Abstract: A wear and scuff-resistant plunger for use in high pressure fuel system components in internal combustion engines is provided. The plunger, which is formed of a high thermal expansion, high hardness ceramic with a thermal expansion coefficient preferably greater than 6.times.10.sup.-6 /.degree. C. and a hardness preferably greater than 800 Kg/mM.sup.2, maintains a desired optimum minimal diametral clearance while avoiding excessive fuel leakage and efficient plunger function without scuffing or sticking under the high axial, side and pressure loads and variable quality fuels encountered in the fuel system operating environment. Preferred high thermal expansion, high hardness ceramics are zirconia, alumina-zirconia and alumina.

Abstract: A wear and scuff-resistant timing plunger for a timing assembly in a unit fuel injector for an internal combustion engine is provided. The timing plunger is formed of a high thermal expansion ceramic with a thermal expansion coefficient greater than 6.times.10.sup.-6 /.degree. C. and a hardness greater than 800 Kg/mm.sup.2, which maintains a desired diametral clearance and efficient plunger function without scuffing or sticking under the axial, tangential and pressure loads encountered in the fuel injector operating environment. Preferred high thermal expansion ceramics are zirconia, alumina-zirconia and alumina.

Abstract: A low inertia, wear-resistant needle valve assembly is provided for an internal combustion engine closed nozzle unit fuel injector. The needle valve assembly includes a needle and spring retainer subassembly made from an advanced structural ceramic, such as silicon nitride. A valve seat subassembly in the injector cup is made from a combination of metal and ceramic. The assembly materials and configuration provide maximum control over the efficiency of the injection event so that the fuel injection event can be terminated quickly, thereby allowing more effective control over exhaust emissions.

Abstract: A sliding friction- and wear-resistant elephant's foot or swivel pad adjusting screw assembly for contacting an actuating member interface in an internal combustion engine is provided to transmit arcuate motion into reciprocal motion. The assembly includes a metal screw element configured to move along an arcuate path in a correspondingly configured socket in a ceramic pad element. A retainer element secures the pad element to the screw element loosely to allow this relative motion. The ceramic pad element includes a planar contact face for contacting a corresponding planar contact surface on an internal combustion engine actuating member, such as a valve, a valve crosshead or a unit fuel injector.

Abstract: A ceramic-metal composite structure which minimizes tensile ceramic loads and accommodates differences in thermal expansion characteristics between a metal member and a ceramic member without reliance on precise feature control for either member. The composite includes a mechanical retainer which allows a loose fitting relationship between the metal and ceramic members. The ceramic member is secured within a receiving bore in the metal member by the retainer in a manner which eliminates the need for precise machining of the ceramic and metal members. The metal member may be configured to accept either an internal or an external mechanical retainer element. The composite ceramic-metal structure of the present invention finds particular utility in forming a durable wear-resistant interface in internal combustion engine actuator or actuating components, such as compression brake master pistons.

Abstract: In accordance with preferred embodiments of the invention, a disc-shaped contact pad of ceramic material is disposed within a recess formed in the top surface of a metal valve crosshead. The pad is held in the recess by a retainer that clips onto the crosshead. The retainer is designed to maintain only a light pressure on only a narrow shoulder of the pad to keep it seated, and does not, itself, experience any dynamic loading. Furthermore, by the provision of a circumferential clearance between the pad and both the wall of the crosshead recess and the retainer, the need for precision machining of the ceramic material can be avoided. Additionally, a reduction of frictional sliding forces imposed on the crosshead, and in turn upon the valves, by the rocker lever is achieved by the ceramic pad, so that resultant frictional side loading is not imposed on adjacent valve components to a significant extent.

Abstract: A highly wear-resistant plunger assembly for a fuel injector, particularly an open nozzle fuel injector, is provided. The wear-resistant plunger assembly of the present invention includes components formed from wear-resistant materials specifically including, but not limited to, ceramics and metals capable of withstanding the high temperatures and frictional forces produced by prolonged motoring and other potentially adverse engine operating conditions. Different portions of the plunger assembly may be formed from different kinds of wear-resistant materials.

Abstract: A ceramic-metal composite structure which minimizes tensile ceramic loads and accommodates differences in thermal expansion characteristics between a metal member and a ceramic member without reliance on precise feature control for either member. The composite includes a mechanical retainer which allows a loose fitting relationship between the metal and ceramic members. The ceramic member is secured within a receiving bore in the metal member by the retainer in a manner which eliminates the need for precise machining of the ceramic and metal members. The metal member may be configured to accept either an internal or an external mechanical retainer element. The composite ceramic-metal structure of the present invention finds particular utility in forming a durable wear-resistant interface in internal combustion engine actuator or actuating components, such as compression brake master pistons.

Abstract: A ceramic link element suitable for use as a component in the drive train of an internal combustion engine is provided. The link includes a central shaft portion with opposed spherical terminal ends that contact correspondingly configured elements in the drive train. The ceramic link element is formed, preferably by injection molding, to be substantially free from flaws and to have maximum pore diameters, preferably a maximum pore diameter of 150 um or less on the shaft and 40 um or less on the spherical terminal ends, to produce a link with optimum mechanical strength. When these pore dimensions are met and the degree of sphericity of the spherical terminal ends is 20 um or less, the ceramic link exhibits increased mechanical strength, durability and reliability. A method of forming a ceramic link having the aforementioned characteristics is also provided.

Abstract: A ceramic-metallic interfacing joint assembly is disclosed. The joint assembly includes a pair of interfaced components in a highly loaded, sliding contact in which the contact stresses can be as high as 250,000 psi. Preferably, the pair of interfaced components includes a ball member and a complementarily shaped, mating socket member and is used in a diesel type internal combustion engine. One of the components is formed of a ceramic material having a density of at least 3.18 g/cm.sup.3 and the other component is formed of a metallic material. Preferably, the density of the ceramic material ranges from 3.18 g/cm.sup.3 to 3.25 g/cm.sup.3. This arrangement reduces the wear of the joint assembly in conjunction with the use of a lubricant which lubricates the components. Specifically, the metallic material is an iron based material while the ceramic material is a sintered silicon nitride. The ceramic material may be sintered with rare-earth metal oxides such as yttrium oxide.

Abstract: Pivot rods, such as push rods of the type found in fuel injector and engine cylinder valve drive trains, wherein a pivot element is formed of a ceramic material that is joined to a nonceramic mounting shaft as a tip portion thereof, and a method for its manufacture are improved by utilizing an attachment sleeve to interconnect the pivot element to the mounting shaft in an end-to-end abutting fashion. The attachment sleeve is secured to a portion of the pivot insert by a first interference fit securement and to an end portion of the mounting shaft by a second interference fit securement.