Until about 25 years ago, powertrain design had advanced little since the time of Nicholas Otto or Rudolf Diesel. Engines were designed and built on the basis of imitation, trial and error, accumulated experience, or the occasional flash of inventive genius. The pencil and drawing board were the main tools of the trade, occasionally supplemented by nothing more sophisticated than a slide rule or logarithmic table. All that has now changed as environmental concerns and legislation, customer demands for greater performance and fuel economy, and manufacturers’ need for increased reliability and durability have forced engineers throughout the industry to use new, high technology and, especially to take advantage of the enormous analytical power available with computers.
At the heart of this technological change and, indeed, at the vital centre of the world motor industry itself are a small number of independent Research & Development firms or institutes — no more than a handful — having the facilities and trained personnel to undertake basic research, design, analysis, and testing for the motor industry, and of these, only two — AVL in Austria and the Ricardo Group, located at Shoreham-by-Sea, Sussex — are able to carry out all aspects of engine, transmission, and vehicle integration research and development work.
The Ricardo Group was founded by H R (later Sir Harry) Ricardo, who for more than half a century immersed himself in the scientific investigation of engines of all kinds and became recognized as a world authority on internal combustion engine design. Established during the Great War, much of Ricardo’s work during its early years was for the Air Ministry though increasingly the company looked to other sources for research contracts. Supported by the Shell Petroleum Company, for example, Ricardo undertook fundamental and important research on fuel and combustion. Because of the confidential nature of the company’s relations with clients, few of Ricardo’s achievements have ever been made public, and until recently the company has shunned publicity.
Ricardo’s are known, if known at all, mainly for the ‘Comet Mk V’ combustion chamber used on virtually all indirect injection diesel engines, save those of Mercedes-Benz and Fiat.
As a result of the ‘Comet’ the name of Ricardo has been associated with diesels in the public mind, but the firm has a long history of research and development work on high-performance petrol engines. Some readers will no doubt recall that Ricardo was responsible for the 4-valve Triumph motorcycle engine of 1921, and in the following year designed the 3-litre Vauxhall 16-valve DOHC engine. It was an extremely advanced design and, at the time of its introduction, produced the ‘highest output ever obtained from an engine of this size’. Nowadays, petrol engines account for well over 50% of the company’s engine work. While most of this research and development naturally is focused on road vehicles ranging from mundane Eastern European saloons to turbocharged high-performance cars, the company has recently set up a special division, Ricardo Racing, whose plans and activities are described below. This division will not only involve the company more directly and deeply in motor racing and enable the firm to derive directly some of the benefits of racing, but it will also make available for the first time to the racing fraternity the considerable design, analysis, and manufacturing facilities possessed by Ricardo.
Since the days of the Vauxhall TT car of 1922, Ricardo Consulting Engineers has accumulated over 1000 man-years of experience within the engine design team alone, and the group, as a whole, now consists of close to 500 skilled, specialist employees located at four centres on two continents.
At the Shoreham-by-Sea site, there are over 90 test-beds, as well as rolling road facilities, anechoic chambers, and various other specialized test rigs. These facilities allow the company to develop engines of almost every type (petrol, diesel, or spark-ignited gas) and size from 5 hp two-stroke chain-saw engines up to 5000hp diesel locomotive powerplants.
In addition to its test facilities, Ricardo has exceptionally well equipped machine shops and design offices. As part of a comprehensive consultancy service, Ricardo has offered clients a prototyping facility capable of producing small batches of parts of the highest quality and with a minimum lead time. Recent additions to the workshops include sophisticated computer numerically-controlled (CNC) tools able to machine complex components quickly and precisely. In the past the firm’s machining facility was available only for in-house projects or as part of general development contract work for clients, but now these facilities will be offered directly to customers, such as racing firms, who may need at short notice a small number of precisely machined components.
Over the last ten years major investments have been committed to creating a computer aided design/computer aided manufacturing (CAD/CAM) capability. Complete engine lines can be designed and prototypes made largely by these systems. Jobs are now completed in a fraction of the time that such work traditionally took. Not long ago, for example, the company received a request from a large manufacturer for six prototype sets of overhead camshaft valve gear for cylinder heads of considerable sophistication. The ports, etc. had to be designed from scratch, and were fully machined, assembled and tested in under three weeks. If Ricardo is to succeed in the racing business, this is the sort of time scale to which the company will normally have to work. Such jobs can now be accomplished because the firm’s CAD/CAM systems and CNC tools will allow, for example, the profiling or reprofiling of inlet and exhaust ports, combustion chambers, and pistons directly from CAD definitions and dimensioned on screen drawings: the time consuming process of hand producing engineering drawings and patterns is no longer necessary.
CAD/CAM capability is by no means unique to Ricardo; most engineering firms these days use it to some degree. Systems can be purchased off the shelf, but some of the software used by Ricardo has been written or modified by the company to fit specific engine design requirements. But even the best computer systems are only as good as the people using them. As one might expect, the firm of Ricardo believes that its engineers with all their accumulated knowledge and undoubted skills are special and that it is the availability of skilled operators, not just design systems, that is the real service they are offering. Like CAD/CAM, the other sophisticated software package used at Ricardo is finite element (FE) analysis, a technique employed by them for over fifteen years to determine strength and potential stress characteristics of components under realistic dynamic operating conditions. The company, however, is also developing advanced post-processing FE systems with failure prediction modes that may be suitable to racing engine design.
Computational fluid dynamics (CFD) is another new tool being used by Ricardo to develop and improve breathing and combustion models which will be available to racing clients. With CFD, for example, the cooling system of an engine can be optimized relatively quickly by simulating coolant side boundary conditions precisely at any location in an engine. The firm’s engineers believe that these analytical facilities and programmes will enable Ricardo to eliminate many of the problems of racing engine design that normally are resolved only after a costly and time-consuming development period. Moreover, techniques like CFD in conjunction with combustion and airflow modelling can be used to liberate more power from racing engines. Much engine development up to the present, as Technical Director Martin Overington observed, has been playing with valve gear, ie, concerned with getting gases into or out of the cylinder; but the really difficult problems associated with fundamental combustion technology have been side-stepped by and large. Now, however, by using CFD, high-speed combustion photography, and laser doppler anemometry the enormously complex events that take place inside the combustion chamber can be analyzed systematically, and, it is anticipated, the process improved to release more power with less fuel.
As part of the company’s in-house research programme, Ricardo plan to take this computerised design process a stage further. Since 1984 the firm has participated in Alvey, a government sponsored project developing ‘expert’ systems. Sometimes referred to as ‘artificial intelligence’ programmes, these systems — when fully developed — will guide users on virtually all aspects of powerplant design and manufacture from the selection of design features, geometry, materials, and production processes; they will even offer suggestions on how to improve performance over parametric designs in current use. It may be an over-simplification of these developments (but not a too fanciful one) to say that at some time in the not so distant future, Ricardo engineers might be able to ask the company’s ‘expert’ system to design and prepare for manufacture a 3.5-litre Grand Prix engine. The designer will only need to key in design priorities, weights and outside dimensions, etc. and leave the rest to the ‘expert’ system.
For such a system to work, or indeed for the current highly sophisticated design systems to be used at all effectively, skilled and knowledgeable engineers are needed. Whereas only 10 years ago, design analysts were outnumbered by draughtsmen ten to one, now at Ricardo’s they comprise more than half of the technical design labour force. These engineers and technical specialists can draw on the firm’s extensive experience base. Probably no other company has been involved in researching, designing and developing such a wide variety of engines and related components for so many customers for such a long time. Moreover, as an independent consultancy firm, Ricardo may benefit from its independent status in several ways.
With over 120 clients worldwide, a company like Ricardo can gain a broad perspective on design and development problems common to the industry; in turn, individual motor industry clients benefit from this diffusion of experience and accumulation of knowledge. The relationship is symbiotic in another way. Every engine design involves a series of compromise over objectives (eg, strength v weight or peak output v a broad power band), materials and production methods v costs etc. The compromises or engineering decisions are arrived at by weighing and balancing qualities, singly and in combination, but the judgments that are made are never purely objective, they reflect a system of values, presumptions, and traditions that form a particular company’s or nation’s engineering culture. The widespread client base may help Ricardo avoid the mental blind spots and prejudices inherent in the engineering cultures that pervade nearly every manufacturer and the engineering schools of most nations.
Behind individual engineers and their personal experience and knowledge, stands the firm’s technical library and data base. Ricardo probably has the finest powerplant library in the United Kingdom, if not the world. It contains over 100,000 items and receives by subscription approximately 350 specialist periodicals. Use of the computerised data base and library resources is one of the unrivalled services offered to Ricardo clients. As a test of the system’s efficiency, the data base was interrogated to see if it could find a technical paper of which neither the title nor date of publication were known, only that it was on high performance aero-engines and had been given in Rome 1934. Within a few seconds after keying in the request, the full citation appeared on the screen and a copy of the article was made available within minutes.
Most of the current research and development work is focused on meeting recently legislated emissions requirements or the even more stringent ones projected for the 1990s. Although exhaust emissions for production petrol engines and diesels may seem far removed from racing, Ricardo believe that many of the analytical design techniques and facilities of the group are applicable to racing powerplant and racing car design. In early 1989, a separate racing division within the Ricardo Group was set up to co-ordinate the firm’s motoring activities. To date, involvement has been limited. Ricardo has designed, built, and sponsors a four-cylinder two-stroke engine for sidecar racing. Of unusual ‘Z’ configuration, this engine, which has been very successful in its class of racing, produces 272hp/litre. Though this amount is less than the 320hp/litre now developed by Grand Prix motorcycle engines of the same capacity and number of cylinders, it is a good output for a 500cc side-car engine which needs to trade off peak output for a broader band width of power. Racing at the highest international levels of the sport is very competitive, and the condition under which engines function, for example, are quite far removed from normal modes of operation, as many a firm has found to their detriment when they embarked on a racing programme. Every new venture has a learning curve, and it will be interesting to see how quickly Ricardo learns to be competitive at the highest levels of the sport.
Traditionally, racing engines, the acme of the engineer’s art, have been designed largely by empirically based methods. However, this approach has severe limitations, a fact demonstrated by the early difficulties and frequent revisions made to every one of the new engines developed for the 3.5-litre formula. A more sophisticated analytical design approach might have anticipated and eliminated many of the problems at the design stage, at least that is what Ricardo believe.
Certainly, it has become apparent that international motor sports requires high technology and scientific expertise and skills both in design and manufacture. The cost of acquiring or developing this capacity in-house is far beyond the resources of most racing teams and not, generally, very cost-effective for major companies to undertake. Since the Ricardo Group already has most of this technology and much expertise in place, it was decided to make these available to the racing world. Recently, the firm has put together a proposal for the design and initial development of a race engine for either Sports Prototype or Formula One; by using all the advanced tools and techniques described above, Ricardo believes that the design and development and a significant amount of in-car development can be completed within a space of two years, the sort of time frame racing clients are likely to require.
Racing clients coming to Shoreham-by-Sea will be able to take advantage of the company’s design and testing capabilities in four major areas. 1) high-speed actuation and camshaft drive mechanisms, including unique programmes on valve motion prediction, stress levels, oil film behaviour, camshaft torsional vibration characteristics; 2) crankshaft design, in particular 3-D crank vibration analysis, crankcase stiffness and bearing behaviour prediction; 3) thermal and stress analysis of block and heads by finite element methods; and 4) combustion chamber and inlet and exhaust system design using advanced simulation techniques, validated by test rig experiments, and taking advantage of the company’s large data base on combustion chamber and port shapes. Not only are these design facilities available, the company can also develop and build a transient test bench to optimize engine management systems for racing engines of up to 1000hp.
As became apparent during the 1989 Grand Prix season, a good gearbox, like the semi-automatic one on the Ferrari, in conjunction with a good engine can help reduce lap times considerably. Some years ago, Ricardo anticipated the greater integration of engines with transmissions, and acquired an expertise (through Ricardo-Tuck Inc., Livonia, Michigan) in this specialized area. Company engineers foresee even closer powertrain integration with a single micro-computer co-ordinating both engine and transmission to achieve optimum performance. Under the guidance of Peter Windsor Smith, formerly of Coventry Climax and latterly of Maxwell Transmissions, the Ricardo Group has schemes for a new concept, semi or fully automatic, 8-speed transmission featuring operation with ‘hot shifting’, a technique that reduces the time and power losses between gear changes. A transmission of this sort should appeal to racing car designers and drivers alike.
Finally, Ricardo intend to push the integrated approach in racing beyond the linkage of engine and transmission; for example, at the design stage, aerodynamics of a vehicle must be integrated with the powertrain design in such areas as the cooling system. Through another recently acquired subsidiary, Ricardo AS & A of Letchworth, the group will be able to offer to clients, as part of a racing package, vehicle concept and a sophisticated and proven aerodynamic design capability.
The actual racing experience of the company is limited which may be one reason why the approach of the racing division is now both general and flexible. The company has indicated a willingness to undertake a variety of racing type work. Ricardo will investigate the sort of small-scale but persistent problems that afflict most racing powerplants at some time during their development and operational cycles by making use of the full range of the group’s analytical and test facilities. If requested, however, the company is also prepared to design, prototype manufacture, develop, assemble and provide field support for a completely new racing engine/transmission combination, as well as its integration with the racing vehicle that it will power.
At present there are no plans to expand to include production of special, racing derived engines or cylinder heads, like Cosworth do, for example; but one cannot help but wonder whether this will change as the Ricardo Group bring its light even further out from under the bushel and becomes more deeply involved in racing. Automobile or motorcycle manufacturers may want to advertise their association with such a ‘high-tech’ company; it is not fanciful to imagine that before too long one might see emblazoned as a status symbol on the boot of a special high performance vehicles the name ‘Ricardo’. DDH