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Brand: C.OEFT
OE numbers: 722.9
Product Name: Transmission Valve
Compatible model:
Product status: Remanufactured
Product weight: 1.140KG
Packaging size: 28X17X15cm
Product packaging: Neutral Packaging
Car Series: American
Car Type: for Mercedes-Benz
1. Torque Converter Clutch (TCC) Control: Balancing Efficiency and Comfort
The 722.9 transmission solenoid valve plays a key role in controlling the 7G-Tronic transmission's torque converter clutch, a critical component for improving fuel economy and driving comfort:
Smooth TCC Engagement for Highway Efficiency: At speeds above 70km/h (a common highway cruising speed), the TCU sends a PWM signal to the solenoid valve, which gradually increases the TCC oil pressure. The solenoid valve adjusts the pressure in 0.01bar increments, ensuring that the TCC engages without "judder"—a common issue with low-precision solenoid valves. Once fully engaged, the TCC eliminates slip between the torque converter's pump wheel and turbine wheel, increasing transmission efficiency by 10-15% and reducing fuel consumption.
Intelligent TCC Disengagement for Low-Speed Comfort: During low-speed driving (below 35km/h) or when the driver releases the accelerator (coasting), the solenoid valve quickly reduces the TCC oil pressure to disconnect the clutch. This prevents engine stalling and ensures smooth power delivery when the driver reapplies the accelerator. In Mercedes-Benz's "ECO Start/Stop" mode, the solenoid valve also coordinates with the TCU to disengage the TCC before the engine shuts off, ensuring quick and smooth restarts.
2. Shift Solenoid Control: Enabling 7-Speed Precision Shifts
As the core execution component for the 722.9 transmission's 7-speed shifts, the solenoid valve works with the TCU to control the engagement and disengagement of the transmission's clutches and brakes, ensuring precise and rapid gear changes:
During upshifts (e.g., 2nd to 3rd, 5th to 6th) or downshifts (e.g., 6th to 4th during overtaking), the solenoid valve adjusts the oil pressure of the target clutch/brake based on real-time data from the engine's torque sensor and the vehicle's speed sensor. For example, during a full-throttle downshift from 7th to 4th gear (a common maneuver for overtaking on the highway), the solenoid valve increases the brake oil pressure to 11-13bar in 0.04 seconds, completing the shift in just 0.3 seconds—faster than the industry average of 0.5 seconds for 7-speed transmissions.
Adaptive Shift Compensation for Wear: As the vehicle accumulates mileage (over 150,000 kilometers), the transmission's clutch plates may experience normal wear. The solenoid valve can compensate for this wear by increasing the oil pressure by 0.7-1.2bar based on TCU feedback of shift time. This restores the original shift feel, avoiding issues such as "soft shifts" (slow engagement) or "harsh shifts" (abrupt engagement) caused by wear—ensuring that the transmission maintains like-new performance even in older vehicles.
1. Factory-Level Precision Matching for 7G-Tronic Transmission System
The 722.9 transmission solenoid valve is developed based on the unique hydraulic control logic and TCU (Transmission Control Unit) communication protocol of the 722.9 transmission, achieving 100% factory-level compatibility with the original transmission system. Unlike universal aftermarket solenoid valves, it is calibrated for the 722.9 transmission's 7-gear ratio design (with a first gear ratio of 4.387 and a seventh gear ratio of 0.734) and the high-torque output characteristics of matching Mercedes-Benz engines (such as the M272 V6 and M273 V8 engines). During high-load scenarios such as full-throttle acceleration or uphill driving, it can respond to the TCU's pressure adjustment commands within 0.06 seconds, avoiding the "shift hesitation" and "gear hunting" issues common in non-original components. Additionally, its interface dimensions (including an oil port diameter of 6.0mm and a mounting hole spacing of 27mm) are millimetrically consistent with the 722.9 transmission's valve body, eliminating the need for secondary modification and ensuring seamless integration with the original hydraulic system—critical for maintaining the transmission's factory-set performance standards.
2. Premium Material Selection for Extreme Durability
Adhering to Mercedes-Benz's strict quality standards, the 722.9 transmission solenoid valve uses high-grade materials and advanced manufacturing processes to ensure long-term reliability under harsh working conditions:
High-Temperature Resistant Core Components: The electromagnetic coil uses Class 200 high-temperature resistant enameled wire (capable of withstanding continuous operation at 200℃) and a nickel-plated copper core, which can maintain stable magnetic performance even when the transmission oil temperature reaches 160℃ (a common scenario in high-speed long-distance driving). The valve body is made of forged aluminum alloy (A356-T6), which has both high strength (tensile strength of 310MPa) and excellent heat dissipation, preventing deformation caused by temperature fluctuations.
Wear-Resistant Valve Core with Nano-Coating: The valve core is crafted from SUJ2 bearing steel and coated with a 5μm-thick diamond-like carbon (DLC) layer. This coating reduces friction coefficient by 40% compared to traditional chrome plating, allowing the valve core to withstand over 2.5 million cycles of reciprocating motion without significant wear (the industry average for luxury car solenoid valves is 2 million cycles). The DLC layer also has strong corrosion resistance, effectively resisting chemical erosion from long-term use of Mercedes-Benz-specific ATF (Automatic Transmission Fluid) such as MB 236.14.
: The oil seal and electrical connector seal use fluoroelastomer (FKM) material, which can maintain elasticity and sealing performance for more than 8 years in the presence of transmission oil and high temperatures. The electrical connector adopts a gold-plated pin design, reducing contact resistance by 30% and avoiding poor contact caused by oxidation—an issue that often leads to "intermittent shift faults" in older vehicles.
3. High-Precision Hydraulic Control for Superior Driving Comfort
The 722.9 transmission solenoid valve is designed to achieve ultra-precise hydraulic pressure regulation, a key factor in the 7G-Tronic transmission's legendary shifting smoothness:
PWM Signal Resolution with Micro-Level Adjustment: It supports a PWM (Pulse Width Modulation) signal with a frequency of 1000Hz and a duty cycle adjustment range of 3%-97%. This allows the solenoid valve to adjust the hydraulic pressure in increments of 0.01bar, ensuring that the transmission's clutches and brakes engage/disengage at a rate that matches the engine's torque output. For example, during the 3rd-to-4th gear shift (a common transition in urban driving), the pressure adjustment error is less than ±0.05bar, completely eliminating shift shock and creating a "seamless" shifting experience.
Adaptive Pressure Compensation for Dynamic Scenarios: When the vehicle is accelerating or decelerating rapidly, the solenoid valve can dynamically adjust the pressure based on real-time data from the engine's torque sensor and the transmission's speed sensor. For instance, during sudden acceleration (throttle opening >90%), it increases the clutch pressure by 1.2-1.5bar in 0.03 seconds to prevent clutch slip; during sudden braking, it reduces the pressure by 0.8-1.0bar to avoid engine stalling—balancing performance and comfort in extreme driving scenarios.
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