9-13-nejjtralizaciya-otrabotavshikh-gazov.html

9.13. Neutralisation of the fulfilled gases

Example Duratec-HR: two ljambda-gauges in carburettor engines

By chemical way does to 90 % of components of the fulfilled gas harmless: the three-running catalyst

1 from 2 WITH О₂ it turns out СО₂; from 2 С₂Н₆ 7 О₂ became 4 СО₂ 6 Н₂О; from 2 NO 2 CO it turns out N₂ CO₂.

Basically fuel consists of such components, as carbon and hydrogen. At combustion in the engine carbon incorporates to oxygen from air, forming carbon dioxide (СО₂), and hydrogen () with the same oxygen (О₂) creates water (Н₂О). From one litre of fuel there are approximately 0,9 litres of water. It leaves in the form of "invisible" water steam from an exhaust system. However in the winter at cold start-up it is possible to observe often white exhaust clouds – an indirect sign of the condensed water.

Mondeo with the regulating catalyst – a diesel engine with the oxidation catalyst – all Mondeo with system рециркуляции ОГ

All Mondeo with petrol engines go today with one regulating catalyst, including and system рециркуляции the fulfilled gases. On the contrary, diesel variants have at themselves onboard one catalyst of oxidation and system рециркуляции the fulfilled gases. The regulating catalyst reduces a share окиси carbon approximately on 85 %, hydrocarbon on 80 and nitrogen oxides on almost 70 %. The oxidation catalyst leaves alone nitrogen oxides (the system thinks of it рециркуляции). The designation "adjustable" specifies that issue of the fulfilled gas, not that as with the oxidation catalyst, during operation is actively measured and in a zone of the minimum ordered by norms is corrected. With growth of the passed way (run) each catalyst, however, loses "influence".

Measures the oxygen maintenance in the fulfilled gas – the ljambda-gauge

To reduce reaction time of "the poisonous salted pork fat», in Mondeo it is direct in a collector of the fulfilled gases and behind the catalyst the oxygen gauge is built in. He continuously analyzes the residual maintenance of oxygen in the fulfilled gas. It sends "data" to the electronic block of management: depending on current measurements the onboard computer establishes structure топливовоздушной a gas mixture (poor, rich). It is carried out in quickly replaced sequence. Surplus of air for hydrocarbon combustion, a lack of air for decrease in oxides of nitrogen. "The adjustable" fulfilled gases pass the catalyst which – as it is already told above – will transform them to dioxide of carbon, water steam and nitrogen.

Working temperatures of the catalyst

That the catalyst and the ljambda-gauge functioned, it is necessary to reach their working temperatures (the catalyst: nearby 300 °С). This work carry out the hot fulfilled gas within 25–80 seconds. However these react to too strong heating both elements very sensitively. For example, when not burnt down rests of a gas mixture ignite in the hot catalyst (fault in ignition), temperatures inside can raise to dangerous values. The constancy of temperature around 1200 °С can prematurely make old the catalyst, at temperatures from above 1400 °С the ceramic case расплавляется and the ljambda-gauge thus too heats up. The melted off catalyst can be "exposed" with the help of "good ears» on hissing final noise is it is caused raised противодавлением the fulfilled gas – and sharp losses of capacity. At once be engaged in finding-out of the reasons, differently and the new catalyst under yours Mondeo will have a short life, and final valves in a head of the block of cylinders will burn down for very short time.
Pay attention to faults in ignition: especially at switchings from high transfers or congresses on mountain roads to a mode of compulsory idling – if from an exhaust system sounds are distributed, thoroughly get to the bottom of the reason of this phenomenon.