Hybrid Engine Auto-Start Speed Profile Synchronization
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Solution Overview
Problem
In hybrid vehicles, combustion assisted auto-starts lead to inefficiencies due to differing engine speed targets between the hybrid system controller and the engine controller, resulting in inefficient engine operation.
Innovation Solution
A method where the hybrid system controller defines a rotational engine speed profile based on current vehicle conditions, communicated to the engine controller, with a spark correction offset calculated using a flare control algorithm to synchronize both controllers' targets, ensuring efficient engine starting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a combustion assisted auto-start is used where the engine is fueled and fired as soon as the electric motor begins to spin the engine, then the engine can start producing torque more quickly, but the hybrid system controller and engine controller define different desired engine speeds creating system inefficiency
Solution Approach 1:
The patent merges the control functions of the hybrid system controller and engine controller by having both controllers use the same rotational engine speed profile. The hybrid system controller generates the speed profile based on vehicle conditions, and the engine controller receives and executes this profile, ensuring both controllers target the same engine speed and eliminating conflicting control commands.
Solution Approach 2:
The patent implements feedback by continuously monitoring the actual engine speed and comparing it to the desired speed profile. The engine controller calculates a spark correction offset based on the deviation between actual and desired speeds, and adjusts spark timing accordingly to bring the engine speed back in line with the target profile.
2Device complexity
If the engine controller uses a flare control algorithm with a single calibration table to define desired engine speed, then the control implementation is simplified, but it creates a conflict with the hybrid system controller's speed targets resulting in inefficient engine operation
Solution Approach 1:
The patent transitions from a static single calibration table to a dynamic rotational engine speed profile that is continuously adjusted based on current vehicle operating conditions. The hybrid system controller generates this dynamic profile considering factors like vehicle speed, acceleration demands, and battery state of charge, allowing the desired engine speed to adapt in real-time rather than being fixed by a single calibration table.
Solution Approach 2:
The rotational engine speed profile serves multiple functions: it acts as the target speed for the electric motor to achieve, guides the flare control algorithm's spark timing adjustments, and ensures coordination between the hybrid system controller and engine controller. This single multi-functional profile replaces the need for separate calibration tables in both controllers.
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 method synchronizes the engine speed targets of the hybrid system controller and engine controller, improving the efficiency of combustion assisted auto-starts by minimizing conflicts and disturbances, thus enhancing overall vehicle performance.
Implementation Method 1
The internal combustion engine is rotated with an electric propulsion motor of the hybrid vehicle, to increase a rotational speed of the internal combustion engine
Implementation Method 2
A spark correction offset is calculated with the engine controller based on a deviation between an actual rotational speed of the internal combustion engine and the rotational engine speed profile
Data Source
AI summary
A method of automatically starting an internal combustion engine of a hybrid vehicle includes defining a rotational engine speed profile to represent a desired engine speed during a starting event with a hybrid system controller, and communicating the rotational engine speed profile to an engine controller. The internal combustion engine is rotated with an electric propulsion motor of the hybrid vehicle. A spark correction offset is calculated with the engine controller based on the rotational engine speed profile. The internal combustion engine is fired with the calculated spark correction offset for a pre-determined number of firing events, with the engine controller, as the rotational speed of the engine increases. The rotational speed of the internal combustion engine is controlled with the hybrid system controller after the pre-determined number of firing events.