Fender Design - Wheel Arch Challenge

What is Wheel arch and wheel arch gap?

The wheel arch is the arch-shaped portion in the fender of the vehicle which houses a wheel, providing room for the proper steering and movement of the wheel taking into consideration pedestrian and vehicle cabin protection and the wheel arch gap is the distance from the wheel top edge to the wheel arch edge.

WHEEL ARCH WHEEL ARCH GAP

Depending on the region/country wheel arch regulations have been made and with respect to that the design parameters are to be constrained so that they can be applied to the market. To avoid design alterations of the same vehicle to meet the different regulations parameters are taken into consideration for design purposes.

Let's discuss some of the regulations

JAPENES REGULATION.

In this regulation, the area of measurement focused on is the least in comparison to other regulations (It is denoted as Area K in the below image). The value of clearance (L) should be greater than 5mm at all positions and the value of Wheel guard requirement (a) should be more than 5mm at line 30 degrees forward and 50 degrees rearwards from the central vertical axis of the wheel for validation.

ie. L = >5mm (40,90,120 degrees)

a = >5mm (at 90+30 and 90-40 degrees)

JAPANESE REGULATION

EUROPEAN REGULATIONS

The area of measurement is almost the same as Japanese regulation but exceeds more from the 0 degrees, which is taken as 150mm above the axis. The value of clearance (L) is measured at the five sections ( SA-SA, SB-SB, SC-SC, SD-SD, and SE-SE) and should be greater than 10mm. The wheel guard requirement is the same as that of Japanese regulation.

ie. L = >10mm (26.88,33.44,40,90,120 degrees)

a = >5mm (at 90+30 and 90-40 degrees)

EUROPEAN REGULATION

US REGULATIONS

In US regulation the entire wheel arc area is measured which can be -10 degrees to 190 degrees. The value of clearance and wheel guard requirements are the same as Japanese regulations greater than 5mm at all positions and more than 5mm at line 30 degrees forward and 50 degrees rearwards from the central vertical axis of the wheel for validation.

ie. L = >10mm (-10 degrees to 190 degrees)

a = >5mm (at 90+30 and 90-40 degrees)

US REGULATION

REGULATION	CLEARANCE (L)	WHEEL GUARD REQ ( a)	MEASUREMENT AREA
JAPAN	>5 mm	>5 mm	40 to 120 degrees
EUROPE	>10 mm	>5 mm	26.88 to 120 degrees
US	>5 mm	>5 mm	-10 to 190 degrees

VALIDATION OF THE GIVEN WHEEL ARCH PART FOR EUROPEAN REGULATION

For validation of the wheel arch, the wheel center axis is to be created. To do so we use a datum plane on the face and sketch the angular sections and by intersecting the section onto the offset wheel and wheel arch profile we get the point. By analyzing the points with a measurement tool we can get the required data for validation.

CONDITION OF EUROPEAN REGULATION

1. Clearance (L) should be greater than 10mm at the five points

2. Wheel guard requirement (a) should be greater than 5mm at 120 and 40 degrees.

The process and measurement done are shown below

DATUM PLANE CREATION ^

SKETCH CREATION ^

CLEARANCE (L) MEASUREMENTS

MEASUREMENT AT SECTION POINT A&a L= 10.000mm (PASS)^

MEASUREMENT AT SECTION POINT B&b L= 9.9490mm (FAIL)^

MEASUREMENT AT SECTION POINT C&c L= 0.1139mm (FAIL)^

MEASUREMENT AT SECTION POINT D&d L= 2.8875mm (FAIL)^

MEASUREMENT AT SECTION POINTS E&e L= 5.9973mm (FAIL)^

SECTION POINTS	A&a	B&b	C&c	D&d	E&e
CLEARANCE (L)	10 mm	9.94 mm	0.11 mm	2.88 mm	5.99 mm
VALIDATION (should be >10mm)	PASS	FAIL	FAIL	FAIL	FAIL

WHEEL GUARD REQUIREMENT (a) MEASUREMENT

MEASUREMENT AT SECTION POINTS A&T1 a = 44.7577 mm (PASS)^

MEASUREMENT AT SECTION POINTS C&T2 a = 38.3599 mm (PASS)^

SECTION POINTS	A&T1	C&T2
WHEEL GUARD REQ (a)	44.75 mm	38.35 mm
VALIDATION (should be >5mm)	PASS	PASS

CONCLUSION

Only at section points A&a, A&T1, and C&T2, the conditions of European regulation were met, Rest all the section point data didn't meet the condition. So in the overall validation, the design is not fit for the European regulation