Hybrid Vehicle Electric Machine Starting Method
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Hybrid vehicles face challenges in starting a cold internal combustion engine due to the high torque required, which traditional starter motors can provide but electric machines struggle with, leading to complex solutions like servo-controlled gearboxes or clutch systems that are either inefficient or stressful on components.
Innovation Solution
A method involving a servo-controlled transmission with a reversible electric machine and a control unit that adjusts the launch rotation speed and overload of the electric machine based on engine temperature, allowing the electric machine to generate high torque by increasing current intensity and speed when starting a cold engine, reducing stress on components by adapting to the engine's temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the electric machine is mechanically connected to the drive shaft with a low gear-down ratio, then the hybrid vehicle structure is simplified, but the electric machine cannot generate the high starting torque needed to start a cold thermal engine
Solution Approach 1:
The patent applies dynamics by making the gear-down ratio variable rather than fixed. The transmission system automatically selects between a first high gear-down ratio for starting cold engines and a second low gear-down ratio for normal operation. This dynamic adaptation allows the same mechanical connection to provide both high torque multiplication when needed and direct connection during normal operation, resolving the contradiction between structural simplicity and torque capability.
2Force
If a servo-controlled gearbox is interposed between the electric machine and drive shaft to provide high gear-down ratio, then the starting torque is sufficient, but the constructional complexity increases
Solution Approach 1:
The patent applies universality by designing a transmission system that serves multiple functions: it provides high gear-down ratio for cold engine starting, low gear-down ratio for normal operation, and automatically selects between these modes. This multi-functional transmission eliminates the need for separate dedicated starting motors or complex servo-controlled systems, achieving both sufficient starting torque and acceptable structural complexity through a single integrated system.
3Force
If the electric machine is disconnected and idled before closing the clutch to exploit inertia, then high starting torque can be applied, but mechanical stresses increase and time delay occurs
Solution Approach 1:
The patent applies preliminary action by pre-charging the capacitor with energy before the starting operation. This stored electrical energy is then available immediately when needed to drive the electric machine as a starter motor, eliminating the need to idle the machine first to build up inertia. The preliminary energy storage allows direct engagement without excessive mechanical stress or time delay, resolving the contradiction between torque delivery and harmful effects.
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 rapid and effective starting of the thermal engine in both cold and warm conditions without excessively stressing transmission components, by dynamically adjusting torque and speed based on engine temperature, thus improving starting efficiency and reducing mechanical stress.
Implementation Method 1
an electric machine which is electrically connected to an electric storage system and mechanically connected to the driving wheels
Implementation Method 2
an internal combustion engine of a hybrid vehicle
Implementation Method 3
the electric machine may be used as a generator for a regenerative deceleration in which the kinetic energy possessed by the vehicle is partially converted into electricity
Data Source
AI summary
A method for starting an internal combustion thermal engine of a hybrid vehicle having: the thermal engine provided with a drive shaft; at least one pair of driving wheels; a transmission, which transmits the motion from the thermal engine to the driving wheels and has a clutch; and an electric machine, which is mechanically connected to the clutch downstream of the clutch, so that the clutch is interposed between the electric machine and the thermal engine; the starting method includes the steps of: opening the clutch to separate the electric machine from the thermal engine; separating the electric machine from the driving wheels; making the electric machine rotate by operating the electric machine as a motor; and closing the clutch when the electric machine reaches a launch rotation speed.