System and method for optimizing engine performance

• US 6,516,780 B2
• Filed: 04/30/2001
• Issued: 02/11/2003
• Est. Priority Date: 11/13/2000
• Status: Expired due to Fees

• Current Assignee: Siemens VDO Automotive Corporation (Siemens AG)
• Original Assignee: Siemens VDO Automotive Corporation (Siemens AG)
• Inventors: Liu, Ching-Po
• Primary Examiner(s): SOLIS, ERICK R
• Application Number:
  US09/845,615
• Publication Number:
  US 20020056436A1
• Time in Patent Office: 652 Days
• Field of Search: 123/406.22, 123/406.27, 123/339.11, 123/406.41, 123/406.24, 123/406.14
• US Class Current: 123/406.22
• CPC Class Codes: F02D 2200/1015 Engines misfires
• CPC Class Codes: F02D 35/023 by determining the cylinder pressure
• CPC Class Codes: F02D 41/1498 measuring engine roughness
• CPC Class Codes: F02P 5/1508 with particular means during idling
• CPC Class Codes: F02P 5/153 dependent on combustion pressure
• CPC Class Codes: Y02T 10/40 Engine management systems

Abstract

An engine control system and method include determining which engine cylinder is performing at a level differently than a majority of the other cylinders. Whenever a cylinder output is below that of the other cylinders, an engine performance variable, such as the spark angle, preferably is adjusted to bring the cylinder indicated mean effective pressure into conformance with that of the other cylinders. By adjusting the individual cylinder performance variable, engine performance is brought to a desired level of smoothness, especially under conditions such as engine idle.

Claims

1. A method of controlling the operation of a multiple cylinder vehicle engine, comprising the steps of:

(A) determining an indicated mean effective pressure of each of the cylinders to monitor each cylinder for a misfire condition; and

(B) when a misfire condition exists, and adjusting a spark angle associated with a first one of the cylinder that includes an indicated mean effective pressure that is different from an indicated mean effective pressure at least one other of the cylinders to thereby alter the indicated mean effective pressure of the first cylinder.

2. The method of claim 1, including performing step (A) when the engine is operating at a selected level.

3. The method of claim 2, wherein the selected level is engine idle.

4. The method of claim 2, wherein the selected level includes a rate of RPM that is below a selected threshold.

5. The method of claim 1, wherein step (B) includes adjusting a plurality of spark angles associated with a respective plurality of cylinders.

6. The method of claim 1, including performing step (B) until all cylinders have the same indicated mean effective pressure.