Which engine is more efficient external combustion engine or internal combustion engine and why?

As the combustion process is used to provide a continuous heat input to the working gas, it is more controllable and potentially more efficient, cleaner and quieter than internal combustion engines.

What is the most efficient type of engine?

The new Wärtsilä 31 is the most fuel-efficient four-stroke engine currently available on the market. The diesel version of the engine consumes on average 8–10g/kWh less fuel compared with the closest competitor across its entire load range. At its optimum point this number can go as low as 165g/kWh.

Are internal combustion engines efficient?

Most internal combustion engines are incredibly inefficient at turning fuel burned into usable energy. The efficiency by which they do so is measured in terms of “thermal efficiency”, and most gasoline combustion engines average around 20 percent thermal efficiency.

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Why are internal combustion engines inefficient?

Gasoline engines often blow more than 80% of the energy produced out the tailpipe or lose that energy to the environment around the engine. The reasons combustion engines are so inefficient are consequences of the laws of thermodynamics. … During the combustion process the fuel is oxidized (burned).

What would be the possible advantages of external engine compared to internal combustion engine?

External combustion engines are discussed as possible alternatives to the internal combustion engine for vehicle propulsion. Potential advantages are low levels of exhaust pollution, quiet operation, high starting torque, and possible lower costs during a vehicle lifetime.

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).

Which fuel is most efficient?

Diesel engines generally achieve greater fuel efficiency than petrol (gasoline) engines. Passenger car diesel engines have energy efficiency of up to 41% but more typically 30%, and petrol engines of up to 37.3%, but more typically 20%.

What is the most fuel efficient car ever made?

25 All-Time Best Gas Cars by MPG

  1. 2000 Honda Insight. Combined MPG: 53. …
  2. 2010 Toyota Prius. Combined MPG: 50. …
  3. 1986 Chevrolet Sprint ER. Combined MPG: 48. …
  4. 1994 Geo Metro XFI. Combined MPG: 47. …
  5. 1986 Honda Civic Coupe HF. Combined MPG: 46. …
  6. 1995 Honda Civic HB VX. Combined MPG: 43. …
  7. 2010 Honda Civic Hybrid. Combined MPG: 42. …
  8. 1985 Pontiac Firefly. Combined MPG: 42.
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How much energy is lost in an internal combustion engine?

Currently, up to 65% of the heat energy produced in internal combustion engines is wasted.

How can you increase the efficiency of an internal combustion engine?

  1. Run the engine fuel-lean, that is, use excess air. It is well known that fuel-lean running improves the efficiency. …
  2. Higher compression ratio. …
  3. We need new cycles put into practical use. …
  4. Run the engine at optimum conditions, meaning low friction (modest engine speed) and low pumping work (air throttle more open).

Which engine is more efficiency 2 stroke or 4 stroke?

As far as efficiency goes, the 4-stroke certainly wins. This is due to the fact that fuel is consumed once every 4 strokes. Four-stroke engines are heavier; they weigh upwards of 50% more than a comparable 2stroke engine.

Where are internal combustion engines used?

Internal combustion engines (ICE) are the most common form of heat engines, as they are used in vehicles, boats, ships, airplanes, and trains. They are named as such because the fuel is ignited in order to do work inside the engine. The same fuel and air mixture is then emitted as exhaust.

What happens to fuel in a car engine?

In gasoline-powered vehicles, most of the fuel’s energy is lost in the engine, primarily as heat. Smaller amounts of energy are lost through engine friction, pumping air into and out of the engine, and combustion inefficiency.

What are disadvantages of external combustion engines?

Disadvantages of external combustion engines

  • Not suitable for low load requirements.
  • Leakage of working fluid.
  • Lubricant consumption.
  • Size of engine is relatively big.
  • Overall working temperature is high so great care and special building materials are required.
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What is difference between internal and external combustion engine?

The difference between external and internal combustion engines is quite straightforward and is made obvious by the difference in their names. … External engines have a working fluid that is heated by the fuel. Internal combustion engines rely on the explosive power of the fuel within the engine to produce work.

What are the two main types of external combustion engine?

See also

  • Organic Rankine cycle.
  • Steam engines.
  • Stirling engines.
  • Trochilic engine.
  • Internal combustion engine (ICE)
  • Nuclear power.
  • Solar thermal rocket (an externally heated rocket)
  • Naptha engine, a variant of the steam engine, using a petroleum liquid as both fuel and working fluid.