Hybrid Vehicle Mode Switching Control via Clutch Slip
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Solution Overview
Problem
Existing hybrid driving devices lack an effective control apparatus to efficiently switch between electric running mode (EV) and hybrid running mode (HEV), which affects the transmission of driving force to the wheels and overall vehicle performance.
Innovation Solution
A control apparatus for a hybrid vehicle that includes a transmission with multiple power transmitting paths through frictional engagement elements, allowing selective slipping of these elements during mode transitions from EV to HEV, enabling precise control of driving force by varying torque capacity through clutches between the engine and motor-generator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If frictional engagement elements are engaged to transmit power from engine to motor-generator during mode transition, then hybrid running mode is achieved, but shock and torque variation occur due to abrupt engagement
Solution Approach 1:
The control apparatus pre-charges the frictional engagement elements before full engagement by gradually increasing torque transmission from a predetermined state, allowing smooth transition from EV to HEV mode without shock or torque variation
Solution Approach 2:
The system dynamically adjusts the torque capacity of frictional engagement elements during mode transition, varying the degree of engagement to smoothly control power transmission from engine to motor-generator, achieving seamless mode switching
2Ease of operation
If clutch torque capacity is varied to control power transmission during mode transition, then driving force control is improved, but complex control mechanisms are required
Solution Approach 1:
The control apparatus uses feedback from rotational speed sensors and torque sensors to automatically adjust clutch torque capacity, simplifying the control mechanism while achieving precise driving force control during mode transitions
Solution Approach 2:
The system replaces complex mechanical control mechanisms with electronic control of clutch torque capacity based on predetermined transition states, simplifying the overall control apparatus while maintaining precise driving force control
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 transitions between EV and HEV modes, improving driving force control and reducing shock and torque variation, thereby enhancing vehicle performance and fuel efficiency.
Implementation Method 1
a clutch disposed between the engine and the motor-generator configured to vary a transmitted torque capacity
Implementation Method 2
a transmission disposed between the motor-generator and at least one driving wheel having at least two power transmitting paths through the selective engagement of at least one of a plurality of frictional engagement elements
Data Source
AI summary
A control apparatus for a hybrid vehicle for controlling and limiting the transmission of power from an engine to the driving wheels during start-up of the engine to produce a hybrid running mode where the vehicle is powered by both the engine and a motor-generator. During start-up of the engine, a first frictional element changing its state before and after a shift of the transmission is allowed to slip, and a second frictional element is allowed to slip. The element that is allowed to slip is switched from one to the other.