Question by jerry pace: Creating a new piston compression using magnetic pulses firing the engine ?
Old petrol engines use petrol to create an explosion in the bore to push the piston down but using a magnetic pulse instead of petrol to push a piston down to run a old petrol engine .New cylinder heads, pistons and bore liners can be inserted into a petrol engine to run it on magnetic compression but a long wind starter in needed to turn the engine at running speed to start it and a series of high voltage alternators to deliver electricity to run the electric pulses to create compression what is your opinion?
Best answer:
Answer by SA-4-EVA
Engine casings are completely metallic. That said, the magnetic interference would cause the pistons to stick to the casing, and there would be little/no movement. Perhaps as a brand new engine using an insulating material instead of just replacing the heads and pistons would work for that part.
But then comes the question of the energy source. A petrol engine uses the thermodynamic properties of air along with the combustion of a fuel-air mixture to drive the compression/expansion cycles. Using magnetic repulsions *could* work, but honestly, why not just use a DC engine, and get more torque and efficiency out of the entire thing?
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2 Responses
Sounds like a extremely inefficient way to make an electric motor even if you have magnetic pistons that are repelled by fixed position pulsed electromagnets in your redesigned heads. The force that two magnetic fields exert on each other falls off rapidly as the distance between them increases. Fields associated with adjacent pistons within the shared block will also have an effect on each other. The efficiency of your old petrol engine will look absolutely “green” by comparison.
Where are you going to get the energy to run your alternators?
Don
I am sure that a motor, pump, compressor device – something like this has been made before. You could make a related machine with a solenoid coupled to a piston in a cylinder (or a diaphragm) easily enough. Look up “solenoid pump” and you will find them. The electrical pulses to the solenoid are synchronised to the piston position in some way. A solenoid (or a related reciprocating electrical device) is another form of an electric motor.
The problem with this arrangement is getting a high efficiency. Long ago it was discovered that the gap in the core between the armature and field of an electric motor must be very small for good efficiency. Thus there are electric motors using rotating parts that are as high as 98% efficient at converting electrical power to mechanical power. This is because the design can have very small gaps. The reason solenoid pumps exist is because they are relatively simple (one moving part in some cases) so inefficiency is not the only issue. An air pump in a fish tank is an electric pump closely related to your idea. It is synchronised by mechanical resonance.
Your idea is a good start along the road to invention, but the method of implementation needs more refinement. Also it looks like you are talking about some sort of self powering device, which has long been known as extremely unlikely (to say it gently). This is usually called perpetual motion, and implies that a machine can be made that not only has no losses, but magically generates power without using energy. Machines convert one form of energy to another, with inherent losses in the process. The “lost” energy is eventually released as other forms of energy like heat. Your machine seems to be the idea of a reciprocating motor coupled to a reciprocating generator, so that it “perpetuates its own operation”. While the generator feeds back some energy, the losses throughout the machine are such that it will rapidly come to a halt, and this will happen even more quickly if there is power taken out (in the form of compressed air). It is the equivalent of a flywheel. Consider 90% of 90% of 90% etc and you will see that the energy drops rapidly even with good but practically achievable efficiencies. Try plotting the curve of cycles (or time) versus remaining energy.