Why no glow plugs?

[Neil & Pat LeKander]

You observation is quite correct. The primary reason for glow plugs (or
heated intake grids) being used on small consumer diesels is because of the
market where they are offered for sale. Can you really see the little ole'
soccer mom trying to start the family Mercedes via spraying ether down the
intake? But for the truck driver, bus driver, or equipment operator it is
all in a days work.

There are also technical reasons for the difference. Most small diesels
utilize a different type combustion chamber design than do the large
commercial truck engines. They are equipped with a pre-combustion chamber
located in the head or top of piston, when so equipped the amount of heat
required to raise the temperature to the degree that will aid cold starting
in minimal and can be provided by the battery system in the form of glow
plugs or heated grid. In contrast to heat a very large combustion chamber
such as used in 9-14 liter diesel would be immense, certainly well beyond
what could be provided by a battery. Note, that virtually all-large diesel
engines come with block heaters, which apply external heat to the combustion
chamber area of the engine. This of course serves the same purpose as does
the glow plugs or heated intake grid but has a 110 VAC electric source to
provide the required energy. On my own DD 6V92 I can assure you that all of
the above is correct and works quite well.

I did read another response to your inquiry in which it was stated that
trucks have glow plugs but buses do not. I am quite certain that is not the
case as truck and bus engines are generally identical excepting for the
cooling system and a few other components.

Neil
Author, "The RVer's Ultimate Survival Guide"
http://www.rvsafetyinfo.com
author@...

Can someone tell me why domestic car and truck diesels have glow
plugs and large diesels i.e. buses do not? Just a thought that occured
to me as I was plugging in my two buses and Mercedes diesel today.
I've had four buses and none of them have had glow plugs. They just
start after a few turns of the starter whether air or electric.
However, every diesel Mercedes, Chevy, etc I've owned and have seen
has glow plugs. What gives?