REGENSBURG, Germany – Adding an electric component to a drivetrain can make a car with an internal combustion engine more efficient than any tweak the engine alone would produce. The benefit lower CO2 emissions and less fuel consumption can be experienced by the drivers directly, which is why fuel-saving 12-volt stop-start systems are so successful. These systems represent the entry level to electric vehicles. Of course, the higher the degree of electrification, the greater the gains in efficiency will be. Market penetration, however, has lagged expectations.
“There is a gap today between relatively affordable 12-volt start-stop systems and much more sophisticated hybrid solutions at voltages typically between 200 and 400 volts”, says José Avila, head of the Powertrain Division and member of Continental’s board of management. “By tailoring our electrical solutions, we are creating a modular system that allows automobile manufacturers to realize hybrids of varying degrees with voltage levels between 12 and 400 volts. Continental Powertrain is working very hard to provide systems and products with an attractive cost to benefit ratio for our customers and we think that the 48-volt system is such a solution supporting the customers aim to reduce CO2 at affordable costs”.
By tailoring our electrical solutions, we are creating a modular system that allows automobile manufacturers to realize hybrids of varying degrees with voltage levels between 12 and 400 volts. Image download
Continental beliefs that, as soon as OEMs have exhausted the potential of the existing 12-volt electrical systems, they will turn its attention to a secondary, supplementary 48-volt electrical system. The 48-volt system from Continental will permit several functions that currently are only offered in more complex 120-volt mild hybrids. Continental has implemented the proposed 48-volt architecture plus components in the innovative 48-volt Eco Drive test car.
The car features 48-volt components integrated as an optimized system solution: a belt-driven 48-volt starter generator that replaces a conventional generator, a belt tensioner with belts, a 48-volt lithium-ion battery from our battery specialist SK Continental E-motion, and a DC/DC converter that provides the link to the 12-volt electrical system. Among the advantages of the 48-volt Eco Drive are faster and quieter restarts – even at temperatures well below zero – and more efficient recuperation. This means that more current is available for energy-saving functions. “The main benefit is that the combustion engine can be shut off earlier and more frequently if it is not absolutely necessary to propel the car”, explains Xavier Pujol, head of the Hybrid Electric Vehicle business unit of the Powertrain division. “Through the use of sailing and coasting, the 48-volt system allows the engine more time out and it saves fuel”, Pujol continues. “Our “Eco Drive” also offers an advantage to automobile manufacturers as they do not have to change the configuration of the engine and the transmission. The technology can also be applied to smaller cars.”
An analysis of the current situation surrounding the electric drive train reveals that plug-in hybrids represent the most promising degree of hybridization next to 48 volts. Since it is possible to recharge plug-in-hybrids from the grid, a high-voltage battery is sufficient to go up to 50 kilometers purely on battery power. The combustion engine, on the other hand, still provides the full range of a conventional car, if that is needed.
“Our innovative plug-in hybrid shows that it is entirely possible to take an existing car with an efficient internal-combustion engine, retrofit it to make it a hybrid, and be able to drive 100 kilometers on just 1.5 liters of gasoline, depending on the driving cycle. Its CO2-emissions would be just 40 g/km”, says Christian Senger, head of automotive Systems & Technology at Continental.
Continental developed the plug-in architecture independently to include an externally excited synchronous motor developing peak power of 80 kW and 225 Nm of torque, supplemented by a claw clutch, built into the rear axle of the original car. This split-axle configuration means that this innovative vehicle features an all-wheel option that is permanently free of drag losses. This plug-in hybrid can go on electricity alone for 50 kilometers. According to Continental’s Mobility Study, 70% of all private cars in Europe and the USA drive fewer than 50 kilometers every day.
A purely electric vehicle (EV) remains the pinnacle of customized electrification (EV). A mass-produced car that Continental reworked into an electric car documents our expertise in purely electric vehicles. Around 40 of the company’s components that are specific to electric vehicles are built into this vehicle. Many of these components have been derived from components that Continental already has been supplying for a European electric vehicle. “Ultimately though, electrification is not just about propulsion. In order to achieve a breakthrough in e-mobility, we are going to need new cars that embody all of the advantages that an electrified drive-train architecture has to offer”, says Senger.
Those areas can range from driver-assistance systems based on camera and/or radar technology, through networking the car itself, to interior solutions that provide more comfort and convenience. Clever electronics can help allay customers’ misgivings about the range of an electric car. Continental’s new concept car “Simplify your Drive 4 Electric Vehicles” employs data from the navigation system and peripheral devices to calculate the remaining range. Drivers thus know whether their battery is charged sufficiently or whether they need to stop at a charging station en route.