Are turbines more efficient than gasoline engines?
Base load gas turbine combined cycle power plants of >400 MW can provide full load efficiency of >60 percent. When running many thousand full load hours annually, such big plants clearly outperform any gas engine configuration as a function of reduced fuel spending.
How efficient are gas engines?
Sadly, even with regular car maintenance such as a tune-up or an oil change, today’s gasoline engines are only around 30 to 35 percent efficient, which means roughly 65 cents out of every dollar you spend on gas goes to waste.
At what RPM is an engine most efficient?
It is likely to be geared for 2500 rpm or so at that speed, yet for maximum efficiency the engine should be running at about 1000 rpm to generate that power as efficiently as possible for that engine (although the actual figures will vary by engine and vehicle).
What is the most efficient marine engine?
Finnish technology group Wärtsilä has introduced a gas-fueled version of its Wärtsilä 31 marine engine, which is recognized by Guinness World Records as the world’s most efficient 4-stroke diesel engine.
How can we increase the efficiency of an engine?
- Run the engine fuel-lean, that is, use excess air. It is well known that fuel-lean running improves the efficiency.
- Higher compression ratio.
- We need new cycles put into practical use.
- Run the engine at optimum conditions, meaning low friction (modest engine speed) and low pumping work (air throttle more open).
Is it better to accelerate quickly or slowly?
Accelerating requires more energy than steady state cruising, therefore requiring more fuel. Accelerating quickly requires more energy than accelerating slowly.
How is the efficiency of an engine reduced at high speeds?
At high speeds, efficiency in both types of engine is reduced by pumping and mechanical frictional losses, and the shorter period within which combustion has to take place. High speeds also results in more drag.
How does the air fuel ratio affect engine performance?
The engine performance in terms of power and fuel consumption is highly dependent on the air-fuel ratio. For a gasoline engine, the lowest fuel consumption is obtained at lean AFR. The main reason is that there is enough oxygen available to burn completely all the fuel which translates in mechanical work.
Why are gasoline engines better at high altitude?
For gasoline engines, you have to open up the throttle wider to achieve the same output at a high altitude. Opening the throttle wider adds more air. The less restrictive throttle lowers the work required to move the air into the cylinder —commonly called “throttle loss.”
Why are diesel engines more efficient than gasoline engines?
The reason for this is the working principle of a diesel engine: controlling load not through air mass (which is always in excess) but through fuel mass (injection time). Remember that a stoichiometric equivalence factor (λ = 1.00) means an air-fuel ratio of 14.7:1 for gasoline engines and 14.5:1 for diesel engines.