Why do some diesels require glow plugs and others don't?

[cabover4us]

Have very little experience in this subject, but my choice of tractor was reflected on by my older neighbor Francis. I don't care if it was -20 Francis would go out and turn the key of his John Deere 855 count 5 seconds, barely spin and fire off....
My 855, because of his, starts just a bit harder but not much. And of course I failed to mention he had a Curtis Cab with heat, and I, three layers and coveralls....
He plowed and I used rear snowblower, many a storm together on my private road...RIP Francis

 

[Creamer]

I didn't read all the answers, but in MY mind the answer is fairly simple.

ASSUMEING both diesels are in good shape, with good compression, for cold starts,

Direct Injection = faster starts without glow plugs

Indirect direction = needs glow plugs...

I have plenty of both and this IS the way it always works out.

I HATE GLOW PLUGS!!

Years ago, even the small Kubota's were DI and they started instantly, with out glow plugs!!

ALL of my real tractors start WITH OUT having to glow any plugs, they are all DI!

THANK the EPA for glow plugs, that's why the mfg's went to them...I remember when it all got started down that path and I didn't like it any more then than I do now!

Did I mention that I HATE glow plugs??

SR

BTW, the "grid heater" in the Cummins, is there more to keep the cold smoke away than it is to get the DI Cummins started! I have one of those too...

I agree Rob but I think it has more to do with fuel atomization and compression - the compression to heat the air and the better the fuel is atomized the easier it ignites. Direct injection atomizes it better. I remember growing up we could start our IHs when it was cold but the Deeres (20 and 30 series) would crank and crank and we finally built a heated building for them. Then Deere (40 series) switched to the same fuel pump the IHs were using and their problem was solved.

 

[Agvg]

The Perkins AD3-152 in MF135 is an excellent design when it comes to cold start, -20C is almost the same as 20C, but Perkins have made lot of not so good engines models to.

 

[Creamer]

The Perkins AD3-152 in MF135 is an excellent design when it comes to cold start, -20C is almost the same as 20C, but Perkins have made lot of not so good engines models to.

Agree with the latter - the Perkins 3.9L in my Versatile is as cold blooded as I have ever seen an engine. 40 F and it will not start without starting fluid.

 

[slivo]

The heat comes from compressing the air. Fuel has a cooling effect and liquids aren't compressible. On older tractors that the throttle also cut off fuel, you can get a quicker start by cranking with the fuel off and then adding fuel after it's spinning.

Here is my equipment list and starting issues:

-John Deere 98' 690E 44,000# excavator - no GP's and only use starting fluid after it runs out of fuel or the battery is nearly dead. O/W starts in any weather in a click. 24 volt, turbo
-JD 710 loader backhoe 1996 - ditto above, similiar 6 cyl engine. 24 volt starts on first turn. turbo
-JD 550G dozer, 4 cylinder, turbo, 15,000 hours, starts on first click even if snow is a foot deep on the hood. 12 volt. Perhaps a shot of starting fluid if its very cold and just changed the fuel filter.
-Ford 655c loader backhoe. 4 cyl, 12v, no turbo, has a button on dash for a single glow plug in the air intake. Starts always on 3rd crank unless really cold and battery weak.Keep starting fluid handy with this well used dog.
-2 Perkins Lincoln 400 amp DC welder gensets. 900 hours and 4500 hours. 4cyl with glow plug button on dash. Have not needed it, but have not tryed to start them in Wisconsin weather.
-Toro commercial flail mower - 3 cylinder Kubota. Starts a bit faster with the glow button. O/W no issue.
-Mercedes diesel, 1998? drove me crazy with suction side leaks on the diesel fuel system. Need to plug it in each night when under 40 degrees F! Finally epoxied a coffee pot warming plate to the oil pan and it got a bit better. Impossible issues with all internal electricals. Junked it.

Friend with a giant Cummins pickup truck. Engine sounds like a 1890's rig with external pushrods. Should be a noise law against them. Many glow plugs. POS in my opinion. The John Deere engines run like sewing machines and if ever it sounded like that crap Cummins, it would go right into the shop for a rebuild. All you Cummins lovers, fine, different design and long life. But why would you accept all that noise? Put a Deere engine in them. Want some respectful noise get a Harley.

-Did have a Ford 550 flatbed with the international 7.3 always started, didnt seem to have a glow plug wait
-Ford 2004 "new" diesel design. Piece of crap. Smoked and finally started on fire and burned to the ground one night about 4 hours after I parked it at the shop. Neighbors called when the tanks blew. Police could not even identify it or find a vin #. RIP
-Best truck is my ford f-150, 2009 with the small gas v-8. Gets the same mileage as my Jeep Patriot. Probably good for 300,000 miles. Quieter and smoother than my Dodge grand caravans.

 

[art]

I didn't read all the answers, but in MY mind the answer is fairly simp

Direct Injection = faster starts without glow plugs

Indirect direction = needs glow plugs..


Years ago, even the small Kubota's were DI and they started instantly, with out glow plugs!!



THANK the EPA for glow plugs, that's why the mfg's went to them...I remember when it all got started down that path and I didn't like it any more then than I do now!

Did I mention that I HATE glow plugs??

SR

BTW, the "grid heater" in the Cummins, is there more to keep the cold smoke away than it is to get the DI Cummins started! I have one of those too...

We sell both! I don't remember Kubota using direct injection even going back to the late 70's but they both have their benefits, indirect injection is cleaner although if you like to make more horsepower then it was designed with it is not as easy to soup up!!! Cold starting there have always been better and worse! Thats of both kinds!!! I do have my favorites from the farm tractors as far as cold starters but some people are okay either way!

 

[jimmysisson]

My Ford 2120 starts instantly down to ~40*, five secs of glow below that. Block heater below 10*. Friend's 1910 about five years older needs glow plugs all summer long, 15 seconds. Both Shibaura, and his has half the hours.
Jim

 

[Sawyer Rob]

We sell both! I don't remember Kubota using direct injection even going back to the late 70's

I "think" the last DI Kubota I had was a L2850?

All of my tinker toy tractors now, are IDI

SR

 

[oleman]

Combustion chamber design. The most common industrial diesel ever produced was a Detroit Diesel 2 stroke, so far as I know the first 6-71, sold in 1938 was a non glow plug engine. And so was the last new one sold in the US in 2000. The compression ration was around 17-19:1. I had a little ISUZU 1.8 LTR diesel with a 22:1 ratio it had glow plugs.
Various companies have had different ways to cold start their engines. The older Japanese diesels tended to like glow plugs because of the very low cold start capability. The International Harvester diesel in our utility was produced in Germany the the IH Neuss plant. It has well designed combustion chambers and starts well down to about 20F after that it requires starting fluid. I have never required in Texas USA. It has a 16:1 compression ratio. Cat and Deere have used pony gas motors to spin the diesels up for starting. International had a diesel that also had the ability to start on gas and then switch to diesel. Generally speaking the engines with GLOW PLUGS will start well below 0F if all the glowplug electrics are together and the injection system is good.
The new family of computer controlled engines are also good starters in cold weather when they are in good condition.

 

[finn1]

An IDI engine will always have glow plugs because of the heat transfer characteristics inherent to the design concept. The fuel is injected into the prechamber, but the throttling of the chamber throats and large surface areas suck a lot of thermal energy from the compressed air and transfer that heat to the water jacket.

That heat transfer is also why IDI engines have such high static compression ratios (21:1, or more is typical).

Remember, these are compression ignition engines.

Many modern direct injection engines have gone to glow plugs for one primary reason, that being customer satisfaction.

This trend probably started with light duty pickups, many of which found their way into suburban households where rough starts and white smoke emissions were simply not tolerable.

Industrial engines followed suit, as clean starts and no white smoke became marketing issues for generators and equipment housed near or with farm animals.

I worked in Diesel engine development for many years and still remember a field complaint from lt late 70s from a farmer from Minnesota who had a tractor that filled his barn with white smoke and made his cows sick.

We released a service kit with higher compression pistons for that product, although that resulted in higher black smoke and a resultant slight power decrease.

Some modern engines still use a manifold grid heater for customer satisfaction, but they aren't as effective as glow plugs, all other things being equal. Similarly, manifold flame heaters work, but it's a fine line between heating the intake air and consuming the oxygen necessary to ignite the diesel fuel injected into the combustion chamber.

Higher cetane fuel is arguably the best starting aid, but consumers don't always have that option.

European fuel cetane was about 50 min, compared to a 42 min here, if I recall correctly.