3V Engine
07-02-2010, 06:43 PM
#1
Burning Brakes
Thread Starter
07-02-2010, 10:36 PM
#3
Burning Brakes
Thread Starter
07-02-2010, 11:23 PM
#4
Le Mans Master
As I recall, 3V was big talk in the days leading up to C6. I suppose at the time it was thought not to be worth the additional complexity.
What do you think are the odds that this time around it'll reach production?
What do you think are the odds that this time around it'll reach production?
07-03-2010, 11:23 AM
#5
Burning Brakes
Thread Starter
Hayman, Alan W. (Romeo, MI, US)
Rozario, Frederick J. (Fenton, MI, US)
Patterson, Gary J. (Utica, MI, US)
Mazzola, James J. (DRYDEN, MI, US)
Sczomak, David P. (Troy, MI, US)
that, to me, look like the Gen V small block. Just go here
http://www.freepatentsonline.com
and type in, in quotes, "general motors" and then either one of these last names or something like engine or valves. Just download the .pdf files. If you look through the many patents from these guys, it's really hard to not conclude that Gen V will use three values per cylinder and a high pressure direct injection system. Patents related to 3V engine have been coming out of GM for a long time and as recently as 2008 and 2009. So, I can't say for sure that Gen V is a 3V engine but it sure looks like that is the way they are heading. GM's issue seems to be an inability to execute plans, so, who knows ...
Incidentally, the auto industry must start to try and incorporate more magnesium into their cars. I would think that C7 is a perfect showcase for mass reduction via magnesium. Whatever it is, it won't be huge but it would probably far exceed the largest current application. A tremendous amount of effort has been made to get magnesium ready for automotive applications. I don't think the status of titanium has changed much. Even though this new Armstrong process appears to be up and running, it's probably too early to see a reduction in titanium prices.
http://www.itponline.com/index_files...gBrochure1.pdf
The other two things that I am curious about with regard to C7 is the transmission and the window material. Eight-speed automatics with special launching features seems to be what C7 needs. GM has a staggering array of patents on transmission similar to this. Again, there is an issue of GM being able to execute.
Maybe I'm off here but it doesn't look like Exatec has been able to get their glazing technology into too many cars as windows. There's a huge weight savings to be had.
And now that the aluminum frame doesn't have the design constraint of being interchangeable with the steel frame, I expect C7 to have a better aluminum frame.
As you drive up the thermal efficiency of the engine through direct injection, more of the chemical energy from the fuel goes to the flywheel instead of the engine coolant. This means that the 440+hp 5.5L engine will not require as much cooling as a Gen IV engine. In ideal circumstances, nearly 40% of the fuel's energy content will reach the flywheel. Combine that with cylinder deactivation and VVT, the Gen V engine should be a significant step forward from the LS3.
07-10-2010, 11:11 AM
#6
I never understood GM not bringing the new Duramax 4.5L diesel to market in the 2010 trucks/SUVs. All of the development work was done, parts sourced, manufacturing plant picked out...and then the bankruptcy hit and the engine was killed. They would have killed Ford/Dodge/Toyota/Nissan in the ½-ton truck market. It's almost as if they misunderstand the word execute in "execute plans"...they think it means "kill" as in kill the plan.
07-10-2010, 02:52 PM
#7
Le Mans Master
3V: sounds possible, if not likely. Maybe direct injection isn't enough of a boost on its own to compensate for the rumored smaller displacement, and maybe fancier breathing helps make that smaller displacement feel bigger by getting more out of it across the rev range. OTOH, GM seems reluctant to add cost and complexity to the engine it puts in its cost-conscious sporting and hauling machinery. If they can meet short-term efficiency targets without it, GM is not above leaving new technology on the bench until it's a goal down in the second half.
Magnesium: it's already in the frame for the coupes' top. Can magnesium wheels still provide useful weight savings for a road car? That's another easy option; I wonder if the economics have improved since Corvette last tried it. Maybe the hatchback frame? Beyond that it gets trickier, doesn't it? Have other manufacturers done mixed magnesium-aluminum chassis?
On the subject of structural elements, A-pillars seem to be too thick already, and rollover strength is the current chant of the safety nannies -- might we see higher-strength steel here? Weight seems less important than size here.
Polycarbonate windows: That was floated for the C6 Z06 hatchback but never came to pass. Nobody likes windows that aren't clear; is anything scratch-resistant enough to be acceptable to consumers yet? Are Corvette buyers ready to accept it? Maybe the next Z06? Or maybe that's what the split window talk is about?
Aluminum frame: tantalizing, but I'm afraid to get my hopes up on account of, you know, GM's cheapness. Have we really reached the point where it's worth the hassle and expense? Or can steel, perhaps better steel, still make a case for itself?
As for diesel, there was that brief period when some thought it might go mainstream, justifying its cost in efficiency. But then the economy tanked, and gas prices and climate change weren't the scariest monsters under the bed anymore. Maybe in a couple of years our fears will shift and the wheels will again turn for a light-duty diesel. I doubt it will ever make sense under a Corvette's hood, though.
.Jinx
Magnesium: it's already in the frame for the coupes' top. Can magnesium wheels still provide useful weight savings for a road car? That's another easy option; I wonder if the economics have improved since Corvette last tried it. Maybe the hatchback frame? Beyond that it gets trickier, doesn't it? Have other manufacturers done mixed magnesium-aluminum chassis?
On the subject of structural elements, A-pillars seem to be too thick already, and rollover strength is the current chant of the safety nannies -- might we see higher-strength steel here? Weight seems less important than size here.
Polycarbonate windows: That was floated for the C6 Z06 hatchback but never came to pass. Nobody likes windows that aren't clear; is anything scratch-resistant enough to be acceptable to consumers yet? Are Corvette buyers ready to accept it? Maybe the next Z06? Or maybe that's what the split window talk is about?
Aluminum frame: tantalizing, but I'm afraid to get my hopes up on account of, you know, GM's cheapness. Have we really reached the point where it's worth the hassle and expense? Or can steel, perhaps better steel, still make a case for itself?
As for diesel, there was that brief period when some thought it might go mainstream, justifying its cost in efficiency. But then the economy tanked, and gas prices and climate change weren't the scariest monsters under the bed anymore. Maybe in a couple of years our fears will shift and the wheels will again turn for a light-duty diesel. I doubt it will ever make sense under a Corvette's hood, though.
.Jinx
07-13-2010, 09:48 AM
#8
Burning Brakes
Thread Starter
3V: sounds possible, if not likely. Maybe direct injection isn't enough of a boost on its own to compensate for the rumored smaller displacement, and maybe fancier breathing helps make that smaller displacement feel bigger by getting more out of it across the rev range. OTOH, GM seems reluctant to add cost and complexity to the engine it puts in its cost-conscious sporting and hauling machinery. If they can meet short-term efficiency targets without it, GM is not above leaving new technology on the bench until it's a goal down in the second half.
Magnesium: it's already in the frame for the coupes' top. Can magnesium wheels still provide useful weight savings for a road car? That's another easy option; I wonder if the economics have improved since Corvette last tried it. Maybe the hatchback frame? Beyond that it gets trickier, doesn't it? Have other manufacturers done mixed magnesium-aluminum chassis?
On the subject of structural elements, A-pillars seem to be too thick already, and rollover strength is the current chant of the safety nannies -- might we see higher-strength steel here? Weight seems less important than size here.
Polycarbonate windows: That was floated for the C6 Z06 hatchback but never came to pass. Nobody likes windows that aren't clear; is anything scratch-resistant enough to be acceptable to consumers yet? Are Corvette buyers ready to accept it? Maybe the next Z06? Or maybe that's what the split window talk is about?
Aluminum frame: tantalizing, but I'm afraid to get my hopes up on account of, you know, GM's cheapness. Have we really reached the point where it's worth the hassle and expense? Or can steel, perhaps better steel, still make a case for itself?
As for diesel, there was that brief period when some thought it might go mainstream, justifying its cost in efficiency. But then the economy tanked, and gas prices and climate change weren't the scariest monsters under the bed anymore. Maybe in a couple of years our fears will shift and the wheels will again turn for a light-duty diesel. I doubt it will ever make sense under a Corvette's hood, though.
.Jinx
Magnesium: it's already in the frame for the coupes' top. Can magnesium wheels still provide useful weight savings for a road car? That's another easy option; I wonder if the economics have improved since Corvette last tried it. Maybe the hatchback frame? Beyond that it gets trickier, doesn't it? Have other manufacturers done mixed magnesium-aluminum chassis?
On the subject of structural elements, A-pillars seem to be too thick already, and rollover strength is the current chant of the safety nannies -- might we see higher-strength steel here? Weight seems less important than size here.
Polycarbonate windows: That was floated for the C6 Z06 hatchback but never came to pass. Nobody likes windows that aren't clear; is anything scratch-resistant enough to be acceptable to consumers yet? Are Corvette buyers ready to accept it? Maybe the next Z06? Or maybe that's what the split window talk is about?
Aluminum frame: tantalizing, but I'm afraid to get my hopes up on account of, you know, GM's cheapness. Have we really reached the point where it's worth the hassle and expense? Or can steel, perhaps better steel, still make a case for itself?
As for diesel, there was that brief period when some thought it might go mainstream, justifying its cost in efficiency. But then the economy tanked, and gas prices and climate change weren't the scariest monsters under the bed anymore. Maybe in a couple of years our fears will shift and the wheels will again turn for a light-duty diesel. I doubt it will ever make sense under a Corvette's hood, though.
.Jinx
C7 would be the perfect showcase for the magnesium-intensive car. The link in another thread shows potential applications. Which ones are chosen is beyond me. To me, doors seem like a good place.
Polycarbonate glazing has a lot of potential. It seemed like Exatec had solved all of the problems with this but I still don't see it getting used.
Improved mileage is going to be driven principally by drivetrain efficiency and vehicle mass. Dropping mass is getting much more important with more strict CAFE standards in the near future. I don't think a mass produced aluminum frame for C7 must be dramatically more expensive than a steel frame. For drivetrain efficiency, a transmission must not only have small energy losses but also must respect the fact that the engine thermal efficiency is a function of at least RPM and loading.
My understanding is that the highest thermal efficiency that we are likely to see in passenger cars would come from an HCCI. However, that looks like it is far off in the future.
I've said this before but GM is caught between the customer and the government. The ONLY way to satisfy both masters is to get improved technology (to maintain or improve performance and creature comforts) into the upcoming vehicles without raising prices too much. All of this will conspire to force C7 to be an impressive car.
07-13-2010, 08:27 PM
#9
Drifting
Member Since: Feb 2002
Location: Chapel Hill NC
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This is how MB did it
I am NOT, repeat NOT proposing dual overhead cams and four valves for the Corvette. I AM showing what might be GM's combustion process. With the exception of the turbos, every other technology MB uses can be applied to the push rod V8! 
"New V-Engine Generation from Mercedes-Benz Feature 3rd Generation Gasoline Direct Injection and New Operating Modes for More Power and Torque and Lower Fuel Consumption
Mercedes-Benz is introducing its newly developed V-series (V6 and V8) engines. The new V engines offer more power and torque, and 22-24% lower fuel consumption than their predecessors.
Mercedes-Benz has achieved this increase in efficiency through the use of a technology package that incorporates third-generation direct gasoline injection with spray-guided combustion, multiple injection and multi-spark ignition; new operating modes; the use of a new start/stop function as standard; and other features.
Both the new V6 and the new V8 from Mercedes-Benz have aluminium crankcases, pistons and cylinder heads. The crankshaft, connecting rods and valves are of special forged steel. The technology package in the new engine generation includes a number of new developments:
In combination with multi-spark ignition, a further developed, third-generation gasoline direct injection system with spray-guided combustion and piezo-electric injectors offers further possibilities for fuel savings—in the V8 by means of an improved, homogeneous combustion process, and in the V6 by a new, stratified combustion process with a considerably extended characteristic map and fuel-efficient lean-burn technology.
In conjunction with start/stop technology, shift point adjustment and specific friction-reducing measures, improvements in day-to-day fuel consumption by more than 20% are possible.
Power consumption by ancillary units has been reduced. These include an optimized water pump with 2nd-generation thermal management, a demand-controlled oil pump, a volume-controlled high-pressure fuel pump and an intelligent generator management system.
Lightweight construction techniques and detailed improvements have also reduced in-engine friction considerably compared to the previous engine.
Direct injection system. The system pressure is up to 200 bar, the pressure being variably optimized according to the engine’s characteristic map. Completely newly developed piezo-electric injectors allow up to five injections per intake stroke for optimal mixture formation.
The piezo-electric injector has a response time of 0.1 milliseconds, allowing the fuel injection to be very sensitively and precisely adjusted to the current load and engine speed, with a beneficial effect on emissions, fuel consumption and combustion noise.
The multiple injections even in tiny quantities made possible with piezo-electric injection technology were used by Mercedes-Benz engineers to control a wider characteristic map with the efficient lean-burn process, and to provide the conditions for further functions.
New operating modes. As the first new operating mode, Mercedes-Benz engineers have developed “Homogeneous stratified combustion” (HOS). HOS is a combination of homogeneous lean-burn and classic stratified combustion. The first injection is sprayed into the intake stroke, forming a homogeneous basic mixture. Actual stratified injection takes place during the compression stroke before ignition, and is a single or double injection depending on the characteristic map.
Another new operating mode is known as “Homogeneous Split” (HSP). In this homogeneous combustion process, more than 95% of the fuel is singly or multiply injected, followed a very small ignition injection to stabilize combustion. This is used when combustion conditions are difficult.
The characteristic map of the new Mercedes-Benz V6 engine is therefore basically divided into up to four areas:
idling range (homogeneous)
low partial load up to 4 bar and 3800 rpm (stratified)
medium partial load 4 to 8 bar and up to 4000 rpm (HOS)
high load and entire engine speed range (homogeneous or HSP)
The V8 engine is operated homogeneously over the entire characteristic map, but under high load homogeneous or HSP operation is used to improve smooth running characteristics.
Multi-spark ignition. The third-generation direct injection system also features rapid multi-spark ignition (MSI). Following the first spark discharge and a brief combustion period, the coil is rapidly recharged and a further spark is discharged. The MSI system enables up to four sparks to be discharged in rapid succession within one millisecond, creating a plasma with a larger spatial expansion than conventional ignition.
Controlling this rapid multi-spark ignition enables both the time lapse before the next spark and the combustion duration for the relevant operating point to be optimally adjusted. This provides scope for optimizing the centre of combustion and improving residual gas compatibility, especially during stratified charge operation. Fuel consumption can be reduced by roughly 2% in this way.
Fuel savings of up to 4% are possible alone by the use of piezo-electric injection technology in combination with multi-spark ignition, depending on the driving cycle.
Cylinder head with new camshaft adjuster. On the basis of the previous engine’s architecture, Mercedes-Benz engineers developed the variable, hydraulic vane-type camshaft adjusters for the intake and exhaust sides. These now have a larger adjustment range of 40 degrees with reference to the crankshaft.
They were also able to improve the functionality, achieving a 35% greater adjustment speed and adjustability at an oil pressure as low as 0.44 bar. Despite the better performance, this new development features significantly smaller dimensions and low weight. For this reason the installation space on the longitudinal and vertical axes of the engine was able to be reduced by around 15 millimeters.
Two-stage chain drive for low noise. The extreme compactness of the camshaft adjusters was achieved by the new, two-stage chain drive. This drives short secondary chains—one per cylinder bank—via a primary chain and an intermediate gear. All three chains can be individually adjusted via a chain tensioner. This results in low tensioning forces and low chain dynamics, ensuring consistent timing and outstanding acoustic properties, with friction reduced even further. The new chain drive is compact and ensures low-noise operation.
Controlled oil pump with two pressure stages. A fourth chain drives a likewise completely newly developed, variable vane-type oil pump. The operates with two pressure stages, depending on the characteristic map. At low engine speeds and loads the pump runs at a low pressure of two bar. At this time the oil-spray nozzles for piston cooling are switched off. The high-pressure stage is activated at the upper load and engine speed levels. With this control concept, the lubrication and cooling points of the engine can be supplied with significantly lower drive energy than would be possible with an uncontrolled pump.
New coolant ducting and 3-phase thermal management. The coolant ducting in the cylinder head is also completely new. The water mantle is of two-piece construction to improve flow. This leads to specific increases in flow speeds and heat dissipation at certain points, accompanied by a reduction in pressure throughout the coolant circuit. This has made it possible to reduce the power output of the water pump despite an increased engine output.
As it warms up, the flow of coolant is regulated by a 3-phase thermal management system so that it rapidly reaches normal operating temperature. Initially the coolant remains at rest in the engine. It then circulates in the engine circuit, but without the radiator. When a temperature of 105 °C has been reached in normal operation (87 °C under high load), the vehicle’s radiator is included in the circuit. The water supply to the interior heating system is separately controllable.
Component weights have also been reduced by the concerted replacement of aluminium and steel by plastics, e.g. for the thermostat, belt pulley, wheel, heater valve and hydraulic lines.
Start/stop function with direct-start. The new start/stop system operates with starter-supported direct-start. This means that when the engine is switched off, the attitude of the crankshaft is registered by a new crankshaft sensor so that the engine control unit knows the positions of the individual pistons. On restarting, it can then select the cylinder that has the most suitable piston position for first ignition. After the starter has briefly turned over the engine, reliable injection, ignition and combustion is immediately possible.
Minimized friction. Particular attention was paid to reduced friction in both engines. This was primarily achieved by a reduction in flow through the oil and water pumps, low-friction pistons, piston rings and cylinder walls, plus the new thermal management system and chain drive.
Modularization. The new Mercedes-Benz engine family is based on modularization. It allows the use of a stop-start function, 4MATIC all-wheel drive and combination with a hybrid module. The new Mercedes-Benz V-engine generation will initially be used as an 8-cylinder in the CL-Class, and later in the S-Class from autumn 2010.
V8. On the basis of its predecessor, the new V8 has undergone significant further development. It has a 15-percent smaller displacement (4663 cc rather than 5461 cc) but generates 320 kW (435 hp) and therefore around 12 percent more output than the preceding unit (285 kW/388 hp). Whereas the current CL 500 consumes 12.3 liters per 100 kilometers (19 mpg US), this figure drops to 9.5 liters (25 mpg US) with the new engine—a reduction of 22%.
CO2 emissions have likewise fallen by 22%, from 288 g/km to 224 g/km. At the same time torque has been raised from 530 N·m to 700 N·m (32%). The high maximum torque is already available from 1800 rpm.
In the new V8, Mercedes-Benz engineers primarily achieved a high output for a lower displacement by using two turbochargers—one for each bank of cylinders. The intake air is forced into the eight combustion chambers at an overpressure of up to 0.9 bar, with the turbine blades rotating at up to 150,000 rpm. The turbochargers and their hot gas ducting are accommodated on the outsides of the cylinder heads. This enabled the intercooler module with its air/water intercooler and charge-air distributor to be located inside the V of the engine.
The chargers were configured to provide high torque even at low engine speeds—compared to the previous engine the result is an increase of more than 40% at 2000 rpm. 600 N·m is available between 1600 and 4750 rpm.
The engine is based on a further development of the previous engine’s die cast aluminium crankcase with cast-in aluminium/silicon (Silitec) cylinder liners. Basic and connecting rod journal diameters were adopted from the preceding engine, while for load reasons the piston compression height was raised by just under four millimeters. By reducing the lift and shortening the connecting rod by 2 millimeters, it was possible to retain the interior height of the crankcase.
V6. The new V6 engine is naturally aspirated, and has the potential for future use of a turbocharger due to the modular design concept. The most striking change between the new V6 unit and its predecessor is a reduction in the V-angle between the cylinder banks from 90 degrees to 60 degrees. This enabled the balancer shaft countering primary vibrations to be omitted, and as a result the driver registers an outstanding level of comfort.
A completely new intake and exhaust gas system with a variable-resonance intake manifold and optimized airflows was also developed for the new V6. This enabled the output of the 3499 cc engine to be increased to 225 kW (306 hp) (Previous engine of the same displacement in the S-Class: 200 kW/272 hp). Torque has increased from 350 N·m to 370 N·m, and is available between 3500 and 5250 rpm.
The S 350 with the new V6 engine consumes 7.6 liters per 100 kilometers (31 mpg US) (CO2 emissions: 177 g/km), which makes it 24% more economical than its predecessor (10.0 L/100 km, 23.5 mpg US). It also makes the new V6 the benchmark in its segment for a comparable output (provisional figures)."
"New V-Engine Generation from Mercedes-Benz Feature 3rd Generation Gasoline Direct Injection and New Operating Modes for More Power and Torque and Lower Fuel Consumption
Mercedes-Benz is introducing its newly developed V-series (V6 and V8) engines. The new V engines offer more power and torque, and 22-24% lower fuel consumption than their predecessors.
Mercedes-Benz has achieved this increase in efficiency through the use of a technology package that incorporates third-generation direct gasoline injection with spray-guided combustion, multiple injection and multi-spark ignition; new operating modes; the use of a new start/stop function as standard; and other features.
Both the new V6 and the new V8 from Mercedes-Benz have aluminium crankcases, pistons and cylinder heads. The crankshaft, connecting rods and valves are of special forged steel. The technology package in the new engine generation includes a number of new developments:
In combination with multi-spark ignition, a further developed, third-generation gasoline direct injection system with spray-guided combustion and piezo-electric injectors offers further possibilities for fuel savings—in the V8 by means of an improved, homogeneous combustion process, and in the V6 by a new, stratified combustion process with a considerably extended characteristic map and fuel-efficient lean-burn technology.
In conjunction with start/stop technology, shift point adjustment and specific friction-reducing measures, improvements in day-to-day fuel consumption by more than 20% are possible.
Power consumption by ancillary units has been reduced. These include an optimized water pump with 2nd-generation thermal management, a demand-controlled oil pump, a volume-controlled high-pressure fuel pump and an intelligent generator management system.
Lightweight construction techniques and detailed improvements have also reduced in-engine friction considerably compared to the previous engine.
Direct injection system. The system pressure is up to 200 bar, the pressure being variably optimized according to the engine’s characteristic map. Completely newly developed piezo-electric injectors allow up to five injections per intake stroke for optimal mixture formation.
The piezo-electric injector has a response time of 0.1 milliseconds, allowing the fuel injection to be very sensitively and precisely adjusted to the current load and engine speed, with a beneficial effect on emissions, fuel consumption and combustion noise.
The multiple injections even in tiny quantities made possible with piezo-electric injection technology were used by Mercedes-Benz engineers to control a wider characteristic map with the efficient lean-burn process, and to provide the conditions for further functions.
New operating modes. As the first new operating mode, Mercedes-Benz engineers have developed “Homogeneous stratified combustion” (HOS). HOS is a combination of homogeneous lean-burn and classic stratified combustion. The first injection is sprayed into the intake stroke, forming a homogeneous basic mixture. Actual stratified injection takes place during the compression stroke before ignition, and is a single or double injection depending on the characteristic map.
Another new operating mode is known as “Homogeneous Split” (HSP). In this homogeneous combustion process, more than 95% of the fuel is singly or multiply injected, followed a very small ignition injection to stabilize combustion. This is used when combustion conditions are difficult.
The characteristic map of the new Mercedes-Benz V6 engine is therefore basically divided into up to four areas:
idling range (homogeneous)
low partial load up to 4 bar and 3800 rpm (stratified)
medium partial load 4 to 8 bar and up to 4000 rpm (HOS)
high load and entire engine speed range (homogeneous or HSP)
The V8 engine is operated homogeneously over the entire characteristic map, but under high load homogeneous or HSP operation is used to improve smooth running characteristics.
Multi-spark ignition. The third-generation direct injection system also features rapid multi-spark ignition (MSI). Following the first spark discharge and a brief combustion period, the coil is rapidly recharged and a further spark is discharged. The MSI system enables up to four sparks to be discharged in rapid succession within one millisecond, creating a plasma with a larger spatial expansion than conventional ignition.
Controlling this rapid multi-spark ignition enables both the time lapse before the next spark and the combustion duration for the relevant operating point to be optimally adjusted. This provides scope for optimizing the centre of combustion and improving residual gas compatibility, especially during stratified charge operation. Fuel consumption can be reduced by roughly 2% in this way.
Fuel savings of up to 4% are possible alone by the use of piezo-electric injection technology in combination with multi-spark ignition, depending on the driving cycle.
Cylinder head with new camshaft adjuster. On the basis of the previous engine’s architecture, Mercedes-Benz engineers developed the variable, hydraulic vane-type camshaft adjusters for the intake and exhaust sides. These now have a larger adjustment range of 40 degrees with reference to the crankshaft.
They were also able to improve the functionality, achieving a 35% greater adjustment speed and adjustability at an oil pressure as low as 0.44 bar. Despite the better performance, this new development features significantly smaller dimensions and low weight. For this reason the installation space on the longitudinal and vertical axes of the engine was able to be reduced by around 15 millimeters.
Two-stage chain drive for low noise. The extreme compactness of the camshaft adjusters was achieved by the new, two-stage chain drive. This drives short secondary chains—one per cylinder bank—via a primary chain and an intermediate gear. All three chains can be individually adjusted via a chain tensioner. This results in low tensioning forces and low chain dynamics, ensuring consistent timing and outstanding acoustic properties, with friction reduced even further. The new chain drive is compact and ensures low-noise operation.
Controlled oil pump with two pressure stages. A fourth chain drives a likewise completely newly developed, variable vane-type oil pump. The operates with two pressure stages, depending on the characteristic map. At low engine speeds and loads the pump runs at a low pressure of two bar. At this time the oil-spray nozzles for piston cooling are switched off. The high-pressure stage is activated at the upper load and engine speed levels. With this control concept, the lubrication and cooling points of the engine can be supplied with significantly lower drive energy than would be possible with an uncontrolled pump.
New coolant ducting and 3-phase thermal management. The coolant ducting in the cylinder head is also completely new. The water mantle is of two-piece construction to improve flow. This leads to specific increases in flow speeds and heat dissipation at certain points, accompanied by a reduction in pressure throughout the coolant circuit. This has made it possible to reduce the power output of the water pump despite an increased engine output.
As it warms up, the flow of coolant is regulated by a 3-phase thermal management system so that it rapidly reaches normal operating temperature. Initially the coolant remains at rest in the engine. It then circulates in the engine circuit, but without the radiator. When a temperature of 105 °C has been reached in normal operation (87 °C under high load), the vehicle’s radiator is included in the circuit. The water supply to the interior heating system is separately controllable.
Component weights have also been reduced by the concerted replacement of aluminium and steel by plastics, e.g. for the thermostat, belt pulley, wheel, heater valve and hydraulic lines.
Start/stop function with direct-start. The new start/stop system operates with starter-supported direct-start. This means that when the engine is switched off, the attitude of the crankshaft is registered by a new crankshaft sensor so that the engine control unit knows the positions of the individual pistons. On restarting, it can then select the cylinder that has the most suitable piston position for first ignition. After the starter has briefly turned over the engine, reliable injection, ignition and combustion is immediately possible.
Minimized friction. Particular attention was paid to reduced friction in both engines. This was primarily achieved by a reduction in flow through the oil and water pumps, low-friction pistons, piston rings and cylinder walls, plus the new thermal management system and chain drive.
Modularization. The new Mercedes-Benz engine family is based on modularization. It allows the use of a stop-start function, 4MATIC all-wheel drive and combination with a hybrid module. The new Mercedes-Benz V-engine generation will initially be used as an 8-cylinder in the CL-Class, and later in the S-Class from autumn 2010.
V8. On the basis of its predecessor, the new V8 has undergone significant further development. It has a 15-percent smaller displacement (4663 cc rather than 5461 cc) but generates 320 kW (435 hp) and therefore around 12 percent more output than the preceding unit (285 kW/388 hp). Whereas the current CL 500 consumes 12.3 liters per 100 kilometers (19 mpg US), this figure drops to 9.5 liters (25 mpg US) with the new engine—a reduction of 22%.
CO2 emissions have likewise fallen by 22%, from 288 g/km to 224 g/km. At the same time torque has been raised from 530 N·m to 700 N·m (32%). The high maximum torque is already available from 1800 rpm.
In the new V8, Mercedes-Benz engineers primarily achieved a high output for a lower displacement by using two turbochargers—one for each bank of cylinders. The intake air is forced into the eight combustion chambers at an overpressure of up to 0.9 bar, with the turbine blades rotating at up to 150,000 rpm. The turbochargers and their hot gas ducting are accommodated on the outsides of the cylinder heads. This enabled the intercooler module with its air/water intercooler and charge-air distributor to be located inside the V of the engine.
The chargers were configured to provide high torque even at low engine speeds—compared to the previous engine the result is an increase of more than 40% at 2000 rpm. 600 N·m is available between 1600 and 4750 rpm.
The engine is based on a further development of the previous engine’s die cast aluminium crankcase with cast-in aluminium/silicon (Silitec) cylinder liners. Basic and connecting rod journal diameters were adopted from the preceding engine, while for load reasons the piston compression height was raised by just under four millimeters. By reducing the lift and shortening the connecting rod by 2 millimeters, it was possible to retain the interior height of the crankcase.
V6. The new V6 engine is naturally aspirated, and has the potential for future use of a turbocharger due to the modular design concept. The most striking change between the new V6 unit and its predecessor is a reduction in the V-angle between the cylinder banks from 90 degrees to 60 degrees. This enabled the balancer shaft countering primary vibrations to be omitted, and as a result the driver registers an outstanding level of comfort.
A completely new intake and exhaust gas system with a variable-resonance intake manifold and optimized airflows was also developed for the new V6. This enabled the output of the 3499 cc engine to be increased to 225 kW (306 hp) (Previous engine of the same displacement in the S-Class: 200 kW/272 hp). Torque has increased from 350 N·m to 370 N·m, and is available between 3500 and 5250 rpm.
The S 350 with the new V6 engine consumes 7.6 liters per 100 kilometers (31 mpg US) (CO2 emissions: 177 g/km), which makes it 24% more economical than its predecessor (10.0 L/100 km, 23.5 mpg US). It also makes the new V6 the benchmark in its segment for a comparable output (provisional figures)."
07-14-2010, 10:19 AM
#10
Le Mans Master
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You right most of those things can be implemented in an OHV engine. The only one I question is the variable valve timing. It is implemented differently with different affect on a single cam in-block engine. A 40 degree range is quite a lot. I fully expect an increase in both power and fuel efficiency on the order of 15%-20% Which would allow GM to reduce the displacement and maintain the HP. This would give them room to raise HP as necessary later in the life cycle by just adjusting displacement.
There is a lot of life left in the gasoline internal combustion engine.
I see people talking about stratified charge technology like it is new. Didn't Hodna do that in the 70's?
There is a lot of life left in the gasoline internal combustion engine.
I see people talking about stratified charge technology like it is new. Didn't Hodna do that in the 70's?
07-14-2010, 05:58 PM
#11
All that Mercedes did is make an engine that is way too complicated for the gains realized. It will make the used cars drop more in value because of imposibley expensive repair costs. That is what is so great about the gm smallblocks and ls engines is the continuity and interchangability of parts. The electronics world makes its products overly complicated...windows software anyone?
