Shows how to calculate the power required to move a vehicle - with some rules of thumb for a modern heavy truck.

1. 1. Propulsion power, constant speed at plain level
• Air resistance
• Rolling resistance tire-ground
• Powertrain losses
Rough rules of thumb for 40t truck:
• 85 km/h (53 mph)  100kW
• 90 km/h (56 mph)  120kW
(20% more power for 6% more speed!)
Example
power requirement

2. 1. Propulsion power, constant speed at plain level
• Air resistance
• Rolling resistance tire-ground
• Powertrain losses
Example
power requirement
Rough rules of thumb for 40t truck:
• 85 km/h (53 mph)  100kW
• 90 km/h (56 mph)  120kW
…for 20t truck:
 80kW
 90kW
(Only 25% less power for >50% less freight!)
20t
40t
This is also one reason why it is more efficient with heavier loads.

3. 2. Propulsion power, constant speed uphill
• Inclination
• Air resistance
• Rolling resistance tire-ground
• Powertrain losses
Rough rule of thumb for driving at 90 km/h (56 mph)
with 40t truck:
•  120kW additional power per 1% inclination
power requirement
Example
120 kW
D  120 kW
D  120 kW
D  120 kW
D  120 kW
with 20t truck:
•  60kW additional power per 1% inclination