Method for automatic pressure control

• US 7,856,961 B2
• Filed: 08/04/2009
• Issued: 12/28/2010
• Est. Priority Date: 08/04/2008
• Status: Active Grant

• Current Assignee: Rolls-Royce Solutions GmbH (Rolls-Royce Holdings Plc)
• Original Assignee: MTU Friedrichshafen GmbH (Rolls-Royce Holdings Plc)
• Inventors: Prothmann, Michael, Doelker, Armin
• Primary Examiner(s): Cronin; Stephen K
• Assistant Examiner(s): Najmuddin; Raza
• Application Number:
  US12/535,142
• Publication Number:
  US 20100024773A1
• Time in Patent Office: 511 Days
• Field of Search: 123/357, 123/445, 123/446, 123/447, 123/457, 123/458, 123/481, 123/198.F, 123/198.DB, 123/497, 123/575, 123/456, 123/472, 123/478, 123/480, 123/696, 123/54.4, 701/102, 701/103, 701/104, 138/26, 138/30
• US Class Current: 123/456
• CPC Class Codes: F02D 2041/2027 Control of the current by pulse width modulation or duty cycle control
• CPC Class Codes: F02D 2250/31 Control of the fuel pressure
• CPC Class Codes: F02D 31/007 controlling fuel supply
• CPC Class Codes: F02D 41/0082 per groups or banks F02D41/0087 takes precedence
• CPC Class Codes: F02D 41/3854 with elements in the low pressure part, e.g. low pressure pump

Abstract

A method for automatically controlling the pressure of a common rail system on an A side and a common rail system on a B side of a V-type internal combustion engine, in which the rail pressure (pCR(A)) of the common rail system on the A side is automatically controlled by an A-side closed-loop pressure control system, and the rail pressure (pCR(B)) of the common rail system on the B side is automatically controlled by a B-side closed-loop pressure control system. The automatic control of each side is independent of the other. A common set rail pressure is set as a reference input for both closed-loop pressure control systems. A set injection quantity is computed by a speed controller as a function of an actual speed relative to a set speed, and a common disturbance variable is computed as a function of the set injection quantity. Both the correcting variable of the A-side pressure controller and the correcting variable of the B-side pressure controller are corrected by the common disturbance variable.

Claims

1. A method for automatically controlling pressure of a common rail system on an A side and a common rail system on a B side of a V-type internal combustion engine, comprising the steps of:

automatically controlling rail pressure (pCR(A)) of the common rail system on the A side by an A-side closed-loop pressure control system, the common rail system on the A side having at least one injector;

automatically controlling rail pressure (pCR(B)) of the common rail system on the B side by a B-side closed-loop pressure control system, the common rail system on the B side having at least one injector, the automatic control of each side being independent of the other, including setting a common set rail pressure (pSL) as a reference input for both closed-loop pressure control systems; and

computing a set injection quantity (QSL) by a speed controller as a function of an actual speed (nIST) relative to a set speed (nSL), computing a common disturbance variable (VSRG) as a function of the set injection quantity (QSL), and correcting both a correcting variable (V(A)) of the A-side pressure controller and a correcting variable (V(B)) of the B-side pressure controller using the common disturbance variable (VSRG).

2. The method in accordance with claim 1, wherein the common disturbance variable (VSRG) corresponds to a static disturbance variable (VSTAT), which is computed from the product of the set injection quantity (QSL), the actual speed (nIST), the number of cylinders (ZYL), and factors (F1, F2).

3. The method in accordance with claim 2, wherein the common disturbance variable (VSRG) is a dynamic disturbance variable, which is computed from the static disturbance variable (VSTAT) by a PDT1 element.

4. The method in accordance with claim 1, and further comprising providing a closed-loop current control system, which is subordinate to both the A-side closed-loop pressure control system and the B-side closed-loop pressure control system, for automatically controlling the regulating current of a suction throttle.

5. The method in accordance with claim 1, wherein the common set rail pressure (pSL) is preset as a constant value.

6. The method in accordance with claim 1, wherein the common set rail pressure (pSL) is computed as a function of a set torque.

7. The method in accordance with claim 1, wherein the common set rail pressure (pSL) is computed as a function of the set injection quantity (QSL) and the actual speed (nIST).