Cars • Gasoline engineEngine 275Initial trainingInformation moduleAs at 03/03Contents04.03.2003Page Title1Engine 275 - an overview8Engine mechanics M275 / M28516ME 2.7.1 fuel-injection and ignition system26Fuel system30Exhaust gas turbocharging49Comparison of exhaust gas turbocharger and mechanical supercharger53Exhaust-gas system54ECI ignition system62Information unit engine 285Engine 275 - an overview 04.03.2003P00.00-2256-50P00.00-2821-50P00.00-3081-50Highlights M275The new V12 with bi-turbo chargingHigh-tech perfection is promised by the new 12-cylinder engine, which will be available as of autumn2002 in the model refined S-Class. This V12-cylinder bi-turbo comes with commanding performancevalues: the engine develops a rated output of 368 kW at 5,000 rpm and a rated torque of 800 Nm at1,800-3,500 rpm.This power unit has a generously rated surplus in output and, in particular, torque and this is available atconstantly harmonious output and torque development. In keeping with the character of a luxury sedanthe new motorization comes with a perfectly smooth operation and an harmonic noise design.GT01_00_0016_C71Taking all viewpoints into consideration the technical realization of the goals set called for a V12-conceptwith 5.5 l displacement, 60 degree cylinder bank angle and bi-turbo charging.Engine breathing is supported by a turbocharger with "wastegate-control system" for each cylinder bank.Exhaust gas turbocharging development mainly focuses on the finest response characteristics incombination with the achievement of maximum torque at as low as possible engine speed. Apart fromthis special emphasis was placed on the acoustic characteristic.Output and torque in abundanceIn comparison to the predecessor engine the rated output and rated torque for the new engine have beenincreased by approx. 30 % or 50 %. Because a corresponding increase in displacement was ruled out dueto the wish to keep to moderate fuel consumption and a compact design, a slightly reduced displacementwith two exhaust gas turbochargers and charge air cooling was selected. The model refined S-Classachieves thus outstanding performance with excellent acoustics, a superb degree of vibrational comfortand, in view of the performance data, adequate fuel consumption.Smooth operation and noise emissionOn a 12-cylinder engine with a cylinder angle of 60 degrees, all forces and torques of the 2nd order arecompletely balanced as a matter of principle. Thus the greatest possible degree of smooth operationwithout additional balance shafts is a given factor.All engine parts are designed using ultramodern calculation and testing methods in terms of rigidity andvibrational characteristics. The improvement in vibrational characteristics is contributed to in particularby a bedplate design with gray cast iron inserts on the crankshaft main bearings. The oil pan iscompletely decoupled from the crankcase in terms of vibrations. Combustion noise is dampened by theinstalled dual ignition, which serves to keep the pressure gradients in the combustion chamber at a lowlevel and which minimizes cycle scatter for each individual combustion procedure. Noise reduction wasalso achieved by the damping through the exhaust gas turbochargers on the air and exhaust-gas sides aswell as the water jacket of the water-cooled generator.GT01_00_0017_C71WeightDespite the additional exhaust gas turbocharger, engine-side charge air cooler and the reinforced beltdrive the M275 only weighs 270 kg and thus achieves an excellent power/weight ratio of 0.65 kg/kW.The following lightweight components are used:∗cylinder head cover made of die-cast magnesium∗weight-optimized cracked, forged steel conrod∗die-cast aluminum for upper and lower section of crankcase∗lightweight silitec cylinder liner∗weight-optimized elastoval piston∗ a 3-valve design with one camshaft per cylinder bank∗weight-optimized crankshaft and dynamic balancer∗an oil pan made of die-cast aluminumTechnical data comparisonSales designation CL 600CL 600S 600SL 600 * Vehicle model215.378215.376220.176230.476 Engine model137.970275.950Cylinder arrangement / number / angle V12 / 60°Valves / spark plugs per cylinder 3 / 2Continuous fuel-injection and ignition system ME 2.7ME 2.7.1Turbocharging with charge air cooler (intercooler)Air supply Naturally aspiratedengineTotal displacement cm³5,7865,513Rated output kW (hp) at rpm270 (367) at 5,500368 (500) at 5,000Rated torque Nm at rpm530 at 4,100800 at 1,800 - 3,50013.414.7Fuel consumption (New European Driving Cycle)Super Plus l/100 km/hAcceleration 0 - 100 km/h s 6.3 4.8* Market launch 04/2003Performance graph M137Performance graph M275P01.00-2341-73GT01_00_0018_C73Comparison of M275 / M285 with M137Engine 137 (ME 2.7)Engine 275 / Engine 285 (ME 2.7.1)AdvantageECI ignition system (AC voltage ignition system with integrated ionic current measurement), ignition voltage 30 kV, two spark plugs per cylinder ECI ignition system (AC voltage ignition system withintegrated ionic current measurement), ignitionvoltage 32 kV, two spark plugs per cylinderImprove ignition performance and reliabilityNo knock sensors, recognition of knocking combustion by using the ionic current measurement 4 knock sensors¾A29/1 and A29/2 on left cylinder bank¾A30/1 and A30/2 on right cylinder bankRecongition of knocking ignition over the knocksensors offers the availability of an optimally gradedperformance map for the monitoring of smoothoperationNaturally aspirated engine One exhaust gas turbocharger (bi-turbo) made ofsteel casting for each cylinder bank.Enormous generation of power for a relatively low fuel consumptionFuel pump is drived by fixed12V À constant delivery volume Fuel pump (max. delivery rate approx. 245 l/h) isdrived by PWM signal (control by a fuel pump controlmodule) À deliver according to demand¾Less wear and noise¾Saves energyA total of 8 O2 sensors for in front of and behind the four firewall catalytic converters respectively A total of 4 O2 sensors, 2 in front of and 2 behindthe firewall catalytic converters respectivelyReduction of the number of componentsFulfillment of Euro 4 and LEV 1Cylinder Shut Off: the left row of firing cylinders areshut-off when idling or when running in a low loading situation -----Priority is given to obtaining a performanceadvantageCamshaft adjustment-----DittoDetection of combustion misfires through ionic current signals Detection of combustion misfires through ioniccurrent signals and through smooth operationevaluation using crankshaft position sensor (L5)Optimize the combustion misfiring detection to suitturbocharged engineEngine mechanics M275 / M28504.03.2003 Crankcase The crankcase and oil pan for the M137, M275 and M285 engines are designed as follows.Legend:1Upper crankcase section made of die-castaluminum2Weight-optimized crankshaft and dynamicbalancer3Upper crankcase section made of die-castaluminum4Rubber gasket between crankcase bottomsection and upper section of oil pan5Upper section of oil pan made of die-castaluminum6Oil pan bottom section made of die-castaluminumP01.40-2029-09 The upper section of the oil pan in the S-Class is designed as shown. The front axle design of the variousvehicle models (S-, SL-Class and Maybach) means that the oil sumps have to be located in different places.Service tipThe following must be noted when removing and installing the upper oil pan:A copper connecting link is located at one of the screws, which serves to set up the ground connectionbetween the oil sensor and the crankcase.Never forget this when assembling!GT03_00_0001_C71The oil pan constriction on the M275 consists of two parts. This has a positive effect on the sealingconcept.The upper part of the oil pan is sealed against the lower part of the oil pan using a silicone sealantSpare Part No. A 002 989 73 202/50 ml.The upper part of the oil pan is sealed against the crankcase by means of a rubber seal which is vibrationdampening and also serves to optimize noise generation.Aluminum crankcase with gray cast-iron insertA genuine highlight is the particularly innovative design of the crankcase.The crankcase is of a two piece bedplate design. Massive gray cast iron inserts in the area of the lowercrankcase section's main bearing achieve improved noise generation characteristics.The very compact design of the crankcase does not lead to any increase in the size of the enginecompared to previous models despite turbocharging. This, together with the light-weight constructiontechnology used, leads to a total engine weight of just 270 kg which represents an increase in weight ofjust 50 kg compared to the basic M137 engine.The increase in weight is due to the additional coolant compressor and the extraordinarily powerful 350 Aalternator.GT03_20_0005_C01In order to meet the demands of higher heat and pressure loads, the wall between the cylinders of theupper crankcase section have been widened compared with the M137 by 2 mm to 8 mm and in eachcase 3 water cooling bores (1 and 2) have been integrated into the walls.The cylinder bore has been reduced compared with the M137 from 84.0 mm to 82.0 mm. By contrast thecylinder spacing of 90 mm and the stroke of 87 mm have not been altered.Water-cooling bores (1 and 2) for cooling wallsGT03_20_0006_C011The cylinder liners are made up of an alloy of aluminum-silicon (silitec). They have a wall thickness of2.5 mm.Advantage:¾lower cylinder thermal distortion¾lower noise and less pollutant emissions¾lower weight and greater dimensional stability.GT03_20_0007_C01Piston The cast pistons and piston ring are designed to cope with the extremely high pressures andtemperatures. For the realization of the smallest, noise-relevant plays and for the purpose of improvingthe emergency running characteristics, the gravity die-cast pistons have been galvanically coated withiron.The piston pins have been optimized in accordance with the acting loads both in terms of outer diameterand wall thickness.Piston cooling is supported by oil spray nozzles.2Connecting rodForged steel conrods made of crack-capable forged steel are used. To protect the extremely high loadsDaimlerChrysler is using a high-strength forged material for the first time.As previously with the 137 engine for reasons of higher dimensional accuracy in the M275 and M285engines the lower connecting rod eye is cracked (broken) and bolted to the crankshaft's main bearing.GT_03_10_0003_C01Cylinder headThe aluminum cylinder heads come with the 3-valves-per-cylinder technology familiar from the M137.Each cylinder bank contains a camshaft, which actuates both the inlet and exhaust valves by means ofcam followers.The M275 and M285 engines do not need camshaft adjustment, as their torque increasing function incombination with turbocharging is rendered superfluous.Chain driveCamshaft drive ensues from the crankshaft by means of a twin roller chain. A sprocket wheel is used inthe V-center for deflection purposes. Otherwise the chain is routed through slightly bent slide rails.The chain tensioning force is achieved over a tensioning rail by means of a hydraulic chain tensioner.In order to improve the noise characteristic of the chain drive, the sprocket wheel of the crankshaft, theguide wheel and the camshaft are rubberized.To optimize the overall length the oil pump drive has been located downstream of the timing chain. Theoil pump chain drive is designed as a single roller chain.GT_01_30_0016_C01Engine control How is the engine control's basic adjustment made?The basic adjustment is 30° ATDC. At 30° ATDC the groove (6) of the camshaft at left and right iscentered relative to the separating surface for the cylinder head cover towards the inner-V. To fasten thecamshafts, the special tool familiar from the M137 can be used. The groove on the crankshaft gear (2)points to the mark on the crankcase. The guide wheel (3) without a mark need not be considered.1Copper plated connecting link, two each for camshaft sprocket adjustment2Groove in crankshaft3Guide wheel without mark4Mark on camshaft sprocket at right R5Mark on camshaft sprocket at left L6Groove in camshaftP05.10-2144-06Crankcase ventilation of M275/M285The blow-by gas is aspirated by the vacuum in the charge air distribution pipe, or turbocharger intake pipe.It is routed from the timing-chain compartment to the centrifugal oil separator where the oil is separated from the blow-by gas.Following this, the blow-by gas is routed to the pressure regulating valve. The separated oil is fed back to the oil pan over the timing-chain compartment.Partial load ventilationDuring partial load ventilation the air is routed across the check valve into the charge air distribution pipe.Full load ventilationDuring full load ventilation the partial load ventilation line is closed by the boost pressure applied to the check valve. The air separated from the oil is then routed to the Turbocharger intake pipe downstream of the air cleaner.GT18000003C81Pressure regulating valveCharge air distribution pipeTurbocharger intake pipe Check valve,full load ventilationCentrifugal oil separatorCheck valve,partial load ventillationOil separator/Pressure regulating valveA centrifugal oil separator integrated into the ventilation system of the engine on the left-hand camshaftachieves excellent removal of oil under all operating conditions.An additional pressure regulating valve ensures that there is adequate vacuum in the crankcase duringthe air inlet suction and turbocharging processes as well as under conditions of partial loading and fullloading.At a specific vacuum (> 50 mbar) in the turbocharger intake pipe the connection to the crankcase issealed by means of a diaphragm in the pressure regulator valve.If the pressure in the crankcase rises above a specific value, the diaphragm is opened and thus theconnection to the turbocharger intake pipe set up again.GT_01_30_0017_C71ME2.7.1 fuel-injection and ignition system04.03.2003Motor electronics control module 2.7.1The electronic engine management is an advanced development of the ME 2.7 of the M137. It includesthe engine control function including all diagnoses and is networked over the CAN-C databus with furtherelectronics. The control module is housed in a ventilated electronic module box along with otherelectronics.The engine control function has been adapted to the bi-turbo engine:∗The pressure in the charge air distribution pipe and the corresponding temperature are recorded forcalculation of the aspirated air mass using separate pressure and temperature sensors.∗The boost pressure is recorded by a second pressure sensor upstream of the throttle valve and servesthe boost pressure control.∗Boost pressure is regulated by the wastegate valve in the exhaust gas turbocharger.P07.08-2017-01∗Torque momentum coordination and the engine's emergency (limp-home) function have been adaptedto the turbocharger-specific requirements.∗The diagnosis has been extended by the charger protection feature, which serves to prevent anyimpermissibly high turbine wheel speed.∗The signals from 4 knock sensors are evaluated for knock identification.∗The ionic current misfiring detection familiar from the 137 engine has been adapted to suit therequirements of a highly-supercharged engine. The detection quality was able to be improved bycontinuously comparing it with a speed uniformity analysis on the crankshaft.∗In order to safeguard the exhaust gas turbocharger and the three way catalytic converters against toohigh exhaust gas temperatures, a model-based exhaust gas temperature control has been introduced.∗The communication of ME control module with the alternator via a bi-serial communication interface.E ngine fuse and relay box (K40/8)I n the engine compartment the S and CL 600 models have had an additional relay box installed. The following components are contained in this relay box:K40/8kW Charge air cooler recirculationpumpK40/8kVMotronic relayK40/8kX Intank fuel pump relay(only for S 55 AMG, CL 55 AMG)F use 87Motronic 1F use 88Motronic 2F use 89reserve P20.00-2118-04 F use 90Charge air cooler recirculationpumpF use 91reserveK40/8C ontinuous fuel injection system (overview)B OSCH M E 1.0M119M120∗Control through hot film mass air flow sensorM E 2.0M112M113∗Control through hot film mass air flow sensorM E 2.1M111∗Control through hot film mass air flow sensorM E 2.7 M E 2.7.1 M E 2.7.1M137M285M275∗Control through hot film mass air flow sensor∗Pressure motor control∗Pressure motor controlM E 2.8M112M113∗Control through hot film mass air flow sensor M anifold air pressure sensor for monitoringM E 2.8.1M112 MLM113 ML∗Pressure motor controlV DO M SM M166∗To 08/2001 control through hot film mass air flow sensor∗As of 09/2001 pressure motor controlS iemens S IM4M111 EVO∗To speed 2,000 rpm control through hot film mass air flow sensor∗As of speed 2,000 rpm manifold air pressure controlLocation of the components on the M275/285 engine71Check valve (purge control)B28/7Pressure sensor downstream ofthrottle valve actuatorN91ECI power supply unitN92/1ECI Ignition module for right cylinderbankN92/2ECI Ignition module for left cylinderbankY31/5Boost pressure control pressuretransducerY32Air pump switchover valveY101Divert air switchover valveP07.61-2735-06Location of the components5/1Charge air cooler (left bank)5/2Charge air cooler (right bank)121/1Air cleaner (left bank)121/2Air cleaner (right bank)B17/8Charge air temperature sensorB28/4Pressure sensor downstream of aircleaner on left cylinder bankB28/5Pressure sensor downstream of aircleaner on right cylinder bankB28/6Pressure sensor upstream of throttlevalve actuatorM16/6Throttle valve actuatorN91ECI power supply unitP07.61-2729-06Location of the componentsB6/2Camshaft Hall sensor (left bank)B6/3Camshaft Hall sensor (right bank)L5Crankshaft position sensorP07.61-2731-06Location of the components126/1Air injection shutoff valve on left bank(combination valve: check valveintegrated)126/2Air injection shutoff valve on rightbank (combination valve: check valveintegrated)B11/4Engine coolant temperature sensorB40Oil sensorM33Electrical secondary air injectionpump(illustration shows the 275 engine,on vehicle side for the 285 engine)P07.61-2734-06Location of the componentsA29/1Front knock sensor (left bank)A29/2Rear knock sensor (left bank)A30/1Front knock sensor (right bank)A30/2Rear knock sensor (right bank)G2AlternatorP07.61-2730-06Location of the componentsG3/3x1Plug connector for O2 sensor(upstream of left catalytic converter)G3/4x1Plug connector for O2 sensor(upstream of right catalyticconverter)B Test connection for divert air valveP07.61-2732-06Location of the components110/1Turbocharger intake pipe110/4Divert air valve110/6Charge air pipe110a Exhaust gas turbocharger (left)110b Exhaust gas turbocharger (right)B Exhaust gasD Fresh gas (after air cleaner)E charge airP07.61-2733-06Fuel system04.03.2003GeneralIn order to prevent any increase in temperature in the fuel tank caused by the heated-up fuel return flow,vehicles with the 275 and M285 engines also have the fuel system designed as an induction system.The fuel pump (M3) draws in the fuel from the fuel tank and pumps it through the modified fuelfilter (55/1) with integrated overflow valve to the injection valves on the fuel distribution tube.The fuel supply is assumed by the tried-and-tested helical spindle pump, which had to be modifiedhowever, because of the higher fuel requirements of the engines at full load.New is the electronic control of the fuel pump (M3), which regulates the delivery volume depending onthe engine's instantaneous fuel requirements. This in turn serves to enhance the pump's noise and wearcharacteristics.Pressure controlPressure control is set up via the fuel pressure sensor (B4/7), which is installed in the admission linedownstream of the fuel filter (55/1) and which converts the fuel pressure into a voltage signal. Thisvoltage signal is evaluated in the fuel pump control module (N118). A pulse width modulated signal(operating voltage) is used to regulate the speed of the fuel pump (M3) such that the system pressure ofapprox. 3.8 bar is held constant.If the system pressure drops, e.g. below approx. 3.7 bar, the delivery volume (rotational speed) of the fuelpump is increased until such time as the system pressure is reached again.At the maximum power consumption of the fuel pump of approx. 16 A (coupling on fuel pressuresensor (B4/7) detached), a fuel pressure of approx. 9 bar is reached.M3N11855/1B4/7Fuel supply system55/1Fuel filter (55/1) withintegrated overflow valve B4/7Fuel pressure sensorM3Fuel pumpN118Fuel pump control module1Housing upper part2Electronic board3Coil4Armature5Housing lower part with hose connections 6Electrical connectiona Groundb SignalcVoltage supply (5 V)P47.20-2103-06 Design and functionThe fuel pressure sensor (B4/7) consists of a coil (3), a movable armature (4) and an electronicsystem (2).As fuel pressure increases, the armature in the coil is moved, the inductivity (magnetic field) alters. This isregistered by the electronic system and sent as a signal to the fuel pump control module (N118)(approx. 0.5 V at 0 bar; approx. 4.5 V at 9 bar).The voltage supply for the fuel pressure sensor is set up by way of the fuel pump control module.Fuel pressure sensor (B4/7)Fuel filterThe fuel filter (55/1) with integrated overflow valve is designed for the new pressure control for theengines. In other words, the overflow valve opens slightly at a system pressure of approx. 3.8 bar (releasepressure for overflow valve approx. 3.5 bar). The throttled return flow of the overflow valve leads back tothe fuel tank (75) and supplies the suction jet pump for the purpose of charging the swirl pot in the fueltank.After switching off the engine, the overflow valve assumes the task of a check valve and closes theadmission line to the fuel tank and thus holds the system at a specific pressure (holding pressure).Fuel pump control moduleGeneralThe fuel pump control module (N118) consists of the control system, electronic circuit and a wiringharness, which leads to the fuel pressure sensor (B4/7) and the fuse and relay module.The voltage supply of the fuel pump control module is set up by way of the fuel pump relay.Task of the fuel pump control moduleTo maintain the fuel system pressure, operation of fuel pump (M3) is synchronized over a PWM signalwith the aid of the signal from the fuel pressure sensor (B4/7). If the control module for the fuel pumpdetects a drop in the system pressure over the signal from the fuel pressure sensor actuation goes on forlonger triggered the PWM signal and this maintains the system pressure (3.8 bar)GT_47_00_0002_C01Advantages of electronically regulated fuel supply∗ Temperature reduction of fuel return ∗ Lower noise emission∗ Relay function can be implemented.∗ Relief to on-board electrical system of up to 40 %∗ Extended fuel pump service life ∗ Pressure and volume flows can be regulated according to a desired performance map.∗ Starting pressure and volumetric flow can be regulated (start-time optimization)∗ Fuel saving up to 0.15 l/100 km∗ Constant supply of ancillary assemblies (e.g. suction jet pumps)∗ Pollutant reduction∗Extended change interval for fuel filter (lifetime)GT47_00_0005_C75Overflow valveClosed-loop controlEngine fuel railScrew-type fuel pumpQ max = 245 - 260 l/h at 4 barVoltage supplyFilterFuel tankFuel pump control moduleExhaust gas turbocharging 04.03.2003In comparison to the predecessor engine M137, the rated output and rated torque for the new engine 275 have been increased by approx. 30 % or 50 %.Because a corresponding increase in displacement was ruled out due to the wish to keep to a moderate fuel consumption, a compact design and due to expected impairments in comfort, a slightly reduced displacement with charging with two exhaust gas turbochargers and charge air cooling was selected.The usual camshaft adjustment as found in the other engines, which in particular serves to boost the pulling power in the lower speed range has been dispensed with. The bi-turbo charging aspirates the twelve-cylinder engine so effectively that the driver can call up the tremendous power reserves even at very low speed.In figures:At 1,000 rpm there are already 500 Newton meters of torque on call, at 1,500 rpm the 600Newton meter barrier is broken through and as from 1,800 rpm the engine achieves its maximum torque which is for car production engines of 800 Newton meters, which remains constant at 3,500 rpm.Basic function of exhaust gas turbocharged engineCharge air coolerEngine/CylinderExhaust gas turbochargerFunctionGeneralOne exhaust gas turbocharger each (110a, 110b)with wastegate control per cylinder bank supportsthe engine's fresh air supply.In doing so the turbine wheel in the exhaust gasturbocharger is driven by the exhaust flow (B).Fresh air (D) is routed over the turbochargerintake pipe (110/1) to the intake side of theexhaust gas turbocharger. The compressor wheel,which is mounted by means of a common shaft tothe turbine wheel, compresses the fresh air. Thecharge air (E) is routed via the charge airpipe (110/6) to the engine.Monitoring and control max. charger speedTo limit the maximum charger speed, thepressure ratio downstream/upstream of thecompressor (pressure value of B28/6 to B28/4and B28/5) is calculated and regulated by themap-dependent boost pressure control.P07.61-2733-06Air route of turbocharged engine5/1Charge air cooler for left cylinder bank5/2Charge air cooler for right cylinder bank12Intake manifold (charge air distributionpipe)110a Left exhaust gas turbocharger110b Right exhaust gas turbocharger110/1 Intake line/air cleaner housing(Turbocharger intake pipe)110/6Boost pressure (charge air) pipe110/7Hose piece with hose clamp110/8Y-connecting piece121/1Air cleaner for left cylinder bank121/2Air cleaner for right cylinder bankM16/6Throttle valve actuatorB ExhaustD Clean air (downstream of air cleaner)E Charge airP09.40-2063-06。
