DE102012100115B4 - Gas mixture detection module for LPG for motor vehicles and associated method - Google Patents

Abstract

A device (1) and a method are used to determine the mixing ratio of a liquid gas mixture (2), in particular LPG (liquefied petroleum gas). The gas mixture (2) is intended for combustion in a motor (19) and is supplied to it from a gas tank (3). A temperature sensor (8) measures the temperature of the liquid gas mixture (2). A pressure sensor (9) serves to measure the pressure of the gas mixture (2) in the gas tank (3). A measured gas mixture detection module (7) connected to the temperature sensor (8) and the pressure sensor (9) supplies the measured values to the temperature and the pressure. Based on saturation vapor pressure curves (20), the gas mixture detection module (7) determines the current mixing ratio of the gas mixture (2) for different mixing ratios of the gas mixture (2). Depending on the current mixing ratio of the gas mixture (2), the gas control unit (13) is controlled to ensure optimum combustion in the gas combustion operation without adversely affecting the gasoline combustion operation.

Description

TECHNICAL FIELD OF THE INVENTION

The invention relates to a device and a gas mixture detection module for determining the mixing ratio of a liquid gas mixture, wherein the gas mixture is intended for combustion in an engine.

The invention further relates to a method for controlling a motor operated with a liquid gas mixture.

The gas mixture is liquefied gas, d. H. a propane and butane-containing gas mixture. LPG is also commonly referred to as LPG ("Liquefied Petroleum Gas") or LPG. Such LPG can be used for combustion in gasoline engines commercially available vehicles. Other applications include combustion in engines of boats or work machines or in combined heat and power plants.

STATE OF THE ART

From the German patent application DE 10 2004 044 178 A1 For example, an apparatus and method for controlling fuel injection for a liquid gas injection engine is known. The mixing ratio of propane and butane in the LPG is determined to control the fuel injection time and the fuel injection period by a map depending thereon. For this purpose, the temperature and the pressure of the liquefied gas is determined, the pressure being determined by means of a fuel pressure sensor already present in the engine. The determination of the propane content is dependent on a speed which is referred to in this prior art document as "engine speed". However, in the opinion of the applicant, this is obviously not the speed of the motor of the motor vehicle, but of the gas fuel pump. Since the pressure sensor is arranged downstream of the gaseous fuel feed pump, when determining the mixing ratio of the gas mixture and the difference in rotational speed between the off state and the on state of the motor vehicle (and thus the gas fuel pump) must be considered. In other words, the gaseous fuel feed pump has an effect on the measured pressure and must be eliminated by depositing a specific table for the gas fuel pump used. The mixing ratio of the gas contents of the fuel is calculated once at the initial starting of the vehicle.

Another device and a method for determining the mixing ratio of a liquid gas mixture are known from the German patent applications DE 24 04 557 and DE 36 15 679 A1 known. The mixing ratio of the gas mixture consisting of butane and propane is determined on the basis of the pressure and the temperature of the gas mixture. The liquefied gas is vaporized in a pressure regulator / evaporator and introduced into the combustion chamber in the vapor state. The pressure of the gas mixture is determined in the pressure regulator / evaporator by means of a mechanical-pneumatic flap control. The measurement does not take place in the sense of defined individual measurement processes, but by a permanent pressure equalization control.

The German patent DE 10 2006 022 357 B3 shows a method and apparatus for determining the mixing ratio and for controlling the engine of a motor vehicle in the combustion of natural gas. The natural gas has as its main component a gaseous component - namely methane - on. It should continue to have liquid ingredients - especially ethane, propane and butane - have. The gaseous components are removed from the tank. In the first taking place of methane, the pressure prevailing in the tank decreases accordingly. Later, the other constituents of the mixture should change from the liquid to the gaseous state and the mixing ratio should then be determined.

It is known from the document HTTP://WWW.MOTOR-TALK.DE/FORUM/VAMPFDRUCKKURVENFUER-MISCHUNGEN-PB-95-5-BIS-30-70-T1403005.HTML of March 30, 2007, that the temperature and the Pressure of liquefied gas can be used with the help of saturation vapor pressure curves for determining the mixing ratio of propane and butane. The mixing ratio should be determined for the LPG in the tank of a dispenser.

From the previously filed and post-published German patent application DE 10 2011 111 390 A1 For example, a method and apparatus for determining the mixing ratio of LPG are known.

From the German patent application DE 44 46 081 A1 a fuel control system for an internal combustion engine of motor vehicles is known, which performs a detected pressure and temperature signal at the gas injection nozzle for compressed gas to equalize the amount of fuel. A Gasmengenabstimmung the injected or einzubasenden amount of gas with respect to the present at the gas nozzle temperature and by the Pressure reducer applied gas pressure is achieved by a stored map.

OBJECT OF THE INVENTION

The object of the invention is to provide a device and a method with which the mixing ratio of a liquid gas mixture can be reliably and universally determined and the engine combusting the gas mixture can be regulated as a function of this with permanent compliance with the permissible exhaust gas values.

SOLUTION

The object of the invention is achieved with the features of the independent claims.

Further preferred embodiments according to the invention can be found in the dependent claims.

DESCRIPTION OF THE INVENTION

The invention relates to a device for determining the mixing ratio of a liquid gas mixture of a first liquid gas and a second liquid gas. The gas mixture is intended for combustion in an engine and is supplied to it from a gas tank. The apparatus includes a temperature sensor for measuring the temperature of the liquid gas mixture, a pressure sensor for measuring the pressure of the gas mixture in the gas tank, and a gas mixture detection module connected to the temperature sensor and the pressure sensor. The gas detection module is supplied with the measured values of temperature and pressure. Based on saturation vapor pressure curves for various mixing ratios of the gas mixture, the gas detection module determines the current mixing ratio of the gas mixture.

The invention further relates to a gas mixture detection module for determining the mixing ratio of a liquid gas mixture of a first liquid gas and a second liquid gas. The gas mixture is intended for combustion in an engine and is supplied to it from a gas tank. The mixed gas detection module is configured and configured to receive a value of the pressure of the gas mixture in the gas tank and the temperature of the liquid gas mixture. The gas mixture detection module is designed and determined for determining the actual mixing ratio of the gas mixture by comparing the measured values of the temperature and the pressure of the gas mixture with the corresponding values in saturation vapor pressure curves for different mixing ratios of the gas mixture.

• – Messen der Temperatur des flüssigen Gasgemisches mit einem Temperatursensor,
• – Messen des Drucks des Gasgemisches in dem Gastank mit einem Drucksensor,
• – Übertragen der gemessenen Werte der Temperatur und des Drucks des Gasgemisches an ein Gasgemischerkennungsmodul, und
• – Bestimmen des Mischungsverhältnisses des Gasgemisches mit dem Gasgemischerkennungsmodul durch einen Vergleich der gemessenen Werte der Temperatur und des Drucks des Gasgemisches mit den entsprechenden Werten in Sättigungsdampfdruckkurven für verschiedene Mischungsverhältnisse des Gasgemisches.

The invention also relates to a method for determining the mixing ratio of a liquid gas mixture of a first liquid gas and a second liquid gas. The gas mixture is intended for combustion in an engine and is supplied to it from a gas tank. The method comprises the following steps:

• Measuring the temperature of the liquid gas mixture with a temperature sensor,
• Measuring the pressure of the gas mixture in the gas tank with a pressure sensor,
• - Transferring the measured values of the temperature and the pressure of the gas mixture to a gas mixture detection module, and
• - Determining the mixing ratio of the gas mixture with the gas mixture detection module by comparing the measured values of the temperature and the pressure of the gas mixture with the corresponding values in saturation vapor pressure curves for different mixing ratios of the gas mixture.

• – Messen der Temperatur des flüssigen Gasgemisches mit einem Temperatursensor,
• – Messen des Drucks des in einem Gastank befindlichen Gasgemisches mit einem Drucksensor,
• – Übertragen der gemessenen Werte der Temperatur und des Drucks des Gasgemisches an ein Gasgemischerkennungsmodul,
• – Bestimmen des Mischungsverhältnisses des Gasgemisches mit dem Gasgemischerkennungsmodul durch einen Vergleich der gemessenen Werte der Temperatur und des Drucks des Gasgemisches mit den entsprechenden Werten in Sättigungsdampfdruckkurven für verschiedene Mischungsverhältnisse des Gasgemisches, und
• – Regeln eines Gassteuergeräts zur Anpassung an das aktuelle Mischungsverhältnis des Gasgemisches, wobei das Gassteuergerät ein Gaseinblas- bzw. Gaseinspritzzeiten enthaltendes Kennfeld aufweist, wobei die Gaseinblas- bzw. Gaseinspritzzeiten in Abhängigkeit von dem aktuellen Mischungsverhältnis des Gasgemisches eingestellt werden.

The invention further relates to a method for controlling an engine operated with a liquid gas mixture, wherein the liquid gas mixture comprises a first liquid gas and a second liquid gas. The method comprises the following steps:

• Measuring the temperature of the liquid gas mixture with a temperature sensor,
• Measuring the pressure of the gas mixture in a gas tank with a pressure sensor,
• Transferring the measured values of the temperature and the pressure of the gas mixture to a gas mixture detection module,
• Determining the mixing ratio of the gas mixture with the gas mixture detection module by comparing the measured values of the temperature and the pressure of the gas mixture with the corresponding values in saturation vapor pressure curves for different mixing ratios of the gas mixture, and
• - Rules of a gas control device for adaptation to the current mixing ratio of the gas mixture, wherein the gas control device comprises a Gaseinblas- or gas injection times containing map, wherein the Gaseinblas- or gas injection times are set in dependence on the current mixing ratio of the gas mixture.

definitions

Gas mixture: In this application, a gas mixture is understood as meaning a mixture of at least two different gases. However, the gas mixture may also be three, four or more contain different gases, it being possible to determine the proportions of these other gases in the gas mixture or even neglect them. The proportions are determined in percent by volume.

Further description

The new device, the new gas mixture detection module and the new methods are universally applicable to many different vehicles and can be retrofitted. This applies both to an injection of the liquid gas and an injection of the gaseous gas. The present invention is applicable to all common gas mixture combustion plants, in particular venturi plants, semi-sequential plants, fully sequential plants and liquefied gas injection plants.

The respective type of system must be taken into account when arranging the sensors. In a liquefied gas injection, the sensors are arranged in the gas tank or arranged in the so-called multi-valve. Downstream there are no representative values for LPG injection because the LPG delivery pump pressure and the temperature are distorted by the engine radiating heat.

There is no dependency on the particular engine used, since pressure and temperature are determined independently of influencing variables of the respective engine. The temperature sensor measures the temperature of the liquid gas mixture. For this purpose, it can be arranged in particular in the gas tank, a line leading away from it or the gas mixture detection module. The pressure sensor is used to measure the pressure that the gas mixture has in the gas tank. In this case, the pressure sensor itself need not be arranged in the gas tank, but merely measure the pressure prevailing in the gas tank. Therefore, the pressure sensor so downstream of the gas tank in a line or z. B. the gas mixture detection module, which are connected in terms of pressure with the gas tank, so that the pressure prevailing in the gas tank pressure also applied there and thus is measurable.

The measured values of temperature and pressure are then fed as analog or digital electrical signals via corresponding lines to the gas mixture detection module. The gas mixture detection module is programmed to have saturation vapor pressure curves for different mixing ratios of the gas mixture. The saturation vapor pressure is known to be the vapor phase pressure of a substance when the liquid and vapor phases are in equilibrium. The pressure over a mixture of several different gases depends on the mixing ratio of the gases. On the basis of the determined pressure at a likewise determined temperature, therefore, the current mixing ratio of the gas mixture in volume percent can be determined.

The mixing ratio of the gas mixture changes, for example, from gas station to gas station and also from winter to summer, as more butane is contained in the gas mixture in summer. Since butane has a higher burning energy than propane, with a relatively larger proportion of propane more gas mixture per unit time in the engine must be burned.

The mixed gas detection module is preferably configured to repeatedly perform the determination of the actual mixing ratio of the gas mixture at defined spaced time intervals. It is then not a permanent measurement in the sense of a pressure compensation control, but defined and temporally spaced measurements that are repeated several times. In particular, the time interval may be between about 5 seconds and 10 minutes, between about 20 seconds and 5 minutes, and preferably about 30 seconds.

The determination of the current mixing ratio of the gas mixture is thus carried out several times in succession after starting the engine with the engine running. This is preferably done over the entire operating life of the engine. This allows a much more accurate control of the gas control unit of the engine can be realized. By this new rule z. B. occurring during operation temperature fluctuations are well balanced. One reason for comparatively high temperature fluctuations is the arrangement of the gas tank of the vehicle outside of the vehicle, so that the airstream leads to a cooling of the gas tank and the gas mixture contained therein. Another reason is the parking of the vehicle in a garage and the subsequent operation at minus temperatures in winter or even in strong sunlight in the summer. Another reason for LPG injection is the return of the liquefied gas heated by the engine to the gas tank. These differences in temperature during operation lead to a change in the density of the gas mixture and thus require an adaptation of the characteristic map of the gas control unit, in order to continue to ensure optimum combustion and compliance with the exhaust gas values.

Another advantage of this repeated measurement and regulation even after starting the engine is that the Petrol control unit is not unintentionally adjusted. The gasoline control unit usually works in the gas mode permanently with. Normally, the gasoline injection signal is removed from the fuel injector and supplied to the gas controller. However, the fuel control unit is still connected to the lambda probe and receives from these values on whether the combustion was carried out properly and no partial combustion has occurred or is an over-greasing. This is also known as OBD capability (OBD = on-board diagnostics). The gasoline injection values in the gasoline control unit are thus constantly adapted further. If now the gas quality changed in the gas combustion operation and the gas control unit - as in the prior art would not be readjusted, an improper combustion would take place, they are reported by the lambda probe to the gasoline control unit and then perform the gasoline control unit readjustment. However, this readjustment would not be adjusted to the gasoline combustion - but to the gas combustion - and thus led to a misalignment of the gasoline control unit. The new multiple determination of the mixing ratio of the gas mixture during the gas combustion operation thus surprisingly also ensures that proper combustion takes place in gasoline combustion operation. The occurrence of engine damage is prevented.

This operation is also referred to as master / slave operation. The gasoline control unit is the master control unit and the gas control unit is the slave control unit. The gasoline control unit operates effectively, especially when starting the engine, wherein at a gas injection at a water temperature of about 30 ° C to 40 ° C of the pressure regulator / evaporator is switched to the gas mode. The gasoline control unit then also works (ineffective, see above) in gas mode.

The liquid gas mixture has at least two different liquid gases, which are propane and butane. Experience has shown that the mixing ratio varies between approximately 5% and 95%. The higher the propane content, the higher the vapor pressure.

Depending on the determined values, the gas control unit u. a. with regard to the gas injection times (during the gas injection) or the gas injection times (during the gas injection). These and other values are contained in different gas maps depending on the mixing ratio of the gas mixture.

Advantageous developments of the invention will become apparent from the claims, the description and the drawings. The advantages of features and of combinations of several features mentioned in the introduction to the description are merely exemplary and can come into effect alternatively or cumulatively, without the advantages having to be achieved by embodiments according to the invention. Without thereby altering the subject matter of the appended claims, as regards the disclosure of the original application documents and the patent, further features can be found in the drawings, in particular the illustrated geometries and the relative dimensions of several components and their relative arrangement and operative connection. The combination of features of different embodiments of the invention or of features of different claims is also possible deviating from the chosen relationships of the claims and is hereby stimulated. This also applies to those features which are shown in separate drawings or are mentioned in their description. These features can also be combined with features of different claims. Likewise, in the claims listed features for further embodiments of the invention can be omitted.

The features mentioned in the patent claims and the description are to be understood in terms of their number that exactly this number or a greater number than the said number is present, without requiring an explicit use of the adverb "at least". If, for example, a temperature sensor is mentioned, this is to be understood as meaning that exactly one temperature sensor, two temperature sensors or more temperature sensors are present. If, on the other hand, only the exact number of a feature is to be specified, the adjective "exactly" before the respective feature is used.

BRIEF DESCRIPTION OF THE FIGURES

In the following the invention will be further explained and described with reference to preferred embodiments shown in the figures.

1 shows a view of a first exemplary embodiment of the new device in which the gaseous gas mixture is injected into the engine.

2 shows a view of a second exemplary embodiment of the new device in which the liquid gas mixture is injected directly into the engine.

3 shows a view of a third exemplary embodiment of the new device, in the liquid gas mixture is injected into the intake passage of the engine.

4 shows a first saturation vapor pressure curve for a gas mixture with a proportion of propane of 20% and a proportion of butane of 80%.

5 shows a first gas map for the gas mixture according to 4 ,

6 shows a second saturation vapor pressure curve for a gas mixture with a proportion of propane of 40% and a proportion of butane of 60%.

7 shows a second gas map for the gas mixture according to 6 ,

8th shows a third saturation vapor pressure curve for a gas mixture with a proportion of propane of 50% and a proportion of butane of 50%.

9 shows a third gas map for the gas mixture according to 8th ,

10 shows a fourth saturation vapor pressure curve for a gas mixture with a proportion of propane of 85% and a proportion of butane of 15%.

11 shows a fourth gas map for the gas mixture according to 10 ,

DESCRIPTION OF THE FIGURES

1 shows a first exemplary embodiment of a new device 1 for determining the mixing ratio of a liquid gas mixture 2 of at least a first liquid gas and a second liquid gas. In the gas mixture 2 it is liquefied gas, ie a gas mixture containing propane and butane 2 , Such liquefied petroleum gas (LPG) is used in particular for combustion in gasoline engines of motor vehicles. However, other applications, such as combustion in engines of boats or cogeneration units, are also possible.

The device 1 has a gas tank 3 on, in which the gas mixture 2 is received in liquid form. Above the liquid level is the vaporous phase of the gas mixture 2 , In the present case, it is the gas tank 3 to the gas tank of a motor vehicle, which the gas mixture 2 in his engine 19 burns. However, it could also be the gas tank 3 a tanker truck or gas station.

At the gas tank 3 is a so-called multi-valve 4 arranged. The multi-valve 4 provides various functions in a known manner, namely in particular an overfill protection, a withdrawal control, an overpressure control, a shut-off of the gas flow in the case of defective lines and a fill level indicator. The multi-valve is for the level indicator 4 a swimmer 5 on. Furthermore, a line 6 through the multi-valve 4 in the interior of the gas tank 3 guided and used for sucking the liquid gas mixture 2 ,

Downstream of the multi-valve 4 is the lead 6 then with a new gas mixture detection module 7 connected. The gas mixture detection module 7 is in turn with a temperature sensor 8th and a pressure sensor 9 electrically connected. In the embodiment of the gas mixture detection module shown here 7 are the temperature sensor 8th and the pressure sensor 9 into the housing of the mixed gas detection module 7 integrated so that they are in the representation of 1 are shown only schematically. The sensors 8th . 9 but could also outside the housing of the gas mixture detection module 7 be arranged.

From the gas mixture detection module 7 becomes the conduit 6 then to an evaporator / pressure regulator 10 continued, in turn, over the line 6 with gas injection valves 11 connected is. The gas injection valves 11 are via an electrical line 12 with a gas control unit 13 connected. The gas control unit 13 is in turn via electrical lines 14 with the gas mixture detection module 7 connected.

Another electrical line 15 connects the gas control unit 13 with a gasoline control unit 16 , The gasoline control unit 16 is in turn via an electrical line 17 with gasoline injection valves 18 connected. Both the gas injection valves 11 as well as the gasoline injection valves 18 are part of the engine 19 , which, apart from the features resulting from the peculiarities of the present invention, is a conventional gasoline engine that has been converted for the combustion of liquefied petroleum gas. Accordingly, it is understood that both the gas injection valves 11 as well as the gasoline injection valves 18 for introducing the respective fuel into a common combustion chamber of the engine 19 serve and the appearance of 1 thus in this regard is only schematically.

The following are the different modes of operation of the engine 19 and the modes of action of the new gas mixture detection module 7 described in more detail:

Gasoline operation

If the engine 19 Burns gasoline in petrol mode, this is in the usual way by means of gasoline injection valves 18 in the combustion chamber of the engine 19 brought in. The regulation of petrol injectors 18 also takes place in the usual way by the gasoline control unit 16 , It is understood that the gasoline is supplied via the fuel tank, not shown here.

The gasoline combustion operation may in particular when starting the engine 19 be active. This is because the evaporator / pressure regulator 10 must first reach a certain operating temperature before it can be switched to the gas combustion operation.

The gasoline control unit 16 is connected in a known manner with the lambda probe, not shown here, and receives from these values on whether the combustion was carried out properly. Depending on the fuel injection values are based on gasoline fuel maps in the gasoline control unit 16 constantly adjusted.

Gas combustion operation

In gas combustion operation, the gas mixture is now used instead of gasoline 2 the combustion chamber of the engine 19 fed. The supply takes place via the line 6 , the multi-valve 4 , the gas detection module 7 , the evaporator / pressure regulator 10 and the gas injection valves 11 , In this case flows in this evaporator embodiment of the device 1 according to 1 the liquid gas into the evaporator / pressure regulator 10 and is converted in this in the gaseous state. The supply into the combustion chamber then takes place in the gaseous state via the gas injection valves 11 ,

In the prior art, in the gas combustion mode as well as in the gasoline combustion mode, only an adjustment of the supply of the respective fuel would then be carried out as a function of the signal of the lambda probe. Here now according to the invention comes the new gas mixture detection module 7 to bear, the function of which will be described further below.

Gas mixture recognition

The new gas mixture detection module 7 is with the temperature sensor 8th and the pressure sensor 9 connected. The temperature sensor 8th serves to measure the temperature of the liquid gas mixture 2 , In the illustrated embodiment, the temperature sensor 8th into the housing of the gas detection module 7 Integrates and measures the temperature of the gas mixture 2 at its flow through the gas mixture detection module 7 , The temperature sensor 8th However, it could also be located at another suitable location as long as it provides its meaningful readings to the gas mixture detection module 7 can transmit.

The pressure sensor 9 serves to measure the pressure of the gas mixture 2 , It is the pressure of the gas mixture 2 who is in the gas tank 3 prevails. This pressure could thus be referred to as the saturation vapor pressure of the vaporous phase of the gas mixture 2 directly in the gas tank 3 be measured. However, the pressure can also be measured at another location where it is in the gas tank 3 prevailing pressure by the pressure place with the gas tank 3 connected is. In the present case, such a solution was chosen and the pressure is determined by means of the in the gas mixture detection module 7 integrated pressure sensor 9 during the flow of the liquid gas mixture 2 through the gas mixture detection module 7 measured.

The gas mixture detection module 7 So is a measured value pair of the temperature and the pressure of the gas mixture 2 through the sensors 8th . 9 fed. In the gas mixture detection module 7 are different saturation vapor pressure curves 20 for different mixing ratios of the gas mixture 2 deposited and the gas mixture detection module 7 is so hardware and software equipped so that it due to the measured values and the saturation vapor pressure curves 20 the current mixing ratio of the gas mixture 2 can determine. How exactly this happens is further below with reference to the 4 . 6 . 8th and 10 described.

The calculated mixing ratio of the gas mixture 2 will now be over the electrical wires 14 the gas control unit 13 transmitted analog or digital. In the gas control unit 13 are in turn gas maps 21 for different mixing ratios of the gas mixture 2 saved.

Like the gas maps 21 look and the assignment to the saturation vapor pressure curves 20 will expire, will be described below.

Depending on the determined current mixing ratio of the gas mixture 2 are now through the gas control unit 13 the appropriate gas map 21 and the values to be applied in it. Depending on this, then the injection of the gas mixture takes place 2 through the injection valves 11 in the combustion chamber of the engine 19 so that proper combustion is ensured.

Control in defined time intervals

The gas mixture detection module 7 is preferably designed such that it determines the actual mixing ratio of the gas mixture 2 repeatedly performed at defined time intervals. These time intervals are after starting the engine 19 , so the measurements so several times with the engine running 19 be performed. The time interval is freely selectable per se, wherein it has been shown that a time interval of between approximately 20 seconds and 5 minutes, in particular between approximately 20 to 40 seconds and preferably of approximately 30 seconds, is advantageous. Through this repeatedly performed measurement and the corresponding control, there are various advantages, as will be further described below.

By the fact that at all a determination of the mixing ratio of the gas mixture 2 and a dependent control of the gas control device 13 is carried out initially at the beginning of the gas combustion operation - possibly even after a new refueling of the gas tank 3 - Ensures that regardless of the mixing ratio, a proper gas combustion process in the engine 19 he follows.

Due to the repeated measurements and controls during operation, temperature fluctuations are also taken into account, such as those due to the wind, the parking of the vehicle in the sun, the parking of the vehicle in a garage and the subsequent operation at minus temperatures. These temperature differences leading to a change in the density of the gas mixture are now determined by a corresponding selection of another gas map 21 through the gas control unit 13 considered in the sense of proper combustion.

Another significant advantage is that even the gasoline control unit, which is also permanently operated in gas combustion mode 16 is not unintentionally adjusted, as described in detail above.

2 shows a schematic view of a second exemplary embodiment of the new device 1 , In this case, unlike in 1 illustrated embodiment, not an injection system, but an injection system, and more specifically to an injection system for a direct injection. This embodiment has many with the embodiment according to 1 matching features, so that in order to avoid unnecessary repetition to the above-mentioned embodiments reference is made.

Because the device 1 not for injection, but for injection - ie for introducing the gas mixture 2 in liquid form into the combustion chamber of the engine 19 - Is formed, this has no evaporator / pressure regulator 10 , but, inter alia, a fuel pump 22 on. The fuel pump 22 is over the line 6 and a gas inlet 23 with a valve block 24 connected. The valve block 24 is again via lines 25 . 26 with a high pressure pump 27 connected. From the high pressure pump 27 leads a line 28 to the gasoline injection valves 18 , The petrol injection valves 18 also serve to inject the liquid gas in the gas combustion mode, so that they simultaneously gas injection valves 29 form. In other words, in addition to the gasoline injection valves 18 no separate injection valves required for the gas. The valve block 24 also has a gas return 30 on, over the liquid gas mixture 2 in the gas tank 3 is returned. Further recognizable are the gasoline flow 31 and the gasoline return 32 also with the valve block 24 are connected.

In this embodiment of the device 1 Thus, in a known manner, the high-pressure pump 27 and the gasoline injection valves 18 in gas mode for supplying the liquid gas mixture 2 in the combustion chamber of the engine 19 used.

In contrast to the embodiment of the device 1 according to 1 here are the sensors 8th . 9 outside the housing of the gas mixture detection module 7 arranged. The sensors 8th . 9 are via electrical lines 35 with the gas mixture detection module 7 connected.

3 shows another exemplary embodiment of the new device 1 , This is an injection system where the injection into the intake port is the engine 19 he follows. This embodiment has many with the embodiments according to 1 and 2 matching features, so that in order to avoid unnecessary repetition to the above-mentioned embodiments reference is made.

In this case, the fuel delivery pump 22 over the gas inlet 23 with the gas injection valves 29 connected. The pressure required for injection is via a pressure regulator 33 built, over a wire 34 with the gas injection valves 29 connected is. The gas return 30 then leads to the gas tank 3 back.

Also in this embodiment of the device 1 are the temperature sensor 8th and the pressure sensor 9 outside the gas mixture detection module 7 arranged and via electrical lines 35 associated with this.

Depending on the current mixing ratio of the gas mixture ( 2 ), the gas control unit ( 13 ) for ensuring optimum combustion in the gas combustion operation without adversely affecting the gasoline combustion operation.

4 shows a saturation vapor pressure curve 20 for a certain mixing ratio of a certain gas mixture 2 , In the present case, the gas mixture 2 LPG, ie a mixture of propane and butane.

In 4 is a gas mixture 2 with a proportion of propane of 20% and a proportion of butane of 80% (each in volume percent). The others 6 . 8th and 10 show corresponding saturation vapor pressure curves 20 for other mixing ratios of the gas mixture 2 , It is understood that corresponding saturation vapor pressure curves 20 for further mixing ratios and also for gas mixtures consisting of other gases 2 can be specified.

In the saturation vapor pressure curves 20 is indicated on the vertical axis of the saturation vapor pressure in millibars (mbar). The horizontal axis shows the temperature in degrees Celsius (° C). Such as a comparison of 4 With 10 shows, liquefied petroleum gas with a mixing ratio of 20% propane and 80% butane at a temperature of 0 ° C, a pressure of slightly less than 2000 mbar (ie 2 bar). At a mixing ratio of 85% propane and 15% butane, the pressure at the temperature of 0 ° C is already slightly more than 4000 mbar (ie 4 bar) and thus more than twice. By using a plurality and in particular a plurality of such saturated vapor pressure curves 20 thus allows the mixing ratio of the gas mixture 2 based on the respective measured value pair of temperature and pressure.

In the 5 . 7 . 9 and 11 are now assigned to the respective mixture ratio gas maps 21 shown. In the gas fields 21 is the injection time in milliseconds (ms) and the speed of the motor 19 in revolutions per minute (rpm). For example, the injection time of 3.00 ms at a speed of 4000 rpm is assigned the numerical value "111". This numerical value "111" represents the injection quantity and represents the amount of gas that is selectively supplied to the individual engine combustion chambers.

According to the invention is thus dependent on the determined mixing ratio of the gas mixture 2 each the appropriate gas map 21 in the gas control unit 13 selected and thereby the injection or injection of the gas mixture 2 regulated to achieve optimal combustion.

LIST OF REFERENCE NUMBERS

1

contraption

2

mixture of gases

3

gas tank

4

Multiventil

5

swimmer

6

management

7

Gas mixture recognition module

8th

temperature sensor

9

pressure sensor

10

Evaporator / pressure regulator

11

gas injection

12

Electrical line

13

Gas control device

14

Electrical line

15

Electrical line

16

Gasoline controller

17

Electrical line

18

Fuel injectors

19

engine

20

Saturation vapor pressure curve

21

Gas map

22

Fuel pump

23

gas supply

24

manifold

25

management

26

management

27

high pressure pump

28

management

29

Gas injection valve

30

Gas return

31

gasoline supply

32

Gasoline return

33

pressure regulator

34

management

35

Electrical line

36

Electrical line

Claims (9)

Mixed gas detection module ( 7 ) for determining the mixing ratio of a liquid gas mixture ( 2 ) of a first liquid gas and a second liquid gas, wherein the gas mixture ( 2 ) Is liquefied petroleum gas (LPG) and has propane and butane, the gas mixture ( 2 ) for combustion in an engine ( 19 ) of a motor vehicle with a gasoline control unit ( 16 ) and a gas control device ( 13 ) and the engine ( 19 ) from a gas tank ( 3 ) is supplied to the motor vehicle, wherein the gas mixture detection module ( 7 ) for receiving a value of the pressure of the gas mixture ( 2 ) in the gas tank ( 3 ) and the temperature of the liquid gas mixture ( 2 ) is formed and over electric lines ( 14 ) with the gas control unit ( 13 ), and wherein the mixed gas detection module ( 7 ) for multiple determination of the actual mixing ratio of the gas mixture ( 2 by determining the proportions of propane and butane after starting the engine ( 19 ) with the engine running ( 19 ) by comparing the measured values of the temperature and the pressure of the gas mixture ( 2 ) with the corresponding values in saturation vapor pressure curves ( 20 ) for different mixing ratios of the gas mixture ( 2 ) and wherein the gas control device ( 13 ) the gas injection or gas injection times of the engine ( 19 ) depending on the actual mixing ratio of the gas mixture ( 2 ) so that the fuel control unit ( 16 ) is not adjusted. Mixed gas detection module ( 7 ) according to claim 1, characterized in that the gas mixture detection module ( 7 ) is designed such that it determines the determination of the current mixing ratio of the gas mixture ( 2 ) repeatedly at defined time intervals. Mixed gas detection module ( 7 ) according to claim 2, characterized in that the time interval is between 5 seconds and 5 minutes. Contraption ( 1 ) for determining the mixing ratio of a liquid gas mixture ( 2 ) of a first liquid gas and a second liquid gas, wherein the gas mixture ( 2 ) Is liquefied petroleum gas (LPG) and has propane and butane, the gas mixture ( 2 ) for combustion in an engine ( 19 ) of a motor vehicle with a gasoline control unit ( 16 ) and a gas control device ( 13 ) and from a gas tank ( 3 ) of the motor vehicle, with a temperature sensor ( 8th ) for measuring the temperature of the liquid gas mixture ( 2 ), a pressure sensor ( 9 ) for measuring the pressure of the gas mixture ( 2 ) in the gas tank ( 3 ), and one with the temperature sensor ( 8th ) and the pressure sensor ( 9 ) connected gas mixture detection module ( 7 ) according to at least one of claims 1 to 3. Method for controlling a mixture with a liquid gas mixture ( 2 ) powered engine ( 19 ) of a motor vehicle with a gasoline control unit ( 16 ) and a gas control device ( 13 ), wherein the liquid gas mixture ( 2 ) comprises a first liquid gas and a second liquid gas, wherein the gas mixture ( 2 ) Is LPG and comprises propane and butane, comprising the steps of measuring the temperature of the liquid gas mixture ( 2 ) with a temperature sensor ( 8th ), Measuring the pressure of the gas in a gas tank ( 3 ) of the motor vehicle gas mixture ( 2 ) with a pressure sensor ( 9 ), Transmitting the measured values of the temperature and the pressure of the gas mixture ( 2 ) to a gas mixture detection module ( 7 ), multiple determination of the mixing ratio of the gas mixture ( 2 ) with the gas mixture detection module ( 7 ) after starting the engine ( 19 ) with the engine running ( 19 ) in the sense of determining the proportions of propane and butane by comparing the measured values of temperature and pressure of the gas mixture ( 2 ) with the corresponding values in saturation vapor pressure curves ( 20 ) for different mixing ratios of the gas mixture ( 2 ), and rules of the gas control unit ( 13 ) for adaptation to the current mixing ratio of the gas mixture ( 2 ), wherein the gas control device ( 13 ) a gas injection field containing gas injection or gas injection times ( 21 ), wherein the gas injection or gas injection times in dependence on the current mixing ratio of the gas mixture ( 2 ) are adjusted so that the gasoline control unit ( 16 ) is not adjusted. A method according to claim 5, characterized in that the determination of the current mixing ratio of the gas mixture ( 2 ) is repeatedly performed at defined time intervals. A method according to claim 6, characterized in that the time interval is between 5 seconds and 5 minutes. Method according to at least one of claims 5 to 7, characterized in that the liquid gas mixture ( 2 ) and vaporized as gas in the engine ( 19 ) is blown. Method according to at least one of claims 5 to 7, characterized in that the gas mixture ( 2 ) in liquid form in the engine ( 19 ) is injected.

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