Class 2 (2nd Engineer) MEKM 📅 Nov 2023

Exam Question

With reference to Modern Diesel Engine describe the features of High-pressure Miller cycle and discuss the following.

(a) Reduction in Air Temperature due to Miller Cycle (4)

(b) Recovery of Pressure in the Combustion chamber during the Miller cycle. (4)

(d) The impact on various parameters during low load operation using Miller Cycle. (4)

Reference Answer

The Miller cycle involves early or late intake valve closure to reduce the compression temperature by allowing the air to expand or decrease the net compression ratio. This results in reduced NOx emissions due to lower combustion temperatures. The reduced charge air is compensated by using a high-pressure supercharger or turbocharger to maintain the desired air supply for combustion.
(a) Reduction in air temperature due to the Miller cycle:
The Miller cycle reduces air temperature during compression in the following ways:
Early Intake Valve Closing: Closing the intake valve before the piston reaches Bottom Dead Center (BDC) allows the air to expand as the piston continues downward. This expansion cools the air, lowering the compression temperature.

Full answer on MeoMock — surveyor-grade reference answers for 7,000+ written exam questions.

View plans Browse library

← Browse more questions

Prepare on Android — MeoMock on Google Play