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Mercedes-Benz introducing diesel E 300 BlueTEC HYBRID with fuel economy of 56 mpg US; gasoline-engined E 400 HYBRID model to follow

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E 300 BlueTEC HYBRID Click to enlarge.

Mercedes-Benz is introducing the new E 300 BlueTEC HYBRID; the luxury-class diesel hybrid offers fuel consumption of 4.2 L of diesel/100 km (56 mpg US), with CO2 emissions of 109 g/km. (Earlier post.) The E 300 BlueTEC HYBRID is based on the E 250 CDI, yet has a higher output and approximately 15% lower fuel consumption.

This diesel hybrid will be available in the European market as a Saloon and Estate from the third quarter 2012. Daimler will introduce the Mercedes-Benz E 400 HYBRID—equipped with a V6 gasoline engine—into in the US market, and later in other countries such as Japan and China. In 2009, Mercedes-Benz introduced the S 400 HYBRID. (Earlier post.)

Modular hybrid technology opens up the way for us to rapidly add hybrid models to other model series. With a clear focus on the varying needs of the worldwide markets, we are able to offer precisely the models that our customers require.

—Professor Dr. Thomas Weber, the member of the Daimler Executive Board for Group Research and Head of Mercedes-Benz Cars Development

Engine 4-cyl. in-line diesel
Displacement 2143 cc
Rated output 150 kW/204 hp
Torque 500 N·m
Transmission 7G-tronic PLUS
Battery Li-ion
Battery output/capacity 19 kW/0.8 kWh
Motor output 20 kW
Motor torque 250 N·m
Electric range 1 km
Motor torque 250 N·m
eDrive/Sailing 35/160 km/h

The modular hybrid concept requires no modifications to the bodyshell; the hybrid module can be used flexibly in other model series and there will be right-hand drive versions apart from the diesel and gasoline models.

In the E 300 BlueTEC HYBRID, Mercedes-Benz has combined the 2.2-liter, four-cylinder diesel engine developing 150 kW (204 hp) and 250 N·m (184 lb-ft) torque with an electric motor rated at 20 kW and 250 N·m.The hybrid drive unit is a further development of the module from the S 400 HYBRID and is based on the 7G-TRONIC PLUS automatic transmission. Features include omission of the hydraulic torque converter and the addition of a wet clutch of the kind also found in the high-performance AMG models.

Consequently, the electric motor can be integrated in the transmission unit in such a way that it takes up only 65 mm more space than the 7G-TRONIC. The omission of the converter allows all-electric motoring as well as sailing, thus significantly boosting the potential to reduce fuel consumption.

The compact electric motor, which is installed in space-saving configuration in the clutch housing between engine and transmission, is a 3-phase AC internal rotor magneto motor which generates a maximum output of 20 kW and peak torque of 250 N·m at an operating voltage of 120 volts.

The motor assists the diesel engine when the car is accelerating (boost effect) and, in alternator mode, is used for the recuperation of braking energy, although it is also suitable for driving under electric power alone.

In combination with a 19 kW, 0.8 kWh lithium-ion battery pack, the modular hybrid system requires little installation space and weighs around 100 kg. The space-saving installation of the battery pack in the engine compartment in place of the conventional starter battery means that the interior dimensions and the luggage compartment capacity remain unchanged. In addition to serving as an energy accumulator for the electric motor, the lithium-ion battery is also connected via the voltage converter to the 12V on-board electrical system, which supplies power to standard power-consuming devices such as the headlamps and the comfort features.

The internal combustion engine can be switched off when coasting on the overrun at speeds up to 160 km/h (99 mph), since ancillaries such as the steering, brakes and refrigerant compressor operate electrically. It is restarted quickly, smoothly and virtually silently. Sailing is possible at speeds below 160 km/h. The combustion engine shuts down and the desired speed is maintained by the electric‑motor alone until the battery needs recharging.

Electrical power alone is used for moving off and driving under low load. Acceleration from standstill is particularly powerful, since the electric motor's full torque of up to 250 Nm is immediately available. The electric motor supports the combustion engine during acceleration, e.g. when overtaking.

The E-Class hybrid can run on electric power alone at speeds up to 35 km/h (22 mph) and for up to one kilometer (0.62 mile). In most cases the car uses electric power alone for maneuvering and parking.

When the car is being driven at a constant speed, the engine control unit shifts the operating points towards low specific fuel consumption levels. When the car is coasting (decelerating on the overrun), the electric motor acts as a generator. When the brake pedal is depressed, the generator output is initially increased proportionally for greater deceleration. Only when increased brake pressure is applied are the wheel brakes also operated.

The central display provides information on the current energy flow and the charge status of the battery.

On the road, the E 300 BlueTEC HYBRID is comparable to the E 300 CDI (170 kW/540 N·m),but with around 35% lower fuel consumption and CO2 emissions. In terms of vehicle weight too, the E 300 BlueTEC HYBRID is on a par with the E 300 CDI.

Mercedes-Benz says that the E 300 BlueTEC HYBRID will receive an environmental certificate according to ISO standard TR 14062 from the neutral examiners at TÜV Süd in time for market launch.



Great car, good design, they have combined the IMA with diesel, but with enough motor power to do more. I would like to see more battery capacity for better regenerative braking, but that is not necessary. The size is right and the mileage is excellent.


Looks like a Sonata. How many does it cost?


A 2012 gas E300 MSRP is $48-%56K. The hybrid will be a wee bit more. At least the 1% will have good gas mileage. Maybe a C class will follow in a couple of years.


This is a lot like a Camry HEV with a diesel ICE instead of the 2.5 L gasoline ICE offered by Toyota. The 56 mpg is outstanding due to the use of diesel ICE.


Very impressive - lets hope it is not too expensive.

Also,over the years, it would be nice if they could increase the battery capacity to give a little more e-driving.
and/or reduce the price.

@SJC - I do not think you need a larger battery for engine regenerative braking - 0.8kwH should be enough.

A larger battery for further e-driving would be another thing ...

Nick Lyons

This diesel hybrid will be available in the European market as a Saloon and Estate from the third quarter 2012. Daimler will introduce the Mercedes-Benz E 400 HYBRID—equipped with a V6 gasoline engine—into in the US market...

No diesel hybrid for USA, I guess (not that I could afford it).

Roger Pham

This is better than the Camry hybrid because no trunk space is lost. OEM conversion kits for existing vehicles shouldbe next.


With a small battery, it depends on state of charge, if you are trying to put 20 kW quickly into a .8 kWh battery with 80% SOC, I don't think you get much regenerative braking.

Roger Pham

0.8 kWh battery is quite small for the size of the vehicle. 1.6 kWh would be optimal, however, I think that they try to fit this 0.8 kWh Lithium battery into the existing slot of the former lead-acid battery. A bigger battery, or additional battery capacity, can be placed in the place of the spare tire for better hybrid performance and gas saving. Even limited PHEV is possible with this approach, like the Prius PHEV.

Modern cars with tire pressure warning system does not really need a spare tire. A small tire inflator with pressure gauge placed in the trunk, with optional leak sealant for larger leaks, would suffice. Because of modern tire pressure warning system, most of the time, the driver can drive the car to the shop and have it repaired without having to change the tire in the street, which can be very hazardous.


I agree, putting it where they did limited size, but heat is an issue just as it is with permanent magnet motors. Engineering is a trade off and it looks like they made some good decisions with this one.


This is essentially the BAS-II evolution I suggested earlier, minus the larger battery.  No surprises, it was obvious given the way tech is going.

Cable runs to the trunk and connectors for removable expanded battery packs are an obvious upgrade path.  Want the cargo space?  Unplug the expanded pack and put it in the garage.  Safety could be handled by contactors at the forward end and in the expansion battery to de-energize the cabling for handling.  Energizing the contactors could be done via a separate low-voltage power and communications circuit.


"The compact electric motor, which is installed in space-saving configuration in the clutch housing between engine and transmission"

It sound more like an IMA than it does a BAS, but that is not worth arguing about. They did a good job IMO and I hope it sells well.


The form factor of the motor isn't terribly important, nor is its technology (though induction motors avoid the rare-earth magnet issue).  I detailed the notion here.

Roger Pham

Honda's IMA scheme has the motor permanently linked to the engine and cannot enable all-electric operation without the engine also turning along, creating unnecessary engine friction. The IMA scheme further requires a torque converter to allow the engine to idle while the vehicle is standing still.

The BAS-II evolution has a conventional GM-style BAS (Belted Alternator-Starter) to start the engine or to generate electricity from the engine, furthermore having a second electric motor connected to the transmission and separated from the engine by a clutch. The second motor acts as torque converter, allowing the engine to idle or to run the vehicle at low speeds without mechanical linkage to the vehicle.
This enables all-electric operation in which the engine is completely stopped.
This further enables serial hybrid mode at low speeds, in which the engine powers the alternator which feeds electricity to the motor.
At higher speeds, the engine is clutched directly to the transmission and the motor, now functioning similar to Honda's IMA scheme.

Sorry, E-P, I wrote this before I saw your detailed notion.


So, it is possible to make a diesel hybrid after all...


It is nice to see a European manufacturer building a hybrid.
Most of the development in Europe is diesel and downsizing.


Diesels and downsizing is what makes life so difficult for hybrids in Europe.


An interesting comparison would be the Peugeot 508 hybrid vs. the Mercedes. Both cars are roughly the same size but the hybrid systems are totally different. Peugeot offers 4WD as an advantage but the performance of the Mercedes is probably much better. FC is fairly similar, i.e. 4.1 l/100 km for the Peugeot and 4.2 l/100 km for the Mercedes. Maybe someone on this forum can find the time to do a thorough comparison.



"furthermore having a second electric motor connected to the transmission and separated from the engine by a clutch. The second motor acts as torque converter, allowing the engine to idle or to run the vehicle at low speeds without mechanical linkage to the vehicle."

I see no mention of a "second electric motor" in this design nor BAS.


The AWD capability of the Peugeot 508H is an advantage. However, both cars will cost about 2x to 2.5X times the Camry hybrid or a Camry Hybrid + a Leaf.



Yes it apparently is possible. If you look at the earlier posts back to 2008, you will see the previous design evolved into this, which was what some of the respondents commented on.


Roger Pham

What you've described is the second motor that is attached to the transmission. The first motor(/generator/starter) is attached to the engine to start it up and then to generate electricity when the vehicle is standing still. This allows the second motor to act as a torque converter to allow the car to start from zero speed without requiring any mechanical connection to the engine.

Just because the article did not mention the first motor does not mean that it is not there.
BAS is E-P suggestion base on GM mild hybrid. If you don't want to use a belt-drive to connect the engine to the first motor, then you can use a thin but large-diameter rim-type of motor co-axial with the engine crankshaft, like in the Honda IMA design, to also double as a flywheel as well.


I'm pretty sure Mercedes S 400 Hybrid (on which this hybrid system here is based) does NOT have another starter, but uses the ISG for everything (start, torque boost, as generator, for regen braking). Additional starter, as you suggested may be used in recent Hyundai/Kia hybrids (not sure). With just one motor they need to finely control clutch slip when restarting engine, when car is moving on electric power, especially when accelerating - it's tricky.
I think that BMW uses almost identical system in their ActiveHybrid models - supposedly ZF supplies the hybrid system for both makers.


Consider my comment as an ironic joke. About 10 years ago, I made extensive computer simulations that proved the technical viability of diesel hybrids. Under comparable conditions, the relative improvement of fuel economy was 25 and 20% for gasoline and diesel (parallel) hybrids, respectively. Although the relative (and absolute) improvement is smaller for diesels, it is still substantial. However, many car manufacturers have said that the incremental cost for diesel hybrids would be prohibitively high. Therefore, it is nice to see that someone has enough faith in the concept to introduce it on the market. I hope it will be a success!

Roger Pham

How can you be so sure that the MB S400 Hybrid has no starter?

Without a dedicated starter, the engine must be started by the clutch using the car's kinetic energy, meaning a very noticeable jerk will be felt every time the engine is started. This is a no no in a luxurious make like MB.

Or, the single motor can be de-clutched from the transmission, comes to a stop, clutched to the engine via another clutch, starts the engine, and then clutched back to the transmission...This type of delay in power delivery is a no no in a high-end performance model. The customer wants instant power delivery when stepping down on the gas pedal.

Furthermore, with only one motor, you will need two clutches, one between the engine and the motor, and another one between the motor and the transmission.
You save yourself the cost and weight of a smallish 5-kW starter-alternator but in return you need a second clutch, between the motor and the transmission that will probably cost not a whole lot less nor weighing any less than a 5-kW starter, while losing a lot of advantages like engine-starting smoothness and rapid power delivery. The 5-kW starter-alternator can also give the engine more torque boost if needed, beside the 20-kW main motor.

The starter-alternator can be mounted right onto the crankshaft and serving also as a flywheel, thus incurring no weight nor space penalty, and causing no friction nor reliability issue like in a BAS design.

In a hot summer day in slow traffic, the A/C will consume a lot of power, needing the engine to stay on to deliver that power to the A/C compressor, meaning that you will need a dedicated engine-mounted alternator to supply that extra electrical power while the car inches along in congested traffic. Otherwise, the battery will get depleted quickly, got over-heated, and can't get re-charged if the car only inches along at 5mph...how can you run the engine fast enough at 5 mph while supplying enough electricity to the A/C compressor motor? if you only have one single motor/generator churning at 5mph car speed even in lowest gear?

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