Question

Use your own words to explain the following questions. Please no handwriting:

State the fuel savings of a mild hybrid and provide some examples of vehicles in this hybrid class.

Compare and contrast the efficiencies of electric motors and internal combustion engines.

Describe the fuel cell that is best suited for automotive applications and explain the reasons why.

Answer 1

1. MILD HYBRID:-
- these are on the other end of the spectrum of hybrid vehicles.
- These are classified as gasoline-electric vehicles, but the extent of how much car uses the electric motor is what defines them as mild.
- The big difference between a mild hybrid and a full hybrid is that the electric motor in a mild hybrid cannot actually propel the vehicle on its own.
  
Benefits:-
-benefit of the mild hybrid system is that it saves fuel by shutting off the gasoline engine when the vehicle is stopped, breaking or cruising.
- electric motor helps the gas engine restart with improved efficiency ,it is much more efficient than using the ignition to switch the engine on or off.

2. Electric engine:-
- it is based on principle of electromagnetism, and are driven by either triple phase AC current (in case of AC motors) or batteries (in case of DC motors).
- the only source of inefficiencies are friction and transmission loses.

combustion engines :- these are based on Carnot theory.
- with a carnot efficiency ( lower than 100%).
- so result is electric motors are 85-90% efficiy and combustion engine are <40% efficient.

3. Fuel cell best suitable for automotives is hydrogen fuelled cell because the only by product of this cell is water.