JPH064354U - Heater relay malfunction prevention device in heater energization control device - Google Patents

Abstract

(57) [Abstract] [Purpose] It is possible to prevent burnout of the heater relay and deterioration of the battery even if the control device that controls the energization of the heater relay that energizes the air heater fails while the heater relay is energized. [Constitution] When the controller 3 energizes the heater coil 2B of the heater relay 2 which energizes the air heater 1, when the output voltage of the controller 3 exceeds a predetermined value for a predetermined time or longer, the alarm device 12 turns off the transistor 13. To forcibly stop energization of the heater coil 2B.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a heater energization control device that energizes an air heater that heats intake air via a heater relay, and relates to a device that prevents malfunction of the heater relay.

[0002]

[Prior art]

 A conventional heater energization control device is shown in FIG. 2 (see Japanese Utility Model Publication No. 62-18695). That is, it is connected to the power source through the relay contact 2A of the normally open heater relay 2 of the air heater 1 installed in the intake passage of the engine, and the relay coil 2B of the heater relay 2 is connected to the output terminal of the controller 3. There is.

Then, the control device 3 energizes the relay coil 2B for a predetermined time at the time of starting or the like to close the relay contact 2A, and energizes the air heater 1 from the power source for a predetermined time to heat intake air.

[0004]

[Problems to be solved by the device]

 However, if a heater energization element (for example, a transistor) in the control device 3 fails while the relay coil 2B is energized (ON state), the relay coil 2B is continuously energized, and the heater relay 2 is burned. There is a problem that it causes the deterioration of the battery.

The present invention has been made in view of the above situation, and prevents burnout of the heater relay and deterioration of the battery when the heater relay is continuously energized due to a failure in the control device. It can be so.

[0006]

[Means for Solving the Problems]

 For this reason, the present invention provides a switching means that energizes the air heater that heats the intake air through a relay contact to stop energizing the heater coil of the heater relay, and an output that detects the output voltage of the control device that energizes the air heater. Voltage detection means and energization stopping means for forcibly stopping energization to the relay coil by turning off the switching means when the detected output voltage exceeds a predetermined value for a predetermined time or longer. I did it.

[0007]

[Action]

 Then, when the output voltage of the control device exceeds a predetermined value for a predetermined time, it is determined that a failure has occurred in the control device, and the switching means is forcibly stopped from energizing the relay coil.

[0008]

【Example】

 An embodiment of the present invention will be described below with reference to FIG. The same elements as those in the conventional example are designated by the same reference numerals as those in FIG. In the figure, the output voltage of the control device 3 is applied to the input terminal of the alarm device 12 via the diode 11, and the output terminal of the alarm device 12 is connected to the relay coil 2B of the heater relay 2. Here, in the alarm device 12, the input terminal and the output terminal are connected by a transistor 13 as a switching means. The output voltage of the control device 3 is applied to the voltage detection terminal A of the alarm device 12. Further, the alarm lamp 14 is adapted to be energized by the alarm device 12.

The alarm device 12 outputs an alarm signal when the output voltage of the control device 3 exceeds a predetermined value for a predetermined time (for example, 10 minutes, which corresponds to the energization time from the control device 3 to the heater relay 2B). Determines that a failure has occurred in the control device 3, forcibly turns off the transistor 13 to stop energization of the relay coil 2B, and turns on the alarm lamp 14. Therefore, the alarm device 12 constitutes an output voltage detecting means and an energization stopping means.

According to such a configuration, even if the controller 3 has a failure and the relay coil 2B is continuously energized, the transistor 13 forcibly stops the energization of the relay coil 2B after a predetermined time has elapsed. Therefore, it is possible to prevent the relay coil 2B from being energized for an excessive period of time, so that it is possible to prevent the heater relay 2 from burning and the battery from deteriorating.

The transistor may be arranged on the ground side of the relay coil 2B. Further, the alarm device 12 may be forcibly built in the control device 3.

[0012]

[Effect of device]

 As described above, the present invention forcibly stops the energization of the heater relay when the output voltage of the controller for controlling the energization of the heater relay exceeds a predetermined value for a predetermined time or longer. It is possible to prevent burnout of the battery and deterioration of the battery.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a configuration diagram showing a conventional example of a heater energization control device.

[Explanation of symbols]

 1 Air heater 2 Heater relay 2A Relay contact 2B Relay coil 3 Controller 12 Alarm device 13 Transistor

Claims (1)

[Scope of utility model registration request] 1. A heater energization controller for connecting an air heater for heating intake air to a power source via a relay contact of a normally open heater relay and energizing a relay coil of the heater relay from a controller to energize the air heater. In, switching means for stopping energization to the heater coil, output voltage detection means for detecting an output voltage of the control device, and the switching means when the detected output voltage exceeds a predetermined value for a predetermined time or more. A heater relay malfunction prevention device in a heater energization control device, comprising: an energization stopping means for turning off the switch to forcibly stop energization of the relay coil.