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Design of Exhaust Systems for V-Twin Motorcycle Engines to Meet Silencing and Performance Criteria
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Abstract
This paper reports on the use of mathematical modelling by the GPB method of pressure wave propagation through finite systems, for the design of prototype exhaust systems and silencers for a Harley-Davidson motorcycle. The motorcycle engine is the classic 1340 cm3 45° V-twin power unit. The design objectives were to gain mid-range power and torque without loss of performance at either end of the speed range and to design silencers which would enhance the performance and the noise image of the machine.
The Queen's University of Belfast (QUB) (3)* employed their unsteady gas flow modelling techniques to the design of the system and its silencers to complement a new camshaft design from Crane Cams. The results of the use of these computer based design techniques are reported as performance characteristics of power and torque for the new design by comparison with the stock system. The comparisons reported are both computed performance characteristics and for those measured experimentally on a chassis dynamometer.
Also shown are the computer predictions for the pressure diagrams at the exhaust valve for the stock and the QUB systems, which pressures heavily influence the ensuing airflow through the engine and the torque which is subsequently attained.
The design of the silencers enhances the behaviour of wave action within the exhaust system, so that the engine produces more power and less noise with silencers fitted to the QUB system by comparison with open straight pipes. Measurements are provided to illustrate this point.
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Blair, G., Cahoon, W., and Yohpe, C., "Design of Exhaust Systems for V-Twin Motorcycle Engines to Meet Silencing and Performance Criteria," SAE Technical Paper 942514, 1994, https://doi.org/10.4271/942514.Also In
References
- Kirkpatrick S.J. Blair G.P. Fleck R. McMullan R.K. “Experimental Evaluation of ID Computer Codes for the Simulation of Unsteady Gas Flow Through Engines - a First Phase” SAE International Off-Highway Meeting Milwaukee September 1994 SAE Paper no. 941685 18
- Blair G.P. “The Basic Design of Two-Stroke Engines” SAE 1-56091-008-9 March 1990 672
- Blair G.P. “The Basic Design of Two-Stroke Engines” SAE ‘The Theory of Unsteady Gas Flow Through Engines’ 2nd 1995 141
- Lax P.D. Wendroff B. “Systems of Conservation Laws” Communs. Pure Appl. Math. 15 1960 217 237
- Chen C. Veshagh A. Wallace F.J. “A Comparison Between Alternative Methods for Gas Flow and Performance Prediction of Internal Combustion Engines” Society of Automotive Engineers International Off-Highway & Powerplant Congress Milwaukee, Wisconsin September 9-12 1991 SAE Paper No. 921734
- Blair G.P. “An Alternative Method for the Prediction of Unsteady Gas Flow through the Reciprocating Internal Combustion Engine” Society of Automotive Engineers International Off-Highway & Powerplant Congress Milwaukee, Wisconsin September 9 12 1991 SAE Paper No. 911850 SP883 137 162
- Blair G.P. “Correlation of an Alternative Method for the Prediction of Engine Performance Characteristics with Measured Data” Society of Automotive Engineers, International Congress Detroit, Michigan March 1993 SAE paper No. 930501 20
- Blair G.P. “Correlation of Measured and Calculated Performance Characteristics of Motorcycle Engines” Graz, Austria 22-23 April 1993 5 16
- Blair G.P. Magee S.J. “Non-Isentropic Analysis of Varying Area How in Engine Ducting” Society of Automotive Engineers International Off-Highway & Powerplant Congress Milwaukee, Wisconsin September 13-16 1993 SAE Paper No. 932399 77 94
- Blair G.P. “Non-Isentropic Analysis of Branched Flow in Engine Ducting” Society of Automotive Engineers, International Congress Detroit, Michigan March 1994 SAE paper No. 940395 55 72
- Benson R.S. Horlock J.H. Winterbone D.E. “The Thermodynamics and Gas Dynamics of Internal Combustion Engines” 1 Clarendon Press Oxford 1982
- Blair G.P. Goulburn J.R. “An Unsteady Flow Analysis of Exhaust Systems for Multi-Cylinder Automobile Engines” Society of Automotive Engineers, Mid-Year Meeting Chicago, Illinois May 19-23 1969 SAE Paper No. 690469 16
- Blair G.P. Spechko J.A. “SoundPressure Levels Generated by Internal Combustion Engine Exhaust Systems” SAE Automotive Congress Detroit 1972 SAE Paper No. 720155 11
- Blair G.P. Coates S.W. “Noise Produced by Unsteady Exhaust Efflux from an Internal Combustion Engine” SAE Automotive Congress Detroit January 1973 SAE Paper no. 730160 1973 13
- Coates S.W. Blair G.P. “Further Studies of Noise Characteristics of Internal Combustion Engines” SAE Farm, Construction and Industrial Machinery Meeting Milwaukee, Wisconsin September 1974 SAE Paper No. 740713 14
- Bingham J.F. Blair G.P. “An Improved Branched Pipe Modelfor Multi-Cylinder Automotive Engine Calculations” Proc.I.Mech.E. 199 1985 65 77
- Blair A.J. Blair G.P. “Gas Flow Modelling of Valves and Manifolds in Car Engines” Proc.I.Mech.E., International Conference on Computers in Engine Technology University of Cambridge April 1987 131 144
- Annand W.J.D. Roe G.E. “Gas Flow in the Internal Combustion Engine” Foulis, Somerset 085429 1601 June 1974
- Blair G.P. Kirkpatrick S.J. Fleck R. “Experimental validation of a 1D modelling code for a pipe containing gas of varying properties” SAE Automotive Congress Detroit March 1995
- Blair G.P. Kirkpatrick S.J. Mackey D.O. Fleck R. “Experimental validation of ID modelling codes for a pipe system containing area discontinuities” SAE Automotive Congress Detroit March 1995