ML20043F651
| ML20043F651 | |
| Person / Time | |
|---|---|
| Issue date: | 02/12/2020 |
| From: | Office of the Chief Human Capital Officer, Woodard Corp |
| To: | |
| Gary Callaway | |
| Shared Package | |
| ML20043F634 | List:
|
| References | |
| Download: ML20043F651 (4) | |
Text
Emergency Diesel Generator Glossary of Selected Terms Used in this Course APPENDIX E GLOSSARY OF TERMS Back Pressure The pressure existing in a fluid (gas or liquid) system resulting from its Acceleration Rate of change in velocity of physical configuration. Exhaust gas back a moving object, often specified in feet / sec2 pressure, for example, is the result of the (in math, the second derivative of position). resistance of the exhaust piping, work done in the turbocharger, and resistance to flow Aftercooler / Intercooler Heat exchanger through baffles in the silencer (muffler).
downstream from a blower, compressor, or turbocharger for reducing the temperature of BDC Bottom dead center. This term is the the compressed air, thereby increasing its opposite of Top Dead Center. It refers to the density. The denser air provides more location of the piston head at its farthest oxygen, allowing complete combustion of an point from the cylinder head, just before it increased amount of fuel (thus, more power) reverses direction. In a 4-stroke cycle and the lower temperature air charge into engine the end of the power stroke and the the cylinders helps cool valves and pistons. end of the intake stroke both occur at BDC.
ALCO Engine A 4-stroke cycle engine Bendix - An electrically or mechanically previously built by American Locomotive engaged, spring-retractable turning gear, Company (now out of business). It powers used primarily for engine starters. Originally EDG units at some nuclear power plants this referred only to products of the Bendix and is now manufactured and supported by Company but is becoming a generic term.
Fairbanks Morse.
Blower A mechanical driven air pumping API Oil Classification - The American device which provides an increased mass Petroleum Institute (API) designation for flow of scavenging and combustion air to the lubricating oil use ratings. Oils can be rated cylinders of a diesel engine. Required for for multiple applications. Diesel engine oils starting 2-stroke cycle diesel engines.
are indicated by the letter C (compression ignition) plus a suffix letter, as follows: Brake Horsepower (BHP) a measure of net power developed at the crankshaft of a CA - Light to moderate duty, normally diesel engine as measured by a device aspirated engines with low sulfur fuels. called a Prony Brake Dynamometer. One CB - Moderate duty, normally aspirated brake horsepower is equal to 33,000 foot-engines. pounds of work per minute.
CC - Moderate to somewhat severe duty, Brake Mean Effective Pressure (BMEP) turbocharged engines.
A theoretical term that refers to the mean CD - Severe duty, turbocharged engines. effective pressure acting on the piston that would produce its brake horsepower. Stress Atomization - Breaking up of liquids such on the engine is proportional to BMEP.
as diesel fuel oil into a fine mist to allow the fuel to effectively mix with the combustion air Brake Specific Fuel Consumption (BSFC) charge. The size and distribution of the tiny The quantity of fuel (in pounds) consumed fuel droplets is very important for efficient per brake horsepower (BHP) developed by combustion, which affects both the engines a diesel engine for a period of one hour. Its power output and exhaust emissions. expressed as pounds fuel per BHP hour.
Rev 3/16 E1 of 4 USNRC HRTD
Emergency Diesel Generator Glossary of Selected Terms Used in this Course Cetane Number A measure of the ignition Dynamometer A mechanical, electric, quality of diesel fuel oil, a key factor for hydraulic, or other device used to indicate engine starting and step load acceptance. It the power produced by a diesel engine by involves measuring the ignition delay of fuel applying a braking action and measuring the oil samples vs. a reference fuel. developed torque.
Clearance Volume The volume of an Efficiency, Mechanical The ratio of the engine cylinder with its piston at top dead power output (BHPBrake Horsepower) of center (TDC), assuming its a conventional the engine compared to the indicated power 2-stroke or 4-stroke cycle configuration. input (IHPIndicated Horsepower).
Compression Ratio The ratio of the Efficiency, Thermal The ratio of the heat cylinders maximum volume to its minimum equivalent of work output of a diesel engine volume, during a complete stroke. For a compared to the thermal input provided by conventional 2 or 4-stroke configuration the fuel oil, measured over a period of time.
these occur at BDC and TDC, respectively. One horsepower is equal to 2545 BTU / hr.
For an opposed piston (OP) engine the maximum and minimum volumes occur at Efficiency, Volumetric - In 4-stroke cycle, ODC & IDC, respectively. See OP Engine. non-turbocharged engines, this indicates the engines ability to breath. It is the ratio Crankcase Explosion The over of the mass of atmospheric air entering the pressurization of a diesel engine crankcase cylinder compared to the mass of air that when oil mist, fuel vapors, and oxygen in the would be contained in a volume equal to the engine crankcase are exposed to heat cylinder displacement.
sufficient to cause ignition. The heat source could be a failed bearing, sparks from EGA Governor Woodward electronic severe piston-cylinder scuffing, and / or governor with hydraulic actuator.
piston blow-by (failed rings).
EMD Engine - A 2-stroke cycle diesel Droop In an engine governing system, the engine originally built by the Electro-Motive change in speed (RPM) the unit makes Diesel division of General Motors. EMD, going from no-load to 100% rated load. Its Inc. is now a subsidiary of Caterpillar, Inc.
normally expressed as a % of nominal RPM.
For those familiar with proportional control Four-Stroke Cycle Engine A diesel systems, Droop is synonymous with Offset. engine that requires two engine revolutions for output power from each cylinder.
DRU Digital Reference Unit, used to provide speed reference signals for later Frictional Horsepower (FHP) The models of Woodward 2301A governors and portion of the indicated horsepower (IHP) some older governors. It can provide set developed by a diesel engine which is used points for idle, nominal RPM, and maximum to overcome the friction developed by the speed, as well as ramp rates for getting up operation of the engine.
to speed (or back down to idle) gradually, during test, to minimize wear and tear on the Governor A mechanical, hydraulic, engine. DRUs require input from a speed electric, or combination device that controls sensing device, typically an MPU. engine speed by regulating the fuel input.
Rev 3/16 E2 of 4 USNRC HRTD
Emergency Diesel Generator Glossary of Selected Terms Used in this Course GPM Gallons per minute. Pielstick Engine One of several 4-stroke cycle engine families produced by Fairbanks Horsepower See definitions for Brake, Morse. Others include ALCO and MAN.
Frictional, and Indicated Horsepower.
Pour Point The lowest temperature at Ignition Delay The time period between which a fuel or lubricating oil will flow with the point when fuel begins to be injected into relative ease.
the cylinder of a diesel engine until Power, Apparent - The power apparently combustion of the fuel actually begins. required to be supplied to or drawn from an AC system. Apparent power is measured in Indicated Horsepower (IHP) The volt-amperes (VA), kilovolt-amperes (kVA),
calculated total power developed by a diesel or Megavolt-amperes (MVA).
engine. Its a function of the mean indicated effective pressure applied to the top of the Power, Reactive The amount of electrical piston, the area of the piston, the length of power needed in AC machinery (motors, the stroke, and the power strokes / minute. generators, and transformers) to create the magnetic fields and voltage induction that Isochronous Governing the operation of enables them to function. This power is a diesel engine to maintain a constant speed measured in volt-amperes-reactive, or irrespective of the load applied to the VARs. It produces no work and so is engine. Therefore, zero Droop. sometimes referred to as imaginary power.
Lubricating Oil Analysis See Power, Real In an alternating current (AC)
Spectrographic Lubricating Oil Analysis. system this is the true electrical power that is converted to mechanical energy, such as MOP - A motor operated potentiometer is a motor driving a pump. This power is used to vary voltage to a device. In some customarily measured in kilowatts (kW).
older models of diesel engine governors an MOP is used for speed control. Power Factor The ratio of Real Power to Apparent Power. It is a measure of the MPU - Magnetic pick-up coil, used in some utilization of the input power of a system, or EDG systems for engine speed sensing. By equipment. Generators are typically rated mounting close to the engine flywheel gear for a power factor of 80%.
teeth, as each one passes by it changes the magnetic field, producing a pulse signal that PSIG Pounds-per-square-inch gauge.
the governor can translate into engine RPM and make fuel adjustment as needed. Pyrometer An electrical temperature measuring device, usually connected to a OP Engine Fairbanks Morse Opposed thermocouple, used to measure high Piston Engine. A 2-stroke cycle engine with temperature such as diesel engine exhaust two opposing pistons sharing each cylinder gas temperature.
bore. Ports are used for intake and exhaust (no valves). The term BDC doesnt fit and Scavenging Intake air blowing out is replaced by Outer Dead Center (ODC). exhaust gases prior to providing combustion Likewise, TDC is replaced by Inner Dead air for the next power stroke. Blowers and Center (IDC). turbochargers provide scavenging air.
Rev 3/16 E3 of 4 USNRC HRTD
Emergency Diesel Generator Glossary of Selected Terms Used in this Course Specific Gravity Ratio of the density of a Thermostat A device that senses the substance, fuel, or lube oil to the density of temperature of the engine coolant and water. Water has a specific gravity of 1. causes a change in the rate or direction of Diesel fuel oil has a specific gravity less than coolant flow, to maintain the desired engine 1, so it floats on water (the latter normally temperature.
settling to the bottom of fuel tanks). Torsional Vibration Vibration caused by Specific Heat The amount of heat energy twisting of the crankshaft due to the cyclical required to raise the temperature of 1 pound production of power from each of the engine of a substance 1oF expressed in British cylinders. This results in localized stresses thermal units, Btu (or BTU). The specific that can cause crankshaft metal fatigue and heat of water is 1 Btu per pound per oF. possible failure, unless moderated by anti-resonant / torsional dampers.
Spectrographic Lubricating Oil Analysis A method of oil analysis where a sample of Turbocharger A mechanical device, lubrication oil is taken from a diesel engine powered by thermal energy of the diesel and burned in a special furnace. The light engine exhaust gases, that incorporates a emitted by its combustion provides spectral centrifugal compressor to increase the mass indication of the type and quantity of wear air flow to the engine cylinders. Increased metals and contaminants in the lube oil. air (oxygen) allows more fuel to be burned, Results are logged and compared to thereby increasing engine power.
previous data. Trends can indicate incipient or impending problems with the engine. Two-Stroke Cycle Engine A diesel engine that requires one engine revolution Supercharging Increases the mass flow for output power from each cylinder. In two-of combustion air to the engine cylinders stroke cycle engines, camshaft speed is the beyond that achieved by natural aspiration. same as crankshaft speed.
Turbochargers are engine exhaust-driven superchargers. Blowers for 2-stroke cycle Viscosity A measure of the resistance to engines are usually driven by the engine. flow of lubricating and fuel oils. Viscosity is Turbochargers recover power that otherwise a function of temperature. As the would be lost in the exhaust stream, temperature increases, the viscosity of the primarily as heat. oil decreases (becomes thinner).
TDC Top Dead Center. The opposite of Viscosity Index (VI) The viscosity index Bottom Dead Center. It refers to location of of an oil indicates how the oil is affected by the piston at its closest approach to the changes in temperatures. A high viscosity cylinder head, just before it reverses index indicates the oil experiences little direction. In a 4-stroke cycle engine the end change in viscosity as the temperature of of the compression stroke and the end of the the oil changes.
exhaust stroke both occur at TDC.
Thermocouple A temperature measuring device composed of two dissimilar metals joined at their ends. When heat is applied to the joint, a voltage is developed across the opened end and its magnitude gives temp.
Rev 3/16 E4 of 4 USNRC HRTD