Muffler's Power Loss And Efficiency

Noise = Energy

Noise creation = Energy Conversion into unusable/un-desirable form = Loss of efficiency

Muffler - absorber of noise (active methods or more common- passive methods)

In either way it is not reducing the noise generation, only the noise emission into sorrounding.

Theoritically speaking mufflers should decrease efficiency may be by negligible amount by its action.

Though I guess it might have some positive effect by reducing the shock waves at the engine exhaust which may affect engine performance.

Total exhaust system length, number and severity of bends and diameter will also affect back pressure. Back pressure should be as low as practical.

Most modern exhaust systems do a good job from the factory.

And, catalytic converters create far more back pressure than mufflers, if your car has one.

Exhaust systems are a science.

There are tradeoffs with the design. Basically, consider the factors involved; dB sound pressure, emissions, power loss, exhaust temperature, restriction of exhaust gasses, and the physical space that the system must fit into.

Although this is not exact, imagine a circle with all of those attributes evenly distributed along the perimeter. Now place a dot toward any one of those attributes that you desire inside the circle. The closer you get to one attribute the more the others will suffer.

Everything is a series of compromises that the designer must take into consideration. What is desirable for a race car is not the ideal for a family sedan.

Dear Hero I think that I have to tell you better about my interest in mufflers: A friend of mine who is an amateur ornitologist needs a power supply for many hours in a remote site, a battery will not be sufficient, so I thought about a small generator[about 500w], but the problem is with the noise! So I thought that a good muffler will solve the problem . Is it possible to reduce the noise about 90% from the unmuffled engine? And if yes, will it cause some other problems? kind regards, and thanks in advance. azi

You need one of those hon-da generators. They were really, really quiet.

No chance of going solar or inverter with such a low power requirement? After all it is only 0.5KW

What kind of inverter? It will be use most of the time at night.

What I meant Tornado spoke out loudly, or rather not so loud _{(he didn't capitalize)}

Yes, the problem is the weight of the batteries, the guy has to carry this on his back, climbing hills,and he has some more load to carry.this is the reason for my questions.

Yes weight will be a problem. Even with the best (or rather second best Li Ions) @approx 200 Wh/Kg it will be 20 Kgs. Li-Sulpher may be lighter (half the weight) but then it has low life and is still not that stabilised. So this will for all practical purposes rule the rechargeables out.

I hate to repeat myself, but Honda (not an endorsement) offers this for under $1,000.00USD. I'm sure there are others, too.

• 1000 watts (8.3 A) of Honda inverter 120V AC power
• Super quiet - 53 to 59 dB(A)
• Lightweight (less than 29 lbs. !!)
• Eco-Throttle - runs up to 8.3 hr on 0.6 gal. of fuel
• Advanced inverter technology provides reliable power to computers and other sensitive equipment
• 12V - 8A DC output

Thank you very much! In hebrew:Toda Raba

Before dismissing batteries altogether, what if the average load is, say, 360w? With a 12v battery, this would be 30a. If it runs 10 hours/night, that's 300 a-h. I think that's more than one typical battery, but maybe two would do? Collectively that will be heavier than a 500w genset, but perhaps still feasible. You could charge it/them with solar panels during the day.

That's all a maybe, just thinking out loud.