2013 Honda Fit EV: Powertrain

Honda's development of battery-electric automotive powertrains dates back to 1988, with the early research on the car that would eventually become the EV Plus. Since then, Honda has developed and marketed a range of hybrid vehicles that feature electric assist, as well as the FCX Clarity fuel-cell vehicle, which is propelled solely by an electric motor.

The 2013 Fit EV builds on nearly a quarter century of Honda electric vehicle engineering, and is designed to meet the needs of a typical urban commuter with a combination of responsive power, uncannily smooth operation and exceptionally economical operation. The 2013 Honda Fit EV boasts a world-leading energy efficiency of 29kWh per 100miles, and a gasoline miles per gallon equivalent of 118 MPGe (combined city/highway, adjusted). Offering an EPA-certified unadjusted driving range of 132 miles on a single charge using the U.S. EPA city cycle test methods, the adjusted combined city/highway EV range posted on the new Fuel Economy label is 82 miles.1 This range makes the Fit EV ideal for local driving and even medium-range daily commuting.

The Fit EV is powered by a 20-kilowatt hour (kWh) lithium-ion (Li-Ion) battery and a 92-kilowatt (kW) coaxial electric motor/gearbox. The high-density electric motor, which is similar to the unit that drives the FCX Clarity fuel cell electric vehicle, delivers excellent efficiency and power while remaining quiet at higher speeds. Off-the-line response and acceleration times are comparable to those of a 2.0-liter or larger internal-combustion vehicle of similar physical size.

Several innovative features, including a 3-Mode Drive System adapted from the CR-Z Sport Hybrid, help the driver maximize the driving range of the Fit EV. The system allows the driver to select between SPORT, NORMAL and ECON to instantly change the driving experience. In SPORT mode, quick acceleration adds to the Fit EV's fun-to-drive nature. While in ECON mode, practical driving range can increase compared to driving in NORMAL mode.

In addition to the 3-Mode Drive System, other energy-saving features include a new regenerative braking system and a highly efficient all-electric climate control system.

The 6.6 kW onboard 32-amp charger allows for convenient recharging of the Fit EV with a 240-volt circuit in less than three hours2. Honda has partnered with Leviton as the preferred Electric Vehicle Supply Equipment (EVSE) charging supplier so that owners can easily equip their home with a 240-volt charging station. When using a 120-volt household current, a full recharge takes under 15 hours 2.

The nearly maintenance-free Fit EV powertrain is highly advanced, yet it's designed to be easy to operate day in and out. Special instrumentation provides clear and concise information to the driver on power usage, state of charge and predicted driving range. To allow charging in the overnight hours when power companies charge the lowest rates, the Fit EV includes charge scheduling that can be set via the Multi-Information Display (MID). An available free Fit EV smartphone app offers remote charge scheduling and many other features. Charging can also be initiated via an interactive remote control with a range of up to 100 feet (See Interior section for more information).

  • Coaxial electric motor/gearbox
  • High output, high efficiency, compact construction
  • 92-kW (123 horsepower) output
  • 256Nm motor torque (189 ft-lb)
  • Single forward ratio
  • Advanced Lithium-ion battery
  • Energy capacity: 20kWh
    • Superior performance envelop including long life expectancy, superior safety and high energy recovery capability
    • Further durability-enhancing battery cooling system
  • Charging system
  • 6.6kW on-board charger
  • Less than 3-hour charge time2 with 240-volt supply (under certain conditions)
  • Less than 15-hour charge time2 with 120-volt supply
  • Leviton-brand Electric Vehicle Supply Equipment (EVSE)

 

Electric Drive Motor
Fit EV's Honda-designed AC synchronous electric motor is similar to the unit that drives the FCX Clarity fuel cell electric vehicle. The drive motor configuration was developed to deliver powerful acceleration and high rpm capability, along with very quiet operation. To minimize noise and vibration, the rigidity of the Fit EV's motor housing has been increased, as compared to that of the FCX Clarity.

The Fit EV's rotor and stator feature a combined reluctance-torque, low-loss magnetic circuit and full-range, full-digital vector control to achieve high efficiency and high output over a wide speed range. The innovative shape and layout of the magnets in the rotor results in high-output, high-torque, high-rpm performance. These innovations deliver a maximum output of 92 kW. Average motor efficiency in EPA city driving test cycle is a very high 94.6%.

Coaxial Gearbox

As in the FCX Clarity, the Fit EV's motor rotor shaft features a hollow construction, with the driveshaft passing through the center in a coaxial configuration. This arrangement allows the motor and gearbox to be combined into a single compact unit, while providing efficient transmission of the motor's high-output, high-rpm power to the driveshaft. Fewer rotor oil seals result in lower friction for higher transmission efficiency.

Interior Permanent Magnet (IPM) Rotor
The electric motor's rotor features an Interior Permanent Magnet (IPM) to lower inductance, improving reluctance torque and delivering high-torque performance. The magnet's high-energy characteristics also contribute to high torque and a compact design. Compared to the rotor designs in the EV Plus and FCX Clarity, the shape of the magnet in the Fit EV rotor has been optimized to increase energy conversion efficiency.

Power Control Unit
A Power Control Unit (PCU) is located in the front of the vehicle, just above the electric motor. The Honda-designed PCU controls the total operation of the Fit EV's electric powertrain, including regenerative braking and recharging functions.

Li-Ion Battery
A Toshiba-produced 20 kWh lithium-ion (Li-Ion) battery provides the Fit EV with superior performance envelop including long life expectancy, superior safety and high energy recovery capability. It is placed under the passenger compartment to optimize weight distribution, provide a lower center of gravity and enhance handling. The battery is air-cooled for high output and further increased durability. The Fit EV's lithium-ion battery technology has approximately twice the energy density of conventional nickel-metal-hydride batteries.

3-Mode Drive System

The Fit EV's 3-Mode Drive System allows the driver to select between individual modes of performance for SPORT, NORMAL and ECON driving styles. The system is activated via three backlit buttons on the dashboard to the left of the steering wheel. The electric motor power typically available is different in each mode.

SPORT Mode
SPORT mode enhances multiple vehicle systems for performance including the motor responsiveness. The ambient meter and mode indicator around the EV display illuminate in red when the vehicle is in SPORT mode. The "power" side of the power/charge gauge also extends further when in SPORT mode.

Pushing the SPORT mode button influences the following systems (compared to Normal Mode):

  • Maximum of 92 kW of electrical power available during acceleration, a feeling is similar to 3.0-liter gasoline engine at half-throttle.
  • Approximately 10-percent reduction in cruising range compared to Normal mode
  • Accelerator pedal action optimized for enhanced acceleration feel
  • Air-conditioning system operates normally
  • EV range in this mode is continuously calculated and displayed

NORMAL Mode
NORMAL mode provides standard settings for steering, electric motor power and air conditioning. The mode indicator around the EV display illuminates white when the vehicle is in NORMAL mode. At startup the vehicle will default to Normal mode if the vehicle was previously driven in Sport mode.

Pushing the NORMAL button influences the following systems:

  • 75 kW of electrical power available during acceleration, a feeling is similar to 2.0- to 2.4-liter gasoline engine at half-throttle.
  • Accelerator pedal action optimized for linear acceleration feel
  • Air-conditioning system operates normally
  • EV range in this mode is continuously calculated and displayed

ECON Mode
During ECON mode operation, the electric motor's responsiveness is tuned for optimal efficiency and the air conditioning system can reduce its overall load on the battery. The mode indicator around the EV display illuminates green when the vehicle is in ECON mode.

Pushing the ECON button initiates a range of functions that increase energy efficiency:

  • 47 kW of electrical power available during acceleration (increased to 75kW during full throttle)
  • Accelerator pedal action promoting  an energy efficient driving style (including gliding feature during accelerator off)
  • Reduced automatic climate control blower fan speed and minimized A/C compressor/electric heater engagement whenever possible
  • Cruise control uses less motor power when possible
  • EV range in this mode is continuously calculated and displayed

Regenerative Brake System
The Fit EV turns kinetic energy into electrical energy via a regenerative braking system, and this captured energy is then stored in the rechargeable Li-Ion battery pack. The electric motor acts as a generator that can recharge the battery pack during braking, gentle deceleration or coasting. The Fit EV's regenerative braking system intelligently apportions braking power between the hydraulic brakes and the electric motor to extract electricity from the vehicle's kinetic energy. When selecting the B shift position, regenerative braking is further increased.

Transmission Selector
A fixed gear ratio allows for simple operation, with an easy-operating shift control used for forward, reverse and park offering a light touch and a short stroke. In addition to the normal "D" (Drive) position, the selector also has a "B" (Brake) position. When shifted to the B position, regenerative braking is increased. This is useful when controlling the Fit EV's following distance behind a car ahead, or when controlling speed on a downhill.

Variable Energy Regeneration in Downhill Driving
To reduce the need for repeated brake-pedal operation in downhill driving, the Fit EV's regenerative braking system automatically increases regeneration to help limit vehicle speed. Assessing downhill incline and vehicle speed, the system regulates speed when the driver first releases the accelerator pedal, minimizing the need for frequent braking. The system also adjusts the regenerative braking function to help maintain constant vehicle speed after the driver initiates brake-pedal inputs. The function is similar to engine braking in a gasoline-engine powered vehicle, but more intelligent, smoother, and easier to use.

Charging
The Fit EV uses the standardized SAE J1772 charging port, which is accessed via a lockable lid on the left front fender just above the wheel. When connected to a standard 120-volt AC wall outlet with the included portable charging cable, the Fit EV can be fully recharged in less than 15 hours1*. With a 240-volt AC Level 2 Electric Vehicle Supply Equipment (EVSE) device connected to the Fit EV's standard onboard 6.6-kW charger, the charge time is less than three hours1*. This extremely short recharge time allows the Fit EV to be completely recharged during the early morning "super off-peak" hours where in some areas electricity rates are lowest. It also allows the Fit EV to be plugged in for a short period of time for a partial recharge. A 14-percent recovery in battery state of charge is possible in 30 minutes using a 240-volt AC Level 2 supply – double the recovery state of most competing models.

Home Charging Station
At Fit EV launch, Honda has selected Leviton as the preferred Electric Vehicle Supply Equipment (EVSE) charging station available for customer purchase. The Fit EV's state of charge may be monitored and remotely controlled (within 100 feet) through the use of a supplied interactive remote, or from farther away with an available smartphone application.

Telematics and Interactive Remote Control
Standard telematics allows the driver to manage the electric-vehicle ownership experience by staying connected through a smartphone, personal computer or interactive remote control. Through the available free Fit EV smartphone and computer applications, the driver can remotely view the vehicle's state of charge, initiate charging and activate the air conditioning and heater to pre-condition the vehicle while it is still connected to the grid, thus maximizing battery range on start-up. The mobile application and website also offers the ability to set charging notifications and alerts to optimize charging times based on varying utility rates, and provides access to 24-hour roadside assistance. The Fit EV is equipped with a standard Honda Satellite-Linked Navigation System™ that offers the ability to locate public charging stations and features FM traffic that provides frequently updated traffic information.

The Fit EV's standard interactive remote allows the driver to monitor the vehicle's state of charge and cabin temperature. Additionally, the driver can initiate and terminate charging and remotely turn the climate control on or off using the interactive remote. The interactive remote does not require an internet or mobile connection to operate; the driver must only be within 100 feet (30 meters) of the vehicle. (See Interior section for more information.)

12-Volt Electrical System

Like a conventional gasoline powered vehicle, the Fit EV has a 12-volt electrical system and battery to operate typical items like lighting, climate control, audio system and many other features. The main lithium-ion powertrain battery charges the 12-volt battery through an on-board DC/DC converter.

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