EXHAUST EMISSION CONTROL SYSTEM

Description 1080B

1.2 8v

LAMBDA SENSORS

The Lambda sensors are the "planar" type and one is fitted straight after the exhaust manifold but before the catalytic converter ("PRE'') whilst the second one is fitted straight after the catalytic converter ("POST'').

The two Lambda sensors inform the engine management control unit of the combustion progress; the pre catalytic converter one has the task of analyzing the stoichiometric ratio whilst the post catalytic converter one checks the operation of the catalytic converter informing the engine management control unit which carries out any fine adjustments to the stoichiometric ratio.

To produce an optimum mixture the quantity of air drawn in by the engine must be equal to the theoretical quantity required to burn all of the fuel injected.

Therefore the Lambda factor (?) is the ratio between the quantity of intake air and the theoretical quantity of air and the ideal value is 1.

Therefore:

• ? = 1 ideal mixture
• ? ( 1 lean mixture
• ? ( 1 rich mixture

A, Rich mixture (not enough air)

B, Lean mixture (too much air)

CATALYTIC CONVERTER

The catalytic converter is used to reduce emissions of the three main pollutants:

• HYDROCARBONS = HC
• NITROGEN OXIDES = NoX
• CARBON MONOXIDE = CO

To sum up, the catalytic converter consists of a metal support on which a substrate is deposited which, in turn, contains chemically active material, which has the function of setting off and facilitating two chemical reactions, oxidation to decrease the CO and HC and reduction to decrease the NoX.

The active elements are usually noble materials and RHODIUM or PALLADIUM is used for the reduction reaction, whilst PLATINUM is used for the oxidation.

In addition, there are other chemical compounds present in the substrate that have the basic function of storing and release the oxygen required for the chemical reactions.

This feature of the catalytic converters is known as oxygen storage.

LAMBDA SENSORS

The Lambda sensors are in contact with exhaust gases and generate an electrical signal with the voltage dependent on the oxygen level in the exhaust gases.

Even if the Lambda sensors are the same, working in different gas conditions, they will send the engine management control unit a different signal; the signal coming from the pre catalytic converter sensor is calculated to correct the mixture strength when it differs from the value ? ( (.

At the same time, the post sensor checks to what extent the catalytic converter is keeping down the harmful substances in the exhaust gases and notifies the control unit whether these gases are more or less pollutant and the control unit uses this parameter to ensure the optimum Lambda value = 1.

With the engine cold, to prevent thermal shocks to the ceramic casing due to the formation of condensation, the engine management control unit heats the pre and post catalytic converter Lambda sensors so that they reach the same temperature as the exhaust gases.

The heater and the measuring cell are built into the "planar" (stratified) ceramic element which favours the rapid heating of the cell thereby allowing the closed loop control extremely quickly after the engine has been started.

1, Connecting element

2, Protective sleeve.

3, Planar sensor element.

4, Ceramic support pipe

5, Sensor seat

6, Ceramic seal

7, Protective pipe

LAMBDA SENSORS

The Lambda sensor works on the principle of an oxygen concentration chamber with solid electrolyte.

The measurement chamber surfaces are coated with microporous layers of noble material.

1, Exhaust gas

2, reference air passage

3, Heater

4, Reference voltage

LAMBDA SENSORS

Electrical Properties:

• Heater power supply. 12V
• Heater resistance. 0.5 - 1 kO

CATALYTIC CONVERTER

The new oxygen storage catalyzer in the substrate contains a material with chemical compounds that have the function of storing and releasing the oxygen required by the chemical reactions.

The oxygen storage takes place in lean mixture conditions, whilst in rich mixture conditions the oxygen required for oxidation is released.

This function is a feature of oxygen storage catalyzers.

The chemical reactions in an old or deteriorated catalyzer take place less efficiently with a consequent increase in pollutant emissions; in a new catalyzer, the oxygen storage decreases correctly and the post catalyzer sensor provides an almost constant output voltage because the catalyzer uses all the oxygen for its chemical reactions.

When the catalyzer ages, the oxygen storage effect gradually decreases and therefore the post catalyzer sensor will see an ever decreasing amount of oxygen giving rise to an ever increasing output voltage but with the same frequency as the post catalyzer sensor.

1.6 16v

CONSTRUCTION specifications

The Lambda sensors are the "planar" type and one is fitted straight after the exhaust manifold but before the catalytic converter ("PRE'') whilst the second one is fitted straight after the catalytic converter ("POST'').

The two Lambda sensors inform the engine management control unit of the combustion progress; the pre catalytic converter one has the task of analyzing the stoichiometric ratio whilst the post catalytic converter one checks the operation of the catalytic converter informing the engine management control unit which carries out any fine adjustments to the stoichiometric ratio.

To produce an optimum mixture the quantity of air drawn in by the engine must be equal to the theoretical quantity required to burn all of the fuel injected.

Therefore the Lambda factor (?) is the ratio between the quantity of intake air and the theoretical quantity of air and the ideal value is 1.

Therefore:

• ? = 1 ideal mixture
• ? > 1 lean mixture
• ? < 1 rich mixture

a, Rich mixture (not enough air)

b, Lean mixture (too much air)

COMPONENTS AND OPERATION

The Lambda sensors are in contact with exhaust gases and generate an electrical signal with the voltage dependent on the oxygen level in the exhaust gases.

Even if the Lambda sensors are the same, working in different gas conditions, they will send the engine management control unit a different signal; the signal coming from the pre catalytic converter sensor is calculated to correct the mixture strength when it differs from the value ? ( 1.

At the same time, the post sensor checks to what extent the catalytic converter is keeping down the harmful substances in the exhaust gases and notifies the control unit whether these gases are more or less pollutant and the control unit uses this parameter to ensure the optimum Lambda value = 1.

With the engine cold, to prevent thermal shocks to the ceramic casing due to the formation of condensation, the engine management control unit heats the pre and post catalytic converter Lambda sensors so that they reach the same temperature as the exhaust gases.

The heater and the measuring cell are built into the "planar" (stratified) ceramic element which favours the rapid heating of the cell thereby allowing the closed loop control extremely quickly after the engine has been started.

1, Connecting element

2, Protective sleeve.

3, Planar sensor element.

4, Ceramic support pipe

5, Sensor seat

6, Ceramic seal

7, Protective pipe

COMPONENTS AND OPERATION

The Lambda sensor works on the principle of an oxygen concentration chamber with solid electrolyte.

The measurement chamber surfaces are coated with microporous layers of noble material.

1, Exhaust gas

2, Reference air passage

3, Heater

4, Reference voltage

COMPONENTS AND OPERATION

Electrical Properties:

• Heater power supply. 12V
• Heater resistance. 0.5 - 1 kO

CONSTRUCTION specifications

The exhaust emission control system includes devices designed to reduce atmospheric levels of harmful emissions:

• exhaust emissions
• vapour/gas emissions from the crankcase

Construction and composition specifications

The catalytic converter is used to reduce emissions of the three main pollutants:

• HYDROCARBONS = HC
• NITROGEN OXIDES = NoX
• CARBON MONOXIDE = CO

To sum up, the catalytic converter consists of a metal support on which a substrate is deposited which, in turn, contains chemically active material, which has the function of setting off and facilitating two chemical reactions, oxidation to decrease the CO and HC and reduction to decrease the NoX.

The active elements are usually noble materials and RHODIUM or PALLADIUM is used for the reduction reaction, whilst PLATINUM is used for the oxidation.

In addition, there are other chemical compounds present in the substrate that have the basic function of storing and release the oxygen required for the chemical reactions.

This feature of the catalytic converters is known as oxygen storage.

OPERATION

The oxygen storage catalyzer in the substrate contains a material with chemical compounds that have the function of storing and releasing the oxygen required by the chemical reactions.

The oxygen storage takes place in lean mixture conditions, whilst in rich mixture conditions the oxygen required for oxidation is released.

This function is a feature of oxygen storage catalyzers.

The chemical reactions in an old or deteriorated catalyzer take place less efficiently with a consequent increase in pollutant emissions; in a new catalyzer, the oxygen storage decreases correctly and the post catalyzer sensor provides an almost constant output voltage because the catalyzer uses all the oxygen for its chemical reactions.

When the catalyzer ages, the oxygen storage effect gradually decreases and therefore the post catalyzer sensor will see an ever decreasing amount of oxygen giving rise to an ever increasing output voltage but with the same frequency as the post catalyzer sensor.

The nobile metals in the catalytic converter suffer chemical attack if lead is present, partly due to the high temperature inside the converter. For this reason, the use of leaded fuel should be be avoided, otherwise the converter will be rapidly and irreversibly put out of service. Never use leaded fuel, not even for a short time in an emergency.

1.2 8v, 1.6 16v

SPECIFICATIONS

The catalytic converter is a post-treatment device for oxidizing the CO, HC and particles transforming them into carbon dioxide (CO2) and water vapour (H20).

The catalytic converter consists of a ceramic, honeycomb structure (1) with cells impregnated with platinum (2) which catalyzes the oxidation reactions.

OPERATION

The exhaust gases passing through the cells heat the catalyzer triggering off the conversion of the pollutants into inert compounds.

The oxidizing chemical reaction of the CO, HC and particles is effective at temperatures of between 200 and 350°C.

In effect, above 350°C the sulphur contained in the diesel fuel starts to oxidize producing sulphur dioxide and sulphur trioxide.

CATALYTIC CONVERTER

The catalytic converter is a post-treatment device for oxidizing the CO, HC and particles transforming them into carbon dioxide (CO2) and water vapour (H20).

The catalytic converter consists of a ceramic, honeycomb structure (1) with cells impregnated with platinum (2) which catalyzes the oxidation reactions.

The exhaust gases passing through the cells heat the catalyzer triggering off the conversion of the pollutants into inert compounds.

The oxidizing chemical reaction of the CO, HC and particles is effective at temperatures of between 200 and 350°C.

In effect, above 350°C the sulphur contained in the diesel fuel starts to oxidize producing sulphur dioxide and sulphur trioxide.

1.6 16v · BIPOWER

CONSTRUCTION SPECIFICATIONS

The Lambda sensors are the "planar" type and one is fitted straight after the exhaust manifold but before the catalytic converter ("PRE'') whilst the second one is fitted straight after the catalytic converter ("POST'').

The two Lambda sensors inform the engine management control unit of the combustion progress; the pre catalytic converter one has the task of analyzing the stoichiometric ratio whilst the post catalytic converter one checks the operation of the catalytic converter informing the engine management control unit which carries out any fine adjustments to the stoichiometric ratio.

To produce an optimum mixture the quantity of air drawn in by the engine must be equal to the theoretical quantity required to burn all of the fuel injected.

Therefore the Lambda factor (?) is the ratio between the quantity of intake air and the theoretical quantity of air and the ideal value is 1.

Therefore:

• ? = 1 ideal mixture
• ? > 1 lean mixture
• ? < 1 rich mixture

a, Rich mixture (not enough air)

b, Lean mixture (too much air)

COMPONENTS AND OPERATION

The Lambda sensors are in contact with exhaust gases and generate an electrical signal with the voltage dependent on the oxygen level in the exhaust gases.

Even if the Lambda sensors are the same, working in different gas conditions, they will send the engine management control unit a different signal; the signal coming from the pre catalytic converter sensor is calculated to correct the mixture strength when it differs from the value ? =1.

At the same time, the post sensor checks to what extent the catalytic converter is keeping down the harmful substances in the exhaust gases and notifies the control unit whether these gases are more or less pollutant and the control unit uses this parameter to ensure the optimum Lambda value = 1.

With the engine cold, to prevent thermal shocks to the ceramic casing due to the formation of condensation, the engine management control unit heats the pre and post catalytic converter Lambda sensors so that they reach the same temperature as the exhaust gases.

The heater and the measuring cell are built into the "planar" (stratified) ceramic element which favours the rapid heating of the cell thereby allowing the closed loop control extremely quickly after the engine has been started.

1, Connecting element

2, Protective sleeve.

3, Planar sensor element.

4, Ceramic support pipe

5, Sensor seat

6, Ceramic seal

7, Protective pipe

COMPONENTS AND OPERATION

The Lambda sensor works on the principle of an oxygen concentration chamber with solid electrolyte.

The measurement chamber surfaces are coated with microporous layers of noble material.

1, Exhaust gas

2, Reference air passage

3, Heater

4, Reference voltage

COMPONENTS AND OPERATION

Electrical Properties:

• Heater power supply. 12V
• Heater resistance. 0.5 - 1 kO

CONSTRUCTION SPECIFICATIONS

The exhaust emission control system includes devices designed to reduce atmospheric levels of harmful emissions:

• exhaust emissions
• vapour/gas emissions from the crankcase

CONSTRUCTION SPECIFICATIONS AND COMPOSITION

The catalytic converter is used to reduce emissions of the three main pollutants:

• HYDROCARBONS = HC
• NITROGEN OXIDES = NoX
• CARBON MONOXIDE = CO

To sum up, the catalytic converter consists of a metal support on which a substrate is deposited which, in turn, contains chemically active material, which has the function of setting off and facilitating two chemical reactions, oxidation to decrease the CO and HC and reduction to decrease the NoX.

The active elements are usually noble materials and RHODIUM or PALLADIUM is used for the reduction reaction, whilst PLATINUM is used for the oxidation.

In addition, there are other chemical compounds present in the substrate that have the basic function of storing and release the oxygen required for the chemical reactions.

This feature of the catalytic converters is known as oxygen storage.

OPERATION

The oxygen storage catalyzer in the substrate contains a material with chemical compounds that have the function of storing and releasing the oxygen required by the chemical reactions.

The oxygen storage takes place in lean mixture conditions, whilst in rich mixture conditions the oxygen required for oxidation is released.

This function is a feature of oxygen storage catalyzers.

The chemical reactions in an old or deteriorated catalyzer take place less efficiently with a consequent increase in pollutant emissions; in a new catalyzer, the oxygen storage decreases correctly and the post catalyzer sensor provides an almost constant output voltage because the catalyzer uses all the oxygen for its chemical reactions.

When the catalyzer ages, the oxygen storage effect gradually decreases and therefore the post catalyzer sensor will see an ever decreasing amount of oxygen giving rise to an ever increasing output voltage but with the same frequency as the post catalyzer sensor.

The nobile metals in the catalytic converter suffer chemical attack if lead is present, partly due to the high temperature inside the converter. For this reason, the use of leaded fuel should be be avoided, otherwise the converter will be rapidly and irreversibly put out of service. Never use leaded fuel, not even for a short time in an emergency.

1.3 JTD 16V, 1.9 JTD 8V

DESCRIPTION OF COMPONENTS

CATALYTIC CONVERTER

Specifications

The catalytic converter is a post-treatment device for oxidizing the CO, HC and particles transforming them into carbon dioxide (CO2) and water vapour (H20).

The catalytic converter consists of a ceramic, honeycomb structure (1) with cells impregnated with platinum (2) which catalyzes the oxidation reactions.

Operation

The exhaust gases passing through the cells heat the catalyzer triggering off the conversion of the pollutants into inert compounds.

The oxidizing chemical reaction of the CO, HC and particles is effective at temperatures of between 200 and 350°C.

In effect, above 350°C the sulphur contained in the diesel fuel starts to oxidize producing sulphur dioxide and sulphur trioxide.

DPF SYSTEM (Diesel Particulate Filter)

This is a mechanical filter that "traps" the carbon particles (particulate) and the engine oil ashes in the exhaust gases in diesel engines.

The action of the DPF makes it possible to keep carbon particle levels down by around 90% in line with Euro 4 and 5 regulations.

The operation of the DPF system is managed by the engine injection control unit by means of suitable strategies. In addition to the actual filter the DPF system comprises an exhaust gas temperature sensor and a differential pressure sensor.

The differential pressure sensor measures the pressure of the exhaust gases upstream and downstream of the filter, by means of special pipes, signalling the gradual accumulation of particulate to the control unit. The particulate accumulation process and the relative increase in the pressure of the exhaust gases inside the filter depends on the engine load, the weight of the vehicle and the engine capacity and power. Therefore the particulate needs to be removed on a regular basis, regenerating the filter following a procedure that makes use of multiple injections to increase the temperature of the exhaust gases (about 600°C) and burn the particulate. The regeneration procedure is controlled by the injection control unit which acts: on the metering of the fuel (up to five injections in the same engine cycle per cylinder) and on the control of the air (E.G.R. and supercharging pressure).

The regeneration phase takes place over a few minutes and does not affect the continuity of the torque supplied by the engine in terms of normal operation.

1. Turbocharger-exhaust manifold assembly

2. Catalytic converter

3. Filter

4. Exhaust gas pressure intake (*)

5. Exhaust gas temperature sensor downstream of the catalyzer

6. Exhaust gas temperature sensor downstream of the filter

7. Differential pressure sensor

8. Injection control unit

(*) There are 2 sensors (upstream and downstream of the filter) on the 1.9 JTD 8V versions; there is only one sensor on the 1.3 JTD 16V version upstream of the filter.

1.4 8v

LAMBDA SENSOR

Specifications

The "planar" type sensors are fitted upstream and downstream of the catalytic converter andinform the injection control unit of the progress of the combustion (stoichiometric ratio).

To produce an optimum mixture the quantity of air drawn in by the engine must be equal to the theoretical quantity required to burn all of the fuel injected.

In this case the Lambda factor ratio between the quantity of intake air and the theoretical quantity of air (required to burn all the fuel injected) is equal to 1.

Therefore:

- Lambda = 1 ideal mixture

- Lambda > 1 lean mixture

- Lambda < 1 rich mixture

a, Rich mixture (not enough air)

b, Lean mixture (too much air)

The Lambda sensors are in contact with exhaust gases and generate an electrical signal with voltage dependent on oxygen level in the gas.

This voltage alters abruptly when mixture composition deviates from Lambda = 1.

The injection control unit manages lambda sensor heating in proportion with exhaust gas temperature.

This avoids thermal shocks to the ceramic case due to contact with condensed water present in exhaust gas when the engine is cold.

The measurement chamber and heater are built into a planar (laminated) ceramic element that offers the benefit of fast chamber heating. This allows closed loop (Lambda = 1) control within 10 seconds of engine start-up.

1. Connecting element

2. Protective sleeve

3. Planar sensor element

4. Ceramic support pipe

5. Sensor seat

6. Ceramic seal

7. Protective pipe

The Lambda sensor works on the principle of an oxygen concentration chamber with solid electrolyte.

The measurement chamber surfaces are coated with microporous layers of noble material.

1. Exhaust gas

2. Reference air passage

3. Heater

ELECTRICAL SPECIFICATIONS:

- Heater power supply: 12 V

- Heater resistance: 0.5 - 1 kOhm.

CATALYTIC CONVERTER

The three-way catalytic converter makes it possible to keep down the levels of the three pollutant gases in the exhaust gases at the same time:

- Unburnt hydrocarbons (HC);

- Carbon monoxide (CO);

- Nitrogen oxides (NOx).

Two types of chemical reaction take place inside the catalytic converter:

- Oxidation of CO and HC to carbon dioxide (CO2) and water (H2O)

- Reduction of NOx to nitrogen (N2).

The converter consists of a structure, a metal gauze suppoart to dampen impacts and vibrations and a stainless steel outer casing that is resistant to high temperatures and atmospheric agents.

The honeycomb structure is made from a ceramic material covered in an extermely thin layer of catalytically active substances, platinum or rhodium, which accelerated the chemical decomposition of the harmful substances contained in the exhaust gases which, when passing through the core cells at temperatures above 300 ° - 350°C, activate the catalyzers setting off the oxidation/reduction reactions.

A perforated steel cone improves the diffusion of the exhausts gases in the ceramic core cells to ensure the optimum efficiency and lifespan of the catalyzer.

1. Ceramic structure

2. Metal support

3. Outer casing

4. Perforated steel cone

The nobile metals in the catalytic converter suffer chemical attack if lead is present, partly due to the high temperature inside the converter. For this reason, the use of leaded fuel should be be avoided, otherwise the converter will be rapidly and irreversibly put out of service. Never use leaded fuel, even for a short time in an emergency.