  We analyze the performance of a quantum Otto cycle, employing time-dependent
harmonic oscillator as the working fluid undergoing sudden expansion and
compression strokes during the adiabatic stages, coupled to a squeezed
reservoir. First, we show that the maximum efficiency that our engine can
achieve is 1/2 only, which is in contrast with the earlier studies claiming
unit efficiency under the effect of squeezed reservoir. Then, we obtain
analytic expressions for the upper bound on the efficiency as well as on the
coefficient of performance of the Otto cycle. The obtained bounds are
independent of the parameters of the system and depends on the reservoir
parameters only. Additionally, with hot squeezed thermal bath, we obtain
analytic expression for the efficiency at maximum work which satisfies the
derived upper bound. Further, in the presence of squeezing in the cold
reservoir, we specify an operational regime for the Otto refrigerator otherwise
forbidden in the standard case.
