Hybrid Drive Clutch Torque Control for Engine Start

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

In parallel hybrid vehicles, the existing clutch control systems face challenges in synchronizing the internal combustion engine and electric machine efficiently, leading to increased starting time, energy consumption, and clutch wear due to manufacturing tolerances, temperature changes, and aging effects, which result in insufficient or unreliable engine start-ups.

Innovation Solution

The implementation of a proportional clutch between the internal combustion engine and electric machine, with a controlled slip torque mechanism that adjusts based on real-time conditions, including a timer and correction factors to ensure successful engine start-ups while minimizing torque requirements and wear, and the use of characteristic maps to store setpoint values for varying operating parameters.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the additional clutch is closed to start the internal combustion engine, then the engine can be brought to the required speed, but the torque required to accelerate the engine increases energy consumption from the electric machine

Engineering Contradiction:
Improveengine start-up reliabilityVSAvoidenergy consumption of electric machine
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The clutch torque is dynamically adjusted during the start-up process. The control device determines a first clutch torque for accelerating the internal combustion engine and a second clutch torque for synchronizing the clutch. The torque transitions from a higher acceleration phase to a lower synchronization phase, optimizing energy usage while ensuring reliable engine start-up.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The control device determines operating parameters of the internal combustion engine before the actual start-up occurs. Based on these pre-determined parameters, the appropriate clutch torque is calculated in advance, allowing the engine to be accelerated efficiently to the required speed with minimal energy consumption from the electric machine.

Inventive Principle:
Principle #10Preliminary action

2Device complexity

If a fixed clutch torque is used to accelerate the internal combustion engine, then the start-up process is simple, but it cannot compensate for manufacturing tolerances, temperature changes, and aging effects

Engineering Contradiction:
Improveclutch control complexityVSAvoidengine start-up reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The control device continuously determines operating parameters of the internal combustion engine during the start-up process and adjusts the clutch torque accordingly. This feedback mechanism compensates for manufacturing tolerances, temperature changes, and aging effects, ensuring reliable engine start-up while adapting to varying conditions without requiring overly complex hardware.

Inventive Principle:
Principle #23Feedback

3Reliability

If the clutch torque is increased to ensure sufficient acceleration, then the engine starts more reliably, but the torque required from the electric machine increases

Engineering Contradiction:
Improveengine start-up reliabilityVSAvoidtorque requirement of electric machine
Core Design Contradiction:
ReliabilityVSPower

Solution Approach 1:

The clutch torque is applied in distinct phases: a first clutch torque for acceleration and a second clutch torque for synchronization. This periodic application of torque ensures the engine starts reliably during the acceleration phase while reducing the torque requirement during the synchronization phase, optimizing the power demand on the electric machine.

Inventive Principle:
Principle #19Periodic action

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 optimizes the clutch process by ensuring quick and reliable engine start-ups, reducing energy consumption and clutch wear, and adapting to changing conditions such as temperature and aging, thereby enhancing the overall efficiency and performance of the hybrid drive system.

Implementation Method 1

A second clutch (3) arranged between the internal combustion engine (2) and the electric machine (4). This is preferably a proportional clutch.

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP2079621B1Method for controlling a hybrid drive
Publication Date: 2021.06.30 ROBERT BOSCH GMBH
  • EP2079621B1 patent drawingFigure 1
  • EP2079621B1 patent drawingFigure 2~3
  • EP2079621B1 patent drawingFigure 4~5

AI summary

The invention relates to a method for controlling at least one internal combustion engine (2) and at least one hybrid drive (1) of a vehicle (100) comprising an electric motor (4), with a first coupling disposed between the electric motor (4) and the drive train (6) of the vehicle (100) and a second coupling (3) disposed between the electric motor (4) and the internal combustion engine (2). The method is characterized in that to the second coupling (3) a predetermined coupling moment is applied in order to start the internal combustion engine (2) by the operating electric motor (4), that the rotational speed NV of the internal combustion engine (2) is monitored, and that the coupling moment is incremented to a higher value if the rotational speed NV of the internal combustion engine (2) falls below a predetermined threshold value within a predetermined time interval.