Nissan just made waves with their latest announcement about their Zero Emissions On Demand Race Car (ZEOD RC) that will be racing in this year’s 24 hours of Le Mans from the Garage 56 Technical Exhibition spot. When the car was first announced, Nissan wanted to make it a pure electric car and we took a look at the energy storage and recovery technologies that would be necessary to make that a possibility. Later during Chapter 1 of the build, Nissan had made the decision to make the car a hybrid with undisclosed powertrain details. Here is Chapter 2 of the ZEOD RC build that talks about nothing but the engine that will power the car. The new plan is to have the car run 11-12 lap stints around the Circuit de la Sarthe with one of those laps being done on pure electric power.
The rest of the laps will be powered by a 1.5 liter, 3 cylinder engine which cranks out 400 horsepower and 280 foot-pounds of torque despite the short block weighing only 88 pounds. It seems that 2014 will be the year that many automakers and even some motorcycle companies start offering small displacement 3-cylinder engines. The engineers have come up with good solutions to balance the vibration of firing four strokes of combustion on three cylinders. More importantly, turbocharging, variable valve timing and direct injection have finally come far enough to get real world usable power out of these small engines.
Nissan is documenting the construction of the Zero Emissions On-Demand Race Car (ZEOD RC) that’s scheduled to occupy the Garage 56 Technical Exhibition spot for the 2014 24-Hours of Le Mans. The last time we checked in with this car, Nissan had announced that it was going to be a pure battery electric vehicle and we discussed what it would take to make that happen. It seems that since that article was written, Nissan has come to the same conclusion as almost all of the other automakers trying to produce green supercars: hybrid is the way to go. The cost, weight and range of current battery technology is still not good enough to be the foundation of a performance oriented car. Electric power specs mentioned in the video are prefaced with “when running in pure electric mode” which probably means the ZEOD RC will be a series hybrid. I will update with more information as it becomes available.
In this first chapter of the ZEOD RC build, the Nissan engineers showcase the carbon fiber main tub. They talk about some of its unique features which mainly revolve around driver safety. Nine months is all the time that Nissan will have to complete the construction and testing of the car. Spaniard Lucas Ordóñez, the winner of the first Gran Turismo Academy competition, will be the ZEOD RC’s test driver. The official public debut is scheduled to occur at the World Endurance Championship race at Fuji Speedway with Michael Krumm behind the wheel. Lets hope the Deltawing based ZEOD RC will usher in a new era of green race cars. We will be following these build videos very closely.
Nissan announced at this year’s 24 Hours of Le Mans that they will be returning to the Garage 56 technological exhibition spot for 2014. Nissan was occupied the 2012 Garage 56 slot when they supplied the engine for the Deltawing project. This year was supposed to see the running of the GreeGT H2 hydrogen fuel cell car, but they weren’t able to complete the car in time and withdrew. 2014 will see the return of the Deltawing concept in the form of the ZEOD RC fully electric race car. The name stands for Zero Emissions On Demand – Race Car. The ZEOD RC is based off of a coupe version of the Deltawing developed before the entire program was absorbed by Nissan. The coupe should actually make a big improvement to the original Deltawing’s already exceptional aerodynamics.
Going endurance racing with a pure electric car is a pretty bold move on Nissan’s part. As with all electric cars, they’re going to face a huge challenge with storing enough energy with batteries. If I had to guess, I’d say they will go with a two-stage energy storage system. Electric drive in race conditions is very different from what most of us will see in street cars. Racing requires battery killing rapid discharges of power but also provides great opportunities for high torque regenerative braking. This constant cycle of extreme charging and discharging is the reason that the successful endurance racing hybrids from Audi, Toyota and Porsche use alternative quick discharge energy storage devices. Toyota uses an ultra-capacitor and the Audi and Porsche use a vacuum enclosed 40,000 rpm electromagnetic flywheel developed by Williams F1. Even though these devices are capable of reliable extreme charge and discharge rates, they hold a limited amount of total energy. I think the ZEOD RC will combine the current hybrid race car quick discharge tech with a bank of traditional batteries, most likely made with a similar chemistry to those used on street cars. These batteries have the highest energy density but don’t like charging and discharging at racing rates.
The two energy storage systems will work in tandem almost identically to how surge tanks/swirl pots work in a liquid fuel system. A swirl pot is a small intermediate fuel container added to cars that see a lot of lateral G-loading. Since its usually close to full, the fuel inside won’t slosh around during cornering and starve the high pressure fuel pump that feeds the engine. To keep the swirl pot topped off, it is fed with a low pressure pump from the main fuel tank which can now be made nice and roomy with plenty of fuel slosh since it no longer feeds the engine directly.
If you substitute electrical energy for the fuel in the swirl pot diagram, you can use the same energy pathways for what I think the ZEOD RC’s two-stage energy storage system will look like. The quick discharge portion is like the swirl pot in that it will be responsible for juggling the energy directly to and from the traction motor that drives the wheels and does the regenerative braking. Like the swirl pot, the quick discharge system can’t hold enough energy by itself. It will have to be replenished from the primary battery. Since the quick discharge system acts like a buffer for the power demands from the motor, the battery can discharge at a slower rate over a longer period of time just like how it only takes a low pressure pump to fill the swirl pot from the fuel tank in the diagram. Having the battery and quick discharge system working in tandem allows for the best of both worlds in terms of having a large amount of on-board energy while also being able to track the highly dynamic energy requirements of racing.
It was a great choice on Nissan’s part to adapt the Deltawing design to campaign an electric endurance racing car. Before the ZEOD RC, Nissan built a JGTC inspired, carbon fiber monocoque, mid-motor, rear wheel drive Nismo LEAF RC. Though interesting, the LEAF RC was more of a showcase of the potential of the LEAF motor and batteries. The body shape is still an adaptation of a street car and would not come close to the Deltawing’s aerodynamic efficiency. The original concept for the Deltawing was to have a car that could maintain expected race pace while using half the tires and fuel. Engineering the solution was extremely difficult, but the math is simple. Half the aerodynamic drag and half the weight of a regular car led to half the consumption. That brings us to the dilemma that all EV builders face: How much battery should they add to the ZEOD RC? There’s a break-even point where the weight of additional batteries adversely affects every aspect of dynamic performance. This effect is amplified in cars whose performance is based on lightweight agility, like the Deltawing. Given the current state of battery technology, Nissan is only going to be able to realistically add 2 or 3 laps of Le Mans worth of energy to the ZEOD RC before compromising the design concept. That’s OK, though. Quick recharging and/or battery pack swapping is a hurdle that will have to be tackled for electric car racing to be practical. Tesla has gotten their Model S pack swap down to around 90 seconds at their Supercharger Charging Stations. Surely Nissan can come up with something at least that good for Le Mans next year.
The Nissan Deltawing finally got a chance to prove itself two weeks ago coming in fifth at the Petit Le Mans at Road Atlanta. The car survived two collisions, one at Le Mans and one during practice for Petit Le Mans, before finally getting a chance to finish a race and showing the world what it could do.
The entire Deltawing concept has revolutionized how people think of race cars. The car has proven that it has competitive speed while using half the power, fuel and tires thanks to greatly reduced aerodynamic drag and a well thought out design. Now we get the privilege to see how it drives and to understand the engineering that makes it work up close thanks to Chris Harris and the DRIVE channel. Harris takes the car around Road Atlanta for 5 laps to get a feel for its character before having the its creator, Ben Bowlby, guide him through the suspension systems. They touch on a few interesting engineering concepts. Watch the video and we’ll talk about them afterwards.
Nissan recently announced that the experimental Deltawing race car will be making a return after being unceremoniously knocked out of its one-time exhibition in Le Mans. The car will be making another appearance in the Petit Le Mans series here in the US. Highcroft racing posted this on-board footage of some testing at Road Atlanta.