Hybrid Engine Standby Control for Lean Combustion Stability
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Solution Overview
Problem
In hybrid vehicles, the standby operation of internal combustion engines during lean combustion can lead to unstable combustion and adverse exhaust performance due to reduced engine load and speed, which affects power output and fuel efficiency, especially when the battery State Of Charge (SOC) is high, causing overcharging and inefficiencies.
Innovation Solution
The internal combustion engine operates at a predetermined lean combustion region with a collector pressure higher than a threshold value, reducing engine power output and speed to prevent overcharging while ensuring combustion stability by controlling intake air throttling and supercharging, thereby maintaining efficient energy supply to the driving motor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the power output of the internal combustion engine is reduced during standby operation to prevent battery overcharging, then the battery overcharging is suppressed, but the combustion becomes unstable and exhaust performance deteriorates
Solution Approach 1:
The patent changes the operating parameters of the internal combustion engine by maintaining a higher engine speed during standby operation than conventional approaches. Specifically, the engine speed is controlled to be in a range of 1500-3000 rpm during standby, which is higher than the conventional low-speed operation. This parameter change allows the engine to maintain stable combustion and good exhaust performance while still preventing battery overcharging through reduced power output control.
2Reliability
If the engine load is reduced during standby operation, then the battery charging is controlled, but the in-cylinder gas flow motion is adversely affected and combustion stability deteriorates
Solution Approach 1:
The patent changes the engine operating parameters by maintaining a higher engine speed range (1500-3000 rpm) during standby operation compared to conventional low-speed operation. This parameter adjustment ensures that the engine maintains stable combustion characteristics and proper in-cylinder gas flow motion while still achieving battery charging control through reduced power output. The higher speed operation prevents the adverse effects on gas flow motion that would occur with excessive load reduction.
3Reliability
If the engine speed is reduced during standby operation, then the power output is reduced to prevent overcharging, but the combustion stability and exhaust performance are adversely affected
Solution Approach 1:
The patent changes the engine speed parameter to operate in a higher range (1500-3000 rpm) during standby operation compared to conventional low-speed operation. This parameter change maintains stable combustion and good exhaust performance while still preventing battery overcharging. The control system adjusts the power output within this speed range to achieve the desired charging control without compromising exhaust performance.
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 enhances acceleration response, ensures combustion stability, suppresses overcharging, and reduces noise and vibration, improving fuel efficiency and driving performance by optimizing engine operating points during standby operations.
Implementation Method 1
the standby operation employs the operation region where lean combustion is performed
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
In the present invention, an internal combustion engine (7) drives a generator (6). The internal combustion engine (7) carries out a standby operation. The standby operation is an operation involving assisting power supply to a drive motor (2). During the standby operation of the internal combustion engine (7), the SoC of a battery (4) is equal to or higher than a predetermined SoC threshold. The operating point of the internal combustion engine (7) during the standby operation is further on a lower-output side than the operating point of the same during the charging of the battery (4). The operating point of the internal combustion engine (7) during the standby operation is an operating point in which the collector pressure of the internal combustion engine (7) is equal to or higher than a predetermined collector pressure threshold. The operating point of the internal combustion engine (7) during the standby operation is within a lean combustion region.