DE2941771A1 - WATER-COOLED FUEL MACHINE OPERATED WITH ALCOHOL AS A FUEL - Google Patents

Description

Daimler-Benz Aktiengesellschaft Daim 12 8ft

Stuttgart-Untertürkheim October 12, 1979

Operated with alcohol as the operating fuel water-cooled internal combustion engine

The invention relates to a fuel with alcohol operated water-cooled internal combustion engine, in particular for commercial vehicles, according to the preamble of claim 1.

They are water-cooled and run with alcohol as the operating fuel Internal combustion engines, especially for commercial vehicles, known. For faster heating of the fuel vaporizer, the cooling water circuit is on the one hand the internal combustion engine is provided, which through a thermostatic valve via a heat exchanger for Used to heat the fuel vaporizer. The water of the cooling water circuit flowing out of the evaporator flows back to the water pump of the internal combustion engine and is when the operating temperature is exceeded diverted through a vehicle radiator via a thermostat.

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For faster heating of the fuel evaporator is this cooling water circuit on the other hand by a further provided with a pump, from an exhaust gas heat exchanger heated water cycle supported. The cooling water circuit and the further water circuit are via a Thermostatic valve interconnected. When the internal combustion engine is at operating temperature, the further heated water circuit is switched off via a separate thermostat. The required heat of vaporization for the fuel is then exclusively the cooling water circuit of the operating temperature Internal combustion engine taken.

Since the heating of the fuel vaporizer, in particular at very cold ambient temperatures, is time-consuming, the object of the invention is to use suitable Measures for starting at ambient temperatures below the operating temperature of the evaporator do not heat up the fuel vaporizer to be able to.

This task is indicated by the characterizing part of the claim 1 solved.

These are suitable as starting fuels under normal conditions gaseous fuels such as methane (natural gas), propane, etc. separate fuel tank carried and via a dependent from the starter of the internal combustion engine and the temperature at the cooling water outlet of the evaporator via a thermostat, which has a temperature-dependent reduction and Switching valve in the line for the starting fuel controls, and optionally starting fuel the upper part of the Evaporator supplies. As a result, the cold internal combustion engine

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machine using the one provided at the evaporator outlet Pressure control valve can be started immediately without any preheating of the internal combustion engine.

With the start of the cold internal combustion engine is at the same time an additional circulation pump put into operation, so that exhaust gas heat exchanger and fuel evaporator from Water flows through it.

To the time for the operation of the internal combustion engine with Shorten starting fuel - although the internal combustion engine itself has not yet reached its operating temperature - can the internal combustion engine in an embodiment of the invention be carried out according to claim 2.

By acted upon by the exhaust gases of the internal combustion engine Heat exchanger in front of the fuel evaporator is arranged, there is an intensive and short-term heating via a short-circuit water circuit with a circulating pump of the fuel vaporizer, which then after reaching the operating temperature by appropriate thermostat changeover tvalves to the cooling water temperature or to a constant temperature for the operation of the internal combustion engine optimally defined temperature level is maintained. The reducing and switching valve is controlled by the one at the outlet of the evaporator provided thermostat controlled such that when a defined temperature is reached for the fuel he vaporizes the feed line for the starting fuel is interrupted.

Finally, the drive of the circulating pump can continue to operate as in claim 3 for the short-circuit water circuit in the Way also be coupled with a thermostat.

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With reference to an embodiment shown in the drawing The invention will be explained in more detail.

The figure shows a circuit diagram of an alcohol gas engine according to the invention.

In the circuit diagram for an alcohol gas engine shown in the figure, the liquid fuel arrives from a fuel tank 1, conveyed by means of a fuel pump 2, through a fuel supply line 3 into a fuel evaporator k. An overflow valve 5 arranged between fuel pump 2 and fuel evaporator k allows excess fuel to flow back into fuel tank 1 via line 6.

Evaporated, that is to say gaseous, arrives from the fuel evaporator 4 Fuel, via a pipe system 7 to the air / gas mixer 8 and via an intake port 9 »with a throttle valve 10, to the cylinders of an internal combustion engine 11.

The cooling water circuit 12 of the internal combustion engine 11, with its own water pump 13, can in a manner known per se by means of a thermostat 14 depending on the temperature via a Vehicle radiator 15 are switched.

In the cooling water circuit 12, 12 'a thermostatic valve 16 is also provided, which is designed as a 3/2-way valve and can switch the cooling water circuit of the internal combustion engine 11 in such a way that the cooling water is conducted via a pipe 17 to an exhaust gas heat exchanger 18, which the heat exchanger 19 of the evaporator k is connected upstream. The cooling water circuit 12, 17 is connected back to the water pump 13 via a bypass line 20 going out from the heat exchanger 19.

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In addition to the cooling water circuit 12, 17, 20, a further water circuit 21, 20, 2k with its own circulating pump 23 is provided, the water circuit of which flows into the pipe 17 via the line 2 "! And is also passed via the exhaust gas heat exchanger 18 and the heat exchanger 19 of the evaporator k flows through. the connection is made to the circulating pump 23, and thus the water circuit 21 is closed by an outgoing line 20 from the branch line 2k.

For the cold start of the internal combustion engine 11, a container 25 with starting fuel, such as methane (natural gas), propane, etc. is provided, which is gaseous under prevailing normal pressure and temperature conditions. This fuel tank 25 is connected in a line 27 directly to the upper part of the evaporator k via an interposed reducing and switching valve 26. The cold internal combustion engine 11 can open the line 27 by controlling a thermostat 29 arranged on the flow side at the outlet of the evaporator k , so that the starting fuel is supplied to the upper part of the evaporator k and the internal combustion engine can be started immediately, i.e. without preheating time.

The starting fuel of the internal combustion engine 11 is switched on or off via a reducing and switching valve 26 as a function of the temperature of the thermostat 29 provided at the cooling water outlet from the evaporator k.

A temperature sensor 30 is provided in the pipeline 17 which, when the operating temperature of the internal combustion engine 11 is reached, switches off the circulating pump 23 and thus stops the water circuit 21, 20, 2k .

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L e r s e i t e

Claims (2)

Daimler-Benz Aktiengesellschaft Daim 12 815/4 Stuttgart-Untertürkheim October 12, 1979 Expectations 1 / Water-cooled ones operated with alcohol as the operating fuel Internal combustion engine, in particular for commercial vehicles, with a thermostat-controlled cooling water circuit for the internal combustion engine, containing a water pump and switching valves, with one of the cooling water circuit heatable evaporator for the fuel, characterized in that for starting the internal combustion engine (11) from temperatures below the operating temperature in addition to the fuel tank receiving the operating fuel (1) Another fuel tank (25) is provided, which is connected to the fuel supply of the internal combustion engine (11) as an alternative to the operating fuel can be connected via a reducing and switching valve (26), and that at the outlet of the evaporator (4) a water temperature determining thermostat (29) is arranged, which at least indirectly the reducing and switching valve (26) actuated in such a way that when the cooling water is at operating temperature, the operating fuel is switched on and at a lower temperature the starting fuel. -Z- 13 0 018/0139 - 2 - Daim 12 815/4 2. Internal combustion engine according to claim 1, characterized in that within the cooling water circuit (12) in the flow direction upstream of the evaporator (4) a heat-transferable exhaust gas heat exchanger (18) is provided that the evaporator (4) and the exhaust gas heat exchanger (18) can be short-circuited within the water circuit (21, 20, 24) by a branch line (24) branching off in the direction of flow behind the thermostat (29), in which branch line (24) a separate circulating pump (23) that can be driven Exhaust heating for the water circuit is arranged that within the cooling water circuit (12) also a short-circuit line (12 ') a thermostatic valve (16) is provided for switching the short-circuit line (12') on or off and that the cooling water circuit (12) depending on Position of the thermostatic valve ~ (16) via the pipe (17) to the exhaust gas heat exchanger (18) and via the heat exchanger (19) of the evaporator (4 ) and via the line (20) back to the water pump (13) of the internal combustion engine (11). 3 · Internal combustion engine according to claim 2, characterized in that the drive of the circulating pump (23) for the branch line (24) in terms of effect in the manner with the thermostat (30) in the line (17) is coupled that when the thermostatic valve (16) is open line (17) and thus sufficient Temperature at the thermostat (30), the circulation pump (23) is stopped and vice versa. 130018/0139