2. Documentation about similar solutions
3. Definition of main parameters
Definition of main parameters
Masses and Centre of gravity
Wheels and Tires
Number of axles
Number of wheels per axle
Static radius of the wheels
Adoption of normal and most difficult driving conditions
4. Drivetrain characteristics
Drivetrain kinematic scheme
5. Determination of gear ratios
Determination of the final drive ratio
Determination of gerbox ratios
6. Vehicle performances
Dynamic factor characteristic
Extras din document
An Off-Road vehicle represents any type of vehicle which can be driven on and off paved or gravel surface. To be able to drive off the pavement, they need some characteristics like raised ground clearance, large tyres, flexible suspension or even tracks.
Main characteristics of an off-road vehicle are low ground pressure, so as not to sink into soft ground, raised ground clearance to not get hung up on obstacles and they use tall and flexible suspension to keep their wheels or tracks on ground so as not to lose traction. The choice of wheels vs tracks is one of cost and suitability. A tracked drivetrain is more expensive to produce and maintain. Any of this choise have benefits and restrictions, tracked drivetrain has greater off-road capability, but slow speed when wheeled trivetrain has higher top speed but less traction capability. Most off-road vehicles are fitted with low gearing. This allows the driver to make the most of the engine’s available power while moving slowly through challenging terrain. An internal combustion engine coupled to a normal gearbox often has an output speed too high. For this, the vehicle either has a very low first gear, or an additional gearbox in line with the first, called a reduction drive. Many off-road vehicles with wheels provide power to all wheels to keep traction on slippery surfaces. This in known as four-wheel drive for typical vehicles and on some, may be designed to be switched between two-wheel drive and four-wheel drive so that the vehicle uses fewer resources when driven on the road.
Documentation about similar solutions
In order to approach the design of a new type of vehicle, taking into account the data imposed by the theme, which specifies certain features related to its destination and performance, it is necessary, in a first stage, to seek as many constructive solutions as possible, already existing, having characteristics similar to those of the requested vehicle.
Common comercial Off-Road Vehicles are classified to be SUV (Sport Utility Vehicles) in many types: Crossover, Mini, Compact, Mid-size, Full-size and Extended-lenght SUV which inlcudes any four-wheel drive pickup trucks like Opel Frontera, Toyota L-450, Nissan Terrano, Citroen Visa, Mitsubishi Pajero, Subaru Forester and others.
Other type of Off-Road Vehicles are ATVs (All-Terain Vechicles), Dirt bikes, Dune Buggies, Rock Crawlers and Sandrails.
For other commercial, military and less common Off-Road Vehicles can be mentioned vechicles used by European militaries and utilities that have used Land-Rover Defenders, Volvo L3314, Mercedes-Bens Unimogs but the military market for Off-Road Vehicles used is large.
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- Dynamics of an Off-Road Vehicle equipped with a 87kw at 4250rpm compression ignition engine.docx
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