6T45

1. Precise 6-Speed Gear Control for Smooth and Efficient Shifting

The 6T40/6T45 TCU adopts a GM-specific 6-speed AT synergy algorithm, tailored to the mechanical characteristics of the 6T40 (lower torque capacity, for 1.5L-1.8L engines) and 6T45 (higher torque capacity, for 2.0L-2.4L engines) gearboxes. It enables millisecond-level synchronization of gear shifting actions, balancing daily driving comfort and fuel economy. The TCU collects real-time signals from 11+ dedicated sensors (vehicle speed, engine torque, throttle position, transmission oil temperature, clutch pressure, etc.) and, via a built-in GM-customized 32-bit MCU (processing frequency up to 150 MHz), calculates the optimal shifting timing and clutch pressure curve in 9-13 ms.

For 6T40-equipped models (e.g., Chevrolet Cruze 1.5L), during urban commuting (throttle opening 30%-50%), the TCU activates the "economy-focused shifting strategy": it advances upshifting (e.g., shifting from 3rd to 4th gear at 40 km/h instead of 36 km/h) and controls the clutch engagement pressure gradient to 0.12 MPa/10 ms, reducing fuel consumption by 6%-9% compared to aggressive shifting logic. In emergency acceleration scenarios (throttle opening > 85%), the TCU triggers a "rapid downshift" (e.g., from 5th gear directly to 3rd gear) and increases the solenoid valve pressure by 0.35 MPa in 11 ms, shortening the shift time to 0.28-0.35 seconds—meeting the basic dynamic needs of daily driving. For 6T45-equipped models (e.g., Buick Regal 2.0L), the TCU optimizes high-torque transmission control: when the engine outputs peak torque (230-250 N·m), it maintains the clutch pressure at 1.8-2.1 MPa to avoid slipping, ensuring stable power delivery during high-load driving (such as climbing slopes or overtaking).

2. Adaptive Adjustment for Diverse Working Conditions

A key functional advantage of the 6T40/6T45 TCU lies in its working condition-adaptive control capability, which optimizes transmission performance based on factors such as driving environment, load, and temperature—addressing the diverse usage scenarios of GM’s mid-to-low-end models (urban stop-and-go, highway cruising, low-temperature cold starts). It adopts a "multi-parameter fusion" control logic: the TCU adjusts the shifting map and clutch pressure in real time based on comprehensive data including oil temperature, engine load, battery voltage, and driving mode (Eco/Comfort).

During highway cruising (e.g., 100 km/h constant speed in 6th gear), the TCU reduces the clutch pressure to 0.9-1.1 MPa, minimizing friction loss between clutch plates and lowering fuel consumption by approximately 7% compared to fixed-pressure control—ideal for long-distance driving needs. In urban stop-and-go traffic (average speed < 25 km/h), it extends the clutch engagement time by 0.15 seconds and reduces the pressure gradient to 0.09 MPa/10 ms, reducing shifting jitter (amplitude < 3.2 m/s²) and improving passenger comfort. For low-temperature cold starts (< -20℃), the TCU activates the "oil pre-warming mode": it controls the transmission oil pump to circulate oil at a low speed and maintains a clutch pressure of 0.6-0.8 MPa for 45 seconds until the oil temperature rises to 10℃, solving the problem of difficult shifting in cold weather. Under high-temperature conditions (oil temperature > 110℃), it increases the oil circulation rate and reduces the clutch pressure by 0.2 MPa, preventing transmission overheating and ensuring stable operation.