Combustion engine and method for applying a heat-insulating layer

摘要

This invention provides a porous thermal barrier layer for protecting parts of an internal-combustion engine having parts which are acted upon by combustion, and particularly by heat, and to a process for applying such a thermal barrier layer to these parts. The thermal barrier layer, which is formed of grains and/or fibers connected with one another on the exterior side, and is produced at least partially from a heat-resistant, temperature-shock-stable and abrasion-proof barrier material, has a heat penetration number defined by the following formula b= 2ROOT p.C. lambda with b: the heat penetration number of the thermal barrier layerin [J.(Kcm2 2ROOT s)-1], p: the density of the thermal barrier layer in [g/cm3], lambda : the thermal conductivity of the barrier material in [W/cmK], and C: the specific heat of the barrier material in [J/gK]which heat penetration number is smaller than 0.25 [J.(Kcm2 2ROOT s)-1], particularly smaller than 0.1 [J.(Kcm2 2ROOT s)-]. Furthermore, grains and/or fibers which are hollow are used during the application of the thermal barrier layer, so that the total porosity of the thermal barrier layer 1 is higher than 20%.