13.2. General information
System of decrease in toxicity of exhaust gases
On all models with petrol engines it is possible to apply unleaded gasoline. Control systems of the engine choose the optimum mode for a combination of dynamic characteristics of the car, the minimum consumption of fuel and reduction of harmful substances in exhaust gases.
To reduce pollution of the atmosphere from incompleteness of the burned hydrocarbons and the evaporating gases and to create optimum conditions for operation of the engine, the following systems of decrease in toxicity of exhaust gases are applied:
– the system of ventilation of a case reducing emission of pollutants from the engine lubrication system (is established on all models);
– the catalyst neutralizing harmful substances in exhaust gases (is established on the majority of models);
– the system of catching of vapors of fuel reducing an exit of gaseous hydrocarbons and the fuel tank (is established on all models).
Besides, on some models the system of repeated combustion of exhaust gases (EGR) and system of compulsory forcing of air which reduces amount of not burned down fuel in exhaust gases is installed.
All diesel engines are also equipped with system of ventilation of a case. Also on some models the catalyst and system of repeated combustion of exhaust gases (EGR) is installed.
System of ventilation of a case
To reduce emission of not burned hydrocarbons from a case in the atmosphere, at the tight engine crankcase gases and oil vapors are delayed from a case to the highway of air supply in the engine and burned up by the engine.
Catalytic converter on models from a benzinova ми engines
For reduction of emissions of harmful substances with exhaust gases on the majority of models establish каталитичес a cue the converter. On all models with the catalytic converter the power supply system fuel of the closed type, i.e. on the basis of the signal from the Lambda sensor established in a reception exhaust pipe, the ECU block constantly optimizes composition of fuel-air mix.
For normal work of Lyambda-datchi it has a heater which is run by the ECU block and via the relay the Lambda sensor maintains constant temperature the Lambda sensor. Depending on the content of oxygen in exhaust gases the Lambda sensor induces tension from 0,1 B (high content of oxygen, poor mix) to 0,9 B (low content of oxygen, rich mix). On the basis of these data the control unit of the engine changes time of opening of fuel nozzles and changes a fuel ratio in fuel mix. Stekhiometri a chesky ratio of fuel mix at which there is its full combustion and in exhaust there are no harmful substances, are 14,7 weight parts of air on 1 part of fuel.
Additional air supply in the exhaust system reduces emission of harmful substances and WITH. The air pump put in action from an auxiliary driving belt pumps up air under pressure in a final collector where fresh air mixes up with incompleteness the burned-down fuel particles. Fresh air makes final oxidation of not burned down substances, turning them into carbon dioxide and water vapor.
For reduction of emission of an oxide of nitrogen in the atmosphere together with exhaust gases a part of exhaust gases via the EGR valve comes to an inlet collector and is repeatedly burned.
Catalytic a neytraliza of Torahs of exhaust gases on models with diesel engines
On models with diesel engines install the oxidizing catalyst which neutralizes gaseous hydrocarbons and WITH in exhaust gases in the exhaust system. On some models in the exhaust system the special filter which catches firm particles of hydrocarbons is installed.
On some models the system of repeated burning is installed it is fulfilled ny gases. During the work of this system for reduction of emission of an oxide of nitrogen in the atmosphere together with exhaust gases, a part of exhaust gases via the valve of system of repeated combustion of exhaust gases comes to an inlet collector and is repeatedly burned. The electric air system of repeated combustion of exhaust gases is run by the ECU block.
System of catching of vapors of fuel on models with petrol engines
For an exception of hit of vapors of fuel in the atmosphere the system of catching of vapors of fuel with the canister filled with charcoal is used. Fuel vapors from the fuel tank and the float-operated camera of the carburetor gather in the canister with charcoal located under the left wing. Fuel vapors from a canister with charcoal at the expense of a difference of pressure are delayed in the case of a throttle and burned in engine cylinders. Process of procrastination of vapors of fuel of a canister with charcoal via the valve of cleaning is regulated by a thermal valve which opens the cleaning valve only after warming up of the engine up to the certain temperature. It is necessary to exclude reenrichment of mix during the operation of the cold engine.
Exhaust system
The exhaust system consists of a final collector, a reception exhaust pipe, mufflers and connecting pipes, the catalytic converter and arms and rubber suspension brackets.
The turbocharger established on model with diesel engines is cooled with oil and has the adjusting valve of pressure. At failure of the adjusting valve the valve of protection of the engine against an overload works and via the executive mechanism reduces fuel supply by the fuel pump of high pressure to the level of the diesel engine without turbo-supercharging.