Hybrid Vehicle Drive Control for Faster Engine Mode Transitions
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Solution Overview
Problem
The existing vehicle drive devices face inefficiencies in transitioning between operation modes, particularly in starting the internal combustion engine during mode changes, leading to increased time requirements due to the need for multiple state changes of engagement devices and waiting for rotational speed adjustments.
Innovation Solution
A vehicle drive device configuration with a distribution differential gear mechanism and control device that allows for controlled rotational speed adjustments of the first rotary element, enabling the internal combustion engine to be started using drive power from the rotary electric machine without changing the engagement device states, thereby reducing transition time between modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the internal combustion engine is started by the first start control (changing third engagement devices from engaged to disengaged states), then the engine can be started, but the number of times of changing the states of the engagement devices increases and the transition time becomes longer
Solution Approach 1:
The control device performs preliminary action by controlling the rotational speed of the first rotary element to approach the target rotational speed required for engine starting, before actually starting the engine. This preparation eliminates the need for intermediate engagement device state changes during the starting process, reducing transition time.
Solution Approach 2:
The invention extracts the rotational speed adjustment function from the engagement device state changes. By independently controlling the rotational speed of the first rotary element through the rotary electric machine, the system separates the speed matching requirement from the engagement device operation, allowing engine starting without changing engagement device states.
2Loss of time
If the internal combustion engine is started by the second start control (maintaining all engagement devices in engaged states), then the number of engagement device state changes is reduced, but the rotational speed of the first rotary element must be pre-adjusted to the target speed
Solution Approach 1:
The control device changes the rotational speed parameter of the first rotary element by controlling the rotary electric machine's output. This parameter adjustment is performed continuously and smoothly while maintaining engagement devices in their current states, enabling the system to meet the target rotational speed requirement without complex state changes.
3Reliability
If the rotational speed of the first rotary element is adjusted by waiting for mode transition, then the engine can be started at the correct speed, but the transition time becomes longer
Solution Approach 1:
The invention replaces the mechanical waiting process with active rotational speed control through the rotary electric machine. Instead of passively waiting for the first rotary element to reach the target speed during mode transition, the control device actively drives the rotational speed to the target value, significantly reducing the time required while ensuring accurate starting conditions.
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 reduces the time required for transitioning between operation modes by allowing the internal combustion engine to be started efficiently using the rotary electric machine's drive power, without altering the engagement device states, thus enhancing operational efficiency.
Implementation Method 1
a rotary electric machine including a rotor... drive power of the rotary electric machine is transmitted to the first output member... the internal combustion engine can be started efficiently using the rotary electric machine's drive power
Data Source
AI summary
A control device that controls an internal combustion engine, a first rotary electric machine, a first engagement device, and a second engagement device performing first transition control when transition is performed from a first mode to a second mode. The first transition control includes first control, second control, and third control. The first control is control in which the second engagement device that connects and disconnects power transmission between two rotary elements selected from among three rotary elements of a distribution differential gear mechanism is changed from an engaged state to a disengaged state while a third engagement device of a transmission mechanism is maintained in an engaged state. The second control controls a rotational speed of the first rotary element to is changed from a disengaged state to an engaged state and the internal combustion engine is started by using drive power transmitted from the first rotary electric.