Wyniki wyszukiwania - BazTech

1

Calculation of the optimal braking force distribution in three-axle trailers with tandem suspension

Kamiński Zbigniew

Acta Mechanica et Automatica

|

2022

|

Vol. 16, no. 3

189--199

EN

Heavy agricultural trailers can be equipped with a three-axle chassis with a tandem axle set at the rear and one mounted on a turntable at the front. In such trailers, selection of the distribution of braking forces that meet the requirements of the EU Directive 2015/68, with regard to braking, largely depends on the type of tandem suspension used. The requirements for brake force distribution in agricultural trailers of categories R3 and R4 are described. On this basis, a methodology for calculating the optimal linear distribution of braking forces, characteristic of agricultural trailers with air braking systems, was developed. An analysis of the forces acting on a 24-tonne three-axle trailer during braking was performed for five different suspensions of the rear tandem axle. An optimization algo-rithm using the quasi Monte Carlo method was described, on the basis of which a computer program for selection of the linear distribution of braking forces was developed. The calculations were made for an empty and loaded trailer with and without the weight of the tandem suspension. The most uniform distribution of braking forces was obtained for two leaf spring with dynamic equalization and air suspension, in which the ratio of the braking force of the tandem axle and the total braking force varied between 22.9% and 25.5% for the different calculation variants. A large variation in the braking force distribution was achieved for the two leaf spring suspension, in which the ratio of tandem axle braking force and the total braking force ranged from 2.7% to 6.4% for the leading axle and from 27.8% to 36.2% for the trailing axle. The presented calculation methodology can be used in the initial phase of the design of air braking systems for three-axle agricultural trailers.

2

Measurement and evaluation of functional and operational coefficients of hydraulic solenoid valve prototypes used for variable valve timing control in combustion engines

Kalinowski Marcin, Kamiński Zbigniew

Acta Mechanica et Automatica

|

2021

|

Vol. 15, no. 2

74--81

EN

: This paper describes the engineering structure and functions of a typical solenoid valve used in hydraulic mechanisms that are based on variable camshaft timing (VCT). The main operating parameters and functional utility coefficients of hydraulic solenoid valves have been defined. Tests of 10 reference and 10 prototype valves were run on a test stand for a comparative assessment of both engineering concepts based on Welch and Mann–Whitney statistical tests of the mean values of designated coefficients. The studies identified differences between both designs, and the obtained research material was used as an input to improve the performance of the engineered concept. To perform a final evaluation of the effects that arise as a result of changes introduced to some functional–operational coefficients, additional tests are required to be run on an engine testbed. The applied test methodology may then be used for control and verification tests of the valves, which can further be used in VCT technology.

3

Calculations of the optimal distribution of brake force in agricultural vehicles categories R3 and R4

Kamiński Zbigniew, Radzajewski Paweł

Eksploatacja i Niezawodność

|

2019

|

Vol. 21, no. 4

645--653

EN

Fulfilling the requirements of the EU Directive 2015/68 in the area of braking for agricultural trailers depends on the proper selection of individual components of the braking system. This paper describes the requirements regarding braking performance and distribution of brake forces in agricultural trailers in R3 and R4 categories. On this basis, a methodology for calculating the optimal linear distribution of brake forces, characteristic for agricultural trailers with pneumatic braking systems, has been developed. The examples of calculation of an optimal distribution of brake forces for a two- and three-axle trailer with a tandem suspension system of the rear axle assembly have been provided. The optimization algorithm with the Monte Carlo method has been described, based on which a computer program was developed to select a linear distribution of brake forces in a three-axle trailer with ‘walking beam’ and ‘bogie’ suspensions. The presented calculations can be used in the design process to select the parameters of wheel braking mechanisms and then the characteristics of the pneumatic valves of the braking system.

PL

Spełnienie wymagań Dyrektywy UE 2015/68 w zakresie hamowania przyczep rolniczych zależy od właściwego doboru poszczególnych komponentów układu hamulcowego. W pracy opisano wymagania dotyczące skuteczności hamowania oraz rozdziału sił hamujących w przyczepach rolniczych kategorii R3 i R4. Na tej podstawie opracowano metodykę obliczeń optymalnego liniowego rozdziału sił hamujących, charakterystycznego dla przyczep rolniczych z pneumatycznymi układami hamulcowymi. Zamieszczono przykłady obliczeń optymalnego rozdziału sił hamujących dla przyczepy dwu i trzyosiowej z tandemowym układem zawieszenia zespołu osi tylnych. Opisano algorytm optymalizacji metodą Monte Carlo, na podstawie którego opracowano program komputerowy do doboru liniowego rozdziału sił hamujących w przyczepie trzyosiowej z zawieszeniem „walking beam” i „bogie”. Przedstawione obliczenia można wykorzystać w procesie projektowania do doboru parametrów kołowych mechanizmów hamulcowych, a następnie charakterystyk zaworów pneumatycznych układu hamulcowego.

4

Methods for improving the dynamic properties of the air braking systems of low-speed agricultural trailers

Kulikowski Krzysztof, Kamiński Zbigniew

Archiwum Motoryzacji

|

2019

|

Vol. 84, nr 2

5--22

EN

Too low an operating speed of trailer air braking systems may lead to an inhibition of the braking asynchrony of agricultural tractor trailer units. Improved braking dynamics advanced braking systems with an electronic control unit (e.g. Trailer EBS) provide a more rational solution for high speed agricultural vehicles. In this paper, an overview of other methods for developing the dynamic properties of air braking systems for agricultural trailers is described. This paper provides an examples of braking system design parameters optimization, using a variety of accelerating valves and dynamic properties correcting devises, also as well, by using simple systems with an electronic controllers. The described methods of dynamic properties improvements can be used to improve the speed and operation synchrony of the air braking systems of low-speed agricultural trailers. The paper presents the influence of some of the described methods, with different levels of complexity, on the properties of typical air braking systems.