Software will be king in making our electrified future fun to drive, and Honda’s first go at keeping the driver involved is a fascinating one. Like any deeply committed petrolhead, I struggle mightily with the idea of simulating a vital portion of the driving experience. Nearly every time I’ve given those simulations a chance, though, I surprisingly ended up liking the result. I say nearly, because there are exceptions. Cough, Fratzonic exhaust, cough.
Honda’s S+ Shift system is a perfect example of the kind of conundrum I’m talking about. The two-motor hybrid powertrain in the Prelude doesn’t actually have a transmission in the traditional sense. An electric motor drives the front wheels in most cases, while an electronically controlled clutch allows for direct drive from the engine during steady-state, high-speed cruising. Naturally, that results in a rather boring powertrain, one Honda certainly didn’t deem acceptable in the Prelude, hence the development of this new, simulated eight-speed dual-clutch transmission. It’s weird.
View Price on AmazonThe Prelude was even featured in our Weird issue, in large part due to this feature. Strangeness aside, I was also hopeful. Honda has a long history of shipping a driving experience far greater than the sum of its parts might appear at first glance. The various generations of Prelude have always played a vital role in this history, so I went to Yoshiharu Saito, Prelude powertrain project leader, to learn how it works.
Honda emphasizes two previous steps forward in hybrid drive technology it made before S+ Shift that led to this next technology being possible: Linear Shift Control and Direct Acceleration. The first, Linear Shift Control, was developed to bring what the driver hears from the engine in line with their inputs. Naturally, Honda’s two-motor hybrid system uses the internal combustion engine as a generator, which means it’s simply buzzing away to its own tune in an effort to fill the battery pack in the most efficient way possible. The electric traction motor uses power from the battery to accelerate the car. Drivers found the disconnect between engine noise and forward motion odd, though, so Honda engineered Linear Shift Control to align the engine noise such that it sounds like it’s revving and “shifting” through gears when your foot is on the throttle, like a traditional transmission.
Meanwhile, Direct Acceleration is simply a means to fire the engine up early (ensuring plenty of power is being fed to the battery) to supply much more effective and natural torque off the line should a driver ask for a quick start. As you might suspect, virtually all of the magic needed to produce S+ Shift is in the software. Never press the S+ Shift button on the center console, and the Prelude will drive like Honda’s other hybrid vehicles. Enter the S+ Shift world, though, and you step into Honda’s Narnia of simulated shifting.
“Honda S+ Shift was developed not only to create the enjoyment of behaving like a DCT, but also as a technology that enhances the fundamental powertrain values of responsiveness and linearity,” Saito says. “The response and linearity to even slight accelerator input changes during acceleration and deceleration, such as on uphill roads or freeways, are capabilities not previously achieved in conventional hybrids, and we believe this allows drivers to enjoy a true dialogue with the vehicle.”
The secret sauce of what makes the new Prelude’s powertrain engaging is all in the fine-tuning and calibration of the electric motor and internal combustion engine. While Honda tells me it’s not trying to simulate the sound of any specific engine from its history, it does admit the torque curve and acceleration are meant to mimic a 2.4-liter naturally aspirated four-cylinder. That seems perfectly reasonable considering the electric motor doing the real accelerating is a mildly torquey little beast.
Source: roadandtrack.com
