DE3426514A1 - Device for the operation of an internal combustion engine exclusively with liquid gas - Google Patents

Abstract

A device for the operation of an internal combustion engine, especially a vehicle engine, exclusively with liquid gas provides for a shortened water circuit, which comprises an evaporator, a water heater and a circulating pump, and can be produced to start the engine at outdoor temperatures of less than 20 DEG C under the control of assigned thermostats, for preheating the evaporator to an operating temperature in order to permit starting of the engine directly in liquid gas operation, or in the event of failed starting, a renewed starting of the engine and thereby to render a double fuel supply for liquid gas on the one hand and petrol on the other superfluous, in addition also overcoming the problems resulting from failed starting in liquid gas operation, which otherwise render renewed starting of the engine in liquid gas operation impossible.

Description

description

The invention relates to a device for the

Operation of an internal combustion engine, in particular a Fahr-5

engine, exclusively with liquid gas, e.g. liquefied Petroleum gas or methane gas.

For operation with liquefied petroleum gas or methane gas equipped vehicles have known the disadvantage that the transferred into an evaporator in a gaseous state fuel, in particular at a Kühlwassertem-oeratur at about 0 ⁰ C, a strong cooling of the evaporator to approximately -15 causes up to -20 ^{0 C.} Starting the engine is extremely difficult, if not impossible at all.

This disadvantage is usually counteracted that operates the motor for starting with petrol, which is obviously only possible when the engine via a ² ^ dual fuel supply for gasoline and LPG has a turn on the other.

It is therefore common practice to feed the cold engine with gasoline during the start-up process and then switch to LPG mode when the cooling water temperature exceeds ^{HO 0 C.}

DAS switching from gasoline to LPG operation requires at ambient temperatures of about 0 ⁰ C a normally Warir.laufzeit of about 10 minutes, and at an outside temperature of about -20 ⁰ C a warm-up time of about one quarter of an hour.

At outside temperatures of about 30 to HO ⁰ C, on the other hand, there are no difficulties whatsoever with regard to starting directly in liquid gas operation, even in the case of an engine with a double fuel supply.

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Considerable difficulties can also arise if, after attempting to start the engine in liquid gas mode at a low temperature, the engine stops again for whatever reason and the battery is too weak or insufficiently charged to attempt another start. If the engine has already been running for about two or three minutes in such a case, an ice layer has formed around the evaporator *, which makes restarting the engine practically impossible.
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As long as the temperature of the evaporator is less than 0 ^° C., the gas, if it evaporates at all, precipitates on the walls of the evaporator and is thus liquefied again, so that starting the engine is impossible.

These difficulties are common to all operators of a dual fuel gasoline and LPG engine well known.

To remedy these difficulties, the Proposed pre-heating of the evaporator by means of battery-powered electrical heating resistors. this However, it requires a battery that is well charged at all times, otherwise it could be completely discharged, which leads to other easily imaginable difficulties.

One aim of the invention is to create a device of the type mentioned at the beginning in the form of a circulating pump, an evaporator and a water heater working with electrical resistance heating, shortened Water circuit in which not all of the cooling water circuit contains - water, but only the small amount in The amount of water contained in this water cycle is preheated to

QQ are required to enable the engine to be started in direct LPG mode at practically any outside temperature without the battery having to be excessively charged.

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In practical tests it has been shown that it is possible with a device of the type mentioned, even if the battery is not excessively heavily charged, to start the engine directly in liquid gas mode, i. ^v ;. thus without backgr ^: .: T to a supply with gasoline, so that the devices for the supply of gasoline can be omitted without disadvantages.

The following is an embodiment of the invention explained with reference to the drawing. Show it:

1 shows a schematic representation of a cooling water circuit in normal operation,

2 shows a schematic representation of the cooling water circuit in the cold start state and

Fig. 3 is a schematic representation of the electrical switching devices for the operation of the invention Contraption.

A in Fig. 1 and 2 shown cooling water circulation "includes an evaporator 1, a water heater 2 and a circulation pump 3 comprehensive condensed water circuit, manufactured automatically weleher at a temperature of less than 20 ⁰ C and at higher temperatures is automatically resolvable.

The cooling water circuit or the shortened water circuit also includes three solenoid valves 4, 5 and 6 and three Thermostats 7, 8 and 9.

During normal engine operation, i.e. when the engine is warm, the two solenoid valves 4 and 6 are open and the solenoid valve 5 is closed. To start the cold engine are on the other hand, the solenoid valves 4 and 6 are closed and the solenoid valve 5 open in order in this way to dispose of the evaporator 1, the water heater 2 and the circulating pump 3

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to establish a shortened water cycle. The three thermostats serve to facilitate the manufacture and dissolution of the shortened To control the water cycle.

As can be seen in Fig. 3, an ignition lock 10 are a Main switch 11, a red, a green and a yellow indicator lamp 12, 13 and 14 and a switch 15 on Dashboard of a vehicle arranged while the thermostats 7, 8 and 9, the solenoid valves 4, 5 and 6, the Circulation pump 3, the water heater 2 and the associated relays 16 and 17 are arranged near the engine.

The device described works as follows: In the normal operation shown in Fig. 1 at a sufficiently high cooling water temperature, the _{water coming from the cooler in the direction of the arrow F 1} flows through the open solenoid valve 4, the evaporator 1 and the solenoid valve 6 in order to move in the direction of the arrow F ₂ Flow back cooler. In this case, the solenoid valve 5 is closed in normal operation, and the water heater 2 and the circulating pump 3 are not flowed through by the water.

In the operating state shown in Fig. 2 with a cooling water temperature of less than 20 ⁰ C, the Ma -etventile 4 and 6 are closed and the solenoid valve 5 open, so that the parts belonging to the device described are decoupled from the cooling water circuit.

In this operating state, a reduced amount of water is over the evaporator 1, the water heater 2 and the circulation pump 3 comprehensive, closed water circuit ", as indicated by corresponding arrows in Fig. 2. This leads to a rapid heating of this small amount of water, regardless of the amount of water now via the open Ma ^ / t valve 5 running cooling water circuit.

The consumption of electrical energy by the water heater 2 is relatively low and corresponds roughly to that of the disk

heating on the rear window of a motor vehicle, so that the device works safely even when the engine is at a standstill. ;

. Effected in a cold engine, and an outside temperature of less than 20 ⁰ C, the Betätigung.des ignition to ahead of the starting position of the operating position, the closing of the solenoid valves 4 and 6 and the opening of the solenoid valve 5. Thus the state shown in Fig. 2 is given _T in which a small amount of water is circulated through the shortened water circuit comprising the evaporator t, the water heater 2 and the circulating pump 3. During this phase, the water heater 2 heats this small amount of water to a temperature of more than 20 ⁰ C, which is indicated by the lighting of the green indicator lamp 13 controlled by the thermostat 9 on the dashboard lights up and the engine starter motor is switched on.

After the starting of the motor and the actuation of the switch 15 shown in Fig. 2 condensed water circuit is maintained until the cooling water temperature at least 20 ⁰ C was reached, whereupon the thermostat 7 the restoration of the in F.ig. 1 causes the normal state of the cooling water circuit shown.

If the water temperature in the shortened water circuit rises above 30 ^° C., then the thermostat 8 interrupts the power supply to the water heater 2 in order to limit the discharge of the battery.

If the engine stops for whatever reason as long as the cooling water temperature is still less than 20 ^° C., the processes described above are repeated, ie by actuating the switch 15, the shortened water circuit shown in FIG. 1 is restored.

At a cooling water temperature of 20 ⁰ C or above

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The starting of the engine normally takes place in the state of the cooling water circuit shown in FIG. 1, ie without power feeding the water heater 2 from the battery.
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As can be seen from the above description, it enables the use of a with low power consumption of the battery powered Wassererhi "3ers for heating one contained in a closed water circuit that does not include the radiator of the motor vehicle Amount of water to start the engine directly in LPG mode, i.e. without gasoline supply, whereby the starting process can be repeated several times in the event of a false start without the risk of the evaporator is excessively cooled, making it impossible to start.

The device according to the invention thus advantageously obviates the use or recourse to the Fuel supply for starting the internal combustion engine.

In any case, it is only advisable to monitor the state of charge of the battery so that the engine is at a standstill the Stromspeisugn of the water heater 2 is guaranteed, even if its power consumption is also very low and, as already indicated, roughly corresponds to that of a heating panel.

The use of the device according to the invention offers the obvious advantages that in the case of a Failure to start the engine in LPG mode prevents the evaporator from cooling down excessively cold engine in liquid gas operation by briefly preheating a small amount of water in a closed Makes the water cycle possible in the first place and in this way eliminates one of the major difficulties which, as is well known, arise when an internal combustion engine is operated with liquid gas.

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Claims (3)

Claims Device for operating an internal combustion engine, in particular a vehicle engine, exclusively with liquid gas, characterized in that at a cooling water temperature of less than 20 ⁰ G through 30 corresponding actuation a gas vaporizer (1) a Water heater (2) and a circulation pump (3) more comprehensive, a shortened water cycle containing a limited amount of water can be produced, in which the water heater (2) for rapid heating of the evaporator (1) to one for 35 Starting the engine on gas operation and to compensate for the unavoidable cooling of the evaporator (1) if the engine stops after an attempt to start in gas mode sufficient temperature with low power consumption 2
powered by the vehicle's battery. 34265M 2. Apparatus according to claim 1, characterized in that the shortened water ^{circuit when reaching and exceeding a temperature of 20 0} C in the cooling water circuit by means of a series of through to the reflux line of the cooler, the outlet line of the water heater (2) and the supply line of the evaporator (1) arranged thermostat (7, 8 or 9) controlled solenoid 1.0 valves (4, 5 or 6) can be automatically connected to the cooling water circuit and that the shortened water circuit in the event of a cooling of the evaporator (1) caused by a false start If the water temperature drops below 20 ⁰ C, it can be automatically restored. 3. Apparatus according to claim 1 and / or 2, characterized in that a number of indicator lights (12, 13, 14), a main switch (11) and a changeover switch (15) first the ignition lock (10) of the vehicle are arranged on the dashboard of the same, while the other parts, namely the circulation pump (3), the water heater (2) the solenoid valves (4, 5, 6), the associated Thermostats (7, 8, 9) and the supply of the circulating pump and the water heater serving relay (16 or 17) in the or are arranged on the engine compartment so that they are to be preheated for starting the engine at low temperatures The amount of water is limited to a minimum.