Techrules has shown the final production design of its first series hybrid supercar at the Geneva Motor Show.
‘Ren’ is the first production vehicle from the China-based automotive research and development company, and features its proprietary Turbine-Recharging Electric Vehicle (TREV) technology.
The aerospace-inspired design is by Fabrizio and Giorgetto Giugiaro. The Ren features a lightweight chassis allows the car to be configured with one, two or three polycarbonate canopies: one for track use by only the driver, two for the ‘Le Mans’ configuration with a single passenger, or three to accommodate the driver and two passengers.
Ren is the world’s first electric production supercar to feature the ground-breaking Techrules-developed Turbine-Recharging Electric Vehicle (TREV) series hybrid powertrain.
A variety of configurations will be available to tailor the powertrain to the exact requirements of the customer. The flagship version – with a battery capacity of 25 kWh and with two motors at the front and four at the rear – delivers maximum power of 960kW (1,287 hp/1,305 ps) with a range of 1,170 km from 80 litres of diesel fuel (NEDC).
Beyond the Ren, the innovative powertrain and platform concept will support family and city cars, with the potential for many more model variations.
The Techrules Ren will be the first supercar from a Chinese manufacturer and the world’s first electric production supercar powered by a turbine range extender system. The Ren can be classed as a range extended electric vehicle with a distributed powertrain (multiple electric motors). A pure plug-in electric version will also be available in the future.
The Techrules patent-protected series hybrid powertrain combines extensive experience of aerospace and electric vehicle technologies with several proprietary technical innovations to deliver unprecedented levels of efficiency and performance, and ultra-low environmental impact.
Techrules first presented its Turbine-Recharging Electric Vehicle (TREV) system at the 2016 Geneva Motor Show, introducing an all-new range extender system that uses a turbine to drive a generator which charges the battery pack. This in turn, provides electricity to drive the traction motors. Unlike many previously developed turbine powertrain systems, there is no direct electrical feed from the generator to the electric motors in normal operation. Only when the battery is depleted can the turbine be used to propel the car.
Air drawn into the micro turbine is passed through a heat exchanger where heat from the exhaust air is transferred to the cold intake air, and compressed before it is ignited. Ignition of the compressed and heated fuel-air mixture generates enormous energy which is channelled at very high speeds to turn the turbine vanes. As this hot exhaust gas is expelled, it passes through the heat exchanger to ensure the heat energy is recuperated and transferred to cold intake air.
Techrules Chief Technology Officer, Matthew Jin, explains: “In the conventional cars that dominated the 20th century, the combustion engine that converts a fuel’s chemical energy into a useful mechanical energy is also the driving engine that turns the wheels.
“Because turbines have always been a very inefficient way to convert chemical energy into useful, wheel-turning mechanical energy, only a few have tried to use a turbine in the powertrain system, and none have ever succeeded commercially.
“But, with electric vehicles, an electric motor is used to drive the wheels, which effectively frees the combustion engine to exclusively convert chemical energy into mechanical energy and finally into electric energy. This is a major breakthrough, making it possible for us to use the highly efficient turbine engine as a superb range extender on our vehicles.”
The second generation of Techrules’ unique TREV (Turbine-Recharging Electric Vehicle) will power the Ren, with the option of one or two turbines installed to power the batteries. Two types of turbine are available, a 30 kW high efficiency unit and a high power density 80 kW unit, with the variety of combinations offering a wide range of overall turbine power and efficiency options. The new generation turbine – which is in advanced stages of productionisation – is smaller and lighter and runs at higher speeds than previous versions.
The TREV system still has the potential to deliver 2,000 km from 80-litres of fuel, depending on the vehicle it is used in. The EV-only range is targeted at 200 km, subject to the battery and electric motor configuration specified.
The TREV system can be run on both liquid and gaseous fuels. In testing, diesel has proven to provide the best performance capabilities, with emissions better than the EU6 standard for diesel.
In the future, liquefied natural gas or hydrogen will be the most environmentally efficient fuels, the latter of which will generate zero tailpipe emissions. The TREV system is scalable and designed to be manufactured in high volumes to power any class of car – and could even be made small enough for a motorcycle.
The drivetrain comprises two, four or six axial flux, liquid-cooled electric motors manufactured by YASA in the UK. These motors, known as ‘pancake motors’, have a large diameter in relation to their length, making them ideal for use on the Ren as the motors package flat against the inside of the carbon tub, where space is at a premium.
The rear-wheel-drive two-motor configuration will see a motor driving each rear wheel. A four-motor set-up will drive all four wheels. The highest-power six-motor configuration has two motors for each rear wheel, and one for each front wheel.
The motors drive each wheel via a reduction gear of 1:3.3 housed in each side plate specially designed for the car.
As with the platform, the Ren’s powertrain is also modular, comprising either two, four or six axial flux (biscuit tin) YASA electric motor generators. There are also three available battery capacities: 14 kWh, 25 kWh, and 32 kWh. And customers can choose from either one or two high efficiency 30 kW turbine configuration, or a high power density two-80 kW turbine set-up.
The battery pack is designed and manufactured by Podium Engineering specifically for the Ren. It will come in three capacities of 14 kWh, 25 kWh and 32 kWh and can be charged to 80% capacity in under 15 minutes using a DC fast charger. The target lifespan of the battery is 100,000 cycles.
The batteries feature an innovative design and incorporate battery management technologies that enable superior charging efficiency and power balancing between battery cells. Each cell voltage and temperature are independently monitored. Cells are connected via a circuit board instead of wires, for greater durability. The number of cells is 1,344 cell for the 25 kWh version and the pack can deliver 1,200 A, enough to drive six wheel motors at full power.
The battery management system (BMS) is integrated and designed to optimise the performance and life of the battery while ensuring absolute safety. There are three water cooling circuits for the motors, battery and inverter. A heat exchanger (radiator) pack is attached to the front aluminium chassis plate and the cooling circuits are supplied by three electric pumps also mounted on the front plate.
The performance and range capabilities of the TREV system are directly linked to the chosen modular options and electric drivetrain configurations.
Altogether, the new Techrules platform can cater for more than 300 TREV system options.
With a future range of models in mind the Ren represents a platform that can be modulated to support supercars, SUVs, family sedans and even small city cars. However the manufacturing approach will be different across the categories. The supercar construction is introduced in the Ren supercar, with a hand-crafted carbon-fibre tub and double wishbone suspension following the high level performance focus of formula and sports racing cars. This approach is only suitable for very low production volumes.
Techrules is taking this unique approach to developing platforms to allow models to therefore share similar powertrains but within different vehicle architecture.
Production of Ren is likely to start in 2018, with orders starting at the 2017 Geneva Motor Show. A limited run of 96 track versions will be hand built in Italy, with a projected production volume of 10 cars per year.