{{Infobox automobile platform | name = GM Voltec platform | image = | aka = E-Flex | manufacturer = General Motors
| predecessor = | successor = | production = 2010–2019 | class = Extended-Range EV (EREV) | similar = | body_style = | engine = | transmission = | front_suspension = | rear_suspension = | wheelbase = | related = | vehicles = Chevrolet Volt, Cadillac ELR, Holden Volt, Opel Ampera, Vauxhall Ampera }} '''Voltec''', formerly known as '''E-Flex''', is a General Motors powertrain released in November 2010. The Voltec architecture is primarily a plug-in capable, battery-dominant electric vehicle with additional fossil fuel powered series and parallel hybrid capabilities.<ref Name=R1>{{cite web|title=The Voltec System - Energy Storage and Electric Propulsion|url=https://www.researchgate.net/publication/262004450|last1=Matthe|first1=Roland|last2=Eberle|first2=Ulrich|date=2014-01-01|accessdate=2014-05-04}}</ref><ref name=RG>{{cite web |title=Wasserstoff und Elektromobilität - Für ein intelligent verknüpftes Energie- und Verkehrssystem|url=https://www.researchgate.net/publication/236344244 |last1=Eberle|first1=Ulrich|date=2012-08-05| accessdate=2013-05-05}}</ref>
Voltec vehicles like the Chevrolet Volt are all electrically driven, feature common drivetrain components, and will be able to create electricity on board using either a fuel cell or a gasoline motor to generate electricity. Regenerative braking contributes to the on-board electricity generation.
Voltec is a portmanteau word from ''Volt'', ''Vo''r''tec'' and technology.
==Drivetrain== ===Generation 1=== ====E-Flex concept (2007)==== thumb|left|E-Flex Propulsion System (Chevrolet Volt concept) The Voltec drivetrain was initially demonstrated as the '''E-Flex Propulsion System''' in the 2007 Chevrolet Volt concept vehicle that debuted at that year's North American International Auto Show.<ref name=R1 /><ref name="carconnection">{{cite web|url=http://www.thecarconnection.com/Auto_News/Green_Car_News/GM_Plugs_Fuel_Cells_into_Volt.S196.A12244.html|title=GM Plugs Fuel Cells into Volt|first=Paul A.|last=Eisenstein|date=2007-04-19|publisher=The Car Connection}}</ref><ref name=RSC>{{cite web |title=Sustainable transportation based on electric vehicle concepts: a brief overview |url=https://www.researchgate.net/publication/224880220 |last1=Eberle|first1=Ulrich|first2=Rittmar|last2=von Helmolt |publisher=Royal Society of Chemistry |date=2010-05-14| accessdate=2010-06-08}}</ref> GM touted E-Flex as an attempt to standardize many components of possible future electrically propelled vehicles, and to allow multiple interchangeable electricity-generating systems.<ref>{{cite web|url=http://www.autobloggreen.com/2007/01/07/detroit-auto-show-general-motors-e-flex-platform/ |title=A look at the GM E-Flex platform |first=Sam |last=Abuelsamid |work=AutoBlogGreen.com |date=2007-01-07 |accessdate=2007-01-13}}</ref> GM described the Volt an E-REV, for "extended-range electric vehicle", rather than a hybrid.<ref Name=R1 /><ref name="RSC"/><ref>{{cite web|url=http://www.gm-volt.com/2007/11/23/gm-calls-the-volt-an-e-rev/ |title=GM Calls the Volt an E-REV |first=Lyle J. |last=Dennis, M.D. |work=GM-Volt.com |date=23 November 2007 | accessdate=2007-11-23}}</ref> In general, power is drawn from the batteries for the electric traction motor which moves the vehicle.
As realized in the 2007 Volt concept, the initial E-Flex design includes an electric traction motor with peak power and torque outputs of {{cvt|120|kW}} and {{cvt|320|Nm}}, a 1 L 3-cylinder gasoline engine coupled to a generator with an output of {{cvt|53|kW}}, and a {{convert|16|kWh|MJ|abbr=on|lk=on}} lithium-ion battery energy storage system.<ref name="RSC"/><ref name=GCC-2007>{{cite news |url=https://www.greencarcongress.com/2007/01/gm_introduces_e.html |title=GM Introduces E-Flex Electric Vehicle System; Chevrolet Volt the First Application |date=6 January 2007 |work=Green Car Congress |access-date=4 September 2024}}</ref><ref>{{cite web |url=http://www.chevrolet.com/pop/electriccar/ | title=What if you could commute to work all week without using a drop of gasoline? |archive-url=https://web.archive.org/web/20070609095141/http://www.chevrolet.com/electriccar/ |archive-date=June 9, 2007 |url-status=dead}}</ref> The concept has a fuel tank with {{cvt|12|USgal}} capacity, yielding a claimed combined electric and gasoline driving range of {{cvt|640|mi}} and an overall fuel economy of {{cvt|50|mpgUS}}. Using a conventional household outlet (110 V AC, 15 A), the battery could be recharged in 6{{frac|2}} hours.<ref name=GCC-2007/>
The E-Flex could be considered a power-split hybrid, as the platform shares aspects of both series hybrid and parallel hybrid designs. Like a series hybrid, the internal combustion engine is not connected to the transmission, so it can run at a constant speed for both optimal efficiency and mechanical simplicity (i.e., there is no need for variable cam phasing). Starting from rest, E-Flex uses the electric traction motor alone to drive the wheels; mechanical power from the engine is used strictly to drive the generator, which in turn charges the battery pack. At high demand in charge sustaining mode, the motor output stays high to build up a charge.<ref Name=R1 /><ref name="RG"/><ref name=GCC-2007/>
However, by definition, the E-Flex transmission design makes it a parallel hybrid, as the planetary gearset which drives the wheels is coupled to both mechanical power (from the engine) and electrical power (from the motor), similar to the operation of a Toyota Prius. The Prius uses the electric motor to assist the engine; in contrast, the Voltec design uses the engine to assist the electric traction motor. As a result, the Voltec design engages mechanical assist from the engine only when the battery is depleted to 30% state of charge or lower.<ref Name=R1 /><ref name="RG"/><ref>{{cite news |url=http://www.motortrend.com/features/editorial/1010_unbolting_the_chevy_volt_to_see_how_it_ticks/index.html |title=Unbolting the Chevy Volt to See How it Ticks |date=October 13, 2010 |work=Motor Trend |access-date=4 September 2024}}</ref><ref name=GCC-2007/>
[[File:Chevy Volt DCA 01 2010 8811.JPG|thumb|right|upright=1.5|In this production Voltec (gen 1) powertrain, the internal combustion engine / range extender is on the left and the Voltec drive unit is on the right. The coiled bundle of orange high-voltage cables between the engine and drive unit connect the traction power inverter module (TPIM, on top) to the transaxle below (not visible).]] Since the electric traction motor draws power from the battery, the platform supports multiple options for charging the battery. As described at the 2007 NAIAS, the initial configuration used a turbocharged 1.0-liter engine with three cylinders; this was a flex-fuel engine capable of running gasoline or E85 (85% ethanol, 15% gasoline), although this engine never made it to production vehicles.<ref name=GCC-2007/> Alternative engine-generator options mentioned included a pure ethanol (E100) engine, a diesel engine capable of running biodiesel fuel, or even a hydrogen fuel cell, once that technology becomes practical. Another power-source option which does not rely on an internal combustion engine at all, was demonstrated in the Volt hydrogen fuel cell concept vehicle, which appeared at the 2007 Shanghai Auto Show.<ref name="carconnection"/> However, due to the high cost of fuel cells compared to newer lower cost lithium batteries, General Motors has publicly suggested that the Volt will not be using fuel cells in any near term production vehicles.<ref>{{cite web|url=https://www.wsj.com/articles/SB120468405514712501 |first=Edward |last=Taylor |title=GM, Toyota Doubtful on Fuel Cells' Mass Use |date=2008-03-05 |accessdate=2008-04-08 |publisher=Wall Street Journal}}</ref>
====Production==== The first generation production Volt is propelled by an electric motor with a peak output of {{convert|111|kW|hp|abbr=on}}. Ordinarily, the Volt charged while at home overnight (plug-in hybrid-mode) through a charging port.<ref>{{cite news|url=http://www.cnn.com/2007/AUTOS/01/07/detroit_chevrolet_volt_concept/index.html |title=GM shows Chevy plug-in concept |publisher=CNNMoney.com |date=2007-01-08 |accessdate=2007-01-12}}</ref> A full charge reportedly takes 10-12 hours from a standard North American 120 V, 15 A household outlet, or 4 hours from a 240 V 15 A SAE J1772 electrical vehicle supply.{{citation needed|date=August 2012}}
The lithium-ion battery in the initial Voltec production vehicle is kept in a state-of-charge (SOC) range of between 30% and 80%, with the on-board generator that works to maintain the battery at the 30% charge level.<ref name="RSC"/><ref>{{cite web|url=http://www.gm-volt.com/2007/08/29/latest-chevy-volt-battery-pack-and-generator-details-and-clarifications/ |title=Latest Chevy Volt Battery Pack and Generator Details and Clarifications |first=Lyle J. |last=Dennis, M.D. |work=GM-Volt.com |date=29 August 2007 | accessdate=2007-08-29}}</ref> As initially released, the high-voltage storage battery had a gross capacity of 16 kW-hr; it was upgraded to 16.5 and then 17.1 kW-hr in 2014.<ref>{{cite news |url=https://www.motortrend.com/reviews/2016-chevrolet-volt-first-test-review/ |title=2016 Chevrolet Volt First Test Review |first1=Kim |last1=Reynolds |first2=Julia |last2=LaPalme |date=September 1, 2015 |work=Motor Trend |access-date=4 September 2024}}</ref>
The GM codes for the first-generation Voltec powertrain drive unit (transaxle) are 4ET50 (RPO MKA for the Chevrolet Volt) and 4ET55 (RPO MKD for the Cadillac ELR). This transaxle integrates a torque dampener (serving the same purpose as a torque converter in a conventional automatic transmission), motor/generator A, the planetary gearset, three clutches, drive motor B, and a final drive including a reduction gear and differential.<ref>{{cite web |url=https://gearsmagazine.com/magazine/tackling-a-4et50-hybrid/ |title=Tackling a 4ET50 Hybrid |date=June 2017 |first=Steve |last=Garret |work=Gears |access-date=4 September 2024}}</ref> <!-- Deleted image removed: thumb|The Ampera is one of the cars which will have the GM Voltec platform and will be sold in 2011{{deletable image-caption|Wednesday, 3 June 2009}} -->
{|class="wikitable" style="font-size:90%;text-align:center;" |+Voltec (Generation 1) variations ! rowspan=2 {{diagonal split header |Vehicle |Specification}} ! rowspan=2 | Gasoline engine ! colspan=3 | Electric ! rowspan=2 | Combined output ! colspan=3 | Consumption / Economy<ref>{{Fuel Economy Guide |year=2014 |page=38}}</ref> |- ! M/G A !! M/G B !! Battery ! EV !! Hybrid (City/Hwy) !! Electric range |- ! Chevrolet Volt<ref>{{cite news |url=https://www.caranddriver.com/reviews/a15128758/2011-chevrolet-volt-test-review/ |title=2011 Chevrolet Volt Full Test |first=Dave |last=Vanderwerp |date=October 10, 2010 |work=Car and Driver |access-date=4 September 2024}}</ref> | 1.4 L ''LUU'' I4<br/>{{cvt|84|hp}}<br/>{{cvt|93|lbft}} | {{cvt|74|hp}}<br/>{{cvt|186|Nm|order=flip}}<ref name=GCC-20150423/> || {{cvt|149|hp}}<br/>{{cvt|273|lbft}} | 9 kW-hr<br/>16 kW-hr (gross) | {{cvt|149|hp}}<br/>{{cvt|273|lbft}} | {{cvt|98|mpge|kWh/100km}} || {{cvt|35|/|40|mpgus|l/100km}} | {{cvt|38|mi}} |- ! Cadillac ELR<ref>{{cite news |url=https://www.caranddriver.com/reviews/a15112864/2014-cadillac-elr-coupe-plug-in-hybrid-tested-review/ |title=Tested: 2014 Cadillac ELR Coupe Plug-In Hybrid |first=K.C. |last=Colwell |date=January 22, 2014 |work=Car and Driver |access-date=4 September 2024}}</ref> | 1.4 L ''L2Z'' I4<br/>{{cvt|86|hp}}<br/>{{cvt|94|lbft}} | {{cvt|74|hp}}<br/>{{cvt|186|Nm|order=flip}} || {{cvt|157|hp}}, EV mode<br/>{{cvt|181|hp}}, hybrid<br/>{{cvt|295|lbft}} | 16.5 kW-hr | {{cvt|217|hp}}<br/>{{cvt|295|lbft}} | {{cvt|82|mpge|kWh/100km}} || {{cvt|31|/|35|mpgus|l/100km}} | {{cvt|37|mi}} |}
====Operation==== As described in the patent, the engine is coupled to the transaxle using a torque dampener, which is a selectively engaged clutch that couples the engine with the rotor of Motor/Generator A. In addition to the selective coupling with the engine, Motor/Generator A also may be coupled to the ring gear of a planetary gearset using a second clutch. A third clutch is provided to selectively ground the ring gear. Motor B is permanently coupled to the sun gear of the same gearset; the pinion carrier drives the wheels through a reduction gear and differential. Using this design, the transaxle is able to switch between series hybrid and split output modes, with low ranges provided as a series hybrid using one motor and high ranges provided by split output which blends output from both motors.<ref name=US7867124B2/><ref>{{cite journal |doi=10.4271/2011-01-0887 |title=The GM 'Voltec' 4ET50 Multi-Mode Electric Transaxle |first1=Michael A. |last1=Miller |first2=Alan G. |last2=Holmes |first3=Brendan M. |last3=Conlon |first4=Peter J. |last4=Savagian |issn=1946-3936 |journal=SAE International Journal of Engines |date=2011 |volume=4 |issue=1 |pages=1102–1114}}</ref>
There are six basic operating modes, depending on clutch engagement and engine operation;<ref name=US7867124B2>{{cite patent |country=US |number=7867124B2 |status=Patent |title=Output split electrically-variable transmission with electric propulsion using one or two motors |invent1=Brendan M. Conlon |invent2=Peter J. Savagian |invent3=Alan G. Holmes |invent4=Michael O. Harpster, Jr. |assign=GM Global Technology Operations LLC |fdate=September 10, 2007 |pubdate=January 11, 2011}}</ref> General Motors have classified the modes according to power flow to or from the battery. These include two charge-depletion (all-electric) modes, CD1 and CD2, and two charge-sustaining (extended-range / hybrid) modes, CS1 and CS2. In brief:<ref>{{cite book |url=https://www.sae.org/images/books/toc_pdfs/BELS070.pdf |title=Lithium-Ion Batteries: Advances and Applications |first1=Roland |last1=Matthé |first2=Ulrich |last2=Eberle |editor-first=Gianfranco |editor-last=Pistoia |chapter-url=https://www.selidori.com/tech/00000-04999/1090-6SijD.pdf |chapter=8: The Voltec System — Energy Storage and Electric Propulsion |pages=151–176 |date=December 16, 2013 |publisher=Elsevier Science |isbn=9780444595164}}</ref>{{rp|164–165}} * CD1: Motor B is used for tractive power * CD2: Motor B is used for tractive power, assisted by Motor/Generator A as a motor * CS1: Motor B is used for tractive power, and the engine is used to generate electricity using M/G A as a generator (series hybrid) * CS2: Motor B is used for tractive power, assisted by the engine (output power-split)
The patent includes two additional neutral modes where little to no tractive power is being applied.<ref name=US7867124B2/>
{|class="wikitable" style="font-size:100%;text-align:left;" |+Voltec (Generation 1) operating modes, from U.S. Patent 7,867,124 B2<ref name=US7867124B2/> ! rowspan=2 | Mode !! rowspan=2 | Name !! rowspan=2 | Diagram ! colspan=3 | Clutches !! rowspan=2 | (E)ngine !! colspan=2 | M/G ! rowspan=2 | Description |- ! C1 !! C2 !! C3 ! A !! B |- ! style="font-size:150%;" | CD1 (1) | One motor, electric-only | frameless|upright=1 | {{yes C}} || {{no X}} || {{no X}} | {{no X}} | style="background:#fff;" | off || style="background:#bbf;" | M | Engaging clutch 1 (C1) grounds the ring gear (R). Motor B is used as the traction motor, driving the sun gear (S); since the ring gear is grounded, the pinion gears (P) are forced to turn, driving the wheels through a reducing gear and differential. |- ! style="font-size:150%;" | CD2 (6) | Two motor, electric-only | frameless|upright=1 | {{no X}} || {{yes C}} || {{no X}} | {{no X}} | style="background:#bbf;" | M || style="background:#bbf;" | M | Engaging clutch 2 (C2) couples Motor/Generator A to the ring gear (R), assisting Motor B, which is used as the primary traction motor, driving the sun gear (S); the wheels are driven by the pinion gears (P) through a reducing gear and differential. |- ! style="font-size:150%;" | CS1 (2) | Series hybrid | frameless|upright=1 | {{yes C}} || {{no X}} || {{yes C}} | {{yes C}} | style="background:#fdb;" | G || style="background:#bbf;" | M | Engaging clutch 1 (C1) grounds the ring gear (R), and clutch 3 (C3) couples the engine (E) to Motor/Generator A, which operates as a (G)enerator to charge the storage battery. Motor B is used as the sole traction motor, driving the sun gear (S); since the ring gear is grounded, the pinion gears (P) are forced to turn, driving the wheels through a reducing gear and differential. |- ! style="font-size:150%;" | CS2 (3) | Output power-split | frameless|upright=1 | {{no X}} || {{yes C}} || {{yes C}} | {{yes C}} | style="background:#fff;" | off || style="background:#bbf;" | M | Engaging clutch 2 (C2) and clutch 3 (C3) couples the engine (E) to Motor/Generator A and the ring gear (R). In this mode, the engine is used to assist Motor B, which has primary traction duties, driving the wheels via the coupled sun (S) and pinion gears (P), a reducing gear and differential. |- ! style="font-size:150%;" | (4) | Neutral | frameless|upright=1 | {{no X}} || {{no X}} || {{no X}} | {{maybe|on or off}} | style="background:#fff;" | off || style="background:#fff;" | off | No clutches are engaged, and both Motor/Generator A and Motor B are allowed to freewheel. |- ! style="font-size:150%;" | (5) | Neutral / battery charge | frameless|upright=1 | {{no X}} || {{no X}} || {{yes C}} | {{yes C}} | style="background:#fdb;" | G || style="background:#fff;" | off | Engaging clutch 3 (C3) couples the engine (E) to Motor/Generator A, which operates as a (G)enerator to charge the storage battery. Motor B freewheels. |}
From the patent, the engine provides tractive power only when both clutches C2 and C3 are engaged. For the first-generation Volt and ELR, that occurs in one operating mode (CS2), and in that mode, the engine is considered to assist the electric traction motor (B).
===Generation 2=== The refreshed 2016 Volt featured a 1.5L I4 engine generator that runs on regular, rather than premium gasoline, and an upgraded battery pack with greater capacity of 18.4 kW-hr, giving an estimated {{cvt|52|mi}} of all-electric range per charge, compared to {{cvt|41|mi}} with the first generation Volt.<ref>{{cite news |url=https://www.greencarcongress.com/2015/01/next-gen-chevy-volt-erev-is-more-efficient-with-50-mile-electric-range.html |title=Next-gen Chevy Volt EREV is more efficient, with 50-mile electric range |date=12 January 2015 |work=Green Car Congress |access-date=5 September 2024}}</ref>
thumb|right|Cutaway of second-generation Volt; engine is still on left and drive unit is on right (driver's side). The GM code for the second-generation Voltec powertrain drive unit (transaxle) is 5ET50.<ref>{{cite news |url=https://www.sae.org/news/2014/10/gm-unveils-more-efficient-2016-volt-powertrain |title=GM unveils more efficient 2016 Volt powertrain |first=Lindsay |last=Brooke |date=October 29, 2014 |work=Automotive engineering |access-date=5 September 2024}}</ref> Compared to the first-generation 4ET50/55 transaxles, the overall design has shifted closer to being a parallel hybrid, running more often using mechanical power from the engine supplemented by the electric motors in hybrid mode. A second planetary gear set has been added and the planetary gears are interconnected by coupling the two pinion carriers together, which are coupled in turn to the transaxle output to the final drive differential and wheels. In addition, both electric motors now are used as motors and generators; motor/generator A uses ferrite magnets and has an output of {{cvt|48|kW}} / {{cvt|118|Nm}}, while motor/generator B uses rare earth magnets and has an output of {{cvt|87|kW}} / {{cvt|280|Nm}}.<ref name=GMA-1>{{cite news |url=https://gmauthority.com/blog/2015/02/secrets-of-the-2016-chevrolet-volt-transmission-deep-dive/ |title=Secrets Of The 2016 Chevrolet Volt Transmission: Deep Dive, Pt. 1 |first=Aaron |last=Brzozowski |date=February 20, 2015 |work=GM Authority |access-date=4 September 2024}}</ref><ref name=GMA-2>{{cite news |url=https://gmauthority.com/blog/2015/02/secrets-of-the-2016-chevrolet-volt-transmission-deep-dive-pt2/ |title=Secrets Of The 2016 Chevrolet Volt Transmission: Deep Dive, Pt. 2 |first=Aaron |last=Brzozowski |date=February 21, 2015 |work=GM Authority |access-date=4 September 2024}}</ref> Each motor is smaller than the corresponding motor in the first-generation Voltec, reducing the weight of the transaxle from {{cvt|164|to|119|kg}}.<ref name=GCC-20150423>{{cite news |url=https://www.greencarcongress.com/2015/04/20150423-voltec.html |title=GM provides technical details of the Gen 2 Voltec propulsion system used in the 2016 Volt |date=23 April 2015 |work=Green Car Congress |access-date=4 September 2024}}</ref>
====Operating modes==== The second generation Volt has five different operating modes, two charge-depletion (all-electric), CD1 and CD2, and three charge-sustaining (hybrid), CS1 to CS3. These are:<ref name=GCC-20150423/> * CD1: Motor/Generator B is used for tractive power * CD2: Both Motor/Generators A and B are used for tractive power * CS1: The engine is used for tractive power, assisted by M/G B, with an electrically-variable gear ratio ("low-range" for high power or low speeds) * CS2: The engine is used for tractive power, assisted by M/G B, with a fixed gear ratio (typical driving conditions requiring acceleration) * CS3: The engine is used for tractive power with an electrically-variable gear ratio ("high-range" or "overdrive" for highway cruising)
{|class="wikitable" style="font-size:100%;text-align:left;" |+Voltec (Generation 2) operating modes, from U.S. Patent 8,602,938 B1<ref name=US8602938B1>{{cite patent |country=US |number=8602938B1 |status=Patent |title=Multimode electrically variable transmission having a ferrite magnet motor and method of operating the same |invent1=Brendan M. Conlon |invent2=Khwaja M. Rahman |invent3=Trevor John Blohm |invent4=Sinisa Jurkovic |assign=GM Global Technology Operations LLC |fdate=July 6, 2012 |pubdate=December 10, 2013}}</ref> ! rowspan=2 | Mode !! rowspan=2 | Name !! rowspan=2 | Diagram ! colspan=3 | Clutches !! rowspan=2 | (E)ngine !! colspan=2 | M/G ! rowspan=2 | Description |- ! C1 !! C2 !! C3 ! A !! B |- ! style="font-size:150%;" | CD1 | Single motor (B), electric-only | frameless|upright=1 | {{yes C}} || {{no X}} || {{no X}} | {{no X}} | style="background:#fff;" | off || style="background:#bbf;" | M | Engaging clutch 1 (C1) grounds the first ring gear (R1). Motor B is used as the traction motor. |- ! style="font-size:150%;" | CD2 | Dual motor, electric-only | frameless|upright=1 | {{yes C}} || {{no X}} || {{yes C}} | {{no X}} | style="background:#bbf;" | M || style="background:#bbf;" | M | Engaging clutch 1 (C1) and clutch 3 (C3) grounds both ring gears (R1 and R2). Motor B is used as the primary traction motor, with assistance from Motor A. |- ! style="font-size:150%;" | [CD3] | Single motor (A), electric-only | frameless|upright=1 | {{no X}} || {{no X}} || {{yes C}} | {{no X}} | style="background:#bbf;" | M || style="background:#fff;" | off | Included for completeness as described in the patent, but this mode was not implemented. Engaging clutch 3 (C3) grounds the second ring gear (R2). Motor A is used as the traction motor. |- ! style="font-size:150%;" | CS1 | First (low-range) electrically variable extended-range hybrid | frameless|upright=1 | {{yes C}} || {{no X}} || {{no X}} | {{yes C}} | style="background:#fdb;" | G || style="background:#bbf;" | M | Engaging clutch 1 (C1) grounds the first ring gear (R1). The engine is used for traction, assisted by motor B; A is used as a generator. |- ! style="font-size:150%;" | CS2 | Fixed ratio hybrid | frameless|upright=1 | {{yes C}} || {{yes C}} || {{no X}} | {{yes C}} | style="background:#fff;" | off || style="background:#bbf;" | M | Engaging clutch 2 (C2) couples motor/generator A to the first ring gear (R1) and engaging clutch 1 (C1) grounds the first ring gear (R1), meaning M/G A does not turn. The engine is used for traction, assisted by motor B. |- ! style="font-size:150%;" | CS3 | Second (high-range) electrically variable extended-range hybrid | frameless|upright=1 | {{no X}} || {{yes C}} || {{no X}} | {{yes C}} | style="background:#bbf;" | M || style="background:#fdb;" | G | Engaging clutch 2 (C2) couples motor/generator A to the first ring gear (R1). The engine is used for traction, and B is used as a generator, with A running at variable speeds to proportion engine output between the wheels and generator B. |}
The clutch (C3) on the ring gear of the second planetary gearset (R2) is a one-way clutch, which prevents motor/generator A from turning the engine backward.<ref name=GMA-1/>
====Malibu==== [[File:Voltec Malibu 5ET50 MKE.svg|thumb|right|Stick diagram of 5ET50 (MKE) transmission used with Chevrolet Malibu Hybrid]] The Chevrolet Malibu Hybrid uses the same basic two-motor Voltec drive unit/transaxle design and general layout as the second-generation Volt; however, compared to the Volt, the Malibu Hybrid is not a plug-in hybrid and has a smaller battery. Consequently, the Malibu Hybrid operates in the charge-sustaining (CSx) modes more often, and is fitted with different rotors for its motor/generator units, sharing the same stators as the Volt. The Volt uses ferrite magnets for the rotor in M/G A and rare-earth magnets for the rotor in M/G B, while the Malibu Hybrid has rare-earth magnets for the rotors in both M/G A and B.<ref name=GCC-20160418>{{cite news |url=https://www.greencarcongress.com/2016/04/20160418-malibu.html |title=GM details 2016 Chevrolet Malibu Hybrid powertrain design and operation |date=18 April 2016 |work=Green Car Congress |access-date=5 September 2024}}</ref>
The Malibu Hybrid offers the same three charge sustaining (CS1–CS3) operating modes as the Volt but only one charge draining mode (CD1). The Malibu Hybrid transaxle is designated 5ET50 (MKE), which is similar to the 5ET50 (MKV) used in the Volt, but omits the one-way sprag clutch on the first planetary gearset (labeled as "C3" in the Volt mode diagrams), which makes it impossible to run in two-motor mode (CD2).<ref name=GCC-20160418/>
====CT6==== [[File:Voltec CT6 PHEV.svg|thumb|right|Stick diagram of 4EL70 transmission used with CT6 PHEV]] The Cadillac CT6 PHEV has a front-engine, rear-wheel drive layout which uses a longitudinally-mounted engine and the 4EL70 transmission (RPO MRD)<ref>{{cite magazine |url=https://techlink.mynetworkcontent.com/wp-content/uploads/2017/06/GM_TechLink_09_May_2017.pdf |title=Cadillac CT6 PLUG-IN Delivers Efficient Performance |date=May 2017 |volume=19 |number=9 |magazine=TechLink |access-date=5 September 2024}}</ref> with a driveshaft extending to the rear wheels. The transmission is schematically similar to the 5ET50 transaxle, with an additional planetary gearset and two more clutches, primarily for performance; the output of the two coupled pinion gear carriers (P1 and P2) is coupled to the sun gear of the third planetary gearset (S3), and the pinion gear carrier of the third planetary gearset (P3) provides output to the driveshaft.<ref name=GCC-20160219/> Because the transmission retains the one-way clutch (C3), mode CD2 (dual electric motor operation) is available.
Like the 5ET50 (MKV), Motor/Generator A in the 4EL70 was designed to eliminate the use of rare earth materials; M/G B is related to the traction motor used for the Chevrolet Spark EV.<ref name=GCC-20160219>{{cite news |url=https://www.greencarcongress.com/2016/02/20160219-ct6.html |title=GM's new RWD PHEV system for Cadillac CT6 designed for fun-to-drive high performance as well as efficiency; Volt on steroids |date=19 February 2016 |work=Green Car Congress |access-date=5 September 2024}}</ref>
{|class="wikitable" style="font-size:90%;text-align:center;" |+Voltec (Generation 2) variations ! rowspan=2 {{diagonal split header |Vehicle |Specification}} ! rowspan=2 | Gasoline engine ! colspan=3 | Electric ! rowspan=2 | Combined output ! colspan=3 | Consumption / Economy<ref>{{Fuel Economy Guide |year=2017 |page=38}}</ref> |- ! M/G A !! M/G B !! Battery ! EV !! Hybrid (City/Hwy) !! Electric range |- ! Chevrolet Volt<ref name=GCC-20150423/><ref>{{cite news |url=https://www.caranddriver.com/reviews/a15106092/2016-chevrolet-volt-plug-in-hybrid-test-review/ |title=2016 Chevrolet Volt |first=Aaron |last=Robinson |date=September 11, 2015 |work=Car and Driver |access-date=4 September 2024}}</ref><ref>{{cite web |url=https://www.chevrolet.com/content/dam/chevrolet/na/us/english/index/shopping-tools/download-catalog/02-pdf/2018-chevrolet-volt-catalog.pdf |title=Volt 2018 (brochure) |publisher=Chevrolet |access-date=7 September 2024}}</ref><ref>{{cite web |url=https://www.motortrend.com/reviews/2019-chevrolet-bolt-ev-vs-2019-chevrolet-volt-phev/ |title=2019 Chevrolet Bolt EV vs. 2019 Chevrolet Volt PHEV |first=Billy |last=Rehbock |date=September 30, 2018 |work=Motor Trend |access-date=7 September 2024}}</ref> | 1.5 L ''L3A'' I4<br/>{{cvt|101|hp}}<br/>{{cvt|103|lbft}} | {{cvt|48|kW}}<br/>{{cvt|118|Nm}} || {{cvt|87|kW}}<br/>{{cvt|280|Nm}} | 18.4 kW-hr | {{cvt|149|hp}}<br/>{{cvt|294|lbft}} | {{cvt|106|mpge|kWh/100km}} || {{cvt|43|/|42|mpgUS|l/100km}} | {{cvt|53|mi}} |- ! Chevrolet Malibu Hybrid<ref>{{cite news |url=https://www.caranddriver.com/reviews/a15100616/2016-chevrolet-malibu-hybrid-test-review/ |title=Tested: 2016 Chevrolet Malibu Hybrid |first=Don |last=Sherman |date=June 28, 2016 |work=Car and Driver |access-date=4 September 2024}}</ref> | 1.8 L ''LKN'' I4<br/>{{cvt|122|hp}}<br/>{{cvt|130|lbft}} | {{cvt|55|kW}}<!--<br/>{{cvt|118|Nm}}--> || {{cvt|76|kW}}<br/>{{cvt|306|Nm}} | 1.5 kW-hr | {{cvt|182|hp}}<br/>{{cvt|277|lbft}} | {{N/A}} || {{cvt|49|/|43|mpgUS|l/100km}} | {{N/A}} |- ! Cadillac CT6 PHEV<ref>{{cite news |url=https://www.caranddriver.com/reviews/a15082808/2017-cadillac-ct6-plug-in-hybrid-test-review/ |title=Tested: 2017 Cadillac CT6 Plug-In Hybrid |first=Joey |last=Capparella |date=September 7, 2017 |work=Car and Driver |access-date=4 September 2024}}</ref> | 2.0 L ''LTG'' I4T<br/>{{cvt|265|hp}}<br/>{{cvt|295|lbft}} | {{cvt|74.5|kW}} || {{cvt|74.5|kW}} | 18.4 kW-hr | {{cvt|335|hp}}<br/>{{cvt|432|lbft}} | {{cvt|62|mpge|kWh/100km}} || {{cvt|23|/|29|mpgUS|l/100km}} | {{cvt|31|mi}} |}
==Vehicles==
===Production vehicles, Voltec Generation 1=== <gallery heights=140px widths=210px> File:Chevrolet Volt (4156979107).jpg|Chevrolet Volt (G1) File:2014 Cadillac ELR trimmed.jpg|Cadillac ELR File:Holden Volt (15923957087).jpg|Holden Volt (Australia) File:Motorshow Geneva 2012 - 056.jpg|Opel Ampera (Europe) File:2014 Vauxhall Ampera Positiv CVT 1.4 Front.jpg|Vauxhall Ampera (United Kingdom) </gallery> * Chevrolet Volt (first generation) (sold in Australia, Europe, and the United Kingdom as Holden Volt and Opel/Vauxhall Ampera) * Cadillac ELR
GM chose its Global Delta II compact vehicle architecture for its first Voltec applications. Volt Production began in November 2010 with the first Volts delivered to retail customers in December 2010<ref>{{cite web|url=http://wn.com/NEW_2011_Chevy_Volt__Gearhart_Chevrolet_Delivers_First_Volt_in_America |title=New 2011 Chevy Volt Gearhart Chevrolet Delivers First Volt In America |publisher=Wn.com |date= |accessdate=2012-06-04}}</ref>
===Production vehicles, Voltec Generation 2=== <gallery heights=140px widths=210px> File:Buick Velite 5.jpg|Buick Velite 5 (China) File:2017 Chevrolet Malibu Hybrid, front right.jpg|Chevrolet Malibu Hybrid File:Chevrolet Volt WAS 2017 1739.jpg|Chevrolet Volt (G2) |Cadillac CT6 PHEV </gallery> * Chevrolet Volt (second generation), MY 2016, Plug-In Hybrid; sold in China as the Buick Velite 5 * Chevrolet Malibu Hybrid MY 2016, Hybrid * Cadillac CT6 PHEV, 2017, Plug-In Hybrid
===Concept vehicles=== <gallery heights=140px widths=210px> File:Automobile Cadillac Converj (5463203082).jpg|Cadillac Converj File:Cadillac Provoq NY.jpg|Cadillac Provoq File:Chevy Volt Concept NAIAS 2007 02 (cropped).jpg|Chevrolet Volt (concept) File:Opel Flextreme (front quarter).jpg|Opel Flextreme File:Flickr - plushev - Geneva2010 555.jpg|Opel Flextreme GT/E File:Motorshow Essen 2013-11-30 12-29-46 (11732778764).jpg|Opel Monza Concept
</gallery> * Cadillac Converj * Cadillac Provoq * Opel Flextreme * Opel Flextreme GT/E * Opel Monza Concept
== See also == *List of GM engines *List of GM transmissions *Global Hybrid Cooperation, a two-mode hybrid technology developed in parallel with Voltec by General Motors and partners
==References== {{Reflist}}
{{DEFAULTSORT:Gm Voltec Powertrain}} Voltec Category:Hybrid powertrain Category:General Motors hybrid technologies