Alcohol-containing fuel engine system and vehicle

Abstract

The present invention provides: an alcohol-containing fuel engine system that can achieve both exhaust gas purification performance and cold startability in an engine in which alcohol-containing fuel is supplied to an intake passage but in which direct injection is not performed; and a vehicle provided with the same. This alcohol-containing fuel engine system further advances an ignition crank angle of at least one cylinder toward MBT in at least part of a cold start period after complete combustion in comparison to the ignition crank angle during normal operation and further decreases an injection amount of alcohol-containing fuel per cycle in an intake passage in comparison to an average injection amount in the intake passage per cycle until complete combustion so as to at least partially offset a torque increase due to said advance within the range in which the exhaust air-fuel ratio is not further to the lean side in comparison to stoichiometry, and short-time injection in the intake passage is completed at a crank angle delayed so as to be closer to a crank angle at which an intake valve opens in comparison to an injection completion crank angle during normal operation.

Description

Alcohol-containing fuel engine system and vehicle

[0001] The present invention relates to an engine system using an alcohol-containing fuel and a vehicle equipped with the same.

[0002] Patent Document 1 relates to an engine in which an alcohol-containing fuel is supplied to an intake path (e.g., claim 1 of Patent Document 1). Patent Document 1 mentions a problem with unburned alcohol fuel: when the catalyst has not yet reached its activation temperature, such as immediately after engine start, the unburned alcohol fuel is not sufficiently purified, resulting in the unburned alcohol fuel being discharged outside the engine (e.g., paragraph

[0005] of Patent Document 1). Patent Document 1 also mentions achieving both engine startability in cold conditions and the catalyst's exhaust gas purification performance (e.g., paragraphs

[0006] to

[0007] of Patent Document 1). To address this problem, Patent Document 1 discloses a technology for adjusting the amount of alcohol-containing fuel supplied to the intake path when the alcohol content in the exhaust gas exceeds a threshold value in an engine in which an alcohol-containing fuel is supplied to the intake path. Patent Document 1 cites a three-way catalyst as an example of the catalyst.

[0003] JP 2011-153601 A

[0004] In an engine in which alcohol-containing fuel is supplied to an intake passage but direct injection is not performed, it is desirable to achieve both exhaust gas purification performance and cold startability.

[0005] The object of the present invention is to provide an alcohol-containing fuel engine system that can achieve both exhaust gas purification performance and cold startability in an engine in which alcohol-containing fuel is supplied to the intake passage but in-cylinder injection is not performed, and a vehicle equipped with the same.

[0006] In view of the above-mentioned problems, the inventors of the present invention have conducted extensive research into how to efficiently introduce alcohol-containing fuel from the intake passage into the combustion chamber while obtaining output torque for achieving rapid cold starts in an engine in which alcohol-containing fuel is supplied to the intake passage but direct injection is not performed, and have arrived at the following findings. That is, the alcohol-containing fuel is reduced to a degree that does not cause the mixture to become lean, in a manner that offsets the increase in output torque obtained by ignition advance. This enables short-time injection into the intake passage, and the short-time injection is performed with a retarded final crank angle. This achieves efficient introduction of alcohol-containing fuel injected into the intake passage into the combustion chamber while obtaining output torque. Based on this finding, the present invention was completed. The present invention relates to technology for introducing alcohol-containing fuel from the intake passage into the combustion chamber, and is therefore essentially different from technology related to engines with direct injection.

[0007] The present invention can provide the following alcohol-containing fuel engine system.

[0008] (1) An alcohol-containing fuel engine system, comprising: an alcohol-containing fuel engine that uses alcohol-containing fuel; a control device that controls at least the alcohol-containing fuel engine; and a three-way catalyst provided in an exhaust passage of the alcohol-containing fuel engine, wherein the alcohol-containing fuel engine has at least one cylinder, and each cylinder comprises: a combustion chamber; an intake passage that takes in air into the combustion chamber; an intake passage injection device configured to inject into the intake passage the entire amount of alcohol-containing fuel supplied to the combustion chamber; and an alcohol-containing fuel ignition device that ignites the alcohol-containing fuel mixture of the alcohol-containing fuel and air taken into the combustion chamber, and is configured not to perform in-cylinder injection of the alcohol-containing fuel, and the control device controls the alcohol-containing fuel ignition device so that, for at least one cylinder, during at least a part of a cold start period after complete combustion, the ignition crank angle for igniting the alcohol-containing fuel mixture is advanced toward MBT from the ignition crank angle during normal operation, and an intake passage injection amount of the alcohol-containing fuel per cycle is reduced to be less than an average intake passage injection amount per cycle until complete combustion, within a range where the exhaust air-fuel ratio does not become leaner than stoichiometric, so as to at least partially offset the torque increase due to the advance angle, thereby enabling short-term intake passage injection of the alcohol-containing fuel, in which the intake passage injection period in one cycle is shorter than the average intake passage injection period per cycle until complete combustion, and the intake passage injection device is controlled so that the short-term intake passage injection of the alcohol-containing fuel ends at a crank angle that is retarded so as to be closer to the crank angle at which the intake valve opens, rather than the injection end crank angle during normal operation.

[0009] According to the alcohol-containing fuel engine system described above in (1), during at least a portion of the cold start period after complete combustion, the control device advances the ignition crank angle of the alcohol-containing fuel mixture toward the MBT relative to the ignition crank angle during normal operation. Advancement of the ignition crank angle increases the engine output torque. Furthermore, the control device reduces the intake manifold injection amount of the alcohol-containing fuel per cycle to at least partially offset the torque increase resulting from the advance, within a range that does not cause the exhaust air-fuel ratio to become leaner than stoichiometric. This shortens the intake manifold injection period of the alcohol-containing fuel per cycle. In other words, short-term intake manifold injection of the alcohol-containing fuel is possible. Additionally, the control device controls the intake manifold injection device to terminate the short-term intake manifold injection of the alcohol-containing fuel at a crank angle that is retarded relative to the injection end crank angle during normal operation, so that the crank angle is closer to the intake valve opening crank angle. As a result, short-time intake manifold injection of the alcohol-containing fuel can be executed so as to end at a retarded crank angle while obtaining output torque for achieving a rapid cold start. This allows the alcohol-containing fuel injected in the intake manifold to be efficiently taken into the combustion chamber from the intake manifold, and the alcohol-containing fuel can be effectively burned in the combustion chamber. Therefore, according to (1) above, in an alcohol-containing fuel engine system in which all of the alcohol-containing fuel is supplied to the combustion chamber by intake manifold injection and the exhaust gas is treated by a three-way catalyst, it is possible to generate exhaust gas with a composition suitable for purification by the three-way catalyst while obtaining output torque for achieving a rapid cold start, and it is possible to suppress the total hydrocarbon content (THC) in the exhaust gas.

[0010] An alcohol-containing fuel is a fuel composition containing alcohol as a primary component. The term "primary component" here means that the alcohol is not an impurity or an unavoidable mixture, and includes, for example, at least 1% by volume. An alcohol-containing fuel may also contain a hydrocarbon fuel. A hydrocarbon fuel may also be included as a primary component. Examples of alcohols include, but are not limited to, methanol, ethanol, propanol, and butanol. The alcohol concentration (volume concentration) may be greater than 0% by volume or substantially 100% by volume. Examples of hydrocarbon fuels include, but are not limited to, gasoline. E3, E10, E15, E20, E25, E85, and E100 may be used. E indicates the volume percentage of ethanol in a gasoline-ethanol mixture. A mixture with a different composition but equivalent concentration may also be used. The composition and alcohol concentration of the alcohol-containing fuel are not particularly limited, as long as they are applicable to an alcohol-fueled engine.

[0011] An alcohol-containing fuel engine is not particularly limited as long as the upper limit of the alcohol concentration of the applicable alcohol-containing fuel is greater than 0% by volume. Examples of such upper limits include, by volume, 3, 10, 15, 20, 25, 85, and 100. An upper limit of 20% by volume means that the alcohol-containing fuel engine can use alcohol-containing fuels with alcohol concentrations up to 20% by volume. The higher the upper limit, the higher the alcohol-containing fuel concentration that can be used. An alcohol-containing fuel engine may be configured so that the lower limit of the alcohol concentration of the applicable alcohol-containing fuel is 0% by volume. In other words, an alcohol-containing fuel engine may be able to use hydrocarbon fuels (e.g., gasoline) that do not contain alcohol. The alcohol concentration of the applicable alcohol-containing fuel is not particularly limited as long as it is within the above-mentioned upper and lower limit ranges. Furthermore, with regard to the number of cylinders, alcohol-containing fuel engines include, for example, single-cylinder engines and engines with two or more cylinders. The alcohol-containing fuel engine may be, for example, a single-cylinder engine, a two-cylinder engine, an unevenly-spaced firing three-cylinder engine, or an unevenly-spaced firing four-cylinder engine. When the alcohol-containing fuel engine has multiple cylinders, the control according to the present invention does not necessarily have to be performed on all cylinders. As long as the control according to the present invention is performed on any one cylinder, the engine system corresponds to the alcohol-containing fuel system according to the present invention.

[0012] The control device is composed of a computer having a processor, RAM, and ROM. The control device may be an ECU (Engine Control Unit). The processor performs arithmetic processing based on a control program. The processor receives data from multiple sensors provided in the system and outputs commands to control various devices in the system. The RAM functions as a memory area for temporary data storage. Examples of temporary data include data currently being processed and data from the sensors. The data from the sensors includes data related to the dynamic state of the vehicle. The ROM stores a control program and a control map. The control device controls an alcohol-fueled engine. The control device controls an inter-intake manifold injection device and an alcohol-fueled ignition device in the engine. The control device may also control devices other than the alcohol-fueled engine. The control device may be composed of a single device or multiple devices physically separated from each other. Because the control device controls an alcohol-fueled engine, different values ​​are used to adjust, for example, the fuel injection amount, ignition timing, and fuel mixture ratio compared to a gasoline engine. The present invention solves problems specific to alcohol-fueled engines.

[0013] A three-way catalyst is a catalytic converter for simultaneously converting carbon monoxide, hydrocarbons, and nitrogen oxides emitted from an alcohol-containing fuel engine. The three-way catalyst has, for example, a metal honeycomb structure. The surface of the honeycomb structure is coated with a catalytic noble metal (e.g., Pt, Pd, Rh, etc.). The three-way catalyst may be a dedicated product for alcohol-containing fuels or a general-purpose product that is also used for gasoline fuels.

[0014] The intra-intake passage injection device is a device that injects alcohol-containing fuel into the intake passage. The device is, for example, an injector. The device may be a device dedicated to alcohol-containing fuel, or a general-purpose device that is also used for gasoline fuel. The device can be selected depending on the alcohol concentration of the alcohol-containing fuel. Note that in-cylinder injection is not performed in an alcohol-containing fuel engine.

[0015] An alcohol-containing fuel ignition device is a device that ignites an alcohol-containing fuel mixture. The device is, for example, an ignition system. The device does not need to be a dedicated device for alcohol-containing fuel, but may be a general-purpose device that can also be used for gasoline fuel.

[0016] Complete combustion refers to a state in which the crankshaft is driven independently by the combustion of the alcohol-containing fuel mixture without the need for an external driving force such as a motor. The number of ignitions required to achieve complete combustion is not particularly limited, and complete combustion may be achieved by the first ignition or by the second or subsequent ignitions. The average intake passage injection amount per cycle until complete combustion is, for example, defined as I=1 / i=1. （ｉ） If complete combustion occurs at the Nth ignition, the average injection amount in the passage is (1 / N)Σ(i=1 to N)I （ｉ） (where i is an integer from 1 to N).

[0017] The cold start period refers to the period from complete combustion until a condition for terminating the cold start period is satisfied. The termination condition is not particularly limited, and examples include the passage of a predetermined period after the start of the engine or complete combustion, or the satisfaction of a predetermined condition in data obtained from a sensor installed in the alcohol-containing fuel engine system or vehicle. Examples of the data satisfying the predetermined condition include the engine speed reaching a predetermined value or the inlet temperature of the three-way catalyst reaching a predetermined temperature. As described below, the cold start period may be at least a portion of the period until the inlet temperature of the three-way catalyst reaches 400°C. When the inlet temperature of the three-way catalyst is 400°C, the three-way catalyst is activated. As described below, the cold start period may be at least a portion of the high idle period during cold start. Here, "at least a portion" may refer to a continuous period following complete combustion. Therefore, examples of "at least a portion of the cold start period after complete combustion" include the period from complete combustion until the inlet temperature of the three-way catalyst reaches 350°C or the period from complete combustion until the end of high idle. The engine speed during high idle is higher than the engine speed during normal operation.

[0018] MBT (Minimum advance for Best Torque) is the ignition advance angle of an alcohol-containing fuel engine at which the torque of the alcohol-containing fuel engine is at its maximum.

[0019] The injection amount per cycle in short-time intake manifold injection is less than the average intake manifold injection amount per cycle until complete combustion, and may be less than half of the first injection amount, less than half of the second injection amount in the case where complete combustion is not achieved with the first ignition, or less than half of the larger of the first and second injection amounts. The injection end crank angle during normal operation may be included in the crank angle range in which the intake valve is closed. The injection start crank angle during normal operation may be included in the crank angle range in which the intake valve is closed. The injection end crank angle during short-time intake manifold injection compared to the injection end crank angle during normal operation may be retarded by 60 to 240 crank angles or by 90 to 180 crank angles. This retard amount may be realized during at least a portion of short-time intake manifold injection. The retard amount can be obtained, for example, by comparing the injection end crank angle during short-time intra-intake passage injection with the injection end crank angle during normal driving obtained under the same or substantially the same driving conditions as the injection end crank angle. The driving conditions can be, for example, a combination of engine speed and throttle opening, a combination of vehicle speed and throttle opening, or a combination of engine speed or vehicle speed and throttle opening.

[0020] (2) In the alcohol-containing fuel engine system of (1), the cold start period is at least a part of the period from complete explosion until the inlet temperature of the three-way catalyst reaches 400°C.

[0021] According to the alcohol-containing fuel engine system of (2) above, crank angle control of short-time intake manifold injection is performed during the cold start period, which includes at least a part of the period from complete combustion until the inlet temperature of the three-way catalyst reaches 400° C. Therefore, in an engine in which alcohol-containing fuel is supplied to the intake manifold but direct injection is not performed, both exhaust gas purification performance and cold startability can be achieved at higher levels.

[0022] (3) The alcohol-containing fuel engine system of (1) or (2), wherein the cold start period is at least a portion of a high idle period during cold start.

[0023] According to the alcohol-containing fuel engine system described above in (3), crank angle control of short-time intake manifold injection is performed during a cold start period that includes at least a part of the high idle period during cold start. Therefore, in an engine in which alcohol-containing fuel is supplied to the intake manifold but direct injection is not performed, both exhaust gas purification performance and cold startability can be achieved at higher levels.

[0024] (4) In the alcohol-containing fuel engine system according to any one of (1) to (3), the short-time injection of the alcohol-containing fuel into the intake passage ends at a crank angle that is more advanced than the crank angle at which the intake valve closes.

[0025] According to the alcohol-containing fuel engine system described above in (4), the alcohol-containing fuel can be more efficiently introduced from the intake passage into the combustion chamber, thereby achieving both higher levels of exhaust gas purification performance and cold startability in an engine in which alcohol-containing fuel is supplied to the intake passage but direct injection is not performed.

[0026] (5) In the alcohol-containing fuel engine system according to any one of (1) to (4), the short-time injection of the alcohol-containing fuel into the intake passage is terminated at a crank angle closer to the crank angle at which the intake valve opens than the crank angle at which the intake valve closes.

[0027] According to the alcohol-containing fuel engine system of (5) above, the alcohol-containing fuel can be more efficiently introduced from the intake passage into the combustion chamber, thereby achieving both higher levels of exhaust gas purification performance and cold startability in an engine in which alcohol-containing fuel is supplied to the intake passage but direct injection is not performed.

[0028] (6) In the alcohol-containing fuel engine system according to any one of (1) to (5), the short-time intake passage injection of the alcohol-containing fuel ends at a crank angle closer to the crank angle at which the intake valve opens than the injection start crank angle of the short-time intake passage injection.

[0029] According to the alcohol-containing fuel engine system of (6) above, the alcohol-containing fuel can be more efficiently introduced from the intake passage into the combustion chamber, and therefore, in an engine in which the alcohol-containing fuel is supplied to the intake passage but direct injection is not performed, both exhaust gas purification performance and cold startability can be achieved at higher levels.

[0030] (7) In the alcohol-containing fuel engine system according to any one of (1) to (6), the short-time injection of the alcohol-containing fuel into the intake passage is started at a retarded crank angle so as to be closer to the crank angle at which the intake valve opens than the injection start crank angle during normal operation.

[0031] According to the alcohol-containing fuel engine system of (7) above, the alcohol-containing fuel can be more efficiently introduced from the intake passage into the combustion chamber, thereby achieving both higher levels of exhaust gas purification performance and cold startability in an engine in which alcohol-containing fuel is supplied to the intake passage but direct injection is not performed.

[0032] (8) In the alcohol-containing fuel engine system according to any one of (1) to (7), the short-time injection of the alcohol-containing fuel into the intake passage is performed so that the injection end crank angle is closer to the crank angle range of the valve overlap than the injection start crank angle.

[0033] According to the alcohol-containing fuel engine system of (8) above, the alcohol-containing fuel can be more efficiently introduced from the intake passage into the combustion chamber, thereby achieving both higher levels of exhaust gas purification performance and cold startability in an engine in which alcohol-containing fuel is supplied to the intake passage but direct injection is not performed.

[0034] Valve overlap is the period during which the intake valve and exhaust valve are simultaneously open in an alcohol-containing fuel engine. When the injection end crank angle is within the valve overlap crank angle range, the difference in crank angle between the injection end crank angle and the valve overlap crank angle range is zero. Therefore, when the injection end crank angle is within the valve overlap crank angle range but is not within the valve overlap crank angle range, the injection end crank angle is closer to the valve overlap crank angle range than the injection start crank angle. An alcohol-containing fuel engine does not necessarily need to be configured to generate valve overlap. Furthermore, an alcohol-containing fuel engine may be configured to switch between the presence and absence of valve overlap using variable valve timing. Note that the injection end crank angle may be within the valve overlap crank angle range. This enables more efficient intake of the alcohol-containing fuel from the air passage into the combustion chamber.

[0035] The present invention can provide the following vehicle.

[0036] (9) A vehicle equipped with an alcohol-containing fuel engine system according to any one of (1) to (8).

[0037] According to the vehicle of (9) above, the alcohol-containing fuel can be more efficiently introduced from the intake passage into the combustion chamber. Therefore, in a vehicle equipped with an engine in which the alcohol-containing fuel is supplied to the intake passage but direct injection is not performed, both exhaust gas purification performance and cold startability can be achieved at higher levels.

[0038] A vehicle is a device for transportation. A vehicle is configured to operate in a manned or unmanned (automated) manner. A vehicle can be a personal transportation vehicle. For example, a vehicle may be a public transportation vehicle such as a bus. Examples of personal transportation vehicles include automobiles and saddle-type vehicles. A vehicle may or may not have wheels. Examples of vehicles without wheels include ships with propellers, drones and helicopters with propellers, snowmobiles, and watercraft. A vehicle may or may not have a cabin. Examples of vehicles with a cabin include automobiles and helicopters. One example of a vehicle is a saddle-type vehicle. A saddle-type vehicle is a vehicle equipped with a saddle-type seat. A saddle-type vehicle is a vehicle configured so that a passenger sits astride a saddle. The saddle-type vehicle is not limited to scooter-type, moped-type, off-road-type, and on-road-type motorcycles, but also includes snowmobiles, watercraft, all-terrain vehicles (ATVs), etc. The saddle-type vehicle may have at least one front wheel and at least one rear wheel. The saddle-type vehicle is not limited to motorcycles, but may be a three-wheeled vehicle having a pair of front or rear wheels, or a four-wheeled vehicle having a pair of front and rear wheels, respectively. The saddle-type vehicle may be configured to be able to turn in a lean position toward the inside of a curve. Saddle-type vehicles that can turn in a lean position require agility, so responsiveness in traveling to a starting operation by the rider and acceleration performance at the time of starting are important. In a saddle-type vehicle that can turn in a lean position, high responsiveness to a starting operation contributes to handling stability at the time of starting. The alcohol-containing fuel engine system of the present invention can achieve both exhaust gas purification performance and cold startability, and therefore can be suitably applied to saddle-ride vehicles that are configured to be able to turn in a lean position. Saddle-ride vehicles that are configured to be able to turn in a lean position are suitable as vehicles for the present invention. Other examples of vehicles include golf cars, tracked snowmobiles, and snowplows.

[0039] According to the present invention, it is possible to provide an alcohol-containing fuel engine system that can achieve both exhaust gas purification performance and cold startability in an engine in which alcohol-containing fuel is supplied to the intake passage but in-cylinder injection is not performed, and a vehicle equipped with the same.

[0040] Fig. 1(a) is a block diagram showing a schematic diagram of an alcohol-containing fuel engine system according to one embodiment. Fig. 1(b) is a diagram for explaining control executed in the alcohol-containing fuel engine system. Fig. 1(c) is a chart for explaining an example of control executed in the alcohol-containing fuel engine system. Fig. 2 is a chart for explaining an example of control executed in the alcohol-containing fuel engine system.

[0041] FIG. 1( a ) is a block diagram that schematically illustrates an alcohol-containing fuel engine system 1 according to one embodiment.

[0042] The alcohol-containing fuel engine system 1 includes an alcohol-containing fuel engine 2 , an ECU 3 , and a three-way catalyst 4 .

[0043] The alcohol-containing fuel engine 2 uses an alcohol-containing fuel. In this embodiment, the alcohol-containing fuel engine system 1 is mounted on a vehicle 20. The alcohol-containing fuel engine system 1 is configured to be able to output power generated by the alcohol-containing fuel engine 2 to the outside of the alcohol-containing fuel engine system 1. The vehicle 20 is configured to be able to run using the power generated by the alcohol-containing fuel engine 2. Although not shown, the vehicle 20 is configured so that power is transmitted from the crankshaft of the alcohol-containing fuel engine 2 to wheels via a powertrain.

[0044] The ECU 3 corresponds to a control device. The ECU 3 controls at least the alcohol-containing fuel engine 2. The ECU 3 includes a processor 3 a, a RAM 3 b, a ROM 3 c, and a communication I / F 3 d (interface). The communication I / F 3 d is hardware configured to communicate with sensors and devices within the system 1.

[0045] The three-way catalyst 4 is provided in an exhaust passage 8 of the alcohol-containing fuel engine 2 .

[0046] The alcohol-containing fuel engine 2 includes at least one cylinder 5. In this embodiment, the alcohol-containing fuel engine 2 is a single-cylinder engine. However, the number of cylinders of the alcohol-containing fuel engine 2 is not particularly limited.

[0047] The alcohol-containing fuel engine 2 includes, for each cylinder, a combustion chamber 6, an intake passage 7, an intra-intake passage injection device 9, and an alcohol-containing fuel ignition device 10.

[0048] The combustion chamber 6 is configured so that an alcohol-containing fuel mixture is burned therein. Injection of the alcohol-containing fuel (so-called in-cylinder injection) is not performed in the combustion chamber 6. The combustion chamber 6 is in communication with both an intake passage 7 and an exhaust passage 8. An intake valve 12 is provided between the combustion chamber 6 and the intake passage 7. An exhaust valve 13 is provided between the combustion chamber 6 and the exhaust passage 8.

[0049] The intake passage 7 is made up of an intake port portion 7a located inside the cylinder block of the cylinder 5 and an intake pipe 7b located outside the cylinder block.

[0050] The inter-intake passage injection device 9 is connected to an alcohol-containing fuel tank 11, and is configured to inject the entire amount of alcohol-containing fuel supplied to the inside of the combustion chamber 6 into the intake passage 7. The alcohol-containing fuel injected into the intake passage 7 becomes a mixture with air, and is taken into the combustion chamber 6. The inter-intake passage injection device 9 is controlled by the ECU 3.

[0051] The alcohol-containing fuel ignition device 10 is configured to ignite the alcohol-containing fuel mixture introduced into the combustion chamber 6. The alcohol-containing fuel ignition device 10 is controlled by the ECU 3.

[0052] The alcohol-containing fuel engine 2 includes an exhaust passage 8. The exhaust passage 8 is made up of an exhaust port 8a located inside the cylinder block of the cylinder 5 and an exhaust pipe 8b located outside the cylinder block.

[0053] Next, a description will be given of the control executed by the ECU 3 when starting the alcohol-containing fuel engine 2. The starting operation of the alcohol-containing fuel engine 2 progresses in the following order in terms of time: a starting initial period, a cold start period, and a normal operation period.

[0054] When starting the alcohol-containing fuel engine 2, the ECU 3 rotates the crankshaft (not shown) of the alcohol-containing fuel engine 2, for example, by controlling a starter motor (not shown). This starts a starting period. As the crankshaft rotates, the ECU 3 starts injecting alcohol-containing fuel into the intake passage 7 using the intake passage injection device 9. Furthermore, the ECU 3 starts igniting the alcohol-containing fuel mixture taken into the combustion chamber 6 using the alcohol-containing fuel ignition device 10. This brings the alcohol-containing fuel engine 2 to a complete combustion. The starting period is the period from when the crankshaft begins to rotate until complete combustion.

[0055] Fig. 1(b) is a diagram for explaining control executed in the alcohol-containing fuel engine system 1. Fig. 1(c) is a chart for explaining an example of control executed in the alcohol-containing fuel engine system 1. In the diagram, IVO is the crank angle range in which the intake valve 12 is open. EVO is the crank angle range in which the exhaust valve 13 is open.

[0056] The ECU 3 performs the following controls during at least a part of the cold start period after complete combustion: Ｃ is the ignition crank angle (IGN) during normal operation. ＷThe timing is advanced toward the MBT more than the initial timing. Although this advance increases the output torque of the alcohol-containing fuel engine 2, the alcohol-containing fuel engine system 1 performs the following control to at least partially offset the torque increase due to the advance. The intake passage injection amount of alcohol-containing fuel per cycle is set to be less than the average intake passage injection amount per cycle during the start-up period, within a range in which the exhaust air-fuel ratio does not become leaner than stoichiometric. This makes it possible to inject alcohol-containing fuel into the intake passage for a short time. The short-time intake passage injection is performed within the intake passage injection period (INJ) in one cycle. Ｃ -INE Ｃ ) is the average intake passage injection period per cycle during the start period (INJ Ｓ -INE Ｓ The short-time injection of the alcohol-containing fuel into the intake passage is set to be shorter than the injection end crank angle INE during normal operation. Ｗ The crank angle IVO at which the intake valve 12 opens is Ｉ The crank angle is retarded to be close to Ｃ In this embodiment, the cold start period ends when the inlet temperature of the three-way catalyst 4 reaches 400° C. However, the cold start period may also end when the high idle period ends.

[0057] In this way, in the alcohol-containing fuel engine system 1, the ignition crank angle, the intake passage injection amount, the intake passage injection period, and the injection end crank angle are controlled as shown in Figures 1(b) and 1(c). As a result, the short-time intake passage injection of the alcohol-containing fuel is performed at a retarded crank angle INE while obtaining an output torque for realizing a quick cold start. Ｃ This allows the alcohol-containing fuel injected in the intake passage 7 to be efficiently taken into the combustion chamber 6 from the intake passage 7, and also allows the alcohol-containing fuel to be effectively burned in the combustion chamber 6.

[0058] 2 is a chart illustrating an example of control executed in the alcohol-containing fuel engine system 1. In addition to the above-described controls, the ECU 3 can also perform at least one of the following controls (i) to (v) during at least a portion of the cold start period after complete combustion. The following controls (i) to (v) enable the alcohol-containing fuel supplied to the intake passage 7 by short-time intra-intake passage injection to be more efficiently taken from the intake passage 7 into the combustion chamber 6. This makes it possible to more effectively combust the alcohol-containing fuel in the combustion chamber 6.

[0059] As shown in (i) of the figure, the short-time injection of the alcohol-containing fuel into the intake passage is performed at a crank angle IVO at which the intake valve 12 closes. Ｅ More advanced crank angle than Ｃ The process may be controlled to end at

[0060] As shown in (ii) of the figure, the short-time injection of the alcohol-containing fuel into the intake passage is performed at a crank angle IVO at which the intake valve 12 closes. Ｅ The crank angle IVO at which the intake valve 12 opens is Ｉ Crank angle close to INE Ｃ That is, the crank angle range (INE Ｃ -IVO Ｉ ) < Crank angle range (INE Ｃ -IVO Ｅ ) may be controlled to hold.

[0061] As shown in (iii) of the figure, the short-time injection of the alcohol-containing fuel into the intake passage is performed at an injection start crank angle INJ Ｃ The crank angle IVO at which the intake valve 12 opens is Ｉ Crank angle close to INE Ｃ That is, the crank angle range (INE Ｃ -IVO Ｉ ) < Crank angle range (INE Ｃ -INJ Ｃ ) may be controlled to hold.

[0062] As shown in (iv) of the figure, the short-time injection of the alcohol-containing fuel into the intake passage is performed at an injection start crank angle INJ Ｗ The crank angle IVO at which the intake valve 12 opens is Ｉ The retarded crank angle INJ Ｃ That is, the engine may be controlled to start at a retarded crank angle INJ Ｃ is within the crank angle range (INJ Ｃ -IVO Ｉ ) < Crank angle range (INJ Ｗ -IVO Ｉ ) may be controlled to satisfy

[0063] As shown in (v) of the figure, the short-time injection of the alcohol-containing fuel into the intake passage is performed at an injection end crank angle INE. Ｃ However, the injection start crank angle INJ Ｃ Rather than the valve overlap VOL crank angle range (IVO Ｉ -EVO Ｅ ) may be implemented.

[0064] The present invention is not limited to the above-described embodiment, but may be embodied in other embodiments and may be modified in various ways.

[0065] 1: Alcohol-containing fuel engine system 2: Alcohol-containing fuel engine 3: ECU 3a: Processor 3b: RAM 3c: ROM 3d: Communication I / F 4: Three-way catalyst 5: Cylinder 6: Combustion chamber 7: Intake passage 7a: Intake port 7b: Intake pipe 8: Exhaust passage 8a: Exhaust port 8b: Exhaust pipe 9: Intake passage injection device 10: Alcohol-containing fuel ignition device 11: Alcohol-containing fuel tank 12: Intake valve 13: Exhaust valve 20: Vehicle INJ Ｓ INE: Injection start crank angle during the starting period (i.e., the period until complete combustion) Ｓ : Injection end crank angle during start-up period INJ Ｃ INE: injection start crank angle during at least a part of the cold start period Ｃ: injection end crank angle during at least a part of the cold start period IGN Ｃ : Ignition crank angle during at least a part of the cold start period INJ Ｗ INE: Injection start crank angle during normal operation Ｗ : Injection end crank angle during normal operation IGN Ｗ : Ignition crank angle during normal operation IVO : Crank angle range in which the intake valve is open IVO Ｉ : Crank angle at which intake valve opens IVO Ｅ : Crank angle EVO at which the intake valve closes : Crank angle range EVO at which the exhaust valve opens Ｅ : Crank angle at which the exhaust valve closes MBT : MBT (Minimum advance for Best Torque) VOL : Valve overlap

Claims

1. An alcohol-containing fuel engine system, wherein the alcohol-containing fuel engine system includes an alcohol-containing fuel engine that uses alcohol-containing fuel, a control device that controls at least the alcohol-containing fuel engine, and a three-way catalyst provided in an exhaust passage of the alcohol-containing fuel engine. The alcohol-containing fuel engine includes at least one cylinder, and for each cylinder, there is a combustion chamber, an intake passage for taking air into the combustion chamber, an in-intake passage injection device configured to inject the entire amount of alcohol-containing fuel supplied into the combustion chamber into the intake passage, and an alcohol-containing fuel ignition device for igniting an alcohol-containing fuel-air mixture of the alcohol-containing fuel and air taken into the combustion chamber. It is configured not to perform in-cylinder injection of the alcohol-containing fuel. The control device controls the alcohol-containing fuel ignition device so that, for at least one cylinder, during at least a part of the cold start period after complete combustion, the ignition crank angle for the alcohol-containing fuel-air mixture is advanced toward MBT compared to the ignition crank angle during normal operation. And within a range where the exhaust air-fuel ratio does not become leaner than stoichiometry, the in-intake passage injection amount of the alcohol-containing fuel per cycle is reduced compared to the average in-intake passage injection amount per cycle until complete combustion, thereby offsetting at least partially the torque increase due to the advance angle, enabling short-time in-intake passage injection of the alcohol-containing fuel where the in-intake passage injection period in one cycle is shorter than the average in-intake passage injection period per cycle until complete combustion, and controls the in-intake passage injection device so that the short-time in-intake passage injection of the alcohol-containing fuel ends at a retarded crank angle closer to the crank angle at which the intake valve opens than the injection end crank angle during normal operation. An alcohol-containing fuel engine system characterized by the above.

2. The alcohol-containing fuel engine system according to claim 1, wherein the cold start period is at least a part of the period from complete combustion until the inlet temperature of the three-way catalyst reaches 400 °C.

3. The alcohol-containing fuel engine system according to claim 1 or 2, wherein the cold start period is at least a part of the high idle period during cold start.

4. The short-time intake passage injection of the alcohol-containing fuel ends at a crank angle advanced from the crank angle at which the intake valve closes, for the alcohol-containing fuel engine system according to any one of claims 1 to 3.

5. The short-time intake passage injection of the alcohol-containing fuel ends at a crank angle closer to the crank angle at which the intake valve opens than the crank angle at which the intake valve closes, for the alcohol-containing fuel engine system according to any one of claims 1 to 4.

6. The short-time intake passage injection of the alcohol-containing fuel ends at a crank angle closer to the crank angle at which the intake valve opens than the injection start crank angle of the short-time intake passage injection, for the alcohol-containing fuel engine system according to any one of claims 1 to 5.

7. The short-time intake passage injection of the alcohol-containing fuel starts at a retarded crank angle so as to be closer to the crank angle at which the intake valve opens than the injection start crank angle during normal operation, for the alcohol-containing fuel engine system according to any one of claims 1 to 6.

8. The short-time intake passage injection of the alcohol-containing fuel is carried out such that the injection end crank angle is closer to the crank angle range of valve overlap than the injection start crank angle, for the alcohol-containing fuel engine system according to any one of claims 1 to 7.

9. A vehicle equipped with the alcohol-containing fuel engine system according to any one of claims 1 to 8.

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