# US 7,607,415 B2 · Method of crank signal disturbance compensation

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- Number: US 7,607,415 B2
- Document ID: US7607415B2
- Status: Granted
- Kind: B2
- Application number: 11/542,672
- Filed: 2006-10-03
- Published: 2008-04-03
- Granted: 2009-10-27
- Earliest claimed: 2006-10-03
- Assignees: GM Global Technology Operations LLC
- Inventors: David S. Mathews; Tameem K. Assaf; Ronald J. Kubani; David L. St. Pierre; Yong Xu
- Web page: https://patentgrep.com/patent/US7607415B2

## CPC

- F02D 41/0097: {using means for generating speed signals}
- F02D 41/009: {using means for generating position or synchronisation signals}
- G01P 3/489: Digital circuits therefor
- 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})

## Abstract

An engine system that compensates for disturbances in a crankshaft signal is provided. The system includes: an error module that computes an error between an ideal period and an actual period of a crankshaft signal; a correction factor module that determines a correction factor based on the error; and a compensation module that applies the correction factor to the actual period of the crankshaft signal.

## Claims

### Claim 1

An engine system that compensates for disturbances in a crankshaft signal, comprising:
an error module that computes an error between an ideal period and an actual period of a crankshaft signal;
a correction factor module that determines a correction factor based on the error; and
a compensation module that applies the correction factor to the actual period of the crankshaft signal,
wherein the error module computes the ideal period from a position equation,
wherein the error module determines an average period and an average angular acceleration for K number of reference periods, and
wherein the ideal period is computed from an initial angular velocity, the average period, and the average angular acceleration.

### Claim 2 (depends on 1)

The system of claim 1 wherein the correction factor module determines the correction factor (tCORRECTION) based on the error (tERROR), the actual period (tACTUAL), and the following equation:
t
CORRECTION
=
1
+
t
ERROR
t
ACTUAL
.

### Claim 3 (depends on 1)

The system of claim 1 wherein the correction factor module stores the correction factor in a lookup table accessed by engine speed and cylinder identification.

### Claim 4 (depends on 1)

The system of claim 1 wherein the error module computes the ideal period (tIDEAL) based on two coefficients (A and B), an the average period (tAVERAGE), an the initial angular velocity (vINITIAL), and an the average angular acceleration (aAVERAGE) and the following equation:
tIDEAL=tAVERAGE−A*vINITIAL−B*aAVERAGE.

### Claim 5 (depends on 4)

The system of claim 4 wherein the coefficient A is predetermined based on a the number of reference periods K and the following equation:
A
=
∑
x
=
0
k
-
1
⁢
x
k
.

### Claim 6 (depends on 4)

The system of claim 4 wherein the coefficient B is predetermined based on a the number of reference periods K and the following equation:
B
=
∑
x
=
0
k
-
1
⁢
1
/
2
⁢
x
2
k
.

### Claim 7

A method of compensating for disturbances in a crankshaft signal, comprising:
determining an actual period, an angular velocity, and an angular acceleration for K reference periods from a crankshaft position signal;
computing an ideal period of rotation based on the actual period, the angular velocity, and the angular acceleration for the K reference periods;
generating an error term for each of the K reference periods based on the ideal period and the corresponding actual period;
computing a correction factor for each of the K reference periods based on the error term; and
applying the correction factor based on the error term of the corresponding actual period to compensate for disturbances in the crankshaft signal.

### Claim 8 (depends on 7)

The method of claim 7 further comprising:
computing an average period and an average angular acceleration for the K reference periods; and
computing the ideal period of rotation based on the average period, an angular velocity of an initial reference period of the K reference periods, the average angular acceleration, and two predetermined coefficients (A and B).

### Claim 9 (depends on 8)

The method of claim 8 wherein the coefficient (A) is predetermined based on the number (K) of predetermined reference periods and the following equation:
A
=
∑
x
=
0
k
-
1
⁢
x
k
.

### Claim 10 (depends on 8)

The method of claim 8 wherein the coefficient (B) is predetermined based on the number (K) of predetermined reference periods and the following equation:
B
=
∑
x
=
0
k
-
1
⁢
1
/
2
⁢
x
2
k
.

### Claim 11 (depends on 7)

The method of claim 7 further comprising generating the error term (tERROR) for each (x) of the K reference periods based on the ideal period (tIDEAL), the actual period (tACTUAL), and the following equation:
tERROR(x)=tIDEAL−tACTUAL(x).

### Claim 12 (depends on 7)

The method of claim 7 further comprising computing the correction factor based on the error term (tERROR), the actual period (tACTUAL), and the following equation:
t
CORRECTION
⁡
(
x
)
=
1
+
t
ERROR
⁡
(
x
)
t
ACTUAL
⁡
(
x
)
.

### Claim 13 (depends on 7)

The method of claim 7 further comprising storing the correction factor in a lookup table accessed by engine speed and cylinder identification.

### Claim 14 (depends on 7)

The method of claim 7 further comprising computing the ideal period of rotation based on an average of computed periods wherein a period is computed for each of the K reference periods based on an actual period of an initial reference period of the K reference periods, an angular velocity of an initial reference period of the K reference periods, and an average angular acceleration.

### Claim 15 (depends on 7)

The method of claim 7 further comprising generating a crankshaft signal from a sensor sensing a rotational position of a wheel coupled to a crankshaft.