Piston Force Graphs: Manipulating Parameters in Combustion Pistons

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Graphs of Piston Force versus Piston Displacement or time in combustion pistons can be influenced by various parameters, including fuel and air amounts, piston geometry, and RPM. The highest force on the piston occurs at top dead center (TDC) during the overlap position. Lighter pistons allow for higher RPMs and reduce the weight of connecting rods, impacting performance. Drag racers prefer lighter components for faster revs, while NASCAR engines often utilize rod ratios closer to theoretical ideals for power efficiency. For further insights, users are encouraged to explore existing discussions on piston force in mechanical engineering forums.
physea
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Hello guys!
Can I view graphs of Piston Force versus Piston Displacement or time, in a combustion piston?
I would be interested to see how the graph varies by manipulating parameters such as fuel amount, air amount, piston geometry, rpm, etc
Thanks!
 
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hmm I can tell you that the highest force on the piston is at tdc in the overlap position. The less the piston weighs the higher rpm you can run. The less the piston weighs the less the connecting rod has to weigh. You would think rod angle is the limiting factor in rod ratio/ stroke. The 900 cubic inch pro mod engines have a rod ratio/ angle that you think would not work. (1.3 lol) They use a 11.1 inch deck height A 5.5 inch stroke. A 7.250 long connecting rod. and a 5.1 inch bore. red line is about 8000 lol rpm If you look at the rod angle you would think the piston would go through the side of the block- it does when you make a mistake.The biggest drag/ load are the valve springs. They are maybe 500 lbs on the seat- 1200 lbs on the nose x 16 x 8000 rpm. I think net lift is now 1.2 inches. NASCAR engines like to run close to the theoretical rod ratio 1.83? There is an argument over whether the lighter weight let's the engine rev faster or whether the longer rod/ higher ratio make more power. The drag racers go with lighter. NASCAR goes with rod ratios closer to ideal. If you do the load versus weight cals. you will see why light weight pistons are most important.
 

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