Vitesco Technologies presents cost-effective dedicated hybrid transmission for PHEVs
10 December 2019
Vitesco Technologies, the Powertrain business area of Continental, presented at the CTI Symposium in Berlin (9-12 December 2019) a cost-effective and compact dedicated hybrid transmission solution with integrated electric machines, designed for use in applications such as plug-in hybrid electric vehicles (PHEVs).
At the heart of Vitesco Technologies’ solution is an expanded role for the electric motor, which no longer simply acts as a means of propulsion and energy recuperation.
So far it has not been possible to tap the full potential of plug-in hybrids and full hybrids for reducing CO2 emissions because the expensive powertrain of these vehicles puts them out of reach for many customers. We have identified further potential here which our DHT [Dedicated Hybrid Transmission] technology for cost-effective PHEVs is designed to leverage. With a view to cutting CO2 emissions, PHEVs are a form of electric mobility which deserves to become much more successful in the future.
—Stephan Rebhan, Head of Technology & Innovation at Vitesco Technologies
The basic aim of DHT technology for cost-effective PHEVs is to permit the design of very compact automatic transmissions with an integrated high-voltage electric motor on the output side of the transmission.
The Vitesco Technologies cost-effective PHEV prototype offers the driver the same standard of comfortable driving and shifting that until now has been associated with plug-in hybrids equipped with a conventional 6-speed automatic transmission. However, a DHT transmission with Vitesco technology has only four mechanical gears and has no mechanical synchromesh systems, auxiliary hydraulics or start clutch.
Moving off (in 1st and 2nd gear) and reversing are handled by the electric drive motor, while synchronization is performed by a starter-alternator that also provides fast and smooth starting of the internal combustion engine.
The reassignment of functions makes it possible to reduce the number of mechanical components in the transmission, which also saves space, weight and costs. This makes the DHT a natural choice for front transverse mounting in compact segment vehicles, where installation space is always a challenge.
Combined with a low-cost port-injection gasoline engine and all-electric-capable electric drive, for example, DHT technology clears the way for affordable, economical and comfortable vehicles capable of performing a wide range of daily trips in all-electric mode, with zero local emissions, Vitesco says. The DHT for cost-effective PHEVs is designed for speeds of up to 120 km/h in all-electric mode, and up to 160 km/h in hybrid mode.
This new PHEV solution draws on Vitesco Technologies’ wide-ranging systems expertise in terms of overall powertrain design, and comprehensive knowledge of electric drive technology.
By way of example, the smooth, quiet shifting offered by the DHT despite its simple dog-clutch design is entirely down to the high dynamic capability of the electric motor functions, which in turn requires a deep understanding of the relevant control technology.
DHT technology for low-cost PHEVs marks a further step in Vitesco Technologies’ systematic electrification strategy.
I knew hybridization could reduce requirements on the engine and make it simpler, but I hadn't spotted the potential on the transmission side. Looks like PHEV may be cheaper and thus quicker to come to the fore. I hope Vitesco wins big here.
Posted by: Engineer-Poet | 10 December 2019 at 06:46 AM
I do not think it is right to invest time and money in PHEV. The future will be at most extended range electric vehicles, or only battery electric vehicles.
Posted by: PSJ | 10 December 2019 at 07:44 AM
Vitesco Technologies (formerly the powertrain division of Continental AG) is a major supplier of e-axles to Groupe PSA (soon to include FCA) and Hyundai. So this may be used in many future PHEV.
The MAHLE Modular Hybrid Powertrain (MMHP), integrated, plug-in hybrid drive (GCC, 9/10/19) has a similar approach with emphasis on an efficient 2- or 3-cylinder, turbocharged gasoline engine using the MAHLE Jet Ignition (MJI) system. This MJI is used on the Ferrari F1 and Mahle is a key supplier to FCA.
One could imagine a Fiat Twin Air 900 cc engine with MJI and the Vitesco Hybrid transmission (with a good battery) would make an outstanding range extended or PHEV.
Posted by: Account Deleted | 10 December 2019 at 09:46 AM
The step forward that was missing to plug-in hybrid technology!
A P4 parallel hybrid configuration (motor after the gear reductions) allows a simpler, low cost transmission, with 3/4 gears, and downsized engine.
Have a look a this configuration developped by Green Propulsion in 2008
Posted by: Yves Toussaint | 11 December 2019 at 12:52 AM
I was thinking the same thing, gryf.
Posted by: Engineer-Poet | 11 December 2019 at 05:02 AM
Thanks E-P.
The Honda Clarity and Chevy Volt both excellent PHEV had less IC power than a top end Fiat Twinair (it has 105 hp). They are/were just too expensive. If battery tech can provide a lower cost solution than PHEV will be successful.
Posted by: Account Deleted | 11 December 2019 at 09:04 AM
It's not the battery tech per se. It's the brilliant combination of the e-motor handling ALL low-speed driving, the transmission requiring only 4 gear sets to still get 6 speeds, and the alternator-starter handling synchronization for shifting instead of mechanical gear synchronizers which add cost and bulk. It took transmission guys to find that last piece of the puzzle, and I salute them.
It should be no secret that I consider myself a fairly smart guy. I am quite happy to see advances that I was talking about 10-15 or more years ago finally show up in announcements here. To have something come out of left field like this surprises and delights me, because we need all of it and plenty more.
I think this puts the ball back in the engine guys' court. The Fiat Twinair is still a 4-cycle engine with a fairly complex valve train, and one version has a turbocharger. Given the relaxed driveability requirements of the hybrid drivetrain, might it be possible to go to a 2/4-cycle engine with pressure-operated intake valves (no intake cam) and either turbocharging for scavenging in 2-cycle mode or something like a Comprex pressure-wave system to harness exhaust pulse energy? Narrow operating RPM and such ceases to matter. Going to 2-cycle for high power slashes the engine size and weight. Getting rid of half the valve train cuts cost. Use electronics instead, the incremental cost of software is almost zero.
The transmission guys just got rid of a bunch of stuff, it's the engine guys' turn. "Simplicate and add lightness."
Posted by: Engineer-Poet | 11 December 2019 at 05:07 PM
One interesting problem is that this system would not work without any battery power so if you run the battery to zero, the car is probably just as dead as having a BEV with a dead battery and unlike the Volt the engine is not primarily driving the alternator. Maybe it is just a matter of having software to prevent the battery from being exhausted.
Posted by: sd | 12 December 2019 at 01:16 PM
The system has a fat alternator-starter on the engine side. Unless the battery fails or the car is left for a very long period, the likelihood of it going dead seems small.
Posted by: Engineer-Poet | 12 December 2019 at 08:39 PM
E-P
Your point of looking at 2 stroke engines without complex valve trains describes where the U.S. Army is headed for the next generation combat infantry vehicle using the Achates opposed piston engine and a more electric transmission as well, check here.
This could filter down to possibly a 3 cylinder PHEV pickup.
Posted by: Account Deleted | 12 December 2019 at 09:15 PM
Twenty years ago, I said that auto manufacturers were using complexity as a problem solving tool to decreasing marginal improvement, and that parsimony should be tried. This is an effort in that direction. It could be that PSA/FCA could be the first to tap into this, and the vehicle I would chose as a test case is the Qubo/Fiorino/Bipper/Berlingo quads. With their small on the outside/big on the inside, versatile interior, sliding side doors and huge tailgate design morphology, they have a greater potential than has been used to date. A PHEV high roof city delivery vehicle, 5 seat MPV, or stretched 7 seat MPV has high functionality at lower weight. At least in the Americas, people prefer a high seating position and more versatility than a sedan can offer. FCA and PSA have off the shelf components, like the Twinair or 1 liter threes as a front end power unit. FCA has the best stow and go seats in the industry. The QFBB quads have not sold in such huge numbers that if they fail in the market, they won't hurt the other brands.
Posted by: Fred Schumacher | 14 December 2019 at 07:42 AM