Hybrid Drive Torque Control Using Second Electric Machine
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Solution Overview
Problem
Hybrid vehicle drives face challenges in transient operation due to delayed response of internal combustion engines, particularly in turbocharged gasoline engines, where the dynamic setting of air mass flow and torque is limited, leading to inefficiencies and increased fuel consumption and emissions.
Innovation Solution
The implementation of a second electric machine that generates drive torque independently and is activated with a time delay to support the first electric machine and internal combustion engine, allowing for cumulative torque and efficient all-wheel drive dynamics, with control devices calculating target torques based on operating states and sensor parameters to optimize efficiency and prevent overloading.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the internal combustion engine is used to generate torque, then the vehicle propulsion is achieved, but the response time is delayed due to turbo lag and limited air path dynamics
Solution Approach 1:
The patent introduces an electric machine as an intermediary component between the driver's torque demand and the internal combustion engine. The electric machine responds instantaneously to transient torque demands, bridging the response gap caused by the slow air path dynamics of the internal combustion engine, while the engine handles steady-state propulsion.
Solution Approach 2:
The electric machine is activated in advance during transient operation to provide immediate torque support before the internal combustion engine can respond. This preliminary action compensates for the delayed engine response, ensuring smooth and rapid torque delivery during acceleration or load changes.
2Productivity
If the electric machine is activated to compensate for transient operation, then the response dynamics are improved, but the system reaches its torque limits and cannot provide further compensation
Solution Approach 1:
The patent combines the torque capabilities of the internal combustion engine and the electric machine into a unified hybrid drive system. By merging their torque outputs, the system achieves a cumulative torque that exceeds what either component could deliver alone, enabling the vehicle to meet high transient torque demands that would overwhelm the electric machine by itself.
3Power
If the internal combustion engine operates in transient mode to meet torque specifications, then the torque demand is satisfied, but fuel consumption and exhaust gas emissions increase due to reduced efficiency
Solution Approach 1:
The electric machine provides partial torque during transient operation, covering only the portion of torque demand that requires rapid response. The internal combustion engine handles the remaining torque at its optimal operating point, avoiding excessive fuel consumption and emissions that would result from operating the engine in inefficient transient modes.
4Reliability
If a single electric machine is used to support the internal combustion engine, then transient operation is compensated, but the drive train dynamics are limited by the system capacity of that single machine
Solution Approach 1:
The patent segments the electric machine function into two independent units: a first electric machine coupled with the internal combustion engine for primary transient support, and a second electric machine providing additional independent torque contribution. This segmentation allows each machine to operate within its optimal capacity range while collectively providing enhanced transient response and drive train dynamics.
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 solution enhances the dynamics and efficiency of the hybrid drive during transient operation, maintaining drive train dynamics beyond the system limits of individual electric machines, reducing energy consumption, and optimizing energy recovery and distribution for improved propulsion and reduced risk of damage.
Implementation Method 1
an electric machine supports the combustion engine in achieving a torque specification of the hybrid drive more quickly
Implementation Method 2
at least one second electric machine is provided, which generates a drive torque that is summed up in transient operation together with the drive torques of the internal combustion engine and the first electric machine
Implementation Method 3
the drive train of the motor vehicle usually has an internal combustion engine
Data Source
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AI summary
The invention relates to a method for operating a hybrid drive (1) of a motor vehicle, which comprises an internal combustion engine (3) and a first electric motor (5), said hybrid drive (1) at a default setpoint torque (MSoll, F) generating a sum torque (MGes, Ist) driving the motor vehicle, wherein in a non-steady operating mode occurring during a change in the default setpoint torque (MSoll, F) by a value (?MSoll), the sum torque (MGes, Ist) is generated by adding a drive torque (M1, Ist) generated by the internal combustion engine (3) and a drive torque (M2, Ist) generated by the first electric motor (5). According to the invention at least one second electric motor (7) is provided, which is switched on during the non-steady operating mode for generating the sum torque (MGes, Ist) of the internal combustion engine (3) and the first electric motor (5).