7DCT450

1. Precise Hydraulic Control of Dual Clutches, Enhanced DCT Shifting Response Speed

Targeting the characteristic of "alternating operation of dual clutches and power-interruption-free shifting" of the 7DCT450 transmission, it adopts a combined design of 14 sets of high-precision proportional solenoid valves (PWM control frequency: 200Hz) and two-stage pressure regulating valves. It can real-time capture dynamic parameters such as engine torque, vehicle speed, throttle opening, and driving mode (ECO/SPORT/INDIVIDUAL), and independently adjust the engagement pressure of K1 (odd gears/reverse gear) and K2 (even gears) clutches with an accuracy of ±0.06MPa.

Compared with ordinary DCT valve bodies, the shifting response speed is increased by 35%, and it can complete gear shifting (e.g., 3rd gear → 4th gear) within 50-150 milliseconds, completely eliminating the "jitter" during low-speed (15-30km/h) shifting of dual clutches. Meanwhile, through the optimization of "pre-shifting logic"—pre-charging oil pressure for the next gear while the current gear is working (e.g., pre-establishing 12-15MPa pressure for the 3rd gear clutch when driving in 2nd gear), "gap-free" power transmission is achieved. Whether it is frequent start-stops in urban congested road conditions or gear shifting from 6th to 7th gear during high-speed cruising (120km/h), it can maintain a "lightning-fast shifting + smooth and shock-free" driving experience, meeting the dual needs of sports models for power response and comfort.

2. Weather-Resistant Materials and Precision Craftsmanship, Extended DCT Service Life

The core valve plate is made of high-strength ADC12 die-cast aluminum alloy, undergoing T6 heat treatment (solution temperature: 530℃, aging temperature: 160℃) and surface hard anodizing process (oxide layer thickness: 12-16μm). Its hardness is increased to over HV780, enabling it to withstand high-frequency oil pressure impacts during DCT transmission operation (maximum pressure resistance: 32MPa), effectively resisting valve body deformation and oil passage wear under long-term high load (main oil passage wear is controlled within 0.008mm per 100,000 kilometers).

The internal spool uses a SUS440C stainless steel substrate with a Diamond-Like Carbon (DLC) coating, reducing the friction coefficient by 42% and minimizing the risk of spool jamming at low temperatures (-30℃) (the increase in operating resistance is no more than 12%). The sealing components are made of hydrogenated nitrile butadiene rubber (HNBR) specified by VW, which is oil-resistant, high-temperature-resistant, and low-temperature-resistant (-40℃~150℃), with a compression set rate of less than 7%. This prevents leakage of dual-clutch special oil (such as VW DQ 350) and avoids severe wear of dual clutches and planetary gear sets due to oil shortage (e.g., clutch plate ablation, input shaft bearing jamming). According to third-party testing, the service life of this valve body is 55% longer than that of ordinary similar products, making it suitable for long-term high-load use of the 7DCT450 transmission (e.g., sports driving, frequent rapid acceleration).