Any news on gas engine CUTS?

[Loadstar]

The real interesting thing is in comparing the specifications of that engine as an industrial engine vs. its specifications as an automotive engine. That engine you listed is the 2.3 L version of the Mazda L series four-cylinder aluminum-blocked, port EFI, DOHC engines. My mother's first-gen Fusion has this exact engine. The industrial specs have it governed at 3200 rpm, making about 80 hp and 130 ft-lb torque. The engine is rated at 160 hp and 156 ft-lb in the Fusion, and the redline is around 7000 rpm.

They are similar but not the same.

 

[SPYDERLK]

Only on paper...in theory... as I'm sure you know....

A 25hp diesel will have more real-life, usable power than a 25hp gasser due to a diesel making its power at a lower rpm and making much more torque. Different engines will make their power in different rpm ranges depending on the application it is built for.

So in pracrice, 25hp is not 25hp is 25hp.

I think you are really trying to say that the flatness of the torque curve is really what we are looking for. A peaky engine with no torque until high speeds is not very tractable; one with a lot of torque from down low in the RPM range is very tractable. The torque curve is affected by a bunch of factors such as compression ratio, cam profile and timing, injection timing, bore vs. stroke ratio, intended operating speed range, the particular setup of your forced induction (if present), etc. etc. You can certainly make a gasoline engine with an extremely flat torque curve which would be better than a similar-sized diesel's. Just look at a modern undersquare multiple-small-diameter-turbo DI gasoline engine. Torque curves are essentially a straight line on them from not much above idle on through redline due to how the turbos are set up.

We were talking HP at the time. ... But yes, a flat torque curve ensures tractability, and since they are inseparable, also ensures a lot of area under the HP curve.
larry

 

[Loadstar]

Right just as any industrial engine they are governed to only be able to rev within a set parameter. Now take the governor off anything and see what happens. I am not saying you lied about your buddies car but I am sure somehow someone does not have all the facts!

Now go take any gas powered car and run it in first gear without sending the RPM into redline and you will find that if you govern the RPM so that it does not over rev (just as your tractor engine is governed) that it will not blow up

My F150 only has a 300 six and pulling the wagon over the mountain is a stressful job for it as its at more than twice what it should be pulling and it gets held flat to the floor from the bottom of the mountain to the top. About 6 miles flat to the boards in first gear 2 sometimes 3 times a week since 1989 and it has yet to blow up as the work load wont let it get that much RPM. But I could do the same thing with no load if I was to install a governor and have no worries of ever blowing it up. So what we are saying is your argument is mute because you are picking on something buy using examples that simply don't fit what would be the intended use or any realistic design that would be used if a gas engine were to be installed in a scut or a cut.

Now a machine that carries more base weight from the start, lifts and carries more weight overall, at a longer interval being pegged right to the rev limiter/governor when compared to my tractor which carries less weight, lifts less weight and is never run at its max RPM but run close to PTO speed but almost never above, you consider to be light duty? If anything My DK is light duty compared to the lifts I have seen, used and abused.

My next question is how do you know what rated power is for every fork lift built like most of us here know what our tractors rated power is? Fact is the fork lift and industrial engines are built to attain max power (torque) within the rpm they are governed to so that they are useful machines just like your tractor engine is built to attain its most useful power within its governed rpm range.

I don't know about this... I was on a jobsite today and gas engines were blowing up left and right in all types of equipment. As soon as they revved up to work kaboom.


Lol

 

[GManBart]

There you go , what I been trying to tell you all along. Light , medium or HD applications, they differ in power plant requirements . A modern spark ignition engine works better than a diesel in light/medium duty applications such as a fork lift.

We're talking about tractors, not fork lifts....sheesh.

 

[paulfun9]

I don't know about this... I was on a jobsite today and gas engines were blowing up left and right in all types of equipment. As soon as they revved up to work kaboom.


Lol

What Do you think diesel engines don't blow up? I have seen many go south without warning. Broken rods, cracked pistons, broken cranks warped heads burnt bearings ect. I wonder why I can always find a remand diesel engine without much trouble?

 

[GManBart]

Right just as any industrial engine they are governed to only be able to rev within a set parameter. Now take the governor off anything and see what happens. I am not saying you lied about your buddies car but I am sure somehow someone does not have all the facts!

Now go take any gas powered car and run it in first gear without sending the RPM into redline and you will find that if you govern the RPM so that it does not over rev (just as your tractor engine is governed) that it will not blow up

You're right, you don't have all the facts. You also seem to lack some basic knowledge of Corvettes. When was the last time you saw a Corvette that didn't have a rev limiter built in to keep it from going past redline? I'm not an authority, but I believe 1984 was the first year they had them. Awe heck, they've only been around for three decades...anybody could overlook that. About the only way to seriously over rev a stock modern Corvette is during a downshift, but that wasn't how this happened...steady state, going down the road in first gear. The car was dead stock since it was only a few months old and he knew better than to modify anything since he had a warranty problem developing. He ran it right under the rev limiter until it turned itself into shrapnel....contrary to your "theory" which I'm guessing you've never actually tested.

Simple fact, light-duty engines like what we see in cars and light trucks can be damaged while operating within their RPM/load limits. Heavy-duty cycle engines normally can't hurt themselves even with an idiot operator....wide open throttle, in any gear, and they won't be damaged. That's the difference.

So what we are saying is your argument is mute because you are picking on something buy using examples that simply don't fit what would be the intended use or any realistic design that would be used if a gas engine were to be installed in a scut or a cut.

An argument that can't speak? I'm not "picking" on anything, I'm pointing out ridiculous comparisons that people are making here...not one includes an engine operating at rated power for hours on end.

Now a machine that carries more base weight from the start, lifts and carries more weight overall, at a longer interval being pegged right to the rev limiter/governor when compared to my tractor which carries less weight, lifts less weight and is never run at its max RPM but run close to PTO speed but almost never above, you consider to be light duty? If anything My DK is light duty compared to the lifts I have seen, used and abused.

My next question is how do you know what rated power is for every fork lift built like most of us here know what our tractors rated power is? Fact is the fork lift and industrial engines are built to attain max power (torque) within the rpm they are governed to so that they are useful machines just like your tractor engine is built to attain its most useful power within its governed rpm range.

I don't know what sort of crazy businesses you've been involved in, but I've never seen fork lifts operated with their engines making rated power, or close to it for hours on end....throttle set in one position and left there. Carrying weight, lifting weight etc has nothing to do with the duty cycle of the engine....stop trying to even include that. The only thing that matters is how much power the engine is making, relative to it's maximum power, and how long it makes that amount of power. Power relative to weight will influence speed (and transmission choices) but won't change the duty cycle of the engine. This really isn't overly complicated.

Trying to suggest that a fork truck engine is built for as heavy a duty cycle as a tractor engine is pretty comical....seriously, it's really funny. :laughing:

 

[GManBart]

No, it doesn't make the same peak power, as the gas engine, when compared $ for $ or lb for lb. That's a common diesel reasoning fallacy. Your comparing a much heavier, much more expensive diesel to a lighter, cheaper gas engine. Not fair. If you compare engines of the same price or weight, you would find they are quite comparable. The main drawback to a gas engine is it throws more wasted heat energy than the diesel, and the fuel is flammable/unstable.
You can get a V8 gas engine of the same price or weight as a 3, or 4 cylinder diesel. The equal $, or weight V8 can be geared to run 'just above idle' and would make the same power as the smaller diesel. At that low RPM the gas engine could last 'forever'. The big drawback...again..is the big gas engine would use more fuel.

You're making my point. The engine in a fork truck is lighter, and cheaper because it can be lighter and cheaper and still not fail. That wouldn't be the case if you put that engine in a tractor. It would have to be heavier, and more expensive to survive. I was pointing out that a modern tractor engine of the same horsepower is (in this case) 50% bigger...there's a reason for that. The manufacturers aren't arbitrarily making the engine any larger or more expensive than necessary.

Short version....tractor duty cycles are harder than fork truck duty cycles and that changes engine requirements. For whatever reason, folks are trying to use fork truck engines as some sort of comparison they think is valid, but it's clearly apples-to-oranges.

 

[paulfun9]

Simple fact, light-duty engines like what we see in cars and light trucks can be damaged while operating within their RPM/load limits. Heavy-duty cycle engines normally can't hurt themselves even with an idiot operator....wide open throttle, in any gear, and they won't be damaged. That's the difference.



QUOTE]

Yep wide open throttle with an engine that is restricted by a mechanical device that is designed to keep the RPM from going into the danger zone where it will come apart. But yet I have seen many fail over the years just as I have seen gas engines fail!

By the way I am not sure when they started installing rev limiters on vettes but my 86 didn't have one and if it did it was way up past the indicated red line as I never found it and I am not the type that babies anything.
As for running sustained at a higher RPM for extended periods I have done that also! I honestly drove what would be about a 2 hour drive at the speed limit with nothing left but first gear in my Firebird after blowing the tranny at a back street race in the city! New tranny the next weekend and the engine never skipped a beat and Its still going strong today. If you don't believe that you can come over and I'll take you for a ride in a fire breathing Big Block Firebird as I still have the car. We can even do some extended first gear runs with the tack just below red line but again I am not silly enough to ride around bouncing off the rev limiter as we all know how badly that ends when someone holds against the momentary cut off of a factory installed set up. Power on/ power off for extended period of time is what killed your buddies car not holding it wide open. Fact is if I put a light load on your tractor and ran it wide open and cut the fuel on and off just as rapidly as the electronics on the car can it would also blow.

 

[Loadstar]

You're right, you don't have all the facts. You also seem to lack some basic knowledge of Corvettes. When was the last time you saw a Corvette that didn't have a rev limiter built in to keep it from going past redline? I'm not an authority, but I believe 1984 was the first year they had them. Awe heck, they've only been around for three decades...anybody could overlook that. About the only way to seriously over rev a stock modern Corvette is during a downshift, but that wasn't how this happened...steady state, going down the road in first gear. The car was dead stock since it was only a few months old and he knew better than to modify anything since he had a warranty problem developing. He ran it right under the rev limiter until it turned itself into shrapnel....contrary to your "theory" which I'm guessing you've never actually tested.

Simple fact, light-duty engines like what we see in cars and light trucks can be damaged while operating within their RPM/load limits. Heavy-duty cycle engines normally can't hurt themselves even with an idiot operator....wide open throttle, in any gear, and they won't be damaged. That's the difference.

An argument that can't speak? I'm not "picking" on anything, I'm pointing out ridiculous comparisons that people are making here...not one includes an engine operating at rated power for hours on end.

I don't know what sort of crazy businesses you've been involved in, but I've never seen fork lifts operated with their engines making rated power, or close to it for hours on end....throttle set in one position and left there. Carrying weight, lifting weight etc has nothing to do with the duty cycle of the engine....stop trying to even include that. The only thing that matters is how much power the engine is making, relative to it's maximum power, and how long it makes that amount of power. Power relative to weight will influence speed (and transmission choices) but won't change the duty cycle of the engine. This really isn't overly complicated.

Trying to suggest that a fork truck engine is built for as heavy a duty cycle as a tractor engine is pretty comical....seriously, it's really funny. :laughing:

Dang, I wonder why they put such oversized engines in them? Really they could just put a 5hp Briggs and Stratton in and be done with it. I mean since it takes no effort to do all that.

 

[SPYDERLK]

Lots of good thinking if you only can get past the sloppy comparisons so you can make sense of it. ... A revved engine is only at full throttle if it is carrying a full rated load. A non loaded engine running at it rated rpm is in a High Idle mode, putting out only enuf power to spin. The Corvette blew up at very low load - similar to hi idle. Something was wrong with it.

Forklifts never go for extended periods under hi load condition.

 

[GManBart]

Dang, I wonder why they put such oversized engines in them? Really they could just put a 5hp Briggs and Stratton in and be done with it. I mean since it takes no effort to do all that.

Nobody said anything like "it takes no effort to do all that." It's just a simple fact that fork truck engines don't get set at rated power and left there for hours on end, much less have the ability to take shock through the driveline the way a tractor engine does like when using a tiller or rotary mower.

I simply can't understand why people are so confused by this. Tractor engines are made the way they are, and cost what they do, because that's what's required to have an engine that will provide the power, reliability, and durability we expect from them. Tractors aren't cars or fork trucks or gensets, or any of the other things people want to use as comparisons, so the demands placed upon them are different.

 

[Loadstar]

Nobody said anything like "it takes no effort to do all that." It's just a simple fact that fork truck engines don't get set at rated power and left there for hours on end, much less have the ability to take shock through the driveline the way a tractor engine does like when using a tiller or rotary mower.

I simply can't understand why people are so confused by this. Tractor engines are made the way they are, and cost what they do, because that's what's required to have an engine that will provide the power, reliability, and durability we expect from them. Tractors aren't cars or fork trucks or gensets, or any of the other things people want to use as comparisons, so the demands placed upon them are different.

-Starting and stoping loaded is harder on an engine than a fixed continuos load in the power band.
(we probably agree on that)

-engines of any petroleum based fuel can run in their optimum power band they were designed for, for a long time.
(we probably agree on that)

-gas engines of years ago withstood the test of time. They were built much stronger then. Some probably stronger than a present diesel of similar hp. So not a great comparison for modern gas or diesel.
(we probably agree on that)

With that said I don't think a gas engine would be a total bust in cuts maybe not the best move but many have no interest in modern emissions diesels they are forced due to lack of options. A gas engine with today's ignition and fuel injection in a tractor would work. Yes some components would have to be beefed up. I don't foresee manufacturers spending money on R+D and production changes for this though. I have gas and diesel trucks and tractors. If I could switch my older gas ford to a multiport injected distributorless engine tomorrow I would because it's industry proven tough. Diesel tractors do their job and do it well I have no argument there.

 

[buickanddeere]

Hint: My post said "SCUT/CUT". I know full well where they are and where they aren't ... that's kind of the point of THE LAST 44 PAGES!

We are saying the spark ignition engine will make inroads into the CUT and other light and medium duty equipment . Where Tier V emissions and where diesel costs more than gasoline or LP.
Kubota for example has a whole line of spark ignition engines. High compression DI engines in light highway applications are crowding the Tier IV diesel out. With mileage per btu near to or equal to diesel. Small Injected gas engines in lawn equipment and off-road vehicles provide diesel mileage where a diesel is not practical. The engines are out there now. Tier V emissions and when diesel prices rise again will push the spark ignition farther into the current light diesel market.

 

[buickanddeere]

We're talking about tractors, not fork lifts....sheesh.

Uncle Putz out puttering around with his CUT, SCUT, off road ATV and lawn equipment . Has a similar duty cycle to a forklift.
A diesel is built for and works best at continuous full rated rpm and full load. Moving into the post 2007 emissions era with particulate filters. Particulate diesels do not fare as well idling, start-stop duty and putting around at part load at low rpm .anybody remember the tendency idling diesels to wet stack?

 

[Hinomotoman]

No one has mentioned compression ratios. If you tried to put 23/1 compression on a gasoline engine, it would be disasterous.

Eugene

 

[buickanddeere]

You're making my point. The engine in a fork truck is lighter, and cheaper because it can be lighter and cheaper and still not fail. That wouldn't be the case if you put that engine in a tractor. It would have to be heavier, and more expensive to survive. I was pointing out that a modern tractor engine of the same horsepower is (in this case) 50% bigger...there's a reason for that. The manufacturers aren't arbitrarily making the engine any larger or more expensive than necessary.

Short version....tractor duty cycles are harder than fork truck duty cycles and that changes engine requirements. For whatever reason, folks are trying to use fork truck engines as some sort of comparison they think is valid, but it's clearly apples-to-oranges.

Again a "tractor" is too broad a brush. Somebody out ploughing 1000acres fulling an average of 180HP from 200HP engine from sunrise to sun set daily. That is a HD service diesel application .
Mr Retired out on his rural estate putting around on his CUT or SCUT "tractor "is not operating at full rated rpms from sunrise to sun set at full power for 1000hrs per season.
Mr Retired light and medium duty service is hauling a bucket of dirt to a flower bed, pulling a lawn sprayer , lawn roller , going to get the mail, carrying a bail of hay to the horse, cleaning stables . Cold starts to move snow is better with a spark ignition too.
Mr Retired will be hard pressed to put 100hrs a year on the CUT or SCUT . How much fuel savings is there going to be ? Zero.

 

[buickanddeere]

No one has mentioned compression ratios. If you tried to put 23/1 compression on a gasoline engine, it would be disasterous.

Eugene

Please tell use how or why that is a valid line of reasoning and pertinent to the conversation . Btw the DI gas in Mrs B&D's ride runs just fine at 11.6 to 1 on 87 octane.
The "high" compression ratio is all about increasing thermal efficiency on the power stroke . When throttled the compression ratio maybe as low as 4 to 1 when cruising. This is where a throttled spark ignition beats a diesel's thermal efficiency at part load.
Have you ever seen throttle blades outside the first stator blades on a stationary gas turbine engine ? They are there to improve part load thermal efficiency.
Why do you think higher compression is better? Are you aware of how the basic Otto cycle Brayton design operates . It's all about effective pressure under the curve on the power stroke vs the average pressure in the compression stroke. The engine works by heating and thus increasing combustion chamber pressure after the compression stroke. The delta T and thus the delta P is lower when the combustion chamber is hotter rather than cooler. A high compression ratio has already used power stroke energy to dump more heat into the combustion chamber with high compression vs low compression .why do you think intercoolers are used on reciprocating diesel and on gas turbines between the compressor stage and combustion chamber ? To improve thermal efficiency , reduce max combustion temps and increase max possible full rated power.

 

[hutchman]

This is where a throttled spark ignition beats a diesel's thermal efficiency at part load.

I hate to bring up auto comparisons again but I can't let a comment like that stand ... there is NO straight gasser (and I'm even including those stupid little SMART cars) that can best the highway MPG of my 2002 VW Jetta TDI. Heck, I don't think there is one that can beat my 2006 TDI either so I'm tired of you spouting off how much more efficient the gasser is when it simply isn't so. If there was something out there (that wasn't as big as a pregnant roller skate) in a gasoline engine that efficient as you say I'd be driving it. I used to drive 1 1/2 hours one way to work ... I know what I'm talking about. It pains me I'm not driving an American car but cents per mile is what is important to me and I'm rolling in the vehicle that has that capability ... 13yrs old now and will still break 50MPG on highway ... speeding and AC blasting.

 

[hutchman]

I hate to bring up auto comparisons again but I can't let a comment like that stand ... there is NO straight gasser (and I'm even including those stupid little SMART cars) that can best the highway MPG of my 2002 VW Jetta TDI. Heck, I don't think there is one that can beat my 2006 TDI either so I'm tired of you spouting off how much more efficient the gasser is when it simply isn't so. If there was something out there (that wasn't as big as a pregnant roller skate) in a gasoline engine that efficient as you say I'd be driving it. I used to drive 1 1/2 hours one way to work ... I know what I'm talking about. It pains me I'm not driving an American car but cents per mile is what is important to me and I'm rolling in the vehicle that has that capability ... 13yrs old now and will still break 50MPG on highway ... speeding and AC blasting.

.... and before you try to call me a liar again like the last time we had this conversation maybe you need to spend some time reading here:

60 MPG / 900 Mile Club / 1000 Mile Club - TDIClub Forums

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