  We extend the translationally invariant quantum East model to an
inhomogeneous chain with East/West heterojunction structure. In analogy to the
quantum diffusion of substantial particles, we observe a cyclic entanglement
entropy spreading in the heterojunction during time evolution, which can be
regarded as continuous cycles in a quantum heat engine. In order to figure out
the possibility of manipulating the entanglement entropy as a quantum resource,
the entropy growth is shown to be determined by the initial occupation and the
site-dependent chemical potential, and the former is equivalent to an effective
temperature. Through fine adjustment of these parameters, we discover the
entanglement flow is simply superposed with those from two sources of the
chain. An intriguing relation between our model and the traditional heat
engines is subsequently established.
