Cylinder Liner in Ductile Cast Iron for High Loaded Combustion Diesel Engines

Abstract

With the increase of combustion loading and the trend to reduce engine size, there is a need for thinner but stronger wet cylinder liners. While most of the current cylinder liners are made of gray cast iron, due to its good tribological behavior, machinability performance, and competitive price, alternative casting materials such as compact graphite iron, ductile iron, and even steel are being considered to address future engine demands. In this paper, a new ductile iron (DI) cast material for wet cylinder liners is presented. The material has about 60 and 70% higher limits, respectively, for tensile stress and fatigue resistance as compared to conventional gray cast irons, but without a penalty on the tribological properties. There is also a potential improvement to avoid cavitation on the outside surface due to its higher young modulus, which also equates to a higher stiffness. The tested cylinder liners were induction hardened on the running surface and a slide hone process was used to improve wear and scuffing resistance. The liners were tested in a heavy duty diesel (HDD) engine with a peak cylinder pressure (PCP) of 245 bar and showed similar wear as observed with conventional cylinder liners of gray cast iron material. The DI cylinder liners were also tested in an abusive scuffing engine test without any concern. The improved mechanical properties of the described new DI material introduce possibilities to reduce the liner wall thickness or increase specific output. The preliminary evaluation in this paper showed that this new material is feasible for HDD diesel engines with a PCP up to 250 bar. In cases where the customer needs to increase the bore diameter for output reasons there is the potential to reduce the liner wall thickness by up to 25% based on high mechanical properties (UTS, Young’s modulus and fatigue strength). In both cases, a FEA analysis to support the new component design is recommended.

Caracterización y evaluación de la templabilidad de una fundición gris empleada en la fabricación de camisas de cilindro para motores diésel

“…La capa superficial endurecida (estructura martensítica), toma lugar principalmente por la transformación de la región perlítica de la fundición gris. Las zonas ferríticas presentes antes del calentamiento, pueden también transformarse en austenita con una adecuada temperatura de austenización, para que esta última se transforme total o parcialmente en martensita (Ruiz et al, 1996;Rejowski et al, 2012). Por otra parte, la muestra que es objeto de estudio en este trabajo, posee una matriz perlítica con esteadita (eutéctico ternario de cementita, fosfuro de hierro y ferrita) y grafito laminar, con una distribución aproximada de 86,4 y 10% en peso, respectivamente, como se puede apreciar en la Fig.…”

Structural Performance of Additively Manufactured Cylinder Liner—A Numerical Study

“…Another method to control the liner deformation in the hot state is changing the liner material [12]. Materials or processes for the in-cylinder components of internal combustion engines have been investigated for better friction and performance [18,19]. The majority of the tests to study the conformability between cylinder liner and piston were carried out on cylinder liners made of cast iron [20].…”

A method of vibration damping for diesel engine cylinder liners to prevent the consequences of erosion

“…They cause erosive damage -surface degradation of the cooled part of the liner due to cavitation in the cooling liquid [3,4,5,7,16] . Erosive degradation of the surface significantly lowers durability of the cylinder [9] liner and at the same time the hourly service life of the whole engine. An effective method of preventing erosion of the surface of chilled internal combustion engines is presented in [1,4], where for protection of metal cylinder liners and block mantle it is recommended to add chilled water containing nickel salts.…”