Decreasing production and rising prices of cars, especially those with electric drive, lead to longer use of cars with internal combustion engines. It can be assumed that in the future, more and more cars powered by such engines with high mileage and therefore high wear will be used. Engine wear leads to reduced efficiency and increased emissions. This paper analyzes the impact of wear of the piston–rings–cylinder system components on energy losses associated with gas leakage from the combustion chamber and friction of the rings against the cylinder liner in a car spark-ignition engine. A ring pack model was used for the analyses. The input data for the simulation were gained in measurements made on the engine test stand and measurements of the wear of the engine components used in the car. The energy losses associated with blow-by in an unworn engine ranged from 1.5% of the indicated work at high load to almost 5% at low load. In the engine after 300,000 km, these losses increased to 2.5% and 7.5%, respectively. Ring friction losses in an unworn engine ranged from 1.5% at high load to 9% at low load. The effect of wear on these losses was smaller. They increased by only 0.1% at high load and 1% at low load.

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Energy Losses Related to Ring Pack Wear in Gasoline Car Engine

Prognostic and health management (PHM) methods focus on improving the performance and reliability of systems with a high degree of complexity and criticality. These systems include engines, turbines, and robotic systems. PHM methods involve managing technical processes, such as condition monitoring, fault diagnosis, health prognosis, and maintenance decision-making. Various software and applications deal with the processes mentioned above independently. We can also observe different development levels, making connecting all of the machine’s technical processes in one health management system with the best possible output a challenging task. This study’s objective was to outline the scope of PHM methods in real-time conditions and propose new directions to develop a decision support tool for marine diesel engines. In this paper, we illustrate PHM processes and the state of the art in the marine industry for each technical process. Then, we review PHM methods and limitations for marine diesel engines. Finally, we analyze future research opportunities for the marine industry and their role in developing systems’ performance and reliability. The main added value of the research is that a research gap was found in this research field, which is that new advanced PHM methods have to be implemented for marine diesel engines. Our suggestions to improve marine diesel engines’ operation and maintenance include implementing advanced PHM methods and utilizing predictive analytics and machine learning.

A Review of Prognostic and Health Management (PHM) Methods and Limitations for Marine Diesel Engines: New Research Directions

Engines with homogenous charge compression ignition (HCCI) are the low-temperature combustion models in which automatic oxidation reactions occur with the effect of in-cylinder pressure and heat at the end of preparation of homogenous air-fuel mixture and compression stroke within the cylinder by means of port injection or early direct injection. In-cylinder gas temperatures of such engines during the cycle are lower than conventional internal combustion engines. Therefore, they cause zero NOx and soot emissions. Moreover, the occurrence of combustion in very small crankshaft angles results in a decrease in heat losses observed in cylinder walls and an increase in thermal efficiency. Reducing mechanical friction is highly significant for increasing the effective productivity of HCCI engines. In internal combustion engines, 10% of total energy obtained from the fuel is spent on the heat emerging due to mechanical frictions. 20% of mechanical friction results from the friction occurring between piston ring and liners. In this article, frictional characteristics of compression ring (TOP) and piston skirt area have been examined for two different engine speeds and lubricants, by using technical properties of single-cylinder HCCI engine and in-cylinder pressure and temperature data obtained under full load by means of GT-SUITE software. As the increase in pressure, occurring inside the cylinder at the end of the exhaust stroke and at the beginning of intake stroke, increases ring pressure load in HCCI engines, higher level of piston ring frictions has been observed when compared to internal combustion engines with the same technical properties. Piston ring contact pressure force is a more effective parameter in terms of piston frictions, when compared to hydrodynamic pressure force. The use of lubricants with higher viscosity (SAE 10W-40) has enabled the piston to move more laterally. According to the analysis results, a maximum piston speed of 3.92 m/s for 800 rpm engine speed and 7.85 m/s for 1600 rpm engine speed has been obtained. Maximum friction power losses have been found as 63.84 W at 800 rpm engine speed and 85.91 W at 1600 rpm engine speed. Oil film thickness has obtained in the middle of the piston stroke in the intake, compression, power and exhaust strokes, respectively, 1.809, 1.674, 1.547 and 1.792 µm at 800 rpm engine speed and 1.101, 1.018, 0.932 and 1.119 µm at 1600 rpm engine speed.

Analysis of the effects of lubricating oil viscosity and engine speed on piston-cylinder liner frictions in a single cylinder HCCI engine by GT-SUITE program

Haluk Gunes

Papers

Analysis of the effects of lubricating oil viscosity and engine speed on piston-cylinder liner frictions in a single cylinder HCCI engine by GT-SUITE program