# How to find Indicated mean effective pressure?

• falik
In summary, the conversation discusses a 4 stroke, single cylinder engine that operates on a constant volume cycle and develops 7.5 KW brake power at 60 rev/sec with a mechanical efficiency of 80%. The engine has a volumetric compression ratio of 7 and a maximum pressure of 34 bar. The problem is to calculate the Indicated Mean Effective Pressure using the equation Pm = Indicated Power/ LAN. However, the lack of information on the stroke or bore of the engine makes it difficult to solve. The person asking for help suggests adding a section on why questions may not be answered to the forum.
falik

## Homework Statement

A 4 stroke, single cylinder engine working on constant volume cycle, developes 7.5 KW brake power at 60 rev/sec the mechanical efficiency being 80%. The pressure at the beginning of compression is 0.97 bar, the engine has a volumetric compression ratio of 7 and the maximum pressure reached in the cycle is 34 bar. If both compression and expansion is according to the law PV= costant where n=1.38, calculate Indicate Mean Effective Pressure ?

## Homework Equations

indicated power = Pm x Lx A x N

## The Attempt at a Solution

well i have tried different methods, but couldnt solve it, if anyone can help me with that ? ill b really gratefull. thanks.

the thing is that, there is no stroke or bore given in the question and if i use the volumetric compreesion ratio V1/V2 = 7 and put it in

P1V1^1.38 = P2V2^1.38

then i m getting nothing ? obvioulsy to calculate the Effective Pressure ( Pm ), bore or length of stroke should b known,
through the mechnical efficiney i got the indicated power ! but wat to do next ? kindly guide me.

Pm= Indicated Power/ LAN

how to get AxL ?

well i had a very poor experience regarding this forum anyway i do like to leave one suggestion for the admin who r running this forum and that is kindly add one more thing in the topic " Why My Question Is Not Answered ? "

Its not necessary that admin can slove all the prbs, they r also not in full command of the subject.

Byez.

## 1. How is indicated mean effective pressure (IMEP) calculated?

IMEP is calculated by dividing the total work done during a single engine cycle by the total displacement volume of the engine. This is typically measured in units of pressure, such as pounds per square inch (psi) or kilopascals (kPa).

## 2. What factors affect the indicated mean effective pressure?

The indicated mean effective pressure is affected by several factors, including engine speed, air-fuel ratio, combustion chamber design, and engine size. Other factors such as fuel quality, engine condition, and operating conditions can also have an impact on IMEP.

## 3. How can IMEP be used to evaluate engine performance?

IMEP is a useful measure of engine performance as it provides an indication of the average pressure exerted on the piston during the power stroke. This can be used to compare different engine designs, optimize engine tuning, and identify potential issues or inefficiencies in the engine.

## 4. Can IMEP be measured directly?

IMEP cannot be measured directly, but it can be calculated using engine performance data and mathematical equations. Specialized equipment, such as pressure transducers, can also be used to measure the pressure inside the combustion chamber during engine operation.

## 5. How can IMEP be improved?

There are several ways to improve IMEP, including optimizing the air-fuel ratio, increasing the compression ratio, improving combustion efficiency, and reducing frictional losses within the engine. Proper maintenance and tuning of the engine can also help to improve IMEP and overall engine performance.

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