TEP4 1 1 5 / 4 1 2 0 Term odynam ikk Kap 9: Gas Power Systems - PDF document

TEP4 1 1 5 / 4 1 2 0 Term odynam ikk Kap 9: Gas Power Systems Stempelmotorer Olav Bolland Begreper: Fig. 9.1/2, side 374 4 Stroke Engine Process • *Intake Stroke • Compression Stroke • Power Stroke (Expansion) • Exhaust Stroke * For Spark Ignition engines, intake is of an air/fuel mixture. For Diesel engines, intake is air only. motorer.ppt

Work closed/open systems First law for an open system (steady-state): First law for a closed system: dU             Q W m h m h 0 Q W U U 1 2 2 1 dt Relating heat to entropy: Relating heat to entropy: 2 2 2 2         Q T dS dU pdV Q T dS 1 1 1 1     and and T dS dU PdV T dS dH Vdp   T dS dU PdV       H U pV dU dH pdV Vdp 2 2 2       2 2 Q T dS dU pdV      Q dH V dp 1 1 1 1 1 2 2 2               U U pdV W U U Q m dh V dp 2 1 2 1 1 1 1 2 2               m h ( h ) V dp W m h ( h ) 0 W pdV 2 1 1 2 1 1 2       W V dp 1 motorer.ppt Air Standard Analysis The following assumptions are made: • Air, an Ideal Gas, is the working fluid • Combustion is replaced with Heat Addition (see Chap 13 for details) • No exhaust and intake strokes – constant volume heat rejection • All processes are internally reversible For Cold-Air Standard, Specific Heats are also assumed constant motorer.ppt

Otto Cycle *Cycle Analysis: W m   12 u u 1 2 W m   34 u u 3 4 Q m   23 u u 3 2 Fig. 9.3, page 376 4 Internally Reversible Processes: Q m   41 • Isentropic Compression u u 1 4 • Constant Volume Heat Addition • Isentropic Expansion * Sign Conventions (Work in • Constant Volume Heat Rejection negative, etc.) are sometimes changed for cycle applications motorer.ppt Nikolaus August Otto, 1876 Diesel Cycles *Cycle Analysis: W m   12 u u 1 2 W m   34 u u 3 4 W   m   23 p v v Fig. 9.5, page 406 2 3 2 4 Internally Reversible Processes: Q m   23 h h • Isentropic Compression 3 2 • Constant Pressure Heat Addition • Isentropic Expansion Q • Constant Volume Heat Rejection m   41 u u 1 4 motorer.ppt Rudolf Christian Karl Diesel, 1893

Ottomotor - prinsipp motorer.ppt Otto 4-takts motor motorer.ppt

Totakts-motor motorer.ppt http://science.howstuffworks.com/two-stroke2.htm Diesel vs Otto • Diesel engines, with higher compression ratios (20: 1 for a typical diesel vs. 8: 1 for a typical gasoline engine), tend to be heavier than an equivalent gasoline engine • Diesel engines, because of the high compression ratio, tend to have lower maximum RPM ranges than gasoline engines. This makes diesel engines high torque rather than high horsepower. • Diesel engines must be fuel injected, and in the past fuel injection was expensive and less reliable • Diesel engines tend to produce more smoke and "smell funny" • Diesel engines are harder to start in cold weather, and if they contain glow plugs, diesel engines can require you to wait before starting the engine so the glow plugs can heat up • Diesel engines are much noisier and tend to vibrate motorer.ppt

Hva er bensin/diesel ? C m H n bensin (  C 9 H 20 ), diesel (  C 14 H 30 ), paraffin (  C 12 ) flytende ved omgivelsestilstand Greit å huske 1 liter bensin = 9.7  10 kWh varmeverdi (35 MJ) 1 liter diesel = 11.4  11 kWh varmeverdi (41 MJ) 1 Sm 3 naturgass  10 kWh varmeverdi Sm 3 er vanlig mengdemål for naturgass (trykk 1.013 bar, 15 °C) Nm 3 er ellers vanlig mengdemål for gasser (trykk 1.013 bar, 0 °C) motorer.ppt Verdens største dieselmotor Wärtsila-Sulzer RTA96-C Total engine weight: 2300 tons Height: 13.4m Max power: 108920 hp at 102 rpm 81 MW 25.5 knop = 47.2 Km/t Emma Maersk 81 MW from RTA96-C 30 MW from 5*Caterpillar 397m long, >1400 containers motorer.ppt 157000 tonnes (deadweight)

V-motor (V8) V16 Rekkemotor (R4)

Stirling motor - prinsipp motorer.ppt Stirling motor - prinsipp motorer.ppt