DE102009008831B4 - Internal combustion engine and method for monitoring a tank ventilation system and a crankcase ventilation system - Google Patents

Abstract

Internal combustion engine (1) with an intake air line (10), which contains a compressor (12) of an exhaust gas turbocharger (13) and a throttle valve (14), and with a tank ventilation system (20) and a crankcase ventilation system (21) which is connected to two connection points (30 , 31) in front of the compressor (12) and behind the throttle valve (14) are connected to the intake air line (10), wherein immediately at the connection points (30, 31) in each case a check valve (34, 35) is arranged and the tank ventilation system (20 ) and the crankcase ventilation system (21) are connected in common at the two connection points (30, 31) to the intake air line (10), wherein a vent line leading from the tank ventilation system (20) and the crankcase ventilation system (21) to the two connection points (30, 31) (29) is provided, characterized in that at the connection point (30) in front of the compressor (12) arranged check valve (34) insoluble with the Ansau Discharge line (10) and releasably connected to the vent line (29) is connected, and that at the connection point (31) behind the throttle valve (14) arranged check valve (35) is detachably connected to the intake air line (10) and the vent line (29) ,

Description

The invention relates to an internal combustion engine according to the preamble of claim 1, and to a method for monitoring a tank ventilation system and a crankcase ventilation system of an internal combustion engine according to the preamble of claim 5.

From the DE 103 00 592 A1 already an internal combustion engine of the aforementioned type is known, which has both a tank ventilation system and a crankcase ventilation system. The tank or crankcase ventilation gases discharged from the tank or crankcase ventilation system are sent to combustion by being directed into an intake air line of the internal combustion engine. Both separate between the tank ventilation system and the intake and between the crankcase ventilation system and the intake line there are two separate vent lines, one of which opens in front of the compressor of the exhaust gas turbocharger and the other behind the throttle valve into the intake air line. The two in front of the compressor of the exhaust gas turbocharger in the intake air line opening vent line are used for full load ventilation of the tank or the crankcase, while the opening behind the throttle valve in the intake air vent lines for partial load ventilation of the tank or the crankcase. All vent lines are equipped with valves with an adjustable opening degree.

Since a failure of the tank ventilation system and / or the crankcase ventilation system leads to the escape of unburned hydrocarbons into the environment, in most countries, diagnostic procedures have been required for some time to diagnose the proper functioning of the tank ventilation system and the crankcase ventilation system, so that a Escape of unburned hydrocarbons leading to early detection and repair. In addition, however, the California Air Resource Board (CARB) now also requires additional monitoring of the discharge points in Otto turbocharged internal combustion engines, at which tank ventilation gases and the crankcase ventilation gases are introduced into the intake air line. This is to prevent that it comes as a result of a release of the compounds at the connection points to an undesirable emission of unburned hydrocarbons into the environment.

While monitoring the connection point of the tank and crankcase ventilation line or lines, which open into the intake air line behind the throttle valve and serve to supply the venting gases into the intake air line in the suction mode, no problem, can be the connection point in front of the compressor of the turbocharger in the Intake air line opening tank and crankcase ventilation line or lines through which the vent gases are introduced in the boost pressure operation in the intake air, difficult to monitor. This is especially true when the cylinder charge of the internal combustion engine is not calculated from the measured values of an air mass meter arranged in the direction of flow of the intake air in front of the compressor in the intake air line, but from the measured values of a so-called intake manifold pressure sensor behind the throttle valve in a part usually referred to as a suction pipe the intake air line and thus located behind the discharge point of the vent gases in the boost pressure operation.

In principle, although it would be possible to form the connections of the tank and crankcase ventilation lines on the intake air line as permanent connections, but this raises problems in the case of the need for disassembly.

From the DE 102 49 720 A1 In addition, a pressure control valve for a crankcase ventilation system of an internal combustion engine is already known, which is arranged between a crankcase and an intake manifold of the internal combustion engine and connected to the intake manifold by two vent lines, one of which before a compressor of an exhaust gas turbocharger and the other behind a throttle valve into the exhaust pipe empties. Each of the two vent lines contains a check valve, both of which are integrated into line ports of the pressure control valve.

Furthermore, the document describes US 6,457,462 B2 a system for the combined venting of a cylinder crankcase and a collecting tank for the intermediate storage of hydrocarbons.

The publication DE 10 2006 016 339 A1 describes a method for the diagnosis of a tank ventilation system of a motor vehicle and a corresponding device. The tank ventilation system includes at least a first, downstream after a compressor in the intake of the engine opening first vent path and at least a second, upstream of the compressor in the intake opening second vent path. Provided is a diagnosis with at least two partial diagnoses, wherein the first partial diagnosis, concerning the first Venting path is performed when the intake manifold pressure in the mouth region of the first vent path is smaller than the tank system pressure, and the second part diagnosis, concerning the second vent path, is performed when the intake manifold pressure in the mouth region of the first vent path is greater than the tank system pressure. An error signal is provided when at least one of the partial diagnoses generates a partial error signal.

Furthermore, the document describes DE 10 2005 043 735 A1 a vent valve and the publication DE 20 2004 011 882 U1 a crankcase ventilation for an internal combustion engine with an exhaust gas turbocharger.

Proceeding from this, the present invention seeks to provide an internal combustion engine and a method of the type mentioned above, which allow a monitoring of the discharge points of the venting gases in the intake air line in a relatively simple manner.

This object is achieved in the internal combustion engine according to the invention characterized in that the non-return valve disposed at the junction before the compressor is permanently connected to the intake air line and releasably connected to the vent line, and that arranged at the junction behind the throttle check valve releasably connected to the intake air line and the vent line connected is. In principle, therefore, it is provided that a check valve is arranged directly at the connection points at which the venting gases are introduced into the intake air line, and the tank ventilation system and the crankcase ventilation system are connected together at the two connection points to the intake air line, one of the tank ventilation system and the crankcase ventilation system provided to the two connection points leading vent line.

The invention is based on the idea that from the DE 102 49 720 A1 known check valves away from the pressure control valve to the system boundaries of the crankcase ventilation system and the tank ventilation system, ie directly to the intake air line to lay. As a result, leakage between the tank ventilation system and the crankcase ventilation system on the one hand and the intake air line on the other hand can be monitored without additional measures with a pressure sensor which is located in the intake air behind the throttle and serves to determine a cylinder filling, however, also advantageous for monitoring the discharge points of the vent gases can be used from the tank ventilation system and the crankcase ventilation system in the intake air line in the suction and in the boost pressure operation.

In order to keep the number of required components and assembly costs low, a preferred embodiment of the invention provides that the tank ventilation system and the crankcase ventilation system are connected at the two connection points together to the intake air line.

In this case, with the help of the pressure sensor, both a leakage between the tank ventilation system and the crankcase ventilation system on the one hand and the intake air line on the other hand, as well as a defect or jamming of an arranged directly at the junction before the compressor open check valve be diagnosed or found, while a defect or jamming of the Junction located behind the throttle valve arranged closed check valve advantageously in the course of monitoring or diagnosis of a tank ventilation valve of the tank ventilation system is detected.

While to facilitate the replacement arranged at the junction behind the throttle check valve can be detachably connected to the intake air line and leading to the tank ventilation system and the crankcase ventilation system vent line, which is arranged at the junction before the compressor check valve according to a preferred embodiment of the invention insoluble with the Intake air line connected. As a result, on the one hand, beyond this check valve, it is no longer possible to disengage the connection between the tank ventilation system and the crankcase ventilation system on the one hand and the intake air line on the other hand. On the other hand, in the case of a pressure in the vent line exceeding the ambient pressure, an escape of unburned hydrocarbons into the environment can be prevented. However, this check valve can be releasably connected to the vent line, so that it can be solved in the event of a line break from the check valves and replaced.

When the non-return valve located at the junction behind the throttle detaches from the intake air line and the vent line leading to the tank vent system and the crankcase ventilation system, or when the check valve located at the junction upstream of the compressor disengages from the vent line, an ambient pressure is immediately established in the vent line a, which allows detection of the leakage.

In the following the invention will be explained in more detail with reference to an embodiment shown in the drawing. Show it:

1 a schematic representation of parts of an internal combustion engine with an exhaust gas turbocharger, a tank ventilation system and a crankcase ventilation system;

2 a representation of the pressure in the intake air pipe in front of the compressor of the exhaust gas turbocharger and behind a throttle valve in dependence on the load and speed of the internal combustion engine.

1 shows a schematic sectional view of parts of a supercharged gasoline engine 1 with an engine block 2 , one the crankshaft 3 and a crank room 4 the internal combustion engine 1 surrounding crankcase 5 , as well as at least one piston 6 that has a connecting rod 7 with the crankshaft 3 is connected and in an associated cylinder 8th of the motor 1 moved up and down. The combustion of the fuel-air mixture in a combustion chamber 9 of the cylinder 8th required air is the combustion chamber 9 through an intake air line 10 fed to an air filter 11 , a compressor 12 an exhaust gas turbocharger 13 and a throttle 14 contains. The throttle 14 is in the flow direction of the air behind the compressor 12 and in front of you usually as a suction tube 15 designated part of the intake air line 10 arranged. The combustion air from the combustion chamber 9 of the cylinder 8th is through an exhaust manifold 16 and an exhaust pipe 17 dissipated, which is a turbine 18 the exhaust gas turbocharger 13 contains. To fill the cylinder 8th or in the cylinder 8th to determine the supplied air mass is behind the throttle 14 in the intake manifold 15 a pressure sensor 19 provided for measuring the intake manifold pressure, from which then the air mass is calculated according to the relationship p · V = m · R · T.

To prevent emission of unburned hydrocarbons into the environment, the internal combustion engine includes 1 continue a tank ventilation system 20 and a crankcase ventilation system 21 ,

With the tank ventilation system 20 can be a fuel tank 22 the internal combustion engine 1 vented and removed from the fuel tank 22 discharged fuel vapors or tank vent gases for combustion in the cylinder 8th into the intake air line 10 be supplied. The tank ventilation system 20 includes one with the fuel tank 22 communicating activated carbon filled fuel vapor storage tanks 23 in which the fuel vapors or tank vent gases are cached, and a regeneration line 24 by which to regenerate the activated carbon air from the environment through the storage tank 23 into the intake air line 10 is sucked when a between the storage tank 23 and the intake air line 10 arranged tank vent valve 25 is opened.

With the crankcase ventilation system 21 can the crankcase 4 the internal combustion engine 1 be actively vented by selectively injecting air into the crankcase 5 is supplied and by the crankcase ventilation gases, ie the supplied, with oil mist from the crankcase 4 mixed air and the so-called blow-by gases, ie during operation of the internal combustion engine 1 between cylinders 8th and pistons 6 passing combustion gases, also for combustion in the intake air line 10 be supplied. The crankcase ventilation system 21 includes one with the crankcase 4 communicating oil separator 26 and one between the oil separator 26 and the intake air line 10 arranged pressure control valve 27 ,

To monitor the proper functioning of the tank ventilation system 20 and the crankcase ventilation system 21 serves a diagnostic module 28 That with the tank vent valve 25 , the pressure control valve 27 and the pressure sensor 19 connected is.

The tank vent valve 25 of the tank ventilation system 20 and the pressure control valve 27 of the crankcase ventilation system 21 are through a common vent line 29 with the intake air line 10 connected. This vent line 29 is with its one end at a first junction 30 behind the air filter 11 and in front of the compressor 12 and with its opposite end at a second junction 31 behind the throttle 14 to the intake air line 10 connected and communicates between the two ends via two branches 32 and 33 with the tank vent valve 25 of the tank ventilation system 20 or the pressure control valve 27 of the crankcase ventilation system 21 so that the vent line 29 from the tank ventilation system 20 and the crankcase ventilation system 21 shared.

Immediately at the two connection points 30 and 31 is each a check valve 34 and 35 arranged, the entry of air from the intake air line 10 in the common vent line 29 prevent. On the one hand, this ensures that there is no air at the compressor 12 and at the throttle 14 past the vent line 29 can flow and prevents, on the other hand, that air from the intake air line 10 through the vent line 29 and the branches 32 or 33 in the tank ventilation system 20 or the crankcase ventilation system 21 can get. The check valve 34 at the first junction 30 is insoluble with the intake air line 10 and detachable with the one end of the vent line 29 connected while the check valve 35 at the second junction 31 detachable with the intake air line 10 and the opposite end of the vent line 29 can be connected.

In boost pressure operation of the exhaust gas turbocharger 13 become the tank and crankcase ventilation gases due to the pressure conditions in the intake air line 10 and in the vent line 29 at the first junction 30 through the open check valve 34 through into the intake air line 10 while in suction mode at the second connection point 31 through the open check valve 35 through into the intake air line 10 be initiated.

As in 1 is a pressure p1 in the intake air line 10 in front of the compressor 12 less than or equal to the ambient pressure p_Environment, while a pressure p2 in the intake air line 10 behind the compressor 12 and in front of the throttle 14 is equal to the sum of the pressures p1 + p_load, where p_load is the boost pressure of the compressor 12 is. The pressure p3 in the intake manifold 15 behind the throttle 14 is equal to the difference of the pressures p2 - p_Drossel, where p_Drossel is the pressure loss at the throttle 14 is.

2 shows the relationship between p1 and p3 depending on the load and the speed of the internal combustion engine 1 , wherein the area I represents the relationship in the suction mode and the area II the relationship in the boost pressure operation.

The pressure in the vent line 29 is referred to as p4 and corresponds to the respective lower pressure of p1 and p3, since both in the suction mode and in the boost pressure mode each one of the two check valves 34 . 35 is open. On the other hand, this means that apart from the special case p1 = p3 always one of the two check valves 34 . 35 must be closed.

Inside the crankcase 4 is from the pressure control valve 27 a low negative pressure is set, ie a pressure which is slightly below the ambient pressure p_Environment. This pressure control by the pressure control valve 27 is required because z. B. in idle mode, a pressure p4 = p3 sets, which is approximately 300 mbar absolute, which in idle mode for the crankcase 4 way too low.

The tight connection between the check valve 34 and the intake air line 10 is required in case of disconnecting the connection at the first connection point 30 a discharge of vent gases from the vent line 29 into the environment when in pressure boost operation, the pressure p4 in the vent line 29 is higher than the ambient pressure p_Environment.

When the vent line 29 has a leak that can occur anywhere, for example, by a breakage of the vent line 29 or by loosening the connection between the vent line 29 and one of the two check valves 34 . 35 , the pressure p4 is inside the vent line 29 equal to the ambient pressure p_Environment. Because in this state tank or crankcase ventilation gases from the vent line 29 can escape into the environment, such a condition must be detected by the diagnosis. This is also the case with the described tank and crankcase ventilation system, because either the idling speed in the suction mode is too high and can not be adjusted because of the supply of too much fresh air in the intake manifold, because the intake manifold pressure measured for filling adjustment in relation to the position of the throttle valve 14 is implausible or the diagnosis of the tank ventilation leads to a detection of the leakage.

If the check valve 34 stuck in its open position, the pressure p4 within the vent line 29 equal to the pressure p1. This causes the air in the boost pressure operation from the environment through the check valve 34 is sucked, resulting in a slightly smaller leakage current into the intake manifold 15 but that of the pressure sensor 19 detected pressure p3 in the intake manifold 15 also increases and makes a detection of the leakage possible. If the check valve 34 stuck in its closed position, this is alone with the help of the pressure sensor 19 not diagnosable. In such a case, however, the vent gases from the tank ventilation system 20 and the crankcase ventilation system 21 during suction operation at the second connection point 31 through the check valve 35 through the intake manifold 15 supplied when the pressure p4 is greater than the pressure p3.

If the check valve 35 stuck in its closed position, this may be due to a diagnosis of the tank vent valve 25 be recognized, which leads to an improvement over known systems with respect to the crankcase ventilation.

LIST OF REFERENCE NUMBERS

1

Internal combustion engine

2

block

3

crankshaft

4

crankcase

5

crankcase

6

piston

7

pleuel

8th

cylinder

9

combustion chamber

10

intake air line

11

air filter

12

compressor

13

turbocharger

14

throttle

15

suction tube

16

exhaust manifold

17

exhaust pipe

18

turbine

19

pressure sensor

20

Tank ventilation system

21

Crankcase ventilation system

22

Fuel tank

23

storage container

24

regenerating line

25

Tank ventilation valve

26

oil separator

27

Pressure control valve

28

diagnostic module

29

common vent line

30

first connection point

31

second connection point

32

junction

33

junction

34

check valve

35

check valve

Claims (5)

Internal combustion engine ( 1 ) with an intake air line ( 10 ), which is a compressor ( 12 ) of an exhaust gas turbocharger ( 13 ) and a throttle valve ( 14 ) and with a tank ventilation system ( 20 ) and a crankcase ventilation system ( 21 ) at two connection points ( 30 . 31 ) in front of the compressor ( 12 ) and behind the throttle ( 14 ) to the intake air line ( 10 ) are connected directly to the connection points ( 30 . 31 ) each a check valve ( 34 . 35 ) and the tank ventilation system ( 20 ) and the crankcase ventilation system ( 21 ) together at the two connection points ( 30 . 31 ) to the intake air line ( 10 ), one of the tank ventilation system ( 20 ) and the crankcase ventilation system ( 21 ) to the two connection points ( 30 . 31 ) leading vent line ( 29 ), characterized in that at the junction ( 30 ) in front of the compressor ( 12 ) arranged check valve ( 34 ) unsolvable with the intake air line ( 10 ) and detachable with the vent line ( 29 ), and that at the junction ( 31 ) behind the throttle ( 14 ) arranged check valve ( 35 ) detachable with the intake air line ( 10 ) and the vent line ( 29 ) connected is. Internal combustion engine according to claim 1, characterized in that the tank ventilation system ( 20 ) with the vent line ( 29 ) connected tank vent valve ( 25 ). Internal combustion engine according to one of the preceding claims, characterized in that the crankcase ventilation system ( 21 ) with the vent line ( 29 ) connected pressure control valve ( 27 ). Internal combustion engine according to one of the preceding claims, characterized by a behind the throttle valve ( 14 ) in the intake air line ( 10 ) arranged pressure sensor ( 19 ) for determining a cylinder filling. Method for monitoring a tank ventilation system and a crankcase ventilation system of an internal combustion engine according to one or more of the preceding claims, characterized in that leakage between the tank ventilation system ( 20 ) and the crankcase ventilation system ( 21 ) on the one hand and the intake air line ( 10 ) on the other hand by monitoring the pressure (p3) behind the throttle valve ( 14 ), or that a defect or jamming at the junction ( 30 ) in front of the compressor ( 13 ) arranged open check valve ( 34 ) by monitoring the pressure (p3) behind the throttle valve ( 14 ), or that a defect or jamming at the junction ( 31 ) behind the throttle ( 14 ) arranged closed check valve ( 35 ) by a diagnosis of a tank ventilation valve ( 25 ) of the tank ventilation system ( 20 ) is detected.

Images