1. SCOPE

This SAE standard provides test procedures, performance requirements, design guidelines and installation guidelines for front fog lamps.

2. DEFINITIONS

2.1 FRONT FOG LAMP

A lighting device designed to provide illumination forward of the vehicle under conditions of fog, rain, snow, or dust.

2.2 GRADIENT

A measure of the change in light level over a change in location within the beam. It is an objective means to measure cutoff sharpness and determine cutoff location.

2.3 CUTOFF

A generally horizontal, visual/optical aiming cue in the beam that marks a separation between areas of higher and lower luminance.

2.4 CUTOFF LINE

The line where the maximum vertical photometric gradient is located.

2.5 ASYMMETRICAL LAMPS

Specifically designed lamps intended to be used together on a vehicle having beam patterns that are not symmetrical with respect to the vertical axis through H-V.

2.6 SYMMETRICALLY OPPOSITE LAMPS

Lamps with beam patterns that are mirror images of each other with respect to the vertical axis through H-V.

2.7 HARMONIZED FRONT FOG LAMP

A lamp for use with or without headlamps providing illumination forward of the vehicle under adverse weather conditions designed to harmonize with international front fog lamp requirements.

3. TESTS

3.1 Test Voltage

The test voltage shall be the design voltage ±0.1 Vrms measured at the terminals of the lamp under test unless otherwise specified.

3.2 The following test procedures of SAE J575 apply to this document; however, front fog lamps designed for universal mounting applications or for vehicles having an overall width greater than 2032 mm shall be tested according to test procedures of SAE J2139

3.2.1 Vibration Test

3.2.2 Moisture Test

3.2.3 Dust Test

3.2.4 Corrosion Test

3.2.5 Photometry Test

The lamp shall be mounted on a test fixture, which simulates the vehicle mounting system and any optically significant surrounding structures (e.g., grille, fascia, etc.) in its design operating position and orientation, at a distance of at least    10 m from the photometer.

Light sources used for testing shall meet the requirements of SAE J575. For lamps requiring incandescent bulbs,  accurate rated bulbs operated at their rated luminous flux based on a design voltage of 13.2 volts shall be used. Alternatively, an accurate rated incandescent bulb operated at its rated luminous flux based on a design voltage of 12.8 volts can be used for testing provided that the photometric candela measurements are scaled by a factor of 1.10.

The optical axis of the front fog lamp to be tested shall be centered horizontally on the photometer axis with maximum gradient positioned as determined in Section 5.2.5.1.

3.2.5.1 Gradient Measurement Procedure

Conduct a vertical scan of the lamp beam pattern along the V-V line and at 1 degree right and 1 degree left of the V-V line over a sufficient vertical distance to locate the maximum gradient and determine the shape of the gradient curve. The gradient Glog should be calculated using the mathematical expression: Glog = log10 I(a) – log10 I(a+0.1). Where I is the measured candela value and a is the vertical angular position in degrees.  Plot the results Glog vs. a.

3.2.5.2 Gradient Position in the Beam Pattern

The lamp aim shall be adjusted until the vertical angular position at which the maximum gradient measured along the V-V line is located at 0.75 degree down for a front fog lamp designed to conform to the requirements of photometry Figure 1 of this document or 1 degree down for a front fog lamp designed to conform to the requirements of photometry Figure 2 of this document. The front fog lamp shall then be tested photometrically per SAE J575.

3.2.5.3 If the front fog lamp is combined with a headlamp such that it cannot be aimed separately from the headlamp, the headlamp shall be aimed correctly and the front fog lamp shall then be photometered per SAE J575.

3.2.6 Impact Test

3.2.7 Chemical Resistance Test

3.2.8 Abrasion Test of Plastic Headlamp Lens Material

3.2.9 Thermal Cycle Test

3.2.10 Humidity Test

3.2.11 Internal Heat Test

3.3 The following test procedures of SAE J1383 as specified for headlamps apply to this document:

3.3.1 Aiming Adjustment Test

3.3.2 Color Test

SAE J578 applies for this document.

3.4  Plastic Materials

Plastic materials used in optical parts shall be tested in accordance with the procedures in SAE J576.

3.5 Sealed Beam Unit Tests

Sealed beam units designed for use as front fog lamps are not subject to moisture, dust, and corrosion tests.

4. REQUIREMENTS

4.1 Test Voltage

All performance requirements shall be met at the design voltage as measured at the terminals of the front fog lamp unless otherwise specified.

4.2 SAE J575 Requirements or SAE J2139 Requirements

A device, when tested in accordance with the test procedures specified in Section 5.2, shall meet the following requirements of SAE J575 or SAE J2139, whichever is applicable:

4.2.1 Vibration

4.2.2 Moisture

4.2.3 Dust

4.2.4 Corrosion

4.2.5 Photometry

4.2.5.1 Gradient - The lamp shall be designed to conform to the following requirements:

4.2.5.1.1 The maximum vertical gradient Glog along the V-V line as measured in Section 5.2.5.1 shall be ³ 0.08.

4.2.5.1.2  The graphical plot of Glog vs. a in log10 units shall demonstrate a well defined single peak.

4.2.5.1.3  The cutoff line shall be essentially flat from 2.5L to 2.5R. The vertical location of the highest gradient at the ends of the minimum width shall be within ±0.2° of the vertical location of the maximum gradient measured at V-V.

4.2.5.2  Light Distribution for Front Fog Lamp

The lamp shall be designed to conform to the light intensity distribution (candela) values as shown in Figure 1 when  tested in accordance with section 5.2.5. If the front fog lamp does not pass the photometric requirements of Figure 1, it may be re-aimed vertically, provided the location of the maximum gradient falls within the range of 0.5 degree down to 1.0 degree down.

4.2.5.2.1 Asymmetrical Lamps

Sum the left and right hand lamp test point 3D/15L light intensities and the left and right hand lamp test point 3D/15R light intensities. The sum of the recorded candela values at 3D/15L and the sum of the recorded candela values at 3D/15R shall each equal or exceed twice the requirement for Point 7.

4.2.5.2.2 Symmetrically Opposite Lamps

Sum the test points 3D/15L and 3D/15R light intensities for a single lamp. The sum of the recorded candela values shall equal or exceed twice the requirement for Point 7.

4.2.5.3 Light Distribution for Harmonized Front Fog Lamp

The lamp shall be designed to conform to the light intensity distribution (candela) values as shown in Figure 2 when  tested in accordance with Section 5.2.5. If the front fog lamp does not pass the photometric requirements of Figure 2, it may be re-aimed vertically, provided the location of the maximum gradient falls within the range of 0.75 degree down to

1.25 degree down.

4.2.5.3.1 Asymmetrical Lamps

Sum the left and right hand lamp’s 22L maximum light intensities and the left and right hand lamp’s 22R maximum light intensities.  The sum of the recorded candela values at 22L and the sum of the recorded candela values at 22R shall  each equal or exceed twice the requirement for Line 8L. Sum the left and right hand lamp’s 35L maximum light intensities and the left and right hand lamp’s 35R maximum light intensities. The sum of the recorded candela values at 35L and the sum of the recorded candela values at 35R shall each equal or exceed twice the requirement for Line 9L.

4.2.5.3.2 Symmetrically Opposite Lamps

Sum the 22L and 22R maximum light intensities for a single lamp and sum the 35L and 35R maximum light intensities for a single lamp. The sum of the recorded candela values at 22 degrees shall equal or exceed twice the requirement for  Line 8L.  The sum of the recorded candela values at 35 degrees shall equal or exceed twice the requirement for Line 9L.

4.2.6 Impact Test

4.2.7 Chemical Resistance Test

4.2.8 Abrasion Test of Plastic Headlamp Lens Material

4.2.9 Thermal Cycle Test

4.2.10 Humidity Test

4.2.11 Internal Heat Test

4.3  SAE J1383 Performance Requirements

A device, when tested in accordance with the test procedures specified in Section 5.3, shall meet the following requirements of SAE J1383:

4.3.1 Aiming Adjustment Test

4.4 Color

The color of the light from a front fog lamp shall be white or selective yellow within the limits specified in SAE J578.

4.5 Plastic Materials

The plastic materials used in optical parts shall meet the material performance requirements as listed in SAE J576.