WO2010064302A1

WO2010064302A1 - Control device for internal combustion engine

Info

Publication number: WO2010064302A1
Application number: PCT/JP2008/071888
Authority: WO
Inventors: 西田　秀之
Original assignee: トヨタ自動車株式会社
Priority date: 2008-12-02
Filing date: 2008-12-02
Publication date: 2010-06-10

Abstract

The amount of injection of emulsion fuel is optimally controlled. An engine (200) has a fuel supply device (300) capable of supplying , as the fuel for a common rail (209), emulsion fuel formed by substantially uniformly mixing, by using a mixer (309), light oil (FL) contained in a main tank (301) and water (WT) contained in a first sub-tank (305). An ECU (100) controls fuel injection. In the process of control of the fuel injection, the ECU (100) calculates the amount of heat generated by water in the fuel by using both the percentage of water content in the fuel and the efficiency of reaction of water. The calculation by the ECU (100) is made according to a preset calculation formula, and the percentage of water content is estimated based on the flow rates of the light oil (FL) and the water (WT) that are detected by flow rate sensors (314, 315). According to the calculated heat generation amount, the ECU (100) corrects a basic fuel injection time (TAU0) previously determined according to operating conditions of a vehicle and calculates an accurate injection time (TAU1) in which the heat generation amount of the water is taken into consideration.

Description

Control device for internal combustion engine

The present invention relates to a technical field of a control device for an internal combustion engine configured to be able to use emulsion fuel.

As an apparatus of this type, an internal combustion engine using light oil and water emulsion fuel is disclosed which determines an engine operation control parameter according to the fuel content (see, for example, Patent Document 1).

According to the control apparatus for an internal combustion engine disclosed in Patent Document 1 (hereinafter referred to as “conventional technology”), the amount of fuel in the emulsion fuel and the fuel content determined according to the fuel content of the emulsion fuel are reduced. The amount of fuel that actually contributes to combustion is calculated from the contribution rate, and the injection timing of main injection or pilot injection is calculated based on the amount of fuel that contributes to combustion. In this case, it is said that suitable combustion is ensured.

Note that Patent Document 2 discloses that hydrogen and oxygen contribute to combustion.

Also disclosed is a technique for controlling the fuel injection amount in accordance with the proportion of water in the fuel in an internal combustion engine having a system for supplying emulsion fuel mixed with light oil and water and a system for supplying normal fuel. (For example, see Patent Document 3).

JP 2004-68619 A JP 2003-343275 A JP-A-63-9939

When the water content in the emulsion fuel is handled in the same way as the main fuel without considering the content ratio of the main fuel (e.g. gasoline, light oil, etc.) in the emulsion fuel, the fuel injection amount satisfies the required output, for example. Less than the appropriate amount that can be determined accordingly. On the other hand, in the above conventional technology, the water in the emulsion fuel is treated as not contributing to combustion, and the fuel injection amount is corrected to the increasing side according to the fuel content ratio. Such a problem does not occur.

However, in reality, water in emulsion fuel is known to contribute to combustion even though the degree of influence is different from that of main fuel, and in the category of technical ideas related to conventional technology, Conversely, the fuel injection amount becomes excessive by the amount of heat generated. That is, the conventional technique has a technical problem that it is difficult to avoid deterioration in fuel consumption and emission due to the deviation of the injection amount of the emulsion fuel from the appropriate value.

In addition, in the conventional technology, water in emulsion fuel originally does not contribute to combustion, so it is only necessary to know the content of main fuel or water in emulsion fuel, but water contributes to combustion. In view of this, it is difficult to accurately determine the fuel injection amount only by grasping this kind of content rate.

The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a control device for an internal combustion engine that can suitably control the injection amount of emulsion fuel.

In order to solve the above-described problems, an internal combustion engine control apparatus according to the present invention is mounted on a vehicle and configured to be able to use an emulsion fuel obtained by mixing a main fuel and a liquid containing at least water, and the emulsion. A control apparatus for an internal combustion engine comprising an injection means capable of injecting fuel, wherein the first heat generation amount specifying means for specifying the heat generation amount of the water in the emulsion fuel, the operating condition of the vehicle and the specified Determining means for determining an injection amount of the emulsion fuel based on a heat generation amount of water; and injection control means for controlling the injection means so that the emulsion fuel corresponding to the determined injection amount is injected. It is characterized by doing.

The “emulsion fuel” according to the present invention refers to a mixed fuel obtained by mixing various main fuels such as light oil or gasoline and various liquids including at least water. The liquid may be water alone or may contain various alcohols such as ethanol in addition to water, and the component ratio (for example, water content ratio or alcohol content ratio) in this emulsion fuel is , It may be fixed or variable.

Here, the water contained in the liquid constituting the emulsion fuel is mainly reduced in combustion temperature due to latent heat of vaporization (that is, reduction in NOx emissions) or promotes atomization of the main fuel due to boiling (increase in smoke emissions due to uniform combustion). For the purpose of reduction, etc., it is mixed with the main fuel, but separately, when it is steamed in a high temperature field, the carbon (C) produced from the fuel is oxidized to generate hydrogen (H2). Since the reaction in which hydrogen is oxidized to produce water (H 2 O) is an exothermic reaction, the amount of heat generated per unit weight of water in the emulsion fuel is lower than that of the main fuel, but is not zero.

Therefore, when water is treated as not contributing at all to the combustion reaction related to vehicle power generation in the combustion chamber, and the injection amount is corrected to the increase side according to the moisture content of the emulsion fuel, the injection amount is the required amount. On the other hand, it becomes excessive by the amount corresponding to the heat generation amount of water, and the emission deteriorates. On the other hand, if the heat generation amount of water is treated as equivalent to the main fuel and the injection amount is not substantially corrected, the injection amount is insufficient with respect to the required amount and the power performance is reduced (strictly speaking, For example, the calorific value of the main fuel is not necessarily larger than the calorific value of water (note that it is of course larger for light oil or gasoline), but in that case, the injection amount becomes excessive with respect to the required amount. Emissions get worse).

That is, it is obvious that water and main fuel are not distinguished at all (that is, a problem before the concept of water calorific value is conceived), and it is simply assumed that the calorific value of water is small enough to be regarded as zero or zero. In any case of the technical concept of correcting the injection amount to the increase side according to the water content ratio (that is, only defining the heat generation amount of water only), the emulsion fuel injection amount cannot be optimized anyway.

On the other hand, according to the control apparatus for an internal combustion engine according to the present invention, during operation, for example, various processing units such as an ECU (Electronic Control Unit), various controllers, various computer systems such as a microcomputer device, etc. The calorific value of water in the emulsion fuel is identified by the first calorific value specifying means that can be used (in the present invention, “specification” is a concept that encompasses detection, estimation, calculation, derivation, identification, acquisition, etc.) As long as the determination means can grasp the specific object (in this case, the amount of heat generated from water) as information that can be referred to in the control, the process may have various aspects. Based on the heat generation amount of the specified water and the driving conditions of the vehicle, for example, various processing units such as an ECU, various controllers, The final injection amount of the emulsion fuel is determined by the determining means that can take the form of various computer systems such as a microcomputer device, for example, the injection amount itself or various control amounts that can directly or indirectly define the injection amount (for example, Injection time). When the injection amount is determined, emulsion fuel corresponding to the determined injection amount is injected by an injection control means that can take the form of various processing units such as an ECU, various controllers or various computer systems such as a microcomputer device. In this way, the injection means such as an electronically controlled injector is controlled.

For this reason, the mixing ratio between the main fuel and the liquid in the emulsion fuel is fixed or variable, but the injection amount is increased according to the heat generation amount of water (the heat generation of the main fuel per unit weight). (If the amount is larger), it is possible to correct or take measures such as determining the injection amount in consideration of the heat generated from the water from the beginning, and optimize the amount of emulsion fuel injected from the injection means It becomes possible to make it.

Such an effect can be obtained regardless of the type of main fuel and the type of liquid. In particular, emulsion fuel is used to prevent a sudden change in the combustion temperature and to prevent fuel from being used. This is remarkable when the injection is performed by so-called multi-point injection divided into a relatively small amount of pilot injection executed one or more times to promote mixing and main injection. That is, since the pilot injection amount is smaller than the main injection amount, it is easily affected by the accuracy of the injection amount. Therefore, combustion performance and NV (Noise and Vibration: noise and vibration) are likely to deteriorate with a relatively low accuracy pilot injection amount determined through an injection amount determination process in which the heat generation amount of water is not sufficiently considered. In that respect, according to the present invention, the pilot injection control accuracy can be improved, so that a transient change in the combustion speed due to misfire or afterburning is suppressed, and emission, power performance, NV performance, etc. can be further improved. It becomes possible.

In one aspect of the control apparatus for an internal combustion engine according to the present invention, the control apparatus further includes a water content specifying means for specifying a water content ratio of the emulsion fuel, and the first heat generation amount specifying means is based on the specified water content ratio. The heat generation amount of water in the emulsion fuel is specified.

According to this aspect, the water content ratio of the emulsion fuel is, for example, a desirable volume ratio by the water content ratio specifying means that can take the form of various processing units such as an ECU, various controllers or various computer systems such as a microcomputer device. Identified as Here, according to the specific concept described above, the water content of the emulsion fuel is the water content or various physical quantities correlated with the water content (for example, the ratio of the main fuel in the emulsion fuel, the liquid constituting the emulsion fuel). Or the water content ratio in the liquid, or the flow rate or flow rate ratio of each fuel constituting the emulsion fuel), and various signals corresponding to the detection results are acquired from detection means such as various sensors. In the case where the emulsion fuel is produced by appropriately mixing the main fuel and the liquid in the vehicle, the emulsion fuel may be specified based on the mixing ratio. Further, when provision of information capable of specifying the water content ratio is received from various infrastructure facilities such as a service station for refueling, the water content ratio may be specified by referring to this type of information.

Here, the maximum calorific value of water per unit weight is determined or can be uniquely defined, and the density difference between the main fuel and water can be defined in advance. The 1 calorific value specifying means can specify the calorific value of water with high accuracy based on the water content of the emulsion fuel. Therefore, according to this aspect, the injection amount of the emulsion fuel can be determined with relatively high accuracy.

In view of the above specific concept, the first calorific value specifying means refers to a control map or the like stored in advance in the appropriate storage means in association with the water content ratio and the heat value of water, and each time the water content is determined. The calorific value of water may be specified by selectively acquiring one value corresponding to the ratio. However, the calorific value of water changes continuously according to the water content ratio, and the control map becomes more complicated if the accuracy of specifying the calorific value of water is improved. Moreover, no matter how complicated the control map is, it is almost impossible to create an infinite number of control maps according to the water content ratio that can be continuously changed in a stepless manner at least within a range in which the effectiveness is ensured. In view of that, the first calorific value specifying means treats the specified water content ratio as one variable of calculation processing as a preferred form, and each time numerical calculation processing based on various algorithms, calculation formulas, etc. Alternatively, the heat generation amount of water may be specified by performing logical operation processing.

In another aspect of the control device for an internal combustion engine according to the present invention, the control device further includes reaction efficiency specifying means for specifying the reaction efficiency of the water in the emulsion fuel, wherein the first heat generation amount specifying means is the specified reaction. Based on the efficiency, the heat generation amount of water in the emulsion fuel is specified.

In emulsion fuel, water constituting the liquid does not always cause the above reaction with a probability of 100%. If the proportion of water that can be subjected to the reaction changes, the heat generation amount of water corresponding to the water content naturally changes. Therefore, in this aspect, the reaction efficiency of water in the emulsion fuel is specified by reaction efficiency specifying means that can take the form of various processing units such as an ECU, various controllers or various computer systems such as a microcomputer device. Here, the “water reaction efficiency” refers to the above-described reaction process. For example, (1) the proportion of water vapor that reacts with carbon to produce hydrogen in the entire water vapor, or (2) produced This refers to the proportion of hydrogen used in combustion reactions, for example, when steam reacts with carbon with a probability of 100% and the generated hydrogen burns with a probability of 100%, standardized as “1” etc. May be specified as a value of 1 or less.

According to this aspect, since the first calorific value identifying means identifies the calorific value of water based on the identified reaction efficiency, it is possible to perform more realistic injection amount control considering the reaction efficiency, It is possible to further optimize the injection amount within the range of realistic restrictions on the driving conditions of the vehicle.

The water reaction efficiency is affected by, for example, the temperature distribution and spatial distribution of water vapor inside the cylinder. Therefore, the reaction efficiency specifying means can reflect the influence of this kind of temperature distribution and spatial distribution according to various driving conditions of the vehicle in advance experimentally, empirically, theoretically or based on simulation or the like. You may specify with the aspect of referring the control map defined.

In another aspect of the control device for an internal combustion engine according to the present invention, the determination means corrects the basic injection amount of the emulsion fuel determined according to the operating condition of the vehicle based on the heat generation amount of the specified water. Thus, the injection amount of the emulsion fuel is determined.

According to this aspect, in determining the final injection amount of the emulsion fuel, the determining means first determines the vehicle operating conditions, for example, the vehicle speed, the accelerator opening, the load factor or the intake air amount, or these various physical amounts, The basic injection amount (which may be determined as the injection time) of the emulsion fuel is determined according to the required output, the required torque, the required driving force or the like that is calculated or determined as appropriate from the control amount or the index value. This basic injection amount is, for example, an injection amount that satisfies the required output of the vehicle when the water content of the emulsion fuel takes an arbitrary fixed value (for example, zero, that is, the emulsion fuel is substantially the main fuel). Unaffected by the physical or chemical state of the emulsion fuel.

According to this aspect, the final injection amount of the emulsion fuel is determined by correcting the basic injection amount in accordance with the heat generation amount of the specified water. Therefore, the control process for determining the injection amount is simplified, and the load on the determining means can be reduced.

In another aspect of the control device for an internal combustion engine according to the present invention, the emulsion fuel includes alcohol as the liquid, and further includes a second calorific value identifying means for identifying the calorific value of the alcohol in the emulsion fuel, The determining means determines the injection amount of the emulsion fuel based on the heat value of the specified alcohol.

According to this aspect, the emulsion fuel contains various alcohols such as ethanol in addition to water as a liquid. For example, the emulsion fuel may take various processing units such as an ECU, various controllers or various computer systems such as a microcomputer device. 2 The calorific value specifying means identifies the calorific value of the alcohol in the emulsion fuel, and the final injection amount is determined based on the calorific value of the alcohol in addition to the calorific value of water. It is possible to optimize the injection amount for the emulsion fuel that can be taken. Alternatively, it is possible to improve the accuracy of the injection amount.

In this aspect, it further comprises alcohol content ratio specifying means for specifying the alcohol content ratio of the emulsion fuel, and the second calorific value specifying means is configured to determine the alcohol content in the emulsion fuel based on the specified alcohol content ratio. The amount of heat generated may be specified.

According to this aspect, the alcohol content ratio of the emulsion fuel, for example, the volume ratio is desirable by the alcohol content ratio specifying means that can take the form of various processing units such as an ECU, various controllers or various computer systems such as a microcomputer device. Identified as one of Here, the maximum calorific value of each alcohol per unit weight is determined or can be uniquely defined, and since the density difference between the main fuel and each alcohol can be specified in advance, The second heat generation amount specifying means can specify the heat generation amount of the alcohol with high accuracy based on the alcohol content of the emulsion fuel. Therefore, according to this aspect, the injection amount of the emulsion fuel can be determined with relatively high accuracy.

In another aspect of the control device for an internal combustion engine according to the present invention, the control device further includes a temperature specifying unit that specifies the temperature of the emulsion fuel, and the determining unit is configured to inject the emulsion fuel based on the specified temperature. To decide.

According to this aspect, for example, the temperature of the emulsion fuel is specified by temperature specifying means that can take the form of various processing units such as an ECU, various controllers or various computer systems such as a microcomputer device, etc. The “emulsion fuel temperature” may include the temperature of the main fuel or the liquid constituting the emulsion fuel), and the determining means may add to the calorific value of water or, in some cases, the calorific value of various alcohols, The injection amount of the emulsion fuel is determined based on the specified temperature. For this reason, according to this aspect, it becomes possible to correct an error in the calorific value due to changes in the density of the main fuel and / or liquid depending on the temperature, and optimally maintain the injection quantity regardless of the environmental conditions of the vehicle. It becomes possible to do.

In another aspect of the control device for an internal combustion engine according to the present invention, the vehicle further includes a generating means capable of generating the emulsion fuel by mixing the main fuel and the liquid, and the control device for the internal combustion engine. Further comprises generation control means for controlling the generation means so that the main fuel and the liquid are mixed at a desired mixing ratio.

According to this aspect, the internal combustion engine includes, for example, various pipes that feed each fuel from a supply source of each fuel, various pump devices that can be appropriately installed in the pipe, regardless of whether they are electric or mechanical, and in the pipe Physical and mechanical components that allow mixing of the main fuel and the liquid, which may appropriately include various valve devices capable of controlling the communication state of the above and a mixer for appropriately mixing the various pipes and mixing the corresponding fuel, Generation means as a concept encompassing electrical, magnetic or chemical means are provided.

According to this aspect, the main fuel and the liquid are mixed at a desired mixing ratio by the generation control means that can take the form of various processing units such as an ECU, various controllers or various computer systems such as a microcomputer device. This generating means is controlled. For this reason, for example, the condition that the mixing ratio of the main fuel should be increased if the remaining amount of liquid is small, and conversely the mixing ratio of the liquid should be increased if the remaining amount of main fuel is small, or the economy should be emphasized over the power performance. It is also possible to appropriately change the mixing ratio according to, for example, the driving conditions and required performance of the vehicle. On the contrary, it is possible to always maintain the mixing ratio constant.

On the other hand, when the mixing ratio is variable as described above, a mechanism for changing the injection amount in accordance with the mixing ratio is required. In that respect, according to the present invention, the heat generation amount of the liquid is specified by the first heat generation amount specifying means, or in some cases, further by the second heat generation amount specifying means, so that the mixing ratio is accompanied by any change mode. Even if it changes, it is possible to easily optimize the injection amount of the emulsion fuel. That is, this type of generating means can operate effectively only when the control device for an internal combustion engine according to the present invention exists.

Such an operation and other advantages of the present invention will be clarified from the best mode for carrying out the invention described below.

1 is a schematic configuration diagram conceptually showing a configuration of an engine system according to a first embodiment of the present invention. It is a schematic block diagram which represents notionally the structure of the fuel supply apparatus in the engine system of FIG. 2 is a flowchart of injection control executed by an ECU in the engine system of FIG. It is a schematic block diagram which represents notionally the structure of the fuel supply apparatus which concerns on 2nd Embodiment of this invention. It is a schematic block diagram which represents notionally the structure of the fuel supply apparatus which concerns on 3rd Embodiment of this invention. It is a schematic block diagram which represents notionally the structure of the fuel supply apparatus which concerns on 4th Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Engine system, 100 ... ECU, 200 ... Engine, 203 ... Intake pipe, 204 ... Throttle valve, 208 ... Unit injector, 213 ... Exhaust pipe, 300 ... Fuel supply device, 301 ... Main tank, 302 ... Low pressure feed pipe, 303 ... Filter, 304 ... Low pressure electric pump, 305 ... First sub tank, 306 ... Low pressure feed pipe, 307 ... Filter, 308 ... Low pressure electric pump, 309 ... Mixer, 310 ... High pressure feed pipe, 311 ... High pressure electric pump, 312 ... Relief pipe, 313 ... return pipe, 400 ... fuel supply device, 500 ... fuel supply device, 600 ... fuel supply device.

<Embodiment of the Invention>
<First Embodiment>
<Configuration of Embodiment>
First, the configuration of the engine system 10 according to the first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a schematic configuration diagram conceptually showing the configuration of the engine system 10.

1, an engine system 10 is mounted on a vehicle (not shown) and includes an ECU 100, an engine 200, and a fuel supply device 300 described later.

The ECU 100 is an electronic control unit that includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like, and is configured to control operations of the engine 200 and the fuel supply device 300. It is an example of a “control device for an internal combustion engine” according to the present invention. The ECU 100 is configured to be able to execute injection control described later according to a control program stored in the ROM.

Note that the ECU 100 is one of the “first heat generation amount specifying means”, “determination means”, “injection control means”, “moisture content specifying means”, “reaction efficiency specifying means”, and “generation control means” according to the present invention. It is an integrated electronic control unit that functions as an example, and all the operations related to these means are configured to be executed by the ECU 100. However, the physical, mechanical, and electrical configurations of each of the units according to the present invention are not limited to this. For example, each of these units includes a plurality of ECUs, various processing units, various controllers, a microcomputer device, and the like. It may be configured as various computer systems.

Engine 200 is an in-line four-cylinder diesel engine that is an example of an “internal combustion engine” according to the present invention that uses emulsion fuel described later as fuel. The outline of the engine 200 will be described. The engine 200 has a configuration in which four cylinders 202 are arranged in parallel in a cylinder block 201. The force generated when the air-fuel mixture containing the fuel is compressed and ignited in each cylinder causes a piston (not shown) to reciprocate in a direction perpendicular to the paper surface, and is further connected to the piston via a connecting rod. It is configured to be converted into a rotational motion (both not shown). Below, the principal part structure of the engine 200 is demonstrated with a part of the operation | movement. The engine 200 according to this embodiment is an in-line four-cylinder diesel engine in which four cylinders 202 are arranged in parallel in a direction perpendicular to the paper surface in FIG. 1, but the configuration of the individual cylinders 202 is equal to each other. Here, only one cylinder 202 will be described.

In the combustion of the air-fuel mixture in the cylinder 202, the intake air, which is the air sucked from the outside through the air filter, is guided to the intake pipe 203. A diesel throttle valve 204 capable of adjusting the amount of intake air is disposed in the intake pipe 203. The diesel throttle valve 204 is a rotary valve that is configured to be rotatable by a driving force supplied from a throttle valve motor (not shown) that is electrically connected to the ECU 100 and controlled by the ECU 100 in a higher level. The rotational position is continuously controlled from the fully closed position where the upstream portion and the downstream portion of the intake pipe 203 at the boundary of 204 are substantially blocked to the fully opened position where the intake pipe 203 communicates almost entirely.

The engine 200 is a diesel engine, and its output is controlled through increase / decrease control of the injection amount, unlike air-fuel ratio control (control according to the intake air amount) performed in an engine using gasoline or the like as fuel. The Therefore, the diesel throttle valve 204 is basically controlled to the fully open position (the position of the illustrated diesel throttle valve 204 corresponds to the fully open position) during the operation period of the engine 200. A first intake air temperature sensor 205 capable of detecting the intake air temperature, which is the temperature of the intake air that has passed through the diesel throttle valve 204, is disposed on the downstream side (cylinder side) of the diesel throttle valve 204. The first intake air temperature sensor 205 is electrically connected to the ECU 100, and the detected intake air temperature is referred to by the ECU 100 at a constant or indefinite period.

The intake pipe 203 communicates with the intake manifold 206 on the downstream side of the first intake air temperature sensor 205 (the direction concept based on the intake flow direction, in this case, the cylinder side). Further, it communicates with an intake port 207 provided in each cylinder. On the other hand, the intake air guided to the intake pipe 203 is mixed with EGR gas, which will be described later, at the merging position downstream of the first intake temperature sensor 205 and upstream of the intake manifold 206, and communicates the intake port 207 and the inside of the cylinder. When the intake valve (not shown) configured to be able to be opened is opened, it is sucked into the cylinder 202 as intake air.

In the cylinder 202, a fuel injection nozzle of a direct injection type unit injector 208 is exposed, and fuel is injected from this nozzle. The injected fuel is mixed with the intake air inside each cylinder and becomes the above-described air-fuel mixture. In addition, the fuel corresponding to the target injection amount in each cylinder 202 passes through the unit injector 208 to prevent a rapid temperature rise in the combustion chamber or to sufficiently premix the fuel and the intake air. Therefore, the fuel injection is divided into main injection corresponding to the difference between the target injection amount and the pilot injection amount.

Here, to supplement the configuration of the unit injector 208, the unit injector 208 includes a solenoid valve that operates based on a command supplied from the ECU 100, and a nozzle that injects fuel when the solenoid valve is energized (both not shown). With. The solenoid valve is configured to be able to control the communication state between the pressure chamber to which the high-pressure fuel of the common rail 209 is applied and the low-pressure side low-pressure passage connected to the pressure chamber. The chamber and the low pressure passage are communicated with each other, and the pressurizing chamber and the low pressure passage are shut off from each other when energization is stopped.

On the other hand, this nozzle has a built-in needle that opens and closes the nozzle hole, and the fuel pressure in the pressure chamber urges the needle in the valve closing direction (direction in which the nozzle hole is closed). Accordingly, when the pressure chamber and the low-pressure passage are connected by energization of the solenoid valve and the fuel pressure in the pressure chamber decreases, the needle rises in the nozzle and opens (opens the nozzle hole), thereby causing the common rail 209 to open. The high-pressure fuel supplied more can be injected from the injection hole. In addition, when the energization of the solenoid valve is stopped, the pressurization chamber and the low pressure passage are cut off from each other and the fuel pressure in the pressure chamber rises, and the needle is lowered in the nozzle to close the valve, thereby terminating the injection. It has become.

The common rail 209 is high-pressure storage means that is electrically connected to the ECU 100 and configured to accumulate fuel supplied from the fuel supply device 300 up to a target rail pressure. The common rail 209 is provided with a rail pressure sensor capable of detecting the rail pressure and a pressure limiter for limiting the amount of fuel accumulated so that the rail pressure does not exceed the upper limit value. The illustration is omitted. The unit injector 208 described above is mounted for each cylinder 202, and each unit injector 208 is connected to the common rail 209 via the high-pressure delivery 210. For the purpose of preventing complication of the drawing, the fuel supply device 300 will be described in detail later with reference to FIG.

The above-described air-fuel mixture burns by self-ignition in the compression process, and opens an exhaust valve (not shown) that opens and closes in conjunction with opening and closing of the intake valve as a burned gas or a partially unburned air-fuel mixture The structure is sometimes led to the exhaust manifold 212 via the exhaust port 211. The exhaust manifold 212 communicates with the exhaust pipe 213, and most of the exhaust gas is guided to the exhaust pipe 213.

On the other hand, a turbine 215 is installed in the exhaust pipe 213 so as to be accommodated in the turbine housing 214. The turbine 215 is configured to be rotatable about a predetermined rotation axis by the pressure of exhaust gas (that is, exhaust pressure) guided to the exhaust pipe 213. The rotating shaft of the turbine 215 is shared with the compressor 216 installed in the intake pipe 203 so as to be accommodated in the compressor housing 217. When the turbine 215 is rotated by exhaust pressure, the compressor 216 is also centered on the rotating shaft. It is configured to rotate.

The compressor 216 is configured to be able to pump and supply the intake air guided to the intake pipe 203 to the intake manifold 206 described above by the pressure accompanying the rotation thereof. Supercharging is realized. In other words, the turbine 215 and the compressor 216 constitute a kind of turbocharger. An intercooler may be installed between the compressor 216 and the intake manifold 206, and the supercharging efficiency may be improved by cooling the supercharged intake air.

Note that an air flow meter 218 and a second intake air temperature sensor 219 are disposed on the upstream side of the compressor 216 in the intake pipe 203. The air flow meter 218 is a device that detects the amount of intake air (intake air amount) guided to the intake pipe 203 and adopts a so-called hot wire type. The second intake air temperature sensor 219 is a temperature sensor configured to be able to detect the temperature of intake air near the air flow meter 218. The second intake air temperature sensor 219 is electrically connected to the ECU 100, and the detected intake air temperature is used to improve the detection accuracy of the intake air amount by the air flow meter 218.

The EGR passage 220 communicates with the exhaust manifold 212 separately from the exhaust pipe 213. The EGR passage 220 is a metal and hollow tubular member that allows the exhaust manifold 212 and the intake pipe 203 to communicate with each other, and is configured to communicate with the intake pipe 203 at the above-described joining position. The EGR passage 220 branches into a cooling passage 221 in which the EGR cooler 222 is installed and a bypass passage 223 in which the EGR cooler 222 is not installed in a part of the EGR passage 220.

The EGR cooler 222 is a cooling device provided in the EGR passage 220. The EGR cooler 222 is a metal and hollow tubular member with the cooling water piping of the engine 200 stretched around the outer periphery, and is exhausted through the EGR cooler 222 through the cooling passage 221 through the cooling passage 221. , Which is an example of “EGR gas” according to the present invention, and hereinafter referred to as “EGR gas”) is cooled by heat exchange with the cooling water and guided to the downstream side (that is, the intake pipe 203 side). It has become. The EGR cooler 222 is connected to an inlet pipe and an outlet pipe that communicate with the water jacket described above. At this time, the cooling water flows into the cooling water pipe from the inlet pipe and is discharged out of the cooling water pipe through the outlet pipe. The discharged cooling water is returned to the cooling water circulation system of the engine 200, and is supplied again from the inlet pipe through a predetermined path. The bypass passage 223 described above is configured to bypass at least the EGR cooler 222.

The switching valve 224 is a valve mechanism including an openable / closable valve body installed at a branch portion between the EGR passage 220 and the bypass passage 223 and a driving device for driving the valve body. The valve body of the switching valve 224 is configured such that the open / close state is continuously changed by the driving device, and the flow rate ratio of EGR gas between the cooling passage 221 and the bypass passage 223 according to the open / close state. It is possible to control. The driving device of the switching valve 224 is electrically connected to the ECU 100, and the opening / closing state of the valve body of the switching valve 224 is controlled to the upper level by the ECU 100.

The EGR valve 225 includes a valve body that is installed in the EGR passage 220 on the downstream side (intake pipe 203 side) where the cooling passage 221 and the bypass passage 223 are joined, and a driving device that drives the valve body. Mechanism. The valve body of the EGR valve 225 is configured such that the open / close state is continuously changed by the driving device, and the flow rate of the EGR gas flowing through the EGR passage 220, that is, the EGR amount is controlled according to the open / close state. It is configured to be able to. The drive device of the EGR valve 225 is electrically connected to the ECU 100, and the opening / closing state of the valve body of the EGR valve 225 is configured to be controlled higher by the ECU 100. The EGR passage 220, the cooling passage 221, the EGR cooler 222, the bypass passage 223, the switching valve 224 and the EGR valve 225 constitute an EGR device as a whole.

A first oxidation catalyst 226, a DPF 227, and a second oxidation catalyst 228 are installed downstream of the turbine 215 in the exhaust pipe 213.

The first oxidation catalyst 226 is a catalytic converter configured to be able to oxidize CO, HC (mainly SOF), NO and the like in exhaust gas.

The DPF 227 is a filter configured to be able to capture PM in the exhaust. The DPF has a structure in which a filter made of a ceramic carrier such as cordierite or SiC is accommodated in a metal casing. This filter has a plurality of exhaust passages extending in the direction of exhaust flow and having a cross section perpendicular to the direction of exhaust flow forming a honeycomb shape. The exhaust passages are alternately sealed so that one of the exhaust inlet side and the outlet side is not adjacent to each other, and the DPF 227 has a so-called ceramic wall flow type filter structure.

The second oxidation catalyst 228 is provided on the downstream side of the DPF 227, and is configured to oxidize each main component in the exhaust gas that passes through the ceramic carrier of the DPF 227.

Although not shown, the engine system 10 includes an NE sensor configured to be able to detect the engine rotational speed NE of the engine 200 and an accelerator position configured to be able to detect an accelerator opening Ta that is an opening of an accelerator pedal. Various sensors including sensors are mounted, and each sensor is electrically connected to the ECU 100. The detection result is referred to by the ECU 100 at a constant or indefinite period, and is used for various operation controls.

Next, the configuration of the fuel supply apparatus 300 will be described with reference to FIG. FIG. 2 is a schematic configuration diagram conceptually showing the configuration of the fuel supply device 300. In the figure, the same reference numerals are given to the same portions as those in FIG. 1, and the description thereof will be omitted as appropriate.

2, the fuel supply device 300 is an example of the “generating means” according to the present invention configured to generate emulsion fuel and be supplied to the common rail 209 as the fuel described above. The fuel supply apparatus 300 includes a main tank 301, a low pressure feed pipe 302, a filter 303, a low pressure electric pump 304, a first sub tank 305, a low pressure feed pipe 306, a filter 307, a low pressure electric pump 308, a mixer 309, a high pressure feed pipe 310, and a high pressure. An electric pump 311, a relief pipe 312, a return pipe 313, a flow sensor 314 and a flow sensor 315 are provided.

The main tank 301 is a metal container configured to store the light oil FL. The light oil FL stored in the main tank 301 is an example of the “main fuel” according to the present invention.

The low-pressure feed pipe 302 is a metal tubular member having one end fixed to the bottom of the main tank 301 and the other end connected to the mixer 309. The filter 303 is a filtration device that is installed in the low-pressure feed pipe 302 and has a mesh-like filtration member configured to be able to filter the light oil FL guided to the low-pressure feed pipe 302.

The low-pressure electric pump 304 is a fluid discharge device installed between the mixer 309 and the filter 303. The low-pressure electric pump 304 is configured to suck up the light oil FL stored from the main tank 301 and supply the light oil FL to the mixer 309 at a discharge speed (that is, a discharge amount per unit time) according to the discharge pressure ( Note that the supply direction is indicated by a solid arrow in the figure), which is a so-called electric drive type centrifugal pump using a motor (not shown) as a driving force source. A driving device (not shown) that drives and controls the motor is electrically connected to the ECU 100, and the rotational speed of the motor is controlled by the ECU 100. Since the rotational speed of the motor of the low-pressure electric pump 304 is uniquely related to the discharge pressure of the light oil FL in the low-pressure electric pump 304, the supply amount of the light oil FL to the mixer 309 in the fuel supply device 300 is eventually obtained. Is configured to be controlled by the ECU 100.

The first sub tank 305 is a metal container configured to be able to store water WT. The water WT stored in the first sub tank 305 is an example of “liquid” and “water” according to the present invention.

The low-pressure feed pipe 306 is a metal tubular member having one end fixed to the bottom of the first sub tank 305 and the other end connected to the mixer 309. The filter 307 is a filtration device that is installed in the low-pressure feed pipe 306 and has a mesh-like filtration member configured to filter the water WT guided to the low-pressure feed pipe 306.

The low-pressure electric pump 308 is a fluid discharge device installed between the mixer 309 and the filter 307. The low-pressure electric pump 308 is configured to suck up the water WT stored from the first sub tank 305 and supply the water WT to the mixer 309 at a discharge speed (that is, discharge amount per unit time) according to the discharge pressure. (The supply direction is indicated by a solid arrow in the figure), which is a so-called electrically driven spiral pump using a motor (not shown) as a driving force source. A driving device (not shown) that drives and controls the motor is electrically connected to the ECU 100, and the rotational speed of the motor is controlled by the ECU 100. Since the rotational speed of the motor of the low-pressure electric pump 308 has a unique relationship with the discharge pressure of the water WT in the low-pressure electric pump 308, the supply amount of the water WT to the mixer 309 in the fuel supply device 300 is eventually obtained. Is configured to be controlled by the ECU 100.

The mixer 309 is configured to be capable of temporarily storing the light oil FL guided through the low-pressure feed pipe 302 and the water WT guided through the low-pressure feed pipe 306, and to be rotatable to the container unit. It is a mixing apparatus having an agitating member installed and an agitator configured to agitate light oil FL and water WT by rotating the agitating member. The mixer 309 is configured so that the water WT and the light oil FL can be mixed substantially uniformly by the stirring action of the stirrer. That is, in the fuel supply device 300, the emulsion fuel is finally generated by the stirring action of the mixer 309. The mixer 309 is provided with a backflow prevention mechanism that prevents backflow of emulsion fuel from the mixer 309 to the main tank 301 and the first sub tank 305.

On the other hand, one end of a high-pressure feed pipe 310 is connected to the mixer 309. The high-pressure feed pipe 310 is a metal tubular member, and the other end is connected to the common rail 209 described above. The inside of the common rail 209 has a high pressure as described above, and the high pressure feed pipe 310 has higher physical strength than the low

pressure feed pipes

302 and 306.

The high-pressure electric pump 311 is a fluid discharge device installed in a section between the mixer 309 and the common rail 209 in the high-pressure feed pipe 310. The high-pressure electric pump 311 is configured to suck up the generated emulsion fuel from the mixer 309 and supply the emulsion fuel to the common rail 209 at a discharge speed (that is, a discharge amount per unit time) according to the discharge pressure ( Note that the supply direction is indicated by a solid arrow in the figure), which is a so-called electric drive type centrifugal pump using a motor (not shown) as a driving force source. A drive device (not shown) that drives and controls the motor is electrically connected to the ECU 100, and the rotational speed of the motor is controlled by the ECU 100. Since the rotational speed of the motor of the high-pressure electric pump 311 has a unique relationship with the discharge pressure of the emulsion fuel in the high-pressure electric pump 308, the supply of emulsion fuel to the common rail 209 in the fuel supply device 300 is eventually achieved. The amount is controlled by the ECU 100. Note that the maximum discharge pressure of the high-pressure electric pump 308 is higher than that of the low-pressure

electric pumps

304 and 308 so that the emulsion fuel can be sufficiently supplied to the high-pressure common rail 209.

The relief pipe 312 is a metal tubular member having one end connected to the common rail 209 and the other end connected to the return pipe 313. Here, as described above, the common rail 209 is provided with a pressure limiter so that the rail pressure that is the internal pressure of the common rail 209 does not exceed the upper limit value. This pressure limiter is a kind of so-called pressure regulating valve, and has a configuration that opens when the rail pressure exceeds an upper limit value. The relief pipe 312 is connected to the common rail 209 via this pressure limiter, and excess emulsion fuel is supplied to the return pipe 313 when the pressure limiter is opened (the supply direction is the same). , See the broken arrows in the figure).

The return pipe 313 is connected to each unit injector 210 and the relief pipe 312 at the end on the introduction side, and excess emulsion fuel flows from these. On the other hand, the end on the discharge side of the return pipe 313 is connected to the mixer 209, and this excess emulsion fuel is finally returned to the mixer 209 (note that the supply direction is indicated by the broken line in the figure). (See arrow of). The relief pipe 312 and the return pipe 313 are respectively provided with a backflow prevention valve so that the backflow of the emulsion fuel to the common rail 209 and the unit injector 210 is prevented.

The flow rate sensor 314 is a sensor configured to be able to detect the flow rate of the light oil FL in the low pressure feed pipe 302 in which the detection terminal is exposed inside the low pressure feed pipe 302. The flow rate sensor 314 is electrically connected to the ECU 100, and the detected flow rate of the light oil FL is referred to by the ECU 100 at a constant or indefinite period.

The flow rate sensor 315 is a sensor configured to be able to detect the flow rate of the water WT in the low pressure feed pipe 306 in which the detection terminal is exposed inside the low pressure feed pipe 306. The flow rate sensor 315 is electrically connected to the ECU 100, and the detected flow rate of the water WT is referred to by the ECU 100 at a constant or indefinite period.

Here, in the fuel supply apparatus 300, the ECU 100 has a water content ratio x in the emulsion fuel generated by the mixer 309 (that is, a volume ratio of water in the fuel, which is an example of the “water content ratio” according to the present invention). The motor rotation speed of each low-pressure electric pump is controlled based on the flow rates of the light oil FL and the water WT detected by the

flow rate sensors

314 and 315 so as to obtain a desired value. For example, if the flow rate of each fuel (volume flow rate per unit time, that is, flow rate) is the same, water WT and light oil FL are present in the mixer 309 at a volume ratio of 1: 1. Therefore, the water content x is estimated to be 0.5. In other words, if the target value of the water content ratio x is 0.5, the rotational speed of each low-voltage electric motor is finally controlled so that the flow rates of the water WT and the light oil FL are equal.

In this embodiment, the water content ratio x is estimated based on the flow rate of each fuel detected by the flow sensor in this way (that is, an example of the operation of the “water content ratio specifying means” according to the present invention). . However, this kind of flow sensor or flow meter is not necessarily required for estimating the water content ratio x. For example, when the relationship between the motor rotational speed or discharge pressure of each low-pressure electric pump and the flow rate of fuel in each low-pressure feed pipe is obtained in advance by mapping, the map is referred to. The moisture content x may be estimated. Alternatively, even if a metering mechanism such as a metering valve is installed in each low pressure feed pipe, and the water content ratio x is estimated based on the control state of each metering valve (for example, valve opening, valve opening time, etc.) Good. Alternatively, a fuel property sensor or the like that can directly detect the water content ratio x in the fuel may be attached to the mixer 309.

<Operation of Embodiment>
<Outline of injection control>
As described above, the fuel supply apparatus 300 includes the mixer 309 so that the light oil FL stored in the main tank 301 and the water WT stored in the first sub-tank 305 have the target water content ratio x of the fuel that is the emulsion fuel. Therefore, the generated emulsion fuel is supplied to the common rail 209 as the above-described fuel. Here, the combustion characteristics of this fuel will be described.

First, in the fuel injected into the high-temperature and high-pressure cylinder 201 through the unit injector 208, water boils in a high-temperature field to become water vapor, and a water gas reaction shown in the following formulas (1) to (3) occurs.

H 2 O (liquid) = H 2 O (gas) −40.8 kJ / mol (1)
C + H2O (gas) = CO + H2-131.3 kJ / mol (2)
H2 + 0.5O2 = H2O (liquid) +286 kJ / mol (3)
By these water gas reactions, it is theoretically possible to obtain an exotherm of about 4.1 MJ / kg from water in the liquid state in the fuel. On the other hand, the calorific value of light oil is about 43 MJ / kg, and when converted into volume per volume taking into account the difference in density between the two, the heat generated from water theoretically corresponds to the calorific value of about 11% of light oil. It is possible to obtain. Accordingly, the fuel injection amount in the unit injector 208 deviates from an appropriate value unless the heat generation amount of the water is taken into consideration.

For example, it is assumed that the required calorific value is “1” in terms of light oil volume, and the water content of the fuel is 0.2. In this case, if the heat generation amount of water is ignored and treated as zero, the injection amount is about 1.25 (1.25 × 0.8 = 1) so that the volume of light oil in the fuel becomes 1. However, in the fuel having the volume of 1.25, the water occupying the volume of 0.25 can generate heat of about 11% as compared with the light oil described above. Theoretically, it becomes 1.0275 (1 + 0.25 × 0.11 = 1.0275), and about 3% of excessive heat generation occurs. On the other hand, if the calorific value of water is treated as equivalent to that of light oil (in short, the existence of water itself can be ignored), the injection amount can be 1 in volume, but it has a volume of injection amount 1 Since water that occupies a volume of 0.2 in the fuel only generates heat of about 11% of the light oil ratio described above, the calorific value of the fuel is theoretically 0.882 (0.8 + 0.2). × 0.11 = 0.822), resulting in a shortage of heat generation of about 17.8%. In any case, in the category of these technical ideas in which the calorific value of water cannot be reflected in the injection amount with accuracy that is practically acceptable, there are problems such as a decrease in power performance due to fuel shortage and emissions or deterioration in fuel consumption due to excessive fuel. It is difficult to avoid.

<Details of injection control>
In the engine system 10, in order to solve such a problem, proper fuel injection that accurately reflects the amount of heat generated in water contained in the fuel is realized by injection control executed by the ECU 100. The details of the injection control will be described below with reference to FIG. FIG. 3 is a flowchart of the injection control.

In FIG. 3, the ECU 100 acquires the driving conditions of the vehicle (step S101). In step S101, the engine speed NE and the accelerator opening degree Ta of the engine 200 are acquired. When the engine speed NE and the accelerator opening degree Ta are acquired as the vehicle operating conditions, the ECU 100 acquires the basic injection time Tau0 (step S102).

Here, the basic injection time Tau0 is a control amount that defines a basic injection amount that is a basic value of the fuel injection amount (that is, an example of the “basic injection amount” according to the present invention). In the engine 200, the fuel injection amount is proportional to the injection time TAU corresponding to the opening period of the injection hole in the unit injector 208 because the rail pressure of the common rail 209 is constant. The unit injector 208 is configured to control the operation state (for example, the control duty ratio of the solenoid valve) using the injection time TAU as a control target.

The value of the basic injection time Tau0 is stored in advance in the basic injection time map in a form associated with the engine speed NE and the accelerator opening degree Ta. ECU 100 selectively acquires one value corresponding to these values acquired in step S101 from the basic injection time map as basic injection time Tau0. The basic injection time Tau0 corresponds to the injection amount when the moisture content x of the fuel is 0, that is, when the fuel is light oil itself.

When acquiring the basic injection time Tau0, the ECU 100 acquires the water content ratio x (step S103). Since the water content ratio x is estimated by the ECU 100 itself based on the flow rates of the water WT and the light oil FL detected by the

flow sensors

314 and 315 as described above, in step S103, the ECU 100 x can be easily obtained.

When the moisture content x is acquired, the reaction efficiency k of water in the fuel is acquired (step S104). Here, the reaction efficiency k is, for example, a correction coefficient that reflects the probability of occurrence of a reaction corresponding to the above formula (2) or (3), the probability that various reactions different from the above formula (2) or (3) occur, and the like. The case where the occurrence of the reaction corresponding to the above equations (2) and (3) occurs 100% with respect to water or hydrogen contained in the fuel is standardized as “1”. Since the reaction efficiency k is influenced by the fuel spatial distribution in the combustion chamber, the temperature distribution of the combustion chamber, and the like, it is set in advance for each engine 200 (that is, for each actual machine) through experimental adaptation. The set reaction efficiency k is stored in the ROM of the ECU 100 as a fixed value or as a reaction efficiency map using the vehicle operating conditions as parameters. In step S104, the ECU 100 acquires this kind of preset reaction efficiency k from the ROM.

When the water content ratio x and the reaction efficiency k are acquired, the ECU 100 uses the basic injection time Tau0 acquired in step S102 as the calorific value of water in the fuel calculated using the water content ratio x and the reaction efficiency k. And the injection time Tau1 that is the final fuel injection time is calculated (step S105). Here, in step S105, the ECU 100 calculates the injection time Tau1 according to the following equation (4). In the expression, “·” is a multiplication operator.

_{Tau1 = Tau0 · 1 / (x} · (Q f / (Q w · k)) · (δ f / δ w) + (1-x)) ... (4)
Here, Q _f is the calorific value per unit weight of the main fuel (light oil in the present embodiment) (in the case of light oil, as described above, about 43 MJ / kg), and Q _w is the unit weight of water. Δ _f is the density of the main fuel (0.8336 g / cc in the case of light oil), and δ _w is the density of water (as described above, approximately 4.1 MJ / kg). 1 g / cc).

When the injection time Tau1 is calculated, the ECU 100 drives the unit injector 208 according to the calculated injection time Tau1 and executes fuel injection (step S106). When fuel injection is executed, the process returns to step S101. The injection control is executed as described above.

As described above, according to the present embodiment, the calorific value of water continuously changing according to the water content ratio x in the fuel generated as the emulsion fuel is accurately calculated, and the basic value reflecting the calorific value of the water is calculated. Accurate correction of the injection amount Tau0 becomes possible. In this embodiment, in particular, the concept of the reaction efficiency k of water in the fuel is further introduced, and based on this reaction efficiency k, the calorific value of water obtained in the water gas reaction as an actual phenomenon that may differ from the theoretical value ( That is, it is possible to calculate a more realistic water heat generation amount). For this reason, it is possible to specify the water content ratio x whether the water content ratio x of the fuel is a fixed value, can be changed under a preset condition, or changes abruptly. Insofar as any technical idea that does not reflect the influence of heat generated by the oxidation reaction of hydrogen during the water gas reaction of water on the power generation in the engine 200, the final fuel injection amount (ie, The injection amount corresponding to the injection time Tau1) can be made as close as possible to the truly required injection amount. That is, it is possible to optimize the fuel injection amount, and it is possible to suitably suppress the deterioration of power performance and the deterioration of fuel consumption and emission due to the excess or shortage of the fuel injection amount.

Second Embodiment
Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 4 is a schematic configuration diagram conceptually showing the configuration of the fuel supply apparatus 400 according to the second embodiment of the present invention. 4 that are the same as those in FIG. 2 are given the same reference numerals, and descriptions thereof are omitted as appropriate.

In FIG. 4, in the fuel supply apparatus 400, water ethanol WTALC that is a mixture of water and ethanol (that is, another example of “alcohol” according to the present invention) is stored in the first sub tank 305 instead of the water WT. In this respect, the configuration is different from the fuel supply device 300 in the first embodiment. Water ethanol WTALC is another example of the “liquid” according to the present invention. That is, the fuel in this embodiment is an emulsion fuel in which water, ethanol, and light oil are mixed. In the present embodiment, the volume ratio of water and ethanol in the water ethanol WTALC is fixed.

In the present embodiment, the flow rate sensor 315 detects the flow rate of the water ethanol WTALC in the low pressure feed pipe 306. As described above, in this embodiment, since the volume ratio of water to ethanol in the water ethanol WTALC is fixed, the ECU 100 detects the detected flow rate of the water ethanol WTALC and the flow rate sensor 314. Based on the flow rate of the light oil FL, it is possible to calculate the water content ratio x and the ethanol content ratio y (the volume ratio is the same as the water content ratio x).

In such a configuration, it is necessary to consider the heating value of ethanol as well as the heating value of water. Therefore, in the injection control according to the second embodiment (note that the flowchart is omitted), the ECU 100 corrects the basic injection time Tau0 according to the following equation (5), and sets the injection time Tau2 in consideration of the heat generation amounts of water and ethanol. calculate. In the formula (5), Q _e is the maximum calorific value per unit weight of the lower alcohol (ethanol in this embodiment) (about 27 MJ / kg in the case of ethanol), and δ _e is the lower alcohol The density is 0.789 g / cc in the case of ethanol.

Tau2 = Tau0 · 1 / (x · (Q _f / (Q _w · k)) · (δ _f / δ _w ) + y · (Q _f / Q _e ) · (δ _f / δ _e ) + (1-x -Y)) ... (5)
According to the above formula (5), it is possible to accurately grasp the calorific value per unit volume even in the case of an emulsion fuel containing water and ethanol in addition to the light oil as the main fuel. In addition, it is possible to suitably suppress deterioration of fuel consumption and emission. In particular, when there are many fuel elements constituting the emulsion fuel in this way, it is practically impossible to obtain an optimal fuel injection amount corresponding to the water content ratio x and ethanol content ratio k in advance by conformance or the like and store it in a map or the like. Nearly possible and an increase in the cost of adaptation can certainly be realized. In that respect, a configuration having a technique capable of deriving the injection amount by numerical calculation processing as in the present embodiment is clearly advantageous.

<Third Embodiment>
Next, a third embodiment of the present invention will be described with reference to FIG. FIG. 5 is a schematic configuration diagram conceptually showing the configuration of the fuel supply apparatus 500 according to the third embodiment of the present invention. 5 that are the same as those in FIG. 2 are denoted by the same reference numerals, and the description thereof is omitted as appropriate.

In FIG. 5, the fuel supply device 500 includes a second sub tank 501, a low pressure feed pipe 502, a filter 503, a low pressure electric pump 504, a mixer 505, a flow sensor 506, and a flow sensor 507, according to the first embodiment. This is different from the supply device 300.

The second sub tank 501 is a metal container configured to store ethanol ALC. The ethanol ALC stored in the second sub tank 501 is an example of “liquid” and “alcohol” according to the present invention.

The low-pressure feed pipe 502 is a metal tubular member having one end fixed to the bottom of the second sub tank 501 and the other end connected to the mixer 505. The filter 503 is a filtration device that is installed in the low-pressure feed pipe 502 and has a mesh-like filtration member configured to be able to filter ethanol ALC guided to the low-pressure feed pipe 502.

The low-pressure electric pump 504 is a fluid discharge device installed between the mixer 505 and the filter 503. The low-pressure electric pump 504 is configured to suck up the ethanol ALC stored from the second sub tank 501 and supply the ethanol ALC to the mixer 505 at a discharge speed (that is, a discharge amount per unit time) according to the discharge pressure. This is a so-called electrically driven centrifugal pump using a motor (not shown) as a driving force source. A driving device (not shown) that drives and controls the motor is electrically connected to the ECU 100, and the rotational speed of the motor is controlled by the ECU 100. Since the rotational speed of the motor of the low-pressure electric pump 504 is uniquely related to the discharge pressure of the ethanol ALC in the low-pressure electric pump 504, the amount of ethanol ALC supplied to the mixer 505 in the fuel supply device 500 is eventually obtained. Is configured to be controlled by the ECU 100.

The mixer 505 is configured to be capable of temporarily storing water WT guided through the low-pressure feed pipe 306 and ethanol ALC guided through the low-pressure feed pipe 502, and rotatable to the container unit. It is a mixing apparatus having an agitating member installed and an agitator configured to agitate water WT and ethanol ALC by rotating the agitating member. The mixer 505 is configured so that water WT and ethanol ALC can be mixed substantially uniformly by the stirring action of the stirrer. That is, in the fuel supply device 500, first, a homogeneous mixture of water and ethanol similar to the water ethanol WTALC in the second embodiment is generated by the stirring action of the mixer 505, and this uniform mixture of water and ethanol is further generated. Then, it is mixed with the light oil FL by the mixer 309, and finally an emulsion fuel of the light oil, water and ethanol is generated.

The flow rate sensor 506 is a sensor configured to be able to detect the flow rate of ethanol ALC in the low-pressure feed pipe 502 in which the detection terminal is exposed inside the low-pressure feed pipe 502. The flow rate sensor 506 is electrically connected to the ECU 100, and the detected flow rate of the ethanol ALC is referred to by the ECU 100 at a constant or indefinite period.

The flow rate sensor 507 measures the flow rate of the homogeneous mixture of water WT and ethanol ALC in the low-pressure feed pipe 306, with the detection terminal exposed inside the low-pressure feed pipe 306 on the downstream side (mixer 309 side) of the mixer 505. This is a sensor configured to be detectable. The flow rate sensor 507 is electrically connected to the ECU 100, and the detected flow rate of the mixture is referred to by the ECU 100 at a constant or indefinite period.

According to such a configuration of the fuel supply device 500, the volume ratio of the water WT and the ethanol ALC in the mixer 505 can be estimated based on the flow rates of the water WT and the ethanol ALC detected by the

flow sensors

315 and 506. It becomes possible. Therefore, as in the second embodiment, even if the volume ratio of water WT and ethanol ALC is not fixed, in the emulsion fuel having the light oil FL, water WT, and ethanol ALC generated in the mixer 309 as constituent elements. It is possible to accurately estimate the water content ratio x and the ethanol content ratio y.

For example, let x: y be the volume ratio of water WT and ethanol ALC. On the other hand, the volume ratio of the light oil FL to the homogeneous mixture of water WT and ethanol ALC is defined as v: w. From these relationships, the volume ratio among the light oil FL, water WT, and ethanol ALC is 1: ((x / (x + y)) · w / v): ((y / (x + y)) · w / v) = (X + y) · v: x · w: y · w

Here, if the first, second and third terms on the right side are Z, X and Y, respectively, and x ′ = X / (X + Y + Z) and y ′ = Y / (X + Y + Z), the light oil FL and water The ratio of WT to ethanol ALC is (1−x′−y ′): x ′: y ′. In the present embodiment, using these x 'and y', the injection time TAU0 is corrected according to the following equation (6) to calculate the injection time TAU3.

Tau3 = Tau0 · 1 / (x '· (Q f / (Q w · k)) · (δ f / δ w) + y' · (Q f / Q e) · (δ f / δ e) + (1 −x′−y ′)) (6)
Thus, according to this embodiment, even if the ratio of the light oil FL, the water WT, and the ethanol ALC changes intentionally, accidentally, or transiently, the fuel injection amount is maintained at the optimum value. Is possible. Therefore, similarly to the second embodiment, it is possible to suitably suppress the deterioration of power performance, fuel consumption, and emission.

<Fourth embodiment>
Next, a fourth embodiment of the present invention will be described with reference to FIG. FIG. 6 is a schematic configuration diagram conceptually showing the configuration of the fuel supply apparatus 600 according to the fourth embodiment of the present invention. In FIG. 6, the same reference numerals are given to the same portions as those in FIG.

6, the fuel supply device 600 is different from the fuel supply device 500 according to the third embodiment in that it includes

temperature sensors

601 and 602.

The temperature sensor 601 is a sensor configured to detect the temperature Tf of the light oil FL, the detection terminal of which is exposed inside the main tank 301. The temperature sensor 601 is electrically connected to the ECU 100, and the detected temperature Tf of the light oil FL is referred to by the ECU 100 at a constant or indefinite period.

The temperature sensor 602 is a sensor configured to detect the temperature Te of ethanol ALC, the detection terminal of which is exposed inside the second sub tank 501. The temperature sensor 602 is electrically connected to the ECU 100, and the detected temperature Te of the ethanol ALC is referred to by the ECU 100 at a constant or indefinite period.

Thus, according to the fuel supply apparatus 600 configured to be able to detect the temperature Tf of the light oil FL and the temperature Te of the ethanol ALC, the basic injection amount is further increased in consideration of the density change due to the temperature in each of the light oil FL and the ethanol ALC. It becomes possible to correct TAU0 accurately. In the injection control according to the present embodiment, the ECU 100 calculates the injection amount TAU4 according to the following equation (7).

Tau4 = Tau0 · 1 / (x '· (Q f / (Q w · k)) · (δ f' / δ w) + y '· (Q f / Q e) · (δ f' / δ e ') + (1−x′−y ′)) (7)
In the above equation (7), δf ′ is the density of the main fuel (light oil in this embodiment) after temperature correction, and in the case of light oil, is defined by the following equation (8). In the above equation (7), δe ′ is the density of the lower alcohol (in this embodiment, ethanol) after temperature correction. In the case of ethanol, it is defined by the following equation (9).

δf ′ = δf · (1 + 0.85 · 0.001 · (15−Tf [° C.]) (8)
δe ′ = δe · (1 + 1.91818 · 0.001 · (15−Te [° C.]) (9)
According to this embodiment, even if the density change caused by the temperature change occurs in the light oil FL and the ethanol ALC, the calorific value due to the density change is calculated based on the above formulas (7), (8) and (9). The error can be suitably corrected. Therefore, the fuel injection amount can be optimized under a wider range of operating conditions, which is extremely useful in practice. Although the case where the volume ratio of water WT and ethanol ALC is variable is shown here, even when the volume ratio is a fixed value as in the second embodiment, Needless to say, the injection amount can be similarly calculated by applying the density after temperature correction defined by the above equations (8) and (9).

In each of the first to fourth embodiments, the engine 200 is a diesel engine and the main fuel is light oil FL. However, the fuel injection amount correction described in each of the above embodiments is not limited to the main fuel. The same applies to the case where gasoline is used as gasoline.

The present invention is not limited to the above-described embodiment, and can be appropriately changed without departing from the gist or concept of the invention that can be read from the claims and the entire specification, and the control of the internal combustion engine accompanying such a change. The apparatus is also included in the technical scope of the present invention.

Industrial applicability

INDUSTRIAL APPLICABILITY The present invention can be used for controlling the injection amount of an emulsion fuel in an internal combustion engine that can be installed in a vehicle and can use an emulsion fuel in which a main fuel and a liquid containing at least water are mixed as fuel. is there.

Claims

A control device for an internal combustion engine, mounted on a vehicle, configured to be able to use an emulsion fuel obtained by mixing a main fuel and a liquid containing at least water, and having an injection means capable of injecting the emulsion fuel. ,
First heat value specifying means for specifying the heat value of the water in the emulsion fuel;
Determining means for determining an injection amount of the emulsion fuel based on a driving condition of the vehicle and a heat generation amount of the specified water;
An internal combustion engine control apparatus comprising: an injection control unit that controls the injection unit so that the emulsion fuel corresponding to the determined injection amount is injected.
Further comprising water content specifying means for specifying the water content of the emulsion fuel,
2. The control device for an internal combustion engine according to claim 1, wherein the first heat generation amount specifying unit specifies a heat generation amount of water in the emulsion fuel based on the specified water content ratio. 3.
Further comprising reaction efficiency specifying means for specifying the reaction efficiency of the water in the emulsion fuel,
The internal combustion engine according to claim 1 or 2, wherein the first calorific value specifying means specifies the calorific value of water in the emulsion fuel based on the specified reaction efficiency. Control device.
The determination means determines the injection amount of the emulsion fuel by correcting a basic injection amount of the emulsion fuel determined according to an operating condition of the vehicle based on the heat generation amount of the specified water. The control apparatus for an internal combustion engine according to any one of claims 1 to 3, wherein:
The emulsion fuel contains alcohol as the liquid,
Further comprising second calorific value specifying means for specifying the calorific value of the alcohol in the emulsion fuel;
The internal combustion engine according to any one of claims 1 to 4, wherein the determining means determines an injection amount of the emulsion fuel based on a heat generation amount of the specified alcohol. Control device.
Further comprising alcohol content ratio specifying means for specifying the alcohol content ratio of the emulsion fuel;
The control device for an internal combustion engine according to claim 5, wherein the second calorific value specifying means specifies the calorific value of alcohol in the emulsion fuel based on the specified alcohol content ratio.
A temperature specifying means for specifying the temperature of the emulsion fuel;
The control device for an internal combustion engine according to any one of claims 1 to 6, wherein the determining means determines an injection amount of the emulsion fuel based on the specified temperature. .
The vehicle further includes generating means capable of generating the emulsion fuel by mixing the main fuel and the liquid,
The control device for the internal combustion engine includes:
8. The method according to claim 1, further comprising generation control means for controlling the generation means so that the main fuel and the liquid are mixed at a desired mixing ratio. The control apparatus for an internal combustion engine according to the item.