Hybrid Vehicle Torque Disturbance Mitigation via Controller Coordination

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Solution Overview

Problem

Hybrid vehicles experience driveline torque disturbances due to communication delays and varying response times between engine and motor torque controllers, leading to phase differences and objectionable torque fluctuations.

Innovation Solution

Implementing a method that commands engine torque within bounded limits based on accelerator pedal position during engine run-up, allowing for smooth torque progression and adjusting torque limits according to driver demand, thereby synchronizing engine and motor torque changes to minimize disturbances.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If engine torque is increased and motor torque is decreased simultaneously to provide driver demand torque, then the driver demand torque is met, but driveline torque disturbances occur due to phase differences between engine and motor torque responses

Engineering Contradiction:

Improvedriver demand torqueVSAvoiddriveline torque stability

Core Design Contradiction:

PowerVSStability of the object's composition

Solution Approach 1:

The system performs preliminary action by having the motor provide torque before the engine is fully closed and before the engine can respond to torque demands. The motor acts as a buffer during engine run-up, ensuring torque is available immediately while the engine is still accelerating from cranking speed, thus preventing torque disturbances during the transition phase

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The vehicle system controller continuously monitors engine torque and motor torque levels and adjusts their commands in real-time to maintain smooth transitions. The controller receives feedback on the phase difference between engine and motor responses and modifies torque distribution to minimize driveline disturbances, creating a closed-loop control system that adapts to varying engine and motor response characteristics

Inventive Principle:

Principle #23Feedback

2Adaptability or versatility

If engine torque commands and motor torque commands are processed with different delays due to communication network delays, then the control system can independently optimize each component, but phase differences develop causing driveline torque disturbances

Engineering Contradiction:

Improveindependent torque controlVSAvoidtorque response synchronization

Core Design Contradiction:

Adaptability or versatilityVSLoss of time

Solution Approach 1:

The system compensates for anticipated communication delays by issuing torque commands in advance. The motor controller receives and executes torque commands before the engine controller, effectively pre-synchronizing their responses. This preliminary timing adjustment accounts for the known processing and communication delays, ensuring both components respond in a coordinated manner despite different processing speeds

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The vehicle system controller acts as an intermediary that coordinates between the motor controller and engine controller. It receives the driver demand torque request and intelligently distributes torque commands to both components, timing them to account for their different response characteristics and communication delays, thus mediating the synchronization issue between the two controllers

Inventive Principle:

Principle #24Intermediary (Mediator)

3Stability of the object's composition

If heavily filtered engine torque commands are used during engine start, then driveline torque disturbances are reduced, but driveline torque response is slowed

Engineering Contradiction:

Improvedriveline torque smoothnessVSAvoiddriveline torque response speed

Core Design Contradiction:

Stability of the object's compositionVSSpeed

Solution Approach 1:

The system dynamically adjusts the filtering level of engine torque commands based on real-time operating conditions. During early engine run-up when smoothness is critical, heavier filtering is applied. As the engine approaches operational speed and the clutch begins to close, the filtering is reduced to improve response. This dynamic adaptation of filtering intensity allows the system to optimize both smoothness and response speed at different stages of the engine start sequence

Inventive Principle:

Principle #15Dynamics

4Speed

If engine torque limits are increased during high driver demand, then driveline torque response is improved, but the risk of torque disturbances increases

Engineering Contradiction:

Improvedriveline torque responseVSAvoidtorque disturbance risk

Core Design Contradiction:

SpeedVSObject-affected harmful factors

Solution Approach 1:

The system dynamically adjusts engine torque limits based on the phase of engine operation and driver demand. During engine run-up, torque limits are carefully bounded to prevent disturbances. As the engine approaches operational speed and the clutch closes, the torque limits are increased to improve response to driver demand. This dynamic adjustment of torque boundaries allows the system to maximize response speed while maintaining safety margins that prevent torque disturbances at critical transition phases

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS9802602B2Methods and system for mitigating engine and motor torque disturbances of a hybrid vehicle

Publication Date: 2017.10.31 FORD GLOBAL TECH LLC

AI summary

Systems and methods for operating a transmission of a hybrid powertrain that includes a motor/generator are described. The systems and methods may improve engine starting during engine starts where little or larger driver demand torques are requested. In one example, engine torque may be commanded to a torque based on a filtered driver demand torque, the filtered driver demand torque filtered based on a position of an accelerator pedal.