Engine Intake Filling Control for Cold-Start Cylinder Head Distortion
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Solution Overview
Problem
Conventional engine coolers fail to effectively suppress significant thermal distortion caused by large temperature differences, particularly in the cylinder head, especially during engine start in extremely cold conditions, due to inadequate initial cooling and temperature uniformity.
Innovation Solution
A control apparatus that adjusts intake air filling amount based on the temperature of the cylinder head and lubricating oil, using a control unit to set an upper limit value for the intake air filling amount, thereby controlling the engine's output to prevent excessive temperature differences and distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the cooling water flow rate is increased to suppress thermal distortion, then the temperature difference is reduced, but the cooling water cannot flow through the engine immediately after start when the thermostat valve is closed
Solution Approach 1:
The control unit limits the intake air filling amount before the thermostat valve opens, preventing excessive temperature rise in the exhaust port area during the period when cooling water cannot flow. This preliminary restriction of heat generation avoids the need for immediate cooling that cannot be provided.
Solution Approach 2:
By restricting the intake air filling amount, the system preemptively counteracts the potential for excessive temperature difference that would occur if full power were applied in cold conditions. This prevents the harmful thermal distortion before it can develop.
2Reliability
If the thermostat valve is opened early to improve cooling, then cooling water flows immediately, but the temperature of cooling water reaches 100°C and no further cooling effect is expected
Solution Approach 1:
The control unit continuously monitors the temperature of the upper end of the cylinder head and adjusts the intake air filling amount accordingly. When the temperature exceeds the predetermined value, the control unit restricts the intake air filling amount to prevent excessive temperature rise, creating a feedback control loop.
3Temperature
If the intake air filling amount is restricted to suppress distortion, then temperature difference is reduced, but engine output is limited
Solution Approach 1:
The control unit dynamically adjusts the intake air filling amount limit based on real-time temperature feedback from the upper end of the cylinder head. As the engine warms up and temperatures stabilize, the restriction is gradually relaxed, allowing the engine to operate at full output once thermal equilibrium is achieved.
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
Effectively suppresses thermal distortion in the engine cylinder head by managing temperature differences through controlled intake air filling, ensuring the engine operates without excessive limitations on output.
Implementation Method 1
a measurement unit for outputting a measurement signal related to a temperature of an upper end of a cylinder head
Implementation Method 2
thermal distortion that occurs to the engine is caused by a temperature difference between a high-temperature portion having a high temperature and a low-temperature portion having a low temperature. A large temperature difference makes a deformation amount of the engine non-uniform
Data Source
AI summary
A control system for an engine includes: a valve that adjusts an intake air filling amount for a cylinder according to an operation amount of an accelerator pedal; a sensor that outputs a measurement signal related to a temperature of an upper end of a cylinder head having an intake port and an exhaust port communicating with the cylinder; and a control circuit that sets an upper limit value of the intake air filling amount to be smaller as the temperature of the upper end of the cylinder head is reduced base on the measurement signal at the start of an engine, and outputs, to the valve, a control signal corresponding to the operation amount of the accelerator pedal within a range where the intake air filling amount does not exceed the upper limit value.