Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02P—IGNITION, OTHER THAN COMPRESSION IGNITION, FOR INTERNAL-COMBUSTION ENGINES; TESTING OF IGNITION TIMING IN COMPRESSION-IGNITION ENGINES
  • F02P19/00—Incandescent ignition, e.g. during starting of internal combustion engines; Combination of incandescent and spark ignition
  • F02P19/02—Incandescent ignition, e.g. during starting of internal combustion engines; Combination of incandescent and spark ignition electric, e.g. layout of circuits of apparatus having glowing plugs
  • F02P19/025—Incandescent ignition, e.g. during starting of internal combustion engines; Combination of incandescent and spark ignition electric, e.g. layout of circuits of apparatus having glowing plugs with means for determining glow plug temperature or glow plug resistance
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D41/00—Electrical control of supply of combustible mixture or its constituents
  • F02D41/20—Output circuits, e.g. for controlling currents in command coils
  • F02D2041/202—Output circuits, e.g. for controlling currents in command coils characterised by the control of the circuit
  • F02D2041/2024—Output circuits, e.g. for controlling currents in command coils characterised by the control of the circuit the control switching a load after time-on and time-off pulses
  • F02D2041/2027—Control of the current by pulse width modulation or duty cycle control

Definitions

• This invention relates to the field of diesel engine cold start equipment, in particular to the field of control of glow plugs for diesel engine preheating.
• the problem to be solved is glow plug control, wherein the temperature of the glow tip is determined from the measured voltage between the electrode and the glow tube and the heating power supplied to the glow plug is adjusted based on the such determined temperature.
• the goal of the invention is to simplify the glow plug temperature regulation, to reduce temperature deviation from the target temperature and to preserve a simple construction of the glow plug or even to simplify it.
• the activity of glow plugs which enable fuel self-ignition in diesel engines while it is not warm enough, is in general determined by the glow plug controller.
• the glow plug controller can be a simple switch, which connects the glow plugs to the power supply when their operation is required and disconnects them when their operation is no longer required. In this case the glow plugs must be of self-regulating type.
• the glow plug temperature is affected by several factors. The supply voltage that determines the power supplied to the glow plugs can vary considerable. Also the glow plug cooling varies considerable in different engine operation regimes. None of the mentioned factors is compensated by the simplest glow plug controllers, therefore the glow plugs usually do not operate at the optimal temperature. If the plug temperature is too low, the conditions for fuel ignition at the right time are not satisfied.
• glow plug controllers regulate the supplied electric power. As many factors as possible that affect the glow tip temperature are considered for the regulation. Some important factors can be easily measured and compensated for directly by the controller, such as the variations in the supply voltage. But data about the engine operation regime must be obtained by the controller from other devices. This loads communication lines, complicates software and increases the possibility for failures. Besides, a lot of effort is necessary at the engine development stage to measure glow plug cooling at all relevant engine operation regimes.
• Patents JP59068569 and JP56066456 treat glow tip temperature measurement by thermal voltage measurement on a sensor embedded in the glow plug. These dedicated thermocouple sensors may measure the temperature precisely, but the solution is expensive due to the integration of an additional thermocouple in the glow tip and the corresponding electric feed wiring. These additional elements are not required in the present invention. Another advantage of the present invention is that it can be used on existing models and types of plugs.
• the main idea of the invention is a regulation of the supplied power, with regard to the measured thermal voltage between joints of different materials in the glow part of the plug, regardless of how the aforementioned thermal voltage is measured.
• the thermal voltage on the glow part of the plug is preferably measured by measuring the voltage between the electrode and the glow tube.
• the term "thermal voltage”, as used in this patent, is the voltage that appears in an electric circuit, which consists of conductors of different materials and where the joints between the conductors are on different temperatures.
• the measured thermal voltage is used, which appears predominantly on the glow part of the glow plug.
• the temperature of the glow tip is determined from the value of the thermal voltage. This temperature and the reference temperature is used by a controller to regulate the electric heating power. Pulse width modulation is preferably used for adjusting the electric heating power, wherein the current that heats the plug is alternately
• the time between pulses, when the switch is turned off, is taken advantage of to determine the voltage between the electrode and the glow tube.
• the average power the plug receives can be set by choosing the width of the pulses or their period. The required power is determined from the measured temperature and the given target temperature of the glow tip.
• the glow part 1 of the plug has a considerably higher temperature than the other parts. Therefore the thermal voltages on the joints between different metals in the glow part of the plug are much higher than all the other thermal voltage on other joints in the circuit that occurs when the voltage between the electrode 2 and the glow tube 3 is measured.
• the solution in accordance with the invention works equally well with any number of elements and joints in the plug.
• the joint 6 between the glow tube and the heating element 5, which is usually the heating coil, and the joint 8 between the heating element 5 and the electrode 2 of the plug always exist.
• the amplitude of the thermal voltage on a single joint depends on the temperature of the joint and on the composition of both materials. With a suitable selection of materials, it is achieved that the voltages on all joints do not cancel out.

Landscapes

• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Ignition Installations For Internal Combustion Engines (AREA)
• Control Of Resistance Heating (AREA)

Applications Claiming Priority (2)

Publications (1)

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Citations (3)

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• 2004
  • 2004-07-19 SI SI200400212A patent/SI21858A/sl not_active IP Right Cessation
• 2005
  • 2005-07-19 EP EP05759454A patent/EP1787022A1/de not_active Withdrawn
  • 2005-07-19 WO PCT/SI2005/000022 patent/WO2006009523A1/en active Application Filing

Patent Citations (3)

Non-Patent Citations (1)

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