The plug-in hybrid all-wheel drive for the VW Multivan and California

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Volkswagen is currently sending out a press release on the extended drive range for its minibus models, which are already on sale. Following the PHEV for the Transporter and Caravelle with front-wheel drive and 10.4 kWh called eHybrid, the commercial vehicle department is now offering an all-wheel hybrid drive with on-demand electrically driven rear axle for the Multivan and California. As usual for Volkswagen, the all-wheel drive is called "4motion", which means it now has the additional designation "eHybrid 4motion". With a 19.7 kWh battery, a model-dependent range of 85 to 95 kilometers in the WLTP is possible, Volkswagen writes. As usual, the electric consumption is higher than that of an electric car; VW gives the weighted, combined energy consumption as 22.3 kWh/100 km plus 0.8 l/100 km. The admittedly not quite comparable VW ID.Buzz achieved an average real-world consumption value of 22.1 kWh/100 km in our test.

The ominous "100 percent"

VW combines its advanced hybrid drive with an electric motor in the dual-clutch gearbox and an independent electric drive at the rear. How the power is distributed is decided by an electronic brain that knows the slip values of all four wheels almost in real time. Above 130 km/h, the rear electric motor is switched off. Up to 100 percent of the drive force can be applied to either the front or rear axle, although the values differ: The rear electric motor delivers 100 kW and 250 Nm, the front 85 kW and 330 Nm, and even more if required in combination with the 130 kW 1.5-liter combustion engine with a maximum of 250 Nm. However, "100 percent of the drive power" means neither "85 plus 130 kW at the front and 100 kW at the rear" nor the maximum 180 kW system output on each axle, but only the maximum possible power that can be available on one axle at that moment.

How much this is varies and is not specified by VW. The fact that this can never be the total force that the entire system can apply is ignored in this blanket statement. It can be even less as soon as the battery is discharged: according to Volkswagen, the drive is designed in such a way that the electric rear axle drive can also become active when the battery is "empty". The power required for the drive should then come from the front electric motor with combustion engine drive. It goes without saying that the performance cannot be as high as with a charged battery. Rather, it is significantly limited because the front electric motor, which then serves as a generator, can produce a maximum of 85 kW – minus the multiple conversion losses.

However, this is pretty irrelevant when used as a starting aid on mud or snow. After all, it's all about moving forward and not about breathtaking driving dynamics. And that is precisely why this all-wheel drive deserves praise. Because not every manufacturer designs the electrical components in such a way that all wheels can always be driven.

"Hang-on all-wheel drive" and sailing

To further increase efficiency, the control system not only switches off the power for the rear axle drive when not required, it can also disconnect the electric motor from the drive shafts using a claw clutch. Whenever possible, the combustion engine is also automatically disengaged to allow the car, which weighs over 2.5  tons empty, to "sail" with as little parasitic drag loss as possible.

The person at the wheel can influence the characteristics of this control system within limits. If they move the selector lever from "D" to "S" sport mode, the all-wheel drive is constantly available for tackling slippery roads or the notorious wet meadow, which has long been proverbial for good reason. This configuration with correspondingly powerful electric motors offers full hybrid efficiency and traction on both axles at all times if required, as VW writes.

Like a diesel, but usually better

Only the electric rear axle drive is completely new; it has been integrated into the existing independent suspension on semi-trailing arms. Volkswagen developed the remaining hybrid drive with a system output of 180 kW and a combined total output of up to 350 Nm from the PHEV with front-wheel drive and 160 kW total output presented in the Multivan in 2021. Its 1.4-liter combustion engine with 110 kW already had an 85 kW electric motor on the 6-speed dual-clutch transmission and a 10.4 kWh battery. The petrol engine now has a displacement of 1.5 liters, but continues to work with a turbocharger with variable geometry (VTG) and in the Miller cycle, i.e. early closing of the intake valves. In combination with the large battery and a high recuperation capacity, the drive with a discharged battery comes close to the consumption of comparably powerful diesels at 7.5-7.9 l/100 km. With a diesel engine, the car has a towing capacity of two tons; as a hybrid, it can only tow 1600 kilograms. However, the hybrid drive offers superior turning pleasure with similar torque advantages thanks to additional electric thrust.

The lithium-nickel-cobalt-manganese battery was given a liquid cooling system to enable the high recuperation performance. With the charging capacities now possible, VW has increased the practicality: instead of the 3.6 kW in the previous Multivan eHybrid, which was never really up to date, the battery can now be charged with up to 11 kW alternating current in three phases.

For the first time, the minibus can also accept up to 50 kW direct current at DC fast-charging stations. This is a real advantage because it supports occasional charging, for example when shopping. Volkswagen states that the value according to DIN70080 for the "customer-relevant charging process" is then 40 kW. Under the best conditions at 50 kW, it should take 26 minutes to charge the battery from ten to 80 percent. Another advantage of the powerful battery is the standard electric parking cooler. Its electrically powered air-to-air heat pump can cool, ventilate or heat the cars when charging, parking or camping.

The two models are configured to be particularly expensive even in their basic configuration. However, the plug-in hybrid pushes the price up even further: For a Multivan eHybrid 4motion you are looking at 70,947 euros, for 83,229 you can order a California eHybrid 4motion.

(fpi)