Opel Astra, Zafira

Since 1998 of release

Repair and car operation

Systems of decrease in toxicity of the fulfilled gases - the general information

Petrol models

For the purpose of decrease in level of issue in atmosphere of the toxic components getting to structure of fulfilled gases of the engine as a result of evaporation and incompleteness of combustion of fuel, and also for maintenance of efficiency of return of the engine and decrease in the expense of the fuel, petrol models considered in the present Management are equipped by variety of special systems which could be united under the general name of control systems of the engine and decrease in toxicity of the fulfilled gases.

To number of the systems concerning management by work of the engine and the control of toxicity of fulfilled gases, it is necessary to carry the following:

• The system of onboard diagnostics (OBD), - see the Head an engine Electric equipment;
• The electronic control system of the engine - see the Head an engine Electric equipment;
• System of operated ventilation картера (PCV);
• System рециркуляции the fulfilled gases (EGR);
• System of catching of fuel evaporations (EVAP);
• The Katalitichesky converter and ljambda-probe (the control of structure of the fulfilled gases).

Functioning of all listed systems, anyhow, directly or indirectly, is connected with management of decrease in toxicity of the fulfilled gases.

In the Sections resulted more low the general descriptions of principles of functioning of each of systems are given, and also procedures of diagnostic checks and regenerative repair (if that is obviously possible) components of the systems which performance lies within qualification of the average mechanic-fan are stated.

Before to come to conclusion about refusal any of systems of decrease in toxicity, attentively check up serviceability of functioning of power supply systems and ignition (Heads of the Power supply system and release and an engine Electric equipment see). Diagnostics of systems of decrease in toxicity some of knots demands use special, difficult in application, the equipment and certain qualification of the executor that is why, it will be reasonable to charge its performance to professional mechanics of a specialised car repair shop.

Told above does not mean that service and repair of components of systems of decrease in toxicity in practice are represented exigeant. Do not forget that one of the most widespread causes of failures is elementary infringement of quality of vacuum or electric connections that is why, first of all always it is necessary to check a condition штуцерных and electric sockets. The owner of the car can make independently and simply enough variety of checks, and also, execute in house conditions set of procedures of routine maintenance of the majority of components of systems, using thus a usual set of the adjusting and metalwork tool.

Try to observe all measures of precautions stipulated in below-mentioned Sections at performance of service of electronic components of considered systems. It is necessary to notice that the illustrative material can correspond not always in accuracy to real placing of components on the car. Such discrepancies are connected with continuously occurring process of updating within the limits of a typical design of each model.

In an impellent compartment of the car the information label of systems of decrease in toxicity of the fulfilled gases (VECI) is fixed. On a label the necessary information on options and checks of under control systems taking into account all updatings made on the concrete car, and also the scheme of a lining of vacuum hoses with identification of various components contains. Before to start service of systems of decrease in toxicity and management of engine work, attentively familiarise with data VECI.

Ventilation system картера (PCV)

System PCV serves for issue decrease in atmosphere of hydrocarbonic connections at the expense of a conclusion from the engine картерных gases. The block purge is carried out by prorace of fresh air arriving from an air cleaner through картер in which it mixes up with the collected evaporations and broken of chambers of combustion by gases and deduced through valve PCV in the inlet pipeline.

Valve PCV, the filter of a purge and the complete set of the vacuum hoses connecting listed devices with the engine concern number of the basic components of system.

For the purpose of maintenance of stability of turns of idling valve PCV blocks a purge stream at deep depression in the inlet pipeline. In case of infringement of serviceability of functioning of the engine (as, for example, at wear process of piston rings) the system makes surplus tap картерных gases through a ventilating tube back in an air cleaner.

The control of structure of the fulfilled gases

For the purpose of issue minimisation in atmosphere of toxic components about structure of system of release of the fulfilled gases it is included каталитический the converter. The control is carried out by a control system of the closed type. The feedback with ECM is organised by means of built in in a reception pipe of system of release of a ljambda-probe.

The Katalitichesky converter is a component of systems of decrease in toxicity of the fulfilled gases, is included in structure of system of release and serves for issue decrease in atmosphere of toxic components. On cars considered in the present Management are used каталитические converters of two types. The usual oxidising converter allows to lower the maintenance in the fulfilled gases of hydrocarbons and монооксида carbon. Three-functional каталитический the converter in addition allows to reduce issue оксидов nitrogen (NО _x).

The ljambda-probe (the oxygen gauge) traces the oxygen maintenance in a stream of the fulfilled gases. At contact of molecules About _{2 with a} sensitive element of a probe the gauge develops a peak signal in a range from 0.1 to 0.9 In, depending on concentration of oxygen. And, to value 0.1 In there corresponds the high maintenance About _{2 (the} impoverished mix), and to value 0.9 In - low (the enriched mix). ECM continuously supervises signals arriving from a ljambda-probe, in case of need giving out commands on updating of structure of an air-fuel mix at the expense of change of duration of opening of injectors of injection. The optimum parity of components of the gas mixture, guaranteeing the minimum expense of fuel at the most effective functioning каталитического the converter, makes 14.7 parts of air on 1 part of fuel, - its module of management and tries to support constantly, being guided by the information arriving from a ljambda-probe. On considered models of cars two ljambda-probes are used; the primary is located in a final collector of the engine, and secondary - more low каталитического the converter. By comparison of level of the maintenance of oxygen on sites of a final path above and more low каталитического converter ECM defines also efficiency of functioning of the last.

It is necessary to notice that the ljambda-probe is capable to develop alarm pressure only being heated-up to normal working temperature (nearby 320°С). While the gauge is in a cold condition, ECM works in a mode of the OPENED CONTOUR.

In case of infringement of serviceability of functioning of a ljambda-probe or its chain ECM passes in emergency operation (a mode of the opened contour), ignoring the information arriving from gauges and supporting structure of an air-fuel mix at some set level providing sufficient efficiency of return of the engine.

Serviceability of functioning of a ljambda-probe depends on performance of set of some certain conditions:

• Electric parametres: Stability of a peak signal of a low voltage developed by the gauge in the big degree depends on quality of contact connections of a chain of a ljambda-probe which should be checked first of all in case of occurrence of problems;
• Giving of external air: the ljambda-probe Design provides free circulation of external air in the gauge. At probe installation always check passableness of air channels;
• Working temperature: ECM starts to react to the information arriving from a ljambda-probe only after the gauge will be heated-up to normal working temperature (nearby 320°С). It is necessary not to lose sight of the given fact at check of serviceability of functioning of a probe;
• Quality of fuel: Serviceable functioning of a ljambda-probe becomes possible only under condition of application for refuelling of car NEETILIROVANNOGO of fuel!

System of catching of fuel evaporations (EVAP)

The system accumulates accumulating in the power supply system during car parking fuel evaporations and provides their conclusion in the inlet pipeline for burning in the course of normal functioning of the engine.

The structure of any system EVAP necessarily includes the special adsorber filled with activated coal which, actually, and collects in itself fuel evaporations. The way of a conclusion of evaporations from an adsorber can vary depending on a design of concrete system. The description resulted more low will allow the reader to understand principles of functioning of system EVAP of any type in details enough.

The cover of a jellied mouth of a fuel tank is equipped by a bilaterial safety valve. In default systems the valve provides tap of fuel evaporations in atmosphere.

Another запорный the valve (valve ORVR) is established near to a fuel tank and provides adjustment of tap of fuel evaporations in a coal adsorber depending on the differences of pressure/depression connected with change of temperature.

On the way to a coal adsorber fuel evaporations are passed through the double-thread valve and on ventilating hoses get to the coal adsorber established in an impellent compartment where accumulate during all time of parking.

At start of the engine till the moment of its warming up to certain temperature запорный the electromagnetic valve of a purge of an adsorber remains closed, supposing opening диафрагменного the valve of a purge at the expense of increase in depth of depression in the inlet pipeline. From an adsorber fuel evaporations through диафрагменный the valve are blown in the inlet pipeline, whence arrive in combustion chambers where are burnt out in the course of normal functioning of the engine.

The fuel tank also is usually equipped by the gauge tracing changes of pressure in a tank as during parking, and on the move the car.

System рециркуляции the fulfilled gases (EGR)

For the purpose of issue decrease in atmosphere of oxides of nitrogen the engine design provides tap of a part of the fulfilled gases in the inlet pipeline through valve EGR. Such подмешивание the fulfilled gases to an air-fuel mix leads to decrease in temperature of its combustion.

The system consists of valve EGR, the gauge of degree of opening of valve EGR, the management module (ECM) and the complete set of auxiliary information gauges. ECM is programmed so that to provide optimum degree of opening of valve EGR for any operating conditions of the engine. The special information gauge constantly traces degree of opening of valve EGR, giving out corresponding signals on the management module. ECM compares the entering information of the gauge to the optimum settlement size defined under the data, arriving from other information gauges and, in case of need, makes demanded updating of volume of the fulfilled gases arriving in the engine.

On models 1.4, 1.6 and 1.8 l are used the electric valve EGR established on the inlet pipeline, or at the left on a head of cylinders. On engines of 2.0 l it is used electromagnetic клапанный knot EGR placed on a head of cylinders.

Diesel models

On diesel models the general control of structure of the fulfilled gases carries out also the engine management module (ECM). The same Main objective, as on petrol models, - reception of peak efficiency of return of the engine at the minimum expenses in a combination to emission minimisation in atmosphere of toxic making products of combustion.

The task in view decision is carried out by three basic systems: ventilation system картера (PCV), system рециркуляции the fulfilled gases (EGR) and каталитический the converter.

System of operated ventilation картера (PCV)

The principle of functioning of system PCV is completely similar described above for petrol engines.

The control of structure of the fulfilled gases

The main element of the monitoring system is каталитический the converter providing additional oxidation монооксида of carbon (WITH), - see above.

System рециркуляции the fulfilled gases (EGR)

The principle of functioning of system EGR is similar described above for petrol engines. Vacuum valve EGR is established in the top part of the inlet pipeline and works on commands ECM which is given out on an electromagnet of management.