Mercedes E-Class Coupe – Slickest production vehicle in the world

Discussion in 'In the News' started by xcel, May 3, 2009.

  1. xcel

    xcel PZEV, there's nothing like it :) Staff Member

    [​IMG] They are not stopping at just the Cd to reduce consumption either!

    [xfloat=right][/xfloat]Wayne Gerdes – CleanMPG – May 2, 2009

    2010 MB E-Class Coupe – I-4 CDI offers up to 46 mpgUS on the NEDC.

    Mercedes-Benz BlueEFFICIENCY - the trademark for an economical Mercedes-Benz passenger car is a package of measures compiled by engineers to reduce weight, aerodynamic drag rolling resistance and enhance engine efficiency.

    Mercedes-Benz's BlueEFFICIENCY is a commitment to reducing fuel consumption and CO2 emissions targets under real world driving.

    For the new E-Class Coupe, MB has developed an extensive number of technologies in order to reduce fuel consumption. From the power steering to the tires, the fuel pump to the alternator and of course improving engine efficiency. Just like hypermiling, the individual measures improve fuel economy by only a percentage point or two, together they add up to a substantial saving.

    Lowest coefficient of drag production car in the world

    Mercedes engineers have succeeded in aerodynamically optimizing the body of the new E-Class, achieving an impressive Cd of just 0.24 making the E-Class Coupe the world's most aerodynamic series-production car.

    To reduce aerodynamic drag, there is an all-new electro-pneumatically controlled grille closure shutter. Its development is based on the knowledge that the air flowing through the radiator and the engine compartment accounts for up to ten percent of a car body's total aerodynamic drag. The fan shutter allows the engine's cooling air quantity to be limited in line with requirements, thus saving fuel. In essence, this means that, when the engine is running under part load and requires relatively little cooling, the radiator grille is closed by a circular system of louvers located behind the radiator. For minimum cooling, the shutter allows just a small amount of residual air to enter the engine compartment, but opens completely when the sensors signal that more cooling air is required.

    When the fan shutter is closed, the Cd falls by 0.013, which is equivalent to a fuel saving of up to 2% when travelling at 80 mph. The fan shutter is fitted as standard on the four-cylinder models and on the E 350 CGI BlueEFFICIENCY Coupe.

    Energy management

    BlueEFFICIENCY involves optimizing the automatic transmission. The newly developed torque converter for the five-speed automatic transmission was designed to reduce hydraulic losses. For the seven-speed automatic transmission in the E 350 CDI BlueEFFICIENCY Coupe, Mercedes has developed Torque converter decoupling which activates when the car is stationary. At a stop, the transmission switches to "N" position so as to reduce the engine load.

    Although the standard power steering system is still based on an all-hydraulic design vs. most moving the an electro-mechanical solution, an intelligent solution helps reduce fuel consumption. Unlike conventional steering systems, in which the power steering pump operates at full power on a permanent basis, the power steering pump in the new Coupe features an additional valve for on-demand control. This means that, when the driver does not require steering assistance, an electronic control unit minimizes the operating power of the power steering pump. The advantage of this system is that less energy from the engine is required to drive the pump.

    The power steering pump is ramped up spontaneously when the driver moves the steering wheel. Even then, the system operates on-demand and adjusts with the current steering speed and vehicle speed to reduce load.

    In order to ensure on-demand energy management, Mercedes is using variable output fuel pumps in all gasoline and diesel engines for the new E-Class Coups. The engine control unit (ECU) only calls for the maximum pump output during full-load operation. In all other driving situations, the pump adapts the delivery volume and pressure in line with the current driving situation, resulting in fuel saving of almost 1% on the (NEDC).

    The E-Class is fitted with newly developed tires whose rolling resistance has been reduced by up to 17 percent without impairing their outstanding handling and braking characteristics.

    Mild Regenerative braking

    Each time a standard car is braked, kinetic energy is converted into heat and goes to waste. The new E-Class Coupe however incorporates an efficient alternator management solution. This means that, whenever the engine is coasting and whenever the vehicle is braked, the voltage level in the vehicle electrical system is increased and the battery is charged. This increased alternator load assists the driver with braking and also helps to recapture some of the braking energy. Conversely, the alternator switches to no-load operation when accelerating or when the battery charge level is high relieving the load on the drive system. This process saves fuel to the tune of around .5 on the highway and up to 1% in a stop/start city environment where coasting and braking are more frequent.

    Included FCD

    Drivers can save fuel on their own aided by a display in the centre of the speedometer, which indicates the current fuel consumption - converted into L/100 Km. With the feedback, drivers are able to adjust their driving style in order to save fuel. In addition to showing this information, the display also advises the driver when to change up a gear (manual models). Driving habits with feedback have shown a savings of up to 15% all by itself further reducing consumption of the MB E-Class Coupe. Do you think these MB engineers have spent more than a few hours here at CleanMPG ;)

    Engine Enhancements

    With its newly developed direct-injection diesel and gasoline engines, Mercedes has taken further steps to reduce both fuel consumption and exhaust emissions - without compromising on agility and driving enjoyment.

    The new four-cylinder diesel engine in the E 250 CDI BlueEFFICIENCY Coupe offers 204 HP and a peak torque of 368 Lb-ft. from the 2.2L turbo-diesel with a 46 mpgUS combined rating on the NEDC.

    In the case of the 1.8L gasoline engine, the E 250 CGI BlueEFFICIENCY Coupe with direct injection has an output 204 HP yet achieves a 32.7 mpgUS combined on the NEDC.

    Diesel engines

    The 2.2L CDI is part of a new series of four-cylinder engines already in its fourth generation. A 29,400 psi injection pressure is a key enabler in raising the engine output while reducing untreated emissions.

    Newly developed piezo injectors are key components allowing precise multiple injections to reduce emissions and fuel consumption plus reduce combustion noise.

    Two-stage turbocharging standard fare

    The new diesel engine in the E 250 CDIBlueEFFICIENCY Coupe debuts MB first two-stage turbocharging.

    Similar to the twin turbo solution on the 335d, the compact module for the new two-stage turbocharger consists of a small high-pressure (HP) turbocharger and a large low-pressure (LP) turbocharger connected in series. At low revs, the low mass, high pressure turbine is doing most of the work. At mid-revs or higher, a transition occurs within the HP turbine’s waste gate is opened and the remaining work is extracted form the LP turbo-charger.

    The benefit of a dual turbocharger system is improved cylinder charging and higher torque even at low revs with the resultant fuel consumption reduced further. In addition, a standard intercooler reduces the temperature of the compressed and heated air by up to 140 degrees C so that a larger volume of air can enter the combustion chambers.

    EGR to reduce NOx

    The newly developed EGR valve works like a rotary disc valve and ensures precise control of the fresh air and recirculated exhaust gas to optimize the quantity of exhaust gas recirculated and induce high recirculation rates. The exhaust gases are cooled as required in a highly efficient heat exchanger with a large cross-sectional area. Together with an HFM (hot-film air-mass sensor) module integrated into the intake air ducting, the setup allows a significant reduction in NOx emissions.

    The combustion air subsequently flows into a distributor which supplies air to each cylinder in a uniform manner.

    Gasoline engines

    MB engineers paid special attention to the engine's warm-up. The new direct-injection gasoline engine features an electronically controlled thermostat to ensure that circulation of the coolant is stopped when the engine is cold. This setup allows the engine oil to heat up quickly and, therefore, minimizes in-engine friction. This intelligent thermal management system is based on driving style, ambient and current coolant temperatures.

    In order to ensure optimum swirl in the Fuel/Air mixture, the CGI engine has intake ports with an adjustable swirl flap to produce high turbulence in low to mid RPM ranges and thus improve the combustion process. The high-pressure fuel pump is driven by the intake camshaft, while a quantity control valve integrated in the pump module ensures on-demand metering of the fuel supply.

    Leanburn V6!

    The new E 350 CGI BlueEFFICIENCY Coupe is powered by the world's first gasoline engine with spray-guided direct injection. Additionally, the E 350 CGI allows a “leanburn” - stratified-charge mode at higher engine speeds than previous implementations.

    MB was the first car manufacturer to introduce spray-guided direct injection into series production. Thanks to higher thermodynamic efficiency, the technology allows lower fuel consumption and exhaust gas emissions. The real benefit of this six-cylinder engine is its stratified-charge mode. The "lean-burn operation" is now at higher engine-speeds and load ranges because the combustion chambers are supplied with fuel several times in succession within a fraction of a second in every combustion cycle, thus vastly improving mixture formation, combustion and consumption.

    With the ever increasing amount of NOx produced during leanburn operation, emissions are controlled by two close-coupled three-way catalytic converters with linear lambda control. MB reduces NOx emissions further by means of two-pipe electrically controlled EGR and by means of two NOx storage catalytic converters on the underbody. During lean-burn operation, these catalytic converters absorb the nitrogen oxides and re-release them in short regeneration phases so that they react chemically to form harmless nitrogen.
    Last edited by a moderator: May 3, 2009

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