News for hackers. Stuff that matters.

A comment on China’s $4k electric cars tap huge market Tesla can’t reach. Parent comment

Re:China’s $4k electric cars tap huge market Tesla can’t reach by gene_kreemers on Saturday March 13, 2021 @03:53AM (#26445115)
Unfortunately you can’t turbocharge or supercharge a two-stroke. There’s a material amount of time during the cycle where both intake and exhaust port are open at the same time. If you use any type of forced induction it would blow the fuel/air mixture straight out the cylinder before it could be ignited. You can however use a tuned pipe to cause a pressure wave to reflect back up the pipe and compress the mixture, but that’s usually limited to a pretty narrow powerband
[ Parent | on HN ]
Re:China’s $4k electric cars tap huge market Tesla can’t reach by swimfar on Saturday March 13, 2021 @01:52PM (#26448889)
You can have forced induction with two-strokes if you use direct injection. It ends up being pretty efficient because you can blow all the exhaust out of the cylinders and have clean air for the next cycle. You also don't need to add oil to the fuel because you don't use the crankcase to pressurize the air/fuel charge. This type of engine is really common in construction equipment and (older) big trucks, semis, buses, etc. Some were even supercharged and turbocharged.
[ Parent | on HN ]
Re:China’s $4k electric cars tap huge market Tesla can’t reach by seryoiupfurds on Saturday March 13, 2021 @04:01PM (#26449956)
In fact, I believe the supercharger is necessary for them to function.

https://en.wikipedia.org/wiki/Two-stroke_diesel_engine

[ Parent | on HN ]
Re:China’s $4k electric cars tap huge market Tesla can’t reach by rsj_hn on Saturday March 13, 2021 @04:54AM (#26445425)
Ahh, so the special regs only apply to 2 strokes? I thought they were based on displacement
[ Parent | on HN ]
Re:China’s $4k electric cars tap huge market Tesla can’t reach by foepys on Saturday March 13, 2021 @07:36AM (#26446155)
They're also valid for 4 strokes but generally speaking 4-strokes have lower torque at high rpm and since it's hard to get much power out of 50ccm anyways, they tend to be 2-stroke.
[ Parent | on HN ]
Re:China’s $4k electric cars tap huge market Tesla can’t reach by rsj_hn on Sunday March 14, 2021 @06:08AM (#26454056)
I remember Honda made waves with low displacement four stroke engines.

https://en.wikipedia.org/wiki/Honda_CB50 https://en.wikipedia.org/wiki/Honda_Super_Cub

[ Parent | on HN ]
Re:China’s $4k electric cars tap huge market Tesla can’t reach by numpad0 on Saturday March 13, 2021 @12:22PM (#26448055)
I think he’s talking inherent technical limitations, not regulations. I wonder if it still applies if there was a pre-burning occurring in the middle of intake manifolds
[ Parent | on HN ]