Hybrid Engine Start Control via Fluid Temperature Thresholds
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Solution Overview
Problem
Hybrid electric vehicles (HEVs) face challenges in efficiently starting the engine for heating and transmission lubrication, as existing systems often rely on electric motors, which may not provide sufficient heat or lubrication, especially during initial start-ups or in cold conditions.
Innovation Solution
A system and method for initiating engine start in HEVs that considers fluid temperatures to determine energy demands, allowing the engine to start for the first time upon a vehicle drive start request, providing heat for cabin comfort and lubrication for powertrain elements, using a controller to manage the engine start based on predetermined temperature thresholds and operational conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the engine is started using existing systems that rely on electric motors, then the vehicle can operate in electric drive mode, but the electric motor may not provide sufficient heat for cabin heating or adequate lubrication for transmission elements
Solution Approach 1:
The system performs preliminary assessment of fluid temperatures (engine coolant, transmission fluid) before deciding to start the engine. This preliminary action allows the system to determine in advance whether engine starting is necessary to provide sufficient heat for cabin heating and adequate lubrication for transmission elements, rather than reacting after deficiencies occur.
Solution Approach 2:
The system continuously monitors fluid temperatures from sensors and uses this feedback to make real-time decisions about engine starting. The controller receives temperature data, compares it against thresholds, and adjusts engine operation accordingly to maintain both cabin heating requirements and transmission lubrication adequacy.
2Temperature
If the engine is started to provide heat for cabin heating, then passenger comfort is improved, but energy consumption increases
Solution Approach 1:
The system applies partial action by starting the engine only when absolutely necessary - specifically when fluid temperatures indicate that neither electric motor heating nor transmission lubrication can meet minimum requirements. The controller compares actual temperatures against thresholds and initiates engine starting only when the deficiency exceeds what alternative systems can provide, thereby avoiding unnecessary fuel consumption while maintaining passenger comfort when needed.
Solution Approach 2:
The system changes operational parameters by dynamically adjusting engine start decisions based on real-time temperature conditions. Rather than maintaining a fixed engine start strategy, the controller modifies engine operation parameters (start/stop timing, duration) according to varying cabin temperature requirements, transmission fluid temperature, and engine coolant temperature, optimizing the balance between comfort and energy use.
3Reliability
If the engine is started to provide lubrication for transmission elements, then transmission reliability is improved, but fuel consumption increases
Solution Approach 1:
The system performs preliminary assessment of transmission fluid temperature before deciding to start the engine for lubrication purposes. By checking the temperature in advance, the system can determine whether the transmission fluid has reached a temperature sufficient for adequate lubrication, and only starts the engine when necessary to achieve proper lubrication conditions, avoiding unnecessary fuel consumption.
Solution Approach 2:
The engine serves the transmission system by providing lubrication when the transmission fluid temperature is insufficient. The engine's operation naturally heats the transmission fluid through thermal coupling, allowing the transmission system to benefit from the engine's thermal output for its own lubrication needs without requiring a separate heating system.
4Temperature
If the engine is started for the first time since a vehicle drive start request, then both cabin heating and transmission lubrication needs are addressed, but system complexity increases
Solution Approach 1:
The engine serves multiple functions simultaneously - it provides both cabin heating through the heater core and transmission lubrication through fluid temperature elevation. By using the single engine start event to address both needs, the system avoids requiring separate heating systems and lubrication systems, thereby reducing overall system complexity while maintaining comprehensive temperature management.
Solution Approach 2:
The system merges the cabin heating function and transmission lubrication function into a single engine operation decision. Rather than independently controlling engine starts for heating purposes and lubrication purposes, the controller combines these functions and makes a unified start decision based on the aggregate needs of both systems, simplifying the control logic.
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
Ensures efficient engine starting for both heating the cabin and lubricating the transmission, enhancing passenger comfort and vehicle performance by optimizing energy use and maintaining powertrain health.
Implementation Method 1
an internal combustion engine typically consumes petroleum-based fuel most efficiently
Implementation Method 2
Starting of the engine can be controlled to generate heat for a cabin compartment in the HEV
Implementation Method 3
a transmission in the vehicle have sufficient lubrication before a torque is applied to the transmission
Data Source
AI summary
A system and method is provided for initiating starting of an engine in a hybrid electric vehicle (HEV) for a first time since a vehicle drive start request. Based on a predetermined fluid temperature and a powertrain fluid temperature from at least one of the powertrain elements in the HEV, it is determined whether energy from the engine is demanded. When the energy from the engine is demanded, the engine is started to provide energy for at least one of heating of a cabin compartment in the HEV and lubrication of a portion of powertrain elements in the HEV.