Method of checking the operability of the variable valve control in an internal combustion engine

• US 6,213,068 B1
• Filed: 12/10/1999
• Issued: 04/10/2001
• Est. Priority Date: 12/11/1998
• Status: Expired due to Fees

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Hassdenteufel, Armin
• Primary Examiner(s): Lo, Weilun
• Application Number:
  US09/457,871
• Time in Patent Office: 487 Days
• Field of Search: 123/90.11, 123/90.12, 123/90.13, 123/90.14, 123/90.15, 123/90.16, 123/90.17, 123/90.18, 123/198.D, 731/16, 731/172, 731/173, 731/181, 731/182
• US Class Current: 123/90.15
• CPC Class Codes: F01L 1/34 characterised by the provision of means for changing the timing of the valves without changing the duration of opening and without affecting the magnitude of the valve lift
• CPC Class Codes: F02D 13/0207 changing valve lift or valve lift and timing
• CPC Class Codes: F02D 13/0226 changing valve lift or valve lift and timing
• CPC Class Codes: F02D 2041/001 for engines with variable valve actuation
• CPC Class Codes: F02D 2200/0402 the parameter being determined by using a model of the engine intake or its components
• CPC Class Codes: F02D 41/1443 with one sensor per cylinder or group of cylinders
• CPC Class Codes: F02D 41/18 by measuring intake air flow
• CPC Class Codes: F02D 41/22 Safety or indicating devices for abnormal conditions in air/fuel ratio feedback systems F02D41/1495, in electric control linkage F02D11/107, in purge control systems F02M25/0809
• CPC Class Codes: Y02T 10/12 Improving ICE efficiencies
• CPC Class Codes: Y02T 10/40 Engine management systems

Abstract

The invention is directed to a method for checking the operability of a variable valve control in an internal combustion engine having an intake manifold and wherein the state of the variable valve control contributes to determining the combustion chamber charge. A first signal is provided and is indicative of the air mass actually drawn in by the engine via the intake manifold. A primary signal (HLS) for the combustion chamber charge is formed from the first signal. A second signal is formed from a desired value for the state of the variable valve control and at least one of the following: the position of a throttle flap, the pressure in the intake manifold and the rpm of the engine. An ancillary signal (NLS) for the combustion chamber charge is formed from the second signal. The primary and ancillary signals (HLS, NLS) are compared and an index is formed for the deviation of the primary and ancillary signals (HLS, NLS) from each other. A fault signal is outputted and/or stored when the index exceeds a predetermined value.

Claims

1. A method for checking the operability of a variable valve control in an internal combustion engine having an intake manifold and wherein the state of the variable valve control contributes to determining the combustion chamber charge, the method comprising the steps of:

providing a first signal indicative of the air mass actually drawn in by said engine via said intake manifold;

forming a primary signal (HLS) for the combustion chamber charge from said first signal;

providing a second signal formed from a desired value for the state of said variable valve control and at least one of the following;

the position of a throttle flap, the pressure in said intake manifold and the rpm of said engine;

forming an ancillary signal (NLS) for the combustion chamber charge from said second signal;

comparing said primary and ancillary signals (HLS, NLS) and forming an index for the deviation of said primary and ancillary signals (HLS, NLS) from each other; and

,

outputting and/or storing a fault signal when said index exceeds a predetermined value.

2. The method of claim 1, wherein said engine has at least two different cylinder groups having respective lambda control loops corresponding thereto and said engine having a load detecting arrangement common to both of said cylinder groups;

and, wherein;

when the comparison of said primary and ancillary signals indicates a fault, comparing the corrective factors of said lambda control loops to obtain a comparison result; and

, drawing a conclusion from said comparison result as to which of the cylinder groups has a fault.

3. The method of claim 1, wherein the check as to the operability of the variable valve control is activated only ip specific operating regions of said engine.