Tesla Roadster EV Production Model

Coming in 2007, 100% electric powered, Lotus Designed, 0-60 mph in 4 seconds

Tesla Motors, a Silicon Valley startup company, which was founded in June 2003 by engineers Martin Eberhard and Marc Tarpenning to create an efficient but nevertheless, sport electric car unveiled the Tesla Roadster production model which will go on sale in 2007.

Specifications: Underneath it’s sexy Lotus Elise inspired, body, the Roadster hides a powerful electric motor (185 KW) which promises to take it up 60 mph (96 km/h) from 0 in about 4 seconds while top speed is expected to exceed 130 mph (209 km/h). Despite its impressive performance, the 100% electric Tesla Roadster boasts a consumption that is equivalent to 135 mpg in a petrol car, which according to the company comes to 1 cent per mile. Range depends on driving style and conditions. On the EPA highway driving cycle is expected to reach 250 miles (402 km) on a single charge.

Available from 2007: Although prices haven’t been announced yet, Tesla say’s that for customers in Northern and Southern California, the cars will be available in the summer of 2007. Chicago will follow with a delivery date in the fall of 2007. The cars will then also be available in New York and Miami probably beginning in late 2007.

Developed, Designed & Assembled by Lotus: Components and subsystems for the car come from a variety of sources all over the world. Lotus Cars is assembling the Tesla Roadster under contract to Tesla Motors. Tesla Motors has also hired Lotus Engineering for certain design and engineering tasks. The Tesla Roadster style was developed in Lotus Engineering's design studio - Lotus Engineering won a design contest where several design firms submitted proposals. Lotus Engineering supplied the initial chassis which was significantly modified by Tesla Motors engineers. The company currently employs 80 people, including teams in California, the UK and Taiwan

Google & Pay-Pal: Tesla has managed to secure initial funding from prominent investors, such as PayPal co-founder Elon Musk, and Google co-founders Sergey Brin and Larry Page.

Press Release Technical Information

The Tesla Roadster powertrain consists of four main parts: the battery pack (called Energy Storage System or ESS), motor, a 2 spped transmission, and the PEM (Power Electronics Module), none of which are “off-the-shelf” components. Rather, each includes innovations, both small and large, to support our mission of a high-performance car that’s gentle on the environment.

Energy Storage System (ESS): The Tesla Roadster’s “fuel tank” weighs in at about 1,000 pounds and delivers four to five times the energy-density stores of other batteries. Safe, light, durable, and recyclable, it represents the biggest innovation in the Tesla Roadster and is one of the largest and most advanced lithium-ion battery packs in the world. Why this matters to you, the driver, is that it frees you to drive farther than ever before in an EV, while enjoying the power of world-class performance. The design ensures optimum operating conditions which maximize the life of the cells, while offering high levels of safety.

The architecture provides excellent redundancy and tolerance against cell-to-cell manufacturing variations. The system uses commodity lithium ion cells which, thanks to high demand by the consumer electronics industry, has spurred development that drives costs down and performance up. Finally, recharge time is impressively quick, enabled by an onboard, high-power charging system.

The system addresses thermal balancing with a liquid cooling circuit. Multiple passive and active safety devices ensure safe operation over the wide range of driving environments and scenarios. An array of sensors and a dozen microcontrollers communicate with the vehicle to allow efficient use and management of the battery pack. Finally, the entire assembly is housed in a rugged enclosure, which protects the system from the harsh road environment while supporting the internal components.

Motor: The motor for a high-performance electric car requires a device that is simultaneously light, compact, and high in efficiency. The Tesla Roadster EV motor is just that. We accomplish this by starting with a well-optimized electromagnetic design and then using the lowest loss conductors and the highest quality magnetic steel possible.

The power of the motor is not only limited by how much power you put into it, but also by how fast it can be cooled, how hot it can operate, and how efficiently it runs. We addressed each of these in innovative ways. Our motor can operate continuously around 120°C, thanks to the array of air-cooling fins on our aluminum housing.

The rotor is made with a proprietary process that produces a low resistance “squirrel cage” with large end rings using oxygen free copper. This allows the rotor to develop high current flows, and torque, with low resistance losses. The use of a small air gap allows tight inductive coupling which, combined with low loss magnetic materials, enables the development of high torque at high rpm. Together, these factors allow us to induce large currents, even at high rpm, producing much flatter power and efficiency curves from approximately 2,000 rpm to 12,000 rpm.

The sum of all these features is a single motor with efficiencies of 85 to 95 percent, power output of up to 185 kW, and a small footprint that measures just 250 mm (diameter) by 350 mm (length).

Transmission: Inside the box, our transmission couples the simplicity and efficiency of a manual with the smarts and sophistication of an automatic. The Tesla Roadster has only two forward gears and either one will work for most of your driving. Unlike a manual transmission, the car will not stall if you have it in the wrong gear. Plus it puts you in control of the shifting to fine-tune your driving experience or to achieve the upper limits of acceleration and top speed. And because there is no clutch, you can quickly and easily start from a stop or shift gears on the freeway.

Power Electronics Module (PEM): You’ll see this very important part of the car every time you pop the trunk. It controls over 200 kW of electrical power during peak acceleration, enough power to illuminate 2,000 incandescent lightbulbs (or 10,000 compact fluorescents). The PEM performs several critical functions in the Tesla Roadster, including motor torque control, regenerative braking control, and charging.

When you shift gears or accelerate in the Tesla Roadster, the PEM translates your commands into precisely timed voltages that tell the propulsion motor to respond with the proper speed and direction of rotation.

Circuits within the PEM monitor temperatures, voltages, and currents for maximum or minimum limits by using a combination of hardware- and firmware-settable values. These circuits prevent damage to the PEM, ESS, or motor when a variance from nominal operating conditions is detected.

During normal operation, the PEM monitors things like the voltage delivered by the ESS, the speed of rotation of the propulsion motor, and temperatures of the motor and power electronics. Should you like to know these things yourself, simply glance at the on-board Vehicle Display System.


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