Rate of heat release

Question 1

What is BMEP

Answer 1

Average effective
pressure of all stroke cycles. (whether they are Two or Four
Cycles).

Question 2

IMEP

Answer 2

Same as BMEP, but does not take in to account mechanical losses

Question 3

What is dynamic cylinder pressure?

Answer 3

Its the pressure at any point in the cylinder.Measured cylinder pressure is the most reliable information about the dynamic processes inside the engine cylinder
* Dynamic pressure is sampled as discrete points throughout one or more cycles, for CI, acquired every 0.25 CAD

Question 4

How to you extract HRR(heat release rate)

Answer 4

See fig 10

Question 5

What is the diffrence between pre-mixed combustion and diffution combustion

Answer 5

In pre-mixed there is a combustion taking place before reaching TDC, while in diffusion we se a broad heat releas at about TDC for diesel engines

Question 6

What is ROHR and its limitations

Answer 6

Calculation on HRR based on motors, so x-axis is CAD not time.
- The pressure sensor in the engine doesn’t tell you the real pressure — it tells you how much the pressure has changed.
- Small differences in cylinder volume, how much air is compressed and compression volume(how mucj air is left on the top all effect how correct the pressure is measured.)