Grill shutter device

1. A grill shutter device comprising:

a shutter mechanism adapted to be provided in a grill opening in a front portion of a vehicle body, wherein the shutter mechanism is operated to be opened and closed to control a rate of flow of an air flowing into the vehicle body;

an electronic control unit, which controls opening and closing operations of the shutter mechanism, wherein the electronic control unit is configured to

determine whether a vehicle is in a traveling end state;

detect an operation amount of the shutter mechanism by counting pulse signals that are in synchronization with the opening and closing operations of the shutter mechanism;

confirm that the shutter mechanism is in an open state based on the operation amount of the shutter mechanism when the vehicle is in the traveling end state; and

determine whether the pulse signals are normal, wherein

in a case where a previous operation of the shutter mechanism is an opening operation, the electronic control unit determines that the open state of the shutter mechanism cannot be confirmed if the operation amount in the opening operation is not a preset normal operation amount,

the electronic control unit determines that the open state of the shutter mechanism cannot be confirmed when determining that the pulse signals are not normal, and

the electronic control unit controls the shutter mechanism to open the shutter mechanism when the open state of the shutter mechanism is not confirmed.

2. The grill shutter device according to claim 1 , further comprising:

a pulse outputting portion, which outputs the pulse signals,

wherein the electronic control unit is configured to detect a fault of the pulse outputting portion.

3. The grill shutter device according to claim 1 , wherein in a case where the previous operation of the shutter mechanism is the opening operation, the electronic control unit determines that the open state of the shutter mechanism cannot be confirmed if the electronic control unit detects that the pulse signals have been changed after the opening operation.

4. The grill shutter device according to claim 1 , wherein the electronic control unit is configured to detect an operation position of the shutter mechanism,

wherein the electronic control unit confirms that the shutter mechanism is in the open state based on the operation position of the shutter mechanism.

5. The grill shutter device according to claim 4 , further comprising a limit switch provided corresponding to the open state of the shutter mechanism,

wherein the electronic control unit detects an operation position of the shutter mechanism that corresponds to the open state based on an operation state of the limit switch.

6. The grill shutter device according to claim 5 , wherein the electronic control unit is configured to detect a fault of the limit switch,

wherein the electronic control unit determines that the open state of the shutter mechanism cannot be confirmed when detecting a fault of the limit switch.

7. The grill shutter device according to claim 4 , wherein the electronic control unit is configured to detect the operation position as an absolute position.

8. The grill shutter device according to claim 7 , wherein the electronic control unit is configured to detect the absolute position by counting pulse signals, which are in synchronization with the opening and closing operations of the shutter mechanism, with a specific position as reference.

9. The grill shutter device according to claim 1 , wherein the electronic control unit is configured to measure operation time of the shutter mechanism,

wherein the electronic control unit confirms that the shutter mechanism is in the open state based on the operation time.

10. The grill shutter device according to claim 9 , wherein in a case where the previous operation of the shutter mechanism is an opening operation, the electronic control unit determines that the open state of the shutter mechanism cannot be confirmed if the operation time in the opening operation is not a preset normal operation time.

11. The grill shutter device according to claim 1 , wherein the electronic control unit determines that the open state of the shutter mechanism cannot be confirmed when the previous operation of the shutter mechanism is not the opening operation.

12. The grill shutter device according to claim 1 , wherein if the open state of the shutter mechanism is not confirmed even after the electronic control unit controlled the shutter mechanism to open the shutter mechanism in the traveling end state, the electronic control unit controls the shutter mechanism to open the shutter mechanism again.

13. The grill shutter device according to claim 1 , wherein the electronic control unit is configured such that it does not perform the opening operation of the shutter mechanism when confirming the open state of the shutter mechanism.

14. A grill shutter mechanism comprising:

a shutter mechanism adapted to be provided in a grill opening of a vehicle body, wherein the shutter mechanism is operable to be opened and closed to control a flow rate of air flowing into the vehicle body; and

an electronic control unit, which controls opening and closing operations of the shutter mechanism, wherein the electronic control unit is configured to

detect an operation amount of the shutter mechanism by counting pulse signals that are in synchronization with the opening and closing operations of the shutter mechanism,

confirm the open state of the shutter mechanism based on the operation amount of the shutter mechanism when a start switch of a vehicle is turned OFF,

determine whether the pulse signals are normal,

determine that the open state of the shutter mechanism cannot be confirmed when determining that the pulse signals are not normal,

control the shutter mechanism to open the shutter mechanism if the open state of the shutter mechanism is not confirmed, and

refrain from performing the opening operation of the shutter mechanism if the open state of the shutter mechanism is confirmed.