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New scalable and modular hybrid drive from MAHLE: MMHP

MAHLE has developed a new, fully integrated and modular hybrid drive that can be tailored to suit a wide range of vehicle applications. The MAHLE Modular Hybrid Powertrain (MMHP) is a fully integrated, plug-in hybrid drive that incorporates a highly efficient 2- or 3-cylinder, turbocharged gasoline engine featuring the latest technologies from MAHLE.

In comparison with established hybrid technologies it is more cost-efficient, more compact, and lighter, MAHLE says.

Modular-powertrain

Modular-powertrain

MAHLE’s new modular hybrid powertrain can be tailored to suit a wide range of applications.


The performance of the electric powertrain used in MMHP reduces the requirements for the combustion engine, enabling the development of a cost-optimized “Dedicated Hybrid Engine (DHE).” The engine concept was designed exclusively for hybrid applications and benefits from the latest innovations made with the passive MAHLE Jet Ignition (MJI) system.

The passive MJI system consists of a small prechamber, which houses a conventional spark plug fitted within the engine’s combustion chamber. It generates hot radical jets, which create a very short combustion event within the engine’s cylinder, thus enabling a high compression ratio and a high exhaust gas recirculation rate, which combined yield reduced fuel consumption.

The use of port fuel injection (PFI), a single overhead camshaft (SOHC) without variable valve timing control, and simple two-valve per-cylinder technology serves to minimize the costs.

The dual-mode hybrid arrangement has been selected for the MMHP, as it combines the best features of both series and parallel hybrid architectures. It allows for flexible vehicle operation, while providing optimal NVH behavior.

When battery SOC is high, the vehicle can operate as a pure EV, whereas when SOC is low and at slow driving speeds it can switch to series hybrid mode. At higher vehicle speeds, however, the combustion engine can be connected directly to the wheels, in a parallel hybrid arrangement.

Mated to a gearbox with customizable transmission ratios, the engine can run flexibly at any given vehicle speed. Options for 1-, 2-, and 4-speed transmissions are available, depending on application requirements. As a result, the fully integrated, electric traction motor is directly connected to the wheels at all times, facilitating uniform performance and a dynamic driving experience with uninterrupted torque delivery.

The motor can also be designed with different power/torque outputs. Coupled with optimized battery sizing, this allows full scalability of the hybrid powertrain for all applications.

The hybrid drive is suitable for a variety of applications—from B-segment through to large J-segment SUVs. The engine itself has achieved ultralow specific fuel consumption figures of 207 grams per kilowatt hour in early stage testing. In the future, fuel consumption of around 195 grams per kilowatt hour in lean operation is realistic by using an active MJI system.

When applied to a compact crossover SUV, WLTP-weighted CO2 emissions are calculated at 18 grams per kilometer. The weight of the hybrid powertrain is similar to a current 4-cylinder gasoline engine with 6-speed manual transmission. The specially designed combustion engine offers potential cost savings of up to 30%.

Comments

GasperG

Wonder how this will work when in hybrid mode, engine is undersized, so it will run at certain constant load, to make a buffer in the battery, this disconnected operation in regards to the gas pedal can be problematic with what people expect from the car.

In SAE paper they are talking about of the 2-cyl. engine with 1.0-L and the 3-cyl. with 1.5-L. It won't be a turbo charged and if it will be "atkinsonized" for efficiency it will be too low power, for something like J-segment SUV.

Other than that, an impressive tech.

GasperG

Now I see it's turbocharged, definitely an interesting and simple design, hope it finds it's way into production soon.

mahonj

"207 grams per kilowatt hour" is very good for "fossil" electricity in a small engine. The best the Irish grid can do is about 200 gms/KwH, when it is running 65% wind energy (the rest is mostly gas).
If this was cheap enough to put into a Focus / Golf sized car, and could be produced in quantity, it would be impressive indeed.
I am not sure how large a battery needs to be used with it - they call it a PHEV (which implies a medium sized battery), but this would push the cost up too much for a Golf / Focus.

gryf

The 207 grams per kilowatt hour " is expected to drop to 195g/kWh in lean operation, helped by Mahle’s Jet Ignition" ref:https://www.sae.org/news/2019/09/mahle-mmhd-hybrid-system. That is diesel engine efficiency and should be attainable based on Mahle's experience in F1 racing.
The article also mentions that the "powertrain with a battery pack giving an 80 km electric range" which is probably similar to the Honda Clarity PHEV range and 17 kWh battery. The real question is the reference to "Weight of the complete hybrid powertrain is similar to that of a current 4-cyl. 2.0-L gasoline engine with manual 6-speed transmission." Does this include the battery? BTW Car and Driver states the weight of the 2020 Ford Escort plug-in hybrid is 585 pounds heavier (battery included).

gryf

The 2020 Ford Escort plug-in hybrid is 585 pounds heavier than the version with the standard 1.5-liter engine (battery included).

SJC

Perhaps you mean Escape.

gryf

That's right SJC.

gryf

Ironically, the 1992 Ford Escort RS Cosworth was a real classic. Also, Mahle Powertrain which is part of Mahle can be traced back to Cosworth. Maybe Ford could steal a page from the past and turn the Ford Focus ST into a 400hp+ AWD PHEV Supercar using this Mahle powertrain with a few extra components, kind of like a low cost Ferrari SF90.

Thomas Pedersen

Re Power train weight:

It probably refers to: ICE+e-motor+gearbox = ICE+gearbox.

207 g/kWh is grams of gasoline, whereas 200 g/kWh in the Irish grid is most likely grams of CO2. 200 g gasoline/kWh = 640 gCO2/kWh.

About this ICE: I have been waiting for years for news like this! Some years back, there were lost of news on this site about simple ICEs to be used for series hybrids or range extenders. But in the mean time, most car makers have opted for their most popular (and expensive) ICEs with twin-turbo, cylinder cut-off, variable valve timing, double overhead camshaft, etc.

This is what is needed; a simple, inexpensive, not-powerful, Millerized ICE, which depends on a battery to deliver transient performance. And no gearbox, please. Either twin-motor series/lockup, or go for broke and make a car which cannot operate below e.g. 20-30 mph on ICE power (only the final gear). Use the weight a space saved for the gearbox to install more batteries.

mahonj

@Thomas, Thanks, that makes more sense: 207 gms of co2 / kwH would be big news indeed.

Engineer-Poet

TP, I have been calling for the hybrid-optimized engine for years as well (many times in these pages).  I doubt anyone was listening, but the need was obvious and Mahle came through.

The jet ignition is an interesting way of solving the problem of slow combustion and consequent low efficiency.  Mazda's Skyactiv uses spark-controlled compression ignition to do much the same thing.

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