Glow Plug Heater Temperature Matching via Cable Resistance
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Solution Overview
Problem
Internal combustion engines with combustion pressure sensor incorporated glow plugs and sensor nonincorporated glow plugs experience differences in heater energization characteristics, leading to varying heater temperatures when the same voltage is applied, affecting start-up assistance across cylinders.
Innovation Solution
The engine design features a combustion pressure sensor incorporated glow plug with a first heater and pressure sensor in some cylinders and a sensor nonincorporated glow plug with a second heater in others, with specific electricity supply cable configurations to match heater temperatures by adjusting the resistance of the electricity supply lines and conductive members, ensuring closer energization characteristics between the two types of glow plugs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the same voltage is applied to both combustion pressure sensor incorporated glow plugs and sensor nonincorporated glow plugs, then the control system is simple, but the heater temperatures differ due to structural differences
Solution Approach 1:
The patent applies different resistance values to different electricity supply lines based on their destination. Specifically, the electricity supply line connected to the sensor nonincorporated glow plug has a higher resistance than the line connected to the sensor incorporated glow plug. This local differentiation in electrical resistance compensates for the structural differences between the two glow plug types, ensuring that both heaters reach the same temperature when the ECU applies the same control signal.
2Temperature
If the resistance of the second electricity supply line is increased, then the heater temperature of sensor nonincorporated glow plug matches the sensor incorporated glow plug, but the electrical characteristics of the circuit change
Solution Approach 1:
The patent modifies the electrical resistance parameter of the electricity supply lines to achieve temperature matching. By carefully selecting and setting the resistance values - specifically making the resistance of the second electricity supply line (connected to sensor nonincorporated glow plug) higher than that of the first electricity supply line (connected to sensor incorporated glow plug) - the system compensates for the inherent structural differences between the two glow plug types. This parameter adjustment ensures that both heaters reach equivalent temperatures under the same control conditions.
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 configuration ensures that the same effective voltage applied to all cylinders results in minimized differences in heater temperature across the engine, improving the uniformity of glow plug action and start-up assistance.
Implementation Method 1
a first heater which generates heat through energization
Implementation Method 2
a second heater which generates heat through energization
Implementation Method 3
a pressure sensor for detecting combustion pressure of the cylinder(s) to which the combustion pressure sensor incorporated glow plug is mounted
Data Source
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AI summary
[Objective] To provide an internal combustion engine in which, when the same effective voltage is applied to cables and glow plugs attached to the engine, the occurrence of a difference in heater temperature among cylinders is restrained. [Means for Solution] In an internal combustion engine 1 which includes a combustion pressure sensor incorporated glow plug 20A and sensor nonincorporated glow plugs 20B, a first plug regression line Lp1 and the second plug regression line Lp2 are in such a relation that, at any temperature Tx within the temperature range Tr, a second voltage Vp2x is lower than a first voltage Vp1x; the resistance RB2a of a second electricity supply line 310B is greater than the resistance RB1a of a first electricity supply line 310A; and a first section regression line Lc1 and a second section regression line Lc2 are in such a relation that, at any temperature Tx within the temperature range Tr, an overall voltage deviation |vc1x - Vc2x|, which is the absolute value of the difference between a third voltage Vc1x and a fourth voltage Vc2x, is smaller than a first-second plug voltage difference (Vp1x - Vp2x).