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Suzuki Vitara full hybrid

As its brand enters its 101st year, Suzuki has developed its first cost-effective high-voltage hybrid, with a technical specification dictated firmly by market forces, as Rob Marshall discovers.

It is very easy to misunderstand Suzuki’s car division. While it may be a relatively small player in the UK, the company has a vast presence in other markets. Notably, Maruti Suzuki has close to a 50% market share in India. Yet, in the British Isles, Suzuki is neither a budget brand, nor one chasing fleet sales, but it focusses on value and dependability. Operating mainly through family-owned dealerships, most of its sales are to private individuals, who cannot benefit from significant tax incentives to offset the high-purchase price of an EV. Interestingly, Suzuki GB PLC states that its customers are two part-exchanges away from going fully electric.

Why the rush?

These reasons may explain why the brand has been comparatively conservative and relatively slow to embrace electrification, compared with other carmakers. Instead, the company has preferred a simpler approach, focussing on efficiency savings as a means of slashing CO2 emissions, including cutting weight, instead of adding technical complexity. Colin Chapman would be proud. Admittedly, the mild-hybrid Smart Hybrid Vehicle by Suzuki (SHVS) made some difference but its effectiveness was limited by being a 12-volts system, which was necessary to keep asking prices down.

It took until 2020 for the system to be uprated to 48-volts architecture.

The GDI 1.5-litre engine is used instead of the old 1.0-litre turbocharged Boosterjet unit. This makes sense, as turbochargers do not benefit from sudden engine shutdowns, due to lubrication starvation and localised overheating. Considering Suzuki’s experience with developing its own motorcycle, marine and motorcar petrol engines, this cam chain unit is likely to be reliable.
Suzuki’s Full Hybrid is a parallel hybrid system, in which an electric motor is positioned between the ICE and the transmission. Both systems drive the road wheels. Highlighted are the battery pack and the drive motor but note that the Full Hybrid also employs a belt-driven ISG.

Yet, to keep development costs low, Suzuki has leaned on Toyota for its high-voltage expertise as a stop-gap. The Suzuki Across is a badge-engineered Toyota RAV4 Plug-In Hybrid, whereas the British-built Swace is a Corolla Touring Sports. This decision has bought Suzuki sufficient time to develop its first high-voltage architecture, which appears beneath the bonnet of the familiar, capable, attractive but ageing Hungarian-built Vitara, a model that was introduced in 2015.

Efficiency up but costs down

The New Vitara Full Hybrid sells alongside the Vitara Mild Hybrid but utilises a 140-volts drivetrain. Compared to other high-voltage hybrids, this is comparatively low but is still high enough to dictate that technicians are EV qualified. Another curiosity is the AGS (Auto Gear Shift) gearbox, which is neither an epicyclical transmission, nor a DCT/twin-clutch unit. It is a manual gearbox, with selectors and clutch operated by robotics, dictated to suppress manufacturing costs. Using high-voltages and more sophisticated transmissions means more expensive and heavier parts, risking Full Hybrid Suzukis becoming too expensive in western markets, let alone in the growing east.

As expected with Suzuki, while its hands are tied with its driveline hardware, its engineers have succeeded in minimising the downsides. Driveline shunts have been virtually eliminated, having the high-voltage drive motor/generator powering the AGS gearbox’s output shaft via a chain drive, which Suzuki
says fills the torque gap during gear shifts and provides a smoother transition of power. A reduction gear also reduces motor speeds, enhancing torque. The system also incorporates a ‘coast’ mode, where the engine stops running completely on the overrun. A dual mass flywheel also absorbs the associated driveline forces, as the engine shuts down and restarts.

The main drive motor/generator and its chain drive are integral within the compact ASG manual transmission. The car also boasts three batteries. An Enhanced Flooded lead-acid Battery (EFB) for the 12-volt electrics beneath the bonnet, a 12-volt lithium-ion battery for the ISG is beneath the passenger seat and the high voltage battery pack and inverter are situated towards the rear.
Again, to keep the vehicle price down, the Vitara Full Hybrid employs an EFB starter battery, rather than a more expensive AGM.

As with Suzuki’s mild-hybrid SHVS, a belt-driven Integrated Starter Generator (ISG) also features. Not only does this provide the smart alternator function but it also restarts the engine. However, a conventional pre-engaged starter motor is also employed for the initial cold start. Yet, the ISG does not provide any engine torque assist, because this task is performed by the high-voltage motor/generator.

The manual gearbox has its gears and clutch controlled electro-hydraulically. These single-clutch automated manuals are becoming less popular in western markets. Suzuki has succeeded in reducing most of the associated disadvantages with well-engineered software but it remains neither as quick (nor as complex and expensive) as a DCT, such as Volkswagen Group’s DSG. Pictured is the electro-hydraulic control unit, mounted on top of the transmission.

In summary

Suzuki’s first full hybrid may be misunderstood but its execution is sound. The company may not pack its cars with the latest technology but, in a world where other manufacturers are scrambling to outdo each other in the EV stakes, sometimes, being more circumspect is the wiser approach.

As with most of the latest models, it takes time for the aftermarket to establish the engine oil specifications. The latest formulations boast extra timing chain protection.

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