Any news on gas engine CUTS?

[buickanddeere]

the Kubota is a BX2200D

The Kubota was probably 6-7 thousand bucks new as a premium quality tractor and deck. The D130 is a bottom end entry level machine built for the customer who wants low price above all else. Right down to the flimsy K40 transmission and $1900 cost. It's safe to say that compromises in design to make do with lighter, weaker, lower cost components have reduced operating efficiency. Lets try the Kubota against a comparable X700 series JD lawn tractor.

 

[buickanddeere]

I've found what you say to be true too... The diesels just plain keep the blade speed higher in deeper grass, so they cut better. The torque of the diesels really helps with this...

SR

The 22 gross HP Kubota had 16.7 pto HP net. What net HP did the 22 gross HP D130 have at the mower pulley net after the drag of that cheapo Tuff Torq K40
transaxle and all the other losses?

 

[davesl708]

The 22 gross HP Kubota had 16.7 pto HP net. What net HP did the 22 gross HP D130 have at the mower pulley net after the drag of that cheapo Tuff Torq K40
transaxle and all the other losses?

Keep in mind the Kubota is 16.7 @ the pto then has to drive another gearbox and three blades. It is cutting 18"more width of grass and weighs 1300lbs. as well.
John Deere does not provide hp rating to the 42" deck. Weighs 470lbs. The Kubota is working a lot harder to cut the grass.

The discussion has been 22hp gas equals 22hp diesel.

 

[GManBart]

Tractors are meant to be run for hours and hours and hours, over many years. Modern DI gas engines max out around 35% efficiency. Modern common rail diesel engines can take that figure up to 50%. 15% better efficiency will pay for itself over time when you're talking extended run time over many years.

That's really what the argument boils down to.

 

[tduby]

Tractors are meant to be run for hours and hours and hours, over many years. Modern DI gas engines max out around 35% efficiency. Modern common rail diesel engines can take that figure up to 50%. 15% better efficiency will pay for itself over time when you're talking extended run time over many years.

That's really what the argument boils down to.

that and the added expenses of the new tier IV emissions related components. I am not looking forward to the next few years when these boards are filled with all the griping of it cost me $$$$ to replace the particulate filter or the Hay crop lost because of EGR cooler failure that took down a tractor for 3 days. Plus for most of the year it seems like diesel is 70-90 cents a gallon more. As a logging truck owner operator I will keep running my 2001 Cummins powered Kenworth till the day I retire or the technology finally works right in 10 -15 years.

 

[buickanddeere]

Tractors are meant to be run for hours and hours and hours, over many years. Modern DI gas engines max out around 35% efficiency. Modern common rail diesel engines can take that figure up to 50%. 15% better efficiency will pay for itself over time when you're talking extended run time over many years.

That's really what the argument boils down to.

Again some people are not getting the concept of light duty and HD service. Uncle Bubba putting around in the yard with his 35HP CUT is light duty service. Bubba Jr out V-Ripping 2000 acres is using his 300HP tractor in HD service.

Where pray tell are you getting those efficiency numbers from? Nebraska Tractor tests with the largest tractors which are the most efficient operating then at constant full load . It's uncommon to find tractors making better than 18HP per gallon per hour and 19HP per gallon is rare and particularly outstanding with 37.3 % efficiency turning diesel fuel into shaft HP.
Gasoline at the same level of efficiency which is pretty close for a modern DI gasser would be 16.7 HP per hour per gallon.
As gasoline while cleaner burning as it has less carbon which makes fewer btu than hydrogen vs diesel. Gasoline contains 88% of the energy of diesel per gallon. Notable difference in price per gallon between diesel and gasoline however.
As for part throttle efficiency of a diesel. There is a long line of people here who think that a diesel that makes 19HP per gallon per hour at pto speed and 100% of rated load. Also makes 19HP per gallon per hour at any task from driving across the yard, loader work , haling wagons etc. Ain't so.
Here are the results of the recent tests for the CIH Farmall 105C which tops out at 16.96 HP per gallon per hour or 33.3% . Efficiency drops as load is reduced. Below 1/2 load efficiency rapidly falls off to 12.13HP per gallon per hour or 23.8%. At puttering around loads making 20.8HP the HP per gallon per hour drops to 8.79 or 17.3%.
At gasser can cost less per hour than an exceptional diesel which is working, putting around at part load. No Tier IV emi$$ion$ equipment to purcha$e or $ervice. Last time I looked, since 2007 gasoline has been consistently cheaper than diesel in the US.
The only way to obtain near 50% diesel efficiency is with a Brayton Cycle reciprocating or gas turbine combined with a Rankin Cycle secondary which reclaims some of the Brayton's waste heat.

 

[buickanddeere]

Keep in mind the Kubota is 16.7 @ the pto then has to drive another gearbox and three blades. It is cutting 18"more width of grass and weighs 1300lbs. as well.
John Deere does not provide hp rating to the 42" deck. Weighs 470lbs. The Kubota is working a lot harder to cut the grass.

The discussion has been 22hp gas equals 22hp diesel.

It would be interesting to know how much power the transmission and the mower deck uses on each machine. I may bleed JD green but I would not touch any of the entry level, low cost as a priority lawn tractor in the 100 series and even the X300 & X304.

 

[GManBart]

Again some people are not getting the concept of light duty and HD service. Uncle Bubba putting around in the yard with his 35HP CUT is light duty service. Bubba Jr out V-Ripping 2000 acres is using his 300HP tractor in HD service.

Where pray tell are you getting those efficiency numbers from? Nebraska Tractor tests with the largest tractors which are the most efficient operating then at constant full load . It's uncommon to find tractors making better than 18HP per gallon per hour and 19HP per gallon is rare and particularly outstanding with 37.3 % efficiency turning diesel fuel into shaft HP.
Gasoline at the same level of efficiency which is pretty close for a modern DI gasser would be 16.7 HP per hour per gallon.
As gasoline while cleaner burning as it has less carbon which makes fewer btu than hydrogen vs diesel. Gasoline contains 88% of the energy of diesel per gallon. Notable difference in price per gallon between diesel and gasoline however.
As for part throttle efficiency of a diesel. There is a long line of people here who think that a diesel that makes 19HP per gallon per hour at pto speed and 100% of rated load. Also makes 19HP per gallon per hour at any task from driving across the yard, loader work , haling wagons etc. Ain't so.
Here are the results of the recent tests for the CIH Farmall 105C which tops out at 16.96 HP per gallon per hour or 33.3% . Efficiency drops as load is reduced. Below 1/2 load efficiency rapidly falls off to 12.13HP per gallon per hour or 23.8%. At puttering around loads making 20.8HP the HP per gallon per hour drops to 8.79 or 17.3%.
At gasser can cost less per hour than an exceptional diesel which is working, putting around at part load. No Tier IV emi$$ion$ equipment to purcha$e or $ervice. Last time I looked, since 2007 gasoline has been consistently cheaper than diesel in the US.
The only way to obtain near 50% diesel efficiency is with a Brayton Cycle reciprocating or gas turbine combined with a Rankin Cycle secondary which reclaims some of the Brayton's waste heat.

I was talking engine efficiency, not machine efficiency, which is what the Nebraska tests publish. The best gas engines top out at around 35% efficiency. The best diesel engines top out around 50% efficiency. Those are apples-to-apples numbers. When you add in the variable of the rest of the machine it becomes apples-to-oranges, because not every manufacturer's systems are going to be the same, and some will be more efficient than others....skewing the figures you see at the PTO.

 

[buickanddeere]

I was talking engine efficiency, not machine efficiency, which is what the Nebraska tests publish. The best gas engines top out at around 35% efficiency. The best diesel engines top out around 50% efficiency. Those are apples-to-apples numbers. When you add in the variable of the rest of the machine it becomes apples-to-oranges, because not every manufacturer's systems are going to be the same, and some will be more efficient than others....skewing the figures you see at the PTO.

I dabble in the industry and I can assure you there is no way a Brayton Cycle is going to approach or slightly exceed the 40% unless it's gross output without operating a cooling fan, water pump, alternator or Tier IV emissions regeneration.
We were talking about Uncle Bubba someday purchasing an under 50HP DI gasser CUT for light duty use instead of a Tier IV diesel . Not Bubba Jr's stripped down stationary irrigation pump motor that operates with less losses.
As for apples and oranges, if you don't measure power at the pto. How are you going to level the playing field ?

 

[GManBart]

I dabble in the industry and I can assure you there is no way a Brayton Cycle is going to approach or slightly exceed the 40% unless it's gross output without operating a cooling fan, water pump, alternator or Tier IV emissions regeneration.
We were talking about Uncle Bubba someday purchasing an under 50HP DI gasser CUT for light duty use instead of a Tier IV diesel . Not Bubba Jr's stripped down stationary irrigation pump motor that operates with less losses.
As for apples and oranges, if you don't measure power at the pto. How are you going to level the playing field ?

Most folks who dabble in the industry know the best diesel engines have roughly 15% better thermal efficiency than the best gasoline engines....this isn't news.

Further, folks defending gas engines always seem to forget that the overwhelming majority of gasoline sold in the U.S. these days has ethanol in it, which lowers it's energy content by around 3% when you're talking 10% ethanol content.

So, we have a diesel system that is 15% more efficient going against a gasoline engine that is hampered by fuel that gives it 3% less efficiency, and that puts the difference in the ballpark of 18% in favor of the diesel.

The only way to do apples-to-apples as you ask would be to put similarly developed diesel and gasoline engines in the same machine and compare PTO outputs. Everything else is really just a guess.