DELTAWING ENGINE
us to take out more weight. The block is less than 15kg, the sump is fully CNC machined from a billet of 7075, and is just 4kg, including the engine mount.’
ROAD CAR RELEVANCE Much of the criticism levelled at the car concerns its relevance to road cars. One leading engineer sniffed in the air at the car, saying that of course, as it was not built to any particular rules, it should not be taken seriously, but Nissan argues that it will learn much about 1.6-litre engines from this programme. Actually, there is an element of reverse engineering, with the RML team taking weight saving and friction reducing cues from Nissan. Nissan wanted a highly
efficient motorsport engine and RML delivered this, using as a
base the 1.6-litre DIG-T engine selected by Nissan. The racing unit retains all the concepts that the RML team believed to be useful in a racing application. The throttle body, for example, is taken from the Juke. ‘The concept behind it is lightweight,
so the reduction in friction. ‘We knew about racing engines. The dry sump system is a pure racing design, which evolved from the last engine that we designed. It is not the same, but it is similar – there have been changes, improvements and we
“This engine is all about efficiency”
low friction, high efficiency. They are the three parameters. Some of it is achieved using Nissan’s technology. Some of their production engines have low friction through the use of DLC coating and beehive valve spring, all linked to reducing the reciprocating mass of the valve return. The lower the mass, the lower the force to open the valve,
have carried on improving things.’ The plenum chamber is almost
comical by its small size, but clearly it works, as it was one of the few pieces that carried over from the interim engine to the new one that began testing in mid-April. The dry sump was also re-designed, and is just 87mm in height to the top of the stud on the sump side, so the majority of the chamber is just 79mm high. So efficient is the engine, in fact, that one tiny radiator is capable of cooling the engine, water and oil systems, offering an even greater saving of weight. Fuel consumption figures are always going to be hard
to quantify, and only some hard running at the Le Mans test day will start to give real performance indicators as to the true potential of the DeltaWing. As much of its potential
comes down to the aerodynamics as the engine, but RML has worked hard to deliver a small capacity, direct injection engine with the performonce to match. ‘This engine is all about
efficiency,’ says Martin. ‘The plenum design was constrained by packaging, as was sump height. Weight was obviously a big factor, as was low friction, a stratified charge and lean running, all designed to achieve best BSFC [Brake Specific Fuel Consumption] to ensure we use as little fuel as possible.’ What will happen to the engine post Le Mans has yet to be determined, but Don Panoz has a plan to use the car for the LMP2 or LMPC classes in the ALMS. For a car that was originally proposed to the IndyCar fraternity, and rejected, it would be fitting for it to be run in the US after all.
Above: every part of the engine was designed by RML, including the non-structural aluminium block, that weighs just 15kg
Above right: the crank and pistons (whose top surface cannot be shown as RML do not wish to reveal combustion chamber secrets just yet) were designed by RML and manufactured by Capricorn
Right: this small, single radiator is the only cooling matrix for the entire car
56
www.racecar-engineering.com • Le Mans
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