The Still engine was a

piston engine A reciprocating engine, also often known as a piston engine, is typically a heat engine that uses one or more reciprocating pistons to convert high temperature and high pressure into a rotating motion. This article describes the common featu ...

that simultaneously used both

steam power A steam engine is a heat engine that performs mechanical work using steam as its working fluid. The steam engine uses the force produced by steam pressure to push a piston back and forth inside a cylinder. This pushing force can be trans ...

from an external

boiler A boiler is a closed vessel in which fluid (generally water) is heated. The fluid does not necessarily boil. The heated or vaporized fluid exits the boiler for use in various processes or heating applications, including water heating, central h ...

, and

internal combustion An internal combustion engine (ICE or IC engine) is a heat engine in which the combustion of a fuel occurs with an oxidizer (usually air) in a combustion chamber that is an integral part of the working fluid flow circuit. In an internal combus ...

from

gasoline Gasoline (; ) or petrol (; ) (see ) is a transparent, petroleum-derived flammable liquid that is used primarily as a fuel in most spark-ignited internal combustion engines (also known as petrol engines). It consists mostly of organic co ...

diesel Diesel may refer to: * Diesel engine, an internal combustion engine where ignition is caused by compression * Diesel fuel, a liquid fuel used in diesel engines * Diesel locomotive, a railway locomotive in which the prime mover is a diesel engin ...

, in the same unit. The

waste heat Waste heat is heat that is produced by a machine, or other process that uses energy, as a byproduct of doing work. All such processes give off some waste heat as a fundamental result of the laws of thermodynamics. Waste heat has lower utility ...

from the

cylinder A cylinder (from ) has traditionally been a three-dimensional solid, one of the most basic of curvilinear geometric shapes. In elementary geometry, it is considered a prism with a circle as its base. A cylinder may also be defined as an infin ...

and internal combustion exhaust was directed to the steam boiler, resulting in claimed fuel savings of up to 10%.

History

The inventor,

William Joseph Still William Joseph Still was an English engineer. He was born at Reigate on 17 August 1870. In 1884, he went to Canada to work for a firm of electric vehicle manufacturers. In 1894, he returned to England, where he invented a double-acting diesel-st ...

, patented his device in 1917 and on 26 May 1919 in London he and his collaborator Captain Francis Acland (1857–1943, a consulting engineer formerly of the

Royal Artillery The Royal Regiment of Artillery, commonly referred to as the Royal Artillery (RA) and colloquially known as "The Gunners", is one of two regiments that make up the artillery arm of the British Army. The Royal Regiment of Artillery comprises t ...

) announced it at a meeting, chaired by

steam turbine A steam turbine is a machine that extracts thermal energy from pressurized steam and uses it to do mechanical work on a rotating output shaft. Its modern manifestation was invented by Charles Parsons in 1884. Fabrication of a modern steam turbin ...

inventor

Charles Algernon Parsons Sir Charles Algernon Parsons, (13 June 1854 – 11 February 1931) was an Anglo-Irish engineer, best known for his invention of the compound steam turbine, and as the eponym of C. A. Parsons and Company. He worked as an engineer on dy ...

, at the

Royal Society of Arts The Royal Society for the Encouragement of Arts, Manufactures and Commerce (RSA), also known as the Royal Society of Arts, is a London-based organisation committed to finding practical solutions to social challenges. The RSA acronym is used m ...

. Acland described a continuous process by which a

double-acting cylinder In mechanical engineering, the cylinders of reciprocating engines are often classified by whether they are single- or double-acting, depending on how the working fluid acts on the piston. Single-acting A single-acting cylinder in a reciprocat ...

is powered on one side by internal combustion and on the other by steam from a boiler heated principally by the waste heat from the water jacket and exhaust gases. He explained how the reserve of energy represented by the steam pressure in the boiler provided for any occasional overload which would defeat a standard internal combustion engine of the same power. Independent heating of the boiler was occasionally used, to provide extra power for exceptional conditions, and in the first stage of operation to allow the engine to start itself from steam power alone, even against a load. Still was not the first in this field; a similar system, whereby compressed air (instead of gearing) was to transfer the power from an internal combustion engine and steam recovered from its cooling system was to augment the compressed air, had been patented in 1903 by Captain Paul Lucas-Girardville (a French military aviator) and Louis Mékarski.

Development

Marine

In 1924

Scotts Shipbuilding and Engineering Company Scotts Shipbuilding and Engineering Company Limited, often referred to simply as Scotts, was a Scottish shipbuilding company based in Greenock on the River Clyde. In its time in Greenock, Scotts built over 1,250 ships. History John Scott fou ...

of Greenock, Scotland, put a diesel-fuelled marine version, the Scott-Still regenerative engine, into production, with the first pair of engines installed in the twin-screw M. V. ''Dolius'', of the

Blue Funnel Line Alfred Holt and Company, trading as Blue Funnel Line, was a UK shipping company that was founded in 1866 and operated merchant ships for 122 years. It was one of the UK's larger shipowning and operating companies, and as such had a significan ...

. The trial was successful and in 1928 Blue Funnel commissioned a larger and faster ship, the ''Eurybates'', with this propulsion system. However the requirement to carry marine engineering officers certified with both steam and motor qualifications, meaning extra crew members and wages, and the extra complexity with consequent higher maintenance costs, offset the fuel savings and conventional diesel engines were later installed in their place.

Railway

In 1926

Kitson and Company Kitson and Company was a locomotive manufacturer based in Hunslet, Leeds, West Yorkshire, England. Early history The company was started in 1835 by James Kitson (businessman), James Kitson at the Airedale Foundry, off Pearson Street, Hunslet, ...

, locomotive builders of Leeds, England, produced a steam–diesel hybrid locomotive, the Kitson Still locomotive. This was loaned for trials to the

London and North Eastern Railway The London and North Eastern Railway (LNER) was the second largest (after LMS) of the " Big Four" railway companies created by the Railways Act 1921 in Britain. It operated from 1 January 1923 until nationalisation on 1 January 1948. At th ...

and used successfully to haul heavy coal trains, but the difference in the cost of coal used by a conventional locomotive, against the fuel oil used by the hybrid, was not great. When Kitson's failed in 1934, a failure to which the development costs of the hybrid locomotive had contributed, the receivers sold the machine for scrap.

Decline

Developments of larger diesel engines in the 1930s, with improved methods of

power transmission Power transmission is the movement of energy from its place of generation to a location where it is applied to perform useful work. Power is defined formally as units of energy per unit time. In SI units: :\text = \frac = \frac Since the develo ...

, meant that the principal advantages of the Still engine – the ability to provide for direct-drive starts from rest and additional power at times of temporary high load – was lost, and further development ended.

References

*{{Cite journal , last=Acland, first= Frank E. D. , title= A New Prime Mover of High Efficiency and British Origin , journal=Journal of the Royal Society of Arts , volume= 67 , issue=3472 , date=1919 , pages=463–82 , jstor= 41347980 Steam engines Diesel engines Marine propulsion