Road #2: Hybrid vehicles: Already the widest range of plug-in-hybrids

The Mercedes-Benz plug-in-hybrid initiative is fully under way: following the S 500 e, C 350 e (Saloon, Estate and long version for China), the GLE 500 e 4MATIC and the GLC 350 e 4MATIC, models seven and eight will already be in dealer showrooms by the end of 2016, in the form of the GLC Coupé 350 e 4MATIC and the E 350 e. Mercedes-Benz already has the widest range of plug-in-hybrid models. All in all the hybrid portfolio from Mercedes-Benz presently comprises 13 models. In the E 350 e, the combination of the 9G-TRONIC plug-in-hybrid transmission and the latest generation of electric motors ensures top rankings for fuel consumption, ride comfort and dynamism. The next major technological leap will be made in 2017, starting with the facelift of the S 500 e: for the first time, fully electric operating ranges exceeding 50 km will be made possible by a further development of the lithium-ion battery together with a further optimised, intelligent operating strategy.

Plug-in-hybrids represent a key technology on the road to a locally emission-free future for the car. This is because they offer customers the best of both worlds; in the city they can drive in all-electric mode, while on long journeys they benefit from the combustion engine's range. Hybridisation also makes the internal combustion engine more efficient, and ensures more dynamic performance.

As the strengths of plug-in-hybrids come to the fore in larger vehicles with mixed operating profiles, Mercedes-Benz is opting for this drive concept from the C-Class upwards. The strategic hybrid initiative is decisively facilitated by Mercedes-Benz's intelligent modular hybrid concept: this is scalable to allow it to be transferred to a large number of model series and body versions as well as left and right-hand drive variants.

Latest plug-in-hybrid generation in the Mercedes-Benz E 350 e

The Mercedes-Benz E 350 e will be launched before the end of 2016 with no less than two technological world premieres: the combination of the 9G-TRONIC plug-in-hybrid transmission and the latest generation of electric motors ensures top rankings for fuel consumption, ride comfort and dynamism. The E 350 e is also the first hybrid from Mercedes-Benz with a high trailer towing capacity of up to 2,100 kg.

The third-generation hybrid transmission evolved on the basis of the 9G-TRONIC PLUS automatic transmission. The torque converter, clutch and electric motor are housed in the innovative hybrid drive unit. The remarkably compact design has been achieved by integrating and connecting the clutch, torsional vibration damper and torque converter lock-up clutch within the rotor of the electric motor. The newly developed torque converter with its powerful and highly efficient hydraulic circuit offers the customary outstanding smoothness when pulling away in hybrid mode.

Developed together with Bosch as part of the EM Motive joint venture, the electric motor was specially designed for the 9G-TRONIC plug-in-hybrid transmission. In combination with the likewise new and much more efficient power electronics, it was possible to further increase output and torque to 65 kW and 440 Nm respectively. This is 5 kW more output and 100 Nm more torque compared to the preceding system in the C 350 e. This high level of torque is instantly available from stationary, and allows tremendous agility when pulling away, plus sporty driving characteristics.

Further improvements to the intelligent operating strategy also increase the efficiency of the hybrid. The new thermal management links the vehicle's cooling system with the navigation data, and predictively balances out temperature peaks by advance cooling. The recuperation function was also improved in the E 350 e: energy recovery not only sets in when approaching a slower-moving vehicle, but also before entering speed limits or on downhill gradients. Depending on the driving profile, the business saloon is able to cover 18 up to 33 km with no emissions, consuming just 2.1 litres of fuel per 100 kilometres (NEDC).

Intelligent operating strategy and special comfort and efficiency systems

The innovative hybrid traction head with clutch electric motor and converter in combination with the intelligent operating strategy allows the system to achieve the optimum comfort and efficiency in all driving situations.

  • When the hybrid model is driving fully electrically, the clutch is disengaged while the internal combustion engine is decoupled and switched off.
  • The clutch likewise remains disengaged during energy recuperation, the electric motor then acting as a generator and using the flywheel mass to charge the battery.
  • The clutch is engaged during boost and sailing operation, or in Charge mode, and the intelligent hybrid control system actuates the electric motor according to current power requirements.
  • The clutch remains engaged when driving with the internal combustion engine alone, and the intelligent hybrid control system switches the electric motor to free-running mode.

All the plug-in-hybrids have the following operating modes:

  • Hybrid: All hybrid functions, such as electric mode, boost and recuperation are available and are deployed for optimum fuel efficiency.
  • E-mode: used for all-electric driving – for example in inner-city areas or because the battery holds sufficient charge for the remainder of the journey.
  • E-save: the charge status of the battery is maintained – for example to allow all-electric driving in an environmental zone at a later stage in the journey.
  • Charge: Serves to charge the battery via the combustion engine while on the move, to enable all-electric driving in an environmental zone at a later stage in the journey, for example.

Special functions also improve comfort and efficiency:

  • Silent start: the vehicle starts virtually silently and runs in electric mode. At this point the combustion engine is generally kept switched off.
  • Boosting: The internal combustion engine is assisted with extra output by switching on the electric motor.
  • Energy recuperation: Energy is recovered during braking, and fed to the battery. This energy can then be used at a later stage for electric driving or the boost function.
  • Haptic accelerator pedal: Supports fuel-efficient driving. A resistance point indicates the maximum available electric output. A double impulse signals that the driver should remove their foot from the accelerator pedal in order to switch off the combustion engine and decouple it from the drive train.
  • Intelligent drive management: Intelligent operating strategy for hybrid vehicles, anticipates the course of the road and the traffic situation for maximum efficiency. This includes radar-based recuperation, an anticipatory shifting and operating strategy, a route-based operating strategy and ECO Assist.
  • Pre-entry climate control: The desired interior climate can be set before starting the journey – cooling in the summer, heating in the winter. This function can be activated via a pre-set departure time or via smartphone using the Mercedes me connect app.
  • Retrieval of vehicle status: It is additionally possible to control the charging process or check the charge status and the current electric range via the Mercedes me connect app

 

Enthusiastic: customers testing hybrid vehicles in day-to-day operation

In 2015, with a detailed customer survey, the Customer Research Centre at Mercedes-Benz established what expectations drivers of luxury cars have of hybrid vehicles, and how they assess them in day-to-day operation. 25 customers covering an average annual mileage of 30,000 kilometres were given the opportunity to drive a Mercedes-Benz S 500 in day-to-day use for two weeks. Just under half of these customers had already experienced hybrid models during a test drive or short-term rental, but none of the test subjects, average age 53 years, had any longer day-to-day driving experience with them.

Three interviews were conducted with each of the participants in the study - before vehicle handover, after one week of use and when returning the test car. This enabled the personnel at the Customer Research Centre to evaluate acceptance of plug-in-hybrids over a period of time and depending on use.

These are the major results of the study:

  • The level of satisfaction with all-electric driving is high (in every type and mode of operation), and even tends to increase with day-to-day use.
  • The acceptance of plug-in specific controls and displays is very high.
  • The haptic accelerator pedal is highly appreciated in day-to-day driving.
  • Electric operating range is an important purchase criterion, but after their day-to-day driving experience the participants in the study wished for less range than before.
  • There is time available for charging in the customers' daily routine: after a journey, the car is usually parked in a garage, multi-level car park or public car park for two to four hours.
  • Mercedes me connect is very well received, and the enthusiasm only increases with actual use. The most used functions are the charge indicator, preconditioning and charge status.

Plug-in-hybrids: the success technology of the next decade

During the development of plug-in-hybrids, the engineers at Mercedes-Benz place particular importance on a balance between comfort, spaciousness, weight and electric operating range. With maximum electric ranges of around 30 km, the Mercedes-Benz plug-in-hybrids already routinely cover many day-to-day driving distances under purely electric power, and therefore locally emission-free, and offer their users maximum efficiency and comfort in hybrid operation.

Advances in battery technology are the key to longer electric operating ranges for future plug-in-hybrids and electric vehicles. This is why Daimler AG already began its own development and production of lithium-ion battery systems in 2009. It means that customers directly benefit from the latest developments. Starting with the facelift of the S 500 e, Mercedes-Benz will present the next generation of its plug-in-hybrid technology from 2017.

A further development of the lithium-ion battery will have a rated capacity of up to 13.3 kWh, and in combination with the further improved, intelligent operating strategy this will allow electric operating ranges of over 50 km for the first time. The highly efficient battery system comes from the wholly-owned Daimler subsidiary Deutsche ACCUMOTIVE, which will for the first time also be supplying accumulators for plug-in-hybrids from Mercedes-Benz. It is expected that further progress in battery technology will continue to gradually increase battery capacity and therefore operating range. 

From the C-Class to the S-Class: The current hybrid models

Plug-in-hybrid models are highlighted in light-grey

 

C 350 e1

C 300 h1

GLC 350 e 4MATIC2

Number of cylinders/arrangement

4/in-line

4/in-line

4/in-line

Displacement (cc)

1991

2143

1991

Rated output (kW/hp at rpm)

155 (211) at 5500

150 (204) at 3800

155 (211) at 5500

Rated torque (Nm at rpm)

350 at 1200-4000

500 at 1600-1800

350 at 1200-4000

Rated output of electric motor (kW at rpm)

60 at 2000

20 at 1800

85 at 3.500

Max. rated system output (kW/hp at rpm)

205 (279) at 5000

150 (204) + 20 (27)

235 (320) at 5000

Max. system torque (Nm)

600

500 + 250

560

NEDC fuel consumption (l/100 km) combined

2.1 S

3.6 D

2.5 S

Combined CO2 emissions (g/km)

49

99

59

Efficiency class

A+ (A+)

A+ (A+)

A+

Acceleration 0-100 km/h (s)

5.9 (6.2)

6.4 (6.7)

5.9 (5.9)

Top speed (km/h)

250 (246)

244 (238)

235 (235)

Price from (euros)3

51,051 (52,717)

47,243 (48,909)

52,717 (n.a.)

Figures in brackets for 1Estate, 2Coupé. 3recommended retail price in Germany incl. 19 % VAT. n.a.: not applicable

 

E 350 e

GLE 500 e 4MATIC

Number of cylinders/arrangement

4/in-line

6/V

Displacement (cc)

1991

2996

Rated output (kW/hp at rpm)

155 (211) at 5500

245 (333) at 5250-6000

Rated torque (Nm at rpm)

350

4800 at 1600-4000

Rated output of electric motor (kW at rpm)

65 at 2.250

85 at 3500

Max. rated system output (kW/hp at rpm)

210 (286) at 3800-5500

325 (442) at 5250-5500

Max. system torque (Nm)

550

650

NEDC fuel consumption (l/100 km)

2.1S

3.3 S

Combined CO2 emissions (g/km)

49

78

Efficiency class

A+

A+

Acceleration 0-100 km/h (s)

6.2

5.3

Top speed (km/h)

250

245

Price from (euros)1

n/a

74,196.50 (n.a.)

1recommended retail price in Germany incl. 19 % VAT. n.a.: not applicable

 

 

 

S 300 h1

S 400 h1

S 500 e

Number of cylinders/arrangement

4/in-line

6/V

6/V

Displacement (cc)

2143

3498

2996

Rated output (kW/hp at rpm)

150 (204) at 3800

225 (306) at 6500

245 (333) at 5250-6000

Rated torque (Nm at rpm)

500 at 1600-1800

370 at 3500-5250

480 at 1600-4000

Rated output of electric motor (kW at rpm)

20 at 1800

20 at 1800

85 at 3500

Max. rated system output (kW/hp at rpm)

150 (204) + 20 (27)

225 (306) + 20 (27)

325 (442) at 5250-5500

Max. system torque (Nm)

500 + 250

370 + 250

650 at 1000-4750

NEDC fuel consumption (kg/100 km)

4.3 D

6.0 S

2.8 S

Combined CO2 emissions (g/km)

110

139

65

Efficiency class

A+

A+

A+

Acceleration 0-100 km/h (s)

7.6

6.8

5.2

Top speed (km/h)

240

250

250

Price from (euros)2

87,762.50 (82,229)

93,534 (87,643.50)

110,253.50

1figures in brackets for short-wheelbase versions. 2 Recommended retail price in Germany incl. 19% VAT.

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