Will Tier 4 lead to gas tractors again?

[joefromga]

I suspect you don't see this in today's engines because gassers can inherently turn more rpms (not 100% sure why)

Because of the longer stroke of the diesels.

 

[Ilikeurtractor]

Would a shorter stroke diesel be able to achieve gas engine equivalent RPMS?

 

[joefromga]

I would imagine that it won't have the same compression ability with a shorter stroke because the compression stroke is what heats the air and causes the ignition.

I have a feeling that engineers have tried to do this for years. If it's possible there's probably a trade off that's less desirable. Mainly, less torque.

In tractors you need long life and torque as opposed to race cars. The longer stroke is an advantage of leverage so to make that go faster you trade in rpms.

Gearing generally has been the solution. Drive a VW diesel and you'll see.

 

[buickanddeere]

Would a shorter stroke diesel be able to achieve gas engine equivalent RPMS?

Diesels can not rev like a gasser due to cam timing and valve size.
A high rpm engine needs a long duration cam which doesn't bother a gasoline engine which uses a spark plug for ignition .
A diesel needs a short duration cam to obtain maximum combustion chamber pressure and thus temperature to ignite the mist of diesel .
The diesel with the short duration cam makes good low rpm torque but can't breath and runs out of power somewhere around 2200-2800rpm. Then again so does a gas farm tractor with the same diesel cam . In fact the gasser will make more power per cubic inch.
It is easier to obtain 16 to 1 compression with a small bore/long stroke engine vs a large bore/short stroke engine of the same displacement.
Another point is the long stroke , small bore engine can not use as large of valves as the large bore/short engine . Once again limited breathing due to the small valves also limiting airflow .
Higher rpm diesels are possible with variable cam timing and glow plugs. Cylinder pressure is raised for higher pressure and temperature when the cam is advanced. High rpm breathing is improved when the cam timing is retarded. Even if the combustion chamber is not warm enough for ignition a spray of raw diesel onto a red hot glow plug will start combustion. Still doesn't have the power band and area under the curve that a variable cam gasser has.

 

[sbct]

I personally believe the consumer panic about the clean "tier 4" diesel engines will blow over and be a total non issue. Although I dont own a "tier 4" equipped tractor, I do drive a "tier 4" Ram 2500 with a Cummins every day and I have put a ton of miles on without a single problem. When it says add DEF I add my DEF, when it wants to regen to clean the particulate filter it regens, and I just keep driving along towing my travel trailer or whatever else I got back there without any issues. I understand everyones concern but I feel that with time these engines will prove to be just as reliable and stout as the pre-smog/tier 4 engines were. And there is no arguing the fact that I can now have a picnic behind my diesel tail pipe and would argue that the air coming out of it may in fact be cleaner that what floats around Los Angeles everyday!!

 

[3930dave]

I personally believe the consumer panic about the clean "tier 4" diesel engines will blow over and be a total non issue. Although I dont own a "tier 4" equipped tractor, I do drive a "tier 4" Ram 2500 with a Cummins every day and I have put a ton of miles on without a single problem. When it says add DEF I add my DEF, when it wants to regen to clean the particulate filter it regens, and I just keep driving along towing my travel trailer or whatever else I got back there without any issues. I understand everyones concern but I feel that with time these engines will prove to be just as reliable and stout as the pre-smog/tier 4 engines were. And there is no arguing the fact that I can now have a picnic behind my diesel tail pipe and would argue that the air coming out of it may in fact be cleaner that what floats around Los Angeles everyday!!

1) I wouldn't plan on having that picnic during regen.

2) Have you checked the price of a replacment DPF ? If you buy new/sell often, then it's a Don't Care, but for many of us, these "downstream" issues are a concern.

Rgds, D.

 

[Gale Hawkins]

Without a question diesel engines are awesome tractor engines of any size and about the only thing one sees in most of the world.

With that being said I grew driving tractors in the 50's and 60's and most all were gas. In our case we had the 800 series Fords with gas engines. When we just had one we often ran it 18+ hours a day in the spring. They were very long life engines and we never ran them over 1800 RPM which equaled 540 PTO RPM.

I expect the concerns of tier 4 will blow over. I do not see anyone going back to building gas tractors of any size unless the cost to build diesel engines get much greater than gas. Since I do not tow much I do not ever see myself owning a diesel pickup truck however due to the upfront cost.

 

[Squeak n Itch]

Admittedly this is a vehicle engine, but Ford Motor Company developed a 6 cyl twin turbo engine that has high hp and torque at a low rpm relative to other vehicle engines.

Diesel engines around the world perhaps respond to local refinery capabilities and therefore fuel availability as well as higher energy content per gallon. With considerably lower volatility diesel is generally regarded as "safer".

 

[rjkobbeman]

The tier 4 crap is causing headaches in the automotive world too. New diesel truck owners can tell you all about it.

Whether a better solution is found, nobody knows. For now it is bandaid over patch over jury-rig.

One thing is for sure, the idea of a gas engine replacing a diesel in a tractor is much more doable today than ever before.
Gas engines have come a long way since they were used in tractors. That, and the way most tractors are used (slow with tons of gearing), I can see gas working.

The issue may become more problematic when you get into bigger tractors, however for the small to mid... why not?

Gassers can be made with long strokes for lots of torque. They don't have to be high revving screamers.

 

[Kubota 2350]

A tractor without a diesel is just not right.:laughing::laughing: