TECH FOCUS: A plug-in hybrid version of the Renault E-Tech
Renault is currently launching the Clio on the market with the hybrid version of its E-Tech transmission, a remarkably innovative system presented in detail in our dossier "Renault E-Tech, an efficient and affordable full-hybrid transmission". The Captur will also go on sale before the summer, but this will be a plug-in hybrid version, and the Megane Estate will follow shortly afterward. A 9.8 kWh battery and charger are installed in the platform, the voltage has been increased to 400 V and a Sport Mode combines the power of the petrol engine and the two electric motors.
The Renault E-Tech system consists of a 4-speed transmission for the internal combustion engine and 2 speeds for the motor-generator, with no clutch or synchronizers.
It is worth noting that Renault developed the E-Tech system completely from scratch, in other words without the constraint of having to reuse existing components. The hybrid module is composed of a transmission with no clutch or synchronizers. There are 4 gears for the combustion engine and 2 gears for the motor-generator (MG). The E-Tech works in parallel or in series, in 100%-thermal or 100%-electric mode.
The transmission can be divided into 4 zones:
- In red, a 4-speed gearbox for the internal combustion engine (ICE) comprises an input shaft (input) and an intermediate shaft.
- In green, a 14 V starter-alternator (low-power electric machine) for starting the combustion engine, synchronizing the jaws of the 4-speed gearbox and potentially recharging the battery.
- In blue, the propulsion MG has 2 gears.
- In grey, a secondary shaft drives the final drive ratio and the differential.
The technical building blocks of the plug-in hybrid E-Tech
The Clio E-Tech has a 67 kW (91 hp) 1618 cm3 4-cylinder engine with a 4-cylinder motor-generator with up to 50 kW (68 hp) power capacity and can increase power in transient operation to a total of 103 kW (140 hp). The lithium-ion battery under the boot has a capacity of 1.2 kWh at 230 V.
The plug-in hybrid models have the same combustion engine and transmission as the basic Clio E-Tech. They feature a larger capacity lithium-ion battery - 7.2 kWh of a total of 9.8 kWh - which can be used to drive 50 km in electric mode according to WLTP measurement and up to 65 km over an urban cycle (WLTP City). The battery delivers a voltage of 400 V stored in 96 cells connected in series.
The plug-in hybrid versions can be connected to a terminal or to a 220 V network with a type 2 socket.
Since this is a plug-in rechargeble vehicle, we have an on-board charger. It has a maximum power of 3.5 kW of alternating current and can fully recharge the battery in about 2.5 hours and 30 minutes. The type 2 socket is located in the right rear fender and the charger is housed above the rear axle, to the right of the petrol tank.
The combined power of the plug-in hybrid models is 118 kW (160 hp), with the additional 20 hp provided by the electric motor, which no 400 V instead of 230 V. The increased electrical power, both from the battery and the motor, means the vehicle can be driven at up to 135 km/h without using the 4-cylinder engine. The liquid cooling of both machines is probably increased compared to the non plug-in hybrid version.
The Captur E-Tech Plug-In is WLTP-approved with fuel consumption of 1.5 l/100 km and CO2 emissions of 32 g/km, while the Megane Estate E-Tech plug-in has a fuel consumption of 1.3 l/100 km and less than 30 g/km of CO2/km (approval pending).
Platform modifications for the plug-in E-Tech
Layout of the battery and tank in the CMF-CD platform
The Renault-Nissan Common Module Family (CMF) modular platforms, CMF-B for the Clio and Captur and CMF-CD for the Megane, were designed from the outset to accommodate a 9.8 kWh battery weighing 105 kg. The reduced capacity petrol tank is set back and is located above the axle axis. The battery is positioned under the rear bench seat.
These 3 models have replaced the trailing-arm rear suspension and torsion beam with an independent wheel suspension which frees up more space between the wheels. This development explains why the Megane E-Tech plug-in sedan is being launched later.
The space in the Captur's interior remains the same as in the thermal versions and the rear bench seat still slides 16 cm. A space under the false floor allows the recharging cables to be stowed without any loss of boot storage capacity. The Megane Estate E-Tech plug-in retains its folding bench seat with flat floor.
Sport Mode available only in the plug-in version
When the driver selects Sport Mode and presses down all the way on the accelerator, the hybrid module combines the power of the petrol engine, the main 400 V motor-generator and the 14 V starter-alternator. In contrast, the non plug-in version uses the starter-alternator only to start the combustion engine, to synchronise the jaws of the 4-speed gearbox and potentially to recharge the battery.
Sport Mode boosts acceleration from 0 to 100 km/h by one second.
Using both electric machines in this situation is only possible in the plug-in version because of its battery power. Acceleration capacity then takes precedence over comfort and gear shifting is less muffled in favour of quicker gear changes. The starter-alternator provides torque up to 80 km/h and Sport Mode is no longer available if the battery charge level falls below 50% of its useful capacity.
Like its competitors, the E-Tech plug-in hybrid models have an "E-Save" function which avoids the use of the battery and thus maintains or retains a reserve charge (minimum 40% of the battery) for electric driving in specific situations, for example in city centres or zero-emission zones. The function can be selected using the button that replaces the "Stop & Start" button under the multimedia screen, while an EV button allows 100% electric driving.
The battery can be recharged in about 2.5 hours and 30 minutes from a 3.5 kW power supply.
Author: Yvonnick Gazeau
Source: Renault
