The 9g Tronic gearbox is the primary 9-speed automated transmission full with torque converter, however now, this method, which is designed for premium automobiles, is ready to debut within the E 350 BlueTEC.
A traditional automated transmission’s drive factor is a hydrodynamic torque converter. Within the 9g Tronic transmission, the hydraulic circuit discovered within the torque converter has been improved, and the effectivity has additionally been raised to 92%. That is essential for gas economic system as a result of there’s a have to maintain the losses caused by physics when engine torque is being transferred to the enter shaft transmission to a naked minimal. Put in another way, the 9g-Tronic transmission a major quantity of engine energy into tractive drive. The primary-generation 7g Tronic had 85% effectivity.
Key options of 9G Tronic Transmission
Twin turbine torsion damper and centrifugal pendulum
The torsion damper is just not solely one of many primary options that improve consolation however can also be an necessary fuel-saving factor in automated transmission. It makes up for vibrations and eccentricities inside the transmission. The legislation of physics states that the decrease the highway pace and rpm, and the decrease the cylinder numbers, the extra pronounced they are often. The result’s that there’s a battle between fuel-efficient operation and luxury. However that is simply resolved by utilizing a twin-turbine damper full with a centrifugal pendulum. This may shift the middle of gravity, relying on the car’s rpm.
Moreover, the improved damping permits the discount of slip within the torque converter clutch, which makes it extra fuel-efficient.
The engineers have additionally built-in a return spring into the 9g Tronic torque converter clutch. Beforehand, the multi-disc lockup clutch was managed solely hydraulically. The return strain spring permits activation even when the rpm may be very low.
Oil provide utilizing two pumps
The 9g Tronic comprises two pumps to allow the environment friendly provide of 2nd-generation artificial oil. The principle pump, which is put in off-axis, is situated adjoining to the principle shaft. It’s additionally pushed by way of a sequence.
In an automated transmission, for instance, the 7g Tronic, the principal oil pump used to ring the transmission shaft, and it was immediately pushed. This manner, the transmission shaft diameter made it almost not possible to scale back the scale of the pump to the suitable dimension. This has prompted the vane cell pump to be now put alongside the first shaft. Additionally, its dimension is lowered to match necessities.
The mechanical principal pump, whose work is supplying oil to the electrohydraulically run automated transmission system when the inner combustion engine is on, is supported by one other electrical secondary pump. The benefit of this design is that it permits the lubrication and coolant movement to be actively managed on demand. It additionally implies that the 9g Tronic design may also be helpful to a begin/cease system.
While you swap off the engine, it results in the actuation of the electrical secondary pump, which not solely ensures an outlined primary construction but additionally ensures that each one the important capabilities are maintained. When it’s time for the driving force to re-start the engine, the supply of oil by the auxiliary pump ensures clean acceleration. In some working states with the engine on, the secondary pump additionally helps the first pump. This may occur at very excessive temperatures or extraordinarily low engine speeds. In such a case, oil movement is elevated accordingly to make sure that the gears shift easily.
Shorter processing instances and improved high quality
A 9g Tronic transmission is characterised by shorter processing instances per shaft and on the identical time, the manufacturing high quality is considerably improved. To chop down cycle instances through the manufacturing course of, engineers removed the traditional information sleeves when performing spot drilling. The machines make deep holes freehand whereas guaranteeing dimensional accuracy. Moreover, excessive working speeds are allowed by single-fluted cemented carbide drills that assure excessive working speeds.
In 7g Tronic plus automated transmission, the pace was about 125 millimeters per second. This adjustments to a drilling pace of about 250 millimeters per minute. The quick impact of that is that solely three minutes are wanted for the principle shaft to be processed. That is about 63% much less time in comparison with 7g Tronic plus manufacturing. Due to the enhancements above, Mercedes-Benz engineers are implementing a venture referred to as “Inexperienced Undertaking”.
Compact light-weight building
The change of technology from 7g Tronic to 9g Tronic additionally noticed improvement engineers focus extra on the compact light-weight design space. Regardless of having two additional gears and the best transferrable torque that simply exceeds 1000 nm, the set up house required by the brand new automated transmission is similar. Additionally, it’s lighter by one Kilogram.
The 9g Tronic design additionally retains the two-piece housing design. Because of this the housing of the torque converter is made utilizing light-weight aluminum alloy. Alternatively, the transmission housing makes use of a plastic oil pan that’s weight-optimized.
New drilling course of
Making a shaft like it is a big problem for manufacturing engineers. It has very particular necessities, particularly when doing the three deep holes. For instance, the drilled holes measuring 36.15 mm should adhere to the necessities of a thousandth millimeter. Moreover, machining should observe precisely outlined geometrical specs:
- Parallelism and distance of the holes viz-a-vis one another.
- The holes’ distance and parallelism versus the exterior haft floor,
- The necessity to keep away from twisting fully throughout drilling
- The person holes should have the right depth
- The three drilled holes should have radial positioning to make sure free movement to transverse holes.
- The drilling have to be freed from any residues and particularly microfine swarf shouldn’t be left within the holes.
The 9g Tronic gearbox actually is a masterpiece. It has a number of parts and options heaps extra new manufacturing processes which suggests elevated complexity. The automated gearbox is destined to carry out effectively out there in comparison with its predecessor, the 7g Tronic plus. It additionally has a number of benefits like lowered processing instances, improved high quality, and sturdier and light-weight building.