Skoda Felicia

since 1994 release

Repair and operation of the car



Skoda Felicia
+ Cars of the Skoda Felicia brand
+ Maintenance instruction
+ Routine maintenance
+ Repair of the engine
+ Cooling systems, heating
- Power supply system
   + Power supply system of the carburetor engine of 1.3 l
   + System of the central injection (SPFI) of the petrol engine
   + System of the distributed injection (MPFI) of the petrol engine
   + Power supply system of the diesel engine
   - Systems of decrease in toxicity and production of the fulfilled gases
      System of catching of fuel evaporations - the general information and replacement of components
      System of ventilation of a case - the general information
      Removal and installation of the l-probe
      System of recirculation of the fulfilled gases (EGR) - the general information and replacement of components
      Removal and installation of a final collector
      System of release - the general information and replacement of components
      The catalytic converter - the general information and precautionary measures
+ Engine electric equipment
+ Coupling
+ Transmission
+ Power shafts
+ Brake system
+ Suspension bracket and steering
+ Body and finishing of salon
+ Onboard electric equipment





Systems of decrease in toxicity and production of the fulfilled gases

System of catching of fuel evaporations - the general information and replacement of components

Systems of decrease in toxicity of the fulfilled gases

For gas station of all petrol models only unleaded fuel has to be used. The control system of the engine exercises the general control of functioning of the power unit, providing optimum ratios between the power developed by the engine, controllability of the car and composition of the fulfilled gases. In addition the car is equipped a row of the systems providing decrease in toxicity of the fulfilled gases. All petrol engines are standardly equipped with system of ventilation of a case and the catalytic converter. Due to functioning of these systems the general level of issue in the atmosphere of toxic products of combustion of fuel and crankcase gases decreases. Besides the mentioned systems, petrol models are equipped also with system of catching of fuel evaporations.

The system of ventilation of a case is included also in a basic equipment of all cars of models equipped with the diesel engine. In addition diesel models are equipped with the two-functional catalytic converter and system of recirculation of the fulfilled gases (EGR), the issues allowing to reduce the general level of toxicity.

System of ventilation of a case

For decrease in issue in the atmosphere of the crankcase gases containing not burned down hydrocarbonic connections, the block of the engine it is executed hermetically, and accumulating in it the gases and oil evaporations breaking from combustion chambers are removed from a case and via the air cleaner come to combustion chambers where are burned out in the course of normal functioning of the engine.

As a result of deep depression in the inlet pipeline (the movement on single turns or braking by the engine) crankcase gases are extended from the engine by drift. At decrease in depth of depression (acceleration, the movement) a conclusion of gases and evaporations happens to completely open butterfly valve due to relative increase in intra crankcase pressure. As a result of wear of components of piston groups and cylinders of the engine intra crankcase pressure increases due to more intensive break of gases from combustion chambers that leads to the compelled return of a part of the removed stream at any depression in the inlet pipeline.

Control system of composition of the fulfilled gases (petrol models)

For the purpose of minimization of level of toxicity of the fulfilled gases of the engine released into the atmosphere of release of all petrol models is a part of the system the catalytic converter. The oxygen sensor (l-probe) installed to the highway of system of release closes a power supply system feedback contour, informing ECU of a control system of the engine on the level of contents O 2 in the fulfilled gases. On the basis of the analysis of the arriving data of ECU carries out the corresponding correction of composition of air-fuel mix, optimizing thereby process of its combustion.

In the oxygen sensor the heating element which functioning via the special relay ECU operates is built in. A problem of an element is acceleration of warming up of the l-probe up to the optimum working temperature. The working tip of the sensor is sensitive to contents in surrounding space of oxygen. As a result, depending on the level of an oksidation of the fulfilled gases, the sensor gives a signal of the corresponding amplitude on ECU. The minimum toxicity of products of combustion of air-fuel mix is reached at absolutely certain weight ratio of its components, namely: 14.7 parts of air have to fall on 1 weight part of fuel. This ratio is called stoichiometric number. Change of amplitude of an output signal of the sensor near this point happens big steps that allows ECU to use the arriving signals as basic at calculation of the required composition of gas mixture. Correction of composition of mix is carried out due to change of duration of opening of injectors of injection of fuel. The description of procedures of removal and installation of the l-probe is provided in the Section Removal and installation of the l-probe.

Control system of composition of the fulfilled gases (diesel models)

The two-functional catalytic converter is installed in system of production of the fulfilled gases of all diesel models. The converter allows to prevent issue in the atmosphere of the most part of gaseous hydrocarbonic connections, monoxide of carbon (SO) and firm microparticles.

In addition, diesel models are equipped with system of recirculation of the fulfilled gases (EGR). The system allows to reduce the level of emission of the toxic oxides of nitrogen which are formed at combustion of air-fuel mix for periodic the account of return of a part of the fulfilled gases to the inlet pipeline. Return of the fulfilled gases is made via the plunger EGR valve under certain conditions of functioning of the engine. Control of functioning of the EGR system provides an electronic control unit with the diesel.

System of catching of fuel evaporations (petrol models)

For the purpose of minimization of issue in the atmosphere of not burned down hydrocarbonic connections all petrol models are equipped with system of catching of fuel evaporations. The jellied mouth of the fuel tank is closed by a tight cover. On a mudguard of an arch of the left wheel the coal adsorber in which all fuel evaporations accumulating during the parking of the car in a tank are taken away is established. The evaporating fuel accumulates in an adsorber and after start of the engine are brought out of it via the plunger valve of a purge to the inlet highway where it is burned in the course of normal functioning of the car. For the purpose of protection of the catalytic converter against consequences of reenrichment of mix in the course of warming up of the engine or in its operating time on single turns, ECU does not allow opening of the valve of management of an adsorber purge to a final warming up of the unit. At increase in load of the engine the electromagnetic valve begins to function in the pulse mode, carrying out a consecutive conclusion of contents of an adsorber to the inlet highway of the engine.

System of release


The system of production of the fulfilled gases consists of a final collector, a reception pipe, the catalytic converter, two box-shaped mufflers, a set of basic arms and tubular connecting sections. On diesel models and petrol models of 1.6 l the catalytic converter is switched on in structure of section of a reception pipe of system of release whereas on models of 1.3 l the reception pipe and the converter are installed separately from each other.