Some More Light on Diesel Combustion

Abstract

This paper discusses the process of combustion, as revealed by high speed cinematography, in a small high speed diesel. Two direct injection types and one prechamber type were examined, and combustion sequences are shown. The phenomena are complex, but the main features are:

(1)

In small engines much of the fuel strikes the chamber wall and moves along it.

(2)

Swirl is greater than has hitherto been supposed, squish much less.

(3)

Most of the flame is of the carbon-rich diffusion type.

(4)

Soot from very rich mixture is always formed at high loads, but can burn later leaving a clean exhaust.

(5)

Combustion knock does not seem to be related to the total fuel in the chamber on ignition, but rather to the amount of fast burning mixture present.

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References

Rothrock

A. M.

‘The N.A.C.A. apparatus for studying the formation and combustion of fuel sprays and the results from preliminary tests’, U.S. National Advisory Committee for Aeronautics, Report No. 429 1932.

Nagao

Kakimoto

‘Swirl and combustion in divided combustion chamber type diesel engines’. Trans. Soc. automot. Engrs, N.Y. 1962 70, 680.

Alcock

J. F.

Watts

‘The combustion process in high speed diesel engines’, Proc. Congrès International des Machines à Combustion (CIMAC) 1959 (Paris, 1960), p. 246.

Hempson

J. G. G.

‘Special control equipment for the Fastax camera’, Proc. Fifth International Congress on High Speed Photography 1959, p. 171.

Lyn

W. T.

Valdmanis

‘The application of high speed Schlieren photography to diesel combustion research’, J. photo. Science 1962 10.

Rothrock

A. M.

Waldren

C. D.

‘Some effects of injection advance angle, engine jacket temperature and speed on combustion in a compressionignition engine’, U.S. National Advisory Committee for Aeronautics, Report No. 525 1935.

Alcock

J. F.

‘Air swirl in oil engines’, Proc. Instn mech. Engrs 1934 128, 123.

Alcock

J. F.

Maclellan

G. D. S.

‘Thermocentrifugal convection’, Proc. Eighth International Congress on Theoretical and Applied Mechanics 1952 Instanbul, 1953, p. 385.

Dicksee

C. B.

The high-speed compression ignition engine 1940, p. 178 et seq. (Blackie, London).

10.

Austen

A. E. W.

Lyn

W. T.

‘Relation between fuel injection and heat release in a direct injection engine and the nature of the combustion processes’, Proc. Auto. Div. Instn mech. Engrs 1960–61, p. 47.