Integrated Starter Generator Engine Start Control

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

The existing systems with a driveline disconnect clutch and integrated starter/generator face challenges in reducing engine starting time and improving torque response, as the integrated starter/generator takes longer to accelerate the engine to cranking speed and may cause driveline torque disturbances when starting the engine.

Innovation Solution

The method involves stopping the engine rotation via a controller and shifting the transmission to neutral, then using the integrated starter/generator to rotate the engine to the expected input shaft speed of the transmission immediately after a power-on downshift, allowing the starter/generator to utilize its full power capacity for faster engine acceleration and reducing driveline torque disturbances.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If the integrated starter/generator is used to propel the vehicle while providing torque to start the engine, then the engine can be started, but the integrated starter/generator takes a greater amount of time than desired to accelerate the engine to cranking speed

Engineering Contradiction:

Improveengine cranking speedVSAvoidengine starting time

Core Design Contradiction:

SpeedVSLoss of time

Solution Approach 1:

The transmission is shifted to neutral before the engine start sequence begins, which isolates the engine from the driveline load. This preliminary action allows the integrated starter/generator to accelerate the engine without the resistance of driveline components, reducing the time to reach cranking speed

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The driveline disconnect clutch is engaged to disconnect the engine from the driveline during the engine start sequence. This extraction of the engine from the driveline system eliminates the load that would otherwise slow down engine acceleration, enabling faster startup

Inventive Principle:

Principle #2Taking out (Extraction)

2Power

If the integrated starter/generator provides torque to start the engine, then the engine can be started, but vehicle torque response is less than expected since the integrated starter/generator operates close to or at its power output capacity

Engineering Contradiction:

Improvevehicle torque outputVSAvoidtorque response time

Core Design Contradiction:

PowerVSProductivity

Solution Approach 1:

The transmission is shifted to neutral and the driveline disconnect clutch is engaged before the engine start sequence, preliminarily isolating the driveline from the engine. This allows the integrated starter/generator to operate at full power capacity for engine acceleration without simultaneously needing to provide vehicle propulsion torque, enabling faster torque response after startup

Inventive Principle:

Principle #10Preliminary action

3Stability of the object's composition

If the integrated starter/generator accelerates the engine to match the transmission input shaft speed, then driveline torque disturbances can be reduced, but the engine starting time increases

Engineering Contradiction:

Improvedriveline torque stabilityVSAvoidengine starting time

Core Design Contradiction:

Stability of the object's compositionVSLoss of time

Solution Approach 1:

The transmission is shifted to neutral and the driveline disconnect clutch is engaged before the engine acceleration sequence. This preliminary disconnection allows the engine to be accelerated to the target speed without driveline constraints, and the clutch is then smoothly engaged to minimize torque disturbances

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The driveline disconnect clutch is used to dynamically control the connection between the engine and driveline. The clutch is engaged at an optimal moment when engine speed matches the expected transmission input shaft speed, creating a smooth transition that minimizes torque disturbances while maintaining efficient startup timing

Inventive Principle:

Principle #15Dynamics

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 approach reduces engine starting time, improves driveline torque response, and minimizes the possibility of driveline torque disturbances, leading to enhanced vehicle drivability and smoother power delivery.

Implementation Method 1

rotating the engine via an integrated starter/generator to an expected input shaft speed of the transmission

Methodology Applied

Scientific EffectElectromagnetic conversion: Electromagnetic Induction

Data Source

PatentUS11400913B2Method and system for starting an engine

Publication Date: 2022.08.02 FORD GLOBAL TECH LLC

AI summary

A method and system for operating a vehicle that includes a driveline disconnect clutch and a step-ratio transmission is described. In one example, the method includes shifting the step-ratio transmission to neutral and accelerating an engine to an expected input shaft speed of the step-ratio transmission via applying full output capacity of an electric machine to the engine.