Ricardo Cylinder Heads

"With Ricardo combustion chambers the condition of the exhaust gases, under all speeds and the small spark advance necessary, indicate that the turbulence provided by this improved form of combustion chamber digs these layers of gas off the wall and hurls them into the midst of the flame where they burn and thus contribute their energy to the explosion during the effective period.

The Importance of Turbulence
"So far as is known, no laboratory in the world has carried out so thorough and lengthy research' on combustion chamber designs. In view of these facts we can speak with assurance on this subject. The following statement is of unusual importance:
"Up to recent years, so far as intentional design for the purpose was concerned, turbulence was neglected by all, et as a matter of fact, it is the thing that makes modern engines at all possible. Turbulence (Intl correct combustion chamber design are the first factors of iniportunce in all engine designs:
"During the war, Mr. Harry Ricardo, of Shore-ham, England, a follower of Clerk and Hopkinson, and the foremost among the younger foreign engineers, invented the now famous Ricardo combustion chamber for "ell" head engines.
"This construction is shown in Fig. 3 and conforms with all the known facts above mentioned, concern-
Fig. 3. This cut shows sectional view of Ricardo cylinder head, indicating by arrows the swirl of the gas mixture just prior to the passage of the ignition spark.

ing combustion chambers and among other things harnesses and capitalizes turbulence in "ell" head engines. There has been cordial and thorough co-operation for years between Ricardo & Company and our Company, who are justly proud to have been connected with the development of this very important improvement in internal combustion engines.
"Before the invention of the Ricardo head the turbulence was produced by the rush of gas by the intake valve. In common designs turbulence died out by the time the spark jumped.
"In the Ricardo combustion chamber, Fig. 3, note the compact form of chamber, the favorable location of spark plug and that turbulence is produced by the piston forcing the gas up into the chamber and causing a rapid swirling of the main body of the charge, thus distributing the flame rapidly throughout the mixture.
Compressions and Speeds
"In an average engine running at 2,000 r.p.m., the charge takes usually four-thousandths of one second to get up the maximum pressure. On an engine with the Ricardo head it takes only two-thousandths of a second to build up to a still higher pressure.
"It takes a wide variation of spark advance to handle an ordinary engine efficiently. In a recently equipped Ricardo head it takes only 14 degrees advance for all speeds up to 4,000 r.p.m.
"The rapid high speed burning, characteristic of the Ricardo combustion chamber, makes possible a 15 per cent improvement in economy and power at full load depending on other limiting factors. There is a possible improvement in quarter load economy of 50 per cent. Applied to motor car and truck performance and in connection with proper gear ratios, it may result in 100 per cent increase in miles per gallon of fuel.
"It has been proven in innumerable tests that at all compression ratios, loads or speeds, the highest ceonomiy is only possible by hneing the proper degree of tarbalrmce, compact forms of chamber and furoroble location of the spark, regardless of the kind of fuel."
The instruction book of the Fageol reads:
"When operating an engine equipped with a Ricardo head, it is important that the spark shall not be advanced too far.
"The following table shows the correct spark advance with both the old type and the Ricardo head:
Spark Advance Spark Advance
with Coven- with
R.P.M. tional Head Ricardo Head
400 8°
600 ll° 8°
800 14° 10°
1000 17° 12°
1200 20° 14°
"The fuel mixture in a Ricardo head burns much faster than in the conventional head, and because of this increased combustion speed, the explosion does not need to occur so soon.
"Some of the results accomplished by using the Ricardo head are as follows: Combustion is instantaneous; no after-burning or wasted heat; more power with less fuel; more speed; fast on getaway; tremendous pulling power; engine runs cooler."
1 Since this material on the subject of turbulence was written, there has been a great deal of additional research work done by the Waukesha Motor Co. and they state that changes which they have been able to incorporate in heads of experimental design show that it is possible so to design the combustion chamber that there will be no detonation, and that compressions as high as six to one can be carried with ordinary gasoline, and that with these heads it is possible to run with the spark on dead center and yet obtain the maximum horsepower.


Previous page  1927 Supplement Home  Next page

Carburetor Manuals: Ricardo Cylinder Heads