DE4214850A1 - Heating IC engine using heat carrier circulation system conducted across heater - involves conducting heat carrier with priority across engine cylinder head with part of circulated heat carrier controlled so that it is also led through engine cylinder block. - Google Patents

Abstract

The temp. of the cylinder block (1a) is followed up by maintaining a certain temp. difference (DELTA T) to the temp. of the cylinder head (1b). A heat supply system (11) is provided driven by outside energy, esp. designed similar to a constant flow heater, which can be connected to a stationary electric current network. The heat circulation system (3), with the IC engine not yet operationally heated up, takes up heat from the heater (8) and gives priority to flow through the cylinder head (1b). The circulation entering directly in the cylinder head, essentially only acts on the engine inlet ducts (20,21) and their surroundings running in the cylinder head. ADVANTAGES - Improves starting of engine and optimises exhaust gas emissions. Improves fuel consumption.

Description

The invention relates to a method for heating a Internal combustion engine with a heater leading heat transfer circuit, which is primarily via the Internal combustion engine cylinder head is directed. Further The invention relates to an internal combustion engine with a Heat transfer circuit, which is not yet warmer Internal combustion engine heat up in a heating device takes and primarily the engine cylinder head flows through.

The relevant prior art is DE-OS 29 16 216. Accordingly, it is known to have an internal combustion engine in front of it Preheat start or quicker after start bring the operating temperature by the otherwise heat transfer medium for cooling the internal combustion engine circuit by means of a heat storage in particular trained heater is heated. Prefers initially only the internal combustion engine cylinder head warmed, as this causes the firing engine improved and after the start also the warm-up behavior, for example with regard to the expected exhaust emissions can be optimized.

Further potential for improvement in such a It is the task of demonstrating internal combustion engine heating of the present invention.

With regard to the method of heating is as a solution this task provided that part of the circulated Heat transfer medium controlled in this way also by the burner engine cylinder block is directed that the tem temperature of the cylinder block while maintaining a ge know the temperature difference of that of the cylinder head is tracked.

With regard to the internal combustion engine as such gene the task is solved in that the directly in the heat transfer circuit entering the cylinder head in the we only the burning in the cylinder head engine inlet ducts or their walls or vice versa exercise.

Advantageous further developments of the invention are Content of the subclaims.

Although it is desirable, preference is given to the Brenn engine cylinder head and especially the one preheat or accelerate to warm up Optimal mixture preparation as short as possible in the channels and combustion in the combustion chambers of the Achieve internal combustion engine, so should still use increasing heating of the cylinder head also the Zylin The block can be heated to reduce the friction loss Operation of the internal combustion engine also as early as possible to reduce early. In order to be the much more effective to give preference to cylinder head heating according to the cylinder block heating Cylinder head heating practically tracked. This can happen with for example, through an appropriately controlled division of the heat transfer flow take place on the head and block. Then the cylinder head receives a greater proportion of the heat  carrier than the cylinder block and is therefore also warmed more intensely. In particular, however, if initially only the cylinder head is flowed through with Er range of a certain temperature difference between Head and block the heat transfer circuit for a certain Time can also be guided through the block. After a ver however, the temperature difference will decrease Heat transfer circuit again bypassing the cylinder blocks essentially only over the cylinder head tet. As soon as the temperature difference between the Cylinder head and the cylinder block due to the heating tion of the cylinder head has reached a certain height, In addition to the cylinder head, the Zy linderblock heated until this temperature difference between cylinder head and cylinder block is reduced. On then the engine-Zy lind head warmed alone. After a new appearance a certain temperature difference between these two Components can again the cylinder block he be warmed and then again the cylinder head al rope; However, the internal combustion engine should machines have reached their operating temperature of course, the preheating or heating process has been completed det. Switching the warming or preheating performing heat transfer circuit can by means suitable valves either time-controlled or tem temperature controlled. In the former case, you can the appropriate periods of time after which the certain tempe difference in temperature is reached or reduced again, can be determined by series of tests in the second Suitably placed temperature sensors on the cylinder can be used the block and attached to the cylinder head or in pass in the heat transfer circuit with which then current temperature values measured as well as current tempera door differences can be determined.  

As already explained, by means of the Brenn Motor-independent heating device in particular the engine cylinder head preheated or in heated intensively, as this improves the warm-up hold and the resulting reduced exhaust emissions can be achieved with reduced fuel consumption can. Especially with mixture-compressing internal combustion it is particularly advantageous for machines, primarily the ver in the cylinder head of the internal combustion engine to heat up the current inlet ducts, because in this one let channels form the mixture, or because it is too ver prevent liquid fuel from sticking to the walls the inlet channels settles. Acted on according to the invention thus the heat transfer medium entering the cylinder head cycle essentially only the environment of the one let channels, especially where one of a focal sprayed fuel jet on meets. These channel areas should therefore be a "hot spot" represent. For this, the heat transfer medium will correspond accordingly in the cylinder head. In particular, it flows Heat transfer medium on the intake port side into the cylinder head and leaves this also on the inlet channel side, without the other long side of a row cylin, for example to flow through the head, on which then the off let channels can be provided. It goes without saying this dead water area at the outlet channels heat long term, the concentrated heat supply through the heated heat transfer medium in the heater however, desirably follows only intake port egg tig. This measure can be increased by the fact that with a multi-cylinder internal combustion engine per cylinder a separate entry or exit, d. H. general About occurs for the heat transfer circuit, is provided.

Is it the heater for the Wärmeträ circulation around a heat accumulator, this heat  storage is usually caused by the waste heat from operation loaded warm internal combustion engine. However, it can be about additional loading of the heat accumulator another external energy source may be provided. For example, electrical energy from a Electricity network are withdrawn, for example the heating medium circuit or the heat via heating rods memory is heated directly. To go beyond Turning off the engine the engine rest to be able to use heat when the heat storage is through did not fully load the previous operation is a device for conveying the heat carrier in / through the heat accumulator after being switched off the internal combustion engine can be provided. In the simplest Fall is an additional pump for the already existing Heat transfer medium that is required to keep the burning Preheat the engine, even after stopping the burner engine operated for a certain period of time taken.

This, as well as other advantages of the invention also preferred from the following description management examples can be seen, some of which are only in Principle sketches are shown.

In Fig. 1, a heat transfer circuit of an internal combustion engine that enables an internal combustion engine heating light is shown in principle.

The designated with the reference number 1 internal combustion engine consists of a cylinder block 1 a, and a cylinder head 1 b. A coolant pump 2 driven by the internal combustion engine 1 is provided , with which a coolant can be circulated in a heat transfer circuit 3 represented by lines, as is known. The known elements of this heat transfer circuit 3 are a thermostatic valve 4 , a cooler 5 , and two heating heat exchangers 6 a, 6 b, with upstream heating valves 7 a, 7 b.

In addition to these usual elements, the heat transfer circuit shown in FIG. 1 contains a heating device 8 in the form of a latent heat accumulator, an additional circulation pump 9 that can be driven independently of the internal combustion engine, and several individual line branches that release or shut off control valves 10 a to 10 e. The re control valve 10 a is located downstream of the circulating pump 9 and upstream of the heating device 8 . Downstream of the re gel valve 10 b is provided with external energy, ie in particular special electrically operable heat supply device 11 to the circulating in the heat transfer circuit Wärmeträgermit tel. The control valve 10 c is located in a line branch which conveys heat transfer medium directly into the cylinder head 1 b of the internal combustion engine 1 , while the control valve 10 d is arranged in a line branch through which the heat transfer medium can get into the cylinder block 1 a. The path of the heat transfer medium from the cylinder block 1 a to the cylinder head 1 b is not shown, since this is also customary here, as is the case with internal combustion engines. Furthermore, a control valve 10 e is provided in the usual heating return.

As already mentioned, the heat transfer circuit is switched as usual when the internal combustion engine 1 is warm. This means that, depending on the temperature of the heat transfer medium by appropriate position of Ther mostatventiles 4, the heat transfer medium via the Kühlmit telpump 2 either in the short circuit in Chen essentially only via the cylinder block 1 a and the cylinder head 1 b, or - if one Cooling of the heat transfer medium is required - is additionally circulated via the cooler 5 .

In addition, if the waste heat of the internal combustion engine 1 is used for example for heating a vehicle driven by the internal combustion engine, the heating heat exchangers 6 a, 6 b are also flowed through. For this purpose, the heating valves 7 a, 7 b ge opens, the control valve 10 e is also open, so that the discharged from the cylinder head 1 b and the heat exchanger 6 a, 6 b flowing through heat transfer medium upstream of the coolant pump 2 again in the actual Internal combustion engine heat transfer circuit can be recycled. In this stationary operating state when the internal combustion engine is warm, at least the control valves 10 b, 10 c, 10 d are then closed.

If there is enough waste heat from the internal combustion engine 1 , this waste heat can be stored in the latent heat storage / heating device 8 . In this case, the control valve 10 a is opened so that the heat carrier flows through the latent heat accumulator and can give off excess thermal energy. The return of this heat transfer medium also takes place via the control valve 10 e and the heating return already described.

The stored in this heat storage or in this Heizeinrich device 8 thermal energy should be used to who to preheat the internal combustion engine 1 before a start or to heat it faster immediately after a start. In the latter case in particular, the strategy for internal combustion engine heating explained in more detail is particularly advantageous. Starting from the start of the internal combustion engine, when the coolant pump 2 has stopped - a clutch can be provided for this purpose - the additional circulation pump 9 is started up and the control valves 10 a, 10 c are opened. The control valves 10 b, 10 e remain closed with this internal combustion engine heating. If necessary, the heat exchangers 6 a, 6 b can be flowed through, so that the heating valves 7 a, 7 b can be opened.

First, the control valve 10 d is closed. When the circulation pump 9 is in operation, the heat transfer medium is now passed through the heat accumulator, heats up in it and from there passes directly into the cylinder head 1 b of the internal combustion engine 1 . Here, the heat transfer medium releases the previously absorbed heat to the cylinder head and then leaves it to be sucked in again by the circulation pump 9 . In this way, as desired, the cylinder head 1 b is heated, noteworthy heating of the cylinder block 1 a does not take place.

After a certain period of time, a certain difference between the temperature of the cylinder head 1 b and the temperature of the cylinder block 1 a is reached. This temperature difference can be determined, for example, by means of a suitably attached temperature sensor 12 a, 12 b. As explained in the introduction to the description, the cylinder block 1 a should now also be heated. Thus, the heat transfer circuit is also guided through the cylinder block 1 a for a certain time, for which purpose the control valve 10 c is closed and the control valve 10 d is opened. After a reduction in the temperature difference between the cylinder head 1 b and the cylinder block 1 a, the heat transfer circuit, on the other hand, is bypassed the cylinder block 1 a essentially only via the cylinder head 1 b passed. This means that always closed when not operated circulation pump 9 and open control valve 10 a now the control valve 10 d again and the control valve 10 c is opened again.

The temperature curves for the heat accumulator and the components to be heated in the internal combustion engine 1 to be heated with this heating strategy are shown in the temperature-time diagram according to FIG. 2. The temperatures in the heat accumulator (curve 8 '), in the cylinder block (curve 1 a') and in the cylinder head (curve 1 b ') are shown above the horizontal time axis.

At time t ₀ , the process begins with the commissioning of the circulation pump 9 with the control valve 10 d closed and the control valve 10 c open. As can be seen, only the cylinder head 1 b heats up. At the time t ₁ , such a high temperature difference between the cylinder head and the cylinder block is reached that now the cylinder block 1 a is heated. As described above, the control valve 10 d is opened and the control valve 10 c is closed. At time t ₂ , this temperature difference is reduced to such an extent that now only cylinder head 1 b of internal combustion engine 1 is heated again until time t ₃ . In the period from t ₃ to t _4, however, the heat transfer medium is initially introduced into the cylinder block 1 a again. At t ₄ , the temperature difference between the cylinder head and cylinder block Zy is reduced again so far that only the cylinder head 1 b is heated in the following. Finally, the regular coolant pump 2 is put into operation at time t ₅ . At the same time, the circulation pump 9 can be switched off. Also, the re regulating valves 10 c, 10 d are now closed.

During this entire heating process in the period from t ₀ to t ₅ , the temperature in the heat accumulator / heating device 8 naturally decreases continuously, as the curve profile 8 'shows. The advantages of this heating strategy are that when starting the regular coolant pump 2 no thermal shock load can occur, since the temperature level of the crankcase is already essentially matched to that of the cylinder head. Furthermore, the overall engine characteristics are not adversely affected by the tracked heating of the crankcase, since any electronic engine control that may be present does not receive divergent information about different temperature conditions in the cylinder head or in the crankcase.

Of course, this process can also be carried out in a similar manner if the start of the internal combustion engine does not take place until time t ₅ and the heating process described is carried out as a preheating process, for example controlled by a timer or also started by manual switching on. Finally, at time t ₆ , the entire internal combustion engine 1 has reached its statio nary operating temperature and cooling of the internal combustion engine by the heat transfer medium is required, the heat accumulator / heating device 8 can be reloaded, like the curve profile 8 'beyond time t ₆ shows. The circuit for the heat transfer circuit 3 required for this was already described above.

Fig. 1 shows another possible detail of a heat transfer circuit according to the invention of an internal combustion engine. In a line branch running parallel to the heat storage / heating device 8 , a heat supply device 11 that can be operated with external energy is arranged. In particular, this heat supply device 11 can be configured similarly to a water heater and can be connected to a stationary electrical power network. In the associated line branch, which branches off downstream of the heat accumulator / heating device 8 and opens upstream of the circulation pump 9 , the control valve denoted by reference number 10 b is arranged. Thus, if the control valves 10 a, 10 b are open, the control valves 10 c, 10 d, 10 e and the heating valves 7 a, 7 b are closed and the circulation pump 9 is simultaneously operated - for example also via the stationary electrical power supply - then the Heat storage 8 can be loaded via this external heat supply device 11 . This operation is useful, for example, when the internal combustion engine has not reached its steady operating temperature during its last startup, for example because of short-range operation, so that loading of the heat accumulator 8 by the waste heat of the internal combustion engine could not take place.

In Figs. 3, 4, an advantageous internal combustion engine for preheating or heating by means of a heating device permitting heat transfer medium circuit is is set. Fig. 3 shows a section through a row cylinder head 1 b of a multi-cylinder internal combustion engine parallel to the sealing plane between the Zylin derkopf 1 b and the cylinder block 1 a of an internal combustion engine 1 , while Fig. 4 shows the cross section AA of Fig. 3 by the Cylinder head 1 b shows. Only the elements that are essential for the essence of the invention are described in more detail, but are not explained.

Shown is a cylinder head of a six-cylinder internal combustion engine with two inlet channels 20 , 21 per cylinder. The injection jet of an injection valve 22 to guide the fuel also opens into these inlet channels 20 , 21 for combustion air. After combustion has taken place in the combustion chamber 31 , the exhaust gas is discharged from two cylinder ducts 23 , 24 per cylinder from the cylinder head 1 b.

It is desirable to have increased component temperatures in the area of the inlet channels 20 , 21 as shortly as possible after a cold start of the internal combustion engine in order to improve the mixing of the combustion air with the fuel in the inlet channels 20 , 21 , ie to minimize the wall deposits of fuel. Therefore, the internal combustion engine cylinder head 1 b is preheated, particularly in the area of the inlet ducts 20 , 21, by means of a heating device 8 (heat accumulator) or is heated up more intensively. The heating device 8 through-flowing and promoted by the circulating pump 9 heat transfer circuit 3 is thus performed within the cylinder head 1 essentially in a longitudinal channel 25 which is rich in the inlet channels 20 , 21 Be. For this purpose, the heat transfer circuit 3 can be supplied via an end-side inlet bore 26 and discharged via an outlet opening 27 arranged on the opposite end side.

However, it is also possible for each cylinder to have its own transition 28 for the heat transfer circuit 3 , as is shown schematically in FIG. 3 and explicitly in FIG. 4. Accordingly, starting from a manifold 29 for each cylinder, a water nozzle 30 in the cooling water chamber of the cylinder head 1 b near the A lasskanäle 20 , 21st The heat transfer medium is removed again via the outlet opening 27 . However, this representation only shows a basic arrangement. In addition, a variety of modifications are possible, which fall under the content of the claims.

Claims (8)

1. A method for heating an internal combustion engine ( 1 ) with a via a heating device ( 8 ) leading heat transfer circuit ( 3 ), which is passed primarily through the internal combustion engine cylinder head ( 1 b), characterized in that part of the circulated heat transfer medium is also controlled in this way passed through the engine cylinder block ( 1 a) that the temperature of the cylinder block ( 1 a) while maintaining a certain temperature difference (ΔT) that of the cylinder head ( 1 b) is tracked. 2. The method according to claim 1, wherein the heat transfer circuit ( 3 ) is initially passed bypassing the internal combustion engine cylinder block ( 1 a) essentially only via the internal combustion engine cylinder head ( 1 b), characterized in that upon reaching a knowledge of ge Temperature difference between the cylinder head ( 1 b ') and the cylinder block ( 1 a') the heat transfer circuit run ( 3 ) for a certain time also through the cylinder block ( 1 a), and that after a reduction in the temperature difference of the heat transfer circuit ( 3 ) again bypassing the cylinder block Zy ( 1 a) is passed essentially only over the cylinder head ( 1 b). 3. The method according to claim 1 or 2, characterized in that the temperature difference between the cylinder head ( 1 b ') and cylinder block ( 1 a') is determined by measurement. 4. Internal combustion engine with a heat transfer circuit ( 3 ), which takes up heat when the internal combustion engine is not yet operational ( 1 ) in a heating device ( 8 ) and primarily flows through the internal combustion engine cylinder head ( 1 b), characterized in that the directly into the Cylin derkopf ( 1 b) entering heat transfer circuit ( 3 ) essentially only in the cylinder head ( 1 b) run the internal combustion engine inlet ducts ( 20 , 21 ) and their environment. 5. Internal combustion engine according to claim 4, characterized in that the heat transfer medium flows at high speed outside the Wandbe rich of the inlet channels ( 20 , 21 ), which is wetted on the inside with fuel. 6. Multi-cylinder internal combustion engine with in-line cylinders according to claim 4 or 5, characterized in that each cylinder has its own transition ( 28 ) for the heat transfer circuit ( 3 ) is seen before. 7. Internal combustion engine according to one of claims 4 to 6, wherein the heating device ( 8 ) is designed as a heat accumulator, in particular as a latent heat accumulator, characterized by a device for conveying the heat transfer medium in / through the heat accumulator after switching off the internal combustion engine. 8. Internal combustion engine according to one of claims 4 to 7, wherein the heating device ( 8 ) is designed as a heat accumulator, in particular as a latent heat accumulator, characterized by an externally operable heat supply device ( 11 ) for the heat accumulator.