Continental is electrifying
one diesel variant of both the new Renault Scénic and Grand Scénic models. The
system, offered as a "Hybrid Assist" uses a 48-volt hybrid drive in
production vehicles for the first time. The technology is a particularly
cost-efficient solution to significantly reduce fuel consumption and exhaust
emissions. Instead of the conventional starter generator, the system uses an
electric motor with a continuous output of six kilowatts (10kW temporary),
which drives the crankshaft of the engine via a belt. The electric motors with
integrated inverter are supplied from the Continental plant in Nuremberg.
Since 2013, Continental
engineers have been working together with Renault on a hybrid drive, which is
so cost-efficient to produce that it becomes an appealing option for mid-size
vehicles. To achieve this, the development partners have used low-voltage
hybrid technology, which operates at 48 volts. This is in contrast with the
considerably more expensive high-voltage technology, which operates at between
300 and 400 volts and is usually used in hybrid vehicles. However, the 48-volt
system facilitates significant savings. Therefore, with the mild-hybrid system,
Renault is aiming for combined fuel consumption of 3.5 litres of diesel per 100
km. They are also aiming to reduce the new Scénic´s CO2 emissions to 92 grams
per kilometre, which is a new CO2 benchmark in this vehicle class. This is
possible because the electric motor, operated as a generator, also converts a
large proportion of the braking energy into electricity, which is temporarily
stored in a small battery. This electricity can then be specifically used to
relieve the internal combustion engine. This is also the reason why nitrogen
oxide emissions and exhaust particles, especially in urban traffic, are reduced
when a 48-volt drive is combined with a diesel engine.
"We are proud that we
were able to secure Renault as the first customer for our innovative 48-volt
drive," said José Avila, Continental Executive Board Member responsible
for the Powertrain Division.
"Other production
launches for both diesel and gasoline vehicles are in the pipeline for Europe
and other markets including China and North America." According to
Continental, the market for 48-volt drives will experience significant growth
in the coming years. As Rudolf Stark, Head of the Hybrid Electric Vehicle
Business Unit, assumed, "in 2030, approximately one in four new vehicles
across the world will be equipped with a 48-volt drive," he added.
The 48-volt solution from
Continental is relatively easy to combine with preexisting internal combustion
engines, as it does not require any more room than a conventional starter
generator. This is due to the high power to size ratio of the electric motor,
which does not contain rare earth materials. This is achieved by water cooling
of the stator and the high efficiency of the induction motor. To save space,
the inverter, which is needed to convert direct current stored in the battery
into alternating current required for operation, is integrated in the housing
lid of the motor. The ready-to-install 48-volt drive is manufactured at the
Continental plant in Nuremberg, which already specialises in complex electronic
modules, such as those used for automatic transmissions.
In addition to designing the
48-volt drive for the crankshaft of the internal combustion engine in Renault
vehicles, Continental is also working on other solutions. The electric motor
can also be placed between the engine and transmission – allowing, for example,
purely electric driving in inner city areas.
Source: Continental