Movement resistance

Driving resistors are resistors that act against a moving vehicle and consume some of the motor's power.

1. Air resistance

This is caused by the air blowing and flowing around the vehicle. The air resistance corresponds to the force that the vehicle's engine must apply in order for the vehicle to enter the atmosphere. Occurs at any vehicle speed. It is directly proportional to the size of the front surface of the vehicle "S", the coefficient of air resistance "cx" and the square of the speed of movement "V" (no wind). If we are driving with the wind in the back, the relative speed of the vehicle in relation to the air decreases, and thus the air resistance also decreases. The headwind has the opposite effect.

2. Rolling resistance

It is caused by the deformation of the tire and the road, if the road is hard, it is just the deformation of the tire. Rolling resistance causes the tire to roll on the ground and occurs when driving in any of its modes. It is directly proportional to the weight of the vehicle and the rolling resistance coefficient "f". Different tires have different rolling resistance coefficients. Its value varies depending on the design of the tire, its tread, and also depends on the quality of the surface on which we are driving. The rolling resistance coefficient also varies slightly with driving speed. It also depends on the radius of the tire and its inflation.

3. Resistance to lifting

This is the load component of the vehicle that is parallel to the road surface. Thus, uphill resistance is the component of gravity that acts against the direction of travel if the vehicle is ascending, or in the direction of travel if the vehicle is descending - it is moving downhill. This force increases the load on the engine if we go uphill and load the brakes when going downhill. They heat up when braking, which reduces their effectiveness. This is also the reason why vehicles over 3500 kg must be driven downhill in gear and must be equipped with retarders to take the load off the service brakes. Climbing resistance is directly proportional to the weight of the vehicle and the slope of the road.

4. Resistance to acceleration - resistance of inertial masses.

During acceleration, the inertial force acts against the direction of acceleration, which increases with increasing acceleration. Inertial drag occurs each time the vehicle's speed changes. He tries to maintain the state of the car. When the car slows down, it is overcome by the brakes, when accelerating, the car's engine. The resistance of the inertial masses depends on the weight of the vehicle, the amount of acceleration, the gear engaged and the moment of inertia of the wheels and engine masses.