Recent content by novaguy

I don't think I cherry picked anything. So far, there is mostly conjecture on whether or not reciprocating inertia increases power. Just people stating off the top of their heads what they think. What I've found though various studies and my own data is that lower piston mass does increase...

You conveniently left out the conclusion by the NREL study showing piston mass to increase MEP. "A study by the National Renewable Energy Laboratory (NREL) found that reducing the mass of the pistons in a spark-ignition engine improved the engine's thermal efficiency by up to 3%. This was...

So, I decided to ask ChatGPT what it thought about the subject 😁 Here is probably the real mechanism behind it, which explains my thinking: lower piston mass can increase the mean effective pressure of the engine. Reciprocating Inertia: Reducing the mass of the pistons can decrease the...

Nothing revolutionary but gave some nice equations of motion to plug into with my engine geometry/mass. Attached is a PDF copy of the paper: Hailemariam Nigus. Kinematics and Load Formulation of Engine Crank Mechanism. Mechanics, Materials Science & Engineering Journal, 2015...

Can we agree that lower piston mass will reduce the torque due to inertia? Can we also agree that the torque resulting from gas expansion is equal for each engine (one with a lighter piston, the other stock)? And that the total torque generated (not including resistive torques for...

I went ahead and plotted these using the actual engine geometry and an assumed gas pressure of 300 psi. Torque due to reciprocating inertia (piston and con-rod): Keep in mind, a realistic plot of combustion would be phase shifted and have a sharper peak. However, this does show the...

Can someone tell me if this is wrong mathematically? The equivalent mass of the reciprocating components MREC (piston and some proportion of the connecting rod) will be reduced by a small amount, due to the piston mass being 33% less. FI=MREC*AREC The Inertial Force, FI will DECREASE with a...

It's really just an experiment to see if a generative designed (consumer grade software) piston can be printed without proprietary alloys (unlike Porsche/Mahle who have done this exact thing in the GT2 RS) and work for a "while". No modifications will be done besides the piston swap. I...

I should've mentioned from the outset that this piston will be run in a test stand. It will be compared directly with the stock piston in this setup. In this case the engine won't be under load so drivetrain inertia, drag force, rolling resistance are not factors. Purely looking at the engine...

Surely there must be worse somewhere in history - it should've been obvious the acceleration of a mean speed is ZERO but not when I cobbled that together. You don't have to be a da(t)/dt about it lol. So, the answer I am seeing so far is: With lower piston mass, less energy is required from...

At steady state RPM the engine speed isn't changing so the angular acceleration is zero, but the piston is changing speed? Maybe I'm wrong

The combustion pressure (and power created from it) is not increasing of course, that power created is the same regardless of piston mass. The power that is no longer being "robbed" to move the piston is what I'm wondering about. In my calculations, the power used to move the piston mass goes...

The lower piston reciprocating mass means the connecting rod and crankshaft do less work to propel the piston. With less energy being lost to moving the piston, doesn't that mean the crank and flywheel can release energy faster? Rate of work done = power

Lower piston mass means it takes less force to accelerate. F=ma Less force over the course of the engine stroke means less work wasted W=fd Shouldn't this equate to more work output from the crank and flywheel?

With lower piston mass, less work has to be done. At 11,000 rpm the piston is accelerating to and from a stop 22,000 times a minute! I imagine this must have some theoretical effect. If less work is done to move the piston, does the crankshaft and flywheel accelerate faster, increasing the rate...