It goes to show that nothing beats displacement

[Nick R]

Originally Posted By: engineerscott
Originally Posted By: Nick R
I do think personally that lawnmowers have stagnated. I mean seriously, they pollute worse than any car engine out there these days, due to lack of cat, and emission control. They are extremely inefficient, with carbeurator, most with L-head engines.

I mean, it can't be that expensive to at least make an OHV engine, with basic electronic fuel injection, and a small cat. Eh, pipe dream probably.


Prove to me that their emissions are a problem first. And not as a percentage of total emission - it is true that OPE emissions have risen as a percentage of total internal combustion engine emissions, but that's only because auto emissions have been going down so rapidly. As a percentage they are still small. I think you are going after some rapidly diminishing returns when you start going after OPE, especially in light of the cost.

Of course, we do have OHV engines readily available for OPE.


Did you know that operating a traditional lawnmower for 1 hour releases more pollutans than driving a 1992 model year car for 500 miles? (read that somewhere a few years back)

 

[Shannow]

If you are going to push a mower, then L-head makes sense, rather than adding timing chains, pushrods, etc adding to the weight and complexity, not to mention complicating the oil system to include multiple lubricant compartments on a vertical crank arrangement, operated on variable, and quite steep grades.

Plus nobody is likely to pay a couple of grand to add dry sumping and EFI to it.

As to emissions, unless every mower owner is pushing their mower down Broadway during peak hour, that argument holds water...but to have a mower, implies that you aren't mowing Broadway in peak hour, but a space, in a non rush hour, and usually during the hot/dry season, where a bit of CO and NOx aren't really going to blanket the neighbourhood in photochemical smog.

 

[Shannow]

I'm wanting to find an old B and S mower and run it on wood gas.

My experiments with wood gas camp stoves is going well...need to find an older one sans plastic.

 

[eljefino]

Originally Posted By: Nick R


Did you know that operating a traditional lawnmower for 1 hour releases more pollutans than driving a 1992 model year car for 500 miles? (read that somewhere a few years back)


That would be naming one pollutant, my guess would be CO or HC from slightly incomplete combustion that a catco swallows. It would not be CO2. It would be the "worst case scenario" pollutant that could be measured, by someone looking to start a guilt trip.

A cat would be the easiest thing to add to a lawnmower; I can get a universal car one for $50 so a "mufflerlyst" should be about $5. Fuel injection is not really needed for something that runs a constant speed, but as said above it would be hard having a feedback fuel system without electricity to run a computer. My prototype would probably involve exhaust temperature (lean=hotter) affecting a bimetallic strip that then opens an air bleed by the carb.

 

[Klutch9]

Originally Posted By: OtisBlkR1
Originally Posted By: bepperb
I disagree. When it comes to push mowers, small displacement forced induction is the only way to go.


OK, you had me googling to see if such a production machine was made. As i couldnt find anything i am going to assume you just being silly (probably a tuner guy) right ?

If there was such a animal.. id love to play with a turbo lawnmower.. that would be a hoot !


Can you imagine all the tuner kids (and myself) fitting their parents' turbo lawn mowers with blow-off valves?

 

[TFB1]

Originally Posted By: Klutch9

Can you imagine all the tuner kids (and myself) fitting their parents' turbo lawn mowers with blow-off valves?

Or all the blown engines from disconnecting the wastegate???

 

[TFB1]

Since this is getting silly...

How 'bout a shot of NAWSSSS???!!!

 

[grcmptrnrd]

small engine EFI does exist: http://robinamerica.com/pfeatures.aspx?pid=226 It is sold at HomeDepot on a Ridgid pressure washer.

 

[Quest]

Originally Posted By: grcmptrnrd
small engine EFI does exist: http://robinamerica.com/pfeatures.aspx?pid=226 It is sold at HomeDepot on a Ridgid pressure washer.


I want one!

Q.

 

[meep]

What about using gear drive? All of these problems came about since blade tip speeds limit the rpm of these engines below their peak.

Run that small honda or kawasaki at 4400 rpm with a reduction to 2500 at the blade. Smaller displacement, smaller engine (lightweight!) keep it in it's natural sweetspot, easier starting.... could be pretty cool.

M

 

[Quest]

Originally Posted By: meep
What about using gear drive? All of these problems came about since blade tip speeds limit the rpm of these engines below their peak.

Run that small honda or kawasaki at 4400 rpm with a reduction to 2500 at the blade. Smaller displacement, smaller engine (lightweight!) keep it in it's natural sweetspot, easier starting.... could be pretty cool.

M
gear reduction drive makes good sense (lower rpm in exchange for higher torque.

trouble are 2 fold:

(a ) additional cost. Most lawnmower/small engine manufacturers are on a razor-thin margin and they don't see the need of the additional cost/complexity of adding gear reduction box to the engine.

(b )generally dumbb-down avg joes out there, which some of them doesn't even maintain/know how to deal with small engines (even the most mundane/basic stuff), letting alone adding a reduction gear drive to it.

My 2'cs worth.

Q.

 

[SteveSRT8]

Added cost/weight could be very small, low power means tiny gears. Synthetic sealed oil for zero maintenance. It could be cheap and trouble free.

Might be able to use smaller engines to save money and weight.

 

[ac_tc]

The gears cant be dimensioned for the engine out put.
They have to dimensioned for blade hitting stone ,pipe etc
and effectively stopping rotation directly...
The could of course add some slip type clutch but then
whe have the problem of cost and parts growing.
A v type belt would solve this but now you a belt that worns out.

 

[meep]

Perhaps if the gearset were internal, not hard to do, (how many fwd chaindrive PTO's do you recall?) at least the maint would be taken care of. lighter weight crank, rotating parts to reduce "stump stress." hardest part would be maintaining a strong spindle for the blade--- a basic saddle mount would tear off.

I would like my next mower to be a wankel rotary.

M