Derating of Recip By ISO standard 3046
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This document summarizes information from an international standard on reciprocating internal combustion engines. It discusses standard reference conditions, definitions of various types of engine power and fuel consumption, how to account for auxiliaries and ambient conditions, heat balances, and efficiency calculations. Performance curves are shown for a Wärtsilä 18V46 engine depicting variations in electrical output, specific fuel oil consumption, and derating according to ambient temperature and altitude.
Derating of Recip By ISO standard 3046
- 1. Wärtsilä Seminar Presented by Med Seghair / BDM Wärtsilä Finland Oy
- 2. Wärtsilä Seminar International Standard ISO 3046/1…7 (1995) Reciprocating internal combustion engines - performance Part 1: Standard reference conditions and declarations of power, fuel and lubricating oil consumption and test method Part 3: Test measurements Part 4: Speed governing Part 5: Torsional vibrations Part 6: Over-speed protection Part 7: Codes for engine power
- 3. Wärtsilä Seminar International Standard ISO 3046/1 (1995) STANDARD REFERENCE CONDITIONS: - Total barometric pressure : 100 kPa. (1,0 bar) - Air temperature: 298 K (25 ºC) - Relative humidity: 30 % - Charge Air coolant temperature: 298 K (25 ºC) note! Relative humidity of 30% @temp 298 K corresponds to water vapour of 1kPa. Hence the corresponding dry barometric pressure is 99 kPa
- 4. Wärtsilä Seminar Power: - Declared power “rated power/ output” SI in kilowatt Metric horse power (hp) = 0,736 kW Engine horse power (HP) = 0,746 kW Note! When stating the Output, the revolution, the ambient conditions and load should be mentioned!
- 5. Wärtsilä Seminar Type of power?: - Declared power - Indicated power - Brake power /shaft - Continuous power - Overload power - Fuel stop power - ISO power - ISO standard power - Service power - Service standard power - Power adjustment - Power correction
- 6. Wärtsilä Seminar Auxiliaries?: It is necessary to distinguish those auxiliaries which affect the final shaft output - dependent auxiliary (engine-driven) - independent auxiliary (separately-driven) - non-essential auxiliary (far auxiliary)
- 7. Wärtsilä Seminar Fuel oil consumption?: =is the quantity of fuel consumed by an engine per unit of time at a stated power, under stated ambient conditions, and full load + lower heating values of the fuel + tolerance + auxiliary + power factor + measurement point (Shaft, generators) note! in general the used SI Unit = g/kWh
- 8. Wärtsilä Seminar Lubricating oil consumption?: = is “the quantity of lubricating oil consumed by an engine per unit of time at a stated power, and load” + the oil discarded during an engine oil change shall not be included into the lube oil declaration + a stated period of running shall be declared note! in general the used SI Unit = litre/ or g/kWh Note! First 500 Opr-hours is standard period test
- 9. Wärtsilä Seminar Turkey Calorific value of fuels?: liquid fuel engines “any declared specific fuel consumption of a liquid fuel engine shall be related to a reference distillate type fuel of lower calorific value of 42 700 kJ/kg.” gas engines “any declared specific fuel consumption of a gas engine shall be related to a stated lower calorific value of the gas. The type of the gas shall be declared” The (MN) Methane number is concedered to be >80
- 10. Wärtsilä Seminar water sulfur ash vol (%) mass (%) mass (%) 0,3 3 0,01
- 11. Wärtsilä Seminar LHV vs Sulfur vs SFOC 198,71 205,11 201,63 200,27 203,47 38600 38800 39000 39200 39400 39600 39800 40000 40200 40400 40600 40800 1 2 3 4 5 Sulfur (mass %) LHV(kJ/kg) 194,00 196,00 198,00 200,00 202,00 204,00 206,00 SFOC(g/kWeh)tol.0 LHV (kJ/kg) SFOC (g/kWh) water density ash vol (%) kg/m3 mass (%) 0,3 995 0,01
- 12. Wärtsilä Seminar Heat balance?: fuel input Fi = B * Q where: B = gross fuel oil consumption in (kg/s) Q = net calorific value in (kJ/kg) Cooling water Pcool = m * c * dt where: m = the massflow of the water (kg/s) c = thermal conductivity for water (4,18 kJ/kgK) dt= temperature rise (K)
- 13. Wärtsilä Seminar Exhaust gases Pexh. = m * c * dt where: m = the mass-flow of the exhaust gas in (kg/s) c = thermal conductivity for gases (1,045 kJ/kgK) dt= temperature difference of gases (K) The “dt” is the exhaust gas temp. minus the ambient temperature. Power output P = 1,31 * (D*D) * S * Na * Z * Pme where: D = piston diameter (m) S = stroke (m) Z = number of cylinders Pme = calculated mean effective pressure (bar) Na = working cycle per minute (rpm/2)
- 14. Wärtsilä Seminar Efficiency?: In the diesel engine, injected fuel is not completely changed to mechanical energy. The energy changed to useful work is named as total efficiency (ne) ne = (P/be)*Q Where: P = output , be = s.f.o.c and Q = fuel net H.V the easiest way to calculated the efficiency is (Efficiency) = Output / Input measured in (%)
- 15. Wärtsilä Seminar 0 10 20 30 40 50 60 70 80 0 5 10 15 20 25 30 MeanTemp, °C M. Relative humidity, %
- 16. Wärtsilä Seminar 0 10 20 30 40 50 60 70 80 Avr Jan Feb March April May June July Aug Sep Oct Nov Dec M. Relative humidity, % Mean Temp, °C
- 17. Wärtsilä Seminar Operating data? In case the engine power will be utilised under more difficult conditions than those mentioned or stated in the sales documents. Otherwise, the engine manufacturer can give advice about the correct output reduction. As a guideline additional reduction may be calculated as follows: Reduction factors = -(a + b + c) where: a = 0,5 % for every ºC on CA exceeds the I.S.O ref. conditions b = 1 % for every 100 m level above I.S. O ref. conditions c = 0,4 % for every ºC on CW exceeds the I.S.O ref. conditions
- 18. Wärtsilä Seminar Turkey Wärtsilä 18V46/ Performance (kWe) @ 100 m.a.s.l (m) 17 024 7 000 8 000 9 000 10 000 11 000 12 000 13 000 14 000 15 000 16 000 17 000 18 000 10 15 20 25 30 35 40 Ambient Temperature, °C GeneratorOutputinkWe Derating according to ISO 3064 Derating according to Wartsilä
- 19. Wärtsilä Seminar 18V46`s SFOC, g/kWh vs Engine load, % 201,9 201,0 204,0 210,0 195,0 197,0 199,0 201,0 203,0 205,0 207,0 209,0 100,0 90,0 75,0 55,0 Engine load,% SFOC,g/kWh LHV = 40 047 kJ/kg and Ambient T= 25 °C
- 20. Wärtsilä Seminar 18V46`s SFOC, g/kWh VS Ambient temp, °C at 100 a.s.l (m) 201,9 202,5 203,2 203,5 201,0 201,5 202,0 202,5 203,0 203,5 204,0 25 30 35 40 Ambient temp, °C SFOC,g/kWh SFOC, g/kWh L.H.V= 40 047 kJ/kg