Finally got time to read a bit of the patent, which talks about two TDCs and BDCs, which I'll denote as "high" and "low", as related to the distance of the pist

Finally got time to read a bit of the patent, which talks about two TDCs and BDCs, which I'll denote as "high" and "low", as related to the distance of the piston to the crankshaft. So the high TDC has maximum compression, and low BDC has the maximum cylinder volume, and the scavenging port(s) are between high BDC and low BDC. Unless I screwed up my notation shift, the strokes from the patent are as follows: 1. Intake (low TDC -> high BDC) 2. Compression (high BDC -> high TDC) 3. Power (high TDC -> low BDC) 4. Compression (low BDC -> high TDC) 5. Power (high TDC -> high BDC) 6. Exhaust (high BDC -> low BDC) So during the first power stroke, stroke 3, the cylinder moves from "high" to "low" and thus is the longer power stroke. Also during the second compression stroke, stroke 4, the cylinder position moves from "low" to "high". So technically leading to higher compression ratio. I was thinking it would cost too much energy to do so, hence dismissed that alternative, but I guess not. The patent also notes that the extra scavenging ports are not needed, fresh air-fuel mixture can be introduced via the inlet valve(s) while the piston moves between the two BDCs. Would be fun to try to simulate it in Ange's engine simulator[1]. [1]: https://github.com/ange-yaghi/engine-sim https://github.com/ange-yaghi/engine-sim