JP3951558B2 - Internal combustion engine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to an improvement of a four-stroke cycle spark ignition internal combustion engine, for example for automobiles, in particular the operating range.InThe present invention relates to a technique for controlling and supplying a plurality of fuel usage ratios accordingly.
[0002]
[Prior art]
  Examples of means for supplying a plurality of fuels to a conventional internal combustion engine include the following. As a first conventional technique, Japanese Patent Application Laid-Open No. 6-10787 discloses a technique for injecting two types of fuel, main fuel and auxiliary fuel, with one nozzle. According to this example, the nozzle tip is filled with the auxiliary fuel, and the auxiliary fuel is injected prior to the injection of the main fuel.TheCan be injected. With this mechanism, it is possible to supply two types of fuel to the engine with one nozzle.
[0003]
As a second prior art, Japanese Patent Laid-Open No. 6-307307 discloses a method for controlling the injection ratio of two fuels from the same inventor. By using alcohol as the first fuel and light oil as the second fuel, and controlling the filling amount at the nozzle tip of the light oil of the second fuel, the mixing ratio of the first fuel and the second fuel is controlled. ing.
[0004]
In such a conventional plurality of fuel supply means, it is necessary to individually supply the first fuel and the second fuel to the dedicated fuel tank from the outside of the vehicle, and the functions of the respective fuels are different. . For example, in Japanese Patent Laid-Open No. 6-307307, in order to improve the ignitability of a diesel engine using alcohol as a main fuel, light oil having better ignitability than alcohol is first injected as an auxiliary fuel. As a result, the light oil is first ignited by compression, and the flame is ignited by alcohol, whereby combustion is performed.
[0005]
In this conventional example, for example, a certain amount of the light fuel of the second fuel may be supplied to improve the ignitability, and the consumption amount of the alcohol of the first fuel changes in the driving state, but both of them are from outside the vehicle. Since the fuel is supplied independently, as in the case of normal refueling, if any one of the remaining amount falls below a certain level, it is replenished at that time.
[0006]
[Problems to be solved by the invention]
Here, in a gasoline engine that can switch between compression self-ignition combustion and spark ignition combustion according to the operating range determined by the engine speed, load, etc., compression self-ignition combustion with excellent fuel economy and exhaust purification is performed. Consider expanding the operating range.
[0007]
In gasoline engines, if the cylinder pressure and the cylinder temperature near the compression top dead center are increased to a certain extent by increasing the internal EGR and compression ratio, the mixture in the combustion chamber is activated and very ignited. Even if spark ignition is not performed, ignition is performed from a plurality of points in the entire combustion chamber and combustion spreads rapidly. As a result, even when the air-fuel ratio is made lean, the combustion period is not prolonged as compared with spark ignition, and stable combustion at a leaner air-fuel ratio is possible. Further, since the air-fuel ratio is lean, the combustion temperature is lowered and NOx can be greatly reduced.
[0008]
However, self-ignition combustion is strongly affected by the air-fuel ratio, knocking occurs on the rich side and the sound vibration characteristics are deteriorated, and combustion stability is lowered on the lean side and torque fluctuations or rotation fluctuations occur to deteriorate operability. . For this reason, in a self-ignition combustion gasoline engine that uses gasoline with a constant octane number, the sound vibration limit due to knocking becomes the rich limit of the air-fuel ratio, the torque fluctuation limit due to deterioration of combustion stability becomes the lean limit of the air-fuel ratio, and the stability The air-fuel ratio range between the limit and the knocking limit is the self-ignition establishment range.
[0009]
In order to expand this self-ignition combustion range, on the rich side of the air-fuel ratio, high-octane fuel is used to suppress knocking, and the knocking limit is further moved to the rich side. It is conceivable that self-ignition is easily caused by using fuel and the combustion stability limit is further moved to the lean side.
[0010]
To simply satisfy the conflicting requirements for the octane number in the driving range, the vehicle is equipped with two gasoline tanks, each of which is filled with different octane numbers of gasoline, and from these two fuel tanks to the driving range. It is conceivable to switch the gasoline with a corresponding octane number and supply it to the engine.
[0011]
However, the provision of two types of fuel filler, fuel tank, and fuel pump system in the vehicle not only raises the manufacturing cost, but also doubles the labor of refueling, resulting in a great burden on the user.
[0012]
Furthermore, where the above driving range is used depends on the driving conditions and the characteristics of the driver, which of the two types of gasoline with different octane numbers is consumed more depends on driving, and cannot be predicted. It is extremely difficult to use gasoline with different octane numbers in a balanced manner. For this reason, there is a problem that even if one of the gasolines remains, if the other gasoline remaining amount is low, refueling must be performed, and the frequency of refueling increases.
[0013]
The present invention has been made by paying attention to such conventional problems, and its problem is to expand an operating range in which compression self-ignition combustion is possible, and to provide an internal combustion engine excellent in fuel economy and exhaust purification. Is to provide.
[0014]
Another object of the present invention is to provide an internal combustion engine that can perform self-ignition combustion in an operating region where high-octane fuel is required and an operating region where low-octane fuel is required only by supplying one type of fuel to the vehicle. It is to be.
[0015]
A further object of the present invention is to provide an internal combustion engine that efficiently uses the supplied fuel and does not increase the frequency of fuel supply.
[0023]
[Means for Solving the Problems]
  Claim1In order to solve the above problems, the described inventionAll load regions where the engine speed is equal to or higher than the medium speed and high load regions where the engine speed is less than the medium speed are the spark ignition combustion method, the engine speed is less than the medium speed, and the medium and high load region. (Region B), Medium-low load region (Region A2), and Low load region (Region C)In an internal combustion engine capable of switching between a self-ignition combustion system and a spark ignition combustion system in accordance with an operating state, a fractionation means for fractionating gasoline fuel supplied to a vehicle into a plurality of fuel components, and the fractionation means A plurality of sub-tanks that respectively store the plurality of fuel components, and a fuel supply device that supplies the plurality of fractionated fuel components at different usage ratios according to operating conditions. In the self-ignition areaDuring ~High loadRegion (region B)ThenHigh boiling pointIncrease the fuel component usage ratio and reduce the load on the self-ignition areaRegion (region C)ThenLow boiling pointIncrease the fuel component usage ratio,In the self-ignition areaMedium to low loadRegion (region A2) orIn the spark ignition region, the gist is to perform control so as to increase the use ratio of the fuel component having a large remaining amount in the sub-tank.
[0024]
  Claim2In order to solve the above problems, the described inventionAll load regions where the engine speed is equal to or higher than the medium speed and high load regions where the engine speed is less than the medium speed are the spark ignition combustion method, the engine speed is less than the medium speed, and the medium and high load region. (Region B), Medium-low load region (Region A2), and Low load region (Region C)In an internal combustion engine capable of switching between a self-ignition combustion system and a spark ignition combustion system in accordance with an operating state, separation means for separating gasoline fuel supplied to a vehicle into a plurality of fuel components having different octane numbers, and obtained by the separation means A plurality of sub-tanks that respectively store the plurality of fuel components, and a fuel supply device that supplies the plurality of separated fuel components at different usage ratios according to operating conditions, the fuel supply device comprising: In the self-ignition areaDuring ~High loadRegion (region B)Will increase the use ratio of fuel components with high octane number and reduce the load in the self-ignition regionRegion (region C)Then, increase the usage ratio of fuel components with low octane number,In the self-ignition areaMedium to low loadRegion (region A2) orIn the spark ignition region, the gist is to perform control so as to increase the use ratio of the fuel component with a large remaining amount of the sub-tank.
[0025]
  Claim3In order to solve the above problems, the described inventionAll load regions where the engine speed is equal to or higher than the medium speed and high load regions where the engine speed is less than the medium speed are the spark ignition combustion method, the engine speed is less than the medium speed, and the medium and high load region. (Region B), Medium-low load region (Region A2), and Low load region (Region C)In an internal combustion engine capable of switching between a self-ignition combustion system and a spark ignition combustion system in accordance with an operating state, fractionation means for fractionating gasoline fuel supplied to a vehicle into a plurality of fuel components having different octane numbers, and the fractionation A plurality of sub-tanks that respectively store a plurality of fuel components obtained by the means, and a fuel supply device that supplies the plurality of fractionated fuel components in different usage ratios according to operating conditions, The fuel supply system isDuring ~High loadRegion (region B)Will increase the use ratio of fuel components with high octane number and reduce the load in the self-ignition regionRegion (region C)Then, increase the usage ratio of fuel components with low octane number,In the self-ignition areaMedium to low loadRegion (region A2) orIn the spark ignition region, the gist is to perform control so as to increase the use ratio of the fuel component with a large remaining amount of the sub-tank.
[0026]
  Claim4In order to solve the above problems, the invention described in the claimsAny one of claims 1 to 3In the internal combustion engine described above, when the self-ignition operation is continued and the remaining amount of the fuel component having a higher usage ratio in the operation region among the plurality of fuel components is less than the first predetermined amount, or When the remaining amount of the fuel component with the smaller usage ratio in the operation region is larger than the second predetermined amount greater than the first predetermined amount, the fuel component is switched to supply more fuel component with the larger remaining amount. The gist is to switch from self-ignition combustion to spark ignition combustion.
[0027]
  According to a fifth aspect of the present invention, there is provided an internal combustion engine capable of switching between a self-ignition combustion system and a spark ignition combustion system in accordance with an operating state in order to solve the above-described problem. A fractionating means for fractionating the fuel components, a plurality of sub-tanks each storing a plurality of fuel components obtained by the fractionating means, and a usage ratio of the fractionated fuel components according to operating conditions A fuel supply device that supplies the fuel with a variable speed and a shift point control means for changing the shift point of the automatic transmission, an operating region in which the use ratio of the fuel component having a high octane number is increased, and the use of the fuel component having a low octane number The operation range where the ratio is increased and the operation range where any octane fuel component can be used are set, and self-ignition operation continues. When the remaining amount of the sub-tank of the fuel component with the higher ratio becomes smaller than the first predetermined amount, or the remaining amount of the sub-tank of the fuel component with the lower usage ratio in the operation region exceeds the first predetermined amount. When the predetermined amount exceeds 2, the shift point of the transmission is changed.ByUse an operating range where the fuel component usage rate is lower and the output ratio is the same as the output before the change, and the remaining amount of the sub-tank is smaller.Engine speed changesThis is the gist.
[0028]
  Claim6In order to solve the above problems, the invention described in the claims2In the internal combustion engine described,ReportThe gist of the separation means includes a fuel filter that adsorbs the high octane fuel component in the fuel and a heater that vaporizes the high octane fuel component adsorbed by the fuel filter and separates it from the fuel filter.
[0036]
【The invention's effect】
  Claim1According to the described invention, the fuel supply device that supplies a plurality of fuel components obtained by the separation means from the gasoline fuel supplied to the vehicle while changing the use ratio according to the driving state is provided in the self-ignition region.During ~High loadRegion (region B)ThenHigh boiling pointIncrease the fuel component usage ratio and reduce the load on the self-ignition areaRegion (region C)ThenLow boiling pointIncrease the fuel component usage ratio,In the self-ignition areaMedium to low loadRegion (region A2) orIn the spark ignition region, by controlling to increase the usage ratio of the fuel component with a large remaining amount in the sub-tank, the fuel suitable for the operation region can be used, the fuel consumption can be improved, and the exhaust gas can be reduced. It is possible to prevent the remaining fuel component from remaining.
[0037]
  Claim2According to the described invention, the fuel supply device that supplies a plurality of fuel components obtained by the separation means from the gasoline fuel supplied to the vehicle while changing the use ratio according to the driving state is provided in the self-ignition region.During ~High loadRegion (region B)Will increase the use ratio of fuel components with high octane number and reduce the load in the self-ignition regionRegion (region C)Then, increase the usage ratio of fuel components with low octane number,In the self-ignition areaMedium to low loadRegion (region A2) orIn the spark ignition area, by controlling to increase the usage ratio of the fuel component with a large remaining amount in the sub-tank, it is possible to use fuel suitable for the operation area, improve fuel efficiency, reduce exhaust gas, and eventually It is possible to prevent the remaining fuel component from remaining.
[0038]
  Claim3According to the present invention described above, the fuel supply device that supplies a plurality of fuel components having different octane numbers obtained from the gasoline fuel supplied to the vehicle by the fractional distillation means at different usage ratios according to the operating state is provided by self-ignition. TerritoryDuring ~High loadRegion (region B)Will increase the use ratio of fuel components with high octane number and reduce the load in the self-ignition regionRegion (region C)Then, increase the usage ratio of fuel components with low octane number,In the self-ignition areaMedium to low loadRegion (region A2) orIn the spark ignition area, by controlling to increase the usage ratio of the fuel component with a large remaining amount in the sub-tank, it is possible to use fuel suitable for the operation area, improve fuel efficiency, reduce exhaust gas, and eventually It is possible to prevent the remaining fuel component from remaining.
[0039]
  Claim4According to the invention described, the claimsAny one of claims 1 to 3In addition to the effects of the described invention, when the self-ignition operation is continued and the remaining amount of the fuel component having the higher usage rate in the operation region among the plurality of fuel components is less than the first predetermined amount, Alternatively, when the remaining amount of the fuel component with the smaller usage ratio in the operation region is larger than the second predetermined amount that is larger than the first predetermined amount, the fuel component with the larger remaining amount is supplied. And switching from self-ignition combustion to spark ignition combustion can prevent underflow or overflow of a plurality of sub-tanks stored for each separated or fractionated fuel component.
[0040]
  According to the fifth aspect of the present invention, in an internal combustion engine capable of switching between the self-ignition combustion system and the spark ignition combustion system in accordance with the operating state, the operating range in which the use ratio of the fuel component having a high octane number is increased, and the octane number The operation range where the use ratio of low fuel components is increased and the operation region where any octane fuel component can be used are set, and self-ignition operation is continued. When the remaining amount of the sub-tank of the fuel component with the higher ratio becomes smaller than the first predetermined amount, or the remaining amount of the sub-tank of the fuel component with the lower usage ratio in the operation region exceeds the first predetermined amount. When the predetermined amount exceeds 2, the shift point of the transmission is changed.ByUse the operating range where the output ratio is the same as the output before the change and the usage rate of the fuel component with the lower sub-tank remaining amount is lower.Engine speed changesThus, the fuel with the larger remaining amount can be used without impairing drivability such as acceleration characteristics with respect to the depression amount of the accelerator pedal.
[0041]
  Claim6According to the invention described, the claims2In addition to the effects of the described invention,ReportThe separation means includes a fuel filter that adsorbs the high-octane fuel component in the fuel and a heater that vaporizes the high-octane fuel component adsorbed by the fuel filter and separates the fuel component from the fuel filter. To separate fuel components from low octane fuel componentsMinutesThe separating means can have a simple structure.
[0042]
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be described below with reference to the drawings.
FIG. 1 is a system configuration diagram showing an embodiment of an internal combustion engine according to the present invention, and shows an example in which the present invention is applied to a gasoline engine.
[0043]
In FIG. 1, a gasoline engine is supplied from an electronic control unit (hereinafter abbreviated as ECU) 1 that controls the entire engine and a fuel usage ratio, a main gasoline tank 8 that is externally supplied with gasoline, and a main gasoline tank 8. And a fractionator for separating the gasoline to be separated into a high-octane fuel having a high boiling point and a high octane number and a low-octane fuel having a low boiling point and a low octane number, and a fractionated high-octane fuel Sub fuel tanks 10 and 11 for storing low-octane fuel, fuel gauges 12 and 13 provided in the sub-tanks 10 and 11, high-pressure intermittent pump 16 for intermittently sending high-octane fuel at high pressure, low Variable pressure pump 15 for delivering octane fuel at a desired constant pressure, output line pressure of variable pressure pump 15 A fuel line pressure gauge 14 to be detected, a fuel injection valve 17 to which fuel is supplied from a variable pressure pump 15 and a high-pressure intermittent pump 16, an ignition plug 18, a variable valve timing mechanism 19, an engine body 20, and an automatic transmission 21 are provided. ing.
[0044]
The ECU 1 includes an operation region determination unit 2 that determines an operation region based on engine load and rotation speed, a fuel mixture ratio determination unit 3 that determines a use ratio or a mixture ratio of high-octane fuel and low-octane fuel, and an operation region. In order to realize the corresponding combustion conditions, the valve timing control unit 4 that controls the valve timing variable mechanism 19, the high-pressure intermittent pump control unit 5 that controls the high-pressure intermittent pump 16, and the variable pressure pump control unit that controls the variable pressure pump 15 6 and an automatic transmission control unit 7 for controlling the shift point of the automatic transmission 21.
[0045]
The variable valve timing mechanism 19 is a mechanism for changing the opening and closing timings of the intake valve and the exhaust valve provided in the engine 20. As the variable valve timing mechanism 19, for example, a mechanism disclosed in Japanese Patent Laid-Open Nos. 9-242520 and 2000-73797 can be applied.
[0046]
The variable valve timing mechanism 19 controls the internal EGR amount by providing a period during which both the intake valve and the exhaust valve are closed by closing the exhaust valve in the middle of the exhaust stroke and closing the intake valve in the middle of the intake stroke. Or, an operation such as lowering the substantial compression ratio of the engine 20 by delaying the closing timing of the intake valve is performed.
[0047]
Next, the operation of the present embodiment will be described.
A fractionator 9 is connected to a main gasoline tank (hereinafter simply referred to as a main tank) 8 through a fuel pipe. The fractionator 9 is provided with, for example, a high-temperature cooling water path from the engine to the radiator and a low-temperature cooling water passage 22 from the radiator to the engine as a high-temperature heat source and a low-temperature heat source (cold heat source). Then, the gasoline component having a high boiling point and the gasoline component having a boiling point lower than the same temperature are separated by the temperature of the high-temperature cooling water, and the gasoline evaporated by the low-temperature cooling water is liquefied again.
[0048]
For example, when the temperature of the cooling water after warming is 80 ° C., it is separated into a component that evaporates at a temperature higher than 80 ° C. (high boiling component) and a component that evaporates at a temperature lower than 80 ° C. (low boiling component). The More specifically, when RON (Research Method Octane Number) 100 gasoline is fractionally distilled at 80 ° C., RON 108 has a high octane number, high molecular weight, high boiling point gasoline component (high octane number fuel) of about volume and the original gasoline. 45% is obtained, and the low-octane number low-boiling gasoline component (low-octane fuel) of RON 94 having a low molecular weight is obtained 55% of the original gasoline volume. At this time, the total gasoline fraction is set to be larger than the amount of gasoline consumed at the maximum load of the engine.
[0049]
In addition, instead of liquefying vaporized gasoline with low-temperature cooling water, it may be liquefied by air cooling, and as a high-temperature heat source, exhaust heat after warming up instead of high-temperature cooling water, and also during cold before warming up, It is also possible to use an electric heater or the like that uses battery power as a high-temperature heat source.
[0050]
The high-octane fuel and the low-octane fuel separated by the fractionator 9 are stored in the respective sub tanks 10 and 11 connected to the fractionator 9. Respective fuel tanks 12 and 13 are provided in the respective sub tanks 10 and 11, and a signal corresponding to the remaining amount of each fuel component is sent to the ECU 1. The high-octane fuel in the sub-tank 10 is supplied with pressure by the high-pressure intermittent pump 16 and the low-octane fuel from the sub-tank 11 is supplied to the single fuel injection valve 17 by the variable pressure pump 15.
[0051]
Then, the residual fuel pressure control of the high pressure intermittent pump 16 by the high pressure intermittent pump control unit 5 of the ECU 1 and the pressure control of the variable pressure pump 15 by the variable pressure pump control unit 6 control the supply fuel pressure of these high octane number fuel and low octane number fuel. By controlling, it is configured to control the injection amount per injection of both fuels injected from the fuel injection valve 17, that is, the use ratio or the mixing ratio of both fuels during injection.
[0052]
FIG. 2 is a cross-sectional view illustrating the detailed structure of the fuel injection valve 17.
In FIG. 2, the fuel injection valve 17 includes a valve body 101, a needle valve 102, a spring 103 that biases the needle valve 102 toward the valve closing side, and a check valve 110. The needle valve 102 includes a large-diameter portion 102a that slides up and down in the valve body 101, a tapered portion 102b that follows this, a small-diameter portion 102c that follows, and a conical shape provided at the tip of the small-diameter portion 102c. A cone portion 102d is provided.
[0053]
An injection port 105 is provided at the distal end portion of the valve body 101, and a seat portion 104 that closes the injection port 105 with the needle valve cone portion 102 d in contact with the needle port cone portion 102 d is immediately inside.
[0054]
Further, the valve body 101 includes an upper fuel pool 108 that is an annular space provided around the needle valve taper portion 102b and an annular space portion that is provided around the distal end portion of the needle valve small diameter portion 102c. There is a tip fuel pool 106, a fuel passage 107 whose tip opens to the tip fuel pool 106 and is supplied with low octane fuel from the variable pressure pump via the check valve 110, and a tip is connected to the upper fuel pool 108. A fuel passage 109 is provided that opens and is supplied with high octane fuel from the high-pressure intermittent pump.
[0055]
Here, since the viscosity of the high-octane fuel is higher than that of the low-octane fuel and is relatively excellent in lubricity at high pressure, the needle valve large diameter portion 102a with respect to the valve body 101 of the fuel injection valve 17 with the high-octane fuel is used. Lubricating moving parts such as
[0056]
Further, due to the intermittent high pressure of the high-octane fuel, the fuel pressure in the upper fuel pool 108 acts as an upward force on the needle valve taper portion 102b, overcomes the pressing force of the spring 103, and slides the needle valve 102 upward. The fuel injection valve 17 is opened when the valve cone portion 102 d is separated from the valve body seat portion 104.
[0057]
On the other hand, the low-octane fuel is supplied to the fuel injection valve 17 at a constant pressure that can be controlled by the variable pressure pump 15. At the end of intermittent injection of high-octane fuel, if the supply pressure of the low-octane fuel of the variable pressure pump with respect to the residual pressure is high, a large amount of low-octane fuel accumulates in the tip fuel pool 106, so that the needle valve 102 opens. Since they are injected first, the injection ratio of low octane fuel can be increased.
[0058]
Conversely, if you want to reduce the low-octane fuel injection ratio, lower the octane fuel by reducing the supply pressure of the low-octane fuel so that it is equal to or lower than the residual pressure when the high-octane fuel intermittent injection ends. At the time of injection starting with lift of the lift of the needle valve 102 by high octane number fuel, almost all of the injected fuel becomes high octane number fuel, and the injection ratio of low octane number fuel can be reduced. .
[0059]
Here, the total fuel amount is an injection amount corresponding to the load, which is the sum of the fuel amount to be intermittently injected and the fuel amount to be supplied at a constant pressure. For this reason, the total injection amount is determined by the driver's torque request, but the mixing ratio at that time is desired to be controlled. For this reason, when the total amount is determined, the fuel injection amount of the intermittent injection is determined so as to determine which fuel is to be mixed and injected in accordance with the remaining amount of the two sub-tanks 10 and 11 next. Then, the level of constant pressure is determined.
[0060]
More specifically, the fuel mixture ratio determination unit 3 of the ECU 1 determines the entire injection amount and the injection ratio of both fuels in the fuel injection ratio determination unit 3, and the high-pressure intermittent pump control unit 5 controls according to the determined injection ratio. The residual pressure of the high-pressure intermittent pump 16 or the constant pressure level of the variable pressure pump controlled by the variable pressure pump control unit 6 is controlled.
[0061]
The high-pressure intermittent pump 16 controls the high-pressure pumping period, and this high-pressure pumping period is a period during which the needle valve is opened. As a result, the total fuel of the constant pressure fuel and the intermittently pumped fuel is injected. The amount is determined. That is, the total amount of fuel is determined by the valve opening period of the high-pressure intermittent injection pump. The constant pressure determines the amount of fuel at a constant pressure that accumulates at the tip of the fuel injection valve, so the mixing ratio is determined.
[0062]
In this way, the injection ratio can be controlled by controlling both the amount of fuel intermittently injected and the supply pressure of fuel supplied at a constant pressure. This fuel injection valve may be used for either intake port injection or in-cylinder direct injection.
[0063]
In the present embodiment, a variable valve timing mechanism 19 that can variably control the valve timing of the intake and exhaust valves is provided. For example, the valve timing is changed so that the exhaust valve is closed early in the middle of the exhaust stroke and the intake valve is opened so that it is delayed so that it is in the middle of the intake stroke. It is possible to control such as slowing down the actual compression ratio.
[0064]
As a result, the amount of residual gas can be controlled, and the compression ratio can be controlled, the temperature and pressure necessary for self-ignition can be obtained, and substantial compression can be performed so that spark ignition is possible. It is also possible to lower the ratio.
[0065]
  FIG. 3 shows the operation region division in the present embodiment, that is, the division between the spark ignition region (A1) based on the load and the engine speed and the self-ignition region, and further within the self-ignition region from the high load to the low load side.Medium to high load rangeB andMedium to low load rangeA2 andLow load areaIt is a map showing which fuel is used by dividing into three regions consisting of C. The regions A1 and A2 can be used with either high octane number fuel or low octane number fuel, and any mixing ratio of the two may be used. In the region B, a high octane fuel that is difficult to cause knocking is suitable because of high load, and in the region C, a low octane fuel that is excellent in combustion stability is suitable because of low load.
[0066]
The map in FIG. 3 is referred to by the operation region determination unit 2 of the ECU 1 to determine which operation region.
[0067]
Here, supplementing the self-ignition, the self-ignition region can be divided into the above three regions mainly depending on the magnitude of the load. In the region B on the high load side, the self-ignition range is limited by knocking, so the octane number of the fuel is It is desirable that the compression ratio is relatively high, the compression ratio is relatively low, and the amount of internal EGR that is recirculated with the exhaust gas remaining in the cylinder is also relatively low.
[0068]
On the other hand, in the low load side region C of the self-ignition region, in order to promote the self-ignition of the lean air-fuel mixture, the fuel octane number is relatively low, the compression ratio is relatively high, and the internal EGR amount is also high. A relatively large amount is desirable. The actual compression ratio and the internal EGR amount can be determined by controlling the valve timing variable mechanism 19 from the valve timing control unit 4 of the ECU 1. Furthermore, it is desirable to promote self-ignition by means such as assisting the mixture activation energy by sparks of the spark plug.
[0069]
In the region A2 where the load is intermediate between the region B and the region C, it is desirable that the fuel octane number, the compression ratio, and the internal EGR amount are relatively at intermediate levels. Thus, it is desirable to cause the self-ignition stably by controlling the engine control parameters according to the load.
[0070]
Next, specific valve timings by the variable valve timing mechanism 19 in each of the operation areas A1, A2, B, and C shown in FIG. 3 will be described with reference to the valve timing diagram of FIG.
[0071]
At the time of self-ignition operation in the C region, since self-ignition hardly occurs at the lowest load side, low-octane fuel is used, and the valve timing shown in FIG. Open slowly and take a large amount of so-called minus overlap. As a result, a large amount of the exhaust gas from the previous cycle is supplied as the EGR gas to the next cycle, and the gas temperature in the cylinder is sufficiently increased to facilitate self-ignition.
[0072]
Further, the closing timing of the intake valve is advanced to near the bottom dead center, the geometric compression ratio is set high, the temperature pressure in the cylinder is increased near the top dead center, and self-ignition is facilitated.
[0073]
During self-ignition operation in region B, since the self-ignition region is on the high load side, self-ignition tends to occur suddenly and knocking easily occurs. Therefore, high octane fuel is used and the valve timing shown in FIG. 10 (b) is set. The exhaust valve is closed late and the intake valve is opened early to reduce the so-called minus overlap amount. As a result, a small amount of exhaust gas from the previous cycle is supplied to the next cycle as EGR gas, so that the gas temperature in the cylinder does not become too high, so that self-ignition does not occur suddenly. .
[0074]
Further, the closing timing of the intake valve is set later than the vicinity of the bottom dead center so that the geometric compression ratio becomes low, and the temperature pressure in the cylinder does not rise so much near the top dead center, so that Try to cause ignition slowly.
[0075]
  During self-ignition operation in the A2 area,LowloadregionTherefore, a moderate temperature and pressure field for self-ignition can be realized in the cylinder, and both high and low octane fuels can be used. For this reason, the valve timing shown in FIG. 10 (c) is set, the exhaust valve is closed slightly late, the intake valve is opened slightly early, and the so-called minus overlap amount is set to about the middle of B and C. The amount of exhaust gas supplied to the next cycle as EGR gas is also set to an intermediate level between B and C. Thereby, the gas temperature in a cylinder becomes moderately high, and self-ignition occurs slowly regardless of whether the octane number is high or low.
[0076]
Further, the closing timing of the intake valve is set a little later than the vicinity of the bottom dead center so that the geometric compression ratio is slightly lower, and the temperature pressure in the cylinder is about halfway between B and C near the top dead center. So that self-ignition occurs slowly.
[0077]
During the operation in the A1 region, since it is a spark ignition operation region, it is not necessary to raise the temperature and pressure in the cylinder unlike the self-ignition combustion.
[0078]
For this reason, the valve timing shown in FIG. 10D is set, the exhaust valve is closed late, and the intake valve is opened earlier than the closing timing of the exhaust valve to provide a so-called overlap amount.
[0079]
As a result, the burnt gas of the previous cycle is hardly supplied as EGR gas in the next cycle, and good flame propagation is performed, and the temperature inside the cylinder due to EGR gas is also suppressed from being increased. Knocking is also suppressed.
[0080]
Furthermore, by closing the intake valve close to the bottom dead center and lowering the geometric compression ratio, the temperature pressure in the cylinder is suppressed near the top dead center. Suppresses knocking.
[0081]
Next, the operation of the present embodiment will be described with reference to a flowchart.
FIG. 4 is a flowchart showing a schematic operation of the present embodiment. First, the engine load and rotation speed are read into the ECU 1, and the operation region is any one of A1, A2, B, and C with reference to a map as shown in FIG. 3 stored in advance based on the load and rotation speed. (Step 10, the following step is abbreviated as S). If the operating region is B or C, then the fuel gauges of the two subtanks are read to detect the remaining amounts of the high-octane fuel and the low-octane fuel (S12).
[0082]
Next, it is determined whether or not the remaining fuel amount corresponding to the operation region, that is, the high octane number fuel in the region B, and the low octane number fuel amount in the region C is greater than the minimum value MIN (S14). If it is larger than the minimum value MIN, only the fuel corresponding to the operation region is used (S16), and the process branches to S26 described later in order to set the valve timing according to the operation region.
[0083]
If it is determined in S14 that the remaining fuel amount corresponding to the operation region is MIN or less, the fuel pumps 15 and 16 are controlled to increase the usage rate (mixing rate) of the other fuel (S20), and the fuel corresponding to the operation region is determined. It is determined whether or not increases (S22). If the fuel fraction corresponding to the operation region exceeds the usage amount, the remaining amount of fuel increases, and if the usage amount exceeds the fractionation amount, the remaining fuel amount decreases.
[0084]
In the determination in S22, if the remaining fuel amount corresponding to the operation region has increased, the fuel use ratio at that time is maintained (S24), the operation region is determined (S26), and if the operation region is C, The valve timing of FIG. 10A for self-ignition combustion with increased EGR and high compression ratio is set, and an auxiliary ignition signal for increasing the pre-reaction (active radical generation reaction) of self-ignition combustion is output (S28). ), Return.
[0085]
If it is determined in S26 that the operation region is B, the valve timing of FIG. 10B for self-ignition combustion with reduced EGR and low compression ratio is set (S30), and the process returns.
[0086]
  If it is determined in S22 that the remaining fuel amount corresponding to the operation region has not increased, self-ignition combustionBakedThe fuel pumps 15 and 16 are controlled so that only the other fuel is used in order to switch to the spark ignition combustion because the fuel corresponding to the operation region cannot be used in spite of the region (S32). The normal valve timing is set to the valve timing of FIG. 10D, and a spark ignition signal is output (S34), and the process returns.
[0087]
In the operation region determination of S10, any fuel can be used as long as it is A1 or A2. Therefore, the fuel gauges of the two sub tanks are read, and the remaining amounts of the high octane fuel and the low octane fuel are respectively read. The amount is detected (S40).
[0088]
Next, the remaining fuel amount of each sub-tank is compared with the minimum value MIN (S42), and if only one remaining amount is MIN or less, the pumps 15 and 16 are controlled to use only the other fuel. (S44). Further, if the remaining amount of fuel in both sub-tanks exceeds the minimum value in the determination in S42, the usage ratio of the fuel with the larger remaining amount is increased (S46). Then, the operating region is discriminated (S48), and if it is A1, the process proceeds to S34 to set for spark ignition combustion. If the operation region is A2, the valve timing of FIG. 10C for self-ignition combustion is set (S50), and the process returns.
[0089]
  As described above, control is performed as shown in FIG.InAccordingly, when the remaining fuel amount in the fractionated fuel that is suitable for the self-ignition combustion region B or C is greater than the minimum value, the fuel that is suitable for the operation region is used to reduce the fuel consumption and purify the exhaust gas. be able to. In addition, when the fuel suitable for the operating region cannot be used, the other fuel is used for spark ignition combustion, and in the operating region where either fuel can be used, control is performed so that the fuel with the larger remaining amount is used. By doing so, it is possible to use only one of the fractionated fuels, avoid the remaining of the other fuel, and reduce the effort of refueling the main tank.
[0090]
When comparing the remaining amounts of the two sub-tanks with the MIN values or comparing them with each other, the remaining amount value should be set in consideration of the volume yield of high and low octane fuels obtained by fractional distillation, 45:55. A corrected value may be used. That is, when the indication value of the fuel gauge 12 of the high-octane fuel sub-tank 10 is Qh and the instruction value of the fuel gauge 13 of the low-octane fuel sub-tank 11 is Qr, the effective fuel residual quantity is the high-octane fuel. The remaining amount may be calculated as 0.9Qh, and the low octane number fuel remaining amount as 1.1Qr.
[0091]
5 to 7 are detailed control flowcharts of the present embodiment.
FIG. 5 mainly uses the fuel with the larger remaining amount in the spark ignition combustion region A1 and the medium load self-ignition combustion region A2 that can be used with either high octane fuel or low octane fuel, from the start of control. The control operation to be performed will be described. FIG. 6 illustrates the operation of the high-load self-ignition combustion region B in which the high-octane fuel is suitable, and FIG. 7 illustrates the operation of the low-load self-ignition combustion region C in which the low-octane fuel is suitable.
[0092]
In FIG. 5, first, the rotational speed and the load are detected, and based on this, the operation region is determined with reference to the map as shown in FIG. 3 (S102). When the operation region becomes C (S104), the process proceeds to FIG. When the operation region becomes B (S106), the process proceeds to FIG.
[0093]
When the operating region becomes the region of A1 or A2 that can be used with any fuel (S108), the remaining fuel amount of the two sub tanks is read to detect the remaining fuel amount (S110). Next, it is determined whether both the remaining fuel amounts are greater than the minimum remaining amount (MIN) (S112).
[0094]
If the remaining amount of the high-octane fuel is less than the minimum (S114), the supply pressure of the low-octane fuel by the variable pressure pump is significantly increased from the residual pressure of the high-pressure intermittent pump so that only the low-octane fuel is used (S116). Then, an ignition signal and a variable valve timing mechanism instruction signal are output so as to perform fine adjustment suitable for the region A1 or A2, such as ignition timing, residual gas amount, compression ratio, etc. (S136), and the process returns.
[0095]
If it is determined in S112 that both of the remaining fuel amounts are greater than the minimum remaining amount (S120), the indication values of the remaining amount gauges of the two subtanks are compared (S122). If the remaining amount of the low octane fuel is large (S124), the pressure of the variable pressure pump that controls the supply pressure of the low octane fuel is increased so that the injection ratio of the low octane fuel is increased (S126), and the process proceeds to S136.
[0096]
In the comparison of S122, if the remaining amount of the high octane fuel is large (S128), the pressure of the variable pressure pump that controls the supply pressure of the low octane fuel is reduced so that the injection ratio of the low octane fuel is reduced (S130), and the process proceeds to S136. Move.
[0097]
If the remaining amount of the low octane fuel is smaller than the minimum in the determination of S112 (S132), the pressure of the variable pressure pump that controls the supply pressure of the low octane fuel is controlled so that only the high octane fuel is used. The pressure is lowered below the residual pressure (S134), and the process proceeds to S136.
[0098]
Thus, by controlling the supply pressure of the low-octane fuel with the variable pressure pump in the operating range of A1 or A2 where any fuel can be used, it is possible to increase the usage ratio of the fuel with the larger remaining amount of fuel. .
[0099]
The fuel usage rate, in other words, the injection rate may be set according to a predetermined map, for example, depending on the relative size difference between the remaining amounts of the two tanks. For example, when the difference between the remaining amounts of the two tanks is large, the fuel injection ratio with a large remaining amount may be set to increase.
[0100]
Simultaneously with such fuel switching control, engine combustion control parameters such as ignition timing and valve timing are controlled according to a predetermined map in accordance with the change in the fuel properties as required.
[0101]
Next, in the high-load self-ignition combustion region B in FIG. 3, high octane fuel is suitable. Therefore, if the remaining amount of the sub-tank of high octane fuel exceeds a predetermined minimum level, high octane fuel is mainly injected. Therefore, the constant supply pressure of the low octane fuel is set to be equal to or lower than the residual pressure of the intermittent injection of the high octane fuel.
[0102]
FIG. 6 shows a control flow when in the region B. If there is a long period of time in this operation region B and the residual amount of high-octane fuel is less than a predetermined minimum, the supply pressure at a constant pressure is increased so as to increase the mixing ratio of low-octane fuel. .
[0103]
Correspondingly, sudden combustion similar to knocking occurs during self-ignition as it is, so the valve timing is controlled so that the minus overlap amount is reduced to reduce the residual gas amount, or when the intake valve closes The actual compression ratio is lowered by slowing down the speed. If the residual amount of high octane fuel still does not recover, the constant supply pressure is increased so that only the low octane fuel is injected, and the region B is switched to flame propagation operation by spark ignition.
[0104]
For this purpose, the valve timing is controlled to reduce the amount of negative overlap to reduce the residual gas amount, and to reduce the compression ratio so that knocking does not occur. In addition, when such a parameter takes a long time to be controlled, the ignition timing is adjusted as necessary so that ignition is performed late so that knocking does not occur.
[0105]
In FIG. 6, when the operation region is a high load self-ignition combustion region B in which a high octane number fuel is suitable, first, the remaining fuel amounts of the two sub-tanks are detected (S140). The remaining amount (MIN) is compared (S142). If the remaining amount of the low-octane fuel is less than the minimum (S144), the supply pressure of the low-octane fuel by the variable pressure pump is significantly lowered from the residual pressure of the high-pressure intermittent pump so that only the high-octane fuel is used (S148). ). Then, in order to perform self-ignition combustion, a variable valve timing mechanism instruction signal is output so as to increase the compression ratio so that the residual gas amount increases (S150), and the process returns.
[0106]
In the comparison in S142, if both remaining amounts are larger than the minimum remaining amount (S146), the process proceeds to S148.
[0107]
In the comparison of S142, if the remaining amount of the high octane fuel is less than the minimum (S152), the supply pressure of the low octane fuel by the variable pressure pump is increased so that the injection ratio of the low octane fuel is increased (S154). Next, it is determined whether or not the remaining amount of the high-octane fuel is below the minimum remaining amount (S156). If not (S158), the low-octane fuel is used so that only the low-octane fuel is used. In order to perform spark ignition combustion, the variable valve timing mechanism instruction is set so that the compression ratio is lowered so that the amount of residual gas is reduced in order to perform spark ignition combustion. A signal and an ignition signal are output (S162), and the process returns.
[0108]
If the determination in S156 increases (S164), the injection ratio is maintained as it is (S166), and the self-ignition combustion is performed, so that the compression ratio becomes higher so that the residual gas amount increases. Then, a variable valve timing mechanism instruction signal is output (S168), and the process returns.
[0109]
Next, when the operation region is in the region C of FIG. 3 for a long time, a large amount of low octane fuel used in the low load self-ignition combustion region C is consumed. A control flow in this case is shown in FIG.
[0110]
If the remaining amount of low-octane fuel is higher than a predetermined minimum level, the supply pressure of the variable pressure pump is increased so that the low-octane fuel is mainly injected, and the tip of the fuel injection valve is A large amount of low-octane fuel is occupied so that most of the injected fuel becomes low-octane fuel during injection.
[0111]
Here, when the remaining amount of the low-octane fuel becomes below the minimum, the injection ratio of the high-octane fuel with a large remaining amount is increased. If this is done, self-ignition is unlikely to occur in this region, so other parameters are controlled to facilitate self-ignition. For example, ignition is performed with a spark plug, or the variable valve timing mechanism is controlled to increase the residual gas amount, or the intake valve is closed close to bottom dead center to obtain a substantial compression ratio.
[0112]
If the remaining amount of the low-octane fuel still does not recover, the constant supply pressure of the low-octane fuel is made lower than the residual pressure at the end of the injection of the high-octane fuel that is intermittently injected so that the entire amount of high-octane fuel is injected. At the same time, since it does not self-ignite as it is, spark ignition is performed and the combustion is switched to normal flame propagation. The compression ratio is higher than, for example, 24 so that the air-fuel ratio can propagate through the flame by changing the valve timing so that knocking does not occur, reducing the residual gas amount, and reducing the amount of fresh air sucked in. To be a value.
[0113]
Until the remaining amount of the low-octane fuel sub-tank generated by fractional distillation recovers to a predetermined amount, mainly using high-octane fuel with a large remaining amount in this state, reducing the amount of low-octane fuel used Continue this state.
[0114]
In FIG. 7, when the operation range is a low-load self-ignition combustion region C to which a low octane fuel is suitable, first, the remaining fuel amounts of the two sub-tanks are detected (S170), and both remaining fuel amounts and the minimum amount of fuel are detected. The remaining amount (MIN) is compared (S172). If the remaining amount of the high-octane fuel is less than the minimum (S174), the supply pressure of the low-octane fuel by the variable pressure pump is significantly increased from the residual pressure of the high-pressure intermittent pump so that only the low-octane fuel is used (S178). ). Then, in order to perform self-ignition combustion, a variable valve timing mechanism instruction signal is output so as to increase the compression ratio so that the amount of residual gas increases (S180), and the process returns.
[0115]
In the comparison of S172, if both of the remaining amounts are larger than the minimum remaining amount (S176), the process proceeds to S178.
[0116]
In the comparison of S172, if the remaining amount of the low octane fuel is smaller than the minimum (S182), the supply pressure of the low octane fuel by the variable pressure pump is lowered so that the injection ratio of the high octane fuel is increased (S184). Next, it is determined whether or not the remaining amount of the low-octane fuel has increased below the minimum remaining amount (S186). If not increased (S188), the low-octane fuel is used so that only the high-octane fuel is used. In order to perform the spark ignition combustion, the variable valve timing mechanism instruction signal and the variable valve timing mechanism instruction signal are set so that the compression ratio becomes low so as to reduce the residual gas amount. The ignition signal is output (S192), and the process returns.
[0117]
If it is determined in S186 that it has increased (S194), the injection ratio is maintained as it is (S196), and in order to perform self-ignition combustion, the compression ratio becomes higher so as to increase the residual gas amount. In addition, a variable valve timing mechanism instruction signal is output. More preferably, in order to facilitate ignition of self-ignition combustion, a self-ignition promotion instruction such as an ignition signal is output (S198), and the process returns.
[0118]
Although not shown in the figure, in any operation region, when the remaining amount of each fuel exceeds a predetermined upper limit by the fuel gauge, switching to use that fuel causes excessive fractional distillation. It is possible to prevent the remaining fuel component from accumulating in the sub tank.
[0119]
Alternatively, if the assumed remaining fuel level determined in advance in each operating region is greater than or equal to the lower limit and the remaining fuel level exceeds the upper limit, the fractional distillation by the fractionator is stopped and the fuel Can prevent excessive accumulation in the sub tank.
[0120]
In addition, although not shown in the drawings, in each operation region, when the predetermined assumed remaining fuel amount exceeds the upper limit, the fractional distillation is stopped, and the fractional fuel supplied to the sub tank consumes less in the engine. Therefore, it can prevent that it accumulates too much.
[0121]
In this way, two types of fuels with different octane numbers obtained by fractional distillation are properly used for each engine operating region, and it is determined which fuel is to be injected depending on the residual amount in the sub-tank, and the engine By adjusting the ignition timing and valve timing, two types of fuel with different octane numbers obtained by fractional distillation can be consumed in a well-balanced manner, and each fuel can be consumed in a maximum amount of time in the required operating range. It becomes like this. For this reason, by changing the type of fuel, the opportunity to use the optimum fuel for each operation region increases, and it is possible to obtain the maximum effects such as improvement of fuel consumption and purification of exhaust gas.
[0122]
FIG. 8 shows that when the internal combustion engine of this embodiment is mounted on a vehicle and combined with an automatic transmission (reference numeral 21 in FIG. 1), the remaining amount of high-octane fuel is less than the minimum value, and instead of high-octane fuel. It is a graph which shows the change of the automatic transmission characteristic at the time of using a low octane number fuel.
[0123]
In the figure, a solid line is a normal shift pattern, and a broken line is a shift pattern when high-octane fuel cannot be used. When high-octane fuel cannot be used, the shift point is moved to a higher speed than usual to compensate for torque reduction and obtain the same acceleration characteristics as usual. Although not shown, the shift point is similarly moved to the high speed side on the downshift side.
[0124]
When a continuously variable transmission (CVT) is installed as an automatic transmission instead of a normal automatic transmission, the value of the gear ratio according to the accelerator opening and the vehicle speed is increased to a higher value using a constant coefficient or a control map. By changing, it is possible to compensate for the torque drop when using low-octane fuel instead of high-octane fuel as in the case of a normal transmission.
[0125]
In this way, when combined with an automatic transmission, the speed change characteristic (shift line) is controlled according to the fuel used, and the operating range used by the engine is changed with the same load, without impairing drivability. The plurality of fractionated fuels can be used up and down without excess or deficiency, and the fuel consumption can be improved and the exhaust gas can be reduced.
[0126]
Furthermore, in the above-described embodiment, an example has been described in which the fuel supplied to the vehicle is separated into two types of fuel components and used in accordance with the driving region. It can also be used properly according to the operating area. In this case, a plurality of fractional distillation temperatures are used, a sub tank is provided according to the type of fuel to be separated, and a plurality of fuel injection valves are used or fuel is supplied to the fuel injection valves using a plurality of high-pressure intermittent pumps. Also good.
[0127]
Next, a structural example of the fractionator 9 will be described in detail with reference to a partial cross-sectional view of FIG.
[0128]
The fractionator 9 includes two trays 41 and 42 in a case 40. Each of the trays 41 and 42 has a plurality of small holes, and the fuel that has fallen from the holes is stored in the storage containers 41A and 42A, respectively. The gasoline in the main gasoline tank 8 is supplied between the trays 41 and 42 in the case 40 via the low pressure pump 52. The trays 41 and 42 communicate with each other through a duct 43 disposed in the case 40 in the vertical direction.
[0129]
The upper end of the case 40 is provided with an outlet 45 for taking out low-boiling components of the fuel as a gas. At the lower end of the case 40, an outlet 46 for taking out a high boiling point component contained in gasoline as a liquid is provided. The low boiling point component gas flowing out from the outlet 45 is cooled by the air cooling cooler 47 and flows into the sub tank 11 as liquefied low octane fuel. The high boiling point component liquid overflowing from the lower tray 42 accumulates on the bottom surface of the case 40 via the duct 53, flows out from the outlet 46, and flows into the sub tank 10 as high octane fuel.
[0130]
In order to control the temperature in the case 40, a radiator 48 and an electric heater 49 are provided below the lower tray 42 in the case 40. The coolant of the engine 20 is guided to the radiator 48 through an electronic control throttle 50 controlled by the controller 1. It is also possible to guide the exhaust gas of the engine 20 instead of the coolant.
[0131]
The electric heater 49 generates heat in accordance with electric power supplied from a battery (not shown) mounted on the vehicle. The case 10 is provided with a temperature sensor 51 for detecting an internal temperature, that is, a fractional distillation temperature, and the detected temperature is input to the controller 1 as a signal. The controller 1 maintains the inside of the case 40 at a predetermined fractional distillation temperature by controlling the opening of the electronic throttle 50 and energization to the electric heater 49 based on the temperature detected by the temperature sensor 51.
[0132]
Specifically, since the coolant temperature is low when the engine 20 is started, the fractionation temperature is realized using the electric heater 49. After the engine 20 has been warmed up, the fractionation temperature is maintained by the heat radiation of the radiator 48. The amount of heat released from the radiator 48 is controlled by operating the electronic control diaphragm 50 performed by the controller 1.
[0133]
Thus, if the inside of case 40 is hold | maintained at 80 degreeC, for example, the low boiling-point component with a boiling point of 80 degrees C or less in the gasoline guide | introduced in case 40 will boil and vaporize.
[0134]
The gas having a low boiling point moves upward in the case 40 from the duct 43, partly flows out from the outlet 45, partly contacts the upper tray 41 or the liquid accumulated in the tray 41, and is liquefied. Falls into the storage container 41a. The liquid in the storage container 41a is also boiling, and the gas having a low boiling point component vaporized therefrom also flows out from the outlet 45.
[0135]
On the other hand, the lower tray 42 accumulates high boiling point components in gasoline introduced into the case 40. Then, the high boiling point component liquid overflowing from the tray 42 flows out from the outlet 46 through the duct 53, through the bottom of the case 40. In this way, gasoline is fractionated into a low-boiling component low-octane fuel and a high-boiling component high-octane fuel.
[0136]
A storage tank 12 for detecting the amount of high-octane fuel stored is attached to the sub-tank 10 for storing high-octane fuel, and the detected fuel storage is input to the controller 1 as a signal. 11, a storage amount meter 13 for detecting the storage amount of the low octane fuel is attached, and the detected residual fuel amount is input to the controller 1 as a signal.
[0137]
Next, another embodiment of the present invention relating to the separation of gasoline will be described with reference to FIG.
In this embodiment, gasoline is separated into a high-octane fuel and a low-octane fuel using a separator 120 using silica gel instead of the fractionator 9.
[0138]
When gasoline comes into contact with silica gel, aromatic components having a high octane number in gasoline are adsorbed on silica gel, and the octane number of the remaining gasoline decreases. Separator 120 utilizes this property to separate gasoline into high-octane fuel and low-octane fuel.
[0139]
For example, the separator 120 includes a pair of adsorbers 123 and 124 including filters 121 and 122 mainly composed of silica gel formed in a spherical granular shape. The adsorber 123 includes an electric heater 125 that generates heat with the electric power of the battery 127 via the switch 126. The adsorber 124 includes an electric heater 129 that generates heat with the electric power of the battery 127 via the switch 128.
[0140]
Fuel from a main tank (not shown) is selectively supplied to one of the adsorbers 123 and 124 by the switching valve 130. The fuel that has passed through the adsorber 123 flows via the switching valve 131 into either the sub tank 10 that stores high octane fuel or the sub tank 11 that stores low octane fuel. An air-cooled cooler 133 is provided in the inflow passage to the sub tank 10 that stores the high octane fuel. The fuel that has passed through the adsorber 124 flows into one of the sub tanks 10 and 11 through the switching valve 132.
[0141]
In FIG. 11, the switching valve 130 allows gasoline to flow into the adsorber 124. In this state, the electric heater 129 of the adsorber 124 is not energized. The gasoline that passes through the silica gel filter 122 in the adsorber 124 adsorbs the high-octane aromatic component on the silica gel and flows out of the adsorber 124 as a low-octane fuel. The switching valve 132 guides this low octane fuel to the sub tank 11.
[0142]
On the other hand, the adsorber 123 energizes the electric heater 125 via the switch 126. As a result, the temperature in the adsorber 123 rises, and the high octane aromatic component adsorbed on the silica gel filter 121 is vaporized and desorbed from the filter 121. The desorbed aromatic component is led from the adsorber 123 to the air-cooled cooler 133 through the switching valve 131, cooled and liquefied by the air-cooled cooler 133, and then flows into the sub tank 10 as high-octane fuel.
[0143]
When the desorption of the aromatic component from the filter 121 of the adsorber 123 is completed and the filter 122 of the adsorber 124 has sufficiently adsorbed the aromatic component, the switching valves 130, 131, and 132 are switched. At the same time, switch 126 is turned off and switch 128 is turned on.
[0144]
As a result, the gasoline in the main tank is supplied to the adsorber 123 via the switching valve 130, and after the filter 121 adsorbs the aromatic component in the adsorber 123, it flows from the switching valve 131 to the sub tank 11 as a low octane fuel. . On the other hand, in the adsorber 124, the aromatic component is desorbed from the filter 122 by the heat generated by the electric heater 129. The separated component is guided to the air-cooled cooler 133 via the switching valve 132, liquefied in the air-cooled cooler 133, and then flows into the sub tank 10 as a high octane fuel.
[0145]
In this way, gasoline can be continuously separated into high-octane fuel and low-octane fuel by alternately supplying gasoline to one of the adsorbers 123 and 124 and heating the other. In this embodiment, two types of adsorbers are used, but the adsorption and desorption of aromatic components may be repeated intermittently using only one type, or cyclically using three or more types. Obviously, adsorption and desorption may be repeated.
[0146]
In each of the above embodiments, gasoline is used by separating it into two types of fuel. However, it is also possible to use it by separating it into more types. In this case, for example, the fractionator applies a plurality of fractionation temperatures, and stores them in the same number of subtanks as the types of fuel to be separated. In order to use these fuels properly, a plurality of fuel injectors or a plurality of high-pressure intermittent pumps are used.
[Brief description of the drawings]
FIG. 1 is a system configuration diagram showing the configuration of an embodiment of an internal combustion engine according to the present invention.
FIG. 2 is a cross-sectional view showing a configuration example of a fuel injection valve used in an embodiment of the present invention.
FIG. 3 is a spark ignition fuel in an embodiment of the present invention.BakedIt is a figure which shows the example of the request | requirement octane number in each operation area | region in an area | region, a self-ignition combustion area | region, and a self-ignition combustion area | region.
FIG. 4 is a schematic control flowchart for explaining the schematic operation of the embodiment of the present invention.
FIG. 5 is a detailed flowchart of an embodiment of the present invention, showing the operation of the spark ignition combustion region A1 and the medium load self-ignition combustion region A2.
FIG. 6 is a detailed flowchart of the embodiment of the present invention, and shows the operation in the high-load self-ignition combustion region B.
FIG. 7 is a detailed flowchart of the embodiment of the present invention, and shows the operation in the low-load self-ignition combustion region C.
FIG. 8 is a shift characteristic diagram illustrating shift point control in the embodiment of the present invention.
FIG. 9 is a partial cross-sectional view showing details of a fractionator which is a fuel separation means in the embodiment.
FIG. 10 is a valve timing diagram illustrating valve timing for each operation region in the embodiment.
FIG. 11 is a partial cross-sectional view illustrating a separator using silica gel, which is another embodiment of the fuel separator.
[Explanation of symbols]
1 ECU
2 Operation area judgment part
3 Fuel mixture ratio determination unit
4 Valve timing controller
5 High pressure intermittent pump controller
6 Variable pressure pump controller
7 Automatic transmission controller
8 Main gasoline tank
9 fractionator
10 RON108 sub tank
11 RON94 sub tank
12 Fuel gauge
13 Fuel gauge
14 Fuel line pressure gauge
15 Variable pressure pump
16 High-pressure intermittent pump
17 Fuel injection valve
18 Spark plug
19 Valve timing variable mechanism
20 Engine body
21 Automatic transmission
22 Cooling water passage

Claims (6)

All load regions where the engine speed is equal to or higher than the medium speed and high load regions where the engine speed is less than the medium speed are the spark ignition combustion method, the engine speed is less than the medium speed, and the medium and high load region. (Region B), Medium-low load region (Region A2), and Low load region (Region C) Switch between the self-ignition combustion method and the spark ignition combustion method according to the operating state so that the self-ignition combustion method is used. Possible internal combustion engines,
  Fractionating means for fractionating gasoline fuel supplied to a vehicle into a plurality of fuel components;
  A plurality of sub-tanks each storing a plurality of fuel components obtained by the fractionating means;
  A fuel supply device that supplies a plurality of fractionated fuel components by changing a use ratio according to an operating state;
  The fuel supply device includes:
  In the medium and high load areas (area B) of the self-ignition area, increase the use ratio of fuel components with a high boiling point,
  In the low load region (region C) of the self-ignition region, increase the use ratio of the fuel component with a low boiling point,
  An internal combustion engine that performs control so as to increase a use ratio of a fuel component with a large remaining amount in a sub-tank in a middle / low load region (region A2) or a spark ignition region in a self-ignition region. All load regions where the engine speed is equal to or higher than the medium speed and high load regions where the engine speed is less than the medium speed are the spark ignition combustion method, the engine speed is less than the medium speed, and the medium and high load region. (Region B), Medium-low load region (Region A2), and Low load region (Region C) Switch between the self-ignition combustion method and the spark ignition combustion method according to the operating state so that the self-ignition combustion method is used. Possible internal combustion engines,
  Separation means for separating gasoline fuel supplied to the vehicle into a plurality of fuel components having different octane numbers;
  A plurality of sub-tanks each storing a plurality of fuel components obtained by the separating means;
  A fuel supply device that supplies the plurality of separated fuel components in different usage ratios according to operating conditions;
  The fuel supply device includes:
  In the medium and high load areas (area B) of the self-ignition area, increase the use ratio of fuel components with a high octane number,
  In the low load region (region C) of the self-ignition region, increase the use ratio of the fuel component with a low octane number,
  An internal combustion engine that performs control so as to increase a use ratio of a fuel component having a large remaining amount of a sub-tank in a middle / low load region (region A2) or a spark ignition region in a self-ignition region. All load regions where the engine speed is equal to or higher than the medium speed and high load regions where the engine speed is less than the medium speed are the spark ignition combustion method, the engine speed is less than the medium speed, and the medium and high load region. (Region B), Medium-low load region (Region A2), and Low load region (Region C) Switch between the self-ignition combustion method and the spark ignition combustion method according to the operating state so that the self-ignition combustion method is used. Possible internal combustion engines,
  Fractionating means for fractionating gasoline fuel supplied to a vehicle into a plurality of fuel components having different octane numbers;
  A plurality of sub-tanks each storing a plurality of fuel components obtained by the fractionating means;
  A fuel supply device that supplies a plurality of fractionated fuel components by changing a use ratio according to an operating state;
  The fuel supply device includes:
  In the medium and high load areas (area B) of the self-ignition area, increase the use ratio of fuel components with a high octane number,
  In the low load region (region C) of the self-ignition region, increase the use ratio of the fuel component with a low octane number,
  An internal combustion engine that performs control so as to increase a use ratio of a fuel component having a large remaining amount of a sub-tank in a middle / low load region (region A2) or a spark ignition region in a self-ignition region. When the self-ignition operation is continued and the remaining amount of the fuel component having a higher usage rate in the operation region among the plurality of fuel components is less than the first predetermined amount, or the use rate is increased in the operation region. When the remaining amount of the fuel component of the smaller amount exceeds the second predetermined amount greater than the first predetermined amount, the fuel component is switched to supply more fuel component of the larger remaining amount, and the spark from self-ignition combustion The internal combustion engine according to any one of claims 1 to 3, wherein the internal combustion engine is switched to ignition combustion. In an internal combustion engine that can switch between a self-ignition combustion method and a spark ignition combustion method according to the operating state,
Fractionating means for fractionating gasoline fuel supplied to a vehicle into a plurality of fuel components having different octane numbers;
A plurality of sub-tanks each storing a plurality of fuel components obtained by the fractionating means;
A fuel supply device that supplies the plurality of fractionated fuel components in different usage ratios according to operating conditions;
Shift point control means for changing the shift point of the automatic transmission,
Set the operating range to increase the usage ratio of fuel components with a high octane number, the operating range to increase the usage ratio of fuel components with a low octane number, and the operating range that can be used with any fuel component with an octane number,
When the self-ignition operation is continued and the remaining amount of the sub-tank of the fuel component having the larger usage ratio in the operation region among the plurality of fuel components is less than the first predetermined amount, or the use ratio is increased in the operation region. When the remaining amount of the sub-tank of the smaller fuel component exceeds the second predetermined amount that is larger than the first predetermined amount, by changing the shift point of the transmission , the output equivalent to the output before the change can be obtained. An internal combustion engine characterized in that the engine speed is switched so as to use an operating region in which the usage ratio of the fuel component with the smaller remaining amount of the sub-tank is lower. The separation means includes a fuel filter that adsorbs a high-octane fuel component in the fuel, and a heater that vaporizes the high-octane fuel component adsorbed by the fuel filter and separates it from the fuel filter. Item 3. The internal combustion engine according to Item 2.

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