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The paper aims to present a new friction modifier (mixture of zinc and copper oleates) proper for industrial running-in of repaired engines.

The method of comparison was used for testing the offered friction modifier, a market product “Renom Engine” and a blank sample of motor oil as an etalon. Running-in time has been established. The mechanical losses change and the relevant coefficients have been determined. Data of the bearings wear have been included.

The benefit of the metal oleates and Renom Engine usage as friction modifiers has been proved. Time for industrial cold running-in of repaired engines decreases by around 20 per cent when friction modifiers are used in comparison with the etalon oil. The coefficient of the mechanical losses reduction at running-in with friction modifiers is higher than the coefficient for the etalon oil. The higher coefficient values indicate that the running-in of the working surfaces occurs more intensively and for a shorter period of time. Lower wear of the bearings is combined with smaller roughness of the friction surface, which secures higher quality of the surfaces run-in with the friction modifiers and greater capacity by around 30 per cent.

This study introduces a new friction modifier for industrial running-in of repaired engines. It would be of interest to the customers and manufacturers of oil additives.

The purpose of this paper is to determine and compare the tribological characteristics (weight wear and friction moment) of a friction couple C45/C330 at running‐in with motor oil SAE 30 and different friction modifiers of copper oleate and zinc oleate.

Friction couples are tested using the model “roller‐sector” and they are lubricated with oil SAE 30 and two other samples of SAE 30 containing 0.6 per cent copper oleate and 0.6 per cent zinc oleate, respectively. Graphic dependencies are drawn for the weight wear of the sectors, rollers and couples; as well as for the running‐in moment, the friction moments at the end of the loading and at the end of the test.

The weight wear, running‐in moment and friction moments are evaluated for friction with SAE 30 as reference and oils containing copper oleate and zinc oleate as friction modifiers. The best performing material is the oil with zinc oleate.

From a practical point of view this paper offers a new idea about a friction modifier – zinc oleate. Data for tribological characteristics and suitable concentration in the oil composition are given in the paper.

The purpose of this paper is to understand the effect of engine operating conditions and lubricant friction modifier on direct acting tappet rotation. In this research work, novel method of measuring engine tappet rotation speed has been developed. The technique is so novel. It allows the measurement on real production engine with no modification to the engine tappet bore. Also, In this paper, the effect of engine operating conditions and the effectiveness of friction modifier on tappet rotation is reported.

For the very first time, for the purpose of measuring follower rotation in a real production engine, a 4 × 6 mm2 electronic chip called Gradiometer is mounted outside the tappet housing, allowing the monitoring of tappet rotation speed without the need to machine a hole in the tappet bore. This novel technique is adopted on Mercedes Benz OM464 engine to study the effect of engine conditions and lubricant chemistry on tappet performance.

The main outcome of this research work is the development of novel method of measuring tappet rotation. Also, during the experiments, it was revealed that although friction modifiers help in reducing friction at the cam/tappet interface, they can also adversely affect the tappet rotation speed.

The novel technique developed in the research work is one of the most cost effective and simple to use. Researches can adopt the technique to study the tribological performance of direct acting tappet on real production engine. Researches acknowledge the effectiveness of friction modifiers in valve train but its effect on rotation which plays a key role in the component durability has not been the focus of most of the researches mainly due to lack of effective techniques.

Interactions of different additive types for antiwear/friction modification on surfaces can be synergistic or antagonistic in nature. This paper aims to investigate whether there are interactions between different additives in the adsorption process and whether they synergistic or antagonistic. The yielded correlations will be validated with tribological experiments to answer the question whether synergistic effects in adsorption also lead to synergistic effects in wear reduction.

In a representative study, zinc dialkyl-dithiophosphate and dithiophosphate were elaborated in combination with two different friction modifiers, a glycerol monooleate and an organic friction modifier. As base oils, mineral oil and poly alpha olefine were used. The adsorption behavior was studied via quartz crystal microbalance with dissipation using Fe₂O₃ coated quartz crystals. The tribological performance was evaluated in a ball-on-three disk tribometer. White light interferometry was used to determine the wear volume and X-ray photoelectron spectroscopy depth profiles of the tribofilms were obtained on selected systems.

The combination of dithiophosphate and an organic friction modifier (OFM) revealed a synergistic effect in terms of wear. If the initially formed films are viscoelastic, the third body formation during a tribo experiment is more pronounced and thereby wear can be reduced. As a mechanism, the adsorption of the OFM on the formed antiwear layer is proposed.

Correlating the analytical findings with performance experiments provides further understanding of the interactions between different constituents and their implications on film formation processes and wear reduction mechanisms.

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-07-2019-0293/

The purpose of this study was to investigate the use of boric acid as a friction modifier material in brake friction composites and to determine the effect of heat treatment applied during production on braking performance.

The addition of five different amounts of boric acid was balanced with cashew, which is in the friction modifier material group. The samples were produced in the following order: dry mixing, preforming and hot-pressing. The effect of the heat treatment that can be applied after the hot-pressing process on the braking performance was investigated. The tribological and physical properties of the samples were determined using tests performed according to appropriate standards. The microstructures of the friction surfaces were investigated using scanning electron microscopy.

It was observed that the tribological properties of brake friction composites containing 20% by weight of boric acid were improved. It has also been observed that the heat treatment applied after hot pressing increased the friction coefficient of the samples by 7% on average and decreased the specific wear ratio of the samples. When the surface morphologies of the samples are examined, it is seen that the friction layers of the heat-treated samples are wider, and the microvoids and cracks are reduced.

This study showed that boric acid can be used as a friction modifier in brake friction composites. It also revealed the tribological and physical contribution of the applied heat treatment to the composite. Thus, it guides brake friction composite manufacturers in the industry and researchers working in this field.

Lubricants for four‐stroke motorcycles have traditionally been rebranded versions of those used for passenger car engine lubrication. Recent developments in passenger car engine oils with the intention of improving fuel utilisation efficiencies were not compatible with some of the specific requirements of four‐stroke motorcycle powertrain lubrication. The effect of using such lubricants on the various components of the motorcycle powertrain, including the engine, clutch, gearbox, starter system drive and back torque limiter is described. The subsequent development of a new specification specifically for use in four‐stroke motorcycles is described.

This paper aims to develop of magnetic field controlled friction braking technology, a novel brake friction material with magnetic was designed and prepared in this paper.

The permalloy, a soft magnetic material, was selected as an additive to design and prepare the magnetic brake material. The friction, wear performance and permeability of each brake pads were investigated by experiments. By choosing the performance of friction coefficient fluctuation, friction coefficient deviation and mean wear rate as optimization parameters, the formulation of the magnetic friction material was optimized based on Fuzzy theory by using analytic hierarchy process methods and SPSS software.

The results showed that the developed soft magnetic friction material has not only superior friction coefficient, permeability and inferior wear rate but also good physical and mechanical properties.

Permalloy powder was added to the formulation of friction material to achieve a new functional friction material with high magnetic permeability. It is believed that this research will be of great theoretical and practical significance to develop both new brake materials and active control technology of the braking process in the future.

Today's worries and doubts related to the use of mineral oils increased because of the worldwide interest in environmental issues. This issue has increased the use of vegetable oils as an alternative lubricating oil candidate, environment‐friendly lubricant and their additives. In this study, rapeseed oil (RSO) in different concentrations, 1, 2, 3, 5, 10, 20, 30, 40, 50 (by volume percent), was added to base oil to obtain a lubricating oil candidate. Turkish originated RSO was studied as an additive candidate in this paper. The study of the effect of additives in mineral oils was carried out using a specially designed experimental system to compare lubricating oil candidates and high temperatures using engine journal bearings under statically loaded.

The purpose of this study is to investigate the influence of commercially available iron–aluminum alloy compared to copper, iron and aluminum powders on the tribological performances of friction composites. The main objective is to replace copper from the friction composite formulations.

In this study, friction composites were fabricated as of standard brake pads using commercially available iron–aluminum alloy and compared to copper powder, iron powder and aluminum powder-based without varying the other ingredients. The brake pads were developed as per the industrial procedure. The physical, mechanical and thermal properties of the developed brake pads were analyzed as per industrial standards. Tribological properties were analyzed using the chase test. Initial speed and deceleration tests in a real-time braking scenario were performed using a full-scale inertia brake dynamometer. Worn surface analysis was done using a scanning electron microscope.

The results indicate that iron–aluminum alloy (mechanomade)-based friction composites possess good physical, chemical, thermal and mechanical properties with stable fade and recovery characteristics due to its composition and flake morphology. During initial speed and deceleration braking conditions, iron–aluminum alloy also showed good tribological behavior.

This paper explains the influence of commercially available iron–aluminum alloy in friction composites in enhancing tribological performance by its composition and flake morphology, which could potentially replace copper in friction composites by solving subsequent problems.

This paper aims to discuss the influence of graphite with varying purity on the tribological performance of brake pads.

Three distinct brake pads were created within the scope of this experiment by varying the graphite purity without affecting the other components. The brake pads were made using a traditional manufacturing procedure, and industry standards were used to test the chemical, physical and mechanical properties of the newly produced brake pad. A full-scale inertia brake dynamometer was used to determine the material’s tribological characteristics. The worn surfaces of the brake pads were examined using a scanning electron microscope.

The test results indicate that brake pads containing 99% pure graphite (artificial grade) displayed good physical, chemical and mechanical features, such as consistent friction and a reduced rate of wear because of the lower impurity level, which eliminates frictional undulations.

This paper discusses the influence of graphite purity on the tribological performance of brake pads by modifying tribofilms and reducing friction undulations.