Prius Prime Plug-In Hybrid Extends Driving Range

Toyota Motor Corp. expects its new Prius Prime plug-in hybrid sedan will have a U.S. fuel efficiency equivalency rating of 120 mpg when sales start there later this year.

At that level, the car would be the highest rated plug-in hybrid on the market and 26% more efficient than the previous Prius PHEV, which was discontinued two years ago. The new model has an overall driving range of 600 miles on a 11.3-gallon tank of gasoline. Although the vehicle’s all-electric range of 22 miles doubles that of its predecessor, critics point out that it still lags the range of several other plug-in hybrids.

The hybrid system teams Toyota’s 1.8-liter Atkinson-cycle 4-cylinder engine, which also is used in the standard Prius, with a new electric motor and an 8.8-kWh lithium-ion battery pack. The previous Prius PHEV had a 4.4-kWh battery.

Toyota says the Prime is the company’s first application of a dual motor/generator drive system, which uses both the electric motor and the generator to help boost acceleration.

Even when it isn't in hybrid mode, the vehicle automatically relies more heavily on its electric capability in situations where it is more efficient than using the engine, especially in urban and suburban driving and during shorter trips, Toyota says.

The Prime also benefits from a new exhaust gas recirculation system with a cooler, smaller, lighter and quieter hybrid water pump, according to the carmaker.

Buyers will get a smartphone app that allows them to remotely access and manage their car’s battery information, locate charging stations and compare fuel economy results with other Prius Prime owners.

Additional new features include advanced parking assist and Toyota’s Safety Sense P package. The so-called intelligent parking assist system uses ultrasonic wave sensors to precisely measure a parallel parking space and guide the vehicle into or out of it. A sonar sensor alerts drivers of the proximity to objects to the side in narrow passages. Safety Sense P bundles Toyota’s automatic emergency braking technology with adoptive cruise control and lane departure alert with steering assist.