Influence of Compression Rings on the Dynamic Characteristics and Sealing Capacity of the Combustion Chamber in Diesel Engines

Abstract

Internal combustion engines are widely implemented in several applications; however, they still face significant challenges due to the sealing capacity of the compression rings. Gas leakage through the crankcase, also known as blow-by, directly impacts power losses, overall efficiency, and global emissions. Therefore, the present study investigates the influence of parameters such as the ring gap, ring masses, and twist angle of the compression rings on the sealing capacity of the combustion chamber. A mathematical model is proposed to account for geometric, dynamic, and operational characteristics in a single-cylinder diesel engine. The results indicated that the greatest gas losses to the crankcase occur during the compression and combustion stages as a consequence of extreme pressure conditions. Specifically, at least 0.5% of the gases locked in the combustion chamber are released on each cycle, while increasing the mass of the compression rings boosts the gas leakage due to higher inertial forces in the rings. In contrast, a positive twist angle of the compression rings reduced the combustion gases leakage by . Additionally, a combined reduction in the gap of both compression rings minimized the leakage flows by 37%. In conclusion, the proposed model served as a robust tool to evaluate different parameters on the sealing capacity of the combustion chamber that contribute to minimizing global emissions. Secondary piston motion and ring distortion represent significant opportunities in future studies.

Combustion and Performance Evaluation of a Spark Ignition Engine Operating with Acetone–Butanol–Ethanol and Hydroxy

“…Accordingly, Figure 11 summarizes the fuel energy allocation based on the power output and exhaust gases directly measured on the experimental assessment. Notice that the energy loss comprises lubrication oil, refrigerant, among other energy losses such as blow-by gas that limit energy conversion [34]. According to the results, increasing the engine load intensifies the energy contribution of both the power output and exhaust gases.…”

“…As previously discussed, the blow-by gas losses phenomena account for a significant share of energy losses. Therefore, incorporating such effects in the thermodynamic model becomes a determinant factor in predicting the operating conditions [34]. Hence, the study implements the formulation introduced by Irimescu [35] to predict the energy losses derived from exhaust gas leakage inside the combustion chamber as described in Equations ( 12) and (13).…”

Experimental evaluation of low-displacement compression ignited engines operating with hydroxy gas as a supplementary gaseous fuel

“…Nowadays, severe regulations have been set by governmental and international entities since these substances alter the balance and the natural composition of air, which represents an imminent risk for human health [ 5 ]. Moreover, exhaust gases emanate non-toxic gases such as CO 2 , which accumulate in the atmosphere creating a greenhouse effect that directly contributes to global warming [ 6 ]. According to the International Energy Agency (IEA), the energy sector will increase CO 2 emissions by 50% in 2030 [ 7 ].…”

Analysis of the Influence of Textured Surfaces and Lubrication Conditions on the Tribological Performance between the Compression Ring and Cylinder Liner

“…In general, investigations focused on experimentation are difficult to carry out due to the high intrusion that must be carried out in the thermal machines for the measurement process under operating conditions [16][17][18]. Therefore, in recent years, the development of research based on analytical models has been chosen, which has allowed a deeper compression of the tribological behavior between the union of the cylinder liner and the piston rings [19,20]. Studies of this type include the research by Baker et al [21], who studied the elastodynamics of piston rings and their effect on combustion gas leakage.…”