Internal Combustion Engine Control Device for Low-Temperature Start
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Solution Overview
Problem
When an internal combustion engine is started at low temperatures, the friction torque and mechanical loss due to friction are increased by lowering the in-cylinder pressure during motoring, which degrades the startability of the engine.
Innovation Solution
An internal combustion engine control device and method that control the in-cylinder pressure during motoring by increasing it when the engine temperature is at or below a predetermined threshold, using a temperature acquisition unit, a motoring execution unit, and an in-cylinder pressure control unit to adjust the valve closing timing of the intake valve.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the in-cylinder pressure is lowered during motoring to promote rise in engine rotational speed, then the engine rotational speed increases faster, but the friction torque and mechanical loss due to friction increase
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the valve closing timing of the intake valve based on engine temperature. When the engine temperature is low, the valve closing timing is advanced to increase in-cylinder pressure, which reduces friction torque and mechanical loss. When the engine temperature is normal, the valve closing timing is retarded to lower in-cylinder pressure, which promotes faster rise in engine rotational speed. This parameter adjustment resolves the contradiction by selecting the optimal pressure level according to operating conditions.
2Power
If the valve closing timing of the intake valve is advanced to increase combustion energy at low temperatures, then the combustion energy increases, but the in-cylinder pressure during motoring increases which may reduce the rise in engine rotational speed
Solution Approach 1:
The patent applies dynamics by making the valve closing timing adjustable rather than fixed. The control device dynamically changes the valve closing timing based on real-time engine temperature detection. At low temperatures, the timing is advanced to maximize combustion energy. At normal temperatures, the timing is retarded to optimize rotational speed rise. This dynamic adjustment allows the system to adapt to different operating conditions and resolve the contradiction between combustion energy and rotational speed rise.
3Loss of energy
If the in-cylinder pressure is increased during motoring to reduce friction torque at low temperatures, then the mechanical loss due to friction decreases, but the motor torque required for starting increases
Solution Approach 1:
The patent resolves this contradiction through parameter changes in valve closing timing based on engine temperature. When the engine is cold, the valve closing timing is advanced to increase in-cylinder pressure, which reduces friction torque and mechanical loss. When the engine is warm, the valve closing timing is retarded to lower in-cylinder pressure, which reduces the motor torque required for starting. This temperature-dependent parameter adjustment allows the system to optimize for the relevant factor in each operating condition.
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
The solution reduces the motor torque required for starting the engine without degrading its startability, even at low temperatures, by optimizing the in-cylinder pressure control based on engine temperature.
Implementation Method 1
a motor and a battery. The motoring execution unit is configured to execute motoring of the internal combustion engine using the motor
Implementation Method 2
combustion of an air-fuel mixture is started after the engine rotational speed is raised to a predetermined starting rotational speed
Data Source
AI summary
An internal combustion engine control device includes: a temperature acquisition unit configured to acquire the temperature of an internal combustion engine at the time when it is requested to start the internal combustion engine; a motoring execution unit configured to execute motoring of the internal combustion engine using the motor when it is requested to start the internal combustion engine; and an in-cylinder pressure control unit configured to control the in-cylinder pressure of the internal combustion engine during the motoring based on the temperature of the internal combustion engine. The in-cylinder pressure control unit is configured to execute in-cylinder pressure increase control, in which the in-cylinder pressure is increased when the temperature of the internal combustion engine is equal to or less than a predetermined threshold temperature compared to when the temperature of the internal combustion engine is higher than the threshold temperature, since the motoring is started.