Chapter 7. Exhaust Fundamentals.|
11946 words. 32 illustrations.
Early emphasis on backpressure and flow between cylinders. Suction theories. Ejector exhausts on aircraft engines. Crude designs before extraction principles recognized. Dragster systems - a special case.
The Exhaust Process. Connection to valve events. Pressure changes in the cylinder. Limitations of backpressure reduction. Greater potential with pulse dynamics. Gas velocities. Exhaust pressure cycle.
Column Inertia. Dependence on velocity. Limitations.
A High Performance Single Cylinder System. Pulse reflection at the pipe end. The megaphone diffuser. Why diffusers can have odd shaped ends. An innovative diagram to indicate pulse and energy dispersion. The reverse cone and how it works.
Systems for Multi-cylinder Engines. Pipe joints and collectors. Pulse benefits with four or five cylinder groups. Tail pipe diffuser length change for different number of cylinders. More pulse and energy dispersion diagrams for different configurations.
The Twin Cylinder Engine. Separate systems. Two into one. Drawbacks. Close coupled two into one.
Three Cylinder Coupling. Pulse spacing. Close coupled three into one. Short (interference) coupled three into one system.
Four Cylinder Coupling. Four into two into one. Another look at the benefits of four into one. The broad arrow 12 cylinder. 16 cylinders. The flat four.
Five Cylinder Coupling. Five into one. Three into one plus two into one.
Six Cylinder Coupling. Inline, vee and horizontal opposed. Groups of three. Looks are not everything. Six into one. Groups of two.
Eight Cylinder Coupling. V8 single plane crank = two fours. Two plane crank. Irregular firing orders. Flow peaks and troughs. Limitations of four into one on each side. Four into two into one, different each side. Balance and X pipes. The cross-over system.
Exhausting an F1 Racing Engine. Coventry Climax V8 pioneer. The V10s - dual five into one. The five way collector. Changes of individual pipe areas. Unimportance of pipe bends. Diffuser/tailpipe.
Pipe Diameter and Length. A diagram showing how ideal pipe dimensions change with speed, etc.