5' or bigger implements by Compact Tractors?

[Pooh_Bear]

Re: 5\' or bigger implements by Compact Tractors?

Open or closed system doesn't matter.
Cooler air is always more dense for the same pressure.
So for the same amount of boost from the turbopump you are better off with cooler air.
This is why there is an intercooler. To cool the charge of air after compressing it.
The only gain from the heat energy is an exaust powered turbopump uses the exaust stream to run the pump rather than robbing power from the engine to drive the pump.
An engine runs better on clean cool air.

Pooh Bear

 

[Spiffy]

Re: 5\' or bigger implements by Compact Tractors?

Cool link hobbyfarm! Now if they only showed the bar-tread version instead of turf... /forums/images/graemlins/grin.gif

Nomad, you are right about the power increase if your pump is capable of supplying more fuel than can be burned. I didn't say efficiency increase only because if you have that much unburned fuel something is designed or set wrong. [admittedly, sometimes a turbo can push a [gas or diesel] engine into a "more perfect" compression ratio, but that's another story].

As far as the air density, by using cooler air you can achieve a higher density without increasing pressure [a cooler can also reduce the added temp from charging]. This is also beneficial in "performance engines" to avoid aditional heat.

I'd agree with Pooh Bear 100% on the exhaust utilization being only relative to driving the turbo [as opposed to super charging consuming engine HP]. However, if the above required conditions [and several earlier posts speaking of component strenth, safety, practicallity, etc] exist blatenly enough to try the experiment, I'd still lean toward super charging so you could "tune" your charger with pully sizes and I'd expect [just educated guess here] a bit flatter torque curve than turbo.

Even if not justified or practical, I'm hoping you try just so we can hear about the good, bad, or ugly! /forums/images/graemlins/grin.gif

 

[chriswheeler]

Re: 5\' or bigger implements by Compact Tractors?

Not a engineer. This is what I do know, running ALL 5' implements at 4800+ feet elevation with a 2600 lb tractor, I can spin the wheels on all if I try. At 4800 feet I'd be lucky to be getting 28 hp out of my 33 hp engine. Traction is a factor with my disk cutting max depth and the HP that is left at that elevation will sometimes spin the wheels. I don't think in most cases the extra hp can be used anywhere except at the pto, pulling, or putting the hp to the ground will be a function of hp and weight. A disk mower? One of my first questions to the board here was if I could get away with running a small haybine behind the 2600 lb tractor with 33 hp. In the end I was left with the impression that due to the weight of the JD 1207 VS the tractor, might work but might not be safe. Found a small turbo on ebay for mine, could turn up the fuel pump, don't think either thing will make my tractor bite the ground better. If you had a stationary engine setup it would be a worth while project, most diesel gensets do.
Chris

 

[nomad]

Re: 5\' or bigger implements by Compact Tractors?

</font><font color="blue" class="small">( Open or closed system doesn't matter.
Cooler air is always more dense for the same pressure.
)</font>

You have a contradiction. Not always so. If the air is in a rigid box (constant volume), pressure will not be same. See:

Pressure (P), Temperate (T), Volume (V), Density (D) and Mass (M).

Assume a M in a constant V (a rigid box). Then, the density will always be same because M (constant) / V (constant) = D (constant). So, pressure (P) of cooler air (lower T) will not be same for a constant volume process. Heat production and heat rejection in internal combustion engines are constant volume process (in diesels, a little different. Heat production, combustion happens at constant pressure, not constant volume) But, in the both of gasoline and diesels, heat rejections are constant volume processes. And, thermal efficiency of engines are related to these heat productions and rejections. And, ideally, efficiency can be expressed as temperature ratios at extremes. Yes, during cooling stage, it will be better to reject the heat out of engine, but piston has to spend some energy to heat the air during the compression stage, doesn't it. So, if we send rejected heat at the exhaust back to the cylinders to help the piston during the compression stage, we will spend less energy to compress (heat) the air during compression and this will increase the efficiency of engine. Anyway. We are going off-topic. Our topic was to increase the efficiency of engine by adding a turbo, hence to increase horsepower of engine to pull a larger implement. And this can be done.

 

[Pooh_Bear]

Re: 5\' or bigger implements by Compact Tractors?

Ok, you got me there. For a closed system it will matter.
Pressure will change with temperature, but density will be the same.
But we're not talking about a closed system.
My understanding of turbocharging is that it needs to send cool pressurized air into the engine. Otherwise the intercooler could be eliminated.

You can increase horsepower by a lot, but you still can't utilize all of it.
Law of diminishing returns still applies.
You can only use enough horsepower to spin the wheels.
And you can only add so much weight till you break something.

Why not just get implements sized to the tractor.

Pooh Bear

 

[nomad]

Re: 5\' or bigger implements by Compact Tractors?

Internal combustion engine complete cycle is considered as a closed system. But, I had said this for another reason. Anyway. At the beginning, I had said my agreement with you about the main reason (more air) of turbocharge and I also agree with cooler air (for intercooler). But, this is to reduce the volume of air (rather than to increase the density) which will enter the cylinder. Yes, more air (by turbocharge) will burn more fuel, hence more powerful. But, its another advantage is to increase the efficiency (by adding more air to increase combustion efficiency by burning the fuel better.) Anyway, we understood each other.

Law of diminishing? You are talking about "only a certain amount of horsepower can be utilized" because of limited load capacity of tractor frame/flywheel/etc ? By adding a turbocharge, we are not increasing HP from 150 hp to 300 hp like it is done in the cars. We are increasing HP only by 20% from 30 hp to 36 hp by making the engine more efficient. Tractor's components (frames, etc) are designed according to this 20-30% tolerances.

Why not sized implements? Compact tractors are relatively much newer items than most of implements which have been manufactured according to 35-50 hp tractors. Instead of sizing implements, why not adding a turbocharger to your compacts?

 

[Spiffy]

Re: 5\' or bigger implements by Compact Tractors?

Cool, you and Pooh Bear are on the same page even more than I thought. Increased density is the same as reduced volume [effectively, not litterally].

I still have a slight problem with the word effeciency [as applied to energy/unit of fuel] gaining the 20% sought, but, I'll assume you have the injection capacity to utilize added oxygen; then it would probably be fair to say you have effeciency as HP/engine constraints or HP/initial investment.

Any, back to the practical side, there is so much more to the handling of a particular tractor than HP: I'd say try your implement of choice without charging the engine. If it works; great; if the only problem is dragging down the engine in the tough areas, charging may be the answer; any other problems, I guess you saved the trouble adding the charger to find out the hardway......dang forget the last part....the only thing more fun than your success would be pictures of your "failure!" /forums/images/graemlins/grin.gif

 

[Pooh_Bear]

Re: 5\' or bigger implements by Compact Tractors?

Wouldn't adding that extra 20% hp be overkill since I can
already spin the wheels of my 8n with the hp it has.

Keep in mind that I have a limited experience with tractors.
I have an 8n and have driven a ford 3000.
So if you are talking about larger tractors you have already lost me.
I am thinking of all this from the point of view of a 1949 8N tractor.

And everything I know about turbocharging comes from those
TV shows Trucks and HorsePower TV.

I believe my original questions was
what are you wanting to pull and how big is it.
And what are you wanting to pull it with.

Pooh Bear

 

[Soundguy]

Re: 5\' or bigger implements by Compact Tractors?

</font><font color="blue" class="small">( Tractor's components (frames, etc) are designed according to this 20-30% tolerances.

Why not sized implements? Compact tractors are relatively much newer items than most of implements which have been manufactured according to 35-50 hp tractors. Instead of sizing implements, why not adding a turbocharger to your compacts )</font>

There is a big difference in being able to power up an implement, and being able to use it safely.

A ford 8n will power up a round baler on the pto.. when the bailer starts shaking.. the little 2500# 8n gets thrown all over the place fast.. very unsafe.. the smaller tractor does not have the weight to manage the towed powered load.

There are many examples of where a higher pto hp might work.. gen sets.. chippers.. etc. However.. there are probably more situations where the extra hp is more or less moot due to not being able to use it safely.. either due to a traction or weight issue ( similar issues ).

Same reason why a 25 hp sear lawnmower can be towed around all day by a 17 hp scut. The 25hp lawnmower may be back there happilly spinning wheels.. but the 17 hp tractor is going to death drag it all over the pasture.. the weight is a huge factor in the tractor, and hp effectively transfered to the ground.

Soundguy

 

[TMcD_in_MI]

Re: 5\' or bigger implements by Compact Tractors?

</font><font color="blue" class="small">( Open or closed system doesn't matter.
Cooler air is always more dense for the same pressure.

Nomad sez: You have a contradiction. Not always so. If the air is in a rigid box (constant volume), pressure will not be same. )</font>

Nomad - I think you were a little too quick to jump on Pooh Bear's statement. He's right. His premise was that we have two samples of air at 'the same pressure'. In your closed box, you've heated the air and changed the pressure, so what happens in there doesn't refute his statement. Take a volume of air at 25 deg C and 1 atm pressure and compare it to any other volume of air at 0 deg C and 1 atm pressure. The cooler air will always have a higher density. Right? /forums/images/graemlins/smile.gif

Regards,
Tom