Method for controlling and regulating the fuel pressure in the common rail of an internal combustion engine

摘要

Proposed is a method for controlling and regulating an internal combustion engine (1), in which the rail pressure (pCR) is controlled via a suction throttle (4) on the low pressure side as a first pressure-adjusting element in a rail pressure control loop. The invention is characterized in that a rail pressure disturbance variable (VDRV) is generated in order to influence the rail pressure (pCR) via a pressure control valve (12) on the high pressure side as a second pressure-adjusting element, by means of which fuel is redirected in a controlled manner from the rail (6) into a fuel tank (2), the rail pressure disturbance variable (VDRV) being calculated using a corrected target volume flow (Vk(SL)) of the pressure control valve (12).

主权项

1. A method for open-loop and closed-loop control of an internal combustion engine, comprising the steps of: automatically controlling rail pressure (pCR) in a closed-loop rail pressure control system by a suction throttle on a low-pressure side as a first pressure regulator; controlling a pressure control valve on a high-pressure side as a second pressure regulator, by which fuel is redirected from the rail into a fuel tank, to generate a rail pressure disturbance variable (VDRV) for influencing the rail pressure (pCR); computing the rail disturbance variable (VDRV) based on a corrected set volume flow (Vk(SL)) of the pressure control valve; computing the corrected set volume flow (Vk(SL)) from a static set volume flow (Vs(SL)) and a dynamic set volume flow (Vd(SL)); computing the dynamic set volume flow (Vd(SL)) of the pressure control valve by a dynamic correction unit as a function of a set rail pressure (pCR(SL)) and an actual rail pressure (pCR(IST); and computing the dynamic set volume flow (Vd(SL)) by computing a resultant control deviation (epRES) of the rail pressure (pCR) and, if the resultant control deviation (epRES) is less than zero (epRES<0), then setting the dynamic set volume flow (Vd(SL)) to a value of zero or, if the resultant control deviation (epRES) is greater than or equal to zero (epRES≧0), then setting the dynamic set volume flow (Vd(SL)) to a value of a product of the resultant control deviation (epRES) and a factor, wherein a position of the pressure control valve is controlled based on the corrected set volume flow (Vk(SL)).