Expansion velocities ( V _ { \mathrm { exp } } ) of different ions and line widths at the base of the lines are measured and analyzed for 24 PNe with [ WC ] -type nuclei ( WRPNe ) , 9 PNe ionized by WELS ( WLPNe ) and 14 ordinary PNe .
A comparative study of the kinematical behavior of the sample clearly demonstrates that WRPNe have in average 40-45 % larger V _ { \mathrm { exp } } , and possibly more turbulence than WLPNe and ordinary PNe .
WLPNe have velocity fields very much alike the ones of ordinary PNe , rather than the ones of WRPNe .
All the samples ( WRPNe , WLPNe and ordinary PNe ) show expansion velocities increasing with age indicators , for example < V _ { \mathrm { exp } } > is larger for low-density nebulae and also it is larger for nebulae around high-temperature stars .
This age effect is much stronger for evolved WRPNe , suggesting that the [ WC ] winds have been accelerating the nebulae for a long time , while for non-WRPNe the acceleration seems to stop at some point when the star reaches a temperature of about 90 000-100 000 K. Non-WR nebulae reach a maximum V _ { \mathrm { exp } } \leq 30 km s ^ { -1 } while evolved WRPNe reach maximum V _ { \mathrm { exp } } of about 40 km s ^ { -1 } .
For all kind of objects ( WRPNe and non-WRPNe ) it is found that in average V _ { \mathrm { exp } } ( N ^ { + } ) is slightly larger than V _ { \mathrm { exp } } ( O ^ { + + } ) , indicating that the nebulae present acceleration of the external shells .