Optical axis adjustment device

An optical axis adjustment device for a headlamp unit to be mounted in a vehicle is configured to adjust an optical axis of the headlamp unit. the optical axis adjustment device includes an engine temperature acquirer, a displacement amount calculator, an operation information acquirer, and an optical axis adjuster. The engine temperature is configured to acquirer acquire a temperature in an engine compartment of the vehicle. The displacement amount calculator is configured to calculate a displacement amount of the optical axis on a basis of the temperature. The operation information acquirer is configured to acquire operation information indicating an operation status of a cooling device for the engine. The optical axis adjuster is configured to adjust the optical axis of the headlamp unit on a basis of the displacement amount and the operation information.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority from Japanese Patent Application No. 2021-159758 filed on Sep. 29, 2021, the entire contents of which are hereby incorporated by reference.

BACKGROUND

The disclosure relates to an optical axis adjustment device configured to adjust an optical axis of a vehicle headlamp to be installed in a vehicle.

A vehicle headlamp is adjusted so that an optical axis thereof is positioned within a range defined by laws and regulations. A known example of an optical axis adjustment device that adjusts an optical axis of a vehicle headlamp is an automatic leveling device. The automatic leveling device is configured to adjust, when an angle of a vehicle body in a front-rear direction is inclined with respect to a horizontal direction, the optical axis of the vehicle headlamp according to the inclination angle (Japanese Unexamined Patent Application Publication (JP-A) No. 2009-234456).

SUMMARY

An aspect of the disclosure provides an optical axis adjustment device for a headlamp unit to be mounted in a vehicle. The optical axis adjustment device is configured to adjust an optical axis of the headlamp unit. The optical axis adjustment device includes an engine temperature acquirer, a displacement amount calculator, an operation information acquirer, and an optical axis adjuster. The engine temperature acquirer is configured to acquire a temperature in an engine compartment of the vehicle. The displacement amount calculator is configured to calculate a displacement amount of the optical axis on a basis of the temperature. The operation information acquirer is configured to acquire operation information indicating an operation status of a cooling device for the engine. The optical axis adjuster is configured to adjust the optical axis of the headlamp unit on a basis of the displacement amount and the operation information.

An aspect of the disclosure provides an optical axis adjustment device for a headlamp unit to be mounted in a vehicle. The optical axis adjustment device is configured to adjust an optical axis of the headlamp unit. The optical axis adjustment device includes an engine temperature acquisition circuit and circuitry. The circuitry is configured to acquire a temperature in an engine compartment of the vehicle. The circuitry is configured to calculate a displacement amount of the optical axis on a basis of the temperature. The circuitry is configured to acquire operation information indicating an operation status of a cooling device for the engine. The circuitry is configured to adjust the optical axis of the headlamp unit on a basis of the displacement amount and the operation information.

DETAILED DESCRIPTION

During vehicle travel, the ambient or internal temperature of a vehicle headlamp changes depending on the surrounding environment and travel conditions of the vehicle, and such a temperature change may cause a shift in the optical axis of the vehicle headlamp. In one example, the temperature change may cause a housing of the vehicle headlamp to thermally expand, and the vehicle headlamp itself may shift with respect to a vehicle body. In another example, the temperature change may cause a light source unit accommodated inside the housing of the vehicle headlamp to thermally expand, and the light source unit may shift with respect to the housing. Such a shift may cause the optical axis of the vehicle headlamp to deviate from a predetermined range.

However, the automatic leveling device of JP-A No. 2009-234456 described above is not designed to adjust a shift in the optical axis caused by a temperature change.

In recent years, as light sources (light-emitting diodes (LEDs)) used in vehicle headlamps have become higher in definition and the use of high-performance vehicle headlamps, such as adaptive driving beam (ADB) headlamps, has become widespread, higher-precision optical axis adjustment has become desirable.

This disclosure addresses such a situation. In other words, it is desirable to calculate and adjust a shift in an optical axis caused by temperature changes around a vehicle headlamp, and the like.

As illustrated inFIG.1, an optical axis adjustment device to be mounted in a vehicle according to the embodiment of the disclosure may serve as part of a vehicle control system1and is provided in a vehicle100. The vehicle control system1includes various electronic devices used for the travel of the vehicle100, as well as in-vehicle electronic control units (ECUs) configured to control these electronic devices. Each electronic device, each in-vehicle ECU, and the like are communicably coupled to one another by an in-vehicle network3, such as a controller area network (CAN) or a local interconnect network (LIN). Further, each electronic device, each in-vehicle ECU, and the like are coupled to a central gateway (CGW)4serving as a relay device, and thus constitute the vehicle control system1.

Each in-vehicle ECU can include, for example, a processor such as a central processing unit (CPU) or a micro processing unit (MPU), electrical circuitry, and a storage element such as a random access memory (RAM) or a read only memory (ROM). Further, operations executed by the in-vehicle ECUs can be fully or partially realized by hardware such as an application specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or a graphics processing unit (GPU).

In the following description, detailed descriptions and illustrations of electronic devices and the like not directly related to the optical axis adjustment device (an optical axis adjustment ECU11) according to the present embodiment will be omitted.

As illustrated inFIG.1, the vehicle control system1includes, as the in-vehicle ECUs, the optical axis adjustment ECU11, an engine ECU21, a brake ECU31, a steering ECU41, an air conditioning ECU51, and a wiper ECU61. Each in-vehicle ECU is coupled to an electronic device controlled by the in-vehicle ECU, and controls operation of the coupled electronic device on the basis of information (data) acquired from the in-vehicle network3. Further, each in-vehicle ECU outputs information indicating a status, such as an operating status of the coupled electronic device, to the in-vehicle network3.

The optical axis adjustment ECU11is coupled to a headlamp unit13provided in a front portion of the vehicle and a driver12configured to drive the headlamp unit13. Further, the optical axis adjustment ECU11functions as an optical axis adjustment device configured to adjust an optical axis of the headlamp unit13. Details of the optical axis adjustment ECU11will be described below.

The engine ECU21, the brake ECU31, and the steering ECU41are respectively coupled to an engine, brakes, and a steering wheel. The engine ECU21, the brake ECU31, and the steering ECU41control the travel of the vehicle on the basis of the information acquired from the in-vehicle network3.

In particular, the engine ECU21is coupled to an oil temperature sensor22, a coolant temperature sensor23, an engine rotation sensor24, and a cooling device25. The oil temperature sensor22detects an oil temperature of the engine during travel and outputs the oil temperature to the engine ECU21. The coolant temperature sensor23detects a coolant temperature of the engine during travel and outputs the coolant temperature to the engine ECU21. The engine rotation sensor24detects a rotation speed of the engine from an ignition pulse, for example, and outputs the rotation speed to the engine ECU21. The engine ECU21is coupled to the cooling device25, and the cooling device25outputs an operation state of the cooling device25to the engine ECU21. In the present embodiment, the cooling device25is, for example, a radiator fan that cools the engine, an active grill shutter that reduces travel resistance, or the like. Further, the cooling device25is a device that, when operated, brings about a temperature change in the engine compartment, even if the main purpose thereof is not to cool the engine.

In addition, the engine ECU21, the brake ECU31, and the steering ECU41acquire, from electronic devices respectively coupled thereto, status information (for example, information related to torque, accelerator pedal position, vehicle travel speed and travel time, fuel consumption, depressed amount of foot brake, on/off state of parking brake, or steering angle and steering amount of steering wheel) indicating a status of the electronic device, and output the acquired information to the in-vehicle network3.

The air conditioning ECU51is coupled to an outside temperature sensor52attached to a vehicle exterior. The air conditioning ECU51controls an air conditioning unit (not illustrated) on the basis of an outside temperature acquired from the outside temperature sensor52and information acquired from the in-vehicle network3. That is, while referencing the outside temperature acquired from the outside temperature sensor52, the air conditioning ECU51controls the air conditioning unit so that the temperature inside the vehicle is a desired temperature set by a user.

The wiper ECU61is, for example, coupled to a raindrop sensor62that detects rainfall by a raindrop amount deposited on a windshield, and operates a wiper at predetermined intervals according to the raindrop amount acquired from the raindrop sensor62. Alternatively, the wiper ECU61operates the wiper according to information based on an operation by an occupant of the vehicle. The information is acquired via the in-vehicle network3.

Optical Axis Adjustment Device

In the following, the optical axis adjustment ECU11serving as the optical axis adjustment device will be described. The optical axis adjustment ECU11controls the driver12with reference to the information acquired from each in-vehicle ECU described above via the in-vehicle network3. On the basis of such control, the optical axis adjustment ECU11adjusts an optical axis of light emitted from the headlamp unit13, positioning the optical axis within a predetermined range. In one embodiment, the ECU11may serve as an “optical axis adjustment device”.

As illustrated inFIG.2, the optical axis adjustment ECU11includes a CPU111, a ROM112, and a RAM113.

The CPU111executes various processes on the basis of a program stored in the ROM112. In the present embodiment, the CPU111loads the program stored in the ROM112into a memory such as the RAM113, and executes the program. As a result, the CPU111may serve as an engine temperature acquirer114, a displacement amount calculator115, an operation information acquirer116, and an optical axis adjuster117illustrated inFIG.2. In the following, the engine temperature acquirer114, the displacement amount calculator115, the operation information acquirer116, and the optical axis adjuster117will be described.

The engine temperature acquirer114acquires, via the engine ECU21and the in-vehicle network3, the oil temperature of the engine detected by the oil temperature sensor22or the coolant temperature of the engine detected by the coolant temperature sensor23as the temperature in the engine compartment. The engine temperature acquirer114may predict the temperature in the engine compartment on the basis of the engine rotation speed acquired from the engine rotation sensor24.

The displacement amount calculator115calculates a displacement amount (shift amount) of the optical axis of the headlamp unit13on the basis of the temperature in the engine compartment acquired by the engine temperature acquirer114. For example, a formula for calculating the displacement amount according to the temperature in the engine compartment, or a table associating the temperature in the engine compartment and the displacement amount is stored in the ROM112or the like in advance. The displacement amount calculator115calculates the displacement amount on the basis of this formula or table. In some embodiments, the formula or the table is acquired in advance for each vehicle by simulation or the like.

The operation information acquirer116acquires operation information indicating an operation status of the cooling device25. The cooling device25is a device that, when operated, brings about a temperature change in the engine compartment. Examples of the cooling device25include a radiator fan that cools the engine and an active grill shutter that reduces travel resistance.

Operation of the cooling device25makes it difficult to predict the temperature around the headlamp unit13from only the engine compartment temperature estimated from the temperature acquired from the oil temperature sensor22or the coolant temperature sensor23. Further, operation of the cooling device25makes such prediction difficult from only the engine compartment temperature predicted from the engine rotation speed acquired from the engine rotation sensor24. In such a case, the operation status of the cooling device25is to be taken into account, and thus the operation information acquirer116acquires the operation information indicating the operation state of the cooling device25.

For example, when the cooling device25is a radiator fan, the operation information includes a rotation frequency, a rotation speed, and an operation time of the radiator fan. When the cooling device25is an active grill shutter, the operation information includes an opening degree of the active grill shutter, and a duration for which an open state is maintained. The acquired operation information is output to the optical axis adjuster117.

The optical axis adjuster117determines the adjustment amount of the headlamp unit13on the basis of the displacement amount calculated by the displacement amount calculator115and outputs a drive signal indicating the adjustment amount to the driver12.

Further, in a case where the operation information acquirer116has acquired the operation information, the optical axis adjuster117corrects the displacement amount calculated by the displacement amount calculator115. The optical axis adjuster117then determines the adjustment amount of the headlamp unit13according to the corrected displacement amount, and outputs a drive signal indicating the adjustment amount to the driver12.

Further, in a case where the operation information includes the operation time of the cooling device25and the operation time indicates that a predetermined time has elapsed from a start of operation, the optical axis adjuster117does not output a drive signal to the driver12. Thus, the optical axis of the headlamp unit13is not adjusted. This is in consideration of the fact that the cooling device25has operated for a certain time or longer, sufficiently cooling the area around the headlamp unit13and eliminating the need for optical axis adjustment. Accordingly, in some embodiments, as the predetermined time, a duration for which the area around the headlamp unit13is sufficiently cooled is predetermined.

In addition, in a case where the operation information indicates that the cooling device25is in operation, the optical axis adjuster117does not output a drive signal to the driver12, and thus the optical axis of the headlamp unit13is not adjusted. This is in consideration of the fact that, in a case where the cooling device25is operating, the degree of optical axis adjustment and the necessity of optical axis adjustment change depending on how long the operation state subsequently continues.

Headlamp Unit

Next, the headlamp unit13subject to optical axis adjustment by the optical axis adjustment ECU11will now be described with reference toFIG.3toFIG.5.

Headlamp units13are typically provided as a pair on a left side and a right side of the front portion of the vehicle, but one headlamp unit13is illustrated as a representative example inFIG.3toFIG.5. As illustrated inFIG.3toFIG.5, the headlamp unit13includes a light source (not illustrated), a reflector, and a lens in a housing, for example. The reflector directs light emitted from the light source to an area in front of the vehicle, and the lens distributes the light emitted from the light source across a predetermined range.

The headlamp unit13is fixed to a bracket14and attached to a vehicle body80via the bracket14. The bracket14is attached to the vehicle body80by a ball joint141and a horizontal adjustment aiming screw142provided in an upper area of the bracket14. Further, the bracket14is attached to the vehicle body80by a vertical adjustment aiming screw144provided in a lower area of the bracket14with a retainer143interposed therebetween.

The ball joint141is attached to the bracket14so that a ball141A at one end serves as a swing center (fulcrum) of the bracket14, and a screw thread141B at the other end is attached to the vehicle body80.

The vertical adjustment aiming screw144is attached at one end to the bracket14with the retainer143interposed therebetween and at the other end to a vertical aiming adjustment gear146of a leveling unit145on the vehicle body80side.

As the vertical adjustment aiming screw144and the retainer143move in a vehicle front-rear direction, the headlamp unit13is thus vertically tiltably supported together with the bracket14with respect to the vehicle body80. At this time, the ball141A at the one end of the ball joint141serves as the fulcrum.

That is, the vertical adjustment aiming screw144is rotated, moving the retainer143in the vehicle front-rear direction. Further, as the retainer143moves, the lower portion of the bracket14also moves in the vehicle front-rear direction. As a result, the headlamp unit13rotates about the ball141A of the ball joint141and then tilts.

When the optical axis of the headlamp unit13is adjusted, the adjustment can be made manually by an operator or automatically by the optical axis adjustment ECU11.

In the case where an operator performs manual adjustment and rotates the vertical adjustment aiming screw144with a screwdriver, the retainer143moves in the vehicle front-rear direction at the screw thread of the vertical adjustment aiming screw144. As the retainer143moves, the lower portion of the bracket14also moves in the vehicle front-rear direction. As a result, the headlamp unit13rotates together with the bracket14about the ball141A of the ball joint141and then tilts.

In the case of automatic adjustment by the optical axis adjustment ECU11, the driver12(motor, for example) included in the leveling unit145is driven to rotate the vertical adjustment aiming screw144together with the vertical aiming adjustment gear146. The driver12rotates the vertical adjustment aiming screw144so that the vertical adjustment aiming screw144moves in the vehicle front-rear direction and, as the vertical adjustment aiming screw144moves, the retainer143also moves in the vehicle front-rear direction. As a result, the headlamp unit13rotates together with the bracket14about the ball141A of the ball joint141and then tilts.

The optical axis adjustment ECU11according to the present embodiment adjusts the optical axis of the headlamp unit13thus configured as follows.

The headlamp unit13, being attached near the engine of the vehicle body80, is affected by temperature changes in the engine compartment during travel and is thus susceptible to thermal expansion or the like. Therefore, in the optical axis adjustment ECU11, the engine temperature acquirer114acquires the oil temperature of the engine detected by the oil temperature sensor22or the coolant temperature of the engine detected by the coolant temperature sensor23as the temperature in the engine compartment. The optical axis adjustment ECU11then uses this temperature to estimate the temperature around the headlamp unit13near the engine.

The displacement amount calculator115calculates the displacement amount of the optical axis according to the acquired temperature in the engine compartment from the formula or the like stored in the ROM112. The displacement amount calculator115then outputs the calculated displacement amount to the optical axis adjuster117.

The operation information acquirer116outputs the operation information of the cooling device25acquired from the cooling device25to the optical axis adjuster117.

The optical axis adjuster117calculates the adjustment amount of the headlamp unit13on the basis of the displacement amount calculated by the displacement amount calculator115and outputs a drive signal indicating the adjustment amount to the driver12.

Note that, in a case where the operation information exists at this time, the displacement amount is corrected according to the operation information and the adjustment amount of the headlamp unit13based on the corrected displacement amount is calculated. Then, the optical axis adjuster117outputs a drive signal indicating the adjustment amount to the driver12.

Further, in a case where the operation information indicates that the cooling device25has operated for the predetermined time or longer, is currently in operation, or the like, the optical axis adjuster117does not output a drive signal to the driver12. Thus, the optical axis is not adjusted.

Note that, the optical axis adjuster117may correct the displacement amount on the basis of the outside temperature acquired from the outside temperature sensor52or the rainfall amount acquired from the raindrop sensor62, as necessary.

The driver12rotates the vertical adjustment aiming screw144on the basis of the drive signal from the optical axis adjuster117to move the vertical adjustment aiming screw144by the adjustment amount in the front-rear direction relative to the vehicle body80.

As the vertical adjustment aiming screw144moves, the retainer143also moves in the front-rear direction of the vehicle body80by the adjustment amount calculated by the optical axis adjuster117. With this movement, the bracket14rotates about the ball141A and then tilts. As a result, the headlamp unit13supported by the bracket14can vertically tilt with respect to the vehicle body80, and the position of the optical axis can be adjusted according to the displacement amount of the optical axis calculated by the displacement amount calculator115.

Thus, according to the present embodiment, the temperature in the engine compartment is estimated and the displacement (shift) of the optical axis of the headlamp unit13based on the temperature rise is predicted, taking into account temperature changes caused by the cooling device25provided inside the vehicle. This makes it possible to calculate a shift of the optical axis caused by a temperature change around the vehicle headlamp in advance or in real time and adjust the shift with high precision.

Embodiments of the disclosure have been described in detail with reference to the drawings, but exemplary configurations thereof are not limited to these embodiments. Rather, design variations and the like within a range that does not deviate from the spirit and intent of the disclosure are also included in the disclosure. Moreover, insofar as there are no particular contradictions or problems in purposes, configurations, or the like, the techniques of the various embodiments described above may be used in combination.

With the optical axis adjustment device of the embodiment of the disclosure, a shift in an optical axis caused by a temperature change around a vehicle headlamp can be calculated and corrected or adjusted with high precision.