Vehicle Drive Control Device for Hybrid Transmission
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Solution Overview
Problem
Existing drive apparatus for hybrid vehicles face challenges in minimizing size while improving fuel economy and suppressing vibration and noise during engine start-up and halt, due to the need for large electric motors and inefficiencies in power transmission.
Innovation Solution
A control apparatus with a differential mechanism that selectively switches between continuously variable and step-variable shifting states, using a differential state switch device and on-engine-start switching control means to optimize power transmission and engine speed management, thereby minimizing electric energy conversion losses and reducing vibration and noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If electric energy is used to transmit part of the vehicle drive force from the first electric motor to the second electric motor, then fuel consumption is improved, but the size of the drive apparatus increases due to larger electric motors
Solution Approach 1:
The patent applies dynamics by making the transmission system adaptable through switching between two operational modes: a first mode where the differential mechanism operates in a differential state allowing independent rotation of left and right drive wheels, and a second mode where it operates in a non-differential state with locked wheels. This dynamic switching capability allows the system to optimize between fuel efficiency and compact size based on driving conditions, resolving the contradiction between improved fuel consumption and reduced drive apparatus size.
2Adaptability or versatility
If the second electric motor is driven by electric energy from the first electric motor, then power transmission flexibility is improved, but the size of the second electric motor and drive apparatus increases
Solution Approach 1:
The patent applies universality by designing the differential mechanism to perform multiple functions: it can operate as a differential mechanism in the first operational mode, and as a locking mechanism in the second operational mode. This multi-functionality eliminates the need for separate dedicated components for each mode, allowing the system to achieve power transmission flexibility without increasing the size of the second electric motor or the overall drive apparatus.
3Loss of time
If engine speed is rapidly increased during start-up to transit resonating region, then engine start-up time is reduced, but vibration and noise increase due to resonating phenomenon
Solution Approach 1:
The patent applies skipping by deliberately controlling the engine speed to rapidly transit through the resonating region during start-up, minimizing the time spent in the harmful resonance zone. The control device manages the engine speed profile to quickly pass through the problematic speed range rather than lingering in it, thereby reducing vibration and noise while maintaining fast start-up performance.
Solution Approach 2:
The patent applies periodic action through the cyclic nature of engine combustion and the corresponding periodic control adjustments made during start-up. The control device modulates fuel injection and ignition timing in a periodic manner to manage engine speed progression through the resonating region, creating controlled oscillations that help the engine smoothly and quickly transit the problematic speed range.
4Loss of energy
If the differential mechanism operates in non-differential state with locked drive wheels, then power transmission efficiency is improved, but vehicle maneuverability decreases
Solution Approach 1:
The patent applies dynamics by enabling the differential mechanism to dynamically switch between differential and non-differential operational states based on driving conditions. When high power transmission efficiency is needed (such as during acceleration), the system locks the wheels in a non-differential state. When maneuverability is required (such as during turning), the system transitions to a differential state, allowing the wheels to rotate at different speeds. This dynamic adaptability resolves the contradiction between power transmission efficiency and vehicle maneuverability.
Data Source
AI summary
A drive apparatus for vehicle is disclosed having a coupling device (switching clutch B0 or switching brake C0) operative to switch a transmission mechanism 10 between a continuously variable shifting state and a step-variable shifting state with both advantages including improved fuel consumption achieved by a transmission, enabled to electrically control a speed ratio, and increased power transmitting efficiency provided by a gear-type transmitting device in which drive power is mechanically transmitted. With the transmission mechanism 10, switching control means 50 allows a differential portion 11 to be maintained in the continuously variable shifting state or the differential portion 11 is preferentially placed in the continuously variable shifting state during a start-up of an engine. This allows an engine speed NE to rapidly increase beyond a given engine speed NE′ to immediately transit a given engine speed area NER, thereby suppressing the occurrence of vibrational noise of the vehicle during the start-up of the engine.