Happy medium between 2 and 4 stroke?

Here are some pictures of a 110cc opposed piston 4 stroke designed by Pinnacle:


1729324d1518325243t-greaves-cotton-auto-expo-2018-dsc_6518.jpg


1729325d1518325243t-greaves-cotton-auto-expo-2018-dsc_6519.jpg


1729326d1518325243t-greaves-cotton-auto-expo-2018-dsc_6520.jpg


According to the link it makes 7 HP @ 6500 rpm.

P.S. Here is a video with Pinnacle engines demonstrating how the sleeve valve works:


Looks like a nightmare on the inside. They'll never be able to produce an affordable version before battery tech advances just a little farther rendering the power to weight ratio of this engine obsolete.
 
According to this article (from 2013) the Pinnacle 110cc opposed piston 4 cycle sleeve valve engine was expected to be $25 more expensive to build than a conventional engine.


For the target market (the Asian scooter market), the low NOx capability of the Pinnacle engine provides a significant cost benefit to manufacturers. For such small vehicle applications, manufacturers are seeking a fuel-efficient means of reducing engine-out NOx to avoid the cost of implementing a 3-way catalyst and closed-loop-controlled fuel injection system.

While the Pinnacle 110cc engine is expected to cost about $25 more per unit to build than a current conventional engine, those engines are looking at an increased build expense of $75-$80 to add on the fuel injection system, lambda sensor and fuel pump controls required to meet emissions requirements, plus the cost of exhaust treatment, said Monty Cleeves, Pinnacle founder, President and CTO. When the entire vehicle costs around $700, that’s a significant difference.

......and according to the video below (from 2018) it doesn't need a 3-way catalytic converter to meet India's BS6 emissions (which I believe are ~equal to Euro VI emissions...correct me if I am wrong.)



It only needs a two way catalytic converter (i.e. oxidation catalytic converter converting CO and HC to CO2 and H20).
 
Last edited:
Variable compression ratio engine:

iu




I would only see this being useful for engines that use a turbo. If light on the foot you don't get boost so it's better to run high compression for fuel efficiency. When you floor it you are looking for power, the turbo spools up and you need a lower compression ratio to not blow your head off, let alone pre-detonate.
 
I would only see this being useful for engines that use a turbo. If light on the foot you don't get boost so it's better to run high compression for fuel efficiency. When you floor it you are looking for power, the turbo spools up and you need a lower compression ratio to not blow your head off, let alone pre-detonate.

Going beyond turbo usage two applications for variable compression ratio would be HCCI (Homogeneous charge compression ignition) and the other one is improved efficiency when using flex fuels like E85 (which has a lower energy density than gasoline but higher octane).
 
Back
Top