Hybrid Drive Control Device Engine Starting Reaction Force Reduction
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Solution Overview
Problem
Conventional hybrid vehicle drive systems experience a significant reaction force during engine starting when the electric motor is primarily used for propulsion, which cannot be effectively reduced, impacting vehicle performance and drivability.
Innovation Solution
A drive control device with a first and second differential mechanism, connected through a clutch and brake, where the brake is engaged to fix a rotary element to a stationary member, and the first electric motor increases engine speed while the second electric motor reduces the reaction force on the output rotary member during engine starting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the electric motor is used as the primary drive power source and the engine is held at rest, then energy efficiency is improved, but a reaction force is generated on the output side when the engine is started
Solution Approach 1:
The patent introduces a reaction force reduction mechanism that includes a reaction force reduction wheel, reaction force reduction pinion, and reaction force reduction motor. This intermediary system is configured to generate a reaction force that opposes the harmful reaction force generated during engine starting, thereby reducing the net reaction force transmitted to the output shaft while allowing the engine to start smoothly in the hybrid vehicle where the electric motor is the primary drive source
Solution Approach 2:
The reaction force reduction motor generates a counteracting torque that functions as a counterweight to the harmful reaction force. By controlling the reaction force reduction motor to produce an opposing rotational force, the system effectively neutralizes the adverse reaction force that would otherwise be transmitted to the output side during engine starting, solving the contradiction between maintaining energy efficiency and eliminating harmful forces
2Stability of the object's composition
If the brake is engaged to fix the engine output shaft, then the engine can be held at rest for energy efficient operation, but the reaction force cannot be reduced during engine starting
Solution Approach 1:
The patent segments the braking function into two independent systems: the main brake mechanism that holds the engine output shaft stationary during energy-efficient operation, and the separate reaction force reduction mechanism that activates during engine starting. This segmentation allows the brake to maintain engine stability while the reaction force reduction motor independently manages the starting reaction force, resolving the contradiction between maintaining stationary position and reducing starting forces
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 configuration effectively reduces the reaction force generated during engine starting, enhancing the hybrid vehicle's performance and drivability by mitigating the deceleration effect felt by the operator.
Implementation Method 1
operating the above-described first electric motor to raise a speed of a rotary motion of the above-described engine
Implementation Method 2
operating the above-described second electric motor to reduce a reaction force which is generated during starting of the above-described engine and which acts on the above-described output rotary member
Implementation Method 3
one of the rotary elements of the above-described first and second differential mechanisms which are selectively connected to each other through the above-described clutch is selectively fixed to a stationary member through a brake
Data Source
AI summary
A drive control device for a hybrid vehicle is provided with a differential device having four rotary elements. One of the four rotary elements is constituted by rotary components of each of a first and a second differential mechanisms selectively connected to each other through a clutch. One of the rotary components of said first and second differential mechanisms selectively connected through said clutch is selectively fixed to a stationary member through a brake. The drive control device comprises a brake engagement control portion configured to place the brake in an engaged state upon starting an engine, and an electric motor operation control portion configured to operate a first electric motor to raise a speed of a rotary motion of the engine for starting of the engine and to operate a second electric motor to reduce a reaction force during starting of said engine acting on an output rotary member.