Flow chart
Air circulation (as per arrows)
- A - outside air intake
- B - exhaust gas + air
- C - exhaust gas
- "a": short inlet duct (helical shape)
- "b": long inlet duct (tangential)
| reference | designation | part number in the electrical diagrams | remarks |
|---|---|---|---|
| 1 | throttle housing control electrovalve (EGR) | 1263 | - |
| 2 | "Swirl" control electrovalve | 1264 | - |
| 3 | "Swirl" control diaphragm | -- | vacuum-controlled |
| 4 | recycling regulation electrovalve (EGR) | 1253 | - |
| 5 | vacuum pump | -- | - |
| 6 | vacuum reservoir | -- | - |
| 7 | exhaust gas recycling valve (EGR) | -- | vacuum-controlled |
| 8 | turbocharging pressure regulation solenoid valve | 1233 | - |
| 9 | exhaust gas manifold | -- | - |
| 10 | inlet air heater throttle control electrovalve | 1285 | - |
| 11 | finned diffuser piston control pneumatic capsule | -- | vacuum-controlled |
| 12 | finned diffuser piston | -- | - |
| 13 | particle filter + catalytic converter | -- | - |
| 14 | exhaust turbine | -- | - |
| 15 | variable geometry turbocharger | -- | - |
| 16 | air inlet turbine | -- | - |
| 17 | air flow meter + air temperature sensor | 1310 | - |
| 18 | air cleaner | -- | - |
| 19 | air/air heat exchanger | -- | - |
| 20 | water-to-air heat exchanger + (inlet air heating) | -- | - |
| 21 | inlet manifold pressure sensor | 1312 | - |
| 22 | inlet air heater throttle | -- | vacuum-controlled |
| 23 | "Swirl" control throttle | -- | - |
| 24 | air inlet manifold | -- | - |
| 25 | exhaust gas/water exchanger | -- | - |
| 26 | throttle butterfly housing (EGR) | -- | vacuum-controlled |
| 27 | injection ECU | 1320 | - |
| 28 | atmospheric pressure sensor (integrated in the injection ECU) | 1320 | - |
NoteEGR: exhaust gas recycling device
Turbocharging pressure regulation solenoid valve: white/grey referenced hose opposite the white spot on the electrovalve
"Swirl" control electrovalve: unreferenced hose
Recycling regulation electrovalve (EGR): hose with white/white reference opposite the white spot on the electrovalve
Throttle housing control electrovalve (EGR): pipe with white/black reference opposite the white spot on the electrovalve
Inlet air heater throttle control electrovalve: white/brown referenced pipe opposite the white point on the electrovalve
Inlet air heater throttle: brown capsule - brown referenced hose
Throttle butterfly housing (EGR): black capsule - black referenced pipe
Components common with the document: "Operating Principle - HDI direct injection system (High Pressure Diesel Direct Injection)"
Components common with the document
- Air cleaner
- (1320) atmospheric pressure sensor
- Air/air heat exchanger
- Inlet manifold pressure sensor (1312)
- Vacuum pump
- Turbocharging pressure regulation solenoid valve (1233)
Special parts
Features of the DW12 TED4 engine
- Vacuum reservoir
- Variable geometry turbocharger
- Variable "Swirl"
- "Swirl" control electrovalve (1264)
Vacuum reservoir
Role
The vacuum reserve allows sufficient braking assistance to be maintained if the following components are controlled simultaneously
- "Swirl" control throttle
- Inlet air heater throttle
- Finned diffuser piston control pneumatic capsule
Description
"c": pressure drop inlet for the vacuum pump
"d": output: "Swirl" control throttle
"e": output: finned diffuser piston control pneumatic capsule
Capacity = 0,5 litre
Location
The vacuum reserve is located in the engine compartment, near to the brake servo (according to vehicle)
NoteThe vacuum circuit contains 3 nozzles of 0,55 mm
Variable geometry turbocharger
Role
The turbocharger allows the engine to be turbocharged with air
The variable geometry turbocharger is used
- To increase the speed of the exhaust gases which strike the turbine at low engine speeds
- To reduce the speed of the exhaust gases which strike the turbine at high engine speeds
- To adapt the turbine to a variation in exhaust gas flow
Description
(11) finned diffuser piston control pneumatic capsule: vacuum-controlled
(12) finned diffuser piston
(14) exhaust turbine
(16) air inlet turbine
(29) thermal housing
"f": gas from the exhaust manifold
"g": to the inlet manifold
The turbocharger consists of two separate chambers
The turbocharger consists of the following components
- A chamber connected to the engine exhaust function
- A chamber connected to the inlet function
- A turbine and a compressor, connected by a shaft
The turbine, activated by the exhaust gas, drives the compressor which compresses the inlet air
The translation of the piston (12) allows the inlet cross section of the exhaust turbine to be varied in order to alter the speed of the exhaust gases
The regulation electrovalve controls the turbocharging pressure regulator piston (12)
Regulation of the boost pressure is progressive and is controlled by mapping (injection ECU)
NoteTurbocharger lubrication: the very high speeds of the moving parts and temperatures demand a careful lubrication
The pressurised oil required for this function is taken from the engine oil circuit
WarningBefore stopping the engine, it is essential to allow the engine to return to idle. failure to observe this condition may cause the destruction of the turbocharger (lack of lubrication)
Operation at low engine speed
The gas flow passing through the exhaust turbine (14) is low
To increase the turbocharging pressure, a maximum amount of energy must be converted in the turbine
The exhaust gases must be made to pass through a small cross section: the finned diffuser piston (12) is closed
WarningThe finned diffuser piston is closed when it is not controlled pneumatically
Operation at high engine speed
Boost pressure regulation: the energy of the exhaust gases is controlled by adjusting the speed at which the gases enter the exhaust turbine by altering the position of the finned diffuser piston
Contrary to a fixed geometry turbocharger, all of the exhaust gas flow passes through the exhaust turbine (no energy lost)
Variable "Swirl"
"a": short inlet duct (helical shape)
"b": long inlet duct (tangential)
Using the short inlet duct allows maximum swirl to be obtained ("Swirl" movement)
Air is let into the inlet ducts by opening the "Swirl" control throttles (used for high engine speeds)
Using 2 inlet ducts allows maximum filling (reduced swirl)
Advantages of the variable "Swirl"
- Optimisation of combustion (air/fuel mixture)
- Better performance/pollutant emissions compromise
The variable "Swirl" gives a reduction in carbon particles
"Swirl" control electrovalve (1264)
Role
The "Swirl" control electrovalve controls the "Swirl" control diaphragm
Description
The control electrovalve connects the vacuum pump and the "Swirl" control diaphragm
"h": vacuum inlet of the vacuum reserve
"j": atmospheric pressure inlet
"k": electrical connector
"l": "user" outlet
The electrovalve is controlled with an OCR (Opening Cyclic Ratio) and using a cartographic map (injection ECU)
The electrovalve is subject to the following elements
- Atmospheric pressure
- Vacuum supplied by the vacuum pump
The pressure supplied by the electrovalve is included between the atmospheric pressure and the vacuum pump vacuum
WarningThe "Swirl" control throttle is closed when it is not controlled pneumatically
Conditions allowing the throttle to open
- Engine speed above 2100 rpm (at 80°C) (2500 rpm at 0°C)
- Fuel flow injected greater than 40 mg/stroke
Electrical special features
Control: injection ECU (earth)
Full supply (maximum OCR) = maximum vacuum
No supply (minimum OCR) = no vacuum (atmospheric pressure)
Resistance at 25 °C = 28 ohms
Location
The "Swirl" control electrovalve is located on the coolant outlet housing
Special feature: inlet manifold pressure sensor (1312)
The inlet manifold pressure sensor is located on the air/air heat exchanger outlet