  The performance of endoreversible thermal machines operating at finite power
constitutes one of the main challenges of nonequilibrium classical and quantum
thermodynamics, engineering and others. We introduce the idea of adjusting the
interaction time asymmetry in order to optimize the engine performance. We
consider one of the simplest thermal machines, composed of a quantum dot
interacting sequentially with two different reservoirs of heat and particles.
Distinct optimization protocols are analyzed in the framework of stochastic
thermodynamics. Results reveal that asymmetric interaction times play a
fundamental role in enhancing the power output and that maximizations can
provide an increase larger than 25\% the symmetric case. As an extra advantage,
efficiencies at maximum power are slightly greater than the endoreversible
Curzon-Ahlborn efficiency for a broad range of reservoir temperatures.
