Hybrid Powertrain Engine Start via Planetary Gear Decoupling

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Solution Overview

Problem

Prior art hybrid powertrain systems are inefficient during transitions between operating modes, particularly when switching from low-load to high-load modes, especially in vehicles with heavy duty diesel engines, leading to rough engine starts and inefficient energy transfer.

Innovation Solution

A hybrid powertrain system incorporating a first prime mover, a second prime mover, a synchronizing clutch, a multi-ratio transmission, and a planetary gear set, where the planetary gear set is decoupled from the multi-ratio transmission input as the first prime mover is started and accelerated to match the velocity of the transmission input, allowing smooth transitions and energy transfer without negative driveline torque.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the diesel engine is started in prior art hybrid powertrain systems, then the engine transitions from low-load to high-load mode, but the transition is rough and inefficient particularly in heavy duty diesel engines

Engineering Contradiction:

Improvetransition efficiencyVSAvoidsmoothness of engine start

Core Design Contradiction:

ProductivityVSEase of operation

Solution Approach 1:

The planetary gear set is decoupled from the multi-ratio transmission input before the engine start process begins. This preliminary decoupling prevents negative driveline torque from affecting the transmission during engine cranking and acceleration, allowing the engine to reach operating velocity smoothly before re-engaging with the transmission.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The powertrain system is segmented into distinct coupling states: the planetary gear set can be decoupled from the transmission input during engine start, and the synchronizing clutch can selectively couple or decouple prime movers. This segmentation allows independent control of engine starting from transmission loading, resolving the contradiction between transition efficiency and smoothness.

Inventive Principle:

Principle #1Segmentation

2Power

If the planetary gear set is coupled to the transmission input during engine start, then power transfer is maintained, but negative driveline torque occurs causing rough engine start

Engineering Contradiction:

Improvepower transfer continuityVSAvoidnegative driveline torque

Core Design Contradiction:

PowerVSObject-generated harmful factors

Solution Approach 1:

The harmful effect of negative driveline torque is extracted from the system by decoupling the planetary gear set from the multi-ratio transmission input during engine start. This separation removes the transmission loading that would otherwise create negative torque during engine cranking, eliminating the harmful factor while maintaining power transfer capability through alternative paths via the synchronizing clutch.

Inventive Principle:

Principle #2Taking out (Extraction)

3Power

If heavy duty diesel engines are used in hybrid powertrain systems, then high power output is achieved, but the transition between operating modes becomes notably rough

Engineering Contradiction:

Improveengine power outputVSAvoidoperational smoothness

Core Design Contradiction:

PowerVSStability of the object's composition

Solution Approach 1:

The system dynamically adjusts the coupling state of the planetary gear set and synchronizing clutch based on operating conditions. During engine start transitions, the planetary gear set is decoupled from the transmission input while the synchronizing clutch manages power flow between prime movers. This dynamic reconfiguration allows heavy duty diesel engines to transition smoothly between operating modes while maintaining high power output capability.

Inventive Principle:

Principle #15Dynamics

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

Enables smooth and efficient transitions between operating modes, reducing the roughness of engine starts in heavy duty diesel engines and optimizing energy transfer, making the powertrain system more efficient and comfortable for vehicle operators.

Implementation Method 1

a planetary gear set operatively coupling the second prime mover output to the first prime mover output or the multi-ratio transmission input based on a coupling state of the synchronizing clutch

Methodology Applied

Scientific EffectGear: Gear

Implementation Method 2

a synchronizing clutch selectively coupling the first prime mover output and the second prime mover output

Methodology Applied

Scientific EffectFriction: Friction

Data Source

PatentUS7367415B2Hybrid electric vehicle engine start technique

Publication Date: 2008.05.06 EATON INTELLIGENT POWER LTD

AI summary

A hybrid powertrain system includes a first prime mover having an output, a second prime mover having an output, a synchronizing clutch selectively coupling the first prime mover output and the second prime mover output, a multi-ratio transmission having an input, and a planetary gear set selectively coupling the second prime mover output to the first prime mover output or the multi-ratio transmission input based on a coupling state of the synchronizing clutch.