Diesel Cycle: Difference between revisions
From wikiluntti
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Cylinder.png| The size of the combustion chamber of MB W211. | Cylinder.png| The size of the combustion chamber of MB W211. | ||
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=== Diesel-air Mixture === | |||
The heat capacity ratio (known as the adiabatic index) for a diesel-air mixture is typically around 1.4. | The heat capacity ratio (known as the adiabatic index) for a diesel-air mixture is typically around 1.4. | ||
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|+ Caption text | |||
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| 14.5:1 || Near-stoichiometric; good combustion efficiency but higher emissions. | |||
|- | |||
| 16:1 || Balanced performance; good power output and efficiency. | |||
|- | |||
| 18:1 || Lean burn; improved fuel economy but potential for higher NOx emissions. | |||
|} | |||
=== MB data === | |||
Mercedes Benz W211 (2003) | Mercedes Benz W211 (2003) | ||
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Bore x stroke gives V = 6xπ(8.8/2)<sup>2</sup> x 8.84 cm<sup>3</sup> = 3225.95cm<sup>3</sup>, which is rather close. | Bore x stroke gives V = 6xπ(8.8/2)<sup>2</sup> x 8.84 cm<sup>3</sup> = 3225.95cm<sup>3</sup>, which is rather close. | ||
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Revision as of 22:25, 23 March 2026
Introduction
-
Diesel Cycle
-
Diesel Cycle
Ratio of specific heats (heat capacity ratio) is defined as
- Isentropic (adiabatic) expansion
- Isochoric cooling (Qout): Heat rejection. Power stroke ends, heat rejection starts.
- Isobaric compression: Exhaust
- Isobaric expansion: Intake
- Isentropic (adiabatic) compression
- Isobaric heating (Qin): Combustion of fuel (heat is added in a constant pressure;)
Engine displacement is the cylinder volume swept by all of the pistons of a piston engine, excluding the combustion chambers. A combustion chamber is part of an internal combustion engine in which the fuel/air mix is burned.
Realistic Diesel Cycle
-
The size of the combustion chamber of MB W211.
Diesel-air Mixture
The heat capacity ratio (known as the adiabatic index) for a diesel-air mixture is typically around 1.4.
| 14.5:1 | Near-stoichiometric; good combustion efficiency but higher emissions. |
| 16:1 | Balanced performance; good power output and efficiency. |
| 18:1 | Lean burn; improved fuel economy but potential for higher NOx emissions. |
MB data
Mercedes Benz W211 (2003)
- Engine displacement: 3222 cm3
- Bore x Stroke: 88.0 x 88.4 mm3
- Compression Ratio: 18.0
Bore x stroke gives V = 6xπ(8.8/2)2 x 8.84 cm3 = 3225.95cm3, which is rather close.
