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Press release #Electrified mobility

From caravans to sports cars: Bosch extends the electrical car’s repertoire

cvt4ev

Continuously variable transmission (CVT) improves efficiency and performance

  • Smaller battery or greater range thanks to CVT
  • More torque when towing and driving off-road
  • Faster acceleration and higher maximum speeds
  • Continuously variable shifting for optimum comfort and convenience
Thorsten Schönfeld

Thorsten Schönfeld >

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Stuttgart, Germany/Tilburg, Netherlands – The electromobility business is booming. Certain applications, however, still pose enormous challenges for the electrical powertrain: when towing trailers, tackling steep ascents with a heavy load on board, or driving longer freeway stretches at high speed, the battery charge drops rapidly. Almost all electric cars have only one forward gear, but in such situations a multi-stage transmission can work more efficiently. To demonstrate this, Bosch installed a continuously variable automatic transmission (CVT) with push belt in a test vehicle. Called CVT4EV, this transmission increases efficiency by up to 4 percent. Depending on design, this can provide more torque in traction mode, better acceleration, or a higher maximum speed.

The CVT4EV expands the electrical car’s repertoire,

says Gert-Jan van Spijk, who is in charge of CVT engineering at Bosch.

“The CVT4EV expands the electrical car’s repertoire,” says Gert-Jan van Spijk, who is in charge of CVT engineering at Bosch. And because the transmission adjusts the ratio continuously without loss of traction, the driving ease typical of e vehicles is not lost. Bosch contributes its systems expertise plus several components to the complete CVT solutions offered by specialized transmission manufacturers.

Better performance, lower energy consumption

The CVT4EV’s variable gear ratio provides the best possible balance of efficiency and performance. To this end, the system can freely control the speed and torque of the electric motor. At low vehicle speeds, the downshifting capability of the CVT improves acceleration performance and gradeability. At higher vehicle speeds the upshifting capability enhances efficiency and increases top speed. In addition, it provides increased torque when towing and driving off-road, yet with lower energy consumption. Especially at constant speeds, the CVT4EV reduces the vehicle’s energy requirements.

Due to the electric motor’s reduced torque and speed requirements, a cheaper and more compact motor can deliver the same or even better performance. Alternatively, the same motor can achieve a greater range. As a result, manufacturers of electric vehicles can find the optimum balance between battery capacity and range.

High versatility, low complexity, reduced costs

This powertrain solution consists of a CVT4EV module, an inverter, an electric motor, and an axle drive with a ratio adapted to the vehicle. It is suitable for a wide variety of applications, from mid-size cars to sports cars to light commercial vehicles. Since individual software programs can often adapt the powertrains to the respective area of application, fewer hardware variants are needed. This cuts costs in both development and production. The use of CVT4EV also enables different driving modes for different types of vehicles, so carmakers can stand out from the competition by offering their brand’s typical handling in all their vehicle segments. As a result, end users get the driving experience they associate with the respective marque.

Compared to alternative variable solutions for electric vehicles, the CVT4EV offers a greater increase in the torque and engine speed available to the wheels. It also ensures completely smooth shifting without jolts – a must for electric vehicles. In addition, the larger spread of the CVT reduces the speed of the electric motor, resulting in an even smoother and quieter ride.

The concept of the CVT4EV with numerous Bosch components comes from Bosch Transmission Technology B.V., a Dutch subsidiary of Bosch. Based in Tilburg, the company is a leader in the development and mass production of CVT push belts. Full CVT4EV solutions are available through specialized transmission suppliers.

Mobility Solutions is the largest Bosch Group business sector. It generated sales of 42.1 billion euros in 2020, and thus contributed 59 percent of total sales from operations. This makes the Bosch Group one of the leading automotive suppliers. The Mobility Solutions business sector pursues a vision of mobility that is safe, sustainable, and exciting, and combines the group’s expertise in the domains of personalization, automation, electrification, and connectivity. For its customers, the outcome is integrated mobility solutions. The business sector’s main areas of activity are injection technology and powertrain peripherals for internal-combustion engines, diverse solutions for powertrain electrification, vehicle safety systems, driver-assistance and automated functions, technology for user-friendly infotainment as well as vehicle-to-vehicle and vehicle-to-infrastructure communication, repair-shop concepts, and technology and services for the automotive aftermarket. Bosch is synonymous with important automotive innovations, such as electronic engine management, the ESP anti-skid system, and common-rail diesel technology.

The Bosch Group is a leading global supplier of technology and services. It employs roughly 395,000 associates worldwide (as of December 31, 2020). The company generated sales of 71.5 billion euros in 2020. Its operations are divided into four business sectors: Mobility Solutions, Industrial Technology, Consumer Goods, and Energy and Building Technology. As a leading IoT provider, Bosch offers innovative solutions for smart homes, Industry 4.0, and connected mobility. Bosch is pursuing a vision of mobility that is sustainable, safe, and exciting. It uses its expertise in sensor technology, software, and services, as well as its own IoT cloud, to offer its customers connected, cross-domain solutions from a single source. The Bosch Group’s strategic objective is to facilitate connected living with products and solutions that either contain artificial intelligence (AI) or have been developed or manufactured with its help. Bosch improves quality of life worldwide with products and services that are innovative and spark enthusiasm. In short, Bosch creates technology that is “Invented for life.” The Bosch Group comprises Robert Bosch GmbH and its roughly 440 subsidiary and regional companies in some 60 countries. Including sales and service partners, Bosch’s global manufacturing, engineering, and sales network covers nearly every country in the world. With its more than 400 locations worldwide, the Bosch Group has been carbon neutral since the first quarter of 2020. The basis for the company’s future growth is its innovative strength. At 129 locations across the globe, Bosch employs some 73,000 associates in research and development, of which nearly 34,000 are software engineers.

Additional information is available online at www.bosch.com, www.iot.bosch.com, www.bosch-press.com, www.twitter.com/BoschPresse.

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