DE4131626A1 - Fuel injection control for low emission IC engine - uses detected fuel ratio to control fuel injection into combustion space - Google Patents

Abstract

The fuel injection control has a fuel injection device for injection of fuel and at least one further fluid, the mixture ratio being monitored for controlling the injection into the combustion space. The mixture ratio may be detected directly, or indirectly by separate measurement of the quantity of fuel and the quantity of the further fluid supplied to the injection device. Pref. the fuel injection device uses magnetic valves with an injection signal (E2) generated from a calculated parameter (P2), with compensation of high or lower heating valves of the fuel. ADVANTAGE - Ensure optimum combustion.

Description

The invention relates to a method for controlling the Fuel injection of an internal combustion engine according to the Preamble of claim 1.

Methods are known in which in particular for Performance increase and to reduce exhaust emissions an internal combustion engine two different types of fuel with different calorific values. So is from DE 31 29 726 known that - starting from a Basic quantity of a first fuel type, the calorific value of which The calorific value requirement of the internal combustion engine corresponds - that Quantity ratio of the types of fuel to be injected Hand determined the load state of the internal combustion engine becomes. On this basis, the injected Fuel quantities calculated for the two types of fuel and fuel injectors (solenoid valves) ent driven according to the previous calculations. However, this process is time consuming and does not result based on the determination of the quantitative ratios over the load state of the internal combustion engine to an imprecise type control of the fuel injector.

The invention has for its object a method for controlling the injection of an internal combustion engine specify, the internal combustion engine a fuel and at least one further liquid can be supplied and the mixing ratio of the fuel with the at least any liquid for optimal combustion can.

This task is accomplished through a method of controlling the Injection of an internal combustion engine, the internal combustion engine via at least one injection device Fuel and at least one other liquid for ver Burn supplied, solved that characterized is that a mixture ratio of fuel and liquid is determined and the injection into the Combustion chamber takes place and at least depending on the he average mixture ratio is controlled. It has it turned out that to comply with restrictive Ab gas regulations (for example in the USA) or the Use of internal combustion engines under certain Be conditions (such as in clean air areas or in Underground operation) the use of a fuel and at least one other liquid is advantageous. Around to ensure optimal combustion is invented according to a mixture ratio of fuel and liquid determined. After determining the mix the injection takes place in the at least a combustion chamber of the internal combustion engine, the one spraying at least depending on the determined Mi is controlled. It is possible that taking into account operating parameters of the focal engine (temperature, pressure and other operating and environmental parameters of the internal combustion engine (accelerator pedal position and other sizes) the mixing ratio of the  Any fuel with the at least one liquid can be. By controlling the injection based on the recorded sizes and the determined mixing ratio is an optimal combustion in the combustion chamber of the internal combustion engine machine guaranteed.

In a further development of the invention, the mixing ratio nis of fuel and liquid that the injection pre direction is fed, recorded directly. This direct Er Socket has the advantage that it is quickly an exact size (for example as an electrical signal) via the mixture relationship exists. This determined size then becomes Control of the injection used. Will fiction according to the fuel and liquid one The storage container is removed, so is the one with the liquid mixed fuel over a the mixing ratio direct-sensing sensor that sends an electrical signal emits, fed to the injector. This Vorge Hensweise with a corresponding device Advantage that the device is simple (a only storage tank for fuel and liquid) and filling the reservoir is easy. The Has use of a single storage container above it furthermore the advantage that the filling with fuel and Liquid can be arbitrary within wide limits. While the filling, it is conceivable that another, the Mi ratio of the sensor directly determining the filling monitored and an impermissible mixing ratio, that would make combustion impossible.

In a further development of the invention, one of the injection devices amount of fuel and flow liquid recorded separately and the mixing ratio indi determined directly from the recorded quantities. Becomes the force  substance and the liquid from separate storage containers taken, there are two ways to determine the Mixing ratio. On the one hand, the removed one Fuel and the removed liquid are mixed and via the Sen, which determines the mixture ratio directly sensor according to claim 2 of the injector. This has the advantage, for example, that one with a single fuel storage tank equipped firing engine light with a reservoir for one Liquid retrofitted and with the invention Procedure can be operated. On the other hand, there is Possibility that the ent of the separate storage containers taken fuel and liquid quantities over separate Sensors of the injector are supplied, wherein the mixing ratio indirectly from the recorded quantities is determined according to claim 3. In addition to retrofitting with a reservoir for a liquid is the Given advantage, the sensors used precisely on the To match fuel and the liquid used, so that the quantities supplied can be recorded precisely.

In a further development of the invention, the fuel and the Liquid is removed from separate storage containers and at least the quantities withdrawn via separate sensors fed two separate injectors. These The procedure has the advantage that the fuel and the Liquid independently of each other and especially time be injected into the combustion chamber differently can.

In a further embodiment of the invention, the Injection by timing the at least one Injector having solenoid valve, in which it are generally a common solenoid valve system  can. If the fuel and the liquid one removed from the storage container or from separate storage are removed and mixed, the on spraying into the combustion chamber through time control of a solenoid valve. The timing is carried out taking into account the sizes of the company and the environment sizes of the internal combustion engine and depending on it averaged mixing ratio by specifying on Start and end of spraying or by specifying Start and quantity of injection. Will the fuel and the Liquid is removed from separate storage containers and the withdrawn quantities via separate sensors two ge separate solenoid valves, the On occurs spraying by timing the two magnets valves that are analogous to the temporal An control of a single solenoid valve. Because of a different timing of the two In addition, the solenoid valve is initially the injection of fuel and then the injection of the rivers liquid or vice versa. Through this type of pre and main injection is dependent on the used Fuel or the liquid used precise timing for optimal combustion given the injection.

In a further development of the invention, the injection takes place by timing the fuel and the rivers liquid out at least as a pump-nozzle system made injector. Even with one System is the control of the injection at least in Ab dependence of the determined mixing ratio of Given fuel and liquid. As fuel comes for example diesel fuel, gas oil or petrol in Be dress. The liquid can be methanol,  Ethanol, rapeseed oil, water or other liquids (at act as ignition accelerators). The above Fuels and liquids are exemplary and stel len no restriction on the types of force used substance and liquid. Likewise, the invention Process both usable for a gasoline engine as well a diesel engine.

The present invention is based on the Drawing explained for example; in the drawing shows:

Fig. 1 shows an injection device having a sensor, the mixing ratio be determined,

Food holding FIG. 2 injector with two Vorratsbe,

Fig. 3 injector with two Magnetven tilen,

Fig. 4 time line charts showing a solenoid valve controlled injection,

Fig. 5 timeline diagrams to illustrate the solenoid valve-controlled injection of fuel and liquid.

In Fig. 1, a reservoir 1 is shown having a fuel and at least one further liquid contains (mixture) are mixed. Via a sensor 2 determining the mixture ratio, the mixture is supplied to an injection nozzle 4 via a solenoid valve 3 . To measure the mixture takes place via a time-dependent elec tric control of the solenoid valve 3 , which is described in more detail in Fig. 5. Furthermore, the injection device shown has an electronic control device 5 , with the electronic control device 5 being supplied with operating variables of the internal combustion engine and their environmental variables via sensor inputs 6 . As operating variables of the internal combustion engine, for example, speed, load, and pressures and temperatures, and ambient variables, for example, an ambient temperature or an ambient pressure are detected and supplied to the electronic control unit 5 . The detected quantities are supplied to the electronic control device 5 directly (for example in analog form) or converted by appropriate preprocessing (analog-digital conversion) and the electronic control device's then provided as data. The sensor 2 determining the mixing ratio is electrically connected to the electronic control device 5 and, for example in the form of an electrical voltage, provides a measure of the mixing ratio of fuel and liquid in the storage container 1 to the electronic control device 5 . From the detected quantities and the mixing ratio, the electronic control device 5 calculates a signal (injection signal) with which the solenoid valve 3 is controlled. The mixture is injected into the combustion chamber via the injection nozzle 4 . The reservoir 1 is also a sensor 7 for the mixture ratio in the tank zugeord net, the sensor 7 is also connected to the electronic control device 5 . The sensor 7 has the task of determining the mixing ratio, for example, during the filling process of the storage container 1 with fuel and liquid. If the mixing ratio reaches an inadmissible value during the filling process, this is detected by the sensor 7 and a signaling device 8 is activated via the electronic control device. In its simplest form, this can be, for example, a signal lamp that shows an operator the impermissible mixing ratio.

Fig. 2 shows an injector with two Vorratsbe containers. In addition to the components shown in FIG. 1 and provided with the same reference numbers, separate storage containers 1.1 for fuel and 1.2 for the further liquid are present in FIG. 2. The amount of fuel withdrawn from the reservoir 1.1 is determined by a sensor 2.1 and the amount of liquid withdrawn from the reservoir 1.2 by a sensor 2.2 . The sensors 2.1 and 2.2 are connected to the electronic control device 5 (sensor 2.2 via the connection marked VV). In a further embodiment of the invention, not shown, it is also conceivable that the fuel and the liquid are removed from the separate storage containers 1.1 and 1.2 , mixed and then supplied via the magnetic ratio sensor 3 via the solenoid valve 3 to the injection nozzle (according to claim 5 ). If the withdrawn quantities are determined by the two sensors 2.1 and 2.2 , the electronic control device 5 calculates the mixing ratio.

Fig. 3 shows an injector with two Magnetven valves. In addition to the 2 shown in Fig. 1 and Fig. And provided with the same reference numerals components of the reservoir 1.1 withdrawn fuel is led through the sensor via a solenoid valve 2.1 3.1 4.1 to an injection nozzle. In an analogous manner, the liquid removed from the storage container 1.2 is fed to an injection nozzle 4.2 via the sensor 2.2 and a solenoid valve 3.2 . On the basis of the sensor inputs 6 and the quantities taken from the sensors 2.2 and 2.3 (from which the mixing ratio is calculated), the solenoid valves 3.1 and 3.2 are actuated by the electronic control device 5 . In the time control, it is conceivable, for example, that fuel is injected before the injection of the liquid or vice versa. Other common elements of an injection device such as feed pump, filter or pressure regulator are omitted in FIGS . 1 to 3 to simplify the illustration.

Fig. 4 shows timing diagrams for illustration of a solenoid valve controlled injection. Starting from a signal shown in FIG. 4a (for example crankshaft signal which indicates the top dead center of a cylinder), a parameter shown in FIG. 4b is calculated from P1, in which operating variables and environmental variables of the internal combustion engine are taken into account. The parameter P1 is calculated in the electronic control device 5 . On the basis of the calculated parameter P1, an injection signal E1 shown in FIG. 4c is generated, with which a solenoid valve is controlled. The solenoid valve lift shown in FIG. 4d results from the injection signal E1, the start of delivery FB1 and the end of delivery being designated FE1. The index "1" refers to a cylinder and an associated solenoid valve of the injector of the internal combustion engine. The increment of the index represents the assignment of the procedure to each solenoid valve of the injection device of the internal combustion engine. For example, a parameter (P1, P2...) Is calculated for each solenoid valve and the corresponding injection signals are generated.

Fig. 5 shows time line diagrams to illustrate the magnetic valve-controlled injection of fuel and liquid. In an analogous procedure to Fig. 4, starting from a ter shown in Fig. 5a a signal parame P2 is, for example, calculated for the second cylinder, which is shown in Fig. 5b. The parameter P2 takes into account the operating variables and environmental variables of the internal combustion engine and the mixing ratio determined by sensor 2 (or 2.1 and 2.2). On the basis of the calculated parameter P2, an injection signal E2 is generated that takes the mixing ratio into account (FB2 and FE2) and is shown in FIG. 5c. This injection signal E2 is longer than the injection signal E1 shown in FIG. 4c, so that a heating value compensation takes place due to the injection of the mixture of fuel and liquid. A corresponding calculation of the parameter P2 compensates for a higher or lower calorific value, which is the case with the sole use of fuel (as shown for example in FIG. 4). When using an injection device with two solenoid valves, such as that shown in Fig. 3, it is conceivable that a parameter is calculated on the basis of a signal (crankshaft signal), on the basis of which a first injection signal for the solenoid valve 3.1 and a second Injection signal for the solenoid valve 3.2 is generated. Due to the timing of the generated injection signal (start and length of the injection signals), the injection of the liquid is then possible and then the injection of fuel or vice versa.

Claims (9)

1. A method for controlling the injection of an internal combustion engine, wherein the internal combustion engine via at least one injector, a fuel and at least one other liquid for combustion are supplied, characterized in that a mixture ratio of fuel and liquid is determined and the injection into the combustion chamber takes place and is controlled at least depending on the determined mixing ratio. 2. The method according to claim 1, characterized in that the mixing ratio of Fuel and liquid that the injector is fed, is detected directly. 3. The method according to claim 1, characterized in that one of the injector amount of fuel supplied and a lot of liquid separates and the mixing ratio indirectly is determined from the recorded quantities.   4. The method according to any one of the preceding claims, characterized in that the fuel and the rivers liquid from a storage container and the one Mixing ratio directly determining the sensor spraying device are supplied. 5. The method according to any one of the preceding claims, characterized in that the fuel and the rivers liquid removed from separate storage container, ver mixes and over the determining the mixture ratio Sensor of the injector are supplied. 6. The method according to any one of the preceding claims, characterized in that the fuel and the rivers liquid from separate storage containers and the withdrawn quantities via separate sensors of the injection device are fed. 7. The method according to any one of the preceding claims, characterized in that the fuel and the rivers liquid from separate storage containers and the withdrawn quantities via separate sensors at least two separate injectors are supplied. 8. The method according to any one of the preceding claims, characterized in that the injection by time Liche control of the at least one solenoid valve the injector. 9. The method according to any one of the preceding claims, characterized in that the injection by time Liche metering of the fuel and the liquid over an at least designed as a pump-nozzle system spraying device takes place.