Question

Where is the variable compression ratio used?

(a) SI engine

(b) CI engine

(c) Wankel engine

(d) HCCI engine

I have been asked this question by my school principal while I was bunking the class.

The doubt is from Nonconventional Engines in section Nonconventional Engines, Conventional Energy Sources & Cooling System of Automobile Engineering

Answer 1

Right option is (a) SI engine

To elaborate: Variable compression is used in SI engines. There are several methods for changing both the geometric and effective compression ratio.