  We suggest a method of summing the perturbation theory (PT) asymptotic series
related to infrared (IR) renormalons in QCD by using special renormalization
schemes in which the running coupling can be integrated over the region of
small momenta. For the method to work, one should consider higher order PT
corrections to the standard bubble-chain diagrams. High-order corrections allow
one to choose a scheme in which the coupling evolution can smoothly be
extrapolated to small momenta. In such schemes the sum of an (extended)
IR-renormalon asymptotic series is defined as an integral of the running
coupling over the IR region. We give explicit examples of renormalization
schemes in QCD which can be used for summing IR-renormalon asymptotic series
according to our definition.
