Hybrid Vehicle Control System Anticipating Boost Locations
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Solution Overview
Problem
Hybrid electric vehicles experience undesirable noise, vibration, and harshness (NVH) and drivability issues due to sudden transitions from electric vehicle (EV) mode to parallel mode, and excessive component wear from sudden torque demands when the engine is switched on to meet driver demands.
Innovation Solution
A control system that allows drivers to set a target vehicle speed and automatically starts the engine before a boost location is reached, enabling the engine to provide additional power in boost mode, reducing the need for sudden torque transitions and maintaining EV mode without significant speed drops, thereby minimizing NVH and improving drivability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the engine is switched on automatically to meet driver torque demand in EV mode, then the torque demand is satisfied, but noise, vibration and harshness (NVH) increase and drivability is adversely affected
Solution Approach 1:
The control system predicts upcoming steep gradients using navigation data and topographical information, and proactively starts the engine before the vehicle actually needs the additional power. This preliminary action allows the engine to warm up and reach optimal operating conditions before being engaged, avoiding sudden engine startup NVH events when the driver is on the hill and would notice the disturbance.
2Power
If the engine is switched on automatically to meet driver torque demand, then the torque demand is satisfied, but component wear such as engine and clutch wear increases
Solution Approach 1:
The system anticipates steep gradients ahead using predicted route information and starts the engine in advance, allowing gradual engagement of the engine and clutch components. This prevents sudden high-torque demands on cold components, reducing thermal shock and mechanical stress that would otherwise accelerate wear.
3Power
If the powertrain transitions from EV mode to parallel mode, then additional power is available, but the transition time adversely affects drivability
Solution Approach 1:
The control system uses predicted gradient information from navigation data to start the engine before the vehicle reaches the steep section. This ensures the engine is already running and can be smoothly integrated into the powertrain without the delay of cold startup, eliminating noticeable power gaps during critical climbing moments.
Solution Approach 2:
The system continuously monitors actual vehicle performance against predicted requirements and adjusts engine timing and power delivery to maintain optimal performance throughout the gradient transition, ensuring smooth power delivery during mode changes.
Data Source
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AI summary
The invention relates to a control system for a hybrid electric vehicle (100), the vehicle having a powertrain (135) comprising at least one electric propulsion motor (123) and at least one engine (121), the control system being operable to control the vehicle to operate in an electric vehicle (EV) mode in which the at least one engine remains switched off and the at least one electric propulsion motor is configured to deliver drive torque and a boost mode in which the at least one engine is switched on to provide additional power to drive the vehicle. When the vehicle is operating in EV mode the system is further operable to determine whether a boost location exists ahead of the vehicle being a location at which a gradient of a driving surface is sufficiently high to require selection of the boost mode, the control system being operable automatically to command starting of the at least one engine before the boost location is reached.