Determining Linear Frequency: Velocity, Stroke & More

[cgaday]

How would you go about determening a linear frequency, compared to that of a rotational frequency. For instance, determining the frequency of a piston in cylcles/second?

I would assume velocity has to be involved, and the length of the stroke. How is velocity put into play, is it constant, or does it go in one direction, stop at 0 velocity, and then immediatly speed back up. Thats what it would do in the engine, but how do you account for this?

Help please!

 

[Lok]

A lfrequency is just that, the number of cycles ( oscilations, rotations or more complex motions) per second. If a piston starts at a position, then moves and comes back again to it's starting position then it completed a cycle.

If you consider the fact that piston stokes can be mechanically converted to rotations then it is very easy to understand the concept. Like in a crankshaft and connecting rod, where an engine has the same frecquency for the piston as for the crankshaft.

 

[cgaday]

Ah hah, thinking too complicated gets the best of me again. Essentially the piston would have the same frequency as the RPM's that the engine is undergoing correct?

 

[Lok]

Ah hah, thinking too complicated gets the best of me again. Essentially the piston would have the same frequency as the RPM's that the engine is undergoing correct?

Yes, the engines RPM is the number of cycles(rotations) / minute of the crankshaft, which is the same RPM ( although no rotation this time) of the piston. Speed does not matter as for the same frequency to pistons can travel 2 different paths (one longer one shorter) and still have the same rpm.

 

[sardar]

Determining a linear frequency, compared to a rotational frequency, involves understanding the difference between linear motion and rotational motion. Linear motion is movement in a straight line, while rotational motion is movement around an axis or center point.

To determine the frequency of a piston in cycles/second, we first need to measure the linear velocity of the piston. This can be done by measuring the distance the piston travels in a given time interval. The length of the stroke, or the distance the piston travels in one direction, is also important in determining the linear frequency.

Once we have the linear velocity and stroke length, we can calculate the frequency using the formula: frequency = linear velocity / stroke length. This will give us the linear frequency of the piston in cycles/second.

To compare this to a rotational frequency, we need to understand the relationship between linear and rotational motion. In a piston engine, the linear motion of the piston is converted into rotational motion of the crankshaft. The frequency of the crankshaft will be the same as the linear frequency of the piston, since every time the piston completes a cycle, the crankshaft also completes one rotation.

To determine the frequency of the crankshaft, we can measure the rotational velocity using a tachometer and then divide by 360 degrees (or 2π radians) to get the frequency in cycles/second.

In summary, to determine the linear frequency of a piston in cycles/second, we need to measure the linear velocity and stroke length. To compare this to the rotational frequency, we can measure the rotational velocity of the crankshaft and convert it to cycles/second. It is important to keep in mind the relationship between linear and rotational motion in order to accurately determine the frequency of a piston in an engine.