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Mitsubishi Electric begins mass-producing first crankshaft-mounted ISG system for 48V hybrids; used in Mercedes-Benz vehicles

Mitsubishi Electric Corporation has begun mass-producing the auto industry’s first crankshaft-mounted integrated starter-generator (ISG) system for 48V hybrid vehicles, which will be mounted in Mercedes-Benz vehicles. The system will be on display during 45th Tokyo Motor Show 2017.

Belt-driven system ISG systems use a belt to transfer power from the motor to the engine; this, said Mitsubishi, can limit both maximum torque with abrupt force transmission and the motor’s peak power output. By contrast, connecting the motor directly to the engine crankshaft eliminates the limitations of the belt system and enhances both motor output power and power generation.

The demand for 48V hybrid vehicles, which offer excellent fuel efficiency at relatively affordable costs, is expected to increase, especially in Europe. Mitsubishi Electric developed its ISG system—a crankshaft direct-driven system for idling-stop-start, energy recovery and torque assist—to achieve higher output power and better fuel efficiency in 48V hybrid vehicles.

Mitsubishi Electric said it will continue to develop increasingly smaller, lighter-weight and higher-power ISG systems to increase fuel efficiency and reduce CO2 emissions.


Compared to belt-driven starter-generators, the crankshaft-mounted motor produces higher output power and generates more power, which contribute to better fuel efficiency.

Mitsubishi Electric’s original coil winding technology realizes a high-density configuration for thick coils required in a 48V high-current motor. The thin-profile, higher-power motors adapt flexibly to various vehicle layouts.

A newly developed transfer-molded power module for 48V systems reduces heat resistance and enhances durability. The optimally designed cooling unit enhances cooling performance to realize a compact, highly reliable inverter.


Juan Valdez

Bolt this sucker to every gasser and we'd bankrupt big oil !!

This is great tech, basically bolting an electric motor to the gas engine. Assuming this includes a beefy 48v battery, then fuel economy, esp in cities can go way up. If you make it a plug-in hybrid, depending on the battery size, you can drive most days on pure electricity.



@Juan Valdez All of this could have been done in the late 1990s. No political will to address pollution and global warming.


The electronics weren't there in the 90's.  Today we've got SiC coming to market at power densities silicon never could match.

This thing isn't going to bankrupt OPEC either.  It'll eke out 5-10% through idle-stop and minimizing accessory drag.  You won't be able to put enough power through it to do much all-electric driving; for that you need a much higher system voltage able to carry 50+ and ideally 100+ horsepower, not 15 tops.

IMO the real impact is going to come from what it allows the engine designers to do.  The engine doesn't have to idle, can have considerable lag in throttle response, and can use the battery as both an energy source and energy sink.  A turbocharger with an alternator instead of a wastegate and maybe electric supercharger lets the engine be downsized with no sacrifice of power; the electric system compensates for turbo lag and allows excess turbo-alternator output to be applied to the crankshaft.


Can anyone imagine the added complexity and reduced space under the bonnet?
Just go electric with the newer solid state batteries.


While it still needs a combustion engine in anything bigger than a 'town car or motorcycle it is a better design than belt drive.
Simplifies adoption of various 48V systems steering water pumps etc.

Below hazardous (~50V) voltage systems do not require the same level of certification will allow stepped industry transitioning to high voltage systems for both workshops and personnel. It takes time for tradespeople to upskill and for those with a working understanding to pass that on through the workforce.

Citaro bus specs:

"The electric power generated by recuperation is stored in a bank of supercapacitors. These electricity storage units are characterized by a high power density. They are resistant to high power peaks and have a long life. Unlike batteries, supercaps are ideally suited to the continuous quick changeover between charging and discharging that occurs when stopping and pulling away again in typical city bus operation. Braking to a stop from a speed of 50 km/h just once is enough to recharge the power storage units in the Citaro hybrid.

The power storage unit assembly in the Citaro hybrid is made up of two modules, with each module containing 16 supercaps. The two modules together have a total capacity of 2 Ah and are mounted in a space-saving location at the back of the roof.

It generates a maximum output of 14 kW (17.36hp) and 220 N·m of peak torque."

Can anyone imagine the added complexity and reduced space under the bonnet?

Don't imagine it, go look.  There are plenty of such vehicles in showrooms.  See for yourself.  It's not much at all.

Just go electric with the newer solid state batteries.

Asking people to go buy what is for sale exactly nowhere.  Are you employed by OPEC?

Simplifies adoption of various 48V systems steering water pumps etc.

"etc." including air conditioning.  That is very big in many places.  Getting rid of the engine-driven pump also allows elimination of the flexible hoses to the engine and the compressor shaft seal, which are the three main avenues of leakage for A/C refrigerant.  As these refrigerants are often strong GHGs, turning the A/C system from a regular maintenance item into a lifetime-of-vehicle piece is going to be pretty big.


General Motors EV1 was from 1996 to 1999. Of course the electronic was there.


The EV1 electronics were bulky, cost too much and weren't reliable enough.  SiC is many times tougher, especially on the heat tolerance, and allows radical shrinkage of the total package.


A reduction of about 4% to 7% in fuel consumption with a 48 Volts HEV system is not enough to offset the increase in fuel consumption due to the large increase in heavier SUVs and Pick-Ups sales.

Toyota's excellent 50 mpg Camry Hybrid and 55 mpgs Prius Hybrid are much better choices.

Many existing PHEVs will do even better at an added cost?

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