OCTOBER 2, 2000

What we know about the new Renault V10

When Renault announced plans to withdraw from Formula 1 in January 1997, the company chairman Louis Schweitzer said that the firm would be back "in three or four years".

When Renault announced plans to withdraw from Formula 1 in January 1997, the company chairman Louis Schweitzer said that the firm would be back "in three or four years". At the time Renault had other things to worry about. The company needed to cut costs and Schweitzer did not want to cutting jobs while being seen to spend large sums in Formula 1.

So Renault quit the sport and Schweitzer and his assistant Carlos Ghosn (now in charge of Nissan) axed thousands of jobs. The intention to return to Formula 1 remained unchanged and Renault kept in touch with F1 engine development through its involvement with Mecachrome, which took over the old Renault engines. Renault Sport kept a small group of engineers working on F1 development but quite a few of the old Renault Sport team departed. Technical Director Bernard Dudot moved to Prost Grand Prix and one or two of his colleagues from the early years at Renault Sport went into retirement. Of the younger generation engine designer Jean-Jacques His was ordered to go back into the mainstream at Renault and began working on the development of a direct injection engine in his role as Director of Strategy and Long-Term Development in Renault's Engineering Division.

Renault Sport was placed under the control of an American engineer named John Topolski, who switched across from Renault's research and development division. Topolski's main task was to design the Morane Renault MR250 aero-engine.

The Mecachrome engines - which later became known as Supertec V10s - proved little more than developments of the Renault RS9 engine, which was introduced in 1997. The Supertec engines of today are not that different to the RS9 despite what the Supertec management would like everyone to believe.

At the start of 1999 Topolski and his team were given the go-ahead and the budget to start development on a new generation Formula 1 engine. The brief was for the company to try out some wild ideas beyond the usual scope of F1 engine development to find some innovative solutions to the problems that exist. In the summer His gave up his mainstream job and returned to Renault Sport as the new technical director.

The problem for His and his colleagues is that the normally-aspirated V10 engine has been under intensive development for the last 14 years. Nowadays it is difficult for one engine company in F1 to find an advantage over another. Gradually the engines have been getting smaller and lighter and the center of gravity has been getting lower. The revs have risen and more power is being produced thanks to better combustion and lower friction but there are limits beyond which one cannot go unless new technologies are developed.

The rumors in recent months have been that the new Renault can rev to 21,000rpm. If true, this is remarkable because there are inherent torsional resonance problems with steel crankshafts above 19,000rpm. Crankshafts have to be made from either steel or cast iron.

History is dotted with such barriers. In the old Cosworth DFV days engines could not rev beyond 15,000rpm because the steel valve springs could not cope with more. That problem was solved (by Renault) with the introduction of the pneumatic valve but these are now operating at a rate of 315 times a second and cannot go faster. There are possibilities for electronically-operated valves which will get rid of the need for camshafts and allow faster valve action and will save a lot of weight. The problem for racing engines is that the computer operated actuators need to work 350 times per second if the rev ranges get up to 21,000rpm and in order to work that fast they need to be light. If the metals involved are too light the valves do not move.

The weight and size of engines could be reduced if direct injection systems could be developed for racing engines. At the moment such systems do not work well at high revs as there is not time for fuel to vaporize. This has been overcome in diesel engines by using higher pressure inside the engine but in gasoline engines the system is still not working well at high revs.

Other major issues in current F1 engine design are center of gravity, size and weight. The new Renault engine is rumored to have a 110-degree vee angle. This is appreciably wider than the current engines being raced. This lowers the center of gravity but makes the packaging much more complicated. The reason that teams have not used wide angle engines to date is that they have encountered vibration problems at certain angles which make the engines unreliable. No-one has yet solved this problem.

The size of the engines is also important and in order to build a shorter engine F1 engine makers have been looking at different configurations. Before the ban on 12-cylinder engines, Ferrari had worked with the University of Bologna to compare the relative merits of V12 and W12 layouts. The only way forward with 10-cylinder engines is to build "unbalanced" W-form engines with, for example, a bank of four cylinders flanked by two banks of three cylinders. This would have two major advantages over the current V10s as it would create an engine which would be 20% shorter and would use a shorter crankshaft and so could rev higher as torsional resonance of the crankshaft would also be reduced. But the packaging of such an engine would be very complicated and could have any number of implications on reliability.

In terms of weight, the revolution has happened. Most of the V10s are now in the 100kg range. This has been achieved through the switch from casting engine blocks to machining them, the latest computer-aided machining systems allowing for much more precision and, therefore, a lot less wastage. It is unlikely that much more progress will be made in weight-reduction as new rules being introduced next year ban the use of new composite metals in the crankshafts, camshafts, pistons, cylinder heads and cylinder blocks. There may be some weight to be gained in others area from these materials but this will not produce revolutionary weight gains.

Some think that Renault Sport engineers may have learned new tricks from the MR 250 aero-engine program but it is hard to see how development of a low-revving, four-cylinder turbocharged diesel engine can have much use for a high-revving gasoline racing engine although there may have been some knowledge gained about vibration, as this was an early problem with the MR250.

So is there really a secret or is Renault simply going to produce a state-of-the-art engine to compete with the best available today? The management of Renault Sport continues to say that the 2001 engines which will be used by Benetton will feature a lot of innovation.

They will not say more. They do not want the world to know their secrets.