Vehicle Testing on Proving Ground

By - G. Paul Manohar (133705)

Objectiveso Understand the meaning of Proving Ground.o Study the general layout of Proving Ground.o Know various tests carried out there.o Understand the basic principle of each test.

What is a Proving Ground? Proving ground is an area where the performance of an automobile

is put to test.Proving grounds generally spread over hundreds of acres and have

roads and facilities to assess the working of various systems of the automobile.

Mostly, proving grounds are situated far from populated areas.They maintain maximum possible diversity in drive conditions.

Types of Proving Grounds

• Depending on the vehicles being tested, proving grounds can be classified as:• Aeronautical Applications• Military Applications• Automobile Testing• Marine Performance Testing• Aerospace Applications (For test-firing missiles and drones)

Here, we will confine ourselves to Automobile Testing

Types of Proving Grounds for Automobiles

Most of the test-tracks can classified as on of the below: Fast lane tracks: These tracks are specially made for performance testing of automobiles at high speeds.Slow lane tracks: These are generally designed to obtain the performance of vehicle during city driving, low-traction driving, off-road driving (on pavement).Off road tracks: These generally range from second class roads to wild terrains.Custom tracks: These are specially made to impose special conditions for which a vehicle is designed.

It is quite difficult to give an absolute definition for each of the tracks. This is because every track designer has his/her personal views of what a track should be and employs his discretion in bringing out the track. Most general principle adopted is to design the track to suit local conditions and to conform to the National rules.

Fast tracks:

These are often long (7-10 km approx.) and have smooth turns and curves with good enough banking. Testing is generally carried out at about 80-120 kmph depending on the car.

While the vehicle is travelling on these tracks, the following data can be obtained from the automobile.

•Braking performance

•Engine Performance

•Coast Down data

•Dynamic response

•Durability

Some of the braking patches are shown above. The coefficient of friction of track varies based on the material the track is made of.Ex. Low friction Ceramic Tiles - 0.1

Low friction Basalt Tiles - 0.3Dry tarmac - 0.8

Slow tracks:

These may have potholes, pits, speed breakers, water pits, ambient fog, etc., Cars travelling on these tracks travel at about 10-30kmph. Tests on slow tracks yield the following data:•Endurance of body structure•Performance of Suspension at low speeds•Vehicle’s performance in corrosive environment

Off-road tracks:

Here, no road is laid and the terrain may range from mud to hill rocks. Off-road vehicle generally have All-wheel drive with differential locking for better off-road performance. These vehicles are tested for torque, high grade performance, suspension and steering stability.

A normal Proving ground is expected to have all the afore-mentioned types of tracks. In some countries like Sweden, Australia and Norway tracks are built for special conditions.

Sweden - Snow Track

Australia - Mud Track

As mentioned earlier, the configuration of test track heavily relies on the notions of the track-designer. The layout will also change accordingly.

Often, a particular proving ground is chosen for a vehicle depending on the expected performance to avoid failure.

Premium cars and luxury SUVs challenge the toughest tracks to claim better reputation.

Figure shows a general layout of Proven Ground

Various sections:1. 5 mile high speed track2. Mile ride course3. Cobblestone course4. City course5. Belgian Block course6. Flintstone gravel course7. ABS Gravel course8. Limestone Gravel Course9. Offroad course10. Sandwash offroad course with cross country bumps section11. Mud course12. Roug road course with traction bumps13. Potholes course14. Body twist15. Vehicle Dynamics Facility

16. Paved hill Climb Event

17. Steering Event Course

18. Splash Troughs

19. Rain Test

20. a Headquarters/Office Buildings,

Workshops 1-4, Inspection Station,

Security Entrance Gate, Weather Station

b Workshop 5 c High-speed Track Control Center & Idle Box

d Idle Box at 2-Mile Ride Course

e Work station

f Fuel Stations

g Conference Building

(Source- Mercedes Benz Tech)

• Data Acquisition and Communication:

Sensors are attached to various critical portions of the automobile. Data from sensors in stored in flash memory. A typical flash memory device can store upto 2GB test data. This data may be communicated to analyser simultaneously or at a later stage.

The test data is then used to analyse and comment on vehicle’s performance.• The Data Acquisition System (DAS) is a standalone system and stores

the data without ever communicating with the electronic components of the vehicle.• The DAS system some times contains interface software like WIN.

Sensors used are:• For Aerodynamic forces and crash forces - Capacitive and resistive

pressure gauges attached externally on bonnet and tail.• For dynamic loads – Accelerometers and Vibrometers at suspension

linkage (or) wheel hub.• For tyre loads – Pressure sensors in the tyre.• For structural loads – Strain gauges on body and frame.• For vehicle statistics – On board sensors.

Facilities at ARAI

References• Catalogue of Australian Automotive Research Centre

• Catalogue of ARAI, Pune

• Catalogue of MIRA

• MBTech catalogue