Hybrid Engine Start Control With Speed-Threshold Cranking
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Hybrid vehicles face engine stall issues due to decreased rotational speed of internal combustion engines before air introduction, which existing technologies fail to prevent effectively.
Innovation Solution
A control device for hybrid vehicles that includes a first start control unit for cranking the engine, a second start control unit for starting the engine without cranking, and a setting unit to set a rotational speed threshold based on vehicle speed, allowing the engine to be started by cranking when the speed is below the threshold and without cranking when it is above, using an ECU to manage the throttle valve and hydraulic pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the engine is started by cranking when rotational speed is low, then the engine can be reliably started, but the system complexity increases due to requiring multiple start control modes
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the rotational speed threshold based on vehicle speed. When vehicle speed is high (≥5 km/h), the threshold is set to 50 rpm; when vehicle speed is low (<5 km/h), the threshold is set to 100 rpm. This adaptive parameter adjustment allows the system to maintain reliable engine starting across different operating conditions while using a unified control framework, thereby resolving the contradiction between reliability and system complexity.
2Speed
If air introduction is delayed, then the engine rotational speed decreases, but engine stall occurs before combustion can begin
Solution Approach 1:
The patent applies preliminary action by pre-opening the throttle valve before engine start is initiated. When a start request is detected, the throttle valve is opened in advance to ensure air is already present in the engine when combustion begins. This preliminary air introduction prevents engine stall caused by rotational speed decrease during the air introduction period, thereby resolving the contradiction between maintaining rotational speed and ensuring operational stability.
3Speed
If the throttle valve remains closed during engine start, then air introduction is delayed, but engine stall is prevented by maintaining higher rotational speed
Solution Approach 1:
The patent applies preliminary action by pre-opening the throttle valve before engine start is initiated. When a start request is detected, the throttle valve is opened in advance to ensure air is already present in the engine when combustion begins. This preliminary air introduction prevents engine stall caused by rotational speed decrease during the air introduction period, thereby resolving the contradiction between maintaining rotational speed and ensuring operational stability.
Solution Approach 2:
The patent applies dynamics by making the throttle valve opening state dynamic rather than fixed. The throttle valve opening is controlled based on real-time detection of start requests and vehicle speed conditions. This dynamic control allows the system to optimize both rotational speed maintenance and air introduction timing, resolving the contradiction between speed and combustion reliability.
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
Prevents engine stall by ensuring timely air introduction and efficient starting of the internal combustion engine, either through cranking or without cranking, based on the rotational speed and vehicle speed thresholds, thereby ensuring reliable engine operation.
Implementation Method 1
a motor in a power transmission path between the engine and a wheel
Implementation Method 2
The internal combustion engine may be started by supplying and burning fuel without cranking
Data Source
AI summary
A control device for a hybrid vehicle that includes an internal combustion engine, a motor, and a clutch provided between the internal combustion engine and the motor includes a first start control unit that starts the internal combustion engine by causing the motor to perform cranking, a second start control unit that starts the internal combustion engine without causing the motor to perform cranking, and a setting unit that sets a threshold for a rotational speed of the internal combustion engine according to a vehicle speed of the hybrid vehicle. When the rotational speed of the internal combustion engine is less than the threshold, the first start control unit starts the internal combustion engine. When the rotational speed of the internal combustion engine is equal to or higher than the threshold, the second start control unit starts the internal combustion engine.