Method for cleaning injectors of a direct-injection controlled-ignition engine

Abstract

The invention relates to a method for cleaning injectors of a direct-injection controlled-ignition engine, whereby, when the said engine is operating at no load, the maximum fuel pressure at the injector is calculated first of all with a view to cleaning, by executing, for at least one predetermined engine operating speed, an iterative loop during each iteration of which the value of the pressureof the injected fuel is incremented by a predetermined value and the corresponding injection time at the said incremented pressure is determined so as to select, for each operating speed, a cleaning pressure equal either to the maximum fuel pressure that corresponds to an injection time longer than the calibrated minimum injection time determined for the said operating speed, or to a ceiling maximum pressure corresponding to a determined calibrated pressure for the engine / injectors system, if this calibrated pressure is reached while the iterative loop is being executed. Next, a cleaning treatment is applied that consists in selecting an operating speed that allows the maximum cleaning pressure, and in commanding the engine to operate with this speed applied and by programming the said cleaning pressure, for a treatment duration greater than the operating time permitted during running under such operating conditions.

Description

technical field [0001] The invention relates to a method for cleaning an injector of a direct injection controlled ignition engine. Background technique [0002] The injection holes of the injectors of direct-injection controlled-ignition engines often have reduced cross-sections of the fuel passages due to clogging of the injection holes, which is usually caused by the deposition of carbonaceous substances called soot . [0003] The effect of this clogging phenomenon is to reduce the amount of fuel actually injected relative to the amount calculated and controlled by the engine's central control unit (called Engine Control Unit or ECU). To mitigate this reduction, vehicles are equipped with a richness controller that operates on measurements provided by an oxygen probe, commonly referred to as a lambda probe, placed in the exhaust line and designed to increase injection Time to make the injected fuel quantity consistent with the fuel quantity calculated by ECU. However, ...

AI Technical Summary

Problems solved by technology

However, this compensation comes with worsening pollution

Also, beyond a certain clogging rate, the required corrections cannot be made and this leads to a reduction in engine performance (excessive consumption, loss of torque) as perceived by the driver

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