Tech’splaining: The Mini PHEV Powertrain

  • Jeff Sabatini has written for many publications over his 20 years in automotive journalism, including Car and Driver, the New York Times, the Wall Street Journal, and Sports Car Market magazine. His lifetime car churn includes 30 vehicles: eight GM cars, five Ford products, four Toyotas, three BMWs, two Jeeps, two Chrysler minivans, a Miata, a Mercedes, a Porsche, a Saab, a Subaru, and a Volkswagen.

can be reached at jeffsab@gmail.com
  • Jeff Sabatini has written for many publications over his 20 years in automotive journalism, including Car and Driver, the New York Times, the Wall Street Journal, and Sports Car Market magazine. His lifetime car churn includes 30 vehicles: eight GM cars, five Ford products, four Toyotas, three BMWs, two Jeeps, two Chrysler minivans, a Miata, a Mercedes, a Porsche, a Saab, a Subaru, and a Volkswagen.

can be reached at jeffsab@gmail.com
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Understanding how the Mini Cooper S E Countryman All4 works isn’t difficult. That’s because the Mini PHEV is actually quite a bit simpler than most plug-in hybrids.

  • The Mini Cooper S E Countryman All4 is a “through-the-road” hybrid with all-wheel drive.
  • An 87 horsepower electric motor turns the rear wheels.
  • A turbocharged, 1.5-liter 3-cylinder gasoline engine making 134 horsepower drives the front wheels through a six-speed automatic transmission.
  • Combined system output is 221 horsepower and 284 pound-feet of torque.
  • A 7.6 kW battery gives it 12 miles of all-electric range, according to the EPA.

Just as in other Minis, an internal combustion engine turns its front wheels. But the addition of an electric motor under the cargo compartment and a lithium-ion battery beneath the rear seat gives the electrified Countryman its hybrid abilities.

The Mini Cooper S E Countryman All4 has all-wheel-drive but no driveshaft to link its two separate powertrains.
The Mini Cooper S E Countryman All4 has all-wheel-drive but no driveshaft to link its two separate powertrains.

All The Wheels Drive

The powertrain layout of the Mini Cooper S E Countryman All4 allows it to do something few vehicles are capable of: switch between rear-wheel-drive, front-wheel-drive, and all-wheel-drive.

When the PHEV Countryman is running solely on electricity, it is functionally a rear-wheel-drive vehicle. The 87 horsepower electric motor drives only the rear wheels, with no physical driveshaft linking them to the ones in front. Those wheels are powered by a turbocharged, 1.5 liter 3-cylinder gasoline engine mated to a six-speed automatic transaxle. This is the same engine found in other Mini models, making the same 134 horsepower.

Yet the PHEV Countryman still has all-wheel-drive. Rather than using differentials or electronic clutches like typical all-wheel drive systems, the Countryman relies on signals from the car’s stability control system sensors to calculate when it should apply power to either of its separate powertrains. With the gas engine powering the vehicle, the rear electric motor can add power or work as a generator to send electricity back to the battery.

With both gas engine and electric motor able to deliver their full output at the same time, the Mini Cooper S E Countryman All4 has a combined output of 224 horsepower and 284 pound-feet of torque. That’s quite a lot—more than the gasoline-only version of the Cooper S Countryman. It uses a turbocharged, 2.0-liter four-cylinder engine rated at 189 horsepower and 207 pound-feet of torque.

Mini repurposes one of the Countryman's toggle switches to control its three electric drive modes.
Mini repurposes one of the Countryman’s toggle switches to control its three electric drive modes.

Three Modes

The Mini Cooper S E Countryman All4 has three operating modes: Max eDrive, Auto eDrive, and Save Battery. These can be selected via a toggle switch on the center stack.

To prioritize all-electric driving, select Max and the Mini Cooper S E Countryman All4 will keep its gasoline engine shut off—at least until one of three things happens. The first would be if battery charge drops below seven percent. The second is when speed exceeds 78 miles per hour. And the third condition is when the driver stomps on the gas pedal, demanding acceleration greater than can be provided by the 88-horsepower electric motor alone.

If any of these happens, the Countryman switches to Auto mode. This is the default, in which the Countryman operates as a hybrid, its gasoline engine and electric motor operating in tandem. The electric motor also handles regenerative braking. With sufficient battery charge, all-electric operation is still available up to 55 mph.

Save Battery mode does just what it says. It keeps the Countryman from going into extended all-electric operation, and insures that at least a 90 percent charge is maintained. (If the driver has selected Sport mode, charge is held at only 50 percent.) If Save mode is selected when the battery is below that threshold, the Mini will attempt to use the gasoline engine to charge the battery. This comes at the expense of fuel economy, as the rear electric motor creates additional drag on the vehicle when used in this way.

The plug-in Countryman retains its front-mounted gasoline engine and transmission, but adds a rear electric motor.
The plug-in Countryman retains its front-mounted gasoline engine and transmission, but adds a rear electric motor.

Range and Efficiency

The EPA says the 7.6 kWh battery in the PHEV Countryman is good for an all-electric range of 12 miles. Charging time at a Level 2 station (operating at 230 volts and 16 amps) is approximately 2.5 hours, according to Mini.

The EPA combined fuel economy rating is just 27 miles per gallon when the Countryman is running in hybrid mode. This low number is partially caused by the additional weight of the hybrid system. Mini lists the curb weight of the Cooper S E Countryman All4 at 3,948 pounds, which is 277 pounds more than the gasoline version.

This means that to truly save fuel with the PHEV Countryman, drivers will have to plan carefully and be sure to recharge often.


About the Author

  • Jeff Sabatini has written for many publications over his 20 years in automotive journalism, including Car and Driver, the New York Times, the Wall Street Journal, and Sports Car Market magazine. His lifetime car churn includes 30 vehicles: eight GM cars, five Ford products, four Toyotas, three BMWs, two Jeeps, two Chrysler minivans, a Miata, a Mercedes, a Porsche, a Saab, a Subaru, and a Volkswagen.

can be reached at jeffsab@gmail.com
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