Diesel lawn mowers? Why none

[Welshbeef]

Diesels make great sense for say locomotives cement mixers but why not lawnmowers? Same revs all the time lots of torque needed.

Then the hassle of ignition system going wrong vs a compression engine which should last forever.
I don't think petrolmowers sound very nice and don't doubt a diesel mower would be barely better than a cement mixer noise wise.

So why not? It's the cheaper and more long term durability

[anonymous-user]

Petrol lawn mowers sound great, if you take the exhaust off and make a nice exhaust system for it.

Take the govenour off and rev it as much as you dare!

[McSam]

It's not really cheaper. They need buggerall torque, and the inherently heavier design of a diesel engine wouldn't really be good for something you've got to shove around your garden all afternoon!

[paulmoonraker]

McSam said:

It's not really cheaper. They need buggerall torque, and the inherently heavier design of a diesel engine wouldn't really be good for something you've got to shove around your garden all afternoon!

Imagine though, a 330d lawn mower that had been mapped... Complete with iMow ...

[GroundEffect]

Because it's totally not necessary. Mowers need very little torque and are never run for that long. And then you have the whole issue of diesel engines costing more and weighing more. Not a sensible idea.

[Welshbeef]

McSam said:

It's not really cheaper. They need buggerall torque, and the inherently heavier design of a diesel engine wouldn't really be good for something you've got to shove around your garden all afternoon!

I burn out electric motors... Long grass very wet smash through it full power. Used to do that with my old mans mountfield petrol he cursed me I ruined it so many times in the end he bought a Honda and no matter what length or wetness it just smashed through the engine didn't even strain just maintained revs a great machine but pricy.


I see your point re weight.
But to have the diesel cut the lawn at idle vs a petrol at rabbit full revs would be better all round.

[slipstream 1985]

yeah but think of the time saved from not having to refuel. the mpg must be through the roof.

[TheEnd]

Battery start would make them heavy, hand start would be a real struggle.

[Mr2Mike]

Welshbeef said:

I see your point re weight.
But to have the diesel cut the lawn at idle vs a petrol at rabbit full revs would be better all round.

You'd still need the same RPM for a rotary mower, since the blade is attached to the end of the crank. I reckon a diesel engine would cost at least twice what a petrol does to manufacture, possibly quite a bit more.

As for the whole "torque" thing, normally aspirated diesel engines are hardly endowed with an abundance of the stuff. They tend to have somewhat less then the equivalent capacity petrol engine in fact. e.g. VAG 1.9 SDi, peak torque 98 lbft. Even a mediocre 2.0L petrol engine would have at 20-30% more, a decent one maybe 50% more.

[Welshbeef]

TheEnd said:

Battery start would make them heavy, hand start would be a real struggle.

How about a detachable battery??

Mpg on a mower is important I hated filling up jerry cans at the fuel pumps. As in less wasted time doing chores.

[roofer]

You'd need an exhaust vac for the soot....hmmmmmm, black striped grass anyone.

[anonymous-user]

you know how hard it is to start that old mower thats sat in the shed for 8months when it's cold? Now imagine that with a heavy fuel engine with a static compression ratio of twice the petrol engine!


(and besides, ultimte fuel economy is irrelevent for mowers (just fit a slightly larger tank etc) and because the engines are small capacity, they actually operate close to WOT anywhere where diesels have little improvement over petrol engines) and rotarty mowers are typically "high speed" machines (they rely on whirling a pretty blunt blade around at high rpm) so suit a petrol engines higher "power density" more.

In actually fact, as soon as you get into "Industrial mowers" like the council use, they are actually all diesel these days!!

[paulmoonraker]

You are all missing the point... A 330d powered mower would be the answer!

[Simpo Two]

Power to weight ratio I expect. Plus a lawnmower needs rpm not torque.

[Welshbeef]

Simpo Two said:

Power to weight ratio I expect. Plus a lawnmower needs rpm not torque.

I'm looking at possibly 24" cut.
As for rpm a gearing could provide that from a diesel. But yep adding weight cost complexity doesnt make much sense.

[renmure]

My big one is Diesel, the wee one is petrol.

[eldar]

Welshbeef said:

I'm looking at possibly 24" cut.
As for rpm a gearing could provide that from a diesel. But yep adding weight cost complexity doesnt make much sense.

True. V8 sounds kind of unlawnmowery.

http://www.youtube.com/watch?v=Suid63Hsdxg

[thinfourth2]

Diesel ride-on mowers are the norm once you get over the cack they sell in B&Q.

As to push mowers i've never seen a diesel as a rotary but I am sure i have seen a cylinder one for bowling greens etc

[TheEnd]

Sometimes the weight can be an advantage if it is going to have a roller fitted too, but generally petrol engines are easier to start on a pull cord, cheaper and lighter, so most just use one of those little Honda petrol engines for simplicity.

[dave_s13]

We have an old derv wacker plate in the family somewhere. I've borrowed it a couple of times and by christ, what an utter bastd it is to get going. You have to pull it about 60 times, and time the pull just right or you meet resistance and it yanks your arm out.

Great once it got going though, and it was filled up sometime in 1963; not needed a top up as yet.