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Building on two decades of expertise, a fourth generation fleet test protocol is presented for assessing the response of engine performance to gasoline additive treatment. In this case, the ability of additives to remove pre-existing deposit from the intake systems of port fuel injected vehicles has been examined. The protocol is capable of identifying real benefits under realistic market conditions, isolating fuel performance from other effects thereby allowing a direct comparison between different fuels. It is cost efficient and robust to unplanned incidents. The new protocol has been applied to the development of a candidate fuel additive package for the North American market. A vehicle fleet of 5 quadruplets (5 sets of 4 matched vehicles, each set of a different model) was tested twice, assessing the intake valve clean-up performance of 3 test fuels relative to a control fuel.

The US Army is currently assessing the feasibility and defining the requirements of a Single Common Powertrain Lubricant (SCPL). This new lubricant would consist of an all-season (arctic to desert), fuel-efficient, multifunctional powertrain fluid with extended drain capabilities. As a developmental starting point, diesel engine testing has been conducted using the current MIL-PRF-46167D arctic engine oil at high temperature conditions representative of desert operation. Testing has been completed using three high density military engines: the General Engine Products 6.5L(T) engine, the Caterpillar C7, and the Detroit Diesel Series 60. Tests were conducted following two standard military testing cycles; the 210 hr Tactical Wheeled Vehicle Cycle, and the 400 hr NATO Hardware Endurance Cycle. Modifications were made to both testing procedures to more closely replicate the operation of the engine in desert-like conditions.

The Dedicated EGR (D-EGR®) engine has shown improved efficiency and emissions while minimizing the challenges of traditional cooled EGR. The concept combines the benefits of cooled EGR with additional improvements resulting from in-cylinder fuel reformation. The fuel reformation takes place in the dedicated cylinder, which is also responsible for producing the diluents for the engine (EGR). The D-EGR system does present its own set of challenges. Because only one out of four cylinders is providing all of the dilution and reformate for the engine, there are three “missing” EGR pulses and problems with EGR distribution to all 4 cylinders exist. In testing, distribution problems were realized which led to poor engine operation. To address these spatial and temporal mixing challenges, a distribution mixer was developed and tested which improved cylinder-to-cylinder and cycle-to-cycle variation of EGR rate through improved EGR distribution.

The use of fuel additives is one possible approach to reduce wear and corrosion in methanol fueled automobile engines. One hundred and six compounds added to M100 fuel in modest concentrations (1%) were tested in a Ball on Cylinder Machine (BOCM) for their ability to improve lubricity. The most promising candidates were then tested in an engine using a modified ASTM Sequence V-D wear screening test. Additive performance was measured by comparing the buildup of wear metals in the oil to that obtained from an engine fueled with neat M100. The BOCM method of evaluating the additive candidates proved inadequate in predicting abrasive engine wear under the test conditions utilized for this research program.

The key words in the marketplace for off-highway vehicles are durability, performance, and efficiency. A manufacturer of these vehicles recognizes that one way to successfully address these needs is by a well thought through electronics design. With the computer sophistication now being incorporated into off-highway vehicles, engineers must work closely to assure electromagnetic compatibility (EMC) of the entire system. A properly established EMC program extending from concept to final design will support each of a product's specified operations and still function as an integrated whole. This paper describes the process for designing the EMC for an off-highway vehicle.

A cooperative research and development program was organized to determine the critical particle size of abrasive debris that will cause significant wear in rotary injection fuel pumps. Various double-cut test dusts ranging from 0-5 to 10-20 μm were evaluated to determine which caused the pumps to fail. With the exception of the 0-5-μm test dust, all other test dust ranges evaluated caused failure in the rotary injection pumps. After preliminary testing, it was agreed that the 4-8-μm test dust would be used for further testing. Analysis revealed that the critical particle size causing significant wear is 6-7 μm. This is a smaller abrasive particle size than reported in previously published literature. A rotary injection pump evaluation methodology was developed. During actual operation, the fuel injection process creates a shock wave that propagates back up the fuel line to the fuel filter.

The API has established lubricant specifications, which include standard tests for ring and liner wear. The Mack T-10 is one such test, performed on a prototype engine with Exhaust Gas Recirculation (EGR). At EOT, the liner wear is measured by profilometry, while the ring wear is measured by weight loss. It was decided to monitor the wear of the rings and liners during a full-length T10 test in order to observe the evolution of the wears and wear rates over the course of the test, by using the Surface Layer Activation (SLA) and Bulk Activation (BA) techniques. Three different radioisotopes were created, one in the liners at the turnaround zone, one in the chromium-containing coating on the ring faces, and one in the iron bulk of the rings. This enabled us to observe the wear characteristics of these three components separately. In particular, we were able to separate the face and side ring wears, which cannot be done with simple weight-loss measurements.

The critical particle size for a high-pressure injection system was determined. Various double-cut test dusts ranging from 0 to 5 μm to 10 to 20 μm were evaluated to determine which test dust caused the high-pressure system to fail. With the exception of the 0- to 5-μm test dust, all test dust ranges caused failure in the high-pressure injection system. Analysis of these evaluations revealed that the critical particle size, in initiating significant abrasive wear, is 6 to 7 μm. Wear curve formulas were generated for each evaluation. A formula was derived that allows the user to determine if the fuel filter effluent will cause harmful damage to the fuel system based on the number of 5-, 10-, and 15-μm particles per milliliter present. A methodology was developed to evaluate fuel filter performance as related to engine operating conditions. The abrasive methodology can evaluate online filter efficiency and associated wear in a high-pressure injection system.

In off-highway applications the engine torque is distributed between the transmission (propulsion) and other accessories such as power steering, air conditioning and implements. Electronic controls offer the opportunity to more efficiently manage the control of the engine and transmission as an integrated system. This paper deals with development of a steepest descent algorithm for maximizing the efficiency of hydrostatic transmission along with the engine in the presence of accessory load. The methodology is illustrated with an example. The strategy can be extended to the full hydro-mechanical configuration as required. Applications of this approach include adjusting for component wear and intelligent energy management between different accessories for possible size reduction of powertrain components. The potential benefits of this strategy are improved fuel efficiency and operator productivity.

While standardized laboratory-scale wear tests are available to predict the lubricity of liquid fuels under ambient conditions, the reality is that many injection systems operate at elevated temperatures where fuel vaporization is too excessive to perform the measure satisfactorily. The present paper describes a High Pressure High Frequency Reciprocating Rig (HPHFRR) purposely designed to evaluate fuel lubricity in a pressurized environment at temperatures of up to 300°C. The remaining test parameters are identical to those of the widely standardized High Frequency Reciprocating Rig (HFRR). Results obtained using the HPHFRR indicate that wear rate with poor lubricity fuels is strongly sensitive to both temperature and oxygen partial pressure and may be orders of magnitude higher than at ambient conditions. Surprisingly however, wear rate was found to decrease dramatically at temperatures above 100°C, possibly due to evaporation of dissolved moisture.

The U.S. Army's National Automotive Center has contracted with Illinois Institute of Technology Research Institute (IITRI), Southwest Research Institute (SwRI), and Advanced Propulsion, LLC, to evaluate the effects on fuel consumption and logistics that would result from hybridizing the powertrains of the Army's tactical wheeled vehicle fleet. This paper will outline the approach taken to perform that evaluation and present a synopsis of results achieved to date.

Twelve different hole shapes for diesel injector tips were characterized with DF-2 diesel fuel for spray cone angle over a range of injection pressures from 21 MPa (3 kpsi) to 69 MPa (10 kpsi). A baseline and two of the most radical designs were also tested for drop-size distribution and liquid volume fraction (liquid fuel-air ratio) over a range of pressures from 41 MPa (6 kpsi) to 103 MPa (15 kpsi). All hole shapes were circular in cross-section with minimum diameters of 0.4 mm (0.016 in.), and included converging and diverging hole shapes. Overall hole lengths were constant at 2.5 mm (0.098 in.), for an L/d of 6.2. However, the effective L/d may have been less for some of the convergent and divergent shapes.

This paper is the second of two that describe the effects of low-lubricity fuels on diesel injection pump performance. The first paper describes the primary failure mechanisms and wear processes in a number of failed pumps removed from both military and civilian vehicles that had been operated on Jet A-1 and diesel fuels. However, the multitude of unregulated parameters in practical operation renders quantitative comparison between different fuels and pump combinations impractical. This paper describes the degradation in pump performance and the wear processes associated with fuels of varying lubricity in the well-defined environment of a pump test stand. The test methodology concentrates on those areas previously demonstrated to be most susceptible to wear. The results indicate that pump durability is reduced by highly refined low-viscosity fuels, but may be successfully counteracted by either improved metallurgy or lubricity additives.

The study described in this paper covers the development of the Sequence IVB low-temperature valvetrain wear test as a replacement test platform for the existing ASTM D6891 Sequence IVA for the new engine oil category, ILSAC GF-6. The Sequence IVB Test uses a Toyota engine with dual overhead camshafts, direct-acting mechanical lifter valvetrain system. The original intent for the new test was to be a direct replacement for the Sequence IVA. Due to inherent differences in valvetrain system design between the Sequence IVA and IVB engines, it was necessary to alter existing test conditions to ensure adequate wear was produced on the valvetrain components to allow discrimination among the different lubricant formulations. A variety of test conditions and wear parameters were evaluated in the test development. Radioactive tracer technique (RATT) was used to determine the wear response of the test platform to various test conditions.

Since the invention of the internal combustion engine, the contact between piston ring and cylinder liner has been a major concern for engine builders. The quality and durability of this contact has been linked to the life of the engine, its maintenance, and its exhaust gas and blowby emissions, but also to its factional properties and therefore fuel economy. While the basic design has not changed, many factors that affect the performance of the ring/liner contact have evolved and are still evolving. This paper provides an overview of observations related to the lubrication of the ring/liner contact.

The dual-fuel combustion process of ethanol and n-heptane was characterized experimentally in an optically accessible engine and numerically through a chemical kinetic 3D-CFD investigation. Previously reported formaldehyde PLIF distributions were used as a tracer of low-temperature oxidation of straight-chained hydrocarbons and the numerical results were observed to be in agreement with the experimental data. The numerical and experimental evidence suggests that a change in the speed of flame propagation is responsible for the observed behavior of the dual-fuel combustion, where the energy release duration is increased and the maximum rate of pressure rise is decreased. Further, an explanation is provided for the asymmetrical energy release profile reported in literature which has been previously attributed to an increase in the diffusion-controlled combustion phase.

Measurement of emissions from small utility engines has usually been accomplished using steady-state raw emissions procedures such as SAE Recommended Practice J1088. While raw exhaust measurements have the advantage of producing modal exhaust gas concentration data for design feedback; they are laborious, may influence both engine performance and the emissions themselves, and have no provision for concurrent particulate measurements. It is time to consider a full-dilution procedure similar in principle to automotive and heavy-duty on-highway emission measurement practice, leading to improvements in many of the areas noted above, and generally to much higher confidence in data obtained. When certification and audit of small engine emissions become a reality, a brief dilute exhaust procedure generating only the necessary data will be a tremendous advantage to both manufacturers and regulatory agencies.

Soil samples were collected from various geographical areas in the United States and Saudi Arabia. The samples were obtained from U.S. military installations at which off-road maneuvers are conducted. Saudi Arabia samples were obtained from the deserts surrounding Riyadh. The samples were characterized using particle size distributions, elemental analysis, mineral composition and particle angularity. Particle size distributions were determined for simulated fuel cells with intermittent and continual mixing. The results obtained from the world-wide soil sample analyses were compared against AC and PTI SAE fine and coarse test dust results.

High-speed movie films, and laser-diffraction drop sizing were used to evaluate the structure, penetration rate, cone angle, and drop size distribution of diesel sprays in a constant volume pressure vessel. As further means of evaluating the data, comparisons are made between the film measurements, and calculations from a dense gas jet model. In addition to the high-speed film data that describes the overall structure of the spray as a function of time, a laser diffraction instrument was used to measure drop size distribution through a cross-section of the spray. In terms of the growth of the total spray volume (a rough measure of the amount of air entrained in the spray), spray impingement causes an initial delay, but generally the same overall growth rate as an equivalent unimpeded spray. Agreement between measurements and calculations is excellent for a diesel spray with a 0.15 mm D orifice and relatively high injection pressures.

Radioactive tracer technology (RAT) is an important tool in measuring component wear in an operating engine on a real-time basis. This paper will discuss the use of RAT to study and evaluate boundary lubricant and surfactant chemistries aimed at providing benefits in wear control. In particular, RAT was employed to study ring and bearing wear as a function of engine operating condition (speed, load, and temperature) and lubricant characteristics. Prior to testing, the engine's compression rings and connecting rod bearings were subjected to bulk thermal neutron bombardment in a nuclear reactor to produce artificial radioisotopes that were separately characteristic of the ring and bearing wear surfaces. The irradiated parts were installed in the test engine, after which testing to a specific test matrix was accomplished.