Hybrid Engine Throttle Control for Smooth Startup
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Solution Overview
Problem
Existing engine control systems for hybrid vehicles face issues with inconsistent torque output and air-fuel ratio variations during engine restarts, leading to undesirable vibrations and pollutant emissions, as the amount of air taken into the engine varies each time, which is not adequately addressed by existing technologies.
Innovation Solution
A control apparatus and method that includes a throttle valve drive unit and a start-up control unit, which limits the opening degree of the throttle valve and the rate of power increase to ensure consistent engine startup, using a start-up control unit that calculates a target opening degree based on required power and executes limiting control to prevent sudden power spikes, thereby maintaining a stable air-fuel ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the amount of air taken into the engine during restart is increased to ensure sufficient oxygen for combustion, then the engine can start more reliably, but the torque output becomes inconsistent and causes vibrations
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the throttle valve opening degree based on the detected in-cylinder pressure. The control unit modifies the air intake parameter (throttle opening) according to the actual pressure condition, ensuring consistent air-fuel ratio and torque output during engine restart while maintaining reliable starting across different pressure conditions
2Speed
If the throttle valve opens rapidly to provide sufficient air for engine startup, then the engine starts faster, but the air-fuel ratio varies and increases pollutant emissions
Solution Approach 1:
The patent implements feedback control by continuously detecting the in-cylinder pressure and using this information to adjust the throttle valve opening degree. The control unit receives feedback from the pressure sensor and modifies the air intake accordingly, maintaining a stable air-fuel ratio during startup and reducing pollutant emissions while ensuring fast engine startup
3Productivity
If the throttle valve opening degree is not limited during engine restart, then the air intake responds quickly to startup demands, but the rate of power increase becomes too high causing driver discomfort
Solution Approach 1:
The patent applies dynamics by making the throttle valve opening degree dynamic rather than fixed. The control unit adjusts the throttle opening in real-time based on in-cylinder pressure conditions, allowing the system to adapt between fast response and smooth power delivery. This dynamic control ensures quick air intake response while limiting the rate of power increase to maintain driver comfort during engine restart
Data Source
AI summary
An engine ECU (280) and an HV_ECU (320) control a throttle motor (296) such that the throttle valve opening degree (TH) does not exceed a prescribed limit (THlim) and a rate of increase (Ta/t) in the throttle valve opening degree is equal to or lower than a predetermined opening degree increase rate (Tb/t) for a predetermined time period after start-up of the engine (120) is initiated. Thus, power output from the engine is controlled so as not to increase significantly for the predetermined time period. Accordingly, while the engine starts up, a shock that can be felt by a driver can be suppressed. In addition, variation in the amount of air taken into the engine when the engine is started is also reduced, which reduces variation in the amount of pollutants in the exhaust gas emitted while the engine starts up.