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A laboratory method has been developed to rank the scuff resistance of piston ring coatings. This method employs a standard wear test apparatus with a specially designed sample holder. Scuff resistance of electrolytic chrome, thermal spray and physical vapor deposition (PVD) face coatings have been examined. Based on this method, examined PVD coatings produced the highest scuff resistance of all the tested face coatings.

A survey is made of compression brake noise levels in heavy duty diesel trucks, using test procedures based on the ISO and EPA driveby acceleration noise tests. The data shows that compression brake noise levels are very high if worn out or open stack exhaust systems are used. Compression brake noise is also audible with OEM exhaust systems and, in at least one case, potentially objectionable. Two methods for reducing brake noise are investigated: improved mufflers and the use of an exhaust brake with the compression brake. Both techniques demonstrate a potential for reducing compression brake noise.

This paper examines the feasibility of using the boundary element method (BEM) and the Rayleigh integral to assess the sound radiation from engine components such as oil pans. Two oil pans, one cast aluminum and the other stamped steel, are used in the study. All numerical results are compared to running engine data obtained for each of these oil pans on a Cummins engine. Measured running-engine surface velocity data are used as input to the BEM calculations. The BEM models of the oil pains are baffled in various ways to determine the feasibility of analyzing the sound radiated from the oil pan in isolation of the engine. Two baffling conditions are considered: an infinite baffle in which the edge of the oil pan are attached to an infinite, flat surface; and a closed baffle in which the edge of the oil pan is sealed with a rigid structure. It is shown that either of these methods gives satisfactory results when compared to experiment.

This paper documents the successful operation of a modified Cummins T46 turbocharger with a ceramic rotor. This turbocharger is modified to incorporate a 4.6 inch diameter ceramic turbine rotor (pressureless sintered silicon nitride) on the hot end. These results document the most complete ceramic turbine rotor performance map, for a large ceramic turbocharger rotor, available to date.

The EPA Heavy Truck Driveby Noise test is used to regulate trucks over 10,000 pounds GVW. The EPA test procedure is based on SAE J366. The EPA/J366 procedure is used both as a regulatory compliance tool and as a development tool. When the test procedure is used as a development tool, the goal is to determine the most cost effective means of meeting the legal requirement. Since J366 was not intended as a development tool, it can be difficult or misleading to use it to make decisions on product configuration. In order to use J366 successfully in vehicle or engine development, one must understand and properly account for the inherent variability of the J366 driveby test procedure. This paper examines both the extent and some of the sources of J366 driveby test variability. Strategies are proposed to ensure the proper interpretation of test results. Several repeat tests are required to accurately determine a small change in driveby noise level.

High Velocity Oxygen Fuel sprayed face coatings have shown great promise for piston rings used for High Power Density Diesel Engines. Various coatings have been tested on both wear test rigs and in engines. A highly dense HVOF cermet coating was developed with reasonable crack resistance during service. The HVOF coated piston rings wore three to six times lower than chrome plating. Cylinder liner (counter face) wear was found to be one to three times higher than chrome. However, engine oil consumption and blow by were within normal values. The HVOF coating is considered to be an excellent replacement for chrome plating. The coating process is more environmentally friendly than the chrome plating process. Also, the coating has potentially lower or equivalent production cost when compared to chrome.

A number of wear resistant coatings has been developed using physical vapor deposition(PVD) process. However this coating process has not yet been widely used in the automotive industry. The purpose of this work was to evaluate thin PVD coatings such as diamond like carbon doped with tungsten (W-DLC), molybdenum-disulfide doped with aluminum (MoS2-Al), and chrome nitride (CrN). Some of these coatings were previously found to have low friction, high wear resistance, or both when tested in unlubricated conditions. In the present work, the experiments were conducted using a Cameron-Plint apparatus in lubricated conditions. The ring counterfaces used were Cr-plated and gas-nitrided compression rings. Our data also indicated that some PVD coatings with thicknesses in the same order of magnitude as the surface roughness of the liners did show some improvement in liner wear resistance. The suitability of thin coatings for liner applications needs additional study.

In this paper, a procedure for the measurement of noise produced by compression brakes on heavy duty trucks is proposed and evaluated. The test procedure is an adaptation of the ISO exterior vehicle noise regulation, ISO 362, to measure compression brake noise. The test consists of two parts, a driveby test and a stationary brake test, which are both developed to accentuate compression brake noise. The proposed test is demonstrated to provide results that are indicative of on-road compression brake noise. The sensitivity of the test results to variations in several test parameters is also examined.

Evolving diesel engine design trends are expected to include fuel systems operating at significantly higher pressures and temperatures than in the past. Accordingly, meaningful laboratory tests are needed to help guide this development. Two candidate test methods were evaluated in this exploratory study. Scuffing Load Ball-on Cylinder Lubricity Evaluator (BOCLE) and Modified High-Frequency Reciprocating Rig (HFRR) test results covering a range of operating temperatures were compared with fuel property data. Correlations of the Modified HFRR test data with BOCLE results were also made.