Not for love of money, but of Humanity. "Greater is he who works for the good of all, then he who works for the good of himself only" ~ Matthew 25:40: "The King will reply, 'I tell you the truth, whatever you did for one of the least of these brothers of mine, you did for me.'"- (NIV). I live in Singapore where the Emperor must not be disturbed.

Thursday, March 31, 2011

"arent hybrids more wasteful?"

View Post ponpokku wrote:
Re: encouraging environmentally-friendly lifestyle
but... but... but... arent hybrids more wasteful? consider the coversion from heat to electrical then to chemical and lastly mechanical, as opposed to heat directly to mechanical?
Hybrids conserve energy by turning unwanted kinetic energy (car movement when brake applied) into electrical energy (dynamo applied to sap motion of car), stored as 'chem energy' in battery and reused to drive electric motor when accelerator is applied again.

Where battery power is too weak for electric motor to effectively power car, the combustion engine kicks in to generate mvt directly from fuel combustion.

Heat is the unwanted by product in any combustion engine and 60- 80% of the actual energy in petrol fails to convert to kinetic energy in internal combustion engines due to friction/ other losses manifested as unwanted heat/ sound energy dissipated.

Each hybrid car thus has 2 power sources, a combustion engine and a battery driven electrical motor, used alternately as programmed.

i'm very ill-informed on hybrids fyi...
Equally ill-informed on calorie counts, just jokin, have replied to you at 31Mar2011 [link]: [GPGT] Travel on bicycle is good for the environment.

At/ related:
31Mar2011: encouraging environmentally-friendly lifestyle


  1. i agree, they all say how 'green' these cars are but if you think about how you charge them and how much electricity they use is incredible, are we not told to use energy saving lightbulbs? energy saving devices? and then they say get an electric car which uses a 2000w charge supply?? makes no sense to me.
    kinetic energy

  2. Hi Bud, though 2000W (=2kWh) seems high compared to a light bulb (up to 0.1kWh), U should also be aware that 1 liter of petrol contains approximately 34.8 MJ/L []= 9.744kWh energy (1 MJ ≈ 0.28 kWh)
    No question, all >/= 4 wheeled vehicles are energy guzzling machines because they are big and heavy machines that move people around. The benefit of using battery powered veh is that large commercial power generators are more efficient at energy extraction then internal combustion engines and so the relative savings in costs and CO2 emissions.


    1. Cont'd: as I understand, internal combustion engines (e.g. car/ bus etc) are only 30% efficient (means 70% of gasoline energy is lost as heat and noise energy rather than for linear motion). The most efficient steam turbines are 60% efficient ( ) - double that of the internal combustion engine- the greater efficiency of larger turbines is what gives electric/ hybrid cars the better energy efficiency and thus reduced fuel costs.