Toyota HSD vs P2

The article is generalizing the upcoming parallel hybrids as P2 but it is not accurate.

Hyundai and Kia hybrid use one clutch (should be named P1). Nissan/Infiniti hybrid has two clutches (P2).

Volt is a series-parallel hybrid with 3 clutches (should be SP3). Prius including PHV is a series-parallel hybrid with zero clutch (SP0).

Clutch sounds good for direct mechanical power transfer but it also means the gas engine RPM is locked in with the wheels. You can toss out the most efficient BSFC region away with clutches and step gears. The big advantage of HSD is the ability of series hybrid to stay in the sweetest BSFC region for the highest fuel efficiency.

 

^^ Good point.

I've been looking for a diagram or schematic of the Sonata Hybrid powertrain. Does one exist?

 

But the Hyundai setup does not have the MG RPM limit the HSD has.

If you want to drive an affordable car with a dual clutch automatic check out the Ford Fiesta. The damn thing shifts faster than I ever could in a manual and you never has a loss of torque even during shifts.

I know the clutch system in the Hyundai works between the motor and engine but it should be similar in speed and fluidity.

If anything we should all be happy because this means they will all get better if this technology is efficient and powerful.

 

Hyundai hybrid has 1 clutch with two motors. Infiniti hybrid has 2 clutches with one motor.

New simplified hybrid drive systems from Hyundai, VW, and FEV reduce cost - Vehicle Electrification - SAE

 

Weird, the article about the Hyundai that I read said it had a dual clutch...

 

Wait a minute, did I read this correctly? This article says that the Hyundai has an additional 8 kW belt-driven motor/generator/starter connected to the engine that operates in series with the 30 kW electric motor/generator in EV mode.

It's like a supersized alternator that also acts as a starter when the clutch is disengaged.

So the Hyundai has two motors, a 2.4 L engine, 6-speed transmission, wet multidisc clutch, and li-ion battery.

The extra motor is why it doesn't need a 2nd clutch.

 

Yes, you got it right. ISG (Integrated Starter/Generator) is much smaller than Prius MG1. It doesn't need to provide that much power to the traction motor since that also is rated with less power.

Both motors in Hyundai Blue Drive (HBD) can be downsized because it goes through an automatic transmission to provide suitable torque. HSD doesn't have these extra step gears, only a fixed reduction gear ratio.

We'll have to find out the EV performance of HBD (lower power traction motor with an automatic transmission). My guess is, it will be as good as HSD because the HV battery can provide 34 kW comparable to 30kW (Camry hybrid) and 34 kW (Fusion hybrid). Shifting gears in EV mode will be interesting.

The advantage of HBD is getting away with smaller MGs and PCU (power control until) but the disadvantage is the need for a mechanical (step gear or CVT) transmission.