Fish hook curve

The fish hook curve shows the specific fuel consumption and the effective mean pressure of an internal combustion engine as a function of the air ratio . To create the diagram, the throttle valve position and the engine speed are kept constant and only the air ratio is varied. For each λ value, there is an associated specific fuel consumption and an effective mean pressure. ${\ displaystyle b _ {\ text {e}}}$ ${\ displaystyle p _ {\ text {me}}}$ ${\ displaystyle \ lambda}$ ${\ displaystyle \ lambda}$

For example, the following two points can be read from the curve on the right, which looks like a fish hook:

With an air ratio of , the effective mean effective pressure and thus the engine power output is maximum ( ). ${\ displaystyle \ lambda \ thickapprox 0 {,} 87}$ ${\ displaystyle p _ {\ text {e, max}}}$
With an air ratio of , the specific fuel consumption of the engine is minimal ( ). ${\ displaystyle \ lambda \ approx 1 {,} 1}$ ${\ displaystyle b _ {\ text {e, min}}}$

The operation of this motor therefore only makes sense within these two limits ( ). Exhaust gas aftertreatment using a three-way catalytic converter , however, requires an air ratio of exactly , which is why today's gasoline engines are usually operated at this value (see lambda control ). ${\ displaystyle 0 {,} 87 <\ lambda <1 {,} 1}$ ${\ displaystyle \ lambda = 1}$

Individual evidence

^ Franz Pischinger: Internal combustion engines . Lecture reprint. Ed .: Chair for Applied Thermodynamics, RWTH Aachen. 12th edition. tape 2 , 1991, 11.1.2 Efficiency and mean pressure, Fig. 11.1-9 Fish hook curve for a gasoline engine (With reference to K. Löhner, H. Müller "Mixture formation and combustion in the gasoline engine", in "The combustion engine", Volume 6, Springer Verlag Vienna , New York 1967).
^ Günter Merker, Christian Schwarz, Gunnar Stiesch, Frank Otto: Internal combustion engines . Simulation of combustion and pollutant formation. 3. Edition. BGTeubner Verlag, Wiesbaden 2006, ISBN 978-3-8351-0080-0 , 4.1.3 Combustion sequence , Fig. 4.6 Specific fuel consumption .

[1] Franz Pischinger: Internal combustion engines . Lecture reprint. Ed .: Chair for Applied Thermodynamics, RWTH Aachen. 12th edition. tape 2 , 1991, 11.1.2 Efficiency and mean pressure, Fig. 11.1-9 Fish hook curve for a gasoline engine (With reference to K. Löhner, H. Müller "Mixture formation and combustion in the gasoline engine", in "The combustion engine", Volume 6, Springer Verlag Vienna , New York 1967).

[2] Günter Merker, Christian Schwarz, Gunnar Stiesch, Frank Otto: Internal combustion engines . Simulation of combustion and pollutant formation. 3. Edition. BGTeubner Verlag, Wiesbaden 2006, ISBN 978-3-8351-0080-0 , 4.1.3 Combustion sequence , Fig. 4.6 Specific fuel consumption .