Platform Sharing: BMW Cluster Architecture

Like many automakers, BMW car has committed to electrifying a key aspect of its product portfolio over the next 10-15 years.

But BMW has only committed to ensuring 50% of its car sales are fully electric by 2030, even as Mercedes-Benz says it will only sell electric vehicles by 2030 – at least. where market conditions permitgiving them opportunities in markets where the necessary infrastructure is not available.

Likewise, Audi says it will stop making internal combustion engines by 2033 as part of its Vorsprung 2030 strategy, although it may continue to offer them in China after this date.

Other premium brands like Volvo and Cadillac have already set their combustion output cuts for 2030, which makes BMW even more cautious.

BMW’s decisions on electrification are part of a broader ‘Power of Choice’ strategy, where the Bavarian brand has committed to introduce electrified versions of every vehicle in the range while retaining internal combustion engine alternatives.

The company argues that, as many powertrain solutions will continue to exist for the foreseeable future, it should be prudent to allow customers to choose the option that best suits their needs.

One of the ways that BMW effectively supports the power of choice is through the CLAR platform architecture. Short for Cluster Architecture, BMW has designed the platform to support internal combustion engines (including mild hybrids), plug-in hybrids and all-battery electric powertrains, and intends to use it for all rear- and all-wheel drive.

Practically, this means that all new BMWs from 2 Series Coupé and above take advantage of the CLAR platform. Meanwhile, front-wheel drive BMWs are smaller, including 1 Series bloomand X1 and X2uses the UKL (Untere Klasse or ‘lower class’) platform and its derivatives.

The iX is an exception to this rule, with BMW claiming that it is built on a bespoke electric platform, yet remains highly compatible with the CLAR.

But even if BMW avoids setting an end date for the combustion engine, it is poised to use the next-generation “electric-first” architecture to succeed the CLAR.

Brief history

The first model in the BMW lineup to switch to the CLAR platform was the flagship G11 7 Series sedan, launched in 2015.

Formerly known as ’35up’ before being renamed CLAR, this generation of 7 Lines features a ‘carbon core’ bodywork made from a combination of carbon fiber, aluminum and steel, with the Bavarian brand claiming that this construction allows for a lightweight yet highly rigid structure.

In some ways, BMW’s CLAR shares some similarities with the CMF (Common Module Family) Architecture of the Renault-Nissan-Mitsubishi Alliance. Instead of a common chassis that can expand between certain hardpoints, BMW refers to clusters.

Each of these assemblies acts as a sub-module containing a set of components, so they can be more widely adapted to fit the vehicle being designed.

CLAR also allows the materials used to build a vehicle with greater versatility, with a combination of steel, aluminum and carbon fiber (as the 7 Series has suggested above) possible.

While the cheaper models in the BMW lineup don’t use the same carbon-core construction as the 7 Series, the nature of the CLAR has allowed BMW to roll it out relatively quickly across the majority of the vehicle lineup, with generations new of other models switched to it mid-2016 (G30 5 Series sedan) and 2021 (G42 2 Series Coupé).

Power of choice

Drivetrain versatility is a key benefit of BMW’s CLAR. To further streamline production, for combustion engines, BMW has developed a corresponding series of modular engines, where each cylinder/piston combination has a displacement of 500cc, across a range of engines. three, four and six cylinders in line.

This means that the majority of BMW vehicles sold with internal combustion engines today have a displacement of 1.5 liters (with the diesel variant being designated B37, while its petrol counterpart is referred to as B38). ), 2.0 liters (B47 / B48) and 3.0 liters (B57 / B58). In turn, BMW’s High Performance M Division created a special version of the B58 called the S58, for use in models such as the latest M3 and Competition M4.

One exception to this rule is BMW’s V8, with the brand continuing to produce the 4.4-liter S68 engine set apart from this modular family, for use in models such as the 760i xDrive new and X7 M60i.

With BMW’s fifth-generation eDrive powertrain, the brand also claims that key EV components can be used with the CLAR, such as the engine, power electronics, battery and related components. agencies, have also adopted a modular, scalable strategy and have been packaged in a way that allows them to be fitted across the entire CLAR line.

For example, the fifth-generation eDrive ‘drive unit’ integrates the engine, powertrain and electronics in a single compact housing and can be scaled to generate power from ​90kW to over 300kW (as per vehicle like new car BMW i4 M50).

The same scalable approach applies to modules and battery packs, to ultimately support vehicles with a range of up to 700km.

The main benefit of BMW’s ability to integrate multiple powertrains into the CLAR is the economies of scale and logistics that result from using the same production line.

For example, the 4-Series Gran Coupé and the electric i4 can be built side-by-side, while the iX3 is built in the same way. X3 models in China (note that for the Australian market, the iX3 is sourced from China, while the internal combustion engine X3 models are sourced from South Africa or the US).

Developing an electric vehicle from this base is significantly different from the more experimental, more distinctive approach that BMW took with the recently discontinued i3 model.

What’s next?

CLAR-based BMW models are likely to be produced at least after 2025. However, BMW has announced that it will debut its next-generation ‘Neue Klasse’ architecture same year.

Named after the Neue Klasse model introduced in the 1960s (such as the 1600 sedan) that revived BMW’s fortunes, BMW originally designed the Neue Klasse to work with an internal combustion engine, before changed course earlier this year and announced that the initial models launching on this architecture would be battery-electric only.

Regardless, the Bavarian marque claims that the Neue Klasse models will bring significant advancements in everything from EV powertrains to interior technology. BMW has confirmed that the first models to launch on the platform will be a BMW 3 Series sedan and an X3 sized SUV.

The latest rumors suggest that Neue Klasse will also see BMW switch from prismatic cells, to ‘4680’ cylindrical cells (46mm in diameter and 80mm in height) as being tested by Tesla.