Hi from Gordon Haines, originator or the 325iX Registry. I am now driving one of those other German marques, but thought you'd be interested in this comparison.
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Formula 1 technology and design will likely appear in most Mercedes model lines, especially AMG-enhanced variations. Here’s a quote from one of the Mercedes F1 pages:
“While it's difficult to envisage the advanced Hybrid technology of these monstrous F1 beasts trickling down to cars on the road, they are very much helping test and develop the technology of the future - what we'll see in the Hybrid Mercedes-Benz cars and AMG models being driven in years to come.”
So here is my take of a comparison of the current technology of the Mercedes Formula 1 hybrid engine and its transfer to the mild-hybrid vehicles with the new M256 engine. This includes some “450” series vehicles with the “EQ Boost” engine (CLS450)*and the AMG “53” series vehicles with the “EQ Boost+” engine (including my CLS53, the E53 Cabriolet, Coupe and Sedan, and the GT53.) I expect that I have missed or misrepresented some important items — corrections, clarifications and additions are welcome, please.
FORMULA 1
The 2019 F1 1.6 Liter engines use an ERS (Energy Recovery System) which includes an MGU-K (Motor Generator Unit - Kinetic) and MGU-H (Motor Generator Unit - Heat.) Note: the MGU-H will be eliminated in the 2021 engines.
The MGU-K uses a motor/generator in conjunction with a Li-ion battery pack to convert kinetic energy of the vehicle during deceleration and braking into chemical energy stored in the battery. The MGU-K unit is connected to the crankshaft of the engine via a gear set. Maximum rpm of the MGU-K is 50,000 rpm and it can supply an additional 161hp when acting as a motor to augment the turbocharged gasoline engine. Mercedes states that “Each F1 major braking generates enough energy to boil four household kettles (of water.)”
The MGU-H can also charge the LI-ion battery via a motor/generator which is spun by the exhaust and can act in motor mode to spin the turbocharger to eliminate turbo lag. The MGU-H motor/generator is installed between the intake compressor and exhaust turbine sides of the turbocharger. Mercedes calls this an “Electric Turbocharger.” It has a maximum speed of 125,000rpm!
M256 ENGINE with EQ Boost and EQ Boost+
The new 3-Liter straight-6 M256 engines in the mild-hybrid vehicles employ much of the technology and experience from Formula 1 — not necessarily directly, but similar approaches used to yield similar benefits.
Kinetic energy recovery is provided by the flywheel/motor/generator/starter which Mercedes calls an Integrated Starter Generator (ISG). This unit is built by Mitsubishi and is installed between the engine and transmission, the traditional location of the flywheel. It can provide 21hp and 184lb-ft of torque when acting as a motor powered by a 48volt Li-ion battery which is charged by the ISG during deceleration and braking. This hybrid system using the ISG is called “EQ Boost” by Mercedes.
The kinetic energy of the vehicle is converted to stored chemical energy in the 48volt Li-ion battery for later use by the ISG acting as a motor. (See the Footnote on “Regenerative Braking.”
On the AMG version of the M256 “53” series engines there is no “heat recovery” system per se like the MGU-H on the Formula 1 cars. However, in addition to the ISG, there is a unit made by BorgWarner which they call “eBoost.” The hybrid engine with the ISG and this unit is called “EQ Boost+” by Mercedes.
There is an excellent description of the BorgWarner unit at
In Formula 1, the MGU-H motor/generator is installed between the two sides of the turbocharger as described above. However, on our street vehicles, the eBoost unit is a separate, electrically-driven (48volt) compressor/supercharger that forces air into the intake side of the turbocharger to spin it up quickly and to provide additional pressure-boosted air into the intake manifold, primarily at low engine rpm. A bypass valve opens and closes depending on engine speed and throttle position to provide optimal benefits. I have not seen it mentioned in any descriptions, but it seems that this unit would also provide a beneficial vacuum effect on the exhaust turbine side of the turbocharger when it is spun up by the eBoost forced air on the compressor side.
There is an excellent description by AutoWeek of the M256 engine and with its hybrid components at
SUMMARY
I hope this is a reasonably accurate description of these amazing engines and the similarities and differences. Here is another quote from a Mercedes F1 page:
“After all, (F1 is) the perfect training ground, right? Putting this Hybrid technology through its paces at some of the toughest race tracks in the world, at ridiculously-high speeds and in intense conditions. So, while it isn't always obvious, the influence F1 has on the automotive industry is significant and as relevant as it has ever been.”
==========================================
Formula 1 technology and design will likely appear in most Mercedes model lines, especially AMG-enhanced variations. Here’s a quote from one of the Mercedes F1 pages:
“While it's difficult to envisage the advanced Hybrid technology of these monstrous F1 beasts trickling down to cars on the road, they are very much helping test and develop the technology of the future - what we'll see in the Hybrid Mercedes-Benz cars and AMG models being driven in years to come.”
So here is my take of a comparison of the current technology of the Mercedes Formula 1 hybrid engine and its transfer to the mild-hybrid vehicles with the new M256 engine. This includes some “450” series vehicles with the “EQ Boost” engine (CLS450)*and the AMG “53” series vehicles with the “EQ Boost+” engine (including my CLS53, the E53 Cabriolet, Coupe and Sedan, and the GT53.) I expect that I have missed or misrepresented some important items — corrections, clarifications and additions are welcome, please.
FORMULA 1
The 2019 F1 1.6 Liter engines use an ERS (Energy Recovery System) which includes an MGU-K (Motor Generator Unit - Kinetic) and MGU-H (Motor Generator Unit - Heat.) Note: the MGU-H will be eliminated in the 2021 engines.
The MGU-K uses a motor/generator in conjunction with a Li-ion battery pack to convert kinetic energy of the vehicle during deceleration and braking into chemical energy stored in the battery. The MGU-K unit is connected to the crankshaft of the engine via a gear set. Maximum rpm of the MGU-K is 50,000 rpm and it can supply an additional 161hp when acting as a motor to augment the turbocharged gasoline engine. Mercedes states that “Each F1 major braking generates enough energy to boil four household kettles (of water.)”
The MGU-H can also charge the LI-ion battery via a motor/generator which is spun by the exhaust and can act in motor mode to spin the turbocharger to eliminate turbo lag. The MGU-H motor/generator is installed between the intake compressor and exhaust turbine sides of the turbocharger. Mercedes calls this an “Electric Turbocharger.” It has a maximum speed of 125,000rpm!
M256 ENGINE with EQ Boost and EQ Boost+
The new 3-Liter straight-6 M256 engines in the mild-hybrid vehicles employ much of the technology and experience from Formula 1 — not necessarily directly, but similar approaches used to yield similar benefits.
Kinetic energy recovery is provided by the flywheel/motor/generator/starter which Mercedes calls an Integrated Starter Generator (ISG). This unit is built by Mitsubishi and is installed between the engine and transmission, the traditional location of the flywheel. It can provide 21hp and 184lb-ft of torque when acting as a motor powered by a 48volt Li-ion battery which is charged by the ISG during deceleration and braking. This hybrid system using the ISG is called “EQ Boost” by Mercedes.
The kinetic energy of the vehicle is converted to stored chemical energy in the 48volt Li-ion battery for later use by the ISG acting as a motor. (See the Footnote on “Regenerative Braking.”
On the AMG version of the M256 “53” series engines there is no “heat recovery” system per se like the MGU-H on the Formula 1 cars. However, in addition to the ISG, there is a unit made by BorgWarner which they call “eBoost.” The hybrid engine with the ISG and this unit is called “EQ Boost+” by Mercedes.
There is an excellent description of the BorgWarner unit at
In Formula 1, the MGU-H motor/generator is installed between the two sides of the turbocharger as described above. However, on our street vehicles, the eBoost unit is a separate, electrically-driven (48volt) compressor/supercharger that forces air into the intake side of the turbocharger to spin it up quickly and to provide additional pressure-boosted air into the intake manifold, primarily at low engine rpm. A bypass valve opens and closes depending on engine speed and throttle position to provide optimal benefits. I have not seen it mentioned in any descriptions, but it seems that this unit would also provide a beneficial vacuum effect on the exhaust turbine side of the turbocharger when it is spun up by the eBoost forced air on the compressor side.
There is an excellent description by AutoWeek of the M256 engine and with its hybrid components at
SUMMARY
I hope this is a reasonably accurate description of these amazing engines and the similarities and differences. Here is another quote from a Mercedes F1 page:
“After all, (F1 is) the perfect training ground, right? Putting this Hybrid technology through its paces at some of the toughest race tracks in the world, at ridiculously-high speeds and in intense conditions. So, while it isn't always obvious, the influence F1 has on the automotive industry is significant and as relevant as it has ever been.”
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