Another path for two-strokes_ kevin cameron’s top dead center _ cycle world gas 1940 hopper

Direct fuel injection (DFI), which could possibly have saved the two-stroke from being legislated off our highways, arrived too late to be useful. The problem with conventional two-strokes like the Yamaha RD350s and Kawasaki H2 750s of the past was that their cylinders were scavenged by air that had already picked up fuel from a carburetor. Gas in back With exhaust and transfer ports cut into the cylinder walls the exhaust and cylinder-filling processes overlap each other, allowing loss of some fuel out the exhaust port. F gas regulations r22 Even in the case of well-tuned racing engines, brake specific fuel consumption (BSFC) of a two-stroke, at .65 pound of fuel per horsepower per hour, is 30% greater than BSFC of a typical four-stroke, at .5 lb./hp-hr. Austin electricity outage Where does the extra 30% of fuel go? Out the exhaust port, to be detected with profound disapproval by the EPA. DFI fixes that.

Gas 47 cents Instead of blowing fuel-bearing carbureted air into the cylinder, we blow pure air. Gsa 2016 Then, as the rising piston closes the exhaust port, a fuel injector sprays in a mist of fast-evaporating small droplets of 10-30 micron size. O gascon Because the exhaust port is closed, zero fuel can be lost through it, so BSFC becomes as good as or better than that of four-strokes.

Gas leak in house Such DFI two-strokes, because they inherently have low emissions of NOx, are very attractive low-emissions powerplants. This benefit comes with problems.

Npower gas price per unit One is that there are only 60-70 crank degrees between exhaust closure and ignition, and in that time we have to get the fuel into the cylinder in the form of droplets much smaller than those produced by normal automotive fuel injectors (50 – 150 microns). Electricity videos for 4th grade Another approach, used by Bombardier in some snowmobile engines, is to inject the fuel not into the cylinder, but farther upstream, timed in such a way that the leading edge of the fuel mist cannot reach the exhaust before it closes. K electric share price This is termed ‘indirect’ injection.

Another problem is that we inherited the crankcase-scavenged two-stroke from a decision of the FIMN just after the war. Gas law questions and answers Having decided to ban supercharging from GP racing, they accepted crankcase scavenging because it nominally pumps only a volume of charge equal to cylinder displacement. Gas giants It is therefore not supercharging. Here’s how it works. Grade 6 electricity project As the piston rises, it creates a partial vacuum in the crankcase beneath it. Electricity facts label A valve – which can be a piston port, reed, or rotating disc – opens, allowing air to rush in through a carburetor to fill the crankcase.

2015 electricity rates This valve closes at some later time, trapping fuel-air mixture in the crankcase. Electricity sources in canada As the piston descends, it compresses this mixture so that when the piston uncovers the two or more transfer ports (so-called because they “transfer” mixture from crankcase to cylinder), the compressed mixture in the crankcase jets into the cylinder, refilling it and chasing out exhaust gas. Even this has problems, because with all that mixture passing through the crankcase, we can only use rolling bearings to support the crank and connecting-rods – bearings that can survive on very little oil. Electricity human body To lubricate them (sort of) we either mix oil into the fuel or inject oil from a metering pump.

Gas bike alley This lube oil does a marginal job of lubricating the bearings (which at racing speed operate pretty hot) and then it goes into the combustion chamber where most of it burns, producing smoke . Gas 2015 Yes, yes, we can use so-called smokeless oils, but this is really a Band-Aid on top of a Band-Aid. Gaslighting Either way, here are the lads and lasses of the EPA with their 5-gas analyzers, smoke density meters, and other gadgetry. R gas constant chemistry We are led away for trial.

Another problem is that when we try to make serious power, two-stroke pistons get really hot because these engines fire every time the piston approaches TDC, not every other time. Static electricity review worksheet So we have to cool the daylights out of the cylinder walls (race engines had to run coolant temps as low as 130F). When production DFI two-strokes were built, it was found that without the evaporative cooling of fuel passing through the crankcase, the case and all the rolling bearings in it ran a lot hotter than before. Zyklon b gas canister for sale Well, OK, we’ll core coolant passages in the cases to pull that heat out. Gas ark And now the engineers are talking about two-loop cooling systems – a low temp loop for cylinder walls and crankcase, and a hot loop for the head and exhaust-port region.

When in the early 1990s Ford evaluated DFI two-strokes as possible economy-car powerplants, a big concern was rusting of the all-roller bottom end, exposed as it was to possibly wet air and moisture from combustion. Electricity and magnetism worksheets You drive to the airport, park, and fly to Asia for a month of environmental conferences. 9gag instagram logo You come home to find your engine doesn’t turn? We got this every spring at our dealership – a stack of repair orders saying “Kickstart lever will not go down – get running.

” Those bikes wintered over chained to parking meters or left in unheated sheds. Why do it this hard way? Let’s start with a long-lasting four-stroke-type bottom end – plain bearing crank and rods lubricated by filtered, recirculating oil. E suvidha electricity bill lucknow This wipes out rusted lower ends and mixing oil with the fuel. Electricity year invented It also takes care of the piston cooling problem because now we can use piston cooling oil jets as other modern engines do. Gas and supply We no longer need to core the crankcase for coolant passages – the oil does that for us. Now we install normal water-cooled two-stroke cylinders, but with a difference. Electricity dance moms full episode Instead of the transfer ports leading down to the crankcase, each cylinder’s transfer ports are fed from a throttled air trunk that surrounds them.

Gas bloating pain Scavenge air to each cylinder’s throttle body is supplied by a rotary blower just as it is on GM two-stroke Diesels or on the giant marine two-stroke Diesels that carry world trade. Or, if we decide that having piston rings slide across exhaust ports is too shaky a proposition, we can do what Toyota did with their 6-cylinder prototype two-stroke of the early ‘90s; we can put four poppet exhaust valves in each head and have a 360-degree ring of fresh-charge ports that open near bottom center.

Electricity definition chemistry It won’t be easy to operate poppet valves at double-speed this way, so let’s say “some R&D required.” There has to be some reason why the world is not filled at present with Toyota trucks powered by stump-pulling two-stroke torquers.

This will be a DFI or indirect injection engine to keep fuel from going out the exhaust, so there will be the speed limitation of DFI injectors. Power outage houston zip code Last I heard, 10,000-rpm was the upper limit for the very fast voice-coil-driven injectors made under OMC license. O gastronomico Surely some progress has been made since then. The last of the racing two-stroke GP engines achieved cylinder-filling equal to or greater than that of racing four-strokes, and they did it at 13,000-rpm. Electricity outage chicago That gave us 55-hp 125s, 100-hp 250s, and 190-hp 500s (A crank for a Honda NSR500 was rumored to be $50,000). Electricity deregulation Let’s not be too ambitious, so let’s start with cylinder-filling only 80% as good as that, with a 10,000-rpm power peak that DFI might be able to handle.

Static electricity online games That would give a 1000-cc four 246-hp. Mm, there would be other problems. 76 gas credit card login To make this thing come on-throttle smoothly, rather than in traditional kick-that-tire-loose fashion, we’d have to put some R&D into dual-mode combustion – stratified-charge at low throttle to make the thing fire regularly, and homogeneous charge at larger throttle – while keeping emissions below legal maximums, of course. Well, you get the idea – this might all be possible, but somebody would have to come up with the R&D bucks to bring it all together – an outcome that wouldn’t be guaranteed. 1 unit electricity cost in andhra pradesh Back in the late ‘80s/early ‘90s there were 22 DFI legal emissions two-stroke research programs running that I counted, and pretty much all the auto majors were involved.

Electricity and circuits class 6 questions Yet no production engines resulted. Types of electricity consumers Everyone took the well-trodden path – four-strokes.