Question

1. (35 pts) Specific fuel consumption rate curves are given for three different engines: A, B and C. Power and Torque curves for Engine 'B' are also given at Page 3. Please answer the following questions for Engine 'B'. a) (5 pts) Find the power and torque when it runs at the engine rpm of minimum specific fuel consumption rate. b) (5 pts) Find the torque and specific fuel consumption rate when it runs at the engine rpm of maximum power. c) (5 pts) Find the power and specific fuel consumption rate when it runs at the engine rpm of maximum torque. d) (10 pts) The following driving profile is given for Engine 'B'. Please calculate the total consumed fuel in [kg] for the given driving profile. 2 hours at maximum power - 1.5 hours at maximum torque - 3 hours at minimum specific fuel consumption - 4 hours at 2500 rpm - 1 hour at 3500 rpm. e) (5 pts) Calculate the packaging volume needed for the fuel tank if the fuel density is 800[kg/m). f) (5 pts) Please explain how you performed calculations at Part d) and e) (steps for the calculations) with your own words (this part of question aims to avoid plagiarism) SFC curves for Engines 0.60 0.55 Engine A Engine B - Engine C 0.50 0.45 Specific Fuel Consumption (kg/kW-hr) 0.40 0.35 0.30 0.25 0.20 1000 2000 3000 7000 4000 5000 6000 Engine speed (rpm)

Answer 1

Solution Sfc - Specific fuel consumption Po torque PS Power engine speed (rpm) (Q) (5J)minimten at Na 5000 rpm At 5000 rpm , T= 420 Nm 218 kw. (b) Power (P) is monimum at N= 2498 opm at N= 2498 rpm Pa 380 Nm. sha= 0.25 +0.30 = 0.275 kg/kwah c) m (T) mare at N = 5600 rpm . At this spead 245kW. sfc = 0.265 kg/kwho

(d) (1/2 hr at mare Sla = 0.295 byl kw hr. Porns 285 kw. sfc- 2. ng kylhor. ng Power ing 285 0-2757 ing = 78.375 kg/h. In 2hr, fuel used, my = 2428-375 = 156.25 kg 1.5hr at Tman. at Tman , P=.245kW. and sf = 0.200 kg/kw-ho. sfc 245 In 1.5hr, 0-260x245 = 63.7 kg/hr. s of fuel = 63.7x15 = 95.55 kg. Thor at N= 2500rpm. at sfc = 0.34 kg/kwhy p=gokw. . mossy fuel = uA (0.34890) = 122:4kw

(iv) Ihr at 3500 rpm At 3500 rpm we have sfc = 0.28 bylk w-hr and p = 138kW, ng shaxP In Its, fuel used 1x(0-28*138) = 38.64 kg. - Total mass - 156.75+ 6317 + 122.4+ 38.64 = 4949.98 kg . Packaging volume va v 4949.98 6.18 m3.