:

In this paper, I present an energetic study of the roller gearing gearbox by investigating the friction phenomena at the ball-track contact. The novelty of the subject is that the gearbox under investigation is a Hungarian invention, the energetic investigation of which has not been dealt with before. The study was carried out using a mathematical model based on analytical principles, in the course of which the principles and models used for ball bearings and ball screw drives were adapted and applied accordingly. It is important to mention that the study does not cover the complete gearbox, so losses outside the ball-race contact, e.g. bearing friction, seal friction, oil friction, air friction, etc., have not been considered in this paper.

Open Access: Yes

DOI: 10.12700/APH.21.4.2024.4.10

Investigation of Tooth Friction Conditions of Electric Vehicle Gearbox with Plastic Gears †

József Polák

Publication Name: Engineering Proceedings

Publication Date: 2024-01-01

Volume: 79

Issue: 1

Page Range: Unknown

Description:

Earlier, I created a mathematical model of the gear unit, in which the value of the tooth friction was determined during precalculation and then entered into the model as a constant parameter. In this paper, I investigate how much viscosity oil is required at different operating points for a single-stage gear unit with plastic gears to function properly and how this affects the tooth friction and, hence, the loss of energy in the gear unit. Once the investigations are complete, the tooth friction is determined using an automated MATLAB function, which allows the tooth friction to be re-determined at each operating point. This allows for a more accurate strength dimensioning of the plastic gears in the gear unit and a more accurate model describing the gear unit’s behaviour.

Open Access: Yes

DOI: 10.3390/engproc2024079085

Theoretical Investigation of the Effect of Changes in Some Geometrical Parameters from the Point of View of the Energetic Behavior of the Roller Gearing Gearbox

József Polák

Publication Name: Chemical Engineering Transactions

Publication Date: 2023-01-01

Volume: 107

Issue: Unknown

Page Range: 379-384

Description:

In the article, the energetic analysis of the propulsion unit is presented by examining the geometrical parameters determining the friction phenomena at the ball-track connection. The novelty of the topic stems from the fact that the propulsion unit under investigation is a Hungarian invention, the energy analysis of which has not yet been dealt with in any form. To carry out the investigation, a mathematical model had to be created, which was built on the basis of analytical principles. With the help of the model, the energetic behavior of the propulsion unit can be analyzed at a theoretical level. To construct the mathematical model, the principles, research results, and models used in the case of ball bearings and ball screw drives were used, transformed, and applied in a suitable way. After the parameter tests, the analysis extended to the entire gear model, so the losses outside the ball-track connection, e.g., bearing friction, seal friction, oil friction, air friction, etc. losses, were also implemented in the mathematical model. By exploring the full efficiency field of the gearbox, it is possible to build a mathematical model that can be used to implement the propulsion unit model in an energy optimization algorithm for a given vehicle, engine-propulsion unit-vehicle combination.

Open Access: Yes

DOI: 10.3303/CET23107064

Research of vehicle parameter and sensor systems necessary to control autonomous vehicles

Dániel Pup Gábor Szakállas József Polák

Publication Name: 2018 14th IEEE ASME International Conference on Mechatronic and Embedded Systems and Applications Mesa 2018

Publication Date: 2018-08-27

Volume: Unknown

Issue: Unknown

Page Range: Unknown

Description:

Our long-term goal is to implement autonomous vehicle control functions on a standard vehicle. At first we started with the investigation of the steering, which is a crucial area of the control of autonomous vehicles. As a part of the program, vehicle dynamical measurements were carried out on a Nissan Leaf electric vehicle equipped with a sensor system.

Open Access: Yes

DOI: 10.1109/MESA.2018.8449146