AC Propulsion tzero

The tzero is a handmade electric sports car designed and built in very limited numbers by the U.S. company AC Propulsion in the early 2000s. It was the direct predecessor of the Tesla line of electric cars. The tzero was based on the Piontek Sportech kit car, which consists of a fiberglass body built over a reinforced steel space frame with double wishbone independent suspension and rack and pinion steering. AC Propulsion added the AC-150 drivetrain, a single-speed electric system with an overall gear ratio of 9:1.

Launched in January 1997, only three prototypes were built and plans for commercial production were dropped in mid-2003. The name comes from ''t''₀, the mathematical symbol for a starting point in time. Due to high production costs, AC Propulsion ceased to produce the tzero. Only three were built, and as of 2017 only 1 survived. The only remaining example is owned by the company itself.

Because the car recharges its batteries when the throttle is released slowing sharply as energy is recaptured it can be driven hard using only the accelerator pedal. Also, if the car detects a turn with more than half a ''g''-force (5 m/s²), it eases the rear-wheel regenerative braking to prevent slides.

Original lead–acid battery powered tzero

The original version of the roadster ran on 28 Johnson Controls Optima Yellow Top lead–acid batteries in series, which produced 150  kW (200 horsepower) and 177 lbs·ft (240 N·m) of torque at 336 volts and accelerated the car from a standstill to in 4.07 seconds. The single gear ratio limited the car's maximum speed to at 12,000 rpm, although it is said that early prototypes fitted with multiple gear ratios could hit . Even with the single ratio, lead–acid models are capable of completing a quarter mile (400 m) drag race in 13.24 seconds. The expected range per charge of the tzero with the lead–acid batteries is as a result of consuming only 180 watt hours (DC) per mile (112 Wh/ km) on the highway and due to regenerative braking. The car could be charged from 0 to 95% within an hour. The base price of this version was to have been US$80,000.

Lithium-ion battery conversion

Tom Gage was contacted by Martin Eberhard about the tZero car which Gage had built, and was currently converting to lithium batteries, similar to those that make up the battery packs of laptop computers. Gage stated that Eberhard had multiple "Schemes" and that he had to explain to Eberhard how unfeasible most of his concepts were. The conversion was done over six months from March through September, 2003 and gave the tzero a range. Lighter than the original version by , the lithium-ion conversion goes from in 3.6 seconds. The single gear ratio limits the car's maximum speed to just over at 13,000 rpm with proper gearing, though it has never been tested at greater than the electronic limit of . The base price of the car was US$220,000. Elon Musk and Martin Eberhard encouraged Tom Gage and Alan Cocconi to move the lithium-ion powered prototype into production. Eberhard then borrowed the converted tzero for three months and used it as a daily driver.

JB Straubel then told Elon Musk about the newly converted, now lithium-ion powered tzero and arranged a test drive. Musk also encouraged AC Propulsion to commercialize the vehicle. Tom Gage, however, again deferred in favor of working on their electrified Scion xB called the eBox. But he put Elon Musk in contact with Martin Eberhard which led to Elon Musk's Series A funding of Tesla Motors in April, 2004 and their hiring JB Straubel.

Long Ranger genset trailer

AC Propulsion also built a portable internal combustion powered generator mounted on a trailer known as the Long Ranger that can be towed behind the car and feed power to the batteries during travel. The trailer uses a 500 cc Kawasaki engine with a 9.5 U.S. gallon (40 liter) fuel tank and achieved in highway driving over at least . It is rated at DC output and can maintain . The trailer incorporates a novel "backtracking" feature that automatically steers the trailer wheels allowing even novice drivers to easily back a trailer through complex maneuvers; the company published a video demonstrating the ease with which the trailer could be backed through a set of slalom cones.

Production

, only one ''t_zero'' remains. Gruber Motor Company's car was destroyed in a building fire in May 2017.

See also

* La Jamais Contente
* Keio University Eliica
* Lightning GT
* Think Global AS
* Venturi Fétish
* Wrightspeed X1
* Aptera Motors

References

External links

{{Commons category, AC Propulsion tzero

Lots of Zoom, With Batteries
''The New York Times'', September 19, 2003

Automotive technologies
Electric sports cars
Electric concept cars
Production electric cars