Method of treating unburned hydrocarbons emitted by a spark ignition combustion engine running on natural gas as well as a device to apply said method

摘要

Below a certain temperature threshold for the gases circulating in the engine exhaust line, a gas mixture containing ozone is injected into the exhaust line to oxidize the unburned hydrocarbons. Above the threshold, the unburned hydrocarbons are treated using a catalytic converter. The threshold temperature is the semi-conversion temperature for methane. The device to carry out this process includes a catalytic converter (3) and a temperature detector (5) upstream of the converter in the exhaust pipe (9) of the engine. An air inlet line (6) parallel to the exhaust pipe carries an air pump (4) and an air ionization device (2). Means of injection (8) allow the gas mixture from the air ionization device to be introduced into the exhaust pipe. The means (7) of controlling the air pump, the ionization device and the means of injection all operate as a function of the temperature measured by the detector. The means of injection connect to the exhaust pipe upstream or downstream of the catalytic converter. The air ionization device is made of several reactors placed in series in the air inlet line. A gas ionization device is placed in the exhaust pipe with means of controlling it. The means of control for the gas ionization device are independent of the means of controlling the air ionization device.