JPS6316114A - Heating device for engine oil - Google Patents

Abstract

PURPOSE:To enable a heater to stop automatically after heating engine oil to a pre-determined temperature without provision of any special control device, by installing a heater with a thermistor ceramic with a positive characteristic in the circulating system of the engine oil. CONSTITUTION:Between oil strainer 8 to suck the oil in an oil pan 7 and an oil pump 6, an oil heating device 10 is installed at the downstream of an oil filter 9. Said oil heating device 10 contains, in its housing 20, a stack comprising a heater 22 made of ceramic with a positive characteristic, heat discharging fins 23, plate electrodes 24, 25, and plate spring 26. As heating of oil advances for increasing the temperature of the oil, the electric resistance of said heater 22 increases until the current stops at determined temperature.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an engine oil heating device for an engine mounted on a vehicle.

[Prior Art] In a diesel engine vehicle, the viscosity of engine oil increases when the vehicle is cold, so that sufficient oil may not be supplied to the engine and downstream parts immediately after starting. In such a case, for example, the wear of the piston ring and the inner surface of the cylinder may progress excessively, resulting in problems such as reduced starting performance or failure to start at all.

As a countermeasure to this problem, wide-temperature engine oil (Multigrade Ura) is generally used, which has low viscosity and high fluidity even at low temperatures. However, this type of engine oil is mixed with various additives in order to obtain low viscosity characteristics at low temperatures, and some of these additives have the property of causing metal corrosion and carbon deposits in the piston ring grooves. There's something about it.

If a detergent dispersant is added to compensate for the inferiority of such additives, the cost will increase because the dispersant is expensive. Furthermore, this dispersant tends to change over time, and there is also the problem that the viscosity-temperature characteristics of engine oil are not stable.

For this reason, it is conceivable to install a heater in the engine oil circulation system to heat the engine oil to the optimum viscosity at the time of startup.

[Problems to be solved by the invention] However, when engine oil temperature rises,
There is no need to continue heating as the engine heats it while the engine is running.

For this reason, when using a well-known ordinary electric heater, special control means such as a temperature sensor or relay must be used in order to stop the heating operation when the engine oil reaches a predetermined temperature. Such control means (1
M construction is complicated and expensive.

[Means for Solving the Problems] The present invention aims to heat engine oil without using special control means, and uses PTC (PTC) as a heater.
A positive characteristic thermistor is characterized by the use of ceramic.

[Function] PTC ceramic has the characteristic of exhibiting a rapid change in resistance due to crystalline transition near the Curie point, and for this reason, PTC ceramic itself functions to control its own temperature. Therefore, since heating is automatically stopped once the engine oil is heated to a predetermined temperature, no special control means is required.

[Embodiment of the Invention] The present invention will be described below based on an illustrated embodiment.

FIG. 5 schematically shows a lubrication system configuration diagram of a vehicle equipped with a diesel engine, where 1 is a piston, 2 is a connecting rod, 3 is a crankshaft, 4 is an intake valve, and 5 is an exhaust valve.

An oil pump 6 attached to the crankshaft 3 distributes and supplies engine oil stored in an oil pan 7 to each lubricating location. That is, due to the operation of the oil pump 6, engine oil in the oil pan 7 passes through the oil strainer 8 and the oil filter 9 to the heating device 1 of the present invention.
0 and is pressurized by the oil pump 6, the oil passage in the crankshaft 3 is used to connect the connecting rod 2 and the crankshaft 3 to the connecting bearing, the cam surface of the camshaft 11, the timing gear 12, and other parts. Sliding member 13...
・Supplied to

The heating device [0 is shown in FIGS. 1 to 4, and 20
is the housing of the heating device IO. The housing 20 has an oil port 21 on one side and an oil outlet (not shown) on the other side. The engine oil that has passed through the oil filter 9 is introduced into the housing 20 through the oil port 21, heated within the snake housing 20, and then sucked into the oil pump 6 from the oil outlet.

Inside the housing 20, there are a heater 22, radiation fins 23,
. . , electrode plates 24, 25 and leaf springs 26 are housed in a stacked manner.

As shown in FIG. 4, the heater 22 is made of PTC (positive characteristic semiconductor thermistor) ceramic, and the PTC ceramic heater 22 is formed, for example, in the shape of a flat plate.

Both sides of this PTC ceramic heater 22 include nickel ohmic electrodes formed by electroless plating, and electrode surfaces 27.2 made of Ag and Pd with excellent corrosion resistance covering the electrodes.
8 is formed. The PTC ceramic heater 22 of this embodiment has Ba, Pb, and Ti as main components and has a Curie temperature of, for example, 150°C.

One electrode surface 2 of the PTC ceramic heater 22
7 is in contact with one of the electrode plates 24, and the other electrode surface 28 is joined to the fins 23.

The other electrode plate 25 is in contact with the other side of the fin 23 .

Further, other fins 23, 23 are laminated on the other side of each electrode plate 24, 25, respectively.

Although the fins 23 are corrugated fins, they may be plate fins.

The heater 22, fins 23, etc., which are laminated in this way
The electrode plates 24 and 25 are housed in the housing 2o and are held by being pressed by a leaf spring 26 from one side.

The operation in such a configuration will be explained.

When the electrode plates 24 and 25 are connected to a power source and a voltage is applied, the PTC ceramic heater 22 generates heat. This heat is
The temperature is transmitted to the corrugated fins 23, and the temperature of the surface of each fin is increased.

On the other hand, due to the operation of the oil pump 6, the engine oil in the oil pan 7 is transferred to the oil strainer 8 and the oil filter 9.
The engine oil flows from the oil port 21 of the housing 20 through the surface of the heater 22 and the gaps between the fins 23 to the outlet side.

At this time, the engine oil comes into contact with the surface of the heater 22 and the surfaces of the fins 23, which are 1 m high, and thus heat is transferred, so that the temperature rises.

The engine oil, which is heated to the optimum temperature when passing through the oil heating device 10, has a low viscosity, and is then passed through the oil pump 6 into the engine and into each lubricating system component 1.
It is distributed and supplied to 3... Therefore, by heating engine oil in cold weather and supplying it with a lower viscosity, it is possible to significantly improve engine startability, reduce horsepower loss by reducing worn horsepower, and improve fuel efficiency.

Moreover, the PTC ceramic heater 22 increases its own resistance value as the temperature rises, for example, 15
If the temperature is set at a single point of 0°C, when the ambient temperature, that is, the temperature of the engine oil, reaches around 150°C, the P
No current is passed through the TC ceramic heater 22 itself, and heat generation is automatically stopped.

Therefore, this heater 22 becomes a constant temperature heater, which is not only highly safe, but also requires no special temperature control means, resulting in a simple structure of the heating device 10 as a whole, which enables cost reduction.

FIG. 6 shows the characteristics when using the engine oil heating device 10 of the present invention, and the temperature change of the engine oil introduced into the oil pump 6 is maintained at 100° C., which is said to provide stable operation. While it takes about 10 minutes to start the engine in a conventional vehicle that is not equipped with an engine heater heating device, the vehicle according to the present invention reaches 100'C in about 2 minutes, which is faster than the conventional 115°C.
It can be seen that the time can be reduced.

Note that the leaf spring 26 has the function of absorbing thermal expansion and contraction of the fin 23 due to changes in 1H degree, as well as absorbing vibration and preventing damage.

The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the scope of the claims.

That is, for example, the PTC ceramic heater is not limited to a flat rectangular shape, but may be disc-shaped, ring-shaped, honeycomb-shaped, etc., and it is not limited to one PTC ceramic heater, but a plurality of PTC ceramic heaters may be used. .

Instead of the corrugated fins and plate fins described above, the fins may be in the shape of a comb or a protrusion, and their arrangement can also be varied in various ways, such as circular or spiral.

Of course, the shape of the housing may also be circular, spherical, etc.

Furthermore, the heating device 10 may be installed anywhere in the oil circulation system, such as inside the oil pan, between the oil pan and the oil filter, between the oil pump and the engine, etc.

[Effects of the Invention] As explained above, according to the present invention, engine oil is
Since it was heated using a TC ceramic heater,
When starting the engine in cold weather, the temperature of the engine oil can be raised within a short time to close to the Curie temperature set in the heater, and low viscosity can be achieved. Moreover, since the PTC ceramic heater automatically stops generating heat when it reaches around the one Curie point, it has high thermal safety and reliability, and does not require any special temperature control means, making the structure simple.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, in which Fig. 1 is a perspective view showing the appearance of an oil heating device, Fig. 2 is a sectional view, Fig. 3 is a perspective view of internal components, and Fig. 4 is a PTC ceramic heater. FIG. 5 is a configuration diagram showing the lubrication system of the engine, and FIG. 6 is a characteristic diagram. DESCRIPTION OF SYMBOLS 1... Piston, 6... Oil pump, 7... Oil pan, 8... Oil strainer, 9... Oil filter, 10... Oil heating device, 2o... Housing, 21... ...Oil inlet, ...PTC ceramic heater, 23...Fin, 24.25...Electrode plate, 2B...Temporary spring. Figure 1 Figure 2 Figure 3 Figure 4

Claims (2)

[Claims] (1) An engine oil heating device that heats the engine oil by providing a heater in the middle of the engine oil circulation system, characterized in that a PTC (positive characteristic thermistor) ceramic is used as the heater. (2) An engine oil heating device according to claim (1), characterized in that heat dissipating fins are bonded to the PTC ceramic in a heat conductive manner, and engine oil is passed between the fins to heat the engine oil. .