Method and devices for avoiding knocking on failure of an anti-knock regulator

• US 20040020462A1
• Filed: 08/25/2003
• Published: 02/05/2004
• Est. Priority Date: 07/29/2000
• Status: Active Grant

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Sauler, Jurgen, Torno, Oskar, Haeming, Werner, Kluth, Carsten, Heinstein, Axel
• Granted Patent: US 6,814,048 B2
• Time in Patent Office: Days
• US Class Current: 123/406.16
• CPC Class Codes: F02D 35/027 using knock sensors
• CPC Class Codes: F02D 41/222 relating to the failure of sensors or parameter detection devices
• CPC Class Codes: F02D 41/402 Multiple injections
• CPC Class Codes: F02P 5/1526 with means for taking into account incorrect functioning of the pinking sensor or of the electrical means
• CPC Class Codes: Y02T 10/40 Engine management systems

Abstract

A device having a monitoring circuit for a knock control and a control circuit (10) which initiates substitute measures in the event of a fault in the knock control, depending on the output signal (f) of the monitoring circuit, is described. The control unit is designed, for example, so that the number of fuel injection operations per operating cycle of a cylinder of the engine is increased as the substitute measure.

Claims

1. A method of preventing knocking in the event of failure of a knock control, in which a firing angle and/or ignition time of an engine having direct injection is regulated by using a knock control to prevent knocking during engine operation,

in fault-free operation of the knock control, fuel is injected into the combustion chamber of a cylinder of the engine at least once per operating cycle,

and the combustion is monitored by the knock control,

wherein in the event of a disturbance in the knock control, the quantity of fuel injected and/or the number of injection operations per operating cycle is altered.

2. The method as recited in claim 1,

wherein in the event of a disturbance in the knock control of a gasoline engine, fuel is injected at least once more per operating cycle of the cylinder than in fault-free operation of the knock control.

3. The method as recited in claim 1 or 2,

wherein in the event of a disturbance in the knock control, the firing angle and/or the ignition time is controlled as a function of the operating point of the engine, e.g., the rotational speed and/or load.

4. A device for preventing knocking in the event of failure of a knock control,

having a monitoring circuit for a knock control, which regulates a firing angle and/or ignition time of an engine having direct injection,

and having a control unit (10) which initiates substitute measures to prevent knocking in the event of a fault in the knock control, depending on the output signal (f) of the monitoring circuit,

wherein the control unit (10) is designed so that as a substitute measure, the injection quantity and/or the number of injection operations of fuel per operating cycle of a cylinder of the engine is altered.

5. The device as recited in claim 4,

wherein the number of injection operations per operating cycle is increased as a substitute measure in a gasoline engine.

6. The device as recited in claim 4 or 5,

wherein the control unit (10, 26) controls the firing angle and/or the ignition time as a function of the operating point of the engine, e.g., the rotational speed and/or load.

7. The device as recited in claim 6,

wherein the control unit (10) contains a first switching unit (24) which switches over as a function of the output signal (f) of the monitoring circuit,

the control unit (10) contains a second switching unit (30) which is connected at the input side to the output of the first switching unit (24) and switches over as a function of a signal (kr) which signals the knock control.

8. The device as recited in claim 7,

wherein for generating the switching signal (38) for the first switching unit (24), the control unit (10) contains a logic element (20) at whose inputs the output signal (f) of the monitoring circuit and a control signal (hks) are applied, signaling the transition to the substitute measure,

and the output of the logic element (20) is connected to a switching input of the first switching unit (24), preferably with the insertion of a NOT element (22).

9. The device as recited in one of claims 4 through 8,

wherein the control unit (10) contains an additional logic unit (12) at whose inputs the output signal (f) of the monitoring circuit and a signal (kr) which signals the knock control are applied,

and the output of the additional logic unit (12) is connected to a unit for controlling the injection operations.