Again, it depends upon the application.....once a ship is started from a "cold iron" state, it rarely, if ever, cools down until it is dry docked or laid up.....an emergency or harbor diesel is started initially......and that smaller engine supplies lights, and warmth via it's cooling/jacket water......then other auxiliaries are started beginning with air compressors.....then one of the ships service generators is started (bigger engine) and it's cooling system can be cross connected to the main engines....and because we burned residual fuels like Bunker C we also lit off a small boiler to supply steam or hot water (in some cases hot "thermal oil") in order to heat the fuel, fuel pumps, and fuel lines via trace lines......once the engine, and fuel was warm....we could then start a main propulsion engine as needed......

most of the larger ships engines inject high pressure (400 Bar) "starting air" into the cylinders via a starting air distributor system.....thus rotating the engine to starting speed.....

the only engine that may possibly get cranked for any length of time is the small emergency engine......and we very rarely found any need to use ether!!!

But back to the topic at hand.....length of stroke has nothing to do with the need for a glow plug......and I have seen the punk ignited engines as well.....

SB

__________________

Diesels:
'85 300D, "Max, Blue Benz", 155K, 27.0 MPG
'84 190D 2.2, "Eva, Brown Benz", 142K, 40.2 MPG
'77 240D (parts car)
'67 Eicher ES 202 Tractor "Otto" (2cyl, Air Cooled, 30HP)
Gassers:
'94 Ford F-150, "Henry", 170K (300 Six) 17.5 MPG
'85 190E 2.3, 148K....Parts Car
'58 Dodge W300M Powerwagon (Flat Fenders) Less than 10 MPG

Please note that I never said that the little ball was a source of ignition.....I said....

"So when the engine is cold, the glow plug heats the little ball (initially), the fuel is squirted onto the ball, and vaporized.....and combustion occurs when the compression rises to it's ignition point.....after the engine is running the heat of combustion maintains the little ball temperature....."

....try dripping a a few drops of diesel onto a hot soldering iron.....it will produce a white smoke like vapor....this is what I was referring to when I said vaporized.....this fuel vapor is easily ignited......

I had not intended to begin an in depth discussion of the process....I was doing my best to simplify the operation of the pre-combustion chamber, to a point where most could understand what was going on inside of the pre-combustion chamber......and the fact that the initial heat supplied by the glow plug was maintained by the heat of combustion.....

SB

__________________

Diesels:
'85 300D, "Max, Blue Benz", 155K, 27.0 MPG
'84 190D 2.2, "Eva, Brown Benz", 142K, 40.2 MPG
'77 240D (parts car)
'67 Eicher ES 202 Tractor "Otto" (2cyl, Air Cooled, 30HP)
Gassers:
'94 Ford F-150, "Henry", 170K (300 Six) 17.5 MPG
'85 190E 2.3, 148K....Parts Car
'58 Dodge W300M Powerwagon (Flat Fenders) Less than 10 MPG

http://en.wikipedia.org/wiki/Diesel_engine#Fuel_injection_in_diesel_engines

__________________
Scott C.

2006 E320 CDI (120k miles)
FOR SALE: 1998 E300 Turbo Diesel - Black w/Tan Leather - Euro delivery (236k miles)

The discussion was limited to starting the engine.

The glow plug cannot heat the little ball sufficiently in 15 seconds to allow it to reach any temperature that is even close to the point where the fuel would vaporize on contact. The only way this could occur if if the glow plug tip was in direct contact with the steel ball for the entire 15 second period...........only in this case would your argument have merit.

If you're speaking about a running engine, then it's a completely different discussion.

From the previously posted wikipedia article:

"An indirect injection diesel engine delivers fuel into a chamber off the combustion chamber, called a prechamber, where combustion begins and then spreads into the main combustion chamber, assisted by turbulence created in the chamber. This system allows smoother, quieter running, and because combustion is assisted by turbulence, injector pressures can be lower, which in the days of mechanical injection systems allowed high-speed running suitable for road vehicles (typically up to speed of around 4,000 rpm). The prechamber had the disadvantage of increasing heat loss to the engine's cooling system and restricting the combustion burn, which reduced the efficiency by between 5-10% in comparison to a direct injection engine, and nearly all require some form of cold-start device such as glow plugs."

The implication is that direct injection diesels start easier without glowplugs.
Are there direct injection engines WITH glowplugs or indirect injection engines WITHOUT glowplugs?

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

Most of the newer light duty truck engines, such as the Cummins and the Ford are DI engines. They do have glow plugs, however...........again..........because of the demands of the public.

As mentioned above, the Cummins can probably start without them under most conditions.

I don't know of any IDI engine without glow plugs.

The 5.9L and 6.7L Cummins have an intake heater mounted on the manifold inlet, no glowplugs.

Interesting. Didn't the earlier Cummins in the Dodge trucks have glow plugs at one time...........???

............failing memory.........

Nope. From 1989-2007, only an intake heater.

How's that device work? Induction heating of the air in some fashion?

It has two heating elements and the computer controls whether one or both grids are energized and for how long. It can also stay running after the engine is started. Works exactly like a hair drier.

The one I have got up to 875*f in 5 seconds when I tested it.

I have a W115 300D intake that I welded a flange onto specifically to mount this heater. I'm going to test fit it next weekend.

Attached Thumbnails

 

The '96 Dodge Cummins that I once owned had an air intake heater....no glowplugs.......nener have seen a Cummins in a Dodge that did....but again maybe the older ones......

SB

__________________

Diesels:
'85 300D, "Max, Blue Benz", 155K, 27.0 MPG
'84 190D 2.2, "Eva, Brown Benz", 142K, 40.2 MPG
'77 240D (parts car)
'67 Eicher ES 202 Tractor "Otto" (2cyl, Air Cooled, 30HP)
Gassers:
'94 Ford F-150, "Henry", 170K (300 Six) 17.5 MPG
'85 190E 2.3, 148K....Parts Car
'58 Dodge W300M Powerwagon (Flat Fenders) Less than 10 MPG

Yes, the length of a stroke directly affects your compression ratio! A higher compression ratio, at static, will rsult in a hot initial start because of the increase in cylinder pressure, lessening your need for glow plugs. All diesels do benefit from them however.

The length of the stroke has nothing to do with the compression ratio.

The compression ratio is the ratio between the cylinder volume at BDC and the cylinder volume at TDC. A longer stroke simply provides for more volume. The static compression ratio is determined by the shape and coutour of the cylinder head.

Last Saturday morning the temp was 19°F in the lean-to part of my barn where I store my tractor. She's a 1978 model John Deere 2040 (3cyl DI - no glow, no heated intake air). For grins I thought I'd see if she would fire up and I'll be damned! She rolled over sort of slow for about 2 revolutions and lit right off.

Considering that her battery looks sort of small (like it came out of a Neon!) I was pretty impressed.

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Never a dull moment at Berry Hill Farm.