Simply accelerating fast in a straight line is not enough for BMW

Jan 23, 2021

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When an ideal balance is called for between dynamics and ride comfort, the BMW 3 Series and 4 Series models consistently set the benchmark within their segments in the premium market. In terms of electrically powered vehicles, the new BMW i4 is set to take on this role very soon. The first purely electrically powered 4-door Gran Coupé enriches locally emission-free mobility with sheer driving pleasure.

“For the first time, we’ve developed a BMW with sporty DNA for purely electric driving entirely from scratch,” explains project manager David Alfredo Ferrufino Camacho. “The BMW i4 offers everything BMW stands for – and it’s fully electric, too.”

A few months prior to its world premiere, the BMW i4 is currently completing the final phase of driving dynamics testing. The focus here is on the integrated application of all drive and suspension components, ensuring that the spontaneous power delivery of the electric motor is combined with precisely controllable handling in every situation, fascinating cornering dynamics, optimised traction in all weather and road conditions and perfectly balanced ride comfort. For the purpose of this fine-tuning process, the BMW Group applies its technological expertise in the areas of drive and suspension drawn from decades of experience. This gives the new BMW i4 a mature premium character and makes for a driving experience that is unique within the competitive environment.

Excitingly calm: sprinting with the BMW i4.

With a maximum output of up to 390 kW/530 hp, the electric powertrain in the BMW i4 enables impressive acceleration manoeuvres: it reaches the 100 km/h mark in just four seconds from standstill. But even more impressive than its pure sprint capacity is the driving response it conveys. A model-specific damper technology reduces the dipping movements of the body at the moment of set-off, while the actuator-related wheel slip limitation (ARB) developed by BMW with its extremely fast and precise control guarantees optimum traction and perfect straight-line stability at all times – even on slippery road surfaces. This makes the catapult-like sprint in the new BMW i4 an experience that is both exciting and carefree, because it is not affected by drive slip or course corrections.

However, fascinating acceleration is only one aspect of the superior performance characteristics that define the BMW i4. Other distinguishing features include its spontaneous reactions to every movement – not just of the accelerator pedal but also of the steering and the brake pedal. The prerequisites for this high level of agility and precision are anchored in the underlying vehicle concept of the BMW i4. This includes the car’s long wheelbase, wide track widths, model-specific camber values, large wheels, as well as the high torsional rigidity and the vehicle’s low centre of gravity and weight balance.

Effortless precision: taking the bend on the ideal line.
All these parameters were taken into account in detail in the integrated application of the drive and suspension components so as to ensure hallmark BMW sporty flair in every situation on the road. The design and tuning of the suspension and damping systems consistently ensure optimum road contact. At the same time, the virtually silent drive in combination with the sophisticated suspension technology gives the impression of an effortlessly floating vehicle even at higher speeds, entirely unaffected by bumps in the road or difficult traction conditions.

“The BMW i4 conveys the feeling of being light and agile yet also solid and authoritative,” says project manager David Alfredo Ferrufino Camacho. “With its superior directional reliability and high level of cornering stability, it seems to literally attach itself to the road. All electric vehicles are capable of fast straight-line acceleration. But that’s not enough for us at BMW.”

The BMW i4 is also effortlessly controllable – even in highly dynamic driving situations. In addition to its neutral self-steering behaviour and its powerful, precisely controllable brakes, the steering in the BMW i4 is a major contributing factor here: it responds directly and with a high degree of accuracy, offering the driver precise feedback at all times while remaining entirely independent of drive forces, even during intensive acceleration or deceleration. Lane changes at high speeds are mastered with ease, while relaxed driving over long distances is ensured by the speed-related Servotronic power steering and the fact that the vehicle is largely insusceptible to any disruption caused by road bumps.

Typical BMW: the unique balance between sporty flair and ride comfort.
The distinctive driving dynamics of the BMW i4 derive partly from the fact that its performance characteristics are not achieved at the expense of driving comfort. The purely electrically powered Gran Coupé is characterised by unrestricted suitability for day-to-day use. Fitted with a high-voltage storage system featuring the latest battery cell technology that enables a range of up to 600 kilometres (WLTP), the chassis technology of the BMW i4 is designed for long-distance comfort, too. It is based on the high-quality damper technology, supplemented with model-specific components and separately tuned. This effectively reduces body vibrations due to road unevenness and on bends. The model-specific fine-tuning of the suspension and damping contributes significantly to the harmonious driving characteristics of the BMW i4.

At the same time as the final calibration runs are being held, preparations are underway for the production start-up at BMW Group Plant Munich. (See link to related press release.)
Here, every single production step is currently undergoing validation before the BMW i4 receives its final stamp of approval for characteristic BMW delivery quality.

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