Gas collection techniques for determining hydrocarbons (HCs) in automotive exhaust are discussed.
Stability of HCs in a Tedlar bag (3L) is cleared on this study. C7-C12 alkanes storaged in the Tedlar bag were lower than correct value by adsorption on bag surface. HCs storaged in the Tedlar bag were higher than correct value by condensation of water vapor immediately after sampling.
Sampling techniques of vehicle exhaust gases that can be getting reliability must satisfy a number of requirements. It needs to retain the components in exhaust gases for several hours, without photo chemical reactions, and to collected it at a constant speed.
Sampling method, therefore, both with a heated stainless steel canister and with a sampling method with a heated stainless steel syringe were developed to satisfy these requirements.
In the heated stainless steel canister, C7- C12 alkanes were stable for 1 hour and water vapor was stable for 10 minutes at 120 °C, and in the heated stainless steel syringe, these were stable for 3 hours at 120 °C.
The flow rate of exhaust gas collected into the heated stainless steel canister was stable from 15 seconds to end. The flow rate of exhaust gas collected into the heated stainless steel syringe was constant.