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