  Citation: Orjuela Abril, S.; Fonseca-Vigoya, M.D.S.; García, C.P. Study of the Cylinder Deactivation on Tribological Parameters and Emissions in an Internal Combustion Engine. Lubricants 2022, 10, 60. https://doi.org/10.3390/ lubricants10040060 Received: 8 February 2022 Accepted: 1 April 2022 Published: 7 April 2022 Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affil- iations. Copyright: © 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). lubricants Article Study of the Cylinder Deactivation on Tribological Parameters and Emissions in an Internal Combustion Engine Sofia Orjuela Abril 1, *, Marlen Del Socorro Fonseca-Vigoya 1 and Carlos Pardo García 2 1 Programa de Administración de Empresas, Universidad Francisco de Paula Santander, San José de Cúcuta 540001, Colombia; marlenfonseca@ufps.edu.co 2 Programa de Ingeniería de Sistemas, Universidad Francisco de Paula Santander, San José de Cúcuta 540001, Colombia; carlospardo@ufps.edu.co * Correspondence: sofiaorjuela@ufps.edu.co; Tel.: +57-7-5-776-655 Abstract: In the present investigation, a study is carried out using numerical simulation on the effects of cylinder deactivation on tribological parameters and emissions in an internal combustion engine. For the development of the research, a tribological model was used to predict the characteristics of the lubrication film, friction conditions, blow-by gas, and deformation of the piston rings. Additionally, the construction of a CFD model was carried out to describe the kinematic movement of the engine piston. The analysis of results allowed for the demonstration of the active cylinders presenting an increase of 21.53% and 7.65% in the pressure and temperature in the cylinder wall. Additionally, the active cylinders present a reduction of 11.33% in the minimum thickness of the lubrication film and an increase in the friction force due to asperities, which implies an increase of 33% in power losses due to friction. The implementation of technologies such as cylinder deactivation causes an increase in combustion gas leaks caused by the increase in pressure of the active cylinders. However, the use of this technology allows reducing 9.09%, 8.26%, and 7.41% in CO, HC, and NO emissions. Although the use of technologies such as cylinder deactivation allows significant fuel savings, it is necessary to consider the negative effects caused by this technology, such as the increase in combustion gas leaks and the increase in power loss by the greatest frictional forces. Keywords: cylinder deactivation; power loss; piston compression ring; blow-by gas; emissions 1. Introduction Due to today’s stringent emission control regulations, manufacturers and researchers have focused efforts on minimizing fuel consumption, improving performance, and re- ducing greenhouse gas emissions caused by internal combustion engines (ICE) [1–3]. The above aims to mitigate the environmental impact and avoid the accelerated consumption of fossil fuel reserves. Research in the literature indicates that approximately 50–60% of the energy contained in fuel is lost due to thermal inefficiencies [4]. In addition, the friction between the internal components can produce losses between 4 and 20% depending on the load conditions of the engine [5,6]. Since 99.8% of the demand in the transport sector comes from hydrocarbon fueled engines, it is necessary to implement alternatives to reduce the sources of energy losses in engine components. One of the main energy-loss sources in ICEs is the interaction between the piston rings and the cylinder liner. The main objective of the compression rings is to form a hermetic seal between the cylinder liner and the piston to mitigate the leakage of combustion gases. This makes it possible to avoid pressure loss inside the combustion chamber. However, this type of sealing contributes significantly to energy losses due to frictional conditions between the piston rings and the cylinder liner. Additionally, the flexibility and thinness of the compression ring affects the sealing ability of the chamber. The above conditions lead to an increase in harmful gases from the engine [7] due to the unburned fuel trapped Lubricants 2022, 10, 60. https://doi.org/10.3390/lubricants10040060 https://www.mdpi.com/journal/lubricants