THE INTERNAL COMBUSTION ENGINE - PERFORMANCE

Question 1. An engine delivers a brake power of 200 kW. What is the output torque of the engine if the engine speed is 3000 revs min^-1?

Question 2. From the p-V diagram for a single cylinder four stroke internal combustion engine, the work done per power cycle is 500 Nm. The engine runs at 4000 revs min^-1 producing a torque at the output shaft of 25 Nm. If the piston diameter and stroke length are 200 mm and 800 mm respectively, calculate:
(a) the indicated power

(b) the indicated mean effective pressure

(c) the mechanical efficiency of the engine.

Question 3. A double cylinder four stroke internal combustion engine has cylinders of 100 mm diameter and stroke length 250 mm. When the engine runs at 4000 revs min^-1, the indicated mean effective pressure is 300 kN m^-2 and the mechanical efficiency is 70%, calculate:
(a) the indicated power

(b) the brake power

(c) the brake mean effective pressure

(d) the torque at the output shaft.

Question 4. The output torque and speed of a single cylinder four stroke engine are measured as 20 Nm and 3000 revs min^-1. The piston diameter and stroke length are 200 mm and 400 mm respectively. If the mechanical efficiency of the engine is quoted as 40%, the indicated thermal efficiency as 50%, and the calorific value of the fuel is 40 000 kJ kg^-1, calculate:

(a) the rate of fuel consumption

(b) the indicated mean effective pressure

(c) the brake mean effective pressure

(d) the indicated specific fuel consumption

(e) the brake specific fuel consumption.