Single Cylinder Preparation.

Originally, the proposed single-cylinder engine was to be prepared by Mack Truck Inc., but it has been replaced by the Cummins single-cylinder AIPS engine. Adiabatics, Inc. assumed full responsibility for its preparation in one year rather than the original 28 months.

Extensive support was received from Cummins Engine Company while Mack Truck Inc. played a consulting role to Adiabatics, Inc. An AVL 532 single-cylinder base engine is being used with the Cummins AIPS powerhead. The program engine is composed of a . high BMEP version of the AVL basic engine unit which houses the lower end of the engine (crankshaft, balancers, flywheel, etc.) with a custom designed block, cylinder, connecting rod, piston, cylinder head, camshaft, fuel system, etc. A typical engine system is shown in Figure 12. Note that the engine provides three individual

Figure 12. AVL Single-Cylinder Engine.

lubricant systems. This allows the assessment of smaller controlled quantities of specialty lubricants. It also provides isolation of damage which protects cylinder head and balancer components from contamination in case of a cylinder failure.

The engine which is being built for this program is being built to the following specifications and capabilities:

• Non-water-cooled

• Brake mean effective pressure

- 300 psi at peak torque

- 240 psi at rated power

The intake handling system being used is a rather novel design which utilizes turbochargers to provide intake boost. This system is illustrated in Figure 13. This system has two turbochargers placed in series with two aftercoolers. The system is designed to provide an air flow of 1400 lb /hr at 66 psia intake pressure. This system is unique in that it approaches a true self-sustained multi-cylinder engine system which does not depend on a complex overburdened support system. This turbocharged SCE system allows a truer assessment of overall heat rejection which includes aftercooling, etc. Important parameters such as the air-fuel ratio and the intake boost level can be varied by merely controlling turbo exhaust mass flow with a by-pass valve.

The full-size AVL-SCE is scheduled to be in full operation by December, 1987 with full test cell instrumentation. At this time a shake down of the system will be completed with the first in-cyUnder component and advanced high temperature lubricant screening to follow.

Advanced Tribolocrical Systems

Future U.S. Army LHR diesel engines will operate with oil sump temperatures of approximately 350 degrees F, and cylinder wall temperatures (at the TRR position) greater than 700 degrees F, up to a maximum of 1100 degrees F. This thermal environment is more severe than that projected for the commercial LHR engines under consideration in U.S. Department of Energy programs. The technology we are developing for military diesel engines can be transferred to the less severe operating environments of commercial diesel engines.

Tribological system development on our program has concentrated on the development and evaluation of new liquid-based diesel engine lubricants. Selection and evaluation of wear-resistant coatings for piston exhaust damper

exhaust damper

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