©2005 Melior, Inc. ____________________________________________________________________________________
The engine is the power plant of a vehicle. Automotive engines have gone through tremendous changes since the automobile was first introduced in the 1880s, but all combustion engines still have three requirements that must be met to do their job of providing power – air, fuel, and ignition. The mixture of air and fuel must be compressed inside the engine in order to make it highly combustible and get the most out of the energy contained in the fuel mixture. Since the mixture is ignited within the engine, automobile power plants are called internal combustion engines. Most can be further classified as reciprocating piston engines, since pistons move up and down within cylinders to provide power. This up-and-down motion is converted into turning motion by the crankshaft.
Some of the main engine components This course will provide an introduction to automotive engines and engine performance. Subjects covered will include: • Major engine components • Engine classifications • The four stroke cycle and other engine design operations • Engine construction • Air-fuel systems • Ignition systems • Cooling and lubrication systems • Exhaust systems, computer systems, and emissions • Engine performance and diagnostic strategies • Engine diagnostic tools • Basic diagnostic testing
Upon completion of this course, technicians should understand and be able to apply and demonstrate their knowledge of: • Engine classifications and components • Engine operations and construction • Engine systems including cooling, lubrication, computer, and fuel and ignition systems • Exhaust and emissions systems • Engine performance and diagnostic strategies • Basic engine diagnostic testing and test equipment Using the Job Sheets As you proceed through this module, on some pages you will find links to job sheets. Each link will open a window with a printable procedure or job sheet that contains hands-on lab activities based on the NATEF standards related to the content you are studying. When you come upon a procedure or job sheet link, you can click on it to access the material and print the job sheet for completion in the shop. See your
©2005 Melior, Inc.
Introduction to Engine Performance – Study Guide
_____________________________________________________________________________________________ instructor for guidance in completing the job sheets. Some jobs sheets will require supplemental materials such as a vehicle service manual, equipment manual, or other references. Your instructor may prefer you to print the entire set of job sheets and assign them when appropriate, or your instructor may provide you with the printed job sheets to complete. You can view and print any or all of job sheets for this course by clicking on the “Job Sheets” link.
Basic Engine Parts and Operation
A small engine, such as one found in a lawn mower, usually contains only one cylinder and piston. Automotive engines use a number of cylinders to produce sufficient power to drive the wheels, but operate much like a small engine in many ways. Let’s look at one cylinder of an engine to see how the main parts work together. Engine Block The block, highlighted here in grey, is a heavy metal casting, usually cast iron or aluminum, which holds the lower parts of the engine together and in place. The block assembly consists of the block, crankshaft, connecting rods, pistons, and other components, and is referred to as the bottom end. The block may also house the camshaft, oil pump, and other parts. The block is machined with passages for oil circulation called oil galleries (not shown) and for coolant circulation called water jackets.
Cylinders The cylinders are round holes or...