Question

1-1. List five differences between SI engines and CI engines. 1-2. A four-stroke cycle engine mayor may not have a pressure boost (supercharger, tur in the intake system. Why must a two-stroke cycle engine always have an intake 1-3. List two advantages of a two-stroke cycle engine over a four-stroke cycle engine. List two advantages of a four-stroke cycle engine over a two-stroke cycle engine. 1-4. (a) Why do most very small engines operate on a two-stroke cycle? (b) Why do most very large engines operate on a two-stroke cycle? (c) Why do most automobile engines cngnis on a lostrosk oelele (d Why would it be desirable to operate engines on a two-stroke 1-5. A single-cylinder vertical atmospheric engine with a 1.2 m bore and a piston of 2700 kg mass is used to lift a weight. Pressure in the cylinder after combustion and cooling is 22 kPa, while ambient pressure is 98 kPa. Assume piston motion is frictionless. Calculate: (a) Mass which can be lifted if the vacuum is at the top of the cylinder and the piston moves up. [kgl (b) Mass which can be lifted if the vacuum is at the bottom of the cylinder and the piston moves down. [kg) 1-6. An early atmospheric engine has a single horizontal cylinder with a 3.2-ft bore, a 9.0-ft stroke, and no clearance volume. After a charge of gunpowder is set off in the open cylinder, the conditions in the cylinder are ambient pressure and a tempcrature of 540°F. The piston is now locked in position and the end of the cylinder is closed. After cooling to ambient temperature, the piston is unlocked and allowed to move. The power stroke is at constant temperature and lasts until pressure equilibrium is obtained. &鄹and the cylinder is air and piston motion is frictionless. Ambient condi- 14.7 psia. tions are Calculate: (a) Possible lifting forcc at start of power stroke. [Ibe] (b) Length of effective power stroke. [ft] (c) Cylinder volume at end of power stroke. 3] 1-7. Two automobile have the same total displacement volume and the same total power produced within the cylinders List the possible advantages of: (a) A V6 over a straight six (b) A V8 over a V6 (c) A V6 over a V8. (d) An opposed cylinder four over a straight four. (e) An in-line six over an in-line four. 1-8. A nine cylinder, four-stroke cycle, radial SI engine operates at 900 RPM Calculate: (a) How often ignition occurs, in degrees of engine rotation. (b) How many power strokes per revolution (c) How many power strokes per second.

Answer 1

Answer 2

1-7. Two automobile engines have the same total displacement volume and the same total power produced within the cylinders. List the possible advantages of: (a) A V6 over a straight six. (b) A V8 over a V6. (c) A V6 over a V8. (d) An opposed cylinder four over a straight four. (e) An in-line six over an in-line four.