Chapter 1: Internal Combustion Engines

What is the difference between a two-stroke and four-stroke engine?

A two-stroke cycle engine is an engine that utilizes two strokes to complete one operating cycle of the engine (intake/compression and power/exhaust) whereas a four-stroke cycle engine utilizes four strokes to complete one operating cycle (intake, compression, power, and exhaust).

What are the two methods of cooling an engine?

Air-cooled (engine circulates air around the cylinder block and cylinder head) and liquid-cooled (engine circulates coolant through cavities in the cylinder block and cylinder head)

What is the difference between an internal and external combustion engine?

An internal combustion engine is an engine that generates heat energy from the combustion of a fuel inside the engine (ex. gasoline engine), whereas external combustion engines are engines that generate heat energy from the combustion of a fuel outside of the engine (ex. steam engine).

What were Otto's and Diesel's contributions to engine development?

Nikolaus Otto developed the first successful gasoline engine, and he introduced the four-stroke cycle engine. Rudolf Diesel developed the diesel engine.

Small engines are rated to how much horsepower and how are they further classified?

Small engines are generally rated up to 25 horsepower and then further classified by ignition, number of strokes, cylinder design, shaft orientation, and cooling system.

What are the two methods of fuel ignition?

Spark and compression

What are the three cylinder orientations?

Vertical, horizontal, and slant

What is the formula for work?

Work = force x distance

What is the formula for horsepower?

-HP = work / (time x 33,000) -HP = (torque x RPM) / 5252

What is torque and what is the formula for torque?

-Torque is a force acting on a perpendicular radial distance from a point of rotation. -Torque = force x radius

What was James Watt's contribution to engine development?

James Watt contributed the engine development by (1) incorporating an outside condenser to increase efficiency (2) creating a valve system in order for pistons to be pushed by steam in both directions (double acting steam engine) (3) converting the reciprocating motion of the piston into rotary motion to expand usefulness (4) developing an engine speed control device (governor) (5) discovering that a full cylinder of steam was not needed to produce a full stroke of the piston in a steam engine.

Describe potential and kinetic energy.

Potential energy is stored energy a body has due to its position, chemical state, or condition, and kinetic energy is the energy of motion (which is technically released potential energy).

What is the formula for pressure?

Pressure = force / area

What is the throw of an engine?

The throw is the measurement on a crankshaft from the centerline of the crankshaft to the centerline of the connecting rod (offset).