Question

Which system reduces the pumping losses due to conventional throttle?

(a) Profile switching system

(b) Phase changing system

(c) Variable event-timing system

(d) Variable lift system

This question was addressed to me in an online interview.

I'm obligated to ask this question of Variable Valve Timing topic in chapter Valve Timing Technologies of Automotive Engine Design

Answer 1

Correct option is (d) Variable lift system

Easy explanation: Variable lift system has the main advantage of reducing the pumping losses due to conventional throttle. Variable event-timing system can change both the phase and duration of the valve events.