Sir Harry Ricardo (26 January 1885 – 18 May 1974) was one of the foremost engine designers and researchers in the early years of the development of the internal combustion engine.
He improved on the engines that were used in the first tanks, oversaw the research into the physics of internal combustion that led to the use of octane ratings, was instrumental in development of the sleeve valve engine design, and invented the Diesel pre-combustion chamber that made high-speed diesel engines possible.
Harry Ricardo was born at 13 Bedford Square, London
in 1885, the eldest of three children, and only son of Halsey Ralph Ricardo, an architect, and his wife Catherine Jane, daughter of Sir Alexander Meadows Rendel
, a civil engineer. Ricardo was descended from a brother of the famous political economist David Ricardo
. He was one of the first people in England to see an automobile when his grandfather purchased one in 1898. He was from a wealthy family and educated at Rugby School
. In 1903 he joined Trinity College, Cambridge
as a civil engineering
student. Ricardo had been using tools and building engines since the age of ten.
In 1904, at the end of his first year, he decided to enter the University Automobile Club's event, which was a competition to design a machine that could travel the furthest on a quart (1 L) of petrol. His engine was a single cylinder one and the heaviest entered, but his motorcycle design nevertheless won the competition, having covered a distance of forty miles. He was then persuaded to join the Professor of Mechanism and Applied Mechanics, Bertram Hopkinson
, working on research into engine performance. He graduated with a degree in 1906 and spent a further year researching at Cambridge
Before graduation, Ricardo had designed a two-stroke motorcycle engine in order to study the effect of mixture strength upon the combustion process. When he graduated, a small firm, Messrs Lloyd and Plaister, showed an interest in making the engine. Ricardo produced designs for two different sizes, and the smaller one sold about 50 engines until 1914, when the war halted production.
In 1909 he designed a two-stroke 3.3 litre engine, for his cousin Ralph Ricardo, who had started up a small car manufacturing company, “Two Stroke Engine Company”, at Shoreham-by-Sea. The engine was to be used in a car called the “Dolphin”. The cars were well made but it became apparent that they were costing more to make than the selling price. The company had better luck making two-stroke engines for fishing boats. However, in 1911 the firm folded and Ralph left for India. Ricardo continued to design engines for small electric lighting sets, that were produced by two companies up to 1914.
In 1911 Ricardo married Beatrice Bertha Hale, an art student at the Slade School of Art
, in London. Her father, Charles Bowdich Hale, was the Ricardos’ family doctor. They had three daughters, and lived most of their married life at Shoreham-by-Sea
in West Sussex
In 1915 Ricardo set up a new company, “Engine Patents Ltd.”, which developed the engine that would eventually be used in the first successful tank design, the British Mark V
. The Daimler engine used in the Mark I created copious amounts of smoke, which easily gave away its position. Ricardo was asked to look at the problem of reducing smoky exhaust gases and decided that a new engine was needed. Existing companies were able to undertake construction of such an engine but not the design, so Ricardo designed it himself. As well as having reduced smoke emissions, the new engine was much more powerful than the existing ones. The new six-cylinder engine produced 150 h.p., compared with 105 h.p., and later modifications produced 225 h.p. and 260 h.p. By April 1917 one hundred engines were being produced a week. A total of over 8,000 of his tank engines were put into military service, making it the first British-designed engine to be produced in large numbers. The Mark IX tank
and the British version of the Mark VIII (tank)
also used a Ricardo engine. In addition to being fitted to tanks, several hundred of the 150 h.p. engines were used in France for providing power and light to base workshops, hospitals, camps, etc.
In 1917 his old mentor, Bertram Hopkinson
, who was now Technical Director at the Air Ministry
, invited him to join the new engine research facility at the Department of Military Aeronautics, later to become the RAE
. In 1918 Hopkinson was killed while flying a Bristol Fighter
, and Ricardo took over his position. From that point on the department produced a string of experimental engines and research reports that constantly drove the British, and world, engine industry.
One of his first major research projects was on the problems of pre-ignition, known as knocking or pinging. To study the problem he built a unique variable-compression test engine. This led to the development of an octane rating system for fuels, and considerable investment into octane improving additives and refining systems. The dramatic reduction in fuel use as a result of higher-octane fuel was directly responsible for allowing Alcock and Brown to fly the Atlantic in their Vickers Vimy bombers adapted with his modifications.
Advances in engine design
In 1919 Ricardo was studying the phenomena affecting the combustion within the petrol engine and the diesel engine
. He realised that turbulence
within the combustion chamber
increased flame speed, and that he could achieve this by offsetting the cylinder head
. He also realised that making the chamber as compact as possible would reduce the distance that the flame had to travel and would reduce the likelihood of detonation. He later developed the induction swirl chamber, which was an attempt to achieve orderly air motion in a diesel engine, the swirl being initiated by inclined ports
and accentuated by forcing the air into a small cylindrical volume. Finally he developed the compression swirl chamber for diesel engines. This design embodied intense swirl with a reasonable rate of pressure rise and good fuel consumption.
The compression swirl chamber design was called a “Comet” design and was subsequently licensed to a large number of companies for use in trucks, buses, tractors and cranes, as well as private cars and taxis. A Comet combustion chamber was used in the first Associated Equipment Company (AEC) diesel buses operated in 1931 by London Transport. A later development of it featured in the world's first volume production diesel passenger car, the 1933 Citroën Rosalie. This meant that Britain led the world in the field of high-speed diesels for road transport at that time. This advantage was lost to the continent as a result of the heavy tax imposed on diesel fuel in the budget of 1938.
In 1922 and 1923 Ricardo published a two-volume work “The Internal Combustion Engine”
In 1927 he formed Ricardo Consulting Engineers in Shoreham-by-Sea, which has become one of the foremost automotive consulting firms worldwide and is publicly listed on the London Stock Exchange.
Although Ricardo did not invent the sleeve valve, in 1927, he produced a seminal research paper that outlined the advantages of the sleeve valve, and suggested that poppet valve engines would not be able to offer power outputs much beyond 1500 hp (1,100 kW). A number of sleeve valve aircraft engines were developed following this paper, notably by Napier, Bristol and Rolls-Royce. Bristol produced the Perseus, Hercules, Taurus and the Centaurus, Napier produced the Napier Sabre, and Rolls-Royce produced the Eagle and Crecy, all using sleeve valves.
In 1929 Ricardo was elected Fellow of the Royal Society.
World War II
Ricardo’s work on the sleeve valve affected the development of British aircraft engines in the thirties and during the war. He even enhanced the famous Rolls-Royce Merlin
engine in the Mosquito
by giving it an oxygen enrichment system to improve its performance.
Ricardo's work exerted influence all around the world. While his work guaranteed England a supply of fuels of ever-increasing power during the 1930s, it also enabled Germany to produce synthetic high-octane aviation fuel, for example for the Focke-Wulf Fw 190 which inflicted heavy losses among the RAF's Supermarine Spitfires in 1942. Likewise, Ricardo's research on the detonation-inhibiting qualities of water injection was exploited by German engineers (MW 50) to provide their aero-engines with a particularly powerful special emergency power rating.
During 1941-5 Ricardo was a member of the War Cabinet engineering advisory committee.
Ricardo also assisted in the design of the combustion chambers and fuel control system of Sir Frank Whittle’s jet engine.
Post war period
In 1944 Ricardo was elected president of the Institution of Mechanical Engineers
. In 1945 he and his wife moved from Shoreham-by-Sea to Graffham
, also in West Sussex
. In 1948 Ricardo was knighted in recognition for his work in the field of internal combustion engineering.
In 1964 Ricardo retired from active work in Ricardo Consulting Engineers but kept in touch with various engineers within the company.
In 1974, at the age of 89, Ricardo broke his leg in a fall. He died six weeks later, on 18 May.
On 16 June 2005 a blue plaque was placed outside the house where he was born in Bedford Square, London.
During the 1960s a second round of development of the Comet system was started, now armed with considerably more powerful test apparatus. The refined design was immediately used in several cars, and the pre-combustion system remains in use in most diesel engines today. Ricardo Consulting remains committed to the diesel, considering it to be nowhere near its development potential even in the most advanced of today's engines.
In 1978 the US Department of Energy hired Ricardo Consulting to research the Stirling engine as a car engine. A series of engines, eventually forty-five in total, were built to test this system and showed very low emissions, but the efficiency was compromised by the need to operate under transient conditions -- the design was best running at a single speed, making it less than useful as a car engine. The Stirling may make an excellent engine for hybrid cars and has recently generated some interest in this role.
In 1986, the Voyager was the first aircraft to fly around the world non-stop and without refuelling. Ricardo Consulting redesigned the otherwise "stock" Teledyne Continental engine to incorporate a highly efficient combustion system and water cooling, thereby dramatically reducing drag and improving fuel economy.
Ricardo had worked on direct injection gasoline engines for aircraft engines from the 1930s; but work on diesels finally started to come to fruition in the 1990s. Today several stratified charge engines are in use in the automobile market, designs that would not have existed without his constant work on them.