Method for regulating the rail pressure in a common rail injection system of an internal combustion engine

Abstract

Proposed is a method for open-loop and closed-loop control of an internal combustion engine (1) in which the rail pressure (pCR) is controlled via a low pressure-side suction throttle (4), as the first pressure-adjusting element in a rail pressure control loop. The invention is characterized in that a rail pressure disturbance variable (VDRV) is generated to influence the rail pressure (pCR) via a high-pressure side pressure control valve (12), as the second pressure-adjusting element, by means of which fuel is redirected from the rail (6) into the fuel tank (2). The position of the high-pressure side pressure control valve (12) is determined by a PWM signal (PWMDV), which, when normal mode is set, is calculated as a function of the resulting target volume flow and, when protective mode is set, is temporarily set to a maximum value.

Description

technical field

[0001] The invention relates to a method for controlling and regulating an internal combustion engine according to the preamble of claim 1 . Background technique

[0002] In internal combustion engines with a common rail system, the quality of the combustion is decisively determined by the pressure level in the rail. The rail pressure is therefore regulated in order to comply with the legally prescribed emission values. Typically, a rail pressure regulation circuit comprises a comparator (Vergleichsstelle) for determining the regulation deviation, a pressure regulator (Druckregler) for computing the regulation signal (Stellsignal), a control system (Regelstrecke) and a circuit for computing the actual rail pressure Software filter (Software filter) in the feedback branch (Rückkopplungszweig). The adjustment deviation from the actual rail pressure is calculated from the target rail pressure. The controlled system includes a pressure control element (Druckst...

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