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Two-stroke engines offer twice as many power strokes for a given number of rotations and pistons by doing the exhaust and intake simultaneously. This normally happens spanning the end of the power stroke and the beginning of the compression stroke, though ideally it would only steal time from the beginning of the compression stroke. By tradition, nearly all two-stroke engines use a carburetor and are lubricated by oil being mixed into the fuel. The problem is pollution: unburned fuel passes right through the cylinder because the intake and exhaust valves open together, and this is made much worse by having the fuel be about 2% to 3% lubricating oil.
KTM fixes this for their two-stroke motorcycles by adding fuel injection. KTM injects into the transfer port, which isn't as good as injecting directly into the compression chamber but should still be a huge improvement. Honda has also filed a patent for a general purpose two-stroke with fuel injection. If one of them simply adds a normal oil pump, many of the problems of two-stroke pollution and annoyance should be gone. Next up, we need this small enough for chainsaws and weed cutters.
(Score: 2) by richtopia on Tuesday March 21 2017, @05:27PM (1 child)
For the most part I agree; I have corded electric appliances for everything in my 30'x100' yard. It bothers me every weekend when I can hear the neighbors' lawn equipment - not that electric is silent but it is quiet enough to not require hearing protection. And after using my little SunJoe that I can lift one handed, it is such a pleasure even with the annoying extension cord.
The other concern is pollution, mentioned in the article. Small engines have very little controls on emissions, so statistics such as "one hour of mowing grass equates 100 miles driven" exist (citation needed). From the article it sounds like including EFI will really help with pollution.
(Score: 0) by Anonymous Coward on Tuesday March 21 2017, @07:16PM
Typical houses are that size, sitting on a lot that is several times larger. On my street, lots probably vary from about 0.4 to 0.8 acres. Most are forested. One person has an oak forest. Mine is mostly palm trees. Some are umbrella trees and strangler figs and other jungle things.
The problem starts with needing a 200-foot extension cord. You could use a generator of course. :-)
I cut down coconut trees. They are fat at the base, perhaps 2.5 feet. I cut down oak trees about 14 inches thick. All of this needs to be chopped up. Then new trees sprout.
At $200 for a small tree or $500 for a large tree, doing things myself is way more affordable.
I try to save on pollution by not mowing. Once I let the lawn grow to 8 feet tall (weird clumping "grass" almost like bamboo) and got scolded by the county. Grrrr, how will I hide an airboat or a rusty pickup truck up on blocks? Damn government.