Motivated by the renewed interest in studying the pion production on n
uclei with protons at few GeV incident energies, we investigate the pi
on production in proton-proton collisions over an energy range of 300
MeV to 2 GeV. Starting from a realistic one-boson-exchange model with
parameters fitted to the amplitudes of the elastic nucleon-nucleon sca
ttering, we perform fully covariant calculations for the total, double
and triple differential cross sections of the p(p, n pi(+))p and p(p,
p pi(0))p reactions. The calculations incorporate the exchange of pi,
rho, omega, and sigma mesons and treat nucleon and delta isobar as in
termediate states. We obtain a reasonably good agreement with the expe
rimental data in the entire range of beam energies, The form of the co
variant delta propagator, the cut-off parameter for the pi NN and pi N
Delta vertex form factors and the energy dependence of the delta isob
ar decay width is investigated.