DE19828143C1 - Method of pre-heating internal combustion engine uses variable choke resistance line in parallel with bypass valve to enable choked flow through latent heat store for higher coolant temp. - Google Patents

Abstract

The method involves passing coolant through a latent heat store (L) for higher coolant temp. and bypassing it for lower coolant temp. A circulation pump (P) is switched on before starting the engine to pre-heat the engine using the heat in the latent heat store. A connecting line (3) with a variable choke resistance is connected in parallel with a bypass valve (905w) to enable a choked flow through the latent heat store for a higher coolant temp. or closed bypass valve, so that the residual or greater part of the coolant is fed via a bypass line (2) and non-return valve together with the coolant passing through the latent heat store back into the coolant circuit.

Description

The invention relates to a method for preheating a burner Motor according to the preamble of claim 1.

Such a method is already in DE 197 23 230 A1 by a device for simultaneous preheating a mo Gate catalyst that cools automatically in the event of overheating is described.

In addition to the 197 23 230 A1, one for heat transfer supply from a latent heat storage to the internal combustion engine see pump according to DE 197 58 472 A1 taken out of operation, once the engine has turned up to a certain starting temperature is heated, so that after starting the engine only one engine's own pump for the cooling water circulation, whereby a Re Lais is provided, which ensures that the burner one for the system provided auxiliary heating when preheating the Insas only when the vehicle is stationary to the auxiliary heater pump is put into operation when the Cooling water temperature in the latent heat storage to a value that has dropped slightly above the phase transition temperature of the heat storage medium contained in the memory.

A disadvantage of an embodiment according to DE 197 58 472 A1 still that the cooling water after reaching the for the engine provided initial temperature with the engine running by the engine's pump entirely through the latent heat accumulator is pumped through to heat it up again, whereby the Reaching the engine operating temperature is delayed unnecessarily.

Furthermore, from DE 195 35 027 A1 according to FIG. 2, a method for preheating an internal combustion engine 10 by means of a controllable ren circulation pump 24 built into the cooling water circuit 22 of the engine is known, which increasingly uses a three-way valve 36 to supply the cooling water with a latent heat storage device 34 pumped through until a housed in a controller 64 , the temperature before and after the heat storage in the cooling water circuit comparative comparison circuit after discharging the heat storage tank, the valve 36 so that the cooling water then after starting the engine by an engine pump 20 on Heat accumulator is pumped back to the engine.

The cooling water is then after reaching a certain, achieved by the heat output of the engine cooling water temperature via the three-way valve 36 with increasing temperature upstream of the heat accumulator again through the heat accumulator to recharge it, but this has the disadvantage that then the flow of Heat storage is reduced with decreasing cooling water temperature, so that a heat output from the memory to the cooling water circuit is reduced instead of increased if, for example, the built-in cooler circuit 14 cooler 12 increases its cooling capacity at increased driving speed and relatively low engine speed or low heat output of the engine and thereby causes a drop in the temperature of the cooling water. The heating plays less of a role here, since it is automatically reduced at higher driving speeds and concentration and replaced by better circulation, which is why racing drivers lose a few kilos in a race due to excessive sweating (running would be healthier).

Proceeding from this, the object of the invention is that Reaching the engine operating temperature compared to DE 197 58 472 A1 to speed up and recharge the heat chers to delay, the flow of the heat storage at running engine in contrast to DE 195 35 027 A1 after reaching a certain cooling water temperature with increasing cooling water reduced or increased with decreasing temperature is, so that the heat accumulator at a temperature drop Heat transfer to the cooling water circuit increased and so for one provides some balance.

This problem is solved in that parallel to one here additionally provided, in front of the heat storage in the cooling water circuit built-in thermostatically controlled bypass valve a connecting line with a thermostatically controlled Throttle valve is arranged to the latent heat storage delayed starting of the engine via the throttle load, the throttle the flow through the heat accumulator with increasing engine operating time or engine temperature of egg a certain maximum value to a certain minimum value reduced, so that the flow of the heat accumulator after a full load of the same to a minimum  is and the heat accumulator with a reduction in the engine temperature temperature increasingly releases heat to the cooling water circuit, in which the throttle then the flow through the heat accumulator taking increased.

In a preferred embodiment, the connecting line with the throttle in the engine compartment and the throttle so trained that their passage cross-section is thermostatic controlled with increasing room temperature from a certain one Maximum value reduced to a certain minimum value or with decreasing room temperature increased again.

This version has the advantage that the heat is given off by the heat memory to the cooling water circuit at one via cooling caused drop in temperature of the cooling water increases more quickly, such as if the throttle decreases its passage cross section Engine temperature increased because the room temperature in the engine compartment through the cooling air, through the two cooling provided here penetrates into the engine compartment, with an increase in Driving speed drops faster than the engine temperature, so that the throttle a temperature from the heat accumulator the cooling water is delayed as far as possible before driving speed or the flow of cooling water through the Cooler through their bypass valve at another tempe waste is reduced again to the cooling water temperature to increase again and to recharge the heat storage.

The heating of the latent heat storage by the heat dissipation of the Motors is here in contrast to DE 197 58 472 A1 by an Latent heat storage bypass line by the here additionally provided bypass valve is branched and from the the connecting line leading to the latent heat storage with the Throttle is branched, more or less delayed, the Saving fuel by accelerating the engine operating temperature compared to the fuel consumption by the Auxiliary heating for reheating the heat storage at Mon Gate standstill with an increasingly longer engine operating time ten is getting bigger.

Only with predominantly short operating times and long periods of silence Downtimes of the engine (trips by directors and managers Employees to their representative office, customer service rides  in the city area, housewife trips etc.) is an additional consumption given by the parking heater, but by a smaller one Engine wear and oil consumption are weighed again and the can also be equalized by adapting itself to this cycle reducing amount of cooling water through the heat accumulator conducts, so that the same at short engine operating times but without adversely affecting the engine warm-up phase, somewhat more heated up by the heat given off by the engine becomes.

Refinements of the invention are the subject of back-related Subclaims. In summary it shows:

Fig. 1 shows a control system for the cooling water circuit running an internal combustion engine M, which is heated here to a certain output temperature, which is indicated by the lighting of a signal lamp S.

Via a relay d ₁ , which is supplied with current together with the signal lamp via a thermal switch T ₁ , the power supply to a pump P, which transfers the heat stored in the latent heat accumulator L to the motor during preheating of the motor, is interrupted and the motor is started here via a key position 1 of the ignition lock I, so that the engine's own pump P _M ensures the cooling water circulation.

Via the relay d ₁ , the power supply to a blower BL 'with an attached electric heater is also interrupted, so that the preheating of the engine also ends the preheating of a catalytic converter K, which in the event of overheating by starting up the blower BL' via a in the catalytic converter used thermal switch T ₃ and a normally open contact is cooled by a relay d ₂ while a signal lamp S _{K is} lit. With the signal lamp S _K , a buzzer (not shown here) is also brought to hum.

For the preheating of the passenger compartment of a vehicle when the vehicle is at a standstill, a thermostat H _{St is} provided which is set to a specific temperature and activated in a key position 3 of the ignition lock I, the blower BL of a heater R _H , and the pump P _{St of} an auxiliary heater ST is put into operation, whereby the burner of the auxiliary heater is only put into operation via a temperature controller T L used in the latent heat store _L and a relay d when the cooling water temperature in the store has dropped to a value slightly above the phase transition temperature of the Storage ent contained heat storage medium is.

During the automatic heating of the latent heat store in a key position 3 of the ignition lock I, the pump and the burner of the auxiliary heater are supplied with current via the temperature controller T _L and the relay d, so that the engine with simultaneous preheating of the catalyst even after short operating times and longer downtimes is always preheatable to a certain output temperature, whereby an emission of pollutants is almost prevented immediately after starting the engine or the amounts of pollutants are barely measurable if the catalyst works and is not overheated.

For the heating of the passenger compartment while driving, a thermostat H _{Dr is} provided, which is set to a certain temperature in the key position 2 shown in the ignition lock ses I and is automatically activated when the temperature falls below this temperature, only the blower BL of the radiator R _H into operation , wherein the fan is started in the event of overheating of the cooling water via a thermal switch T ₂ used in the radiator at an increased speed.

According to the invention, a bypass valve 905 w without ( w ithout) additional electromagnetic control ( FIG. 4) is installed directly in front of the latent heat store L in the cooling water circuit, the bypass line 2 branching off from this valve and past the latent heat store not being branched off laterally from the valve here , as is provided in the bypass valve 905 i with (i nclusive) electromagnetic auxiliary control in the bypass of the cooler R _C, but branches off from the underside of the valve abge.

However, the connection for the supply line to the valve is the same, so that the cooling water on the lower outside of the Venti les flows into the bypass valve 905 w ( Fig. 4).

Until the temperature provided for the engine M is reached, the cooling water is in the lower end position of the valve body housed in the valve body by means of the pump P through the engine and the bypass valve 905 w through a line 1 branched off from the valve through the latent heat accumulator L and the radiator R _{H is} pumped through into the bypass valve 905 i, from which the cooling water then flows back to the pump P via a bypass line which branches off from this valve and leads past the coolers R _C.

After starting the engine via key position 1 of the ignition lock I, the engine's own pump P _M then ensures the circulation of the cooling water, the temperature of which continues to rise due to the additional heat given off by the engine.

At a cooling water temperature that is slightly higher than the starting temperature provided for starting the engine, the valve body housed in the bypass valve 905 w is pushed upwards ( FIG. 4), so that the cooling water is largely branched off from the valve at the bottom, bypassing the latent heat storage bypass line 2 and a check valve is fed into a supply line 5 to the radiator R _H , while the smaller part of the cooling water is branched by a bypass line 2, the flow cross section of the connecting line 3 , and the line branched from the valve 1 is fed through the latent heat store through a supply line 4 into the supply line 5 to the radiator.

The between the heat storage bypass line 2 and the branched from the bypass valve supply line 1 to the heat store parallel to the bypass valve arranged connecting line 3 is housed in the engine compartment ( Fig. 3) and has a thermostatically controlled throttle valve, the passage cross section with increasing engine operating time or Motor temperature, but preferably with increasing room temperature changed from a maximum flow cross-section to a minimum flow cross-section, so that the flow of the latent heat accumulator is increased with a reduction in the motor or room temperature via the throttle valve, which then also the heat dissipation of the Heat accumulator to the cooling water circuit increases when the temperature of the cooling water drops via the two coolers R _C due to an increased driving speed.

The calculation of the maximum passage cross section of the throttle, through which the warm-up phase of the engine is not adversely affected and the minimum passage cross-section over which the tem temperature in the heat accumulator more or less delays the increase menden cooling water temperature is known per se.  

Fig. 2 shows for the most part in the storage space in front of the heckseiti gene drive space of a motor vehicle housed components of the control system provided for the cooling water circuit of the engine, the thermostatically controlled bypass valve 905 w built into the cooling water circuit here, as well as the pump P for the preheating of the engine and an expansion tank CO provided for the cooling water circuit, together with the thermal switch T ₁ and the throttling connecting line 3 to the latent heat accumulator are accommodated in the rear-side drive or engine compartment of the vehicle ( FIG. 3).

In addition, two batteries B, a fuel tank T and a drive device (not shown here) for the switch housed in the air shaft 895 , which can be actuated via the two thermostats H _St and H _{Dr, are also} accommodated in the storage space.

Fig. 3 shows in a longitudinal section of the vehicle from the Beifah rerseite from the thermostatically controlled bypass valve 905 w from branched supply line 1 to the latent heat accumulator L, via which the cooling water by means of the pump P when preheating the motor M through the latent heat accumulator and via one from the accumulator branched supply line 4 and a supply line 5 is pumped through the radiator R _H ( Fig. 2).

After starting the engine M, the cooling water is at a temperature that is slightly higher than the starting temperature intended for starting the engine, by means of the engine's own pump to a large extent via the bypass line 2 branched off from the bypass valve 905 w and via a check valve , and pumped through the supply line 5 through the radiator and to a small extent via the branch line branched from the bypass line 2 drosselba re connecting line 3 , and pumped through the branch line branched off from the bypass valve 1 through the heat accumulator, from which the smaller part of the cooling water then About the line 4 and the supply line 5 is also pumped through the radiator or fed back into the cooling water circuit.

Fig. 4 shows a bypass valve 905 w according to DE 195 43 348 A1, but without any additional electromagnetic control, so that the lower flange 912 of the Ventilge housing shown in DE 195 43 348 A1 is replaced by a simple flange 912 w, the connection of which for the bypass line 2 to the radiator R _H is attached centrally to the flange.

The valve body housed in the valve housing is here at a cooling water temperature that is slightly higher than the intended starting temperature for starting the engine, pushed into its upper end position so that the cooling water flowing in on the lower outside of the valve flows via the bypass line 2 .

So that the valve body of the thermostatically controlled bypass valve 905 i with additional electromagnetic control according to DE 195 43 348 A1 more easily detaches from its upper end position when the cooling water temperature drops slightly below the operating temperature, one or two small axially directed bores 905 are in this valve i attached to the outer edge of the lower flange 915 by the valve body, so that a pressure equalization between the lower and upper part of the cooling water is formed. In a bypass valve 905 w shown here, no hole has to be provided on the lower flange 915 of the valve body, since a connection between the bypass line 2 and the supply line 1 to the latent heat accumulator is forced through the throttling connecting line 3 when the valve body is pushed into its upper end position, so that the amount of cooling water passed through the latent heat accumulator while the engine is running is determined only by the thermostatically controlled throttle valve installed in the throttling connecting line.

Claims (4)

1. A method for preheating an internal combustion engine, with a cooling water circuit, in which a latent heat accumulator (L), a controllable circulation pump (P) and an engine-specific cooling water pump (P _M ) are arranged, with a bypass valve controlled as a function of the cooling water temperature ( 905 w ), which passes the cooling water at low cooling water temperature over the latent heat storage and at high cooling water temperature past the latent heat storage, whereby before starting the internal combustion engine the circulation pump is switched on and the internal combustion engine is preheated using the heat in the latent heat storage, characterized in that parallel to the bypass valve ( 905 w) a with a changeable throttle resistance connecting line ( 3 ) is arranged, which allows a throttled flow of cooling water through the latent heat accumulator (L) through at elevated cooling water temperature or closed bypass valve, so d Then ate the remaining or larger part of the cooling water quantity determined by the respective throttling via a bypass line branched off from the bypass valve and past the latent heat accumulator ( 2 ) and via a check valve together with the cooling water quantity flowing through the latent heat accumulator and fed back into the cooling water circuit. 2. The method according to claim 1, characterized in that for preheating the internal combustion engine via the controllable circulation pump (P) the ignition key of the ignition lock (I) in a first position ( 2 ) and for starting the internal combustion engine ne the ignition key in a second position ( 1 ) is brought, the time for starting when a certain engine temperature is reached is indicated by a thermal switch (T ₁ ) by lighting up a signal lamp (S). 3. The method according to claim 1, characterized in that in the parallel to the bypass valve ( 905 w) arranged Ver connection line ( 3 ) a thermostatically controlled throttle valve is installed, which reduces its passage cross section with increasing engine temperature from a certain maximum to a certain minimum cross section . 4. The method according to claim 1, characterized in that the parallel to the bypass valve ( 905 w) arranged connec tion line ( 3 ) engine compartment is housed.