# How to measure the torque of a compressed air engine?

In summary: Is it a 4 stroke engine that has the cam altered to provide two inlet valves (after every compression stroke)? If so, that would be exceedingly rare. Or is it a two stroke engine that has the cam altered to provide two exhaust valves (after every two compression strokes)? The engine you are describing is not a double acting engine. A double acting engine is one that has the cam altered to provide two inlet valves (after every compression stroke) or two exhaust valves (after every two compression strokes). A two stroke engine does not have a cam that alters the inlet or exhaust valves.
Summary: The main idea of my graduation project is to convert the motorcycle engine to work on compressed air that come from a 180 L tank (10 bar compressed air inside the tank )
I have some problems to how calculate the required torque to move the cart .

The main idea of my graduation project is to convert the motorcycle engine (single cylinder and double acting ) to work on a compressed air that comes from a 180 L tank (10 bar compressed air inside the tank ) , I have some problems to how calculate the required torque to move the cart roughly (200 kg ) with supply air to push the piston at 6 bar . I used pneumatic cylinder (50 mm stroke , 63 mm diameter ) .
Please help me to measure the torque required and the output torque of the engine with these data !
Thanks a lot

Last edited by a moderator:
Welcome to the PF.

I've moved your thread to the schoolwork forums. Please show us your initial design for this. And what do you mean by a "double acting" motorcycle engine? It sounds like you are wanting to substitute a "pneumatic cylinder" for the motorcycle engine? What are you going to use for the gearing/transmission?

This engine is really double acting? Are you sure? That would be exceedingly rare in an IC engine.

Tom.G
Unless it is a word hash for a two cycle engine ( a two stroke engine ).

Unless it is a word hash for a two cycle engine ( a two stroke engine ).

"Two stroke" and "double acting" are well defined concepts, and any confusion shows that the speaker is in over his/her head.

Double acting could be a 4 stroke engine that has the cam altered to provide to inlet after every compression stroke. The cam is altered to open the inlet valve when piston is top dead centre and to open the exhaust valve when the piston is rising in the cylinder. Lots of YouTube videos showing people converting four stroke ic engines to 2 stroke steam or air engines.

The term double acting means that positive pressure acts on both sides of the piston. This requires the ability to seal the around the piston rod, a requirement that cannot be met with the simple slider-crank. It was done in the steam engine era, and today in some gas compressors, by the use of a crosshead assembly. This adds considerable complexity and inertia to the whole system, and as with any seal system, is subject to leakage.

Cam alterations can do nothing to make a simple slider-crank serve as a double acting machine.

berkeman
That’s why the question is what is meant by double acting.

## 1. How do I measure the torque of a compressed air engine?

To measure the torque of a compressed air engine, you will need a torque meter or a dynamometer. These tools can be attached to the engine's output shaft to measure the rotational force produced by the engine.

## 2. What is the unit of measurement for torque?

Torque is typically measured in Newton-meters (Nm) or foot-pounds (ft-lb). However, some torque meters may also display measurements in other units such as kilogram-meters (kg-m) or inch-pounds (in-lb).

## 3. Can I calculate the torque of a compressed air engine using other measurements?

Yes, you can calculate torque by multiplying the force applied to the engine's output shaft by the distance from the center of the shaft to the point of application of the force. However, this method may not be as accurate as using a torque meter.

## 4. How can I ensure accurate torque measurements?

To ensure accurate torque measurements, it is important to properly calibrate your torque meter and make sure it is properly attached to the engine's output shaft. It is also important to take multiple measurements and calculate an average to reduce any potential errors.

## 5. Are there any safety precautions I should take when measuring torque?

Yes, it is important to follow all safety precautions when measuring torque, as the engine may be under high pressure and can cause injury if not handled properly. Make sure to wear appropriate protective gear and follow the manufacturer's instructions for using the torque meter.

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