Why do Diesel Engines require 2 valves?

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Some of you didn't understand the gnome monosoupape.

This engine has two valves per cylinder (if in doubt, read wikipedia first before answering).
1)the namegiving monosoupape, located at the top of the cylinder and controlled by a cam. Which is an poppetvalve type outlet.
2)the intakevalve, which is basically a hole located in the piston and opened by the suction caused by the piston on downward travel during induction stroke.
Rich mixture with lots of oil is sucked from the crankcase into the cylinder until the vaccum in the cylinder ceases and counterweights close the intakevalve.

As you can see, poweroutput is strongly limited by bad cylinder filling at high rpm, as the induction controlled valve will not open nor close at the right time.
 
Reliability was not an issue with Detroit 2 strokes. They made engines from 1 cylinder to 16 cylinder, all with interchangeable parts within a series, from about 1935 to about 2000. They made three series, 53 ci, 71ci an 92 ci per cylinder. They quit when they couldn't make the engines meet the new emission regulations. These were all intake port, exhaust valve configuration with a blower on the intake and some with an exhaust turbo as well.
 
Yes,

They were a great engine. There was some talk around the CAFE standard and Detroit 2 stroke using a turbo scavenge blower driven off the flywheel to try and comply. I guess it was not successful as they elected to go 4 stroke.

Best Regards
Bob
 
don't forget about the EMD's in the locomotives the big Detroit's,up to twenty cylinders and 710cid per cylinder ;D ;D
 
Those Detroit engines sure were noisy devils, too.

When they came out with the 4 cycle engines (60 Series) we always used to say that they were Detroit engines with the new converters on them. Someone would always ask "what new converters?" to which we would reply "the ones that convert noise into power". :big:
 

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