JPH04124451A - Internal combustion engine and driving method thereof - Google Patents

Abstract

PURPOSE:To reduce the emission of exhaust gas, prevent the wasteful consumption of fuel and perform efficient ignition at the time of cold start by setting the atmospheric condition of combustion air on the basis of the optimum combustion air temperature change corresponding to the driven condition of an internal combustion engine, before the intake of the combustion air into a combustion chamber. CONSTITUTION:Exhaust gas from an exhaust manifold 24 is supplied to a heat accumulating device 22 and released around downstream of the heat accumulating device 22 after passing an exhaust gas device. Combustion air passes an air filter 12 and then an air lead-in duct 14, and is fed into the combustion chamber of an engine 10 from an intake manifold 16. When a three-way valve 18 is switched by the detection signal of a temperature measuring device 47, the combustion air passes a branch duct 20, and is heated by the heat accumulating device 22 and then fed into the combustion chamber of the engine 10 from the intake manifold 16. The atmospheric condition of combustion air is thus set on the basis of the optimum temperature change corresponding to the driven condition of the engine 10. The emission of exhaust gas is thereby reduced, the wasteful consumption of fuel is prevented, and efficient ignition is performed at the time of cold start.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method of driving an internal combustion engine and an internal combustion engine, and more particularly to a method of driving an internal combustion engine of an automobile and the internal combustion engine.

(Prior Art) Automobiles are required to run under various operating conditions.
The internal combustion engine must be able to operate under wide atmospheric conditions. On the one hand, these internal combustion engines must be able to start at low ambient temperatures, and on the other hand, they must be driven at high speeds and provide considerable power, for example when driving on highways. Typically, for more than 90% of its operating life, an automobile's internal combustion engine is operated at low rotational speeds and low loads.

In this case it is appropriate to highlight three critical driving conditions:
These operating conditions are cold starting, low part load and full load operation. These three drive modes have very different conditions with respect to the combustion gas temperature just before and during the expansion stroke, and therefore have different fuel consumption and exhaust gas emissions for each.

In the case of diesel engines, the noise varies greatly depending on the driving conditions.

The temperature changes with time and position within the engine of the combustion air and the combustion mixture of the combustion gases within the combustion chamber are highly dependent on the instantaneous operating temperature of the engine at a given stage shortly before and during the expansion stroke. Ru. In particular, it depends greatly on the temperature of the walls of the combustion space, the temperature increase of the combustion air due to compression within the engine, and also the temperature of the air when it enters the combustion chamber and the respective masses of the combustion air and fuel. Depends on it. The engine operating temperature is highly dependent on the instantaneous load conditions, the rotational speed, and the conditions of the immediately preceding operating phase, for example whether the temperature atmosphere is a rising or falling temperature atmosphere.

The temperature rise of combustion air due to engine compression depends primarily on the compression ratio determined by the engine design, but also on the engine operating temperature. If the operating temperature of the engine is high,
The temperature increase caused by compression within the engine is also higher. The reason for this is that less heat is released from the combustion air and the compression pressure and therefore the energy supply from start-up is kept high due to the inertia of the engine to the combustion air. If the operating temperature of the engine is low, such as during a cold start, the temperature rise due to compression will also be low. The two important components that influence the height of the compression temperature therefore increase in relation to each other.

The change in combustion air temperature just before and during the expansion stroke is an important consideration that affects the quality of combustion within the engine. These determine the fuel consumption, the extent of harmful exhaust gas emissions and, in the case of diesel engines, the noise output. Additionally, pressure height and variation during the expansion stroke also plays another role. Changes in temperature and pressure are, within limits, interchangeable; in other words, a drop in pressure results in a drop in temperature, and vice versa.

(Problem to be Solved by the Invention) As mentioned above, the compression ratio setting conditions determined at all operating stages of the engine are made in a compromise manner, so the optimum combustion gas temperature is actually not ideal at any operating stage. It is never held in value. The reason for this is that the temperature rise in the combustion air due to engine compression during cold starts, for example, is very low and therefore the combustion air temperature is well below the optimum value, whereas at full load, the temperature rise in the combustion air due to engine compression is very low. The temperature increase is very high and for this reason the combustion air temperature is much higher than optimum. Even under low part-load conditions, which have a significant effect if sustained, the optimum combustion air temperature is barely maintained.

It is therefore an object of the invention to control the combustion air temperature immediately before and during the expansion stroke in a timely manner depending on the respective operating conditions.

(Means for Solving the Problems) In order to achieve the above object, the present invention as a basic method provides a method for driving an internal combustion engine in which the compression ratio can be set to the lowest value suitable for the preparatory operating conditions of the engine. Before the combustion air is sent into the combustion chamber of the internal combustion engine, the atmospheric conditions of the combustion air are set based on an optimum combustion air temperature change corresponding to the driving conditions of the internal combustion engine. There is.

(Function) In the present invention, the atmospheric conditions of the combustion air include, for example, its temperature and flow rate, and before the combustion air is sent into the combustion chamber of the internal combustion engine, the optimum temperature change corresponding to the driving conditions of the internal combustion engine is determined. Based on this, at least one of the temperature and flow rate of the combustion air is controlled.

Such control reduces exhaust gas emissions, prevents wasted fuel consumption, and provides efficient ignition during cold starts.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

1 to 8 are explanatory diagrams showing the configuration of an internal combustion engine used in the first to eighth embodiments of the present invention, respectively.

In all the drawings, 10 is an engine, a refrigerant circuit 15 through which a cooling medium flows is attached to the engine 10, a radiator circuit 17 is connected to one end of this refrigerant circuit 15, and a cooling device 11 is connected to this radiator circuit 17. is provided. Further, a heating circuit 28 is provided at the other end of the refrigerant circuit 15.
is connected to the heating circuit 28, and the heating device 13 is provided in the heating circuit 28. The radiator circuit 17 and the heating circuit 28 are integrated at a connection point 19 and return to the engine 10 through an opening 42 via a return duct 21.

The cooling device 11 includes an engine thermostat 25, a radiator 27 having a radiator fan 29, and a correction tank 37. This type of cooling device is of a well known type and will not be described in detail. The heating device 13 also includes a vehicle heating device 26, a heating blower 39, and a control valve 41.

Combustion air is supplied to the engine 10 through an air filter 12 , and the combustion air is sent from the filter 12 to an air introduction duct 14 connected to an intake manifold 16 of the engine 10 . This intake manifold 16 is preferably designed to have a low heat capacity and is therefore made of a material with a relatively low heat capacity. Additionally, the intake manifold 16 is provided with thermal insulation. According to a preferred design, this may be, for example, in the form of a ceramic-coated double-walled metal seed structure, and if necessary made into a vacuum structure.

In FIG. 1, a three-way valve 18 is located downstream from the filter 12 in the air inlet duct 14 and connects the air inlet duct 14 to the intake manifold 16 by means of the three-way valve 18. Furthermore, a branch duct 20 is provided, which opens into the three-way valve 18 and which branches off from the air introduction duct 14 downstream from the air filter 12 and in which a heat storage device 22 is installed. It is arranged. The heat storage device 22 has a double duct structure,
One duct is a branch duct 20 through which combustion air flows, and the other duct is supplied with heated exhaust gas for heating a heat storage device 22 . The exhaust gas is supplied to the heat storage device 22 via an exhaust manifold 24, which is open to the environment downstream of the heat storage device 22 via the exhaust gas system.

FIG. 2 shows a device with a heat storage device that is not a double duct arrangement. The hot cooling medium is sent out from the outlet 30 of the engine 10 and enters the heating circuit 28 , first passing through the water-air heat exchanger 31 and then being sent to the vehicle heating device 26 . The cooling medium is then pumped into the heat storage device 22 via the pump 32 . The heating circuit 13 connected to the heat storage device 22 has a branch point 34 connected to a bypass 36, which bypasses the engine 10, rejoins the heating circuit 28 upstream from the heat exchanger 31, and has a non-return check. A valve 38 is provided.

There is a shutoff valve 40 in the heating circuit 828 downstream of the branch point 34 to prevent the flow of cooling medium back into the engine 10 at the opening 42 and to allow the cooling medium to flow through the bypass 36. can.

The intake manifold 16 is connected to an air introduction duct 14 , which is provided with a three-way valve 44 adjacent to the air filter 12 , from which a branch duct 20 is arranged via a heat exchanger 31 at point 46 The air inlet manifold duct 14 is reconnected with the air inlet manifold duct 14.

By the way, when the engine 10 is started from a cold state, the shutoff valve 40 is closed and the pump 32 supplies the cooling medium in the shortened circuit from the heat storage device 22 to the vehicle heating device 26 through the bypass 36 and the heat exchanger 31. . From here, the cooling medium is again conveyed by the pump 32 via the heat storage device 22 in order to supply further heat to the heat exchanger 31 and to the vehicle heating device 26 .

As soon as the engine 10 reaches a sufficient operating temperature, the isolation valve 40
is opened and the pump 32 then pumps the coolant through the engine 10 due to the resistance of the check valve 30 and the coolant flows from the engine 10 through the heat exchanger 31 and the vehicle heating device 26 and back to the heat storage device 22. , the heat exchanger 31 is thus filled with hot cooling medium.

When starting from a cold state, the three-way valve 44 is set so that combustion air flows from the branch duct 20 through the heat exchanger 31 and high-temperature combustion air is supplied to the engine 10. If the combustion air does not require heating, the three-way valve 44 is reset and the combustion air is routed through the filter 12 to the air inlet duct 14.
The air is supplied directly to the intake manifold 16 through the air.

The apparatus according to the embodiment shown in FIG. 3 is the same as the apparatus according to the embodiment shown in FIG. 2 except that the branch duct 20 is not provided. Instead of selective switching of the device, the cooling medium coming from the engine 10 can be passed through the bypass 35 to bypass the heat exchanger 31, or alternatively the cooling medium can be transferred to the heat exchanger 31 after the choke 33 in the bypass 35 is closed. This is done by flowing water through the water.

In the embodiment shown in FIG. 4, the heat storage device 22 is equipped with a single duct system, and heating of the heat storage device 22 by engine exhaust gas or heating of the combustion air flowing through the device is selected. In this device, a three-way valve 44 is provided adjacent to the air filter 12, via which the air introduction duct 14 is connected to the intake manifold 16. The branch duct 20a is arranged to connect the three-way valve 44 and the three-way valve 48, and the three-way valve 48 connects the duct 5 to another three-way valve 52.
Combined via 0.

For this reason, the duct 50 is arranged via the heat storage device 22. A branch duct 20b is arranged adjacent to the three-way valve 52, which opens into the air inlet duct 14 at a point 42. Additionally, three-way valve 52 is coupled via duct 54 to three-way valve 56, which in turn is coupled to exhaust manifold 24. Two three-way valves48.
56 are coupled together by a duct 58 that bypasses the heat storage device 22, and the duct 58 is coupled to an exhaust device 60.

When starting from a cold state or when it is necessary to heat the combustion air, the three-way valve 44, 48, 52, 56 allows the combustion air flowing in from the air filter 12 to pass through the branch duct 20b and the duct 50. The air flows into the heat storage device 22 and flows from the heat storage device 22 through the branch duct 20b to the air introduction duct 14.
is set to flow. On the other hand, engine exhaust gas flows from the exhaust manifold 24 to a duct 58 through a three-way valve 56.
It flows into the exhaust device 60. If heating of the combustion air is not required, the three-way valve 44, 48, 52° 56 is switched and the combustion air entering via the filter 12 is routed to the air inlet duct 14.
It is set so that it flows straight through. At the same time, the exhaust gas passes through the three-way valve 56 to the duct 54, passes through the three-way valve 52 to the duct 50, is used to heat the heat storage device 22, and then flows through the three-way valve 48 from within the duct 58 into the exhaust system 60. It will be done.

The apparatus of the embodiment shown in FIG. 5 is of a type in which the heat storage device 22 is heated by engine exhaust gas, and the heat storage device 22 has one duct device, and in this case, the heat storage device 22 is heated by the exhaust gas. This is done indirectly using an air circuit that picks up heat from the air. In the device of FIG. 5, the air introduction duct 14
is connected from the air filter 12 to the intake manifold 16 on the engine 10, and a branch duct 20 is coupled downstream of the air filter 12, which branch duct 20 is coupled to an exhaust gas-air heat exchanger 64, and further a heat storage device. 22 and a three-way valve 18, it is connected to the air introduction duct 14.

The exhaust manifold 24 is arranged via an exhaust gas-air heat exchanger 64. The return duct 66 is the branch duct 20
, and selectively branches between the heat storage device 22 and the three-way valve 18 .

This return duct 66 is connected via a blower 68 to a three-way valve 62 located downstream of the heat exchanger 64 .

During a cold start or when it is necessary to preheat the combustion air for some other reason, the combustion air drawn through the filter 12 is routed through the duct 20 to the exhaust gas-air heat exchanger 6.
4. The three-way valve 18 is set so that the air flows into the heat storage device 22 and then through the three-way valve 18 from the air introduction duct 14, through the intake manifold 16, and into the engine 10.

As soon as the preheating of the combustion air is carried out, the three-way valve 18
Combustion air is passed through the air filter 12 through the air introduction duct 14
The air is set to flow to the intake manifold 16 through the air. On the other hand, the three-way valve 62 includes a closed air circuit arranged via an exhaust gas-air heat exchanger 64, a heat storage device 22, and a blower 6.
8 are reset so that they are connected to each other. The blower 68 enters operation with this setting and maintains the air circuit via the return duct 66, the exhaust gas-air heat exchanger 64, the heat storage device 22,
The air circulating in this circuit and heated in the exhaust gas-air heat exchanger 64 heats the heat storage device 22 .

FIG. 6 shows a further embodiment of the arrangement of the device, in which the heat storage device 22 can be heated indirectly by a cooling medium on the one hand and by exhaust gas on the other hand. Although the apparatus according to FIG. 6 is generally similar to the apparatus of FIG.
An exhaust gas water heat exchanger 70 is provided which is placed in the heating diagram i28 in a branch duct leading to the air heat exchanger. A cooling medium flows through this heat exchanger 70 at all times. The exhaust gas duct 72 extending from the exhaust manifold 24 is
It is arranged via an exhaust gas-water heat exchanger 70, and is further provided with a bypass 74 for this exhaust gas-water heat exchanger 70. This bypass 74 is provided with a shutoff valve 76 .

Unless the cooling medium reaches the required operating temperature, the isolation valve 7
6 allows the hot exhaust gas to flow through the exhaust gas-to-water heat exchanger 70, whereby the exhaust gas releases heat to the cooling medium.

When additional heating of the combustion air by the exhaust gases is no longer required, the isolation valve 76 opens and the exhaust gases can bypass the heat exchanger 70.

The device of the embodiment shown in FIG. 7 differs from the device shown in FIG. It branches at a point 82 and is connected to the inlet side of a replenisher 84 . From the outlet or pressure side of the replenisher 84, the branch duct 80 returns to the branch duct 20 via an adjustable choke 86, a three-way valve 90,88.

A three-way valve 9 disposed between the choke 86 and the three-way valve 88
A duct 92 is arranged from 0, which bypasses the heat storage device 22 and opens into the air inlet duct 14 immediately downstream of the three-way valve 18.

The arrangement of FIG. 7 can direct combustion air from the air filter 12 into the intake manifold 16 or can reconfigure the three-way valve 18 and then flow the combustion air through the branch duct 20. In this case, the combustion air is directly supplied via the heat storage device 22 by setting the three-way valve 88.
Or it flows through the replenisher 84.

After leaving the replenisher 84, the temperature of the combustion air is at the choke 8.
You can add and increase it by setting 6.

If further heating is required, the three-way valve 90
The combustion air coming through 4 is arranged to flow through the heat storage device 22 . In other cases, the combustion air can be passed straight through the duct 92 to the air introduction duct and the heat storage device 22 is bypassed.

Similarly, combustion air from the replenisher 84 may be selectively passed through a heat exchanger supplied with heat emitted from the engine 10 to further heat the combustion air.

The apparatus of the embodiment shown in FIG. Either the combustion air can be passed directly through the heat exchanger 31 or directly into the air inlet duct 14 (as in the device in FIG.
6 is sent to the entrance side. This replenisher 96 is provided with a check valve 98 . Similarly, a check valve 100 is provided on the pressure side of the piston replenisher 96. The pressure side of the piston replenisher 96 is connected to the air inlet duct between the three-way valves 44.94, and the combustion air coming from the replenisher 96 optionally flows through the heat exchanger 31 or bypasses it.

The piston type replenisher 96 is driven by a belt 102 from the engine crankshaft.
The piston 104 of the engine 10 moves in synchronization with the piston of the engine 10. Piston 1 of replenisher 96 for piston of engine 10
The phase relationship of 04 is varied by a conventional setting device 10B, which can vary the ratio of the running lengths of the driving and driven sides of the belt. A change in the phase relationship between the filler 96 and the engine 10 causes a change in the phase relationship between the opening of the engine cylinder to be filled and the pump stroke of the filler, thus pumping into the engine cylinder. The amount of combustion air and the amount compressed by the replenisher vary.

In order to measure the temperature of the combustion air flowing into the engine 10, a temperature measuring device 47 is arranged in the air inlet duct 14 downstream from the device (which serves to heat the combustion air). The output of the device 47 is coupled to a regulating device (not shown) which regulates the engine as a whole, for example to adjust the overfilling of fuel or the timing of ignition or injection.

The advantages of each embodiment are thus improved exhaust gas emissions and fuel consumption under all operating conditions, as well as increased torque and maximum power. In the case of diesel engines, the ability to start from cold is improved and the noise during cold starting is improved during the preparatory stage. In particular, the emission of solid particles is reduced. The reason is that in operating situations with excessive exhaust gas temperatures, the increase in combustion air temperature is reduced due to a low compression ratio, and in operating situations with excessively low operating temperatures, the combustion air temperature increases, respectively This is because it approaches the value.

Also, in the case of gasoline engines, the tendency to knock at low speeds is reduced because the incoming combustion air temperature is reduced at lower compression ratios.

The temperature of the combustion air or the temporal and spatial temperature changes of the combustion air, the fuel molecules and the reaction products that occur during residence in the combustion chamber of the engine are not static, but have extremely variable dynamic changes in quantity. When entering the combustion chamber at the beginning of the intake stroke, at the inlet temperature, the molecules are at their lowest temperature state. During the compression stroke, the temperature increases considerably, and again during combustion the temperature increases rapidly. Also during the working stroke, the temperature decreases and reaches a value called the exhaust gas temperature when leaving the combustion chamber. In this way different temperatures are applied to different parts of the combustion chamber.

Temperature changes within the high temperature range, immediately before and during the expansion stroke, and during the working stroke have important implications for setting the amount of combustion, i.e. fuel consumption and exhaust gas emissions. ing.

Three temperatures are important in this case.

(a) Final compression temperature which influences mixture formation and formation of hydrocarbons, soot; (o) Combustion temperature which significantly influences the formation of NOx; (c) Oxidation of previously unburnable fuels (TLC and soot). Working gas temperature affects.

Compared to normal variations in the combustion air, it is desirable to keep the final compression temperature high so as to keep the formation of soot and non-combustible hydrocarbons low in order to improve the preparation of the mixture. The combustion temperature should be reduced in order to keep the formation of NOx low, especially during the engine warm-up phase. For engines with low loads, especially in cold conditions, the working gas temperature should be kept high to dispose of non-flammable hydrocarbons and soot.

The treatment according to the invention of the combustion air before it enters the combustion chamber of the engine is achieved by acting on a change in temperature within the combustion chamber. In this case, the operation is carried out taking into account the different conditions of diesel engines and gasoline engines.

For example, when starting a diesel engine from cold, the compression temperature can be increased by heating the combustion air and the associated initial change in temperature to reduce the excess of fuel required for ignition. can.

As a result, the soot generated is reduced in terms of hydrocarbons. A car with higher compression temperatures will also have less ignition lag, less fuel will explode at ignition, lower combustion temperatures and pressures, and less NOx formation.

In an embodiment, the working gas temperature is increased to the same extent as the final compression temperature increases, and a portion of the soot that is formed is disposed of, producing a beneficial effect on the emission. On the other hand, for example at partial load, at the same final compression temperature, by throttling the combustion air flow, the combustion temperature and the working gas temperature will increase if the air surplus is reduced. Even at low ambient temperatures, normal operation will occur if the flow rate of combustion air is reduced.

In the case of gasoline engines, a reduction in compression at part-load conditions with a cold start results in a deterioration of combustion, which is supplemented or over-replenished by heating the combustion air. In the case of overfilling, increasing the air coefficient is advantageous for exhaust gas emissions and fuel consumption.

As described above, in each of the embodiments, in the case of a gasoline engine, the combustion air can be heated when the engine is started from a cold state, and the air coefficient can be increased when running under a partial load condition. Furthermore, in each embodiment, the temperature of the combustion air can be varied by heat dissipated from the engine by heat exchange, so that the heat exchanger is supplied with heat dissipated, for example, from the radiator water of the engine. Instead of or together with this radiator water, the heat exchanger may be supplied with heat dissipated from the engine exhaust gas.

According to a further preferred embodiment of the present invention, the heat dissipated from the engine is indirectly supplied to the combustion air via a heat storage device, in particular a latent heat storage device, so that even when starting from a cold state,
There will be heat heating the combustion air. Also according to a particularly preferred embodiment of the invention, the flow of combustion air is divided into a part flowing through a heat exchanger and a part flowing through a heat storage device, the temperature of the combustion air being different between the two flow parts. is set by controlling the

Further benefits can be obtained by increasing the temperature of the combustion air before it enters the engine, as well as by using a charger.

When starting a diesel engine, in addition to the temperature increase,
It is desirable to also increase the amount of air by using a filler. This is because more fuel can be burned and startup time can be shortened.

By squeezing this filler, the temperature can be further increased and the squeezing effect of the filler can be adjusted.

If the charger is used only as an aid to starting the diesel engine, the displacement charger is deactivated at the end of the start-up phase and the drive of the charger is interrupted or the charger air inlet is turned off. , which is coupled to the atmosphere after this start-up phase.

According to a particularly advantageous embodiment of the invention, the phase relationship of the direct afterfill filler is set for maximum filling efficiency during start-up and other operating phases adapted to the desired combustion gas temperature. If the charger is used to increase torque or power, the combustion gas temperature can be adjusted by inserting the charger during operation with a variable throttling effect that changes the air flow rate over the entire operating range. It will be done.

If the filling device used is of the displacement type, its phase relationship is such that it is synchronized with the movement of the engine piston, so that an advantageous development of the invention provides for example EP 0 126
A method such as that shown in No. 465 is used. In this case, direct post-filling is carried out which varies in phase with respect to the adjustment of flow rate and compression temperature.

When using direct post-filling for a diesel engine during start-up, the phase relationship is set to a maximum charging effect condition that provides a corresponding increase in combustion air temperature for a high air flow rate. These favorable conditions during start-up are made even more satisfactory by heating the combustion air with heat from the heat storage device. By heating the engine continuously, the charging force and heating of the combustion air are adapted to the respective operating phase.

In the case of low partial loads, the charging force is considerably reduced and the heating of the combustion air is maintained at a suitable level, while in the case of full engine load the charging force and the air quantity are at a maximum, so that the air The heating device is turned off or replaced with a charged air cooling condition.

Particularly in the case of gasoline engines, by heating the combustion air before it enters the combustion chamber, combustion air is used more effectively at part-load, reducing air volume and charge change operations. .

The heating of the combustion air is also preferably combined with the so-called Miller effect, so that by early closing the inlet the flow rate is controlled and at the same time the combustion air is expanded and cooled. Although this cooling generally increases toxic exhaust gas emissions, by preheating the combustion air this effect is counteracted and at the same time benefits the charge change operation.

In a preferred embodiment of the invention, at the end of the start-up phase and the preparatory phase, an indication is provided when the temperature in the vicinity of the combustion chamber reaches a predetermined value. This display deactivates the filler and
Alternatively, it is possible to make changes in the phase relation compared to the start-up or preparatory phase, and if necessary, the combustion air heating device provided instead or in addition can be modified accordingly.

In the case of diesel engines, there is a characteristic metallic combustion noise, which is also called cold starting noise in the starting phase, in which the engine temperature is low. Since this phenomenon indicates that the starting phase is still in progress, a knock sensor can be provided whose noise at the end of the cold starting outputs a control signal indicating the end of the starting phase.

In another preferred embodiment of the invention, the end of the start-up phase may be indicated by a timer activated at the beginning of the start-up phase. In order to detect the end of the start-up phase, it is also possible to measure the combustion air temperature or the exhaust gas temperature before the air enters the combustion chamber.

To reduce the compression of an existing engine, the combustion chamber may increase its dimensions without affecting emissions, and the end position of the inlet is reset to occur at a later point in time, thereby The effective amount of travel is reduced during compression, and the amount of travel can be reduced while remaining unchanged, such as by reducing the piston stroke.

All three possibilities, which differ significantly in terms of method effectiveness, can be combined together. However, according to a particularly advantageous embodiment of the invention, when the method is applied to a given engine, the end position of the inlet is reset to a later point in time in order to reduce the compression ratio to a desired value. Set.

In order to take advantage of the advantages that are the useful effects of the method of the invention, it is necessary to have access to engines with compression ratios that are reduced below the usual values for gasoline and diesel engines. Compression ratio is a fundamental design characteristic of an engine. Developing new institutions requires a large amount of work. The design of the combustion chamber in particular shows the result of many years of optimization work. Anything that affects the geometry of the combustion chamber should be eliminated as much as possible to avoid the necessary time spent on development work. By applying the method of the invention, it is clearly possible to reduce the compression ratio by reducing the piston stroke without changing the geometry of the combustion chamber. However, it sacrifices the stroke length on the expansion stroke side, which compromises the engine's actual characteristics and takes time to develop.

By adjusting the timing of inlet closure, the effective compression ratio can be reduced without adversely affecting the valuable features of a successful engine.

The difference between the volume wiped by the piston during expansion and the smaller volume wiped by the piston during compression can be used as additional expansion energy.

Although it is a well-known fact that it is advantageous to adjust the timing of the inlet end position of an internal combustion engine, it has heretofore been employed only to change the torque-speed characteristics of a gasoline engine. Therefore, a reduction in compression ratio has to be tolerated and has been accepted as an unavoidable drawback that may increase fuel consumption. Normally the opening of the outlet is forward in this case, so that the compression and expansion strokes are generally kept unchanged. In diesel engines, the compression ratio is in no case corrected for the necessary lick during cold starting.

To the contrary, the present invention allows for the timing of the inlet closing to be at a particularly later point in time, thereby causing the disadvantages previously present in the compression ratio for a given engine. the reduction is removed.

If an existing engine design is not taken as a starting point,
Engines carrying out the method of the invention are designed such that the effective compression stroke set by the closing of the inlet is much smaller than the effective expansion stroke created by the opening of the outlet. Among the possibilities for the geometrical displacement, it is advantageous if the geometrically available displacement is used for the expansion stroke and the combustion chamber volume is therefore kept to smaller dimensions, which results in partial loads. Offering advantages in range.

In order to prevent loss of heat transferred to the combustion air, the intake manifold supplying the combustion air to the engine cylinders is preferably designed with a small heat capacity.

The manifold is thermally insulated, for example of the type of ceramic-coated double-walled metal sheet construction, and the space therebetween is evacuated if necessary.

(Effects of the Invention) As described in detail above, in the method of the present invention, the optimum combustion air temperature corresponding to the driving conditions of the internal combustion engine is set before the air for twisting is sent into the combustion chamber of the internal combustion engine. Based on the changes, the atmospheric conditions for the combustion air are set, so
Exhaust gas emissions are reduced, wasteful consumption of fuel is prevented, and efficient ignition is possible during cold starts.

[Brief explanation of the drawing]

1 to 8 are explanatory diagrams showing the configuration of an internal combustion engine used in the first to eighth embodiments of the present invention, respectively. DESCRIPTION OF SYMBOLS 10... Engine, 11... Cooling device, 12... Filter, 13... Heating device, 15... Refrigerant circuit, 17
...Radiator circuit, 22... Heat storage device, 26...
・Vehicle heating device, 31... Heat exchanger, 64, 70...
·Heat exchanger.

Claims (6)

[Claims] (1) In a method for driving an internal combustion engine in which the compression ratio can be set to the lowest value suitable for the preparatory operating conditions of the engine, the compression ratio is set to the lowest value suitable for the preparatory operating conditions of the engine, and before the combustion air is sent into the combustion chamber of the internal combustion engine, A method for driving an internal combustion engine, characterized in that atmospheric conditions for the combustion air are set based on a corresponding optimum combustion air temperature change. (2) The method for driving an internal combustion engine according to claim (1), wherein the atmospheric condition is at least one of temperature and flow rate. (3) The internal combustion engine according to claim (2), wherein the temperature of the combustion air is controlled by a heat exchanger based on heat from cooling water of the internal combustion engine or exhaust gas of the internal combustion engine. driving method. (4) Claim (2) is characterized in that the temperature of the combustion air is controlled by a heat exchanger and a heat storage device based on heat from cooling water of the internal combustion engine or exhaust gas of the internal combustion engine. How to drive an internal combustion engine. (5) In an internal combustion engine in which the compression ratio can be set to the lowest value suitable for the preparatory operating conditions of the engine, before combustion air is sent into the combustion chamber of the internal combustion engine, the compression ratio is set to the lowest value that corresponds to the driving conditions of the internal combustion engine. An internal combustion engine comprising: an atmosphere condition setting means for setting an atmosphere condition of the combustion air based on a change in the combustion air temperature. (6) The internal combustion engine according to claim (5), wherein the atmospheric condition setting means sets at least one of temperature and flow rate.