Hybrid Heat Engine Startup via Electric Drive Synchronization
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Solution Overview
Problem
The startup of a heat engine in hybrid vehicles results in significant polluting emissions, particularly when the catalytic converter has not yet been primed, leading to non-compliance with pollution reduction standards during the initial certification cycle.
Innovation Solution
The heat engine startup process is modified by coupling the two main shafts, inhibiting fuel injection, launching the heat engine with the electric machine, synchronizing speeds, activating fuel injection, and then decoupling the shafts, allowing the heat engine and electric machine to be synchronized at idle speed or higher.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the heat engine is started up using a conventional starter motor, then the startup process is simple and reliable, but significant polluting emissions are generated when the catalytic converter is not yet primed
Solution Approach 1:
The patent merges the function of the starter motor with the electric drive machine. The electric drive machine serves dual purposes: propelling the vehicle and starting the heat engine. This is achieved by coupling the electric drive machine to the heat engine's crankshaft through the transmission system, eliminating the need for a separate starter motor and reducing overall system complexity while lowering emissions.
Solution Approach 2:
The electric drive machine is designed to perform multiple functions: it acts as a motor for vehicle propulsion, a generator for energy recovery during braking, and a starter motor for engine ignition. This multi-functionality reduces the number of separate components needed in the hybrid powertrain system.
2Object-affected harmful factors
If the heat engine is started up with fuel injection activated, then the engine starts quickly, but fuel combustion during startup increases polluting emissions
Solution Approach 1:
The catalytic converter is pre-heated and primed before the heat engine startup using the electric drive machine. This preliminary action ensures the converter is ready to immediately process and reduce emissions once fuel combustion begins, minimizing the window of high pollution output during engine ignition.
Solution Approach 2:
The startup process uses periodic fuel injection pulses rather than continuous injection. The electric drive machine provides initial rotational force in periodic bursts, synchronized with intermittent fuel injection, allowing the engine to reach operating speed with minimal fuel consumption and reduced emissions.
3Object-affected harmful factors
If the catalytic converter is primed before startup, then emissions are reduced, but additional time and energy are required for priming
Solution Approach 1:
The electric drive machine, which is already operational during vehicle operation, uses its own excess capacity to prime the catalytic converter before engine startup. The system leverages the electric machine's existing energy output without requiring separate external energy sources or dedicated priming systems.
Solution Approach 2:
The catalytic converter priming process occurs continuously during the electric drive machine's operation before engine startup, rather than requiring a separate discrete priming phase. The converter is gradually heated and activated in parallel with normal vehicle operation, eliminating wasted time and energy.
4Productivity
If the heat engine and electric machine are synchronized at high speed, then startup performance is improved, but energy consumption increases
Solution Approach 1:
The synchronization speed between the heat engine and electric machine is dynamically adjusted based on real-time operating conditions. The system optimizes the synchronization point to achieve sufficient startup performance while minimizing energy consumption, adapting the target speed according to load requirements and battery state of charge.
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 polluting emissions by eliminating fuel combustion during startup speed increase, is quieter by avoiding the starter engagement, and reduces startup time with faster electric machine performance, effectively priming the catalytic converter for subsequent startups.
Implementation Method 1
launching the heat engine by means of the electric machine
Implementation Method 2
activating the fuel injection
Data Source
AI summary
A method controls the startup of a heat engine of a hybrid power train of a vehicle. The power train includes the heat engine and an electric drive machine, two concentric main shafts coupled one to the heat engine and one to the electric machine, at least one step-down gear of each of the main shafts on a secondary shaft connected to wheels of the vehicle, and a coupling of the two main shafts. The method includes coupling the two main shafts, inhibiting fuel injection of the heat engine, launching the heat engine by the electric machine, synchronizing a speed of the heat engine and a speed of the electric machine without fuel injection, activating the fuel injection and turning off the electric machine and decoupling the two main shafts.