|
It works with engine because engines have excess power
I have been seriously looking at this topic - using engines to go up steep hills (pulse) and then pedal power only to go down long gradual declines (glide)
The reason pulse and glide works is because your vehicle is so overpowered. The pulse utilises the excess energy to accelerate, and then gliding uses no fuel.
It is much better to convert the energy into height (go up steep hills) and then glide down gentle gradients with the engine off. Get the right gradients (you go uphill at the motor's sweetest bsfc and roll downhill at the speed you want) and you will never be beaten on consumption with an internal combustion. Height stores 100% of the excess energy thrown at it - a power pack in a hybrid stores maybe 40% if you are lucky. And it is 100% of excess that height stores - very precisely 100%.
Using person power is very different from an engine because we don't produce excess power. We are better off keeping the energy as sugars and converting the sugars to energy fairly precisely when we need it. Because we are using our pedaling energy efficiently we are better off riding on the flat rather than going uphill and gliding down.
Engines in cars waste a lot of energy (above the thermodynamic limits). An indication is the hybrid, where running the engine at only optimum efficiency and converting to power electricity, storage and back to electricity, at 40% efficiency, gives better results than using the engine for direct drive!!
To put that into perspective a car is generally wasting, above the thermodynamic limits, 60% of the energy.
|