Any news on gas engine CUTS?

[buickanddeere]

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.

Gasser in the past have had their efficiency limited due to detonation that occurs with compression and thus expansion ratio's above 8 to 1 ratio. Now DI gassers have a 12 to 1 expansion ration and no concerns about detonation. Diesels go higher on the compression ratio in order to cold weather start. Efficiency improvements start dropping rapidly per unit of compression after the 11-12 to 1 ratio range. The extra power required to make the extra pressure on the compression stroke and the extra compression heat made and thermal efficiency lost limits the gains on the expansion stroke. Take a look at the difference in power and efficiency of the Chev 5.3 port injected vs the Chev 5.3 direct injected.
Lets not forget an engine makes power on the pressure difference between the compression pressure and the combustion pressure.
Lets compare the DI turbo Chevy Cruze eco gasser for $21,500 and obtains 26 city, 31 combined and 39 highway. $1000 a year in fuel according to the EPA test. vs the Cruze diesel turbo for $25,295 , 27 city, 33 combined and 46 highway, $1300 a year in fuel according to the EPA. Tell us here ,where the diesel advantage is. Lets also consider that gasoline with only 88% as much energy per gallon as diesel being very close to the diesel mileage. Certainly cheaper to purchase, cheaper to drive and cheaper to service the DI gasser.

 

[GManBart]

Gasser in the past have had their efficiency limited due to detonation that occurs with compression and thus expansion ratio's above 8 to 1 ratio. Now DI gassers have a 12 to 1 expansion ration and no concerns about detonation. Diesels go higher on the compression ratio in order to cold weather start. Efficiency improvements start dropping rapidly per unit of compression after the 11-12 to 1 ratio range. The extra power required to make the extra pressure on the compression stroke and the extra compression heat made and thermal efficiency lost limits the gains on the expansion stroke. Take a look at the difference in power and efficiency of the Chev 5.3 port injected vs the Chev 5.3 direct injected.
Lets not forget an engine makes power on the pressure difference between the compression pressure and the combustion pressure.
Lets compare the DI turbo Chevy Cruze eco gasser for $21,500 and obtains 26 city, 31 combined and 39 highway. $1000 a year in fuel according to the EPA test. vs the Cruze diesel turbo for $25,295 , 27 city, 33 combined and 46 highway, $1300 a year in fuel according to the EPA. Tell us here ,where the diesel advantage is. Lets also consider that gasoline with only 88% as much energy per gallon as diesel being very close to the diesel mileage. Certainly cheaper to purchase, cheaper to drive and cheaper to service the DI gasser.

The EPA doesn't use ethanol gas in their tests, although they claim to factor that in when they publish their mileage figures....so they're guessing a little bit.

The glaring omission in your comments is that the diesel Cruz has 151hp @4,000rpm compared with 138hp @4,900rpm for the gasser. Even more telling is that the diesel has 264lb/ft of torque at 2,600rpm to the gassers 148lb/ft at 1,850rpm. That means the diesel is going to perform much better, and still get better mileage. This is what we call an apples-to-oranges comparison again.

I'd be glad to pay $300 more per year for a car that performs significantly better when you're talking cars that are on the low end of the power-to-weight ratio.

Further, the price per year fuel figures are based upon theoretical fuel costs, not actual costs. Until the recent huge drop in gasoline prices, diesel wasn't much more expensive than regular gas around here.

 

[buickanddeere]

The EPA doesn't use ethanol gas in their tests, although they claim to factor that in when they publish their mileage figures....so they're guessing a little bit.

The glaring omission in your comments is that the diesel Cruz has 151hp @4,000rpm compared with 138hp @4,900rpm for the gasser. Even more telling is that the diesel has 264lb/ft of torque at 2,600rpm to the gassers 148lb/ft at 1,850rpm. That means the diesel is going to perform much better, and still get better mileage. This is what we call an apples-to-oranges comparison again.

I'd be glad to pay $300 more per year for a car that performs significantly better when you're talking cars that are on the low end of the power-to-weight ratio.

Further, the price per year fuel figures are based upon theoretical fuel costs, not actual costs. Until the recent huge drop in gasoline prices, diesel wasn't much more expensive than regular gas around here.

So what about the power and torque. The average driver doesn't even know. Both vehicles accelerate up to highway speeds without being floored.
$300 a year for fuel. I don't hear you being glad about the extra cost of the diesel option. Nary a peep either about paying the dealership to work on that emission diesel.
The DI gasser has displaced the diesel in the light to medium duty market.
The price of diesel has been more expensive than gasoline for the past eight years in the US. How and when do you expect that to change?

 

[buickanddeere]

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.

What is the price difference between gasoline and Diesel per gallon?
Why won't you acknowledge that diesel efficiency drops when the engine is not constantly operated at full rpms and full load? I gave you the results of the Nebraska test of the partly to fully loaded IH 105C . We are awaiting you comments regarding diesel efficiency in the light duty puttering around CUT application. Nor have you said a peep about initial purchase and service costs on that Tier IV diesel.

 

[GManBart]

So what about the power and torque. The average driver doesn't even know. Both vehicles accelerate up to highway speeds without being floored.
$300 a year for fuel. I don't hear you being glad about the extra cost of the diesel option. Nary a peep either about paying the dealership to work on that emission diesel.
The DI gasser has displaced the diesel in the light to medium duty market.
The price of diesel has been more expensive than gasoline for the past eight years in the US. How and when do you expect that to change?

So the folks that don't care about significantly better performance don't buy the diesel....simple. Those that want the extra performance can have it...nobody is forcing them.

If they made that Cruz gasser so that it put out the same power and torque as the diesel (if possible) it would use significantly more fuel than it does now, which would make the fuel economy difference even larger than it is.

You're talking about an engine powering a tractor, but you use a Chevy Cruz engine to make your argument...that's pretty funny. Looking at the specs between those two engines, it's obvious which one would do a far better job of powering a tractor, all while getting better fuel economy....and it's not the gasser.

Diesel can cost more than gas because there's more energy per gallon in it, and the engines get more out of each gallon of diesel...again, these facts aren't news.

 

[GManBart]

What is the price difference between gasoline and Diesel per gallon?
Why won't you acknowledge that diesel efficiency drops when the engine is not constantly operated at full rpms and full load? I gave you the results of the Nebraska test of the partly to fully loaded IH 105C . We are awaiting you comments regarding diesel efficiency in the light duty puttering around CUT application. Nor have you said a peep about initial purchase and service costs on that Tier IV diesel.

The price difference varies over time, and by location. In much of the world diesel is less expensive than gasoline, so it only takes a slight increase in fuel economy to pay for any increased purchase price....which is why we see diesels as the norm for most of the world. Historically, diesel has been less expensive than gasoline, and part of the reason for the change is the expense required for U.S. fuel producers to change to ultra-low sulfur fuel....that cost goes to the consumer. Also, diesel fuel has lower taxes than gasoline. All of those things are subject to change, but what isn't subject to change is that diesels are more efficient and diesel fuel has more energy per gallon in it.

The cost of diesel emission control equipment will drop as the technology matures, and more units are sold...this is pretty simple economics.

If someone thinks they can make a gasser tractor that will work out well they should give it a whirl. If you think the folks on this forum know more than the folks making tractors for a living, that's a pretty arrogant thought. If they thought they could sell more tractors, or make a higher profit margin by offering gassers, they would.

There has to be a reason why they haven't....hint, it's because they probably won't work as well, won't be as efficient, won't last as long, and they won't sell enough of them to ever recoup their costs for testing, developing, designing, tooling, etc.

 

[PoorPlowboy]

Torque demands ? What ? How did gasoline farm tractors in the past and light equipment today operate ? They made torque . Actuly torque alone Accomplishes nothing.
Take a look at the Nebraska test for tractors with gasoline and Diesel engines in the same model. The gasser made as much or more torque and HP per cubic inch as the diesel.
Gas engines are not concerned with glow plugs, turbos, 30,000 psi injection systems, particulate filters, urea injection, cold weather gelling of fuel and cold weather starting .

Gassers are plagued by no legal means to transport bulk fuel for them. In my area, it is against the law to transport more than 15 gallons of gasoline in marked and approved containers. That won't get me through a full day of mowing with my '46 M. Its also plagued by points and condensors, rust in the fuel tank (all my diesels have poly cells) and fouled spark plugs if not kept in tune. There's drawbacks to them all, no matter what fuels them.

 

[PoorPlowboy]

It is illegal to carry gasoline in a bed mounted fuel transfer tank. I dont enjoy climbing on top of a 6ft tall hood to fill a tank 5 gallons at a time. My gassers are relegated to hobby tractors.

 

[PoorPlowboy]

Gasoline is out. Natural gas is in. Cummins is converting just about every engine they make to a gas head offering.

You are being redirected...

A 3.3L 4CYL DI turbo LNG would make a fine little tractor motor if the fuel infrastructure was there. It would probably make 250+ horsepower.

 

[john_bud]

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.

Good point. But diesel engines w the epa stuff is a thousands of dollars premium. Then the fuel costs 25-30% more per gal.

I have 3 diesel tractors, 1 gas tractor and a diesel truck. In the winter, the modern diesels start good enough w glow plugs and grid heaters. But the old gaser fires up just by choking and it's 6v! The truck tows heavy and diesels rock at that ... but... given the total cost picture, my next truck dang sure won't be diesel. Higher initial cost, higher maint costs, 25% better mpg - but 30% higher fuel cost. There is no payback that I can find.

I'm sure if they engineered a small stout gas engine for a tractor it would be popular in many diesel applications.