Method for precise synchronization of a combustion engine

Patent metadata

Field	Value
Publication number	US-2018372010-A1
Application number	US-201616062363-A
Country	US
Kind code	A1
Filing date	Dec 12, 2016
Priority date	Dec 17, 2015
Publication date	Dec 27, 2018
Grant date	—

Abstract

An exact synchronization method for determining an angular position of an engine, modulo one engine cycle, by a crankshaft sensor and of at least one camshaft sensor. The method includes: estimating a continuous estimated interval assumed to contain the angular position, on receipt of a “marker” event, determining an angular position corresponding to each one of the possible occurrences of this “marker”, comparing the determined angular position with the estimated interval. If exactly one of the determined angular positions belongs to the estimated interval, then this angular position is the angular position of the engine. And an engine control method using such a method.

First claim

1 . An exact synchronization method for determining an angular position of an engine, modulo one engine cycle, by a crankshaft sensor comprising a crankshaft detector facing a crankshaft toothed wheel, performing two revolutions per engine cycle, and comprising a large number of regular teeth and at least one marker, the crankshaft detector being able to produce a “tooth” event corresponding to each of said teeth, and a “marker” event for a marker, and at least one camshaft sensor, each camshaft sensor comprising a camshaft detector facing a camshaft toothed wheel, performing one revolution per engine cycle, and comprising a small number of teeth, advantageously irregular, a camshaft detector being able to produce a “start of tooth” event for each rising edge and/or an “end of tooth” event for each falling edge, the method comprising:
estimating a continuous estimated interval assumed to contain the angular position,
on receipt of a “marker” event, determining an angular position corresponding to each one of the possible occurrences of this marker, and
comparing the determined angular positions with the estimated interval:
if none of the determined angular positions belongs to the estimated interval, or if more than one of the determined angular positions belongs to the estimated interval, then exact synchronization is not achieved,
if exactly one of the determined angular positions belongs to the estimated interval (IP), then this angular position is the angular position of the engine, and exact synchronization is achieved.

2 . The method as claimed in claim 1 , wherein, in the comparison step, the estimated interval is replaced by the estimated interval increased by a tolerance margin.

3 . The method as claimed in claim 2 , wherein the tolerance margin is equal to a portion of the angular span of a variable-timing device.

4 . The method as claimed in claim 1 , wherein the estimated interval from the estimation step is used in the comparison step only if its span is below a validation threshold.

5 . The method as claimed in claim 1 , applying, in parallel, an alternative exact synchronization method, which may prove slower, but has to be convergent.

6 . The method as claimed in claim 1 , wherein as long as exact synchronization is not achieved, the method reiterates the estimation and comparison operations.

7 . An engine control method, wherein the method uses an estimated synchronization method that produces a continuous estimated interval in order to command an injection of fuel, and an exact synchronization method as claimed in claim 1 to command ignition.

8 . The method as claimed in claim 7 , wherein the estimated synchronization method is merged with the estimation step of the exact synchronization method.

9 . The method as claimed in claim 7 , wherein injection is permitted only if the span of the continuous estimated interval is below a threshold.

10 . The method as claimed in claim 7 , wherein injection is forbidden if the comparison step does not conclude that exact synchronization has been achieved.

11 . The method as claimed in claim 3 , wherein the portion of the angular span is 75%.

12 . The method as claimed in claim 8 , wherein injection is permitted only if the span of the continuous estimated interval is below a threshold.

13 . The method as claimed in claim 8 , wherein injection is forbidden if the comparison step does not conclude that exact synchronization has been achieved.

14 . The method as claimed in claim 9 , wherein injection is forbidden if the comparison step does not conclude that exact synchronization has been achieved.

15 . The method as claimed in claim 7 , wherein injection is permitted only if the span of the continuous estimated interval is equal to the validation threshold.

16 . The method as claimed in claim 8 , wherein injection is permitted only if the span of the continuous estimated interval is equal to the validation threshold.

Assignees

• Continental Automotive France
• Continental Automotive Gmbh

Inventors

• Zouboff Pierre
• Lefevre Julien

Classifications

• F02D41/009 Primary

  using means for generating position or synchronisation signals · CPC title

• F02D41/062

  for starting (F02D41/061 takes precedence) · CPC title

• F02D13/0215

  changing the valve timing only · CPC title

• F02D2041/001

  for engines with variable valve actuation · CPC title

• F02D2400/08

  Redundant elements, e.g. two sensors for measuring the same parameter · CPC title