Tech: How Kawasaki’s planned new hybrid engine will work
Mixing petrol and electric power on two wheels
‘A boost button gives access to instant torque’
Kawasaki’s confirmation that they’re working on a hybrid might seem like an admission that they’re following car companies. But a deeper dive into the plans shows they want to create a very different sort of hybrid.
The tech that’s widely used on four wheels, where electric motors and petrol/diesel engines share the workload, tends to focus on a seamless transition between the power sources. Automatic or CVT gearboxes are the norm and changing the behaviour of the systems involves working through layers of menus.
But Kawasaki know riders want more control over the way their machines behave and over recent months they’ve filed dozens of patents relating to how they want to combine that controllability with hybrid tech. Most significantly, the firm’s hybrid bike is set to use manual transmission, just like a normal petrol bike, but with two sources of power: the petrol engine, connected via a conventional clutch, and a permanently engaged electric motor. Although hybrids have been dismissed by bike firms because of the packaging problem of fitting a conventional engine and fuel system and an electric drive and battery into a normalsized motorcycle, Kawasaki’s engineers are convinced there’s potential. Not just because it’s environmentally friendly but because it means you can have the instant, zero-revs torque of an electric motor and the higher-rev power of petrol. You also eliminate range anxiety, as refuelling is done conventionally, and get rid of the need to lug around a big, heavy battery since you’ll only do a few miles at a time on electricity alone. By using a manual gearbox and conventional clutch, the firm can keep the riding experience familiar, but the throttle position doesn’t just govern the engine. Instead it’s an indicator of how much torque you’re demanding, and the electronics decide how best to provide it. From standstill, the initial thrust is largely electric, filling in the low-rev lack of torque of the petrol engine. Once on the move, the bike uses electric power to fill in any gaps in the engine’s power and torque curves to make for the sort of responsiveness you’d expect from a larger machine. Kawasaki are also developing ways to give riders constant control over the mix. They have developed a new twist-grip that adds a four-way toggle for your right thumb. The switch is mounted on the twist-grip itself, so you keep your thumb on it regardless of throttle position – allowing you to switch between modes that rely more on electric or petrol power. Below it sits a ‘boost’ button which instantly gives access to the maximum available torque from both power sources.