Fender Design - Wheel Arch Challenge

FENDER WHEEL ARCH CALCULATION:

AIM:

To Calculate the Wheel Arch gap at required points and check whether the car passes the European standard.

OBJECTIVE:

• To calculate the clearance (L) at sections of SA-SA, SB-SB, SC-SC, SD-SD and SE-SE as per the European Regulations Requirement and tabulate them.
• To measure the wheel guard requirement, the value of ‘a’ from a line 30 degree forward and 50-degree rearward from the central vertical axis of axis of wheel.

WHEEL ARCH:

• It is a curved part of the fender positioned right above the wheel.
• The wheel arch is designed such that it protects both the pedestrian and car cabin from mud, sand, rocks and other road spray.
• Different countries have different wheel arch regulations in place, and the wheel arch design has to comply with them to be allowed to usable in that country.
• For avoiding design alterations of the same vehicle to meet the different regulations in different countries, the maximum values of the concerned regulation parameters are taken into consideration for design purpose.

FENDER WHEEL ARCH REGULATIONS:

Japan wheel arch regulations:

• The clearance ‘L’ for tire, hub, cap and fender is to be measured within area K and create clearance check chart to validate
• The value of L should be greater than 5mm at all positions
• Wheel guard requirement: The value of ‘a’ should be more than 5mm at line 30° forward and 50° rearwards from the central vertical axis of the wheel

European wheel arch regulations:

• The Clearance ‘L’ should be measured at sections SA-SA, SB-SB, SC-SC, SD-SD and SE-SE and create clearance check chart to validate.
• At all the five sections the value of L should be greater than 10mm to satisfy the European Regulations
• Wheel guard requirement: The value of ‘a’ should be more than 5mm at line 30° forward and 50° rearwards from the central vertical axis of the wheel.

US Wheel arch regulations:

• Clearance ‘L’ is to be checked at all positions from -100° to 100° and create clearance check chart to validate.
• The value of L should be greater than 5mm to satisfy the regulations.
• Wheel guard requirement: The value of ‘a’ should be more than 5mm at line 30° forward and 50° rearwards from the central vertical axis of the wheel.

Conditions to meet the European Regulations Requirement:

• The clearance value (L) should be greater than 10mm at all the five sections such as SA-SA, SB-SB, SC-SC, SD-SD and SE-SE to satisfy the European Regulations Requirement.
• The wheel guard requirement value of ‘a’ should be greater than 5mm at a line of 30 degree forward and 50-degree rearward from the central vertical axis of axis of wheel.

CALCULATION OF WHEEL ARCH AREA ACCORDING TO EUROPEAN REGULATIONS:

For calculation of clearance between Wheel Arch and Wheel we have to create a sketch on the outer most face of the wheel. The procedure of which is given below.

• A Datum Plane is created at the outermost face of the wheel.
• A sketch is created on the new datum plane which is created.
• Horizontal line is drawn across the centre of the wheel axis.
• A perpendicular line in 90 degree is drawn from the centre of the wheel axis which is known as SA.
• Two lines of SB and SC are drawn at 30° forward from the SA and 50° rearward of SA respectively.
• A point is created at 150mm vertically above the horizontal line which coincides with the fender edge.
• A line SE is created from the centre axis of the wheel through the point which is created at 150mm.
• A midpoint is created between the SC and SE lines. Then a line SD from centre axis of the wheel is drawn through the midpoint which is created between the SC and SE.

Obtaining clearance value ‘L’ at the required sections:

A clearance distance value of ‘L’ is calculated at the required sections according to the European regulations such as SA-SA, SB-SB, SC-SC, SD-SD, SE-SE, which should be greater than or equal to 10mm.

Clearance value ‘L’ at section SA-SA:

• A clearance value ‘L’ at section SA-SA is 9.94mm.

Clearance value ‘L’ at section SB-SB:

• A clearance value ‘L’ at section SB-SB is 10mm.

Clearance value ‘L’ at section SC-SC:

• A clearance value ‘L’ at section SC-SC is 0.53mm.

Clearance value ‘L’ at section SD-SD:

• A clearance value ‘L’ at section SD-SD is -3.03mm.
• So here, the wheel is somewhat outside from the fender. And that negative distance is 3.03mm.

Clearance value ‘L’ at section SE-SE:

• A clearance value ‘L’ at section SD-SD is -5.98mm.
• Here, the fender is towards the inside from the wheel of about 5.98mm.

MEASURING THE CLEARANCE VALUE ‘a’ FOR THE WHEEL GUARD REQUIREMENT:

The wheel guard requirement value ‘a’ should be greater than 5mm at a line of 30 degree forward and 50-degree rearward line from the central vertical axis of axis of wheel.

Clearance value ‘a’ at 30°-line SB:

• Clearance value ‘a’ at 30°-line SB is 44.7mm.

Clearance value ‘a’ at 30°-line SC:

• Clearance value ‘a’ at 50°-line SC is 37.8mm.

CONCLUSION:

From the above results, we can conclude that the Fender does not pass the European Regulations, as the minimum clearance ‘L’ between the Fender wheel arch and wheel for vehicle should be 10mm and this design does not meet the European Regulation requirements.