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True power comes from torque measured in "Lb/Ft @ a given engine R.P.M.". Horsepower was formulated by an early car salesman who wanted to show the farmers that his product was as reliable as their horses(he also invented the light-bulb...James Watts:) You find the HP can be measured by this " HP=Torque x RPM (divided by) 5252. There are infinite number of variables so that is in its most basic Breakdown.
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Indicated power is the theoretical maximum power output of the engine. The indicated power is the total power available from the expanding gas in the cylinders negating any friction, heat loss or entropy within the system..
To calculate the indicated power it is necessary to make a P/V graph called an indicator diagram of the engines cycle. Using the indicator diagram we have to calculate the Area under the graph (Ad), the Scale Pressure (Sp), the base length of the diagram (Y)
Using this the MEP or mean effective pressure can be calculated using the formula:
(Ad/Y) x Sp = MEP = p
The average force on a piston during each cycle F = MEP x APISTON (engine bore or piston area)= PA
From F = P X A
Work W = F X L (force x distance moved)
Thus: PAL where L is the stroke length of the piston
N is the number of cycles per second (divide your brake Rev/s by 2 for a four stroke engine as two full revolutions = 1 cycle)
giving the equation:
IP=PLAN
Indicated power is measured in kilo-Watts (kW) and is used by engineers to determine the maximum power available from combustion and to determine the engines efficiency.
It is also necessary to know the amount of fuel consumed per second and Calorific or heating value of that fuel so we can calculate the Fuel Power and thus the efficiency of the engine..
The Fuel Power (FP ) is simply the mass of fuel burned per second in kg/s (Mf) x the Calorific Value of that fuel in kJ/kg (CV)
The brake power (BP) is given by 2 π N T
where N is the shaft rev/s and T is the Torque (Net Brake Load x radius of Torque arm)
Indicated Thermal efficiency (NIth) = IP / FP
Brake Thermal Efficiency (NBth) = BP / FP
Mechanical Efficiency (NMech) = BP / IP
With the indicator graph and the formulae above, the engines; Indicated Power (IP), Brake Power (BP), Fuel Power, Torque, Mean Effective Pressure (MEP), Indicated Thermal Efficiency (NIth), Brake Thermal Efficiency (NBth) and Mechanical Efficiency (NMech) can be calculated.
The air-fuel ratio is also very important when designing an engine as to lean or rich a mixture will result in poor performance and/or damage to the engine..
The air-fuel ratio is simply the ratio between the mass of air per second and the mass of fuel per second in equation form, Air-Fuel Ratio = Ma / Mf
The fuel power is calculated on the assumption that all combustible products meet with oxygen during the combustion process.. This is not the case normally and uncombusted fuel will normally remain after the cycle. To help improve the combustion process and thus the IP of the engine devices such as superchargers, intercoolers and turbochargers are used to either compress the air at intake or cool it to increase the volume available..
What else can I help you with?
What is the indicated power formula for four stroke petrol engines?
Work=Power x Time
Why do most very large engines operate on two stroke cycle?
very large is the keyword here. for a very large engines that runs large machines, we need high power engines. two-strike cycle engines produce more power than 4-stroke cycle engines. that's why they are used. as they produce more pollution than 4-strokes, they must be limited to small spaced engines machines or large machines that required very high power.
How does petrol fuel ignite in the engine?
The compressed petrol gas fuel is ignited by a spark plug thus causing the engines' power stroke.
What are advantages of two stroke engines over four stroke engines?
There are a couple, less parts for one therefore lighter. Also, 2 stroke engines fire every time the piston comes to the top. Which means every stroke is a power stroke. 4 stroke engines fire every other time.
Which supplies more power a 4 stroke engine or 2 stroke engine?
2-stroke engines produce much more power than 4-stroke.
How do 2 stroke engines provide more power than a 4 stroke?
In a 2 stroke, every second stroke of the engine is a power stroke. In a 4 stroke, every 4th stroke of the engine is a power stroke. Knowing this, a 2 stroke has double the power as a 4, in the same cc
What is the main purpose of 4-stroke engines?
To provide power.
Why do most very small engines operate on a two-stroke cycle?
two-stroke engines can produce more power than four-stroke engines that have the same size. they can occupy small spaces and produce the desired power. they are on the other hand produce more pollution than 4-stroke engines. that's why they are limited or suitable for small engine spaced machines
Why water is not used as a petrol?
Since water doesn't burn like petrol, it's far less useful to power engines with.
What amount of power required to make the 2 stroke petrol engine to 4 stroke diesel engine?
you cant turn a 2 stroke into a four stroke. and i don't think you can run diesel in a 2 stroke
Why you prefer four stroke engine over two stroke engine?
Four stroke engines are quieter than two strokes, but have less power.
What happens to the speed using 2 stroke compare to 4 stroke?
two stroke engines have a power stroke every second revolution of the crank shaft. four strokes have a power stroke every fourth revolution of the crank shaft. that is why a 125cc two stroke has about the same power as a 250cc four stroke.
