Engine spirituality is "pressure" that exerts by fuel-air combustion.If pressure is inside engine-system,it is work.If pressure is outside,it is gravity. So any engineer must know well about pressure in thermodynamics and gravity in hydraulics-fluid mechanics.

Anybody who wish to know about "ENGINE" which gives power(truth) must note that even though engine works on solid,liquid and gaseous states,engine need be controlled by spiritual(law)(mind) in system.