Powertrain Hydraulic Cooling Branch Control for Balanced Oil Flow

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Solution Overview

Problem

Existing cooling systems in vehicle powertrains often supply cooling oil beyond the requirements of individual components, leading to inefficient operation due to temperature imbalances among parts, resulting in reduced efficiency.

Innovation Solution

A hydraulic system with integrated cooling branches and control elements, including proportional adjustment solenoid valves, that allow independent flow control for each component, adjusting cooling flow based on demand through a controller that calculates rotational speeds and opening degrees of valves.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If cooling oil paths of multiple parts are controlled by a single pump through throttle valves, then the system structure is simple, but the cooling flow distribution cannot meet the specific demands of each part, resulting in some parts operating outside efficient temperature range

Engineering Contradiction:
Improvecooling flow distribution controlVSAvoidhydraulic system structure
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent divides the single cooling oil path into multiple independent cooling branches (first cooling branch, second cooling branch, third cooling branch, fourth cooling branch), each serving specific components. This segmentation allows independent flow control for each component, enabling precise cooling flow distribution to meet specific thermal demands of different parts.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent replaces fixed throttle valves with dynamically controllable electro-hydraulic proportional valves and solenoid valves on each cooling branch. These dynamic valves can adjust opening degrees based on real-time temperature and flow requirements, transforming the static cooling system into a dynamic one that adapts to changing thermal demands of various components.

Inventive Principle:
Principle #15Dynamics

2Manufacturing precision

If throttle valves are used to distribute cooling flow, then the system is easy to manufacture, but the cooling flow rate cannot be precisely adjusted for each component, leading to excessive cooling for some parts and insufficient cooling for others

Engineering Contradiction:
Improvecooling flow rate control precisionVSAvoidvalve control system
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent replaces traditional mechanical throttle valves with electro-hydraulic proportional valves and solenoid valves that can be controlled by electrical signals from the controller. This substitution enables precise electronic control of cooling flow rates for each branch, allowing accurate adjustment based on real-time temperature feedback and component requirements, significantly improving flow control precision.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent implements a feedback control system where temperature sensors monitor the temperature of each component, and the controller adjusts the opening degrees of proportional valves and solenoid valves based on this feedback. This closed-loop feedback mechanism ensures precise cooling flow rate adjustment, maintaining each component within its optimal temperature range.

Inventive Principle:
Principle #23Feedback

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

Ensures each powertrain component operates within an efficient temperature range, optimizing cooling flow distribution and enhancing system efficiency by minimizing flow loss.

Implementation Method 1

a first oil pump and a cooler are arranged on the main cooling oil path. The first oil pump is configured to pump an oil in the oil tank to the cooling branches

Methodology Applied
Scientific EffectHydraulic pressure: Pressure Gradient

Implementation Method 2

a first oil pump and a cooler are arranged on the main cooling oil path

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 3

A control element is arranged on each of the cooling branches. The control element is configured to control opening and closing of the corresponding cooling branch

Methodology Applied
Scientific EffectValve control: Valve

Implementation Method 4

A hydraulic system with integrated cooling branches and control elements, including proportional adjustment solenoid valves, that allow independent flow control for each component

Methodology Applied
Scientific EffectSolenoid actuation: Solenoid

Implementation Method 5

a second oil pump and a pressure control solenoid valve are arranged on the driving oil path, the second oil pump is configured to pump the oil to the driving oil path

Methodology Applied
Scientific EffectHydraulic pressure: Pressure Gradient

Implementation Method 6

the driving oil path is configured to control engagement and disengagement of the clutch

Methodology Applied
Scientific EffectPressure control: Valve

Data Source

PatentEP4299920B1Vehicle, hydraulic system for powertrain of vehicle, and control method therefor
Publication Date: 2025.06.25 BYD CO LTD
  • EP4299920B1 patent drawingFigure 1~2
  • EP4299920B1 patent drawingFigure 3~4
  • EP4299920B1 patent drawingFigure 5~8

AI summary

A vehicle, a hydraulic system (100) for a powertrain of a vehicle, and a method for controlling same. The hydraulic system (100) for a powertrain of a vehicle includes an oil tank (10), a main cooling oil path (m), and a plurality of cooling branches. One end of the main cooling oil path (m) is communicated with the oil tank (10). A first oil pump (20) and a cooler (30) are arranged on the main cooling oil path (m). The plurality of cooling branches are connected to another end of the main cooling oil path (m). The first oil pump (20) is configured to pump an oil in the oil tank (10) to the cooling branches. An independently controlled control element is arranged on each of the plurality of cooling branches. The control element is configured to control opening and closing of the corresponding cooling branch. The plurality of cooling branches are configured to cool at least one of a drive motor (50a), a generator (50d), a clutch (50b), and a transmission system (50c).