# US 10,371,072 B2 · Method and device for detecting reverse rotation of an internal combustion engine

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- Number: US 10,371,072 B2
- Document ID: US10371072B2
- Status: Granted
- Kind: B2
- Application number: 15/562,166
- Filed: 2016-04-14
- Published: 2018-03-22
- Granted: 2019-08-06
- Earliest claimed: 2015-04-16
- Assignees: Continental Automotive France; Continental Automotive GmbH
- Applicants: Continental Automotive France; Continental Automotive GmbH
- Inventors: Valerie Gouzenne Coutier
- Web page: https://patentgrep.com/patent/US10371072B2

## CPC

- F02D 41/009: {using means for generating position or synchronisation signals}
- F02D 41/0097: {using means for generating speed signals}
- F02D 41/04: Introducing corrections for particular operating conditions (F02D41/14 takes precedence)
- 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)}
- F02D 41/042: {for stopping the engine}
- F02D 2041/0095: {Synchronisation of the cylinders during engine shutdown}
- F02D 2200/101: Engine speed
- F02D 2250/06: Reverse rotation of engine
- G01P 3/481: of pulse signals
- G01P 13/045: {with speed indication}
- Y02T 10/40: Engine management systems
- 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)
- G01P: MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT (measuring or recording blood flow A61B5/02, A61B8/06; monitoring speed or deceleration of electrically-propelled vehicles B60L3/00; vehicle lighting systems adapted to indicate speed B60Q1/54; determining position or course in navigation, measuring ground distance in geodesy or surveying G01C; combined measuring devices for measuring two or more variables of movement G01C23/00; measuring velocity of sound G01H; measuring velocity of light G01J7/00; measuring direction or velocity of solid objects by reception or emission of radiowaves or other waves and based on propagation effects, e.g. Doppler effect, propagation time, direction of propagation, G01S; measuring speed of nuclear radiation G01T; measuring acceleration of gravity G01V; {measuring or recording the speed of trains B61L23/00; speed indicators incorporated in motor vehicles B60K35/00; measuring frequency or phase G01R; traffic control G08G})
- Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION

## Abstract

A toothed target rotationally fixed to a shaft of the engine includes a series of n real teeth, followed by m dummy teeth forming a reference zone. For each tooth k, the period of time separating the latter from the preceding tooth k−1 is measured. A signal exhibits at least one transition in level in a portion of the signal corresponding to the passage of the reference zone. A first and a second product are calculated for at least some of the values of k; the ratio between these two products is calculated; and the direction of rotation of the engine is detected, in case of correspondence of the ratio with a first noteworthy value and with a second noteworthy value which are representative, respectively, of rotation in a normal direction and rotation in a reverse direction.

## Claims

### Claim 1

A method for detecting the direction of rotation of an internal combustion engine, said engine being associated with:
a toothed target (3) rotationally fixed to a shaft (4) of the engine, said toothed target comprising a series of teeth comprising on the one hand n real teeth (31) which are regularly spaced, followed by m dummy teeth forming a reference zone (32) on the other hand, where n and m are non-zero integers;
a sensor (2) arranged to generate a substantially periodic sensor signal having active edges between a first signal level and a second signal level in response to the passage of the real teeth of the toothed target in front of said sensor; and
a management unit (1) configured to measure, for each tooth of index k in the series of teeth, the period of time, referred to as the period T(k) of the tooth k, separating said tooth k from the preceding tooth of index k−1 in the series of teeth; wherein,
the sensor signal further exhibiting at least one transition between the first signal level and the second signal level in a portion of the sensor signal corresponding to passage of the reference zone (32) of the toothed target in front of the sensor, the method comprises the following steps executed for at least some of the values of the index k associated with the teeth of the target:
a) calculation of a first product by multiplying N times the period T(k−N/2) of the tooth k−N/2, where N is an even integer equal to or greater than 2,
b) calculation of a second product by multiplying between themselves the periods T(k−i) of the teeth i, with i being between 0 and N/2−1, and between N/2+1 and N,
c) calculation of the ratio, denoted R′(k), between the first product and the second product, and
d) detection of the direction of rotation of the target, and therefore of the engine, in case of correspondence of the ratio R′(k) with a first noteworthy value and with a second noteworthy value which are representative, respectively, of rotation in a normal direction of rotation and of rotation in a reverse direction of rotation to said normal direction of rotation.

### Claim 2 (depends on 1)

The method as claimed in claim 1, wherein, N being equal to 2, the first noteworthy value of the sensor signal is equal to 9.

### Claim 3 (depends on 1)

The method as claimed in claim 1, wherein the transition of the sensor signal between the first signal level and the second signal level in the portion of said sensor signal corresponding to passage of the reference zone (32) of the toothed target in front of the sensor is such that a duty cycle of the sensor signal in said portion of the sensor signal is between 30% and 70% for rotation of the target in the forward direction of rotation.

### Claim 4 (depends on 3)

The method as claimed in claim 3, wherein, N being equal to 2 and the duty cycle of the sensor signal in said portion of the sensor signal being substantially equal to 50% for rotation of the target in the forward direction of rotation, the second noteworthy value of the sensor signal is equal to 4.

### Claim 5 (depends on 1)

The method as claimed in claim 1, wherein the number n is equal to 58 and the number m is equal to 2.

### Claim 6 (depends on 1)

The method as claimed in claim 1, wherein the steps a) to d) are carried out for all values of the index k associated with the teeth of the target.

### Claim 7 (depends on 6)

The method as claimed in claim 6, comprising determining, from the ratio R′(k), information representative of the position of the tooth of index k in relation to the reference zone.

### Claim 8 (depends on 1)

The method as claimed in claim 1, wherein the steps a) to d) are carried out for only some of the values of the index k associated with the teeth of the target, for which the value k=m.

### Claim 9 (depends on 1)

A device comprising means for implementing each of the steps of a processing method as claimed in claim 1.

### Claim 10 (depends on 9)

A system for managing an internal combustion engine, comprising:
a toothed target (3) rotationally fixed to a shaft (4) of the engine, said toothed target comprising a series of teeth comprising on the one hand n real teeth (31) which are regularly spaced, followed by m dummy teeth forming a reference zone (32) on the other hand, where n and m are non-zero integers;
a sensor (2) arranged to generate a substantially periodic sensor signal having active edges between a first signal level and a second signal level in response to the passage of the real teeth of the toothed target in front of said sensor; and
a management unit (1) configured to measure, for each tooth of index k in the series of teeth, the period of time, referred to as the period T(k) of the tooth k, separating said tooth k from the preceding tooth of index k−1 in the series of teeth; and
a device as claimed in claim 9.

### Claim 11 (depends on 10)

The system as claimed in claim 10, wherein the device is included in the management unit (1).

### Claim 12 (depends on 2)

The method as claimed in claim 2, wherein the transition of the sensor signal between the first signal level and the second signal level in the portion of said sensor signal corresponding to passage of the reference zone (32) of the toothed target in front of the sensor is such that a duty cycle of the sensor signal in said portion of the sensor signal is between 30% and 70% for rotation of the target in the forward direction of rotation.

### Claim 13 (depends on 2)

The method as claimed in claim 2, wherein the number n is equal to 58 and the number m is equal to 2.

### Claim 14 (depends on 3)

The method as claimed in claim 3, wherein the number n is equal to 58 and the number m is equal to 2.

### Claim 15 (depends on 4)

The method as claimed in claim 4, wherein the number n is equal to 58 and the number m is equal to 2.

### Claim 16 (depends on 2)

The method as claimed in claim 2, wherein the steps a) to d) are carried out for all values of the index k associated with the teeth of the target.

### Claim 17 (depends on 3)

The method as claimed in claim 3, wherein the steps a) to d) are carried out for all values of the index k associated with the teeth of the target.

### Claim 18 (depends on 4)

The method as claimed in claim 4, wherein the steps a) to d) are carried out for all values of the index k associated with the teeth of the target.

### Claim 19 (depends on 5)

The method as claimed in claim 5, wherein the steps a) to d) are carried out for all values of the index k associated with the teeth of the target.

### Claim 20 (depends on 2)

The method as claimed in claim 2, wherein the steps a) to d) are carried out for only some of the values of the index k associated with the teeth of the target, for which the value k=m.