Body and chassis
The i3 was the first mass production car with most of its internal structure and body made of carbon-fiber reinforced plastic (CFRP). BMW took advantage of the absence of a forward internal combustion engine, giving the i3 a "clean sheet design" with a sports-like appearance.[51][15][52]
The i3 includes four doors and seating for four occupants with rear clamshell doors.[15] The passenger compartment is known as the Life Module, made of CFRP, sitting atop the aluminum Drive Module, which incorporates the powertrain, frame, battery, and suspension. Carbon fiber is sourced from SGL Automotive Carbon Fibers, a joint venture of BMW and SGL Carbon in Moses Lake, Washington; the fibers are woven into fabric at another BMW/SGL joint venture plant in Wackersdorf, then the fabric is laid up into structures using a resin transfer molding process at BMW Landshut.[53] Finally, the finished pieces are assembled into the Life Module by 173 robots at BMW Leipzig, using adhesives only.[54]
The door panels of the i3 are made of hemp, which mixed with plastic helps lower the weight of each panel by about 10%. Hemp fibers, left exposed, also form a design element of the car's interior and contribute to sustainability. Further environmental consciousness is reflected in the optional seat leather, which is tanned with olive-leaf extract and the dashboard trim, which is made from environmentally refined wood from certified cultivation in Europe.[55] By November 2010, BMW had demonstrated the passenger compartment's light weight, and the automaker's chief executive said they had already decided on the basic design of the car and that road-testing prototypes began soon after.
The tires for the i3 were designed by Bridgestone to minimize rolling resistance and aerodynamic drag, featuring a narrower width, larger diameter, and higher inflation pressure (155/70R19 at 320 kPa) than typical passenger car tires (175/65R15 at 210 kPa for equivalent load capacity).[56] Bridgestone call this combination of changes "ologic", supplying similar tires to World Solar Challenge teams.[57][58]
At launch Bridgestone were the sole tyre supplier for the BMW i3, but since launch Nankang, Continental and recently Michelin have begun to supply 155 and 175 widths.[59]
Powertrain
The i3 uses a unique powertrain consisting of a 125kW (168hp) synchronous permanent magnet electric motor powered by lithium-ion batteries and driving the rear axle.[15] The top speed is limited to 93 mph.[61] A range-extender option is available, adding a small rear-mounted 647cc petrol engine from a BMW motorcycle to recharge the high voltage battery when it is low on power.
Battery, range, and economy
BMW aimed to achieve a range of 100 mi, the same range that was expected for the BMW ActiveE, but in order to reduce weight, battery capacity was cut to 16 kWh instead of the ActiveE's 30 kWh.[62] As initially sold (2014–16 model years), the vehicle's official range is 80 to 100 mi for the 60 Ah battery option under the New European Driving Cycle (NEDC), and up to 200 km in the most efficient driving mode.[6][63] Under the United States Environmental Protection Agency (EPA) cycle, the official range of the 60 Ah model is 81 mi with combined fuel economy of 124 miles per gallon gasoline equivalent —MPGe— (1.90 L/100 km; 149 mpg imp).
The 2014–16 model years with the range extender option have an official NEDC total range of 160 to 186 mi.[64]
The battery is lithium ion using nickel manganese cobalt (NMC) chemistry with a peak output of 139kW (for 10 seconds), peak
Charging
BMW designed the i3 eDrive powertrain based on the premise that the battery would need to be recharged only once every two to three days. The charging frequency was derived from field trial results taken from the BMW ActiveE and MINI E vehicles in Asia, Europe and the U.S., whereby the typical commuting use between the pilot users' homes and workplaces was calculated.
The i3 allows the owner to charge the battery from a conventional wall socket. In addition, the BMW i3 has multiple charging options. With the original 60Ah battery, AC fast charging can take less than 3 hours when charging from 0 to 80% while using the BMW i Wallbox Pure or any 3rd party charging equipment (EVSE) supporting 32A. Most European models supported three-phase AC charging up to 11 kW. The i3 also has a 50 kW DC fast charging option suitable for public DC charging stations, which can take less than 30 minutes to charge the 60Ah version from 0% to 80%.[87][88][89] Later 94Ah and 120Ah models take proportionally longer.
In the US, the i3 can also be charged from any public charging station with an SAE J1772 connector.[90]
Additional mobility
BMW i introduced the BMW i Flexible Mobility Program for trips where the range of a BMW i3 would not be enough to allow customers to cover longer distances, such as providing a conventional BMW vehicle for a specified number of days per year.[94] The program started in October 2014 in the US and individual dealers can choose whether to participate in this program.[95] BMW is also offering a roadside assistance program in areas of high sales. The assistance vehicle will provide a charge so the i3 can travel to the next charging station. In addition, the i3 digital display panel shows the location of nearby recharging stations to alleviate range anxiety.[96]
Range extender option (i3 REx)
An optional petrol/gasoline range extender engine is marketed as REx[15] and is powered by the same Kymco-built 647 cc inline two-cylinder engine used in the BMW C650 GT maxi-scooter.[97] The system is intended as an emergency backup to extend range to the next recharging location, and not for long-distance travel.[98] The 647 cc engine as fitted in the i3 REx is derated compared to the engine of the same displacement in the C650 GT; the REx engine develops 25 kW and 55 Nm at 4,300 RPM, achieving compliance with Euro-6 emissions standards[99] compared to the 44 kW (at 7,500 RPM) and 66 Nm (at 6,000 RPM) for the engine in the C650 GT, which complies with the less restrictive Euro-4 emissions.[100]
United States / California regulation
The range-extender option of the BMW i3 was designed to meet the California Air Resources Board (CARB) regulation for an auxiliary power unit (APU). According to rules adopted in March 2012 by CARB, the 2014 BMW i3 with a REx unit fitted is the first car ever to qualify as a range-extended battery-electric vehicle or "BEVx". CARB describes this type of electric vehicle as "a relatively high-electric range battery-electric vehicle (BEV) to which an APU is added." The unit, which maintains battery charge at about 30% after the pack has been depleted in normal use, is strictly limited in the additional range it can provide. As a BEVx, the car is required to deliver a minimum 75 mi electric range.[106]
CARB classified the i3 with the REx option as a "Transitional Zero Emission Vehicle" (TZEV), the same classification as other plug-in hybrids such as the Chevrolet Volt and the Toyota Prius Plug-in Hybrid. This classification made the i3 REx eligible for California's green sticker that identifies the vehicles allowed to be operated by a single occupant in California's high-occupancy vehicle lanes (HOV), or carpool or diamond lanes, but not for the white sticker reserved for pure electric cars, such as the BMW i3 without REx.[107][108] In addition, CARB certification of the i3 REx as BEVx allows the i3 with range extender to be eligible for a US$2,500
Interior and controls
In June 2012 an updated version of the BMW i3 concept car was unveiled at the opening of the first BMW i store, located on Park Lane in London, UK. The updated i3 concept consists of a new interior colour and materials concept. The seat covers combine responsibly sourced wool and leather naturally tanned with an olive oil leaf-based agent. The almost symmetrical curving dash is inlaid with treated eucalyptus wood that, according to BMW, is sourced from sustainably managed European forests.
Information is provided to the driver through a 16.5 cm freestanding instrument cluster and a 22.3 cm central information display. The bench-derived front seats replace the center tunnel that bisected the cabin and a floor-mounted transmission, brake levers or center console are also absent.[111][112]
The BMW i3 has two pedals like all cars with automatic transmission. The accelerator pedal acts as both accelerator and engine brake. When the driver releases the pedal, the vehicle's kinetic energy is regenerated by the vehicle drivetrain to recharge the battery. This has the effect of slowing the car down. During the field testing of the Mini E, which has an accelerator that recharges the battery in this way, and consists of brakes that only apply to the rear wheels, BMW has learned that drivers tend to rely on the engine brake: around 75% of all deceleration maneuvers are initiated without the brake pedal in urban traffic areas.
Operating modes
The BMW i3 allows the driver to select the car energy consumption through three different driving modes: Comfort, Eco Pro or Eco Pro+ mode. In the standard Comfort mode the i3 delivers a range between 80 and 100 mi in everyday driving conditions, while the i3 REx delivers between 160 and 180 mi.[114][115] The Eco Pro mode increases the driving range by around 12% through a different accelerator pedal mapping which uses less power. In Eco Pro+ mode, all settings are geared to achieving the maximum possible range, increasing the driving range by about 24% compared with Comfort mode. In this mode, the maximum speed of the BMW i3 is limited to 90 km/h and electrical devices such as the heating and air conditioning are switched to energy-saving mode.[114][115][116][117] The i3s, introduced for the 2018 model year, adds a SPORT drive mode.
Safety
The European New Car Assessment Programme (Euro NCAP) awarded the i3 a four-star car safety rating, resulting in the following ratings for each criterion:
The BMW i3's overall ratings are lower than the other six best-selling plug-in electric vehicles, the Volvo V60 Plug-in Hybrid, Renault Zoe, Nissan Leaf, Mitsubishi Outlander P-HEV, Chevrolet Volt and Opel Ampera, all of which were rated five stars.[119]
