Citroen Xantia

Since 1993 of release

Repair and car operation

Systems of injection of fuel - the general information

In systems of injection of fuel the electronic block of management (ECU) self-adjusted type is used. In the course of functioning ECU traces and keeps in memory of the installation, allowing to receive the maximum return from the engine. At a battery detachment all introduced installations are erased and ECU reverts to the original state with the base parametres entered into the block of memory on manufacturer. In view of told at primary start after connection of the battery the engine during some time can work astably. Process of exit ECU in an optimum performance mode occupies usually коло 15 minutes and is better passes in process of a trial trip during which it is necessary to banish the car through all high-speed ranges and various loadings on the engine, trying to support frequency of rotation of the last in a range 2500 ч 3500 rpm.

Function chart of system of distributed injection Bosch Motronic МР5.1

1 — ECU
2 — Gauge VMT (turns of a cranked shaft)
3 — the Gauge of pressure of soaked up air
4 — the Potentiometer of an axis throttle заслонки
5 — the Gauge of temperature of a cooling liquid
6 — the Gauge of temperature of soaked up air (IAT)
7 — the Gauge of speed (VSS)
8 — the Oxygen gauge (l-probe)
9 — the Battery
10 — the Dual relay
11 — the ignition Coil
12 — the Fuel tank

13 — the Fuel pump
14 — the Fuel filter
15 — the Fuel highway and the inlet pipeline
16 — a pressure Regulator
17 — injection Injectors
18 — the Coal adsorber
19 — the Valve of a purge of a coal adsorber
20 — the throttle Case
21 — the Gauge of heating of a throttle
22 — the Valve of additional air
23 — the Control lamp of system of self-diagnostics
24 — the Diagnostic socket

The scheme of giving of air in the engine


1 — the Air cleaner/cover of a head of cylinders 2 — the Site of an injector of injection	3 — the Inlet air path 4 — the Inlet pipeline 5 — the throttle Case

Function chart of system of distributed injection Magneti-Marelli 8Р

1 — ECU
2 — the Fuel tank
3 — Pogruzhnoj the fuel pump
4 — the Dual relay of system of injection (ECU/pump)
5 — the Fuel filter
6 — injection Injectors
7 — a pressure Regulator
8 — the Fuel highway
9 — the throttle Case
10 — the Potentiometer of an axis throttle заслонки
11 — the Step-by-step motor of adjustment of turns of idling
12 — the Oxygen gauge (l-probe)
13 — Gauge MAR

14 — the Gauge of temperature of a cooling liquid
15 — the Gauge of position of a cranked shaft
16 — the ignition Coil
17 — the Battery
18 — the ignition Switch
19 — the Control lamp of system of self-diagnostics
20 — the Diagnostic socket
21 — Gauge IAT
22 — the detonation Gauge
23 — the Heating element of the throttle chamber
24 — the Electromagnetic valve of a purge of a coal adsorber
25 — the Coal adsorber
26 — VSS
27 — Spark plugs

Function chart of system of distributed injection Bosch Motronic МР3.2

1 — ECU
2 — the Gauge of turns of the engine (on a flywheel)
3 — the Potentiometer of an axis throttle заслонки
4 — the Gauge of temperature of a cooling liquid
5 — Gauge IAT
6 — the Gauge of position of pistons in cylinders (CYP)
7 — the Oxygen gauge (l-probe)
8 — the detonation Gauge
9 — VSS
10 — the Dual relay
11 — the ignition Module
12 — ignition Coils
13 — the Fuel tank
14 — the Fuel pump
15 — the Fuel filter

16 — a pressure Regulator
17 — injection Injectors
18 — the Valve of a purge of a coal adsorber
19 — the Coal adsorber
20 — the Valve of additional air
21 — the throttle Case
22 — the Heating element of the throttle chamber
23 — the Electromagnetic valve of switching of system of giving of air
24 — the Vacuum pump
25 — Pneumatic capsules of system of giving of air
26 — the Inlet pipeline
27 — the Control lamp of system of self-diagnostics
28 — the Diagnostic socket
29 — the Battery

System Bosch Motronic MR5.1 (models 1.8 of l with РКПП)

The control system of engine Bosch Motronic MR5.1 (the Function chart of system of distributed injection Bosch Motronic МР5.1 see an illustration) is used at a complete set of models 1.8 of l with РКПП. The system which structure includes каталитический the converter of the closed contour and system of catching of fuel evaporations, answers the latest standards of protection of environment. The detailed information on functioning of responsible installation of ignition of a part of system is resulted in the Head an engine Electric equipment. The principle of giving of fuel in the engine is described more low.

The fuel pump shipped in a petrol tank carries out fuel giving in a fuel highway of system of injection. The linear fuel filter preventing a contamination of injectors is included in a path of giving of fuel. The pressure of giving of fuel is supervised by the regulator of pressure established in a fuel highway. If pressure in the power supply system rises above a preset value, the regulator provides return of surplus of fuel back in a petrol tank. All four injectors open simultaneously at each turn of a cranked shaft and provide fuel injection in the inlet pipeline.

The electric control system consists from ECU and a set of information gauges:
   a) the Potentiometer throttle заслонки - informs ECU on position заслонки and degrees of opening of a throttle;
   b) the Gauge of temperature of a cooling liquid - informs ECU on engine temperature;
   c) the Gauge of temperature of soaked up air (IAT) - informs ECU on temperature of air passing through the case of a throttle;
   d) the l-probe - informs ECU on level of the maintenance of oxygen (О2) in the fulfilled gases (Systems of decrease in toxicity and release of the fulfilled gases more in detail see);
   e) the Gauge of position of a cranked shaft - informs ECU on position of a cranked shaft and frequency of its rotation;
   f) the Gauge of absolute pressure in the inlet pipeline (МАР) - informs ECU to loading size on the engine (on depth of depression in the inlet pipeline);
   g) the Gauge of speed (VSS) - informs ECU on speed of movement of the car.

ECU, on the basis of the analysis of the signals arriving from information gauges, defines optimum structure of an air-fuel mix by the current moment time and corrects it by adjustment of duration of opening of injectors of injection. Thus, the mix structure is constantly supervised ECU and all time answers current operating conditions of the engine (warming up, single turns, movement with cruiser speed, acceleration, braking by the engine, etc., etc.).

ECU carries out also a complete control over idling turns through the valve of additional air in case of need providing possibility перепускания of soaked up air bypassing a throttle. At closed throttle заслонке ECU operates valve opening, regulating thereby air giving in the inlet pipeline and supporting at demanded level engine turns.

Besides the listed functions, ECU exercises administration of functioning of systems of release and catching of fuel evaporations (Systems of decrease in toxicity and release of the fulfilled gases see).

The throttle case is equipped by an electric heating element power supplies giving on which also supervises ECU, carrying out heating of the throttle chamber at cold starts and preventing an icing throttle заслонки.

Air moves in cylinders through four inlet channels with various cross-section section (consistently increasing). Air giving is regulated throttle заслонкой. The air filter is built in a head of cylinders and its cover simultaneously serves as a head cover (the Scheme of giving of air in the engine see an illustration). Besides a filtration of air the air cleaner serves also as an oil separator for tap картерных gases.

In case of infringement of serviceability of functioning of any of information gauges, ECU automatically passes in a mode of the closed contour. The false data thus arriving from the faulty gauge is ignored and instead of them some is used put in memory of the block of management average value of under control parametre. Efficiency of functioning thus, remaining quite adequate, can decrease a little. System transition in a mode of the closed contour is accompanied by inclusion of the control lamp built in in an instrument guard. In the block of memory ECU the corresponding code of malfunction registers.

At operation of a control lamp the car at the first possibility should be driven away on a car repair shop where full diagnostics of a control system by the engine with use of the special electronic input reader will be made. The diagnostic socket for input reader connection is located near to the assembly block of safety locks on the panel of devices of the car.

System Magneti-Marelli 8Р (l models 1.6, 1.8 l [with АТ] and 2.0 l [except RFY])

The control system of engine Magneti-Marelli 8Р (the Function chart of system of distributed injection Magneti-Marelli 8Р see an illustration) is used on l models 1.6, 1.8 l with АТ and 2.0 l with 8-klapannymi engines. The information on functioning of responsible installation of ignition of a part of system is resulted in the Head an engine Electric equipment.

The system by a functioning principle is very close to described above Bosch МР5.1. Unique difference is made by a control system of idling turns.

In system Magneti-Marelli ECU exercises administration of turns of idling by means of the special step-by-step motor established on the case of a throttle. The motor is equipped by a pusher supervising degree of opening of the bypass channel, on which air перепускается in the inlet pipeline bypassing the throttle chamber. At closed throttle заслонке ECU exercises administration of air giving in the inlet pipeline by means of the step-by-step motor, providing the control over idling turns. The perepusknoj channel is used also as a source of additional air at cold starts of the engine.

System Bosch Motronic MR3.2 (model 2.0 of l RFY)

The given system (the Function chart of system of distributed injection Bosch Motronic МР3.2 see an illustration) is used on models 2.0 of l with 16-klapannymi engines (RFY) and in the present Management to detailed consideration is not subject. We will notice only that many components carry out the same functions that the same components of system Magneti-Marelli, taking into account listed below differences.

Injection injectors in the distributive pipeline have individual management. Fuel is injected into cylinders by turns through each two turns of a cranked shaft.

The regulator of pressure of fuel provides a constant pressure in 3 bar at any modes of operation of the engine.

The system of an admission of air 16-klapannyh engines RFY has a special design. We will not go deep in particular functioning of the inlet pipeline, we will specify only that the pipeline consists of two channels of various length and various cross-section section. The given system allows to achieve increase in a twisting moment of the engine at low turns.

ECU provides a fuel stopping delivery at movement накатом on turns more low 1280 in a minute and renews a food at excess of the given value.

For protection of the engine against overloads fuel injection interrupts at excess by frequency of rotation of the engine of value in 6840 rpm. The gauge of turns is established on a head of cylinders.

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