WO2017021086A1

WO2017021086A1 - Method and device for the treatment of lubricant for an internal combustion engine

Info

Publication number: WO2017021086A1
Application number: PCT/EP2016/065893
Authority: WO
Inventors: Gerhard Haft; Rainer Hild; Rainer List; Wolfgang Mai
Original assignee: Continental Automotive Gmbh
Priority date: 2015-07-31
Filing date: 2016-07-06
Publication date: 2017-02-09
Also published as: DE102015214632B3

Abstract

A method and a corresponding device are proposed for the treatment of liquid lubricant (6) which comprises evaporable contaminants and which is situated in a crankcase (32) of an internal combustion engine (1). A partial mass flow of the lubricant (6) is branched off downstream of a lubricant pump (7) which circulates the lubricant (6) in a closed circuit, and said partial mass flow is fed via a counterflow heat exchanger (8) to a heating device (11). By way of the heating device (11), the lubricant (6) is heated to a temperature at which the contaminants change into the vaporous state. The mixture of lubricant (6) and vaporous contaminants is supplied to a vapour separation device (10), and the vaporous contaminants that are separated by the vapour separation device (10) are supplied to the intake air of the internal combustion engine (1), and the purified lubricant (6) is conducted from the vapour separation device (10) via the counterflow heat exchanger (8) back into the crankcase (32) of the internal combustion engine (1). As a heating device, an electric heating device or an exhaust-gas/lubricant heat exchanger (11) is provided.

Description

description

Method and device for preparing lubricant for an internal combustion engine

The invention relates to a method and an apparatus for processing lubricant containing vaporizable impurities for an internal combustion engine. Today's Otto internal combustion engines have a comprehensive lubrication system, usually in the form of pressure circulation lubrication, in which a pump from a reservoir, usually from the oil pan as part of the crankcase, which serves as a lubricant engine oil through a system of lines and channels to the consumers from where it flows without pressure back into the sump.

However, the lubricating properties of engine oil are worsened by the introduction of other substances such as fuel and water. This entry leads to an oil dilution, which increases the wear and the probability of the occurrence of a defect and reduces the life expectancy of the internal combustion engine. The contamination of the engine oil by these substances arises, on the one hand, that mixes fuel on the wall of the liner of the cylinder with the oil film located there and is then stripped in the engine oil and on the other hand, because water along with the combustion gases, which at the Blow piston rings past (blowby), get into the crankcase.

Especially with frequent cold starts of the internal combustion engine (for example: at -10 ° C) without subsequent warm-up (oil temperature <25 ° C), there is a risk that increase the proportions of fuel and water in the engine oil. This is due to the boiling behavior of these substances.

At ambient pressure, the boiling range of petrol starts at 25 ° C and the boiling point of water is 100 ° C. In extreme cases, this fuel-water content can lead to reduced lubrication of the internal combustion engine and mechanical damage due to increased friction. In addition, it may happen in a warm-up with initially very high proportion of fuel in the engine oil through the outgassing of the fuel that the internal combustion engine can not be operated safely. Due to the additional amount of fuel from the engine oil, which passes through the crankcase ventilation in the intake manifold, there is an over-enrichment of the combustion mixture, which can lead to combustion misfires despite reduced injection quantity. In overrun fuel cut-off operation (no injected fuel quantity), the internal combustion engine nevertheless generates a torque, which is generated exclusively via the combustion of the fuel vapor from the crankcase ventilation. These problems are increasingly in internal combustion engines, which are generally designed for a low engine oil temperature and / or operated with ethanol-containing fuels (especially E85 / E100) and / or used as a hybrid with a short-range electric motor (mixture enrichment in cold combustion engine).

The invention has for its object to provide a method and an apparatus can be processed with or with the contaminated lubricant of an internal combustion engine.

This object is solved by the subject matters of the independent claims. Preferred developments are specified in the dependent claims from ^¬.

The invention is characterized by a method and a corresponding device for processing vaporizable impurities containing, in a crankcase of a Internal combustion engine located, liquid lubricant. A partial mass flow of the lubricant is branched off downstream of a lubricant circulating in a closed loop lubricant pump and a

Countercurrent heat exchanger fed to a heater.

By means of the heater, the lubricant is heated to a temperature at which the impurities go into the vapor state. The mixture of lubricant and vapor impurities is supplied to a vapor separator, and the vapor impurities separated from the vapor separator are supplied to the intake air of the internal combustion engine, and the purified lubricant is passed from the vapor separator via the countercurrent heat exchanger back into the crankcase of the internal combustion engine.

By actively assisting the discharge by means of a heater and then separating the vaporized contaminants from substances incorporated in the lubricant such as fuel and water, the quality, in particular the lubricating properties of the lubricant can be maintained and wear, or the probability of a defect in moving parts of the internal combustion engine be minimized.

Furthermore, a larger number of cold starts without subsequent warm-up of the internal combustion engine possible, without causing the above problems, in particular not to shortened lubricant change intervals. The active support of the discharge has a positive effect on the life expectancy of the engine and result ^¬ damage due to altered or diluted lubricant can be prevented.

By using a countercurrent heat exchanger in the

Lubricant circulation, the lubricant in the inlet to the heating direction by that of the Dampfabscheidevorrichtung back flowing, hot lubricants are already preheated, so that the heating power for the heater is reduced.

According to an advantageous embodiment of the invention, an electrical heating device is used as a heating device, which is fed from the electrical system of the ^¬ driven by the internal combustion engine vehicle. The electric heater ^¬ direction may be formed, for example in the form of a heating coil of resistance wire to a piece of pipe, within which the lubricant is transported by means of the lubricant pump. In particular, the use of such an electric heater for vehicles is advantageous, which have an increased on-board voltage, such as a hybrid vehicle with an on-board voltage of 48 volts, which significantly reduces the power consumption of the electric heating element over conventional electrical systems.

Another advantage is that a continuous discharge already takes place in the warm-up phase of the internal combustion engine and can accumulate not so much fuel and water in the lubricant, especially in short-haul driving.

According to a further advantageous embodiment serves as a heater for the lubricant, an exhaust gas lubricant heat exchanger, which is connected via an exhaust gas inlet and an exhaust gas outlet with an exhaust line at a point upstream of an exhaust gas catalyst of the internal combustion engine. Since the exhaust gas is branched off upstream of the catalytic converter, exhaust gas with a high temperature is used

Available and there is a very effective heating of the lubricant.

The use of a heating device downstream Dampfabscheidevorrichtung results in a simple way to free the heated lubricant from the impurities now present in vapor form and feed back to the combustion. Further advantages and developments of the present invention will be explained in more detail with reference to the description of two embodiments with the aid of the schematic drawings. Show it :

1 shows an internal combustion engine with a device for the preparation of the lubricant according to a first embodiment,

2 shows an internal combustion engine with a device for the preparation of the lubricant according to a second embodiment and

Figure 3 is a diagram showing different courses for the

Fuel mass flow from the lubricant into the

Suction tube of the internal combustion engine shows.

It should be noted that features or components of different embodiments, which are the same or at least functionally identical to the corresponding features or components of the embodiment, are provided with the same reference numerals. In order to avoid unnecessary repetitions, features or components already explained on the basis of a previously described embodiment will not be explained in detail later.

An internal combustion engine 1 shown in FIG. 1 comprises an intake tract 2, an engine block 3, a cylinder head 4 and an exhaust tract 5. The intake tract 2 comprises i.a. a

Throttle 21 and a suction pipe 22 which is guided toward a cylinder 31 in the engine block 3.

The cylinder head 4 includes a valve train with a gas ^¬ inlet valve 41 and a gas outlet 42 and associated valve actuators 43, 44. The cylinder head 4 further comprises an injection valve 45 and a spark plug 46. Alternatively, the injection valve may be 45 arranged in the intake tract. 2 The engine block 3 includes a crankcase 32 which accommodates a cure ^¬ belwelle 33 and also a connecting rod 34 which is coupled to a piston 35 of the cylinder 31 and so couples the crankshaft 33 to the piston 35 of the cylinder 31st The crankcase 32 is also partially filled with lubricant 6, in particular engine oil and is circulated by means of a lubricating ^¬ medium pump 7 in a closed circuit. For this purpose, the suction side of the lubricant pump 7 is connected by means of a suction line 71 with the lowest point of a part of the crankcase 32 forming sump 36. A connected to the pressure side of the lubricant pump 7 main ^¬ lubricant line 72 leads to the cylinder head 4, so that in particular the mechanism of the valve gear of the gas inlet valve ^¬ 41 and the gas outlet valve 42 is supplied with lubricant 6. The lubricant system may also have other lubricant lines and riser channels leading to different, also to be lubricated, moving parts. Only a single cylinder 31 is shown, but the internal combustion engine 1 can also have a plurality of cylinders, the lubricant pump 7 ensuring lubrication for all parts of the individual cylinders to be lubricated. Moreover, neither a filter serving to separate solids contained in the lubricant 6 nor a crankcase ventilation device is shown in the figures. In addition, for reasons of clarity, the lubricant pump 7 is shown outside the crankcase 32. This is usually within the crankcase 32 is arranged ^¬ .

For controlling and / or regulating the internal combustion engine 1, an electronic control unit (ECU, electronic control unit) 15 is provided. The control device 15 contains a computing unit (processor) 16, which is coupled to a program memory 17 and a value memory 18 (data memory). The arithmetic unit 16, the program memory 17 and the value memory 18 may each comprise one or more microelectronic components. Alternatively, these components may be partially or fully integrated in a single microelectronic device. In the program memory 17 and the value memory 18 programs or values are stored, which are necessary for the operation of the combustion ^¬ engine 1. Specifically, in the Pro ^¬ program memory 17, a method of processing lubricant of the internal combustion engine 1 is implemented, which is executed during certain operating ranges of the internal combustion engine 1 by the arithmetic unit 16, as will be explained in more detail with reference to the figure description.

In addition, a so-called oil dilution model M_OIL is implemented in the program memory 17, with which the fuel input into the lubricant 6 and the fuel discharge from the lubricant 6 are determined. Such an oil dilution model M_OIL is described, for example, in DE 102010006580 B3, the contents of which are hereby incorporated by reference.

The control device 15 is associated with a plurality of sensors which detect different measured variables and in each case determine the measured value of the measured variable. Company sizes include the

Measured variables also derived therefrom. The control device 15 determines depending on at least one of

Measured variables and / or the operating variables manipulated variables, which are then converted into one or more actuating signals for controlling actuators by means of corresponding actuators. The sensors are for example an air mass meter, a

Temperature sensor 76 for the lubricant 6 in the crankcase 32, which outputs a signal T_OIL_l, a temperature sensor 77 for the lubricant 6 in the heater, which outputs a signal T_OIL_2, a temperature sensor for the coolant of the internal combustion engine 1, a crankshaft angle sensor, which detects a crankshaft angle , which is then assigned a speed, a lambda probe upstream of the exhaust gas 52 whose signal is characteristic of the air / fuel ratio in the combustion chamber of the cylinder 31st

The signals of these not explicitly shown sensors, which are generally necessary for the operation of the internal combustion engine 1, are indicated generally by the reference symbol ES.

The actuators are, for example, the throttle valve 21 in the intake tract 2, a shut-off valve 14 in an exhaust gas feed line 12 signals for further actuators, which operate to the

Internal combustion engine necessary, but not shown, are generally designated by the reference symbol AS.

The control device 15 determines inter alia as a function of at least part of the said input signals, in particular of the signals of the temperature sensors 76, 77 and the coolant temperature of the internal combustion engine 1, and taking into account the value for entry into the lubricant 6 obtained with the aid of the oil dilution model M_OIL When and how long to carry out an active heating of the lubricant 6.

The exhaust gas tract 5 of the internal combustion engine comprises an exhaust gas line 51 branching off from an unspecified exhaust manifold, in the course of which an exhaust gas catalytic converter 52 serving to convert harmful exhaust gas constituents is switched on and designed, for example, as a 3-way exhaust gas catalytic converter. The purified exhaust gas then passes through a silencer (not shown) into the environment.

From the main lubricant line 72, a lubricant supply line 73 branches off, which leads via a counterflow heat exchanger 8 and an electric heater 9 to a vapor separation device 10. The electric heater 9 is powered by the electronic control device 15 with electrical energy. The on-board electrical system of the internal combustion engine 1 is used as voltage source. used driven vehicle, ie the electric heating ^¬ device 9 with the board voltage UB, usually applied to 12 volts or in hybrid vehicles with 48 volts. The electrical heating of the lubricant 6 to a temperature above the boiling point of the registered in the lubricant 6 causes a perfect evaporation of these substances from the lubricant 6. The heated lubricant 6 and the now gaseous substances reach the Dampfabscheidevorrichtung 10, in which the gaseous substances be separated from the lubricant 6. As the vapor separation device 10, a known conventional device which allows the gaseous substances to be separated from the lubricant 6 can be used.

The separated, gaseous components are passed from the Dampfabscheidevorrichtung 10 by means of a vapor return line 75 in the suction pipe 22 at a point downstream of the Dros ^¬ selklappe 21 and fed with open inlet valve 41 of the combustion. The cleaned lubricant 6 is returned by the Dampfabscheide ^¬ device 10 by means of a lubricant return line 74 via the countercurrent heat exchanger 8 in the crankcase 32. In the countercurrent heat exchanger 8, the conveyed by the lubricant pump 7 cold lubricant 6 flows along a partition wall 81 and is already preheated by the flowing in the opposite direction, now heated lubricant 6, so that not the complete heating power for vaporizing the impurities alone applied by the electric heater 9 must become.

FIG. 2 shows a further exemplary embodiment for actively supporting the discharge of vaporizable impurities from the lubricant 6. In contrast to the structure described with reference to FIG. 1, the lubricant 6 to be cleaned from the registered substances is not heated to a temperature by means of an electrical heating device but with the aid of an exhaust gas-lubricant heat exchanger 11. heated, where the impurities evaporate. The remaining structure corresponds to the structure according to FIG. 1.

The cold lubricant 6 passes after passing through the

Counterflow heat exchanger 8 is preheated to the Ab ^¬ gas-lubricant heat exchanger 11. This is by means of an exhaust gas inlet pipe 12 to the exhaust pipe 51 upstream of a point of the exhaust gas catalytic converter 52 is connected to flow so that hot exhaust gas in the exhaust-lubricant heat exchanger 11 and the lubricant 6 can heat up. On the output side, the exhaust gas-lubricant heat exchanger 11 is likewise connected to the exhaust gas line 51 by means of an exhaust gas discharge line 13, so that the cooled exhaust gas can be discharged. In the From ^¬ gas inflow line 12 an operable by the electronic control device 15 electric shut-off valve 14 is switched so that in times when no heating of the lubricant 6 is necessary because the lubricant 6 in ^¬ game as already the Ver ^¬ internal-combustion engine with a longer operation 1 has a temperature at which the registered substances evaporate without active heating, this shut-off valve is closed and no hot exhaust gas can flow into the exhaust gas-lubricant heat exchanger 11.

In the illustrations of Figures 1 and 2, the countercurrent heat exchanger components, electric heater, exhaust gas lubricant heat exchanger, DampfabscheideVorrichtung are each shown as separate components. But it is also possible to integrate the countercurrent heat exchanger and the electric heater to a component in a common housing, as well as to accommodate the lubricant heat exchanger and the vapor separator in a common housing.

In FIG. 3, two different curves K1, K2 for the mass flow of mass flow FM are applied by the lubricant into the intake manifold of the internal combustion engine as a function of the time t after the start of the internal combustion engine at a time t0. The operation of the internal combustion engine is carried out with a fuel containing a high proportion of ethanol contains. The reference character Kl denotes a curve that reflects the discharge behavior in a conventional lubricant circuit, ie without active support of the discharge of fuel / water. In the case of a conventional lubricant circuit, it takes system-related a long time until the temperature of the lubricant is above the boiling points of the harmful components and the evaporation begins. Due to the high boiling point of ethanol (78 ° C at 1013mbar) is the fuel input in the

Lubricant higher than that of gasoline. This can lead to a sudden evaporation of the ethanol from the lubricant (time tl).

The reference symbol K2 designates a curve as it results according to the active support of the discharge according to the invention. It can be seen from this that very early after the start of the internal combustion engine, a continuous discharge of the vaporizable component ethanol takes place already in the warm-up phase.

Reference sign list

1 internal combustion engine

2 intake tract

21 throttle

22 intake manifold

3 engine block

31 cylinders

32 crankcase

33 crankshaft

34 connecting rod

35 pistons

36 oil pan

4 cylinder head

41 gas inlet valve

42 gas outlet valve

43, 44 valve drive

45 injection valve

46 spark plug

5 exhaust tract

51 exhaust pipe

52 catalytic converter

6 lubricants

7 lubricant pump

71 Suction line of the lubricant pump

72 main lubricant line

73 Lubricant supply line

74 lubricant return line

75 vapor return line

76 Temperature sensor lubricant in the crankcase Temperature sensor lubricant in heater

8 countercurrent heat exchanger

81 Partition wall of the countercurrent heat exchanger l2

9 electric heater

10 Dampfabscheide orrichtung

11 exhaust gas lubricant heat exchanger

12 exhaust gas supply line

13 exhaust gas drain line

14 shut-off valve

15 control device

16 arithmetic unit, processor

17 program memory

18 data memory, value memory

AS output signals

ES input signals

FM fuel mass flow discharge from lubricating oil

M OIL oil dilution mode11

Kl, K2 Curve discharge

UB board voltage

T OIL 1 Temperature lubricant in the crankcase

T OIL 2 Temperature lubricant in heater

Claims

claims

Process for the treatment of vaporizable impurities containing, in a crankcase (32) of an internal combustion engine (1) located, liquid lubricant (6), wherein

a partial mass flow of the lubricant (6) is branched off downstream of a lubricant pump (7) circulating the lubricant (6) in a closed circuit and fed via a counterflow heat exchanger (8) to a heating device (9, 11),

- by means of the heating device (9,11), the lubricant (6) is heated to a temperature at which the Verun ^¬ reinigungen pass into the vapor state,

the mixture of lubricant (6) and vaporous impurities is fed to a vapor separation device (10),

- The vapor deposited by the Dampfabscheidevorrichtung (10), vaporous impurities are supplied to the intake air of the internal combustion engine (1),

- The purified lubricant (6) from the Dampfab ^¬ separating device (10) via the counterflow heat exchanger (8) back into the crankcase (32) of the internal combustion engine (1) is passed.

A method according to claim 1, characterized in that the lubricant (6) by means of an electric heater (9) is heated, which is supplied by the on-board voltage (UB) of a by the internal combustion engine (1) angeverie ^¬ benen motor vehicle.

A method according to claim 1, characterized in that the lubricant (6) by means of an exhaust gas lubricant heat exchanger (11) is heated, the exhaust gas inlet (12) and exhaust gas discharge (13) to an exhaust pipe (51) of the internal combustion engine (1) upstream of a Ab ^¬ gas catalyst (52) are connected. Device for treating vaporizable impurities containing, in a crankcase (32) of an internal combustion engine (1) located lubricant (6), with

- A lubricant pump (7) which sucks the lubricant (6) from the crankcase (32) and circulates in a ge ^¬ closed circuit by means of at least one main ^¬ lubricating line (72),

a countercurrent heat exchanger (8) for heat exchange of lubricant (6) entering the counterflow heat exchanger (8) and leaving the counterflow heat exchanger (8),

wherein an inlet of the countercurrent heat exchanger (8) via a lubricant supply line (73) at a point downstream of the lubricant pump (7) to the main ^¬ lubrication line (72) is connected,

a heater (9, 11) connected downstream of the countercurrent heat exchanger (8) for heating the lubricant (6) to a temperature at which the impurities change to the vapor state,

- one, the heater (9,11) downstream

Vapor deposition apparatus (10) of the mixture of lubricant (6) and vaporous impurities is supplied via a vapor return line (75) for the separated vaporous impurities with an intake (2) of the combustion ^¬ combustion engine (1) and with a

Lubricant return line (74) for the treated lubricant (6) via the counterflow heat exchanger (8) to the crankcase (32) is connected.

Apparatus according to claim 4, characterized in that the lubricant return line (74) is connected at a position of the crankcase (32) which is above the level of the bottom of the crankcase (32) be ^¬ sensitive lubricant (6). Apparatus according to claim 4 or 5, characterized in that the heating device for the lubricant (6) is designed as an electric heater (9).

Apparatus according to claim 4 or 5, characterized in that the heating device for the lubricant (6) is designed as an exhaust gas lubricant heat exchanger (11) via an exhaust gas inlet (12) and an exhaust gas discharge (13) with an exhaust line (51). at a point upstream of an exhaust gas catalyst (52) of the internal combustion engine (1) is connected.

Apparatus according to claim 7, characterized in that in the exhaust gas supply line (12) of the exhaust gas lubricant heat exchanger (11) a shut-off valve (14) is turned on.