JPH09303125A - Oil heater with temperature adjustment concurrently serving as oil level meter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To fixedly hold a temperature of engine oil and prevent decreasing of power of an engine with very small power consumption even in a very cold district, by mounting a mark and a stopper in a bar having flexiblity to serve as an oil level meter, and burying a heating unit and a heat sensing element in the inside of this oil level meter. SOLUTION: A mark 7 is mounted in a bar 4 formed by providing a stopper 5 to serve as an oil level meter, in the inside thereof, a heating unit 1 and a heat sensing element 2 are buried. The heating unit 1 and the heat sensing element 2 are connected by a lead, a control circuit 3 comprising a voltage comparator and an output transistor is buried in a stopper part or in the vicinity thereof of the oil level meter. In accordance with a temperature of engine oil, internal resistance of the heat sensing element 2 is determined, in accordance with changing of the temperature of oil, a current flowing in the heat sensing element 2 is changed, so as to take out this current changing by a voltage change, when voltage in both ends of the heat sensing element 2 is decreased lower then specified voltage, a current flowing in the heating unit 1 is controlled to be stopped.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oil heating apparatus with an oil temperature control circuit, which also serves as an oil level meter, and which prevents engine oil from becoming inoperable due to its viscosity increasing in cold regions. .

[0002]

2. Description of the Related Art In cold climates, for example, when the engine oil mounted on an automobile falls below about -20 ° C., the engine may not be started or may be difficult to start. This is because the viscosity of the engine oil becomes high, but as a measure to prevent the deterioration of the performance of this engine, it is necessary to heat the engine oil by heating it from the outside,
Even if it could be started, there was no effective means other than warming up for a long time until the engine functioned normally.

[0003]

However, these measures are not drastic measures to prevent the deterioration of the engine performance, and therefore, in extreme cold regions where the temperature is -20 ° C or -30 ° C, for example. The measures are not very useful. Therefore, in such a case, it is considered that the engine oil is actively heated to prevent the temperature of the oil from lowering.

As this method, generally, a resistance heating wire such as Ni-Cr or Fe-Ni-Cr or a heating resistor such as an alloy film thereof is energized to prevent a temperature drop due to the generated heat. Conceivable. However, in this case, there is a drawback that the power consumption is extremely large. In the case of engine oil for automobiles, the electric power of the battery has to be used for heating the oil, so it is necessary to suppress the electric power for heating as much as possible.

According to the present invention, when the engine oil is heated in order to prevent it from lowering in temperature, the power consumption is extremely low, the volume occupied by the device is hardly required, and the temperature of the oil is maintained at a constant temperature. An object of the present invention is to provide an oil heating device that can also be used as an oil level meter.

[0006]

According to the present invention, a control circuit, which is embedded in an oil level meter and includes a heating element powered by an automobile battery, a heat sensitive element, and the like, is installed.

The internal resistance of the heat-sensitive element embedded in the oil level meter is determined by the temperature of the engine oil, and the current flowing through the heat-sensitive element is changed according to the temperature change of the oil. The change in the current is taken out as a voltage change, and when the voltage across the heat-sensitive element falls below (or rises above) a specified voltage, the current flowing through the heating element is stopped.

When the voltage across the heat-sensitive element rises (or falls) above the specified voltage, current is again supplied to the heating element to heat the engine oil.

When a PTC heating element is used as the heating element, the amount of heat generated per volume is larger than that of other various heating elements, so that it is large to be incorporated in an oil level meter whose size is limited. There are advantages.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION According to the present invention, an oil level meter having a bendable and flexible rod provided with a stopper having an enlarged diameter at one end is provided with marks indicating the upper and lower limits of the oil amount. And A PTC heating element or the like (not limited to a PTC heating element) as a heating element inside the level meter, and an NTC thermistor or PTC as a heat sensitive element.
Select either thermistor (positor) to embed.

Further, the heating element and the heat-sensitive element are connected by a lead as a part of the constituent elements, and a control circuit composed of a voltage comparator and an output transistor is embedded in the stopper portion of the oil level meter or in the vicinity thereof. Alternatively, the control circuit may have a structure attached to the outside of the level meter. From the control circuit, two positive and negative cables for power supply are pulled out from the end of the bar serving as the level meter having the stopper, and are connected to both positive and negative terminals of the battery.

A transparent tube may be used for the flexible rod, and a mark may be attached to the buried object to indicate the upper and lower limits of the amount of oil to seal both ends.

As shown in the control circuit diagram of FIG. 2, the thermosensitive element and the fixed resistor (R1) in the control circuit are connected in series,
When the voltage of the battery is applied from both ends, the voltage generated across the thermosensitive element changes depending on the internal temperature of the level meter.

The voltage generated in the heat sensitive element is taken out,
It is used as one input of the voltage comparator (A) in the control circuit. The other input of the voltage comparator receives the specified voltage divided from the battery.

The output of the voltage comparator is passed through a forward diode (D) for the purpose of raising the threshold value (or a protection resistor for limiting the base current may be inserted in series with the diode if necessary). One end of a heating element that is connected to the base of the output transistor and serves as a load is connected to the emitter or collector of the output transistor, and the other end is connected to the negative or positive electrode of the battery. The output transistor is NP
Either N type or PNP type may be used.

The automobile battery includes a 12V battery for a passenger car and a 24V battery for a truck, but either battery may be used in the present invention. Further, the present invention is not limited to automobile batteries.

[0017]

EXAMPLE An oil level meter for embedding an oil heating device according to the present invention as shown in FIG. 1 was prepared. The oil level gauge has a flexible Teflon tube with an outer diameter of 8 mm that can withstand a high temperature of 200 ° C and can be inserted into a curved oil level tube. .

A PTC heating element as a heating element in the tube,
An NTC thermistor as a heat sensitive element and a control circuit including a voltage comparator and an output transistor as a part of the constituent elements were inserted, and two power cables were pulled out from the circuit to seal both ends of the tube. Next, a ring having an outer diameter of 12 mm was fitted to the end of the tube on the cable side to serve as a stopper. The Curie temperature of the PTC heating element was 230 ° C., and the power source was a 12V automobile battery.

FIG. 2 shows an embodiment of a control circuit diagram. With R2 = R3 = 20KΩ and R4 = R5 = 100KΩ, the resistance of the NTC thermistor at 25 ° C. is 5KΩ.
(B = 3600 ° K), two PTC heating elements having a resistance of 90Ω at 25 ° C were used in parallel.

In Table 1, 4 liters of engine oil was placed in a constant temperature bath of -30 ° C., the oil heating device according to the present invention was inserted, and a steady state was obtained when the resistance value of R1 was changed. The oil temperature and the average power consumption were measured and shown.

[0021]

[Table 1]

When the same PTC heating element as in the above example was used and 4 liters of engine oil in a constant temperature bath at -30 ° C was continuously energized and heated, -6 ° C
Then, the steady state was reached, and the power consumption was 7W.

[0023]

As described above, according to the present invention, since it is an oil heating apparatus with a temperature control in which an oil level meter has a heating element and a control circuit built-in, a volume occupied by the apparatus is hardly required. It is possible to provide an oil heating device that also serves as an oil level meter that can keep the temperature of engine oil constant with extremely low power consumption even in an extremely cold region where the outside air temperature is −20 to −30 ° C. and can prevent deterioration of engine performance. It is a thing.

[Brief description of drawings]

FIG. 1 is a structural diagram (partial cross-sectional view) of an oil level meter incorporating an oil heating device according to the present invention. However, the mark indicating the upper limit of the oil amount is omitted for the sake of space.

FIG. 2 shows an embodiment of a control circuit diagram of an oil heating apparatus according to the present invention.

[Explanation of symbols]

 1 heating element 2 heat sensitive element 3 control circuit section 4 level meter jacket 5 level meter stopper 6 power cable 7 oil level lower limit mark R1, R2, R3, R4, R5 fixed resistance TH NTC thermistor A voltage comparator D diode Q output transistor PTC PTC heating element B battery

Claims (2)

[Claims] 1. An oil level meter is provided by attaching a mark and a stopper to a flexible rod, and a heating element and a heat sensitive element are embedded in the oil level meter to detect a change in current flowing through the heat sensitive element. An oil heating device with a temperature control, which is also used as an oil level meter, provided with a circuit for controlling the heat generation amount of the heating element. 2. A Teflon tube is used for the flexible rod, a PTC heating element is used for the heating element, and N is used for the heat-sensitive element.
The oil heating device with temperature control, which also serves as an oil level meter according to claim 1, characterized in that a TC thermistor or a PTC thermistor is used.