While these other developments had been taking place Dorman engineers had been working on a new project which was to be the most important of all, the evolution of the first Dorman diesel engine, from its conception in 1927, to completion in 1929, and its launching into production in 1930. The diesel engine, had, of course, been around for some considerable time; a brilliant Yorkshire engineer called Herbert Akroyd Stuart had, as early as 1890, patented the notion of an engine in which the fuel could be injected into the cylinder to be ignited simply by the heat of the compressed air caused by the stroke of the piston. Mr. Stuart sold the manufacturing rights to the firm of Hornsbys in Lincoln the following year; by 1892 engines produced by the firm, to Mr. Stuart's identical design were being launched onto the market. A little later that same year Dr. Rudolf Diesel, in Germany, was to develop a new invention which later took his name, his first patent was for an engine the design of which was extremely similar to that of the Hornsby Akroyd engine. Moreover when actual performance
had perforce been taken into consideration a sad divergence appeared between that
of the Hornsby Akroyd and the results achieved by Dr. Diesel's brainchild, for the
latter fell so far beneath theoretical expectation as to render a timelag of some
five years necessary before the Diesel engine was ready for its potential customers.
By then (1897) Hornsbys were, of course able to congratulate themselves both on the
latest technical improvements of their engine design and performance and the increasing
This slice of engineering history serves both as a reminder that the diesel was not invented or even first perfected by Dr. Diesel but an Englishman (although naturally the development of the principle was due to the work of many English, French, German and American scientists during the last century) and as a partial explanation of why the English trade and technical press including Dorman sales literature ostentatiously referred to 'oil' or 'compression ignition' engines rather than diesel engines for a number of decades after the events described.
First Dorman Diesel
Booklet home page Page index Pages 22 & 23 Pages 26 & 27
that of Dorman Ricardo diesels; in fact within a very short period after production under Dorman Ricardo had began the name could be seen emblazoned across the radiators of lorries, cruising the highways across the face of Britain and beyond. Considering the quantity of commercial vehicles fitted with Dorman petrol engines which were already in service or were to join them later, it is hardly surprising that in the nineteen thirties Dorman's was to become almost a byword for dependability with the men who drove for their living; everywhere one looked a Dorman engined vehicle might reasonably be found, and everywhere that one was to be found a harsh word was rarely to be heard for it.
The remainder of the explanation is that only comparatively recently has the term
diesel come to be equated with the whole compression ignition principle; hitherto
a compression ignition engine diverging to any degree from the original Akroyd Stuart
or Diesel principle was simply, a 'compression ignition engine'. In fact Dorman have
never produced a true diesel and very few 'true' diesels now exist!
It is also an indication that between 1892 and 1927, the diesel engine had become quite thoroughly established as a type of prime mover by the time that Dorman decided to enter the field; this meant that the company would be able to go straight into a ready made market which indeed coincided largely with its existing petrol and paraffin engine market but also that before Dorman diesels were to achieve a national reputation they had to force and withstand the challenging competition from a variety of quarters where names as diesel engine manufacturers had already been established.
It was fortunate that the production of Dorman diesels began in the early thirties
as this was to coincide with the steady transfer, from their Foregate St. Works to
the new Tixall Road Works, of all Dorman manufacturing departments. Once established
in their more commodious premises Dorman were able to proceed unhampered with the
production of diesel engines right up till the present.
At one period in the development of the first Dorman diesel engine it appears that work was being carried out on an adaption of the French engine under the supervision of the bearded Mr. M. Dalton himself. However, the models finally produced stemmed from the design of Dorman's future Chief Engineer, Mr. William Mitchell, who was to continue as the source of most innovations and developments in Dorman diesel design until his retirement almost forty years later.
The first models were the twin and four cylinder, 2RB and 4RB, manufactured under the Acro Licence due to the use of a combustion system for which Acro, a German concern, held the rights. This licence restricted it to industrial applications. However, to enable Dorman to increase its scope and break into the commercial market the Ricardo combustion system was adopted as standard on Dorman diesels; diesel production under the Ricardo licence was not ultimately to cease altogether until well after the war. Thus the name that came in the 'thirties' to stand in equal pride of place beside Dorman petrol engines very short period after production under Dorman was
Dorman motor cycle club outing in the 1920s.
The first Dorman diesel engine.