7.1. System of ignition of the petrol engine
General information, security measures
General information
The system of ignition provides ignition of the air-fuel mix given to combustion chambers of cylinders. For formation of a spark of the required intensity the 12-volt tension of onboard power supply in will be transformed ignition coils to high-voltage (VV), - 30 000 Century.
On the KIA Sportage models considered in the present manual the electronic system of direct ignition (DIS) functioning under control of ECM which is guided by indications of sensors of provisions of cranked (CKP) and distributive (CMP) of shaft is used.
Analyzing information arriving from sensors, ECM defines the moment of readiness of each of engine cylinders for ignition of the air-fuel mix injected into it, - at the command of the ECM coil tension causing breakdown of a gap between electrodes of the corresponding candle develops VV.
Ignition coils
On considered in the present manual the models equipped with the DOHC engine two coils of ignition installed directly over spark plugs of the second and fourth cylinders are used. At the same time sparking at the command of ESM happens in at the same time two cylinders, the piston of one of which is in the end of a step of compression, another - at the end of a final step, and the main power failure is the share of a candle of the cylinder which is in a compression step in view of much more high pressure in it. Sparking power in the second cylinder will be minimum (a single spark), providing at the same time reburning of the molecules of air-fuel mix remaining in the combustion chamber that allows to achieve more effective decrease in toxicity of the fulfilled gases. Sparking happens at a time in cylinders 1/2 and 3/4.
Coils do not need regular service and in case of failure are subject to replacement.
Sensor of position of the camshaft (CMP)
The sensor is installed in a back part of a head of cylinders and traces position of the camshaft, giving the relevant information on the module of management.
Sensor of provision of a bent shaft (CKP)
The CKP sensor is fixed on a case of transmission and determines the frequency of rotation and the provision of a bent shaft by tracking of the moments of passing by the sensitive element of working ledges fixed on a flywheel / a driving disk of a gear ring.
Spark plugs
Spark plugs, when giving of tension VV on them from coils, provide the sparking caused by breakdown of an interelectrode gap, and leading to ignition of the air-fuel mix given to cylinders. Check of a condition of spark plugs should be made regularly, according to the Schedule of routine maintenance of the car (see the Head the Current leaving and service).
High-voltage (VV) electrical wiring
VV an electrical wiring is used for connection of coils of ignition with candles. Periodically check a condition of isolation and contact tips of VV of wires.
System of protection of the engine against a detonation
The high extents of compression, characteristic of modern engines, improving fuel profitability, and also change of quality of the used fuel increase tendency of the engine to a detonation. At high extents of compression detonation limits often are in the established range of the moments of ignition (for the minimum fuel consumption), or are shifted towards delay. Means of protection prevent detonation combustion of working mix under all operating conditions of the engine.
The sensor of a detonation (KS) fixed in the appropriate place of the engine reacts to the high-frequency fluctuations of casting of the block arising at a detonation and transforms them to the electric signals arriving on ECM.
The so-called "measuring window" is synchronized with rotation of a bent shaft, and for allocation of the data characterizing a detonation the strip filter is used. Entrance information is compared to the signals received at combustion of mix without detonation then ECM on several steps of the engine provides ignition moment shift towards delay, necessary for correction of a situation. Then installation comes back to reference optimum value. What is especially important, the shift of the moment of ignition can individually occur for each cylinder of the engine while the others continue to operate normally.
Security measures
At service of systems of direct ignition it is necessary to observe special precautionary measures:
- Do not touch an electrical wiring of system of ignition and do not disunite its contact sockets at the working engine / the rotating starter;
- Do not disconnect the battery at the working engine;
- Of sockets of an electrical wiring of sensors and modules of management you make Rassoyedineniye only after a preliminary detachment of the rechargeable battery;
- You make detachment/connection of an electrical wiring of system of ignition, and also connection/shutdown of any diagnostic and measuring equipment only at the switched-off ignition;
- Do not allow to performance of work on service by electronic system of ignition of people with the implanted pacemaker;
- Do not allow grounding of contact plugs of coils of ignition on weight at all;
- Do not connect a control lamp to plugs of coils of ignition.