Hydraulic Pump Torque Control for Drivetrain Gear Shifts
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Solution Overview
Problem
Conventional drivetrain systems experience reduced engine torque and turbo pressure during gear changes, leading to decreased vehicle speed and potential missed gear selection in critical situations, and existing power shift transmissions are costly and complex.
Innovation Solution
A method controlling a drivetrain with a hydraulic transmission system, where the hydraulic pump is directly driven by the combustion engine to maintain engine torque and turbo pressure during gear changes by increasing load torque from the pump, ensuring a smooth transition and maintaining traction without energy-consuming torque converters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a conventional transmission with main clutch is used during gear change, then the structure is simpler and cost is lower, but the engine torque and turbo pressure decrease leading to slower response and potential missed gear selection
Solution Approach 1:
The patent combines a conventional transmission system with a hydraulic transmission system to create a dual-path power delivery system. During gear changes, the hydraulic system maintains torque delivery while the conventional transmission shifts, eliminating the torque interruption problem of pure conventional systems without requiring a full complex power shift transmission.
Solution Approach 2:
The hydraulic transmission system serves multiple functions: it acts as a torque maintenance mechanism during gear changes, provides an alternative power delivery path, and enables smooth torque transitions. This multi-functionality allows the system to maintain simplicity while solving the torque buildup time issue.
2Loss of time
If a power shift transmission is used to maintain engine speed and turbo pressure during gear change, then the torque buildup time is reduced, but the device complexity and manufacturing cost increase
Solution Approach 1:
The patent segments the transmission system into two independent parts: a conventional transmission for gear changes and a hydraulic transmission for torque maintenance. This segmentation allows each subsystem to be optimized independently, achieving fast torque response without requiring the entire transmission system to be complex.
Solution Approach 2:
The hydraulic transmission system acts as an intermediary between the engine and the wheels during gear changes. It mediates the torque delivery by providing an alternative path that maintains torque while the conventional transmission shifts, avoiding the need for a fully complex power shift system.
3Ease of operation
If the main clutch is opened during gear change in conventional transmission, then the gear shift can be executed, but the engine torque transmission is interrupted and vehicle speed decreases
Solution Approach 1:
The hydraulic transmission system ensures continuous torque delivery to the wheels during gear changes. While the conventional transmission clutch is open and torque transmission is interrupted in the conventional path, the hydraulic system maintains continuous torque delivery, preventing vehicle speed decrease and maintaining productivity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables faster torque buildup and improved drivability by maintaining turbo pressure and traction during gear changes, reducing speed loss and enhancing vehicle response to driver inputs, while being more energy-efficient and cost-effective than traditional power shift transmissions.
Implementation Method 1
a hydraulic transmission system, which at least comprises a pump, wherein said second wheel pair (5) is driven by said combustion engine over said hydraulic transmission system
Implementation Method 2
a combustion engine, a conventional transmission, a main clutch
Data Source
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AI summary
Method to control a drivetrain (1) of a vehicle, wherein said drivetrain (1) at least comprises a combustion engine (E), a conventional transmission (T), a main clutch (C), a hydraulic transmission system (hT), a first axle (2) with a first wheel pair (3) and a second axle (4) with a second wheel pair (5), wherein said hydraulic transmission system (hT) at least comprises a pump, and said first wheel pair (3) is driven by said combustion engine (E) over said conventional transmission (T), and said second wheel pair (5) is driven by said combustion engine (E) over said hydraulic transmission system (hT), wherein said pump of the hydraulic transmission system (hT) is driven directly by said combustion engine (T), said method is performed during driving of said vehicle, wherein : - a gear change is initialised in said conventional transmission (T), whereby - said pump is controlled, such that load torque (LTh) from said pump on the combustion engine (E) is increased, wherein said load torque (LTh) increase on the combustion engine (E) caused by the pump at least partially replaces a load torque (LTt) decrease caused by said gear change.