Adaptive ignition timing control for combustion engines
Adaptive ignition timing control for combustion engines
An adaptive method of controlling the spark timing of an internal combustion engine is described. The timing is adjusted to maximise the thermodynamic work of an individual cylinder which is derived cyclically from the measurement of cylinder press-are and crank, angle. Unlike systems previously described which maximise the output torque °of the engine and have a transient response limited by. the engi_tatransfer function this system can respond at each cylinder firing i7stroke. The transient response is now dependant on the number of engine firing cycles rather than, time, exhibiting more desirable characteristics.Three methods of computing the work done/cycle using cylinder pressure and volume-crank angle approximations are compared.. Only one is chosen and this is based on a summation of the product of pressure and approximate change in volume per crank angle degree. Results for the work done/cycle versus timing show an assymetrical bill which exhibits considerable variations for a particular timing value. The assymetrical shape of the hill was not expected from the constant volume air cycle but was verified by a combustion mrdel developed to allow for practical deficiencies such zs:fla- speed,dissociation and. heat lost. Although the results from this model exhibit the same trends as practical results some of the approximations are too gross to allow the model to be used as a direct replacement for the engine process.,.The controller performance is investigated using typical results obtained from practical measurements. From these measurements the mean work done/cycle curve is represented by a dual quadratic and the work done variations, due to cycle-by-cycle combustion variations are considered to be represented by two independent, normal distributions added to the timing input and the work done output.Five different types of recursive controllers based on a gradient method are simulated and their performance is compared to that of similar practical controllers. It is concluded from the results that the engine controller model cannot, be rejected and that it is feasible to achieve a controlle that exhibits a transient response of less than 10 firing cycles with a steady state loss in work done/3
University of Southampton
1976
Werson, Michael John
(1976)
Adaptive ignition timing control for combustion engines.
University of Southampton, Doctoral Thesis.
Record type:
Thesis
(Doctoral)
Abstract
An adaptive method of controlling the spark timing of an internal combustion engine is described. The timing is adjusted to maximise the thermodynamic work of an individual cylinder which is derived cyclically from the measurement of cylinder press-are and crank, angle. Unlike systems previously described which maximise the output torque °of the engine and have a transient response limited by. the engi_tatransfer function this system can respond at each cylinder firing i7stroke. The transient response is now dependant on the number of engine firing cycles rather than, time, exhibiting more desirable characteristics.Three methods of computing the work done/cycle using cylinder pressure and volume-crank angle approximations are compared.. Only one is chosen and this is based on a summation of the product of pressure and approximate change in volume per crank angle degree. Results for the work done/cycle versus timing show an assymetrical bill which exhibits considerable variations for a particular timing value. The assymetrical shape of the hill was not expected from the constant volume air cycle but was verified by a combustion mrdel developed to allow for practical deficiencies such zs:fla- speed,dissociation and. heat lost. Although the results from this model exhibit the same trends as practical results some of the approximations are too gross to allow the model to be used as a direct replacement for the engine process.,.The controller performance is investigated using typical results obtained from practical measurements. From these measurements the mean work done/cycle curve is represented by a dual quadratic and the work done variations, due to cycle-by-cycle combustion variations are considered to be represented by two independent, normal distributions added to the timing input and the work done output.Five different types of recursive controllers based on a gradient method are simulated and their performance is compared to that of similar practical controllers. It is concluded from the results that the engine controller model cannot, be rejected and that it is feasible to achieve a controlle that exhibits a transient response of less than 10 firing cycles with a steady state loss in work done/3
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Published date: 1976
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Local EPrints ID: 462826
URI: http://eprints.soton.ac.uk/id/eprint/462826
PURE UUID: 58ab7695-c23e-42c5-9717-75b7ca264e0f
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Date deposited: 04 Jul 2022 20:12
Last modified: 04 Jul 2022 20:12
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Author:
Michael John Werson
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