Electric generation control apparatus for vehicle alternator

• US 20070029977A1
• Filed: 07/13/2006
• Published: 02/08/2007
• Est. Priority Date: 08/03/2005
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Asada, Tadatoshi
• Granted Patent: US 7,292,008 B2
• Time in Patent Office: Days
• US Class Current: 322/24
• CPC Class Codes: H02J 7/2434 with pulse modulation
• CPC Class Codes: H02P 9/02 Details
• CPC Class Codes: Y02T 10/92 Energy efficient charging or discharging systems for batteries, ultracapacitors, supercapacitors or double-layer capacitors specially adapted for vehicles

Abstract

An electric generation control apparatus for a vehicle alternator receives an electric generation control signal transferred from an ECU placed apart from the control apparatus through a data transfer line. The control apparatus has a voltage comparator, a communication state judgment circuit, a serial data communication receiver, a PWM communication receiver, and an electric generation control circuit. The voltage comparator acts as a receiver of receiving the electric generation control signal transferred through the data transfer line. The communication state judgment circuit judges whether the received signal is a PWM signal or a serial data signal. The serial data communication receiver and the PWM communication receiver demodulate an electric generation control parameter from the received control signal based on the judgment result. The electric generation control circuit controls the operation of the vehicle alternator based on the electric generation control parameter demodulated.

Claims

1. An electric generation control apparatus configured to receive an electric generation control signal transferred from an external control device located apart from the electric generation control apparatus through a data transmission line and configured to control electric generation state of a vehicle alternator based on the received electric generation control signal, the electric generation control apparatus comprising:

a receiver configured to receive an electric generation control signal

transferred from the external control device through the data transmission line;

a judgment circuit configured to judge whether the electric generation control signal received by the receiver is a serial data signal or a pulse width modulation (PWM) signal;

a demodulation circuit configured to demodulate the electric generation control signal to an electric generation control parameter according to the judgment result of the judgment circuit; and

an electric generation control circuit configured to control the electric generation state of the vehicle alternator based on the electric generation control parameter demodulated by the demodulation circuit.

2. The electric generation control apparatus according to claim 1, wherein the serial data signal includes a synchronous break signal indicating the initiation of a data transmission of the serial data signal, and the synchronous break signal is one of a fixed low level and a fixed high level of a specified time, length, and

the judgment circuit judges that the electric generation control signal is the serial data signal when the time length of the level of the received electric generation control signal is shorter than the specified time length, and judges that the electric generation control signal is the PWM signal when the time length of the level of the received electric generation control signal is longer than the specified time length.

3. The electric generation control apparatus according to claim 2, wherein the demodulation circuit comprises:

a filter with a filter constant that is longer than the fixed time length of the synchronous break signal; and

a PWM demodulation circuit configured to demodulate the PWM signal output of the filter that receives the electric generation control signal.

4. The electric generation control apparatus according to claim 1, wherein the electric generation control apparatus transfers communication state information to the external control device, and

the receiver receives the serial data signal transferred from the external control device based on the communication state information indicating establishment of the serial data communication, and receives the PWM signal transferred from the external control device based on the communication state information indicating difficulty of establishment of the serial data communication.

5. The electric generation control apparatus according to claim 2, wherein the electric generation control apparatus transfers communication state information to the external control device, and

the receiver receives the serial data signal transferred from the external control device based on the communication state information indicating establishment of the serial data communication, and receives the PWM signal transferred from the external control device based on the communication state information indicating difficulty of establishment of the serial data communication.

6. The electric generation control apparatus according to claim 3, wherein the electric generation control apparatus transfers communication state information to the external control device, and

the receiver receives the serial data signal transferred from the external control device based on the communication state information indicating establishment of the serial data communication, and receives the PWM signal transferred from the external control device based on the communication state information indicating difficulty of establishment of the serial data communication.

9. The electric generation control apparatus according to claim 1, wherein the receiver comprises a voltage comparator configured to compare a voltage level of the input electric generation control signal with a reference voltage level.

7. An electric generation control apparatus for a vehicle alternator comprising:

an electric generation state transmitter configured to generate a serial data signal including an electric generation state signal indicating a state of the vehicle alternator, and to transfer the serial data signal through a data transmission line to an external control device located apart from the electric generation control apparatus;

a communication state judgment circuit configured to judge a communication state through the data transmission line; and

a diagnosis information setting circuit configured to instruct to the electric generation state transmitter so that the voltage of the data transmission line is fixed to a specified level in order to inform occurrence of abnormal state of the electric generation of the vehicle alternator to the external control device when the communication state judgment circuit judges difficulty of serial data transmission using the serial data signal.

8. The electric generation control apparatus according to claim 7, wherein the communication state judgment circuit judges the difficulty of the serial data transmission using the serial data signal when one of following conditions occurs:

(a) the abnormal state of the serial data communication is continued for a specified time length; and

(b) the number of the abnormal states of the electric generation of the vehicle alternator exceeds a specified number.