the main sources of energy loss on a vehicle

[dmcmixmaster]

I am doing a physics project on the main sources of energy loss on vehicles. For example on a car, lorry, bicycle. Their energy losses due to aerodynamic drag, brakes, and other similar things

[Adam43]

Just off the top of my head I would throw in friction. This includes the friction of the tyres on the road and also the actual car's mechanical moving parts.

When I did my A-levels I did a project using a model of a Porsche 956! I ran it down a track and calculated how far it would jump off the end of a ramp. It was quite easy to calculate it's theoretical speed using the gravitational potential gained and converting this into kinetic energy.

I crudely calculated the friction (road + mechanical) by placing the car on a track and tilting it until the gravitational force component overcame the frictional force. Of course this is stationery friction rather than moving friction.

Ways of reducing energy loss (and hence improve performance and fuel efficiency) include reducing the car's drag coefficient and also improving the efficiency of the tyres (both in design and keeping them at the correct pressure!)

Your final example of brakes is slightly different to the others. It is good to reduce most other energy losses, but it is good to increase the brakes energy loss efficiency!

[KC]

I would agree with AdamAshmore on this. Frictional losses on the internal portions of the engine are still quite high even by todays standards. On F1 cars the aerodynamicist spends huge portions of the teasm budget exploring ways to increase downforce without increase aerodynamic drag, this drag is also a major loss.

[Arneal]

According to the first link listed in the Rotating Liner Engine thread, data from the US Department of Energy shows piston ring friction accounts for 1% of all energy usage in the USA.

[bobdar]

I would guess that the greatest energy loss is tied to the inherent inefficiency of the internal combustion engine. But for objects in motion, isn't it a sliding scale, with friction dominating at low speeds and aerodynamic losses dominating at higher speeds??