Chapter 20, Problem 5P

Q78 A four cylinder, four-stroke Petrol engine has a compression ratio of 6 to 1. A test on this engine gave the following results; Net brake load = 20 kg, effective brake arm = 0.5 m, indicated mep=6*105 N/m², engine speed 2400 rpm, fuel consumption = 10 kg/h, Calorific value of the fuel = 44000kj/kg, Cylinder bore 86 mm, engine stroke-100mm. ข่าวล Calculate: the mechanical efficiency, ⑥the brake thermal efficiency the relative efficiency assuming the engine works on the Constant volume cycle and that 8-1.4 forair ⑧The brake mean effective pressure. Answers 1 88.4%, 48/5-35 × 105 N/m² 1 و و

Hom Work عماد داود عبور (35) Q18 The Fiat car has a four strok engine of 1089 C.C capacity.It develops maximum power 32kw at 5000 r.p.m. The volumetric efficiency at this speed is 75% and the air-fuel ratio 13:1, At peak power the theoretical air speed at the choke is 120 m/sec. The coefficient of discharge for the venturi is 0.85 and that of the main petrol jet is 0.66. An allowance should be made for the emulsion tube, the diameter of which can be taken as (1/2.5) of the choke diameter. the Petrol surface is 6 mm blow the choke at this engine condition. Calculate the size of a suitable choke (D) and main jet (d).The specific gravity of Petrol is 0.75 andthe Latmospheric pressure 1.03 bar and temperature 27°c. [D=23.2mm,d=1.296mm]

Q8: A test carried out on a single cylinder, two. Stroke oil engine gave the following data: Cylinder bore = 200 mm, stroke 250mm, engine speed = 300 rpm, net brake torque 500N.m indicated mean effective Pressure = 4.9*105 N/m², fuel consumption = 5kg/min, Cooling water. rate of flow = 0.0666 kg/sec, temperature rise of cooling water-55k, specific heat capacity of water =4.1868 kj/kg.k. calculate the mechanical efficiency, the specific fuel consumption, and draw up an energy balance in kw. Answers [@ 81.6, 0.318 kg/kW.hr, © Qtotal = 61.1kw,- Qb.p = 15.7 Kw₂ & Cooling water = 15.35kw,Q Exhaust = 30.05 kw]