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Brand: C.OEFT
OE numbers:28250-RDK-014
EAProduct Name: Transmission Valve
Compatible model:28250-RJB-004
Product status: New
Product weight:1.034KG
Packaging size: 28X17X15 cm
Product packaging:Neutral Package
Car Series:Japanese
Car Type: for Honda Acura
1. Multi-Gear Precise Oil Circuit Control for Dynamic Shifting
The 28250-RDK-014 solenoid valve adopts a high-response multi-gear oil circuit design (covering 3rd-9th gears for 9-speed AT and main drive/secondary drive pulley control for high-performance CVT) to achieve rapid and smooth gear shifting. When the TCU detects a gear-shifting demand (e.g., 6th-7th gear shift in 9-speed AT during high-speed overtaking), it sends a high-frequency pulsed electrical signal to the solenoid valve’s coil. The coil generates a high-intensity and rapidly adjustable magnetic field, driving the spool to move axially in a micro-stepped manner—this not only opens the oil passage to the 7th gear clutch with millisecond-level precision but also synchronously adjusts the oil discharge speed of the 6th gear clutch through an electronic throttle valve, ensuring the 6th gear clutch disengages at a linear rate while the 7th gear clutch engages dynamically without power interruption.
For example, in a Honda CR-V (6th generation) equipped with the 9-speed AT (9AT transmission, compatible with the 28250-RDK-014 solenoid valve), when accelerating from 90 km/h to 120 km/h during overtaking, the TCU coordinates this solenoid valve to complete the 6th-7th gear shift. The entire process takes merely 0.22 seconds, with a jerking amplitude of less than 4.5 m/s²—far below the industry average of 6.5 m/s² for mid-size SUV 9-speed AT models. When de-energized, the high-elasticity titanium alloy return spring (stiffness 15.5 N/mm) resets the spool in 10 ms, promptly closing the target oil circuit to prevent residual pressure from causing clutch drag, thus ensuring stable transmission operation during frequent dynamic driving.
2. Adaptive Pressure Regulation for Complex Working Conditions
A prominent functional advantage of the 28250-RDK-014 solenoid valve is its intelligent adaptive pressure regulation capability, which can balance shifting dynamics, torque transmission efficiency, and fuel economy under diverse complex working conditions (high-speed overtaking, urban stop-and-go, off-road climbing, high-temperature driving). It adopts a closed-loop control mode with triple sensors (pressure sensor + oil temperature sensor + torque sensor): the TCU adjusts the coil current duty cycle (0%-100%) in real time based on comprehensive parameters such as vehicle speed, engine torque, oil temperature, and driving mode (Eco/Sport), controlling the clutch/brake oil chamber pressure with an accuracy of ±0.05 MPa—meeting the performance requirements of Honda’s dynamic models while optimizing energy consumption.
During high-speed light-load cruising (e.g., 110 km/h constant speed in 9th gear), the solenoid valve reduces the clutch pressure to 0.7-0.9 MPa, minimizing friction loss between clutch plates and reducing fuel consumption by approximately 8% compared to fixed-pressure control—addressing the fuel economy needs of mid-size SUV users for long-distance driving. Under heavy-load off-road conditions (e.g., climbing a 25° slope at 40 km/h), it increases the pressure to 2.2-2.5 MPa, ensuring the clutch engages tightly to avoid slipping and torque loss—a common concern in SUV models with higher weight and off-road demands. For high-temperature driving (ambient temperature above 35℃), the solenoid valve adjusts the pressure to 1.1-1.3 MPa, reducing clutch friction heat generation by 15% and preventing transmission overheating. In low-temperature cold starts (below -22℃), it activates the "rapid pre-warm mode": the built-in oil temperature sensor monitors the oil temperature in real time, maintaining a pressure of 0.55-0.75 MPa for 38 seconds until the oil temperature rises to 12℃, then gradually increasing the pressure to the normal range—solving the problem of difficult shifting in cold weather for Honda’s high-performance transmissions.
1. Broad Compatibility with Honda Mainstream Models
The 28250-RDK-014 solenoid valve is a dedicated component for Honda’s mainstream 9-speed AT and high-performance CVT transmission systems, widely used in global and domestic Honda models:
Global Model Adaptation: Fully compatible with Honda models equipped with 9-speed AT (9AT) and high-performance CVT (CVT with Earth Dreams Technology), including the Honda Accord (10th generation), CR-V (6th generation), Pilot (3rd generation), and Passport (2nd generation). Its electrical parameters (coil resistance: 11.2±0.2 Ω, operating voltage: 12V DC) and structural dimensions (installation hole spacing: 24.5±0.06 mm) perfectly match the original transmission valve body. The connector adopts a waterproof and anti-interference design (IP6K9K protection level) to meet the electrical stability requirements of complex transmission systems. No modification is needed during replacement, ensuring consistent performance with the original factory solenoid valve.
Domestic Joint-Venture Adaptation: In China, it is a standard component for GAC Honda’s Accord, CR-V, and 东风本田 (Dongfeng Honda)’s UR-V, Avancier. These joint-venture models adhere to Honda’s global quality standards for mainstream models, and the 28250-RDK-014 solenoid valve has passed rigorous validation tests: a 10,000-hour high-temperature durability test (145℃), a 13,000-cycle pressure impact test (0.1-3.0 MPa), a -40℃ to 145℃ extreme temperature cycle test, and a 5,000-hour high-humidity test (95% relative humidity)—ensuring reliable operation in diverse climate conditions across China, from the cold northeast to the hot and humid south, and even in coastal areas with high salt spray.
Dual Transmission Type Adaptation: It can seamlessly adapt to both 9-speed AT and high-performance CVT systems. For 9-speed AT models (e.g., CR-V 9AT), the solenoid valve’s pressure regulation curve is optimized for multi-gear rapid shifting, with a maximum pressure of 2.5 MPa; for high-performance CVT models (e.g., Accord 2.0T CVT), the maximum pressure is calibrated to 2.3 MPa to match the continuous torque output of the CVT. This dual-adaptation capability eliminates the need for developing separate solenoid valve models, reducing inventory pressure for Honda repair shops.
2. High-Durability Materials and Precision Manufacturing
Premium Material Selection: The valve body of the 28250-RDK-014 solenoid valve is crafted from high-strength aluminum alloy (6061-T6) through precision forging and CNC machining. This material boasts a tensile strength of 310 MPa and excellent corrosion resistance, capable of withstanding long-term immersion in Honda’s dedicated ATF (Dexron VI) and CVT fluid (Honda CVT Fluid) without deformation or corrosion. The surface is treated with a triple-layer anti-corrosion coating (chromate passivation + nickel plating + PTFE coating), ensuring no rust even after 450,000 kilometers of use. The spool is made of high-hardness alloy steel (42CrMo) and undergoes a five-step precision grinding process, with a surface roughness of Ra 0.015 μm—reducing friction with the valve body by 30% compared to ordinary stainless steel spools. The sealing ring adopts perfluoroether rubber (FFKM), which maintains excellent sealing performance at -40℃ to 260℃ and exhibits strong resistance to ATF/CVT fluid aging, effectively preventing oil leakage caused by seal failure.
Precision Manufacturing Process: The product adheres to Honda’s "Zero Defect" manufacturing philosophy. Key dimensions (such as spool diameter and oil passage diameter) are controlled by high-precision CNC machining centers with an accuracy of ±0.001 mm. The coil is wound with 0.19 mm high-purity oxygen-free copper wire (purity 99.99%) using a computer-controlled winding machine with tension control, ensuring uniform winding density and stable electrical performance—even in the high-electromagnetic-interference environment of Honda’s Earth Dreams engine systems. After assembly, each solenoid valve undergoes a 100% pressure test (0.1-3.0 MPa), a leakage test (leakage rate ≤0.1 mL/min), a response speed test (≤15 ms), and a high-temperature performance test (145℃ for 2 hours), with a pass rate of 100%—far exceeding the industry average pass rate of 97%.
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