  We study a quantum Otto cycle that uses a 2-qubit working substance whose
Hamiltonian does not commute with itself at different times during unitary
strokes. We investigate how the cycle responds to the loss of quantum
adiabaticity when these strokes are operated with a finite duration. We find
that qualitative features such as the possibility of counter-rotating cycles
operating as heat engines, or a cycle efficiency that can increase with a
decrease in the temperature difference between the baths, are resilient even to
highly nonadiabatic strokes. However, cycle efficiency rapidly decreases,
although it can still remain above the standard Otto value for small degrees of
quantum nonadiabaticity.
