Hybrid cars are often thought of as a fairly recent development, but few things under the sun are truly new.
In response to the 1970s oil crises, engineers began contemplating ways to move the auto industry beyond fossil fuels, using much less sophisticated technology than what became available in the ensuing decades.
One of the leaders of this brief movement, it turns out, wasn't a car company.
It was an oil company.
The company built at least two hybrid prototypes, including a Cressida sedan for Toyota—about 20 years before the Japanese automaker delivered its first Prius hybrid.
1978 Toyota Cressida
Work was carried out by Exxon Enterprises Inc. (EEI), Exxon's venture-capital arm.
In an effort to diversify after the oil crises, EEI invested in solar and nuclear power, along with non-energy ventures, including fax machines and lasers.
Under its auspices, a group of engineers started Electric Vehicle Control Systems (ELVECS) in a corner of Exxon's research campus in Florham Park, New Jersey.
Its goal was to improve on the known technology of electric motors.
The group had first investigated all-electric vehicles, but the battery technology of the era was deemed inadequate.
Instead, they decided to develop a hybrid powertrain that used lead-acid batteries and a device called an "alternating current synthesizer" to convert DC current to AC for an electric motor.
Brochure for Exxon Chrysler Cordoba hybrid prototype
In 1978, engineers installed a prototype powertrain in a Chrysler Cordoba, known for advertisements featuring Ricardo Montalbán and "rich Corinthian leather."
They claimed the Cordoba hybrid got 27 mpg—hitting a target for 1985 models.
Exxon shopped the technology around to the Detroit Three automakers as well as Peugeot, but Toyota showed the only real interest.
In 1979, Exxon and Toyota signed a joint technology agreement, which led to the hybrid Cressida prototype.
That same year, though, Exxon began winding down its hybrid-car experiments.
2017 Toyota Prius
Shortly after the Toyota Cressida was delivered, Exxon began folding its automotive team into newly-acquired subsidiary Reliance Electric.
As the 1980s began, a change in management and new priorities led to a shift away from projects not related to oil.
Reliance was sold to an investor group in 1986.
Today, ExxonMobil remains publicly skeptical of electrified cars.
In its 2016 energy outlook, it estimated that by 2040, hybrids would comprise 40 percent of new-car sales—while battery-electric cars would make up just 10 percent.