Guide to Engine Makers

The following list of engine manufacturers is intended only as a general guide to companies in the UK, Europe, Japan, and North America (excluding eastern Europe and the USSR) which make industrial prime movers of the types discussed in this book. Such companies are good sources of further technical information about engine design and development for the reader who seeks additional data.

The list was compiled early in 1971, and changes in company names, addresses, and range of engines produced are to be expected. It is not a comprehensive directory, and the omission of any company from the list is no reflection on their status in the industry.

The guide is directed to makers of engines primarily intended for stationary on-land industrial applications (and for some automotive uses). There are several manufacturers who supply diesel engines in the very high power ranges, but these are strictly for marine use, and data about them are not included.

A key to type/power-range is given on pl78.

UNITED KINGDOM

W HAllen Sons & Co Ltd, Queens Engineering Works, Bedford. D2D3D4

Auto Diesels Braby Ltd, Cowley Mill Road, Uxbridge, Middlesex. Gl G2

Bamfords Ltd, Uttoxeter, Staffs. D1

British Leyland Motor Corporation Ltd., Leyland, Lanes PR5 lSN Sl D1 D2G2

British Polar Engines Ltd, Govan, Glasgow, Scotland. D2D3D4

David Brown Tractors (Sales) Ltd, Huddersfield, HD7 3AR D1

177

John Brown Engineering (Ciydebank) Ltd, Clydebank, Dunbartonshire. G4GS

David Budworth Ltd, Harwich, Essex. G2

Caterpillar Tractor Co Ltd, PO Box 162, Glasgow, Scotland. Dl D2

Centrax Ltd, Shalden Road, Newton Abbot, Devon. G3

Chrysler (UK) Ltd, Dunstable, Bedfordshire. D1

Coventry Climax Engines Ltd, Browns Lane, Coventry, CVl 4DX Sl S2 D1

Coventry Victor Motor Co Ltd, Binley, Coventry, CV3 2AR D1

Crossley Premier Engines Ltd, PO Box 1, Manchester, Mll 2DP D3 D4 DS

Cummins Engine Co Ltd, Coombe House, Malden Road, New Malden, Surrey. D2D3

Dorman Diesels Ltd, Tixall Road, Stafford. S2 Dl D2 D3

Doxford & Sunderland Shipbuilding and Engineering Co Ltd, PO Box 25, Sunderland, Co. Durham. D4DS

Enfield Industrial Engines Ltd, Somerton Works, Cowes, Isle of Wight. Dl

GEC - English Electric Gas Turbines Ltd, Whetstone, Leicester, LE8 3LH G3 G4 GS

Fodens Ltd, Elworth Works, Sandbach, Cheshire. Dl D2

Ford Motor Co Ltd, Brentwood, Essex. Sl D1 D2

Gardner Engines (Sales) Ltd, Patricroft, Manchester, M30 7WA Dl D2

General Motors Ltd, P&I Division, Wellingborough, Northants, NN8 2DL D1 D2 D3

Hawthorn Leslie (Engineers) Ltd, St. Peter's Works, Newcastle-on-Tyne, NE99 lPD D4DS

R A Lister & Co. Ltd, Dursley, Glos, GLll 4HS Dl D2

Mirrlees Blackstone Ltd, Stockport, Cheshire. Dl D2 D3 D4

Norton Villiers Ltd, Wolverhampton, Staffs. Pl

F Perkins Ltd, Peterborough, PEl 5NA Sl D1 D2

Petters Ltd, Staines, Middlesex. Dl

John Robson (Shipley) Ltd, Shipley, Yorks. D1

178

KEY

Engine type S - Spark ignition D -Diesel G - Gas turbine

Power range 1 = 0-100 kW 2 = 100-500 kW 3 = 500-2000 kW 4 = 2000-10 000 kW 5 = over 10 000 kW

Russell Newbery & Co Ltd, Freshwater Road, Chadwell Heath, Essex. D1 D2

Rolls-Royce (1971) Ltd, Industrial and Marine Division, PO Box 72, Ansty, nr Coventry, CV7 9JR G4GS

Rolls-Royce Motors Ltd, Diesel Division, Shrewsbury, SY14DP D1 D2

Rover Gas Turbines Ltd, Holyhead Road, Coventry. Gl

Ruston Gas Turbines Ltd, PO Box 25, Lincoln. G3G4

Ruston Paxman Diesels Ltd, Vulcan Works, Newton-le-Willows, Lanes. D2D3 D4

CONTINENTAL EUROPE

AIFO SpA, 20123 Milano, Italy. Sl Dl D2 D3

Societe Alsacienne de Constructions Mecaniques de Mulhouse, (68) Mulhouse, France. D2 D3 D4

Atlas-Mak Maschinenbau Gmbh, Postfach 9009, 23 Kiel17, West Germany. D2D3 D4

Baudouin- Societe des Moteurs Baudouin, 165 Boulevard de Pont-de-Vivaux, 13 Marseille, France. D1 D2D3

Belgodiesel, 60 Rue Royal, 1000 Bruxelles, Belgium. D2D3 D4

Bernard-Moteurs SA, 12 Rue Mederic, Paris, France. Dl

Bolnes Maschienefabriek NV, PO Box 3, Krimpen a/d Lek, Holland. D4

Brown Boveri-Sulzer Turbomachinery Ltd, Zurich, Switzerland. G4GS

Motorfabriken Bukh A/S, Dk4400, Kalundborg, Denmark Dl

Burmeister & Wain AB, Copenhagen K, Denmark. D2D3

CLM- Societe Commerciale de Moteurs, 49 Rue Noel Pons, 92 Nan terre, France. Dl

Daimler Benz AG, 7 Stuttgart 60, West Germany. Sl D1 D2

Farymann Diesel, 6840 Lampertheim/Hessen, West Germany. D1

Fiat Grandi Motori, Via Cuneo 20, 10100 Torino, Italy. Sl D1 D2 D3 D4 DS G4 GS

Ganz-Mavag, PO Box 136, Budapest 70, Hungary. D2D3

179

Hanomag-Henschel, PO Box 786, 35 Kassel 2, West Germany. D1 D2

Hatz Motorenfabrik GmbH, 8399 Ruhstorf/Rott bei Passau, West Germany. Dl

Hispano-Suiza Division of SNECMA, Rue du Capitaine Guynemer, 92 Bois-Colombes, France. G4G5

Isotta Fraschini e Motori Breda, Via Milano 7, Saronno, Italy. D2D3

Jenbacher Werke AG, Jenbach, Austria. D1 D2 D3 D4

JLO-Werke GmbH, 208 Pinneberg, Ander Miihlenau 12-14, West Germany. Sl

Klockner-Humboldt-Deutz AG, PO Box 440, 5000 Koln-Deutz 1, West Germany. D1 D2 D3 D4 Gl

AS Kongsberg V~penfabrickk, Kongsberg, Norway. G3

Kraftwerk Union AG, Miilheim/Ruhr, West Germany. G4G5

Lombardini Fabbrica ltaliana Motori SpA, Via F Manfredi 6, Reggio Emilia, Italy. Sl D1

MAG, Motosacoche SA, Route des Acacias 56, Geneva 24, Switzerland. D1

Maschinenfabrik Augsburg-Niirnberg AG, Werk Augsburg, Augsburg, West Germany. D2 D3 D4 DS G2

Motoren und Turbinen Union Friedrichshafen GmbH, 799 Friedrichshafen, West Germany. D2 D3 D4

Motorenfabrik Anton Schluter Miinchen, 805 Freising, West Germany. Dl D2

Motori Marini lndustriali SpA, Sona, Verona, Italy. Sl

M WM Motoren-Werke-MannheimAG, Carl-Benz Strasse 68, Mannheim 1, West Germany. D1 D2 D3 D4

NOHAB (Polar), Trollhatten, Sweden. D2 D3 D4

Nuovo Pignone, Via Matteucci 2, 50100 Firenze, Italy. D3 D4G4G5

Pegaso- Empressa Nacional de Autocamiones SA, Calle Ia Segrera 179-197, Barcelona, Spain. Dl D2

Peugeot-lndenor- See CLM.

Pielstick-SEMT, 2 Quai de Seine, 93 StDenis, France. D3 D4 DS

Renault- Regie Nationale des Usines Renault, 92 Boulogne-Billancourt, France. Sl D1 D2

Rotax-Werk AG, Gunskirchen, Austria Sl

Saab-Scania, S-151 87 Sodertiilje, Sweden. Dl D2

SKL VEB Schwermaschinenbau, Karl Liebknecht, 3011 Magdeburg, German Democratic Republic D1 D2 D3 D4 DS

180

SNECMA - See Hispano-Suiza.

Skoda-Pragoinvest, PO Box 890, Praha 9, Czechoslovakia. D1 D2D3 D4

Smit & Bolnes Motorenfabriek NV, Zierikzee, Holland. D3D4

Stal-Laval Turbin AB, S-612 20 Finspong, Sweden. GS

Stork-W.erkspoor Diesel NV, PO Box 4196, Amsterdam, Holland. D4 DS G3 G4 GS

Sulzer Brothers Ltd, 8401 Winterthur, Switzerland. D4DS

Thomassen Motorenfabriek NV, De Steeg, Holland. S3 S4 G4 GS

VanDoorne's Automobielfabriek NV, Eindhoven, Holland. Sl D2

Volkswagenwerk AG, 3180 Wolfsburg, West Germany. Sl

Volvo-Penta AB, PO Box 392, S-401 26 Goteborg, Sweden. Sl S2 Dl D2

VM Motori SpA, Via Ferrarese 29, Cento (Ferrara), Italy. D1 D2

JAPAN

KEY

Engine type S - Spark ignition D- Diesel G - Gas turbine

Daihatsu Diesel Mfg Co Ltd, 1-chome, Oyodo-cho, Oy,odo-ku, Osaka. D1 D2 D4

lsuzu Motors Ltd, Shinagawa-ku, Tokyo. D1 D2

Kawasaki Heavy Industries Ltd, Engine Division, Minato-ku, Tokyo. Sl D1

Mitsubishi Heavy Industries Ltd, 5-1 Marunouchi, 2-chome, Chiyoda-ku, Tokyo. Sl D1 D2 D3 D4 DS G2 G3 GS

Niigata Engineering Co Ltd, No 27-7, Taito 2-chome, Taito-ku, Tokyo. D2 D3 D4DS

Nissan Diesel Motor Co Ltd, 3-7-1, Kanda Nishiki-cho, Chiyoda-ku, Tokyo. D1 D2

Yanmar Diesel Engine Co Ltd, 62 Chayamachi, Kita-ku, Osaka .. Sl D1 D2 D3

Power range 1 = 0-100 kW 2 = 100-500 kW 3 = 500-2000 kW 4 = 2000-10 000 kW 5 =over 10 000 kW

181

UNITED STATES

Alco Engine Division, White Industrial Power Inc, 100 Orchard Street, Auburn, NY 13021. D203 04

Allis-Chalmers Manufacturing Co, PO Box 563, Harvey, 11160426. Sl D1 02

Allison Division, General Motors Corp, 4700 W lOth Street, Indianapolis, Indiana 46206. G4

Avco Lycoming Industrial Division, Williamsport, Pa 17701. Sl D1

Briggs & Stratton Corp, Milwaukee, Wisconsin Sl

Avco Lycoming Division, Gas Turbine Dept, 550 S Main Street, Stratford, Conn 06497. G3G4

Caterpillar Tractor Co, Industrial Division, PO Box 1108, Peoria, Ill61602 01 0203G2

Chicago Pneumatic Tool Co, 6 East 44th Street, New York, NY 10017. S2 S3 0203 04

Chrysler Corp, Industrial Products Div, PO Box 1, Marysville, Mich 48040. D1 02

Cooper-Bessemer Div of Cooper Industries Inc, Mount Vernon, Ohio 43050. 03 04G4GS

Continental Aviation and Engineering Corp, 12700 Kercheval, Detroit, Mich 48215. G2G3

Cummins Engine Co Inc, 1000 Fifth Avenue, Columbus, lnd 47201. 0203

Curtiss-Wright Corp, Power Systems, 1 Passaic Street, Wood-Ridge, NJ 07075 G4GS

KEY Engine type S - Spark ignition D- Diesel G - Gas turbine Power range 1 = 0-100 kW 2 = 100-500 kW 3 = 500-2000 kW 4 = 2000-10 000 kW 5 =over 10 000 kW

Detroit Diesel Engine Division, General Motors Corp, 13400 West Outer Drive, Detroit, Mich 48228. 0102 03

Dresser Industries Inc, 3201 Wolf Road, Franklin Park, 11160131. 0203 04DS GS

Electro-Motive Division, General Motors Corp, LaGrange, Ill 60525. 0304

Energy Transformation Corp, Swinehart & Rick Roads, Boyertown, Pa 19512. Gl

Enterprise Div, De Laval Turbine Inc, 550 85th Avenue, Oakland, Calf 94621 0203 04

Fairbanks Morse, Colt Industries Inc, Power Systems Div, 701 Lawton Ave, Beloit, Wis 53511. 0203 0405

Ford Industrial Power Products, Industrial Engine and Turbine Operations, Village Plaza, 23400 Michigan Avenue, Dearborn, Mich 48124.

Sl S2 D1 02 G2

Garrett Corp, AiResearch Manufacturing Div, 402 S 36th Street, Phoenix, Arizona. Gl G2 G3

General Electric Co, Gas Turbine Dept, 1 River Road, Bldg 53, Schenectady, NY 12305. G4GS

GMC Truck and Coach Div, General Motors Corp, 660 S Blvd East, Pontiac, Mich 48053 S202

182

Hercules Engines Inc, 101 Eleventh Street SE, Canton, Ohio 44702. Sl S2 D1 02

Ingersoll-Rand Co, Phillipsburg, NJ 08865. G4GS

International Harvester Co, PO Box 270, Melrose Park, Ill 60160. Sl S2 D1 02

Minneapolis-Moline Inc, Hopkins, Minn 55343. Dl 02

Murphy Diesel Co, 5317 W Burnham Street, Milwaukee, Wis 53219. D1 02

Nordberg Manufacturing Co, 3073 S Chase Avenue, Milwaukee, Wis 53201. 03 D4G4

Onan Division of Studebaker Corp, 1400 73rd Avenue NE, Minneapolis, Minn 55432. Sl Dl

Power Technology Corp, 105 Enterprise Drive, Ann Arbor, Mich 48103. Gl

Pratt & Whitney Aircraft Div, East Hartford, Conn 06108. G3 G4GS

Solar Division of International Harvester Co, 2200 Pacific Highway, San Diego, Calif 92112. Gl G2 G3

Sterling Engine Co, 3600 NW North River Drive, Miami, Fla 33148. D1 02

Teledyne Continental Motors, 12700 Kercheval Avenue, Detroit, Mich 48215. Sl S2 D1 02

Turbotech Inc, PO Box 5453, New York, NY 10017. G4GS

Universal Diesel Engines, 1550 Harrison Street, Oshkosh, Wis 54901. Dl

Waukesha Motor Co, Waukesha, Wis 53186. D1 D2D3G2

Westinghouse Electric Corp, Lester, Pa 19113. GS

White Superior Division of White Motor Corp, PO Box 540, Springfield, Ohio 45501. 02 03 04

Witte Engine Corp, 555 East 56 Highway, Olathe, Kansas 66061. Dl

Worthington Compressor & Engine International PO Box 69, Buffalo, NY 14240. 02 0304

CANADA

Orenda Ltd, Box 6001, Toronto International Airport, Toronto, Ontario. G3 G4GS

United Aircraft of Canada Ltd, PO Box 10, Longueuil, Quebec. G3

183

Accelerated ageing test: subjects a product to intensified but controlled conditions of heat, pressure, radia­tion or other factors to produce, in a short time, the effects of long­time storage or use under normal conditions.

Acid recovery plant: for recovery of sulphuric acid from acid sludge.

Acid sludge (tar): material of high relative density (sp gr) formed during chemical refining of oils by sulphuric acid; can usually be separated by settling or centrifuging.

Additives (oil): substances added to petroleum fractions to modify their natural properties; eg tetraethyl lead to improve gasoline octane num­ber (anti-knock additive); special materials for production of detergent oils.

After running: running on. Air cell (diesel): combustion chamber

system in which fuel is injected into the main chamber (open to the cylinder, as in open chamber design) which is connected by narrow throat(s) to one or more air cells in which rapid secondary combustion takes place; uses high proportion of air charge; is suitable for automotive uses.

Air injection: applied in a fuel system to force a fuel charge into a com­bustion, or pre-combustion, space; uses highly compressed air.

Alternative fuel engine: designed to operate (i) on fuel alone with com­pression ignition, or (ii) solely on gaseous fuel ignited by a spark; fuel conversion is possible while the engine is running.

Anti-knock compound (additive): typically tetraethyl or tetramethyl lead, added to gasolines to improve octane number (knock rating).

Anti-knock value: resistance of a fuel to conditions that cause explosive combustion (knocking) of fuel-air mixture in a spark-ignition engine; related to octane number.

ASME: American Society of Mechanical Engineers.

ASTM: American Society for Testing and Materials; issues standards, tests, and procedures; (eg ASTM 088-56, Saybolt viscosity).

GLOSSARY OF TERMS

Auto-ignition: spontaneous (auto­genous) ignition, particularly of air­fuel mixture in an internal­combustion engine.

Availability: (of plant/machinery) can be expressed as = 100 X (plant running time) divided by the sum of (plant running time + breakdown time).

Avcat: heavy kerosine fuel for aircraft based in marine carriers; distillation range 175 o -290°C.

Avgas: fuel for aircraft piston engines; distillation range 30°-200°C,

Avtag: Wide-cut fuel for aviation gas turbines; distillation range 30°-2000C.

Avtur: kerosine fuel for aviation gas turbines; distillation range 150°-250°C.

Axial flow: (compressor f turbine) design in which working gases pass through alternate series of rotor (rotating) and stator (fixed) blades which are mounted around a common axis; blades are aero­dynamically shaped to convert pressures arising from gas flow into rotary motion of the rotor; several stages of stator/rotor may be used.

Barrel: (petroleum) unit of volume measurement; 1 barrel (brl) = 42 US gal = 35 Imp gal (approx) = 159 litres (approx); common US abbreviation is bbl.

hdc: bottom dead centre; eg crank­shaft position at bottom of recipro­cating piston stroke; opposite to tdc (qv).

Bentone grease: lubricating grease with bentonite thickener.

Benzene: aromatic hydrocarbon with ring structure of six carbon atoms; b.pt 80°C; (cf benzine).

Benzine: obsolescent term for gasoline (petrol).

Benzole: commercial aromatic fraction from coal tar, mainly benzene and other aromatics.

Big end: (mech) term for crankshaft end of connecting rod in reciprocat­ing piston engine; eg big-end bear­ing.

Black smoke: (diesel engine) exhaust emission containing visible dark particles from incomplete com­bustion of fuel during (normal)

running. Block coefficient: (marine) the ratio

between the actual · underwater volume of a ship's hull and the volume of the circumscribing rectangular block.

bmep (brake mean effective pressure): constant pressure which would have to be applied throughout one stroke to a frictionless piston of same size f stroke as the actual piston of an engine, to obtain the same power as the latter gives per cycle; for diesel engines bmep is in the range 4-14 bars.

Boost: increase in pressure, eg of intake air into a piston engine by means of a mechanically-driven compressor or exhaust-driven turbo­charger; boost system may be single­or multi-stage (normally up to two stages).

Boundary lubrication: condition when two surfaces moving relative to one another are only partly separated by an oil film (or other lubricant).

Brake horsepower (bhp): measure of useful rate of working of an engine; 1 bhp = 33 000 ft-lb/min = 1.01387 metric horsepower (ch, cv, PK, PS) = 0.7457 brake kW.

Brake thermal efficiency: proportion of thermal energy in a fuel that is available for work outside an engine; equals indicated thermal efficiency less heat losses due to friction between moving parts.

Brayton (Joule) cycle: thermodynamic cycle on which the gas turbine principle is based; heat is supplied at essentially constant pressure; in practice, ideal thermodynamic pro­cesses are not realised because of component inefficiencies which reduce the work ratio (qv).

Breakdown maintenance: corrective action is taken only after plant has failed (wholly I partly); applicable particularly to readily-replaceable units, eg lamps.

BS&W: bottom settlings and water (or basic sediment and water); ie solids and aqueous solutions in an oil which separate out on standing or are removed more rapidly by centri­fuging.

Bund: wall of earth, concrete, etc,

185

built to confine any spillage of (par­ticularly) oil eg from storage tanks.

Burned air: (piston engine) air per engine cycle of which the oxygen is consumed in the process of com­bustion.

Calorific value: heat liberated by com­bustion of unit quantity of a substance under specified conditions (also gross and net calorific values); commonly expressed as calories per unit mass or volume; preferred Sl unit is the Joule (1 cal/g =4.1868 Jjg; 1 kcalfm3=4.1868 kJjm3 based on the international table calorie).

Capacity: of a piston engine is the product of the swept volume (capacity) of a single cylinder and the number of cylinders (ie for engines based on cylinders of the same dimensions); commonly expressed in UK/Europe as cmJ or litres, in North America as in3.

Carbon monoxide (CO): Toxic gas, of which a common source is the incomplete combustion of carbonaceous materials, eg, fossil fuels; its presence in exhaust emissiOns (eg from furnaces, internal-combustion engines) must be controlled by design of operating units and correct air /fuel ratio.

Carburettor: (engine) device for pro­viding a regulated flow of fuel to the induction system of an internal­combustion engine; (gasmaking) vessel ·in which hydrocarbon feed­stocks are cracked and mixed with water gas to make carburetted water gas (obsolescent in most areas where natural gas and more efficient gas­making processes are available).

Centrifugal flow: (compressor) design of rotating blades in a casing (roughly on the principle of the paddle wheel) used to compress fluids; eg gases in simple designs of gas turbines for which high pressure ratios are not required; also in water and steam turbines.

Cetane number: rating of ignition quality of a diesel fuel, indicating relative ease with which fuel will ignite when injected into combustion chamber of a compression-ignition engine; determined in a test engine and related to a scale from pure cetane (CN = 100) to alpha methyl naphthalene (CN = 0); cetene, C16H32 was formerly used in the place of cetane, C16H34 •

CFR engine: term for series of standard engines developed by the Co-ordinating Fuel Research Com­mittee (USA) for determination of engine behaviour of fuels.

Charge air: air which enters cylinder of a piston engine during a single gas exchange period, and remains in the cylinder at the end of the

186

exchange period (BS1798). Choke: (Ouid flow) venturi; choke

tube, eg in carburettor; restricted part of passageway which increases velocity of Ouid flow, accompanied by a local pressure drop (depression) just downstream of the choke.

Clearance volume: in a piston engine, the minimum volume to which the contents of the cylinder are com­pressed by piston movement.

Closed cycle: (gas turbine) heat from an external source is applied to a gas (the working fluid) which drives a power turbine; exhaust gas is cooled, recirculated to the com­pressor, and returned to the heat source and turbine etc; the gas may be air, helium, C02 etc.

Cloud point: temperature at which a cloud or haze starts to appear when a (previously dried) oil is cooled under specified conditions; cloud is usually caused by paraffin wax; quoted for automotive diesel fuels to indicate temperature at which line or filter blocking might occur (ASTM 02500; IP219).

Coil: (ignition) transforms relatively low voltage (eg 6-24 V from storage battery) to high voltage necessary to produce a spark across spark-plug electrodes; typically primary and secondary windings round an iron core, sealed in a container and insulated with oil etc.

Cold flow point: (aviation turbine fuels) temperature limit below which fuel cannot be relied on to flow from an aircraft tank (IP217).

Combustion chamber: (diesel) four basic types (qv) are (1) open com­bustion (direct injection); (2) swirl (indirect injection); (3) pre­combustion or antechamber (indirect injection); (4) air cell.

Combustion chamber: (general) space in which a combustible material (commonly an air-fuel mixture) is burned to produce required heat, pressure, etc; (piston engine) space in cylinder head and/or piston crown in which combustion is initiated at intervals; (gas turbine) usually static flame tube(s) system of fixed dimensions in which fuel is burned continuously during working cycle.

Component efficiency: (machine) the proportion of work put into a mechanical component of a system (eg engine) that is available for the next operation; low component efficiencies mean high losses (eg by friction, pressure or heat loss) and hence low overall efficiency of the system.

Compound rotary (CI) engine: design of rotary piston compression-ignition engine in which the four strokes of induction, compression, power, and

exhaust are performed in more than one unit; compression and power stages are separated to get optimum design of high- and low-pressure units.

Compression-ignition engine: a prime mover actuated by the expansion of gases produced by the spontaneous combustion of a fuel injected into air that has been preheated by com­pression.

Compression pressure: in a piston engine varies with crank angle, value depending on compression ratio and pressure of intake air (atmospheric or charged); maximum reached at tdc (without fuel firing); higher values after fuel is ignited (to ( +) 200 bars in highly charged diesel engines).

Compression ratio: of a piston engine is the ratio of (swept plus clearance) volumes to clearance volume; for spark ignition engines often in the range 5-10:1 (12:1 and over for high-performance automotive use); for diesel engines in the range 12-22:1 (cf pressure ratio).

Compressor: (general) a machine for raising the pressure of a fluid, eg a gas such as air; (gas turbine) unit that compresses the working fluid before heat is added and work is obtained by expanding the fluid (hot gases) through a turbine; g.t. com­pressors are usually axial-flow or centrifugal types.

Compressor surge: when the pressure or temperature on the delivery side of a centrifugal compressor rises above the range for which the diffuser is designed, at its particular speed, the flow is momentarily reversed in a pulse which reduces the delivery pressure; this pulsing effect continues until the conditions are rectified.

Convertible gas diesel engine: a gas engine (diesel) which can be converted (by modifying the con­struction) to operate solely on liquid fuel.

Convertible gas engine: a spark ignition gas engine that can be con­verted (after modification to its construction) to operate solely on liquid fuel as a compression-ignition engine.

Crosshead: a connection between piston-rod and connecting-rod which is supported in guides to counteract connecting-rod side thrust; used particularly in some large diesel engines to reduce side loading of piston against cylinder wall.

Crosshead engine: uses oscillating connecting-rod and reciprocating piston-rod to connect piston to crankshaft; engine may be single­or double-acting; (cf trunk-piston).

Cut-off size: common term for maxi-

mum particle size that can pass through a filter element; strictly true only for spherical particles. Typical ranges: engine air filters not over 10 JA-m; fuel filters 10-20 JA-m (for critical fuel injection equipment); pre-filter fuel strainers 75-40 JA-m.

Cycle: (gas turbine); (i) physical arrangement of system, eg closed­cycle or open-cycle (qv); (ii) the Brayton or Joule thermodynamic heat cycle on which operation of the gas turbine is based.

Cycle: (piston engine) term that describes (i) the frequency with which the operations of compres­sion, combustion, expansion, exhaust occur, ie 2-cycle or 4-cycle (the same as 2-stroke, 4-stroke); (ii) the type of thermodynamic heat cycle involved (Otto, Diesel, Rankine­qv).

Cyclic irregularity: caused by increases in piston speed during power stroke and lower speed during idling part of engine cycle; ratio of total variation in angular velocity at fly­wheel during one engine cycle to the mean angular velocity; expressed as (maximum minus mm1mum speed) divided by mean speed.

Dangerous atmosphere: environment that contains significant amounts of gas or vapour in concentrations that can be ignited (eg by a spark from friction, static or electrical equip­ment).

Decibel (db): unit of power level difference, given by 10 log W2 /W1

(W is a power); (1) used as a measure of response in electrical communications circuits and in electronic systems; (2) as a measure of acoustical (sound, noise) level.

Delay angle: interval, in degrees of crankshaft rotation, between start of lift of fuel-injection valve and the sudden rise in cylinder pressure that marks start of combustion in a compression-ignition engine; depends on ignition quality of fuel (IP41).

Derating: (engine) reduction in power, eg as ambient air pressure is reduced at increasing altitude, or as ambient air temperature rises; effect can be countered to some extent by turbo­charging (boosting).

Derv fuel: UK term for a gas oil suitable as fuel for high-speed compression-ignition engines (from: diesel engine road vehicle).

Detergent additives: compounds blended with lubricating oils to disperse products from deterioration of fuel and lubricant; especially those formed at high temperatures which can cause sticking or 'gumming' of mechanical parts (piston rings, valve guides, etc).

Detergent oil: lubricating oil for some internal combustion engines, often

blended with additives so that it will hold sludge particles in suspension, and so promote engine cleanliness.

llewaxing: process to remove wax from (particularly) petroleum pro­ducts such as lubricating oil; to improve flow characteristics at low temperatures.

Diesel engine: a compression-ignition engine (qv) based on the Diesel cycle; principle also credited to early work of Ackroyd-Stuart.

Diesel index (DI): parameter used to indicate ignition quality of diesel fuel, particularly when an engine test cannot be made to determine cetane number. DI = (aniline pt (°F) X API-gravity)/100.

Dispersant additive: compound blended with lubricating oil to keep products from fuel combustion in finely dispersed state, hence to minimise sludge formation and filter blocking; particularly in gasoline engines working in cold conditions.

Distributor: (ignition) mechanism for producing high-voltage electrical energy at required time or interval; eg at spark plugs in spark ignition engine; conventional distributors are limited to about 400 sparks/s using a cam/contact-breaker system.

l)ouble-acting: engine in which both ends of the cylinder contribute to the total work.

Drag load: (turbine) fluid flow through convergent passage produces in­creased kinetic (higher velocity) energy, with resultant drag (rear­ward force) on components.

nrop point: for petroleum products, temperature at which a drop of grease or other material first detaches itself from the main bulk when a sample is heated under specified conditions; indicates tem­perature at which a grease changes from semi-solid or solid to liquid state.

Dual-fuel engine: (1) a compression ignition engine that operates on liquid fuel alone, or on gas with injection of (a little) liquid fuel; (2) a gas turbine that can run on gaseous or liquid fuel. Fuels can be changed during running of either type of engine (automatically con­trolled, if required).

Effective swept volume: difference between clearance volume and cylinder volume when the last valve or port closes, and compression by piston movement starts.

Electronic ignition system: term for engine ignition system in which primary current is interrupted by a solid-state device (eg high-voltage transistor); mechanical contact breaker in distributor handles only a small control current, has longer life; system gives higher spark rate

(eg 800/s) than conventional distributor.

Engine sludge: insoluble products from lubricating oils and/ or fuels in internal - combustion engines, de­posited on parts other than com­bustion spaces; may contain water, hence potentially corrosive.

Engler viscosity: ratio of time of flow of fixed volume of oil . to that of water through an Engler viscometer; expressed as degrees; used com­mercially as measure of viscosity of petroleum products ( esp in continental Europe); (IP212).

EP lubricant: oil or grease containing extreme pressure additive; for use in high-load conditions, eg hypoid gears, cutting oils.

Explosive limits: compositions of mixtures of combustible gases f vapours and air (or oxygen) within which an explosion occurs when the mixture is ignited.

Extreme pressure additive: compound that contains element(s) (eg sulphur, chlorine, phosphorus) that react with metals to form organic films of high melting point; films help to prevent metal welding or seizure, scuffing, scoring of surfaces; used in EP lubricants.

Filter medium: that part of a filter unit on which the material to be removed is deposited; eg dust in an air-filter.

Fire bank: a bund made of earth. Fire point: lowest temperature at

which a material (eg a liquid fuel) gives sufficient vapour to form a continuously inflammable mixture with air; measured under specific test conditions (IP 35 & 36); fire and flash points may be specified in regulations for storage of fuels.

Fire wall: (1) a bund made of brick, concrete, metal, etc; (2) a wall used to protect operators when using safety devices.

Fixed choke: (carburettor) air /fuel mixture strength is determined by varying depression in a choke tube of fixed dimensions.

Flame tube: (gas turbine) space into which fuel is injected, and in which ignition, mixing with air, and initial combustion take place; part of com­bustion chamber, usually designed to localise maximum (very high) temperature of combustion.

Flammable: preferred term for inflammable, with which it is synonymous; capable of being ignited; (inflammable is used in some legal definitions).

Flammable limits: compositions of mixtures of gases/vapours and air (or oxygen) within which mixture can be ignited.

Flash point: lowest temperature at which a material (eg liquid fuel) gives sufficient vapour to form a

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momentarily flammable mixture with air; (1) 'closed' measured under specified conditions in a closed container (IP 33, 34, 113, 170); (2) 'open' measured in an open con­tainer (IP 35, 36); see fire point.

Huid lubrication: state when two surfaces moving relative to one another are completely separated by an oil or other film; same as hydro­dynamic lubrication.

l<'lywheel magneto: unit used eg on small gasoline engines to provide both ignition spark and current for lamps etc; a multi-pole permanent magnet rotor forms the engine fly­wheel; a backplate (stator) carries a pole assembly with appropriate windings for high and low voltage.

l•'ree power turbine: (gas) free-running turbine, mechanically separate, but driven by gas stream from gas generator turbine (qv); eg two-shaft turbine design in which available power takeoff is from shaft of free power turbine.

Frequency: reciprocal of the period of a function; cycle per unit time, 1 hertz (Hz) = 1 cycle per second (CPS, C/S).

Fuel injector: device through which fuel is injected into a combustion zone or pre-combustion area; also called nozzle, atomiser, sprayer, fuel valve.

Fuel injection: method of introducing fuel into a combustion process; eg (i) intermittently into air compressed in a diesel-engine cylinder, (ii) inter­mittently into the air-induction system of a spark ignition engine, (iii) continuously into the com­bustion chamber of a gas turbine, (iv) continuously into the combustion chamber of a boiler or furnace.

Gas-diesel engine: a compression­ignition engine that operates on gaseous fuel, but with injection of liquid fuel (of the order of 5%) to promote ignition only.

Gas engine: an engine that operates on gaseous fuel only (eg natural gas, manufactured gas, LPG).

Gas generator turbine: converts pressure and velocity of hot gases into shaft power, which is used to drive the compressor in a gas turbine system; exhaust gases are further used to drive a free power turbine, a freely rotating unit which provides shaft power output for external work.

Gas horsepower: energy available from a gas generator for conversion to shaft power by a free power turbine; energy is in form of a high velocity gas jet, and its value is of interest to free power turbine designers, rather than end-users.

Gasifier turbine: term for compressor­drive turbine in a gas turbine system.

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Gas exchange: (piston engine) period that starts with the opening of the exhaust orifice and ends at start of compression by the piston as the last orifice closes.

Gas oil: petroleum distillate that has viscosity and distillation range (d.r.) between kerosine and light lubricat­ing oil; d.r. 200°-340°C; used as fuel for high-speed diesel engines, as burner fuel for heating, and to enrich water gas.

Gasoline: refined petroleum distillate (b.pt 30°-220°C) used as fuel in spark-ignition internal combustion engines; also known (UK) as petrol or motor spirit.

Gas turbine: rotary engine that per­forms the functions of compression, heating, and expansion continuously in different parts of the unit. (1) open cycle type induces, compresses, and burns a fuel in atmospheric air, the working gases are then expanded and exhausted to atmosphere; (2) closed cycle type uses air or other gases, which are recirculated to the compressor from the working turbine, and are heated by an external source.

Gear oil: refined material for lubricat­ing gears; may contain extreme pressure (EP) additives.

Governor: device or system to regulate operating parameters (typically speed of an engine); may be mechanical, hydraulic, pneumatic, electrical.

Gross Calorific value: sum of heat produced by total combustion of a substance and heat of condensation of water vapour produced by the combustion.

Gross exhaust gas: (piston engine) total quantity of gases that pass to exhaust per cycle; (ie the sum of net net exhaust gas and scavenge air).

Gudgeon (wrist) pin: connects piston of reciprocating engine with little­end bearing of connecting rod; also termed piston pin.

Guide vanes: shaped passageway (eg blade, shutter, duct) which directs fluid flow to a required pattern; eg in induction system into first stage rotor of an axial flow compressor.

Gum: (petroleum) dark residue from evaporating volatile parts of certain motor fuels under specified con­ditions; existent gum is already present in the fuel (IP40); potential gum may be formed during long storage or by accelerated ageing (IP 131).

Hand: (of engine) when a horizontal engine is viewed from the cylinder end, the side shaft is on the right on a right-hand engine (on the left on a left-handed engine); handed engines are used in marine practice in pairs to drive propellers respectively clockwise and anti-

clockwise. Heavy duty oil: lubricating oil used

under severe conditions (eg high piston f crankcase temperatures) in some high-speed diesel and spark­ignited engines; usually contains additives to increase detergency and resistance to oxidation/ corrosion.

High torque rise: (engine) high-output unit, eg automotive diesel, designed to give better than conventional power /weight ratio; obtained by increasing turbocharging to give high torque back up; may require some basic redesign to take higher loadings.

Hypoid lubricant: an EP (extreme pressure) lubricant designed for use with hypoid gears, in which high interfacial pressures are developed.

Igniter: (gas turbine) provides initial firing of fuel charge for starting; usually needs to operate for short period only, using high-energy dis­charge from solid-state circuit; normally a surface discharge plug (qv).

Ignition accelerator (promoter): addi­tive that improves ignition quality of diesel fuel.

Ignition quality: rating of ease with which a diesel fuel ignites under operating conditions; normally ex­pressed in terms of cetane number or diesel index (IP 21, 41).

Ignition starting aid: (diesel) assists starting of compression-igmtwn engine from cold, eg by an electric­ally heated filament which warms and ignites a supply of diesel fuel to the inlet manifold, where it burns and warms the inlet air; (unlike an igniter or spark plug in a combus­tion chamber).

Ignition system: (electrical) method of igniting fuel-air mixture (or other combustible material), eg in a furn­ace or internal-combustion engine; includes hot wire, trembler coil, and jump spark methods.

IMechE: Institution of Mechanical Engineers (UK).

Impeller: rotating vane type of com­pressor; centrifugal compressor.

Indicated thermal efficiency: propor­tion of thermal energy in a fuel that is successfully transformed to mechanical energy in an engine, as calculated from an indicator diagram; is greater than brake thermal efficiency.

Indicated mean pressure: average pres­sure on an engine piston over one complete cycle, calculated from measurements of pressure by an indicator.

Indicated power: calculated from measurement, by an indicator, of pressures in an engine cylinder during a working cycle; power developed in the cylinder, expressed

as ihp (indicated horsepower) in British units.

Indicator (pressure): instrument that indicates actual pressures in air engine cylinder throughout the strokes of a working cycle.

Indicator diagram: graph of pressure against volume over one cycle in the cylinder of an internal combustion engine.

Induction: (engine) part of operating heat cycle during which working fluid is induced (inhaled, inspired, drawn-in) into the machine before compression; eg air /fuel in Otto cycle, air in Diesel or combustion gas turbine cycle.

Induction period: (oil) time before a break in stability occurs during testing of a product; eg accelerated ageing test of gasoline, or oxidation test of transformer or turbine oil; (engine) interval in a working cycle during which, eg air or air /fuel is drawn into the cylinder or combus­tion space.

Inhibitor: substance added to a material to prevent or retard un­desirable changes in quality or properties; of the material or in equipment in which the material is used; eg to prevent gum formation in stored fuels, colour change in lubricants, corrosion in turbines; a type of additive.

lntercooling: heat exchange, com­monly between fluid streams, used eg between two stages of compres­sion for gas turbine or of inlet air into piston engine to improve output by reducing volume (increasing mass) of fluid in system.

IP: Institute of Petroleum (UK); issues standard test procedures and recom­mendations; eg IP21 for diesel index.

Isochronous: (governing) control of a machine to operate at fixed speed regardless of load; eg engine-driven electrical generator.

Jerk pump: type of diesel fuel injec­tion pump based on design by Robert Bosch; a cam-operated plunger works at constant stroke in a fixed cylinder; fuel quantity delivered is controlled by rotation of the plunger and hence the relation of its profile to ports in the barrel.

Jet fuel: used in aviation jet engines; see Avcat, Avtag, Avtur.

Kerosine: light distillate petroleum fuel (distillation range 150° -280/300°C) used for combustion (heating), in aviation gas turbines, and in some industrial gas turbines; known in UK as 'paraffin', eg as used in domestic oil burners for heating or lamps.

Knocking: (engine) also pinking or pinging; detonation of fuel 1 air mixture in spark-ignition engine which results in rough running,

often with audible mechanical noise; can damage parts such as piston/ crankshaft bearings; see anti-knock value.

Knock-rating: related to octane number.

Lacquer: (petroleum) hard deposit similar to varnish and insoluble in oil; tends to form on pistons and cylinders of internal-combustion engines; (surface coating) natural or synthetic material usually applied as a fluid which dries to form a hard protective or decorative coating.

Lead: (element) symbol Pb, at.no. 82, soft grey metal, chemically resistant to attack, used, eg as radiation, acoustic screen; as alloys for many uses (bearings, solders); also useful as organic and inorganic compounds (eg anti-knock compounds).

Lead scavenger: (fuel) organic halide added to TEL and TML to help remove lead oxide from combustion space of gasoline engines; materials include ethylene dibromide or chlorine compounds;. lead is ex­hausted as the volatile halide (subject to anti-pollution control in some areas).

Lead susceptibility: (fuel) response of gasoline to addition of lead com­pounds (TEL, TML) in terms of increase in anti-knock quality.

Lime grease: lubricating grease with calcium (lime) based thickener.

Lithium grease: lubricating grease with lithium based thickener.

Little end: (mech) term for piston end of connecting rod in reciprocating piston engine; little-end bearing joins connecting rod to piston pin (gudgeon pin; wrist pin).

LNG (liquefied natural gas): essentially liquid methane, usually with some liquid ethane and heavier hydro­carbons; kept in liquid form for transport and storage under pressure and low temperature.

Loop scavenged: system of a two­stroke piston engine in which admis­sion and exhaust ports are placed in the lower part of the cylinder walls, either opposite each other or in two belts (one above the other).

LPG (liquefied petroleum gas): mixture of propane and butanes extracted from composite mixture of natural gas liquids (NGL); transported/ stored as liquid under pressure/ refrigeration; can be used as fuel for spark-ignition engines.

Lubricating grease: semi-solid lubri­cant, usually mixture of fluid and thickener such as a metallic soap of calcium, sodium, lithium, aluminium, or an organic clay complex (bento­nite); thickener type affects melting point, water resistance, other proper­ties of the grease.

Lubricating oil: petroleum oil suitable for lubricating applications, with or

without additives; distillation range 380° -500°C.

Maximum mean piston speed: mps at maximum crankshaft speed of an engine; calculated from mmps= stroke X2X crankshaft speed (rev/min).

Machine oil: general purpose lubricant for shaft bearings and similar applications.

Magneto: (ignition) device for produc­ing a spark, eg at spark plug of gasoline engine; basically a magnet system, primary and secondary circuit windings, contact breaker (to interrupt primary circuit), and high tension distributor; needs no external source of electrical energy (cf coil).

Maintenance: a service to assist in the most economical and efficient run­ning of plant, machinery, etc., and the optimum production of goods or services (eg power); maintenance types include breakdown, preventive, planned.

MAPI: Machinery and Allied Products Institute, Chicago, Ill., USA.

Marine engine oil: for lubricating bearings and other contact surfaces of reciprocating marine steam engines; usually contain blown oils or other additives to give good emulsification.

Mechanical efficiency: of a heat engine is the ratio of its brake/indicated powers, mean effective pressures, specific fuel consumptions, and thermal efficiencies; mechanical efficiency tends to decrease as engine rotational speed rises.

Mechanical (solid) injection: forces fuel to an injector (eg in a diesel engine) by a high-pressure variable­delivery pump; amount and frequency of fuel delivery are controlled by pump design.

Microcrystalline wax: extracted from some petroleum residues; has finer crystal structure and is usually more opaque than paraffin wax; hardness from soft and plastic to hard and brittle, colour white to dark brown; plastic form has been wrongly termed 'amorphous wax'.

'micron': term for micrometre (10-6m = 1 fLm); micron is not recommended for standard (international) usage; approx 39.37 micro-inch.

Mineral oil: derived from mineral sources; eg petroleum, oil shale, tar sands, coal.

Mixtute response curve: for aviation gasoline, indicates degree of knock­suppression by enriching air-fuel mixture, and consequent possible gain in output from increasing supercharge pressure; relationship between knock-limited engine mean effective pressure or power output, and air-fuel ratio or sfc.

Motor oil: refined lubricating oil for internal-combustion engines; often

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with additives. Motor spirit: term for gasoline; petrol. Naphtha: a petroleum distillate that

boils in the gasoline range (80°-180°C); used as a fuel in industrial gas turbines, and as a feedstock in making gasoline.

Naturally aspirated: a diesel engine which operates without a turbo­charger (term also used in the case of a two-stroke engine which has an engine-driven blower).

Net calorific value: gross calorific value minus heat released by condensation of water vapour produced by the combustion.

Net exhaust gas: (piston engine) gas present during an expansion stroke which passes to exhaust during the gas exchange period.

Nitrogen oxides (NOx): (fuel combus­tion) mixture of oxides of nitrogen, of particular importance in exhaust emissions from internal combustion engines; subject to pollution control legislation; production tends to in­crease as combustion temperature/ pressure rises, but depends also on engine design etc.

Noise: (engine) arises from two distinct sources; (mechanical) from gears and driving trains for auxiliaries, valve gear, pumps; (combustion) associated with changes in cylinder pressures, transmitted by piston, crankshaft, etc. to main engine structure to cause vibrations; also gas flow pulsations, eg from valve or port characteristics; see work noise.

Octane number: measure of anti-knock quality of a gasoline; %-volume of iso-octane in a mixture of iso-octane (ON=IOO) and n-pentane (ON=O) which has the same knock charac­teristics as the gasoline under test; higher octane numbers indicate higher knock resistance (IP 42, 44, 119, 126, 150, 172); ON can be increased by additives.

Open cycle: (gas turbine) takes atmospheric air as working fluid, which is compressed, heated by injection and combustion of a fuel, used to drive a power turbine, and eventually exhausted back to atmosphere.

Opposed-cylinder: engine with pairs of cylinders in line on opposite sides of a crankshaft to which the respective pistons are connected; a common design is the horizontally-opposed (flat) engine.

Opposed-piston: engine based on an open-ended cylinder in which two pistons travel in opposite directions (ie piston heads face each other); compression and expansion of cycle gases occur in the varying space between the pistons.

Oil engine: a compression-ignition

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engine (qv); similar to the diesel engine.

Open combustion chamber: (diesel) fuel is injected directly into the combustion space, which is normally a cavity in the crown of the piston; advantages include simplicity, high thermal efficiency (low fuel con­sumption), easy starting.

Paraffin: one of the paraffin series of hydrocarbons; also a term for kerosine.

Paraffin scale (white scale): similar to paraffin wax, but less refined and containing more oil.

Paraffin wax: solid relatively crystal­line material extracted from petroleum, shale oil, etc; refined grade has low oil content, is white, fairly translucent, and free from taste or odour (used eg for 'waxed paper').

Performance number (PN): rating given to fuels (esp aviation gaso­lines) that have octane numbers over 100; roughly the maximum knock-free power obtainable from the gasoline expressed as flo of that from iso-octane (ON= 100); (IP 42, 119, 150).

Petrol: UK term for gasoline; motor spirit.

Petroleum: naturally-occurring mineral oil, usually liquid mixture of hydro­carbons, though modern usage in­cludes gaseous and solid materials; raw material from which gasoline, kerosine, lubricating oils, fuel oils, paraffin wax, bitumen, etc are obtained.

Petroleum spirit: refined distillate that boils in the gasoline range.

Pick-up: (ignition) ferrite device with input and output coils actuated .by a rotating armature drum with insert ferrite rods (one per cylinder); system produces intermittent high­voltage output as does a conven­tional coil ignition distributor; rotor arm is attached to armature drum.

Pinking (pinging): light knocking in a gasoline engine; occurrence depends on anti-knock value of fuel and engine characteristics, esp compres­sion ratio.

Planned maintenance: optimum use of maintenance work to get maximum economy and life of plant/equip­ment; based on work study, produc­tion planning/control, cost control.

Power kerosene: has suitable anti­knock value for use as fuel in spark­ignition engines; distillation range 150° -260°C; also known as vaporis­ing oil.

Pre-combustion chamber: (diesel) sep­arate chamber connected to cylinder by a small throat or several holes; fuel is injected into the chamber, where combustion starts; similar in characteristics to swirl chamber (qv).

Pre-ignition: uncontrolled ignition in a spark-ignition engine that occurs before the normal spark; caused by hot-spots such as overheated plugs or incandescent carbon deposits.

Pressure ratio: (compressor) ratio of compressor delivery pressure to compressor entry pressure; value depends on design (eg centrifugal or axial flow) and number of stages involved; theoretical efficiency of gas turbine depends on compressor pressure ratio.

Preventive maintenance: (general) carried out at first sign of fault or potential fault in equipment/plant etc; (scheduled) routine periodic (calendar or running-time) work, eg

lubrication, overhauls, replacement of parts.

R/e ratio: (rotary piston engine) ratio of distance (R) of one apex of a rotor from its centre to the eccentri­city (e) described by the centre of the rotor in a planetary machine (in which rotor and eccentric are the moving parts); R/e ratio affects engine characteristics.

Recuperator: heat exchanger used esp in a regenerative cycle (eg in a gas turbine); walls that separate hot and cold fluids are stationary (eg a tubed cross-flow or counterflow ex­changer).

Redwood viscosity: time of flow (seconds) of fixed volume of oil through a Redwood viscometer; commercially-used scale of viscosity esp for petroleum products in UK; (IP70).

Reference fuel: engine fuel of known octane or cetane number used as a standard for the engine testing of fuels.

Regenerator: heat exchanger; for gas turbine system design involves a moving wall between hot and cold fluids, eg a rotating drum or disc of which the heat transfer material moves alternately between hot and cold fluid streams.

Reheat: heat exchange, commonly to boost heat in a fluid stream to improve working characteristics; eg

exhaust gas from one turbine is heated by burning additional fuel in a separate combustion chamber be­fore passing to a second turbine.

Residual gas: (pistion engine) gas re­maining in a cylinder from the previous cycle; together with the charge air it makes up the cylinder content during the compression stroke.

Resistor coil: term for a spark-ignition coil designed to work at less than available supply voltage (eg 7.5V from a 12V system); full voltage is applied (by cutting out a resistor in the low-tension circuit) for initial engine starting.

Rotor: (compressor I turbine) rotating system of blades; in an axial flow design are mounted around a rotat­ing (driven) shaft, often in a series of stages alternating with stator blades.

Rotor: (electrical ignition) rotating part within spark-ignition system; eg (1) rotating winding or (usually) rotating magnet in magneto; (2) rotating contact in an ignition distributor.

Rotor: (piston) rotating member of, eg, a rotary piston engine in which it moves within a housing to produce compression, expansion, exhaust, and induction functions; housing contains inlet/exhaust valves or ports, and ignition system; rotor may have combustion chamber recessed in its sides.

Rotary piston engine: internal com­bustion engine in which the centre of gravity of the power output member moves unilaterally in a circular path; types include single rotation, planetary, and rotating piston machines; the NSU-Wankel design is a planetary type, ported, four-stroke Otto cycle unit.

Rotary piston machines: pumps (from 1588) and steam engines (from 1799) have been practicable for a long time; attempts have been made since 1900 to realise the Otto 4-stroke cycle in this form; the Wankel design succeeded in 1954.

Running on: continued firing of an internal-combustion engine after the ignition system has been switched off; caused by hot spots as in pre­ignition.

SAE: Society of Automotive Engineers (USA).

Saybolt viscosity: time of flow (seconds) of fixed volume of oil through a Saybolt viscometer; commercial measure of viscosity of petroleum products (ASTM 088-56), esp in USA.

Scavenge air: air that passes through a piston engine from inlet to exhaust during a single gas exchange period (ie the difference between total air and charge air).

Series 3 (lubricating oil): an oil that has passed the reference test for superior lubricants (Series III) on Caterpillar 1-0 and 1-G engines.

Service factor: ratio of actual running time of a unit or operation to calendar time; measure of con­tinuity of an operation.

Single-acting: piston engine in which the working cycle is performed only at one end of the cylinder.

Sludge: deposit of solids or solid/ liquid mixture, usually an un­desirable material; see acid, engine, tank sludge.

Smoke: (engine) visible material in

exhaust emissiOns caused by eg incomplete combustion of fuel or blow-by of lubricating oil (eg past piston rings or valve guides); see black smoke, white smoke.

Smoke point: maximum flame height (mm) at which a kerosine will burn in a lamp under specified conditions without producing smoke (IP 57).

Sound pressure level: in decibels of a sound is 20 log (ratio of pressure of the sound to a reference pressure); the reference ·pressure is eg 0.0002 microbar (20 micro­Newton). Sound pressure ratios are not always proportional to square root of corresponding power ratios and should not be expressed in decibels (though they commonly are, in practice).

Spark: (ignition) electrical discharge used to ignite eg fuel-air mixture in an internal combustion engine; typical energy order O.OlJ, potential 5-15 kV or up to 25 kV.

Spark ignition: (engine) internal com­bustion engine in which the working fluid (eg air-fuel mixture) is ignited by a high-voltage spark; (system) method of producing required spark discharge, including magneto, battery-coil, electronic systems.

Spark plug: (or sparking plug) device to produce spark of required characteristics within an internal combustion engine; (1) usually across an open gap between electrodes for a spark-ignition (Otto cycle) engine; (2) as an igniter in a gas turbine combustion chamber (usually a surface discharge type).

Specific fuel consumption (sfc): the weight of fuel consumed in unit time in an engine, divided by the brake power output (eg expressed in kg/kW h; lb/bhp h); sfc of a particular engine depends on operating conditions, load, speed.

Spontaneous (autogenous) ignition temperature: point at which mixture of flammable vapour and air will just ignite, tested under specified conditions (ASTM 0286).

Stator: (compressor /turbine) fixed blades that direct fluid flow to impinge on the movable blades of a rotor; in a power turbine each row of rotating blades (rotor) is pre­ceded by a stator; in a compressor, the first row of blades is a rotor, onto which the working fluid is directed by guide vanes.

Stator: (electrical) fixed part of a rotor I stator system as used in electric motors, generators; (ignition) typically the windings and pole pieces of a high-tension magneto, between which the magnet system (rotor) revolves.

Stoichiometric: quantity corresponding to chemical reaction values; eg in

combustion, the m1mmum amount of air (or oxygen) required for com­plete oxidation of a hydrocarbon fuel to carbon dioxide and water vapour.

Strapping: method of measuring cir­cumference of a tank with a steel strap or tape, to determine its liquid capacity.

Surface discharge plug: an igniter for some spark-ignition engines and with high-energy systems for gas turbine starting; differs from con­ventional spark plug in that electrodes between which discharge occurs are separated by a semi­conducting insulator material.

Swept volume: change in cylinder volume resulting from piston move­ment (for a single piston per cylinder = product of cross-section area of cylinder and full piston stroke; differs for Wankel rotor engine (qv)).

Swirl chamber: (diesel) combustion design in which at least half the charge is compressed into a separate chamber connected to the cylinder by a fairly small throat; fuel is injected into the chamber; advantages include very high air utilisation, higher speeds than open chamber (but lower thermal efficiency and poorer starting).

Tank sludge: collects at the bottom of tanks in which petroleum products (crude oils, fuels, residues) are stored; usually contains water; see BS&W.

TEL (tetraethyl lead): organic com­pound of lead used as an anti-knock additive in gasolines.

tdc: top dead centre, commonly crank­shaft position when piston in a reciprocating engine is at top of its stroke in the cylinder (corresponds to maximum compression); often used as a reference point for ef? ignition, fuel injection or valve timing.

'thou': term commonly used for one thousandth of an inch (0.001 in = 0.0254 mm); see micron.

Thrust load: (turbine) fluid flow through divergent passage converts kinetic to pressure energy, produces thrust (forward force) on com­ponents.

Timing: (engine) the efficient operation of piston engines dependg on optimum timing of various (usually inter-related) functions; eg ignition timing (of spark in a s.i. Otto cycler engine); of valve gear or other control of induction 1 exhaust periods; of fuel injection in a compression-ignition engine; timings may be controlled in relation to pressure, speed, load, etc.

'Templug': hardened steel screwed plug used to measure local tern-

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perature in eg a piston, into which it is screwed; after heating, measure­ment of the relaxation of hardness indicates the temperature to which the device has been subjected (devised by Shell International Petroleum).

TML (tetramethyllead): organic com­pound of lead used as an anti-knock additive in gasolines.

Torque back up: (engine) increase in torque at maximum torque, when compared with torque at maximum speed; obtained, eg in a diesel engine by turbocharging; see high torque rise.

Total air: air that passes through the inlet orifice of a piston engine per cycle.

Toxic atmosphere: any atmosphere in which there are concentrations of gas or vapour enough to make it potentially toxic; is important in industrial operations that involve toxic products; in confined spaces such as storage tanks.

Trunk-piston: design that uses only a connecting rod between piston and crankshaft in single-acting types; (cf crosshead engine).

Turbine: rotary machine driven by a working fluid, eg water, steam, hot gases.

Turbine oil: highly refined petroleum oil used to lubricate steam and other turbines; usually contains additives.

Turbocharger: compressor driven by engine exhaust and used to boost inlet air pressure, particularly for diesel engines; operates at typical pressure ratios up to 3 .5: 1 and used with diesel engines in range 400-1500 kW; unit is essentially a gas turbine in which the engine replaces the combustion chamber.

Turnaround (turnround): period in which a process or mechanical unit is inspected, overhauled, repaired.

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Uniftow: two-stroke piston engine system with inlet ports in cylinder which are uncovered just before the bottom of the piston stroke; exhaust valve(s) in cylinder head are opened before the inlet ports are uncovered, and closed before they are covered.

Vapour lock: stoppage of liquid flow in a line, caused by accumulation of excess vapour, eg by local over­heating of fuel in a fuel line; esp in gasoline engines.

Vapour pressure: pressure due to the vapour from a substance enclosed in a confined space; increases with rise in temperature; a liquid boils when its vapour pressure equals the ambient pressure (eg atmospheric pressure).

Variable choke: (car.burettor) constant vacuum system in which depression in choke tube remains approxi­mately constant, but size of jet and choke are varied.

Variable compression ratio: to limit cylinder pressure in a diesel engine to optimum value, a two-part piston can be used; the height of the piston crown is varied by oil pressure acting in a space between the two parts of the unit; mainly for specialised (military) use up to 1971.

Venturi: see choke. Viscosity: property of a liquid that

makes it offer resistance to move­ment or flow; (dynamic) expressed as N sjm2; (kinematic) expressed as m2 Is, more commonly as centistokes (leSt = lmm2fs), or commercially for petroleum fuels etc as Redwood and Saybolt (seconds) or Engler (degrees); Engler X 29 = Redwood = Saybolt X 0.85.

Viscosity index (VI): arbitrary scale used to indicate changes of viscosity with temperature in lubricating oils etc (IP 73).

Viscosity index improver: additive used to improve VI of a lubricating oil.

Volatility: degree to which a substance tends to vaporise or evaporate; increases relatively with rise in temperature.

Wankel engine: a rotary piston engine (qv) first produced 1954 as a single rotation machine to original design of Dr. Felix Wankel; later versions have been simpler planetary rotation types with stationary housing.

Water bottoms: water that accumulates at (or is sometimes added to) the bottom of a liquid in a storage tank; eg for petroleum oils.

Water finder: instrument used to find the level of water bottoms in an oil storage tank.

Watt (W): unit of power (= 1 I/s); 1 metric horsepower (ch, cv, PS, PK) = 0. 735499 kW; 1 British horsepower (hp) = 0.7457 kW.

White smoke: (diesel engine) occasional appearance of white vapour in exhaust emission, usually at start-up or cold engine operation; caused by presence of unburnt fuel in exhaust gas.

White spirit: refined petroleum distillate with distillation range (150°-200°C) within gasoline limits.

Work noise: (engine) created by expansion and contraction of gases in process of converting heat energy into mechanical effort.

Work ratio: (engine) ratio of net power output to total power pro­duced; ie power developed in a cylinder or turbine less mechanical and heat losses in the system; ratio tends to be higher for Otto and Diesel cycles than for gas turbine, which is particularly sensitive to component efficiencies and pressure losses.

Wrist pin: (mech) gudgeon pin; piston pin.