# US 2014/0156168 A1 · Method for controlling rail pressure

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- Number: US 2014/0156168 A1
- Document ID: US20140156168A1
- Status: Published application
- Kind: A1
- Application number: 14/125,230
- Filed: 2012-06-05
- Published: 2014-06-05
- Earliest claimed: 2011-06-10
- Assignees: MTU Friedrichshafen GmbH
- Inventors: Armin Dölker
- Web page: https://patentgrep.com/patent/US20140156168A1

## CPC

- F02D 41/14: Introducing closed-loop corrections
- F02D 41/3845: {by controlling the flow into the common rail, e.g. the amount of fuel pumped}
- F02D 2041/1432: {the system including a filter, e.g. a low pass or high pass filter}
- F02D 2041/286: {comprising means for signal processing}
- F02D 2041/3881: {with multiple common rails, e.g. one rail per cylinder bank, or a high pressure rail and a low pressure rail}
- F02D 2200/0602: Fuel pressure
- F02D: CONTROLLING COMBUSTION ENGINES (vehicle fittings, acting on a single sub-unit only, for automatically controlling vehicle speed B60K31/00; conjoint control of vehicle sub-units of different type or different function, road vehicle drive control systems for purposes other than the control of a single sub-unit B60W)

## Abstract

Proposed is a method for closed loop rail pressure control of a V-type internal combustion engine with an asymmetrical firing order, wherein an actual rail pressure is computed from the measured rail pressure; a system deviation is determined by means of the actual rail pressure and a set rail pressure; and wherein a correcting variable for actuating a pressure actuating element, in particular a suction throttle, for regulating the rail pressure is computed. The invention is characterized by the fact that the actual rail pressure is computed from the measured rail pressure by means of an averaging filter in that below a limit speed (nLi) the rail pressure is averaged over a constant time and in that above the limit speed (nLi) the rail pressure is averaged over a working cycle of the internal combustion engine.

## Claims

### Claim 1

A method for closed loop rail pressure control of a V-type internal combustion engine with an asymmetrical firing order, wherein an actual rail pressure is computed from the measured rail pressure; a system deviation is determined by means of the actual rail pressure and a set rail pressure; and wherein a correcting variable for actuating a pressure actuating element, in particular a suction throttle, for regulating the rail pressure is computed,
wherein the actual rail pressure is computed from the measured rail pressure with an averaging filter, and wherein the rail pressure is averaged over a constant time below a limit speed, and the rail pressure is averaged over a working cycle of the internal combustion engine above the limit speed.

### Claim 2 (depends on 1)

A method, as claimed in claim 1,
wherein the actual rail pressure is computed using a low-pass filter.

### Claim 3 (depends on 1)

A method, as claimed in claim 1,
wherein the rail pressure of the common rail system on a first side is regulated using a first-side closed loop rail pressure control circuit; and the rail pressure of the common rail system on a second side is regulated using a second-side closed loop rail pressure control circuit; and both closed loop rail pressure control circuits are automatically controlled independently of each other; and a common set rail pressure is established as the reference input variable for both closed loop rail pressure control circuits.

### Claim 4 (depends on 3)

A method, as claimed in claim 3,
wherein the common set rail pressure is computed as a function of:
a set torque or
the set injection quantity and the engine speed.

### Claim 5 (depends on 3)

A method, as claimed in claim 3, wherein the first side is an A-side of the engine, and the second side is a B-side of the engine.