fuel efficiency gasoline engines?

wilson ind · Apr 5, 2018

Discussing with friend regarding John Deere 3020 gasoline as to other tractors of same horsepower. Valve timing, valve grind, and air circulation are possibilities. What factors may or may not be valid. Opinions please.

Ken Macfarlane · Apr 5, 2018

Efficiency of gas engines is mostly related to compression ratio and mean effective pressure. Timing effects MEP.

Lots of people get factors that build hp with those that make hp.

Janicholson · Apr 5, 2018

Ken Is correct. Cylinder, chamber, piston temperature (the higher the better, as it allows less perimeter quench of combustion flame) adds to efficiency. Small surface area at MEP reduces unburned fuel. Pumping efficiency Scavenging and intake ram effect are contributors. Internal friction reduction adds efficiency (smaller journals thinner oil, roller cams, oil pan windage).
Nothing really is a high % change but every detail is critical. farm tractors are not in this mix of tweaking for every erg, and have never been designed to be that way. Jim

JDEM · Apr 5, 2018

Define "efficiency." In the context of a tractor intended for work - it is about the cheapest cost per horsepower-hours. Increasing compression to get slightly more work per gallon is not a gain if more expensive fuel must be used. If durability and longevity is lowered, then also no net gain.

I suspect there is little you can do to improve what Deere already spent a lot of time on - unless you plan to redesign the engine.

Oliver might still hold the record for efficiency in a gas tractor since they managed to use 8.5 - 1 compression and run regular gas. Quite a trick with no advanced electronics. Oliver 1800 beat many diesels with work done per gallon of fuel.

Ken Macfarlane · Apr 5, 2018

Meant to say, lots of people confuse hp measures with efficiency measures.

docmirror · Apr 5, 2018

IC engine efficiency is measured in Brake Specific Fuel Consumption. A lot of words, and a lot of graphs, and a lot of work has been done on this over the years. tractor, car, truck, train, pump, doesn't matter what it's driving, a fuel efficient engine has a low BSFC number.

There are so many variables it's hard to even put a dent in it. The thermodynamic limits of a gasoline engine are about 14:1 compression with good quality hi octane fuel.

Best modern IC engines get about .36 BSFC in the auto world.

David G · Apr 5, 2018

All of them, plus many many more.

rlp in Co. · Apr 5, 2018

The two cylinder john Deere's were efficient because of their low rpm and low friction with only two cylinders. The low compression to run on distillate hurt when running on gasoline. The two cylinder diesel held record efficiency of pounds of fuel per horsepower hour. It may still hard to beat with modern diesels. My old ford 3 cylinder backhoe will use less fuel than my bosses 4 cylinder John Deere doing the same amount of work. The newer diesel trucks are running at a lower rpm than the older trucks and getting better fuel mileage. Another benifit is the engine lasts longer. Sorry I got carried away and started talking about diesels.

JDEM · Apr 6, 2018

If your two-cylinder hypothesis held true - a four-cylinder Deere diesel would not have beat the two-cylinder Deere diesel like the 1650 did in 1983.

Same goes with a four-cylinder 2020 beating the two-cylinder 520 both in max power and efficiency at same power levels.

520 with a 190 c.i. two-cylinder engine made a max 37.5 HP at 11.46 HHG efficiency.

2020 with a 180 c.i. four-cylinder engine made a max 53.9 HP at 11.17 HHG efficiency.
When run at at a lower 48 HP, the 2020 scored 11.89 HHG.

rlp in Co. · Apr 6, 2018

Well, you're right and I'm wrong! Ha

fuel efficiency gasoline engines?

wilson ind

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Ken Macfarlane

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Janicholson

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JDEM

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Ken Macfarlane

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docmirror

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David G

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rlp in Co.

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JDEM

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rlp in Co.

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