Fender Design - Wheel Arch Challenge

Wheel Arch Gap Calculation :-

Aim :

To calculate the wheel arch gap at required points and check whether the car passes the European standard.

Objective :

• Study about the different wheel arch gap standards.
• Draw the lines at the required angle and points for the European standard.
• Measure the distance at each angles and mention given model is pass or fail.

Theory :-

Fender is the American English term for the part of an automobile, motorcycle or other vehicle body that frames a wheel well (the fender underside). Its primary purpose is to prevent sand, mud, rocks, liquids, and other road spray from being thrown into the air by the rotating tire. Fenders are typically rigid and can be damaged by contact with the road surface.

Sticky materials, such as mud, may adhere to the smooth outer tire surface, while smooth loose objects, such as stones, can become temporarily embedded in the tread grooves as the tire rolls over the ground. These materials can be ejected from the surface of the tire at high velocity as the tire imparts kinetic energy to the attached objects. For a vehicle moving forward, the top of the tire is rotating upward and forward, and can throw objects into the air at other vehicles or pedestrians in front of the vehicle.

In British English, the fender is called the wing. (This may refer to either the front or rear fenders. However, in modern unibody vehicles, rear fenders may also be called quarter panels.) The equivalent component of a bicycle or motorcycle, or the "cycle wing" style of wing fitted to vintage cars, or over tires on lorries which is not integral with the bodywork, is called a mudguard in Britain, as it guards other road users – and in the case of a bicycle or motorcycle, the rider as well – from mud, and spray, thrown up by the wheels.

In modern Indian and Sri Lankan English usage, the wing is called a mudguard. However, the term mudguard appears to have been in use in the U.S. at one point. The American author E.B. White, in his October 1940 Harper's essay "Motor Cars", refers to "...mudguards, or 'fenders' as the younger generation calls them.

In the United States, a minor car accident is often called a "fender bender".

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, water 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 deemed usable in that country.

Fender Wheel Arch Regulations :

Japan 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 30degree forward and 50degree rearwards from the central vertical axis of the wheel.

European 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 30degree forward and 50degree rearwards from the central vertical axis of the wheel.

US Regulations :

• Clearance "L" is to be checked at all positions from -100degree to 100degree 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 30degree forward and 50degree rearwards from the central vertical axis of the wheel.

Calculations of wheel Arch area - 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 and the procedure as follows.

From the given part file we need to open in the NX cad and from the part file they give the fender and the wheel. So, now we need to check for the European regulations standard. Now we need to create the Datum plane at the outer most face of the wheel as shown in figure.

Create sketch on the datum plane and then project the points on to the fender so as to measure the 'L' distance.

• 'L' value at SA :-

The value seems to be 9.9490mm which is less than 10mm.

• 'L' distance at SB :-

The value seems to be 10mm which meets the regulations of European Standard.

• 'L' distance at SC :-

'L' distance seems to be 0.113949mm which is opposite side of the wheel arch. Hence it does not satisfy the criteria hence it has failed the regulations.

• 'L' distance at SD :-

'L' distance seems to be 2.8851mm which is opposite side of the wheel arch. Hence it does not satisfy the criteria hence it has failed the regulations.

• 'L' distance at SE :-

'L' distance seems to be 5.9973mm which is opposite side of the wheel arch. Hence it does not satisfy the criteria hence it has failed the regulations.

Calculatons of 'a' Value is as follows :-

'a' value for SC seems to be 43.3599 which overall satisfies the criteria of European Standard.

Section	L(>10mm)	Result
SA-SA	9.9490mm	Fail
SB-SB	10.000mm	Pass
SC-SC	-0.113949mm	Fail
SD-SD	-2.8851mm	Fail
SE-SE	-5.9973mm	Fail

Conclusion :

From the above results we can conclude that the Fender does not pass the European Regulations as the minimum clearance between the fender arch wheel to the outer most wheel is 10 mm and this design does not meet the this minimum clearance so this fender design is fail for the European Regulation standard.

• Negative sign indicates that the wheel arc is behind the wheel
• All the section don't have the CL L value at least 10mm, only SA is seen to have value 10mm
• I have study from the above results, We have conclusion that the fender does not pass the European Regulations, as the Minimum Clearence value of 'L' between the fender wheel arch and wheel for vehicle and Safety is 10 mm and this design does't meet the requirement.