Practical solution to variable compression

[Carter Hendricks]

At 09:52 AM 3/12/98 -0600, Matthew B. Watts wrote:
>
>> I was talking to my mate who has been working on engines
>> for about 30 years now, he told me about an 8 piston desiel
>> engine with 4 cylinder bores and two crankshafts.
>>The two pistons opposed each other and on the compression
>> stroke would move towards each other causing a masive
>> compression which would ignite the desiel and force the two
>> apart.

I once had someone interest me in building a small diesel engine 
for his sailboat, and I thought of opposed crankshafts--in fact
opposed 2 cycle motorcycle crankcases, which are ready-made.
Then he told me that the reason he wanted me to build an engine
for him is because the available commercial powerplants were
so expensive.  Oh, well...

>I was thinking about this while designing a model of a 200cc
>two stroke engine (single bore only) that uses opposing pistons...
>
>What if one tied the cranks together with a gear drive mechanism
>having a gear on each crank and a pair of idler gears coupled
>together 

Ing Busso's variable timing device, designed in what the mid-70's,
comes to mind...  Reverse splines and oil-driven plunger...  But
stressed for even a little motor? I don't know...

with a clutch that could only slip say, 15 degrees.  By
>effectively putting the two cranks out of exact synchronization,
>wouldn't you change the engine's compression?
>
>Think about it a minute.  If at exact alignment, the two pistons
>reach TDC at the same time, then you have MAX compression.

Another Alfa Romeo scheme I wanted to mention a couple weeks ago
was a factory V6 motor with different controls on each bank, three
cylinders naturally aspirated, high compression, the other three low
compression and turbocharged, and with individual turbos fed from 
each bank...  [NOT the crude/simple Callaway project].
 
                                                --Carter