7.1. General informationFor all models of the car use of unleaded gasoline is allowed though unleaded super gasoline is required according to Specifications only for the early B202i and B202 Turbo models (see the Head Toplivnaya and exhaust systems). Features of fuel system allow to minimize toxicity of exhaust gases. All models are equipped with system of ventilation of a case and all late models are equipped with the three-functional catalytic converter. Some models are also equipped with system of recirculation of the fulfilled gases and system of catching of vapors of gasoline.
For some territories (outside Great Britain) there is an established standard of toxicity of exhaust gases which is strictly controlled by the legislation on which on the car the secondary system of admixture of air in an exhaust is installed.
Systems of decrease in toxicity of gases function as follows.
System of ventilation of a caseThe gases and vapors of oil which broke in a case via the double outlet on a cover of a head of cylinders are sucked away in the throttle case, and also through a turbocompressor in the inlet pipeline. On the models equipped with a turbocompressor, a picture a bit different as the turbocompressor is connected directly to the inlet pipeline.
At high depression in the pipeline (in the idling mode, when dumping gas) gases are soaked up from a case in the throttle case. At weak depression in the pipeline (acceleration, the movement with full gas) gases are pushed out from a case under the influence of rather high pressure in a case; at considerable wear of the engine the rising pressure in a case (because of increase in break of gases) leads to the fact that a part of a stream comes back at any condition of the pipeline.
The catalyst with an electronically controlled smeseobrazovatelFor minimization of the pollution getting from the exhaust system to the atmosphere, some models are equipped with the catalytic converter which is switched on in the exhaust system. The system of catalytic transformation is system of the closed type in which the lambda probe, being a part of the exhaust system, provides the electronic actuation device (ECU) of system of injection of fuel / ignition with data on the content of oxygen in exhaust gases. These data allow the electronic actuation device to issue the command for adjustment of mix with the purpose of providing the best conditions for operation of the catalytic converter.
The lambda probe has the built-in heating element fed by the electronic actuation device by means of the relay a lambda probe. The element is intended for a bystry warming up of a tip of the sensor up to the effective working temperature. The tip of the sensor is sensitive to the content in gases of oxygen and gives in the electronic actuation device a signal of tension of various level, depending on the content of oxygen in exhaust gases; if inlet air-fuel mix is too rich, the sensor gives the high level of tension.
Tension falls at mix impoverishment. The most effective combustion of air-fuel mix happens at correctly chosen composition of mix - 14.7 weight parts of air on one part of fuel ("stoichiometric number"). In this point sensitivity of the sensor has the most abrupt characteristic, the electronic actuation device on the basis of change of a signal at the corresponding moment corrects inlet fuel-air mix by change of duration of an impulse of injection of a fuel injector (duration of opening of the gate).
System of recirculation of the fulfilled gasesThe system carries out under certain conditions circulation of a part of exhaust gases back in combustion chambers for the purpose of reduction of toxicity of exhaust gases. It is reached by effective reduction of peak temperatures in combustion chambers by input of inert exhaust gases. Two systems - the mechanical system and electronic system operated by the electronic LH-Jetronic actuation device were installed.
At emergence of malfunction of system of recirculation of the fulfilled gases (EGR) on an instrument guard the alarm lamp of "check engine" (check the engine) lights up, and in the electronic LH-Jetronic actuation device the corresponding code of malfunction is fixed.
System of catching of vapors of gasolineFor minimization of emission in the atmosphere of not burned down gasoline vapors on some models the system of catching of vapors of gasoline (ELCD) is installed. The cover of a jellied mouth of the fuel tank is pressurized, and in the right forward part of the car under the right wing the coal adsorber for collecting the vapors of gasoline accumulating in a tank during the parking of the car is established. Vapors collect until they cannot be removed from an adsorber (under control of the electronic actuation device (ECU) of fuel system via the purge valve). At the same time vapors are removed to the inlet highway and burn down in the engine.
For the correct operation of the cold engine and/or operation of the engine on single turns, and also for protection of the catalytic converter against effect of reenrichment of mix during warming up of the engine, and also in operating time of the engine under loading, the electronic actuation device does not open the valve of control of a purge of an adsorber; then the electromagnet of the valve makes closing or opening of the valve for a conclusion of the collected vapors to the inlet highway.
Damper of a butterfly valveThe damper of a butterfly valve on some models is established on the throttle lever on the throttle case. Its task is prevention of sharp closing of a butterfly valve when braking by the engine, for the purpose of avoidance of emission in the atmosphere of not burned down fuel. At an accelerator pedal otpuskaniye at the engine working with turns from 3000 rpm (compulsory idling), the engine has to dump turns to 875 rpm approximately in 4 seconds.
Automatic stabilization of turns of idling (AIC)On some models the system of automatic stabilization of turns of idling which ensures stable functioning of the engine on single turns, at the cold engine and during its warming up, compensation of additional loadings (for ensuring operation of the compressor of the air conditioning system, the generator or system of hydrostrengthening of a wheel), and management of the mode of compulsory idling is installed.
The AIC valve operates a stream of the air making a detour of a butterfly valve. The valve is run by the electronic actuation device (ECU).
Systems of admixture of air in an exhaustOn some models the system of admixture of air in an exhaust using pressure pulsations in a final collector for an air conclusion from the air cleaner is installed. It gives air to the lower line party of a final collector for the purpose of full oxidation of CO of the attendee in exhaust gases.
The secondary injection system of admixture of air in an exhaust injects air in a final collector before the lambda probe and the catalytic converter reach high working temperatures for CO combustion improvement. The system is activated at start of the engine and during its work depending on temperature of the engine and the moment of the beginning of work a lambda probe.