THE ENGINEER EXPLAINS

Welcome to The Engineer Explains website.

This is a forum for young people, their parents and teachers to learn about engineering.  The principal audience is young people (and their parents and teachers) interested in pursuing an engineering career.  "The Engineer" will answer engineering questions of a general nature (such as how things work, career path, etc.).  The Engineer will not do any detailed analysis, nor give any advice that would require a Professional Engineering License.  If you require any such advice, please contact a PE (Professional Engineer).

*World-renowned Civil Engineer Vincent T. H. Chu author of various Civil Engineering books will also answer more technical questions, which are put forth on a peer-to-peer basis by other engineers.  For more information about Mr. Chu see "About Us."

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• To ask The Engineer a question please click on "Ask The Engineer" in the left sidebar.
• To ask Mr. Chu a question or read his articles please click on "Ask Vincent T. H. CHU" in the left sidebar.
• To see the questions that have been asked of The Engineer and answered, click on "Questions asked of the Engineer."
• For the Engineer's musings and some humor, click on "Musings of The Engineer (& humor)."
• Please take a look at the rest of the navigation links in the left sidebar.
• We would like to extend an invitation to you to write an article(s) for this website - see "Do you want to write an article for The Engineer Explains?" in the left sidebar.

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FOUR-STROKE ENGINE OVERVIEW
(SPARKPLUG .VS. GLOW PLUG)

Are glow plugs in a diesel engine for the same purpose as the sparkplugs in a gasoline engine?

The short answer is no.  The reason I give the short answer is that I have observed persons read similar articles to this one and come away with an affirmative answer.

GASOLINE ENGINE (sparkplug)

In a four-stroke gasoline engine the fuel and air is mixed somewhere before the intake valves.  This mixture is pulled into the engine cylinder when the intake valves open and the piston starts down away from the cylinder head for the intake-stroke.  At the bottom of the intake-stroke, the intake valves close and the piston travels back towards the head, compressing the air fuel mixture (compression-stroke).  At an appropriate point near the top of the piston travel (Top Dead Center – TDC of the compression-stroke), a high voltage pulse is applied to the center electrode of the sparkplug causing a spark to jump the gap to the outer electrode.  This spark ignites the air fuel mixture, releasing the chemical energy of the fuel as heat and a large volume of gas, driving the piston back away from the cylinder head for the power-stroke.  At the end of the power-stroke the exhaust valves open and the piston travels back towards the head expelling the combustion gases for the exhaust-stroke.  At the end of the exhaust-stroke, the exhaust valves close and the process starts all over.  In a gasoline engine, the sparkplug ignites the air fuel mixture at the beginning of every power stroke (similarly in a two-stroke gasoline engine).

DIESEL ENGINE (glow plug)

In a four-stroke diesel engine, the air enters the piston through the intake valves devoid of fuel.  As the piston moves away from the . . .

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a.k.a. YO ENGINEER a.k.a. HEY-ENGINEER a.k.a. YO-ENGINEER a.k.a. THE ENGINEER EXPLAINED
a.k.a. Ask The Engineer a.k.a. Ask an Engineer a.k.a. questions about engineering a.k.a. how things work

The Engineer thinks that Ms. Ordunez has done a great job with these lesson books. Ms. Ordunez designed and wrote these for homeschooling. However, they may be of use to teachers in a formal classroom setting also.