WO2025134183A1 - Alcohol-containing fuel engine system and vehicle - Google Patents

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

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

Patent Document 1 relates to an engine in which alcohol-containing fuel is supplied to the intake path (e.g., claim 1 of Patent Document 1). Patent Document 1 mentions the problem of unburned alcohol fuel, that is, when the catalyst has not yet reached its activation temperature, such as immediately after the engine is started, the unburned alcohol fuel is not sufficiently purified, and the unburned alcohol fuel is discharged outside the engine (e.g., [0005] of Patent Document 1). Patent Document 1 also mentions the compatibility of engine startability when cold and the exhaust gas purification performance of the catalyst (e.g., [0006] to [0007] of Patent Document 1). In response to such a 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 becomes equal to or exceeds a threshold value in an engine in which alcohol-containing fuel is supplied to the intake path. Patent Document 1 gives an example of a three-way catalyst as the catalyst.

JP 2011-153601 A

In engines where alcohol-containing fuel is supplied to the intake passage but direct injection is not performed, it is desirable to achieve both exhaust gas purification performance and cold startability.

The object of the present invention is to provide an alcohol-containing fuel engine system that is capable of achieving 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.

In view of the above problems, the inventors have conducted extensive research into how to efficiently take in alcohol-containing fuel from the intake passage into the combustion chamber while obtaining output torque for achieving a quick cold start in an engine in which alcohol-containing fuel is supplied to the intake passage but in which direct injection is not performed, and have obtained the following findings. That is, the alcohol-containing fuel is reduced to the extent that it does not become lean, in a manner that offsets the increase in output torque obtained by the ignition advance. This enables short-time injection into the intake passage, and this short-time injection into the intake passage is performed with the end crank angle retarded. This achieves efficient intake of the alcohol-containing fuel injected into the intake passage into the combustion chamber while obtaining output torque. Based on this finding, the present invention has been completed. The present invention is a technology relating to the intake of alcohol-containing fuel from the intake passage into the combustion chamber, and is therefore essentially different from technology relating to engines in which direct injection is performed.

The present invention provides the following alcohol-containing fuel engine system.

(1) An alcohol-containing fuel engine system,
The alcohol-containing fuel engine system comprises:
an alcohol-containing fuel engine using an alcohol-containing fuel;
A control device for controlling at least the alcohol-containing fuel engine;
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,
For each cylinder,
A combustion chamber;
an intake passage for introducing air into the combustion chamber;
an intake passage injection device configured to inject a total amount of the alcohol-containing fuel supplied to the combustion chamber into the intake passage;
an alcohol-containing fuel ignition device that ignites an alcohol-containing fuel mixture of the alcohol-containing fuel and air introduced into the combustion chamber, and is configured not to perform in-cylinder injection of the alcohol-containing fuel,
The control device includes:
With respect to at least one cylinder, during at least a portion of a cold start period after a complete combustion,
The alcohol-containing fuel ignition device is controlled so that an ignition crank angle for an alcohol-containing fuel mixture is advanced toward an MBT from an ignition crank angle during normal operation,
an intake passage injection device that controls the intake passage injection device so that the short-time 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 than the injection end crank angle during normal operation, the intake passage injection device controls the intake passage injection device so that the short-time 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, ...

According to the alcohol-containing fuel engine system of (1) above, during at least a part of the cold start period after complete combustion, the control device advances the ignition crank angle for the alcohol-containing fuel mixture toward the MBT, more than the ignition crank angle during normal operation. Advancement of the ignition crank angle increases the output torque of the engine. Furthermore, the control device reduces the amount of alcohol-containing fuel injected into the intake passage per cycle, within a range in which the exhaust air-fuel ratio does not become leaner than stoichiometric, so as to at least partially offset the torque increase caused by the advance. This makes it possible to shorten the injection period of the alcohol-containing fuel into the intake passage in one cycle. In other words, it is possible to perform short-time injection of the alcohol-containing fuel into the intake passage. In addition, the control device controls the intake passage injection device so that the short-time injection of the alcohol-containing fuel into the intake passage ends at a crank angle that is retarded so as to be closer to the crank angle at which the intake valve opens, more than the injection end crank angle during normal operation. As a result, short-time injection of alcohol-containing fuel into the intake passage can be completed at a retarded crank angle while obtaining output torque for achieving a quick cold start. This allows the alcohol-containing fuel injected into the intake passage to be efficiently taken into the combustion chamber from the intake passage, 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 supply of alcohol-containing fuel to the combustion chamber is performed by injection into the intake passage and exhaust gas is treated by a three-way catalyst, exhaust gas with a composition suitable for purification by a three-way catalyst can be generated while obtaining output torque for achieving a quick cold start, and THC (Total Hydrocarbon Content) in the exhaust gas can be suppressed.

The alcohol-containing fuel is a fuel composition containing alcohol as a main component. The main component here means that it is not an impurity or an unavoidable mixture, and for example, it means that it contains at least 1% by volume. The alcohol-containing fuel may contain a hydrocarbon fuel. A hydrocarbon fuel may also be contained as a main component. The alcohol is not particularly limited, and examples thereof include methanol, ethanol, propanol, and butanol. The concentration (volume concentration) of the alcohol may be more than 0% by volume, or may be substantially 100% by volume. The hydrocarbon fuel is not particularly limited, and examples thereof include gasoline. E3, E10, E15, E20, E25, E85, and E100 may be used. E indicates the volume percentage of ethanol in a mixture of gasoline and ethanol. A mixture of a different composition and an equivalent concentration may also be used. There are no particular limitations on the composition and alcohol concentration of the alcohol-containing fuel, as long as it is applicable to an alcohol-containing fuel engine.

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 the upper limit are 3, 10, 15, 20, 25, 85, and 100 by volume. An upper limit of 20% by volume means that the alcohol-containing fuel engine can apply alcohol-containing fuel with an alcohol concentration of up to 20% by volume. The higher the upper limit, the higher the alcohol-containing fuel concentration that can be applied. An alcohol-containing fuel engine may be configured such 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 capable of applying a hydrocarbon fuel (e.g., gasoline) that does not contain alcohol. The alcohol concentration of the applicable alcohol-containing fuel is not particularly limited as long as it is within the range of the upper and lower limits described above. In addition, with regard to the number of cylinders, an alcohol-containing fuel engine includes, for example, a single-cylinder engine and an engine having 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 in all cylinders. If the control according to the present invention is performed in any one cylinder, the engine system corresponds to the alcohol-containing fuel system according to the present invention.

The control device is composed of a computer having a processor, a RAM, and a 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 a plurality of sensors provided in the system, and outputs commands for controlling various devices in the system. The RAM functions as a memory area for temporary data storage. Examples of temporary data include data being processed and data from the sensors. The data from the sensors include 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-containing fuel engine. The control device controls an intake passage injection device and an alcohol-containing fuel ignition device in the engine. The control device may also control devices other than the alcohol-containing fuel engine. The control device may be composed of a single device, or may be composed of a plurality of devices physically separated from each other. Since the control device controls an alcohol-containing fuel engine, values different from those of a gasoline engine are used, for example, in adjusting the fuel injection amount, ignition timing, and fuel mixture ratio. The present invention solves problems specific to alcohol-containing fuel engines.

The 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 precious 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.

The 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 dedicated device for alcohol-containing fuel, or a general-purpose device that is also used for gasoline fuel. The device may be selected according to the alcohol concentration of the alcohol-containing fuel. Note that in-cylinder injection is not performed in an alcohol-containing fuel engine.

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 fuels, but can be a general-purpose device that can also be used for gasoline fuel.

Complete combustion refers to a state in which the crankshaft is driven autonomously 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 until 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 can be expressed as, for example, the injection amount of the i-th ignition as I _(i) , and when complete combustion is achieved by the N-th ignition, the average intake passage injection amount can be expressed as (1/N)Σ(i=1 to N)I _(i) (where i is an integer from 1 to N).

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

MBT (Minimum advance for Best Torque) is the ignition advance point in an alcohol-fueled engine at which the torque of the alcohol-fueled engine is at its maximum.

The injection amount per cycle in the short-time intake passage injection is less than the average 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 by 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 retard amount of the injection end crank angle during the short-time intake passage injection compared to the injection end crank angle during normal operation may be 60 to 240 crank angles, or may be 90 to 180 crank angles. The retard amount may be realized during at least a part of the short-time intake passage injection. The retard amount is obtained, for example, by comparing the injection end crank angle during short-time injection into the intake passage 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. As the driving conditions, 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 can be used.

(2) An engine system for an alcohol-containing fuel according to (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.

According to the alcohol-containing fuel engine system described above in (2), crank angle control of short-time injection into the intake passage is performed during the cold start period, which includes at least a portion of the period from complete explosion 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 passage but in-cylinder injection is not performed, both exhaust gas purification performance and cold startability can be achieved at a higher level.

(3) An engine system using an alcohol-containing fuel according to (1) or (2),
The cold start period is at least a portion of a high idle period during a cold start.

According to the above-mentioned (3) alcohol-containing fuel engine system, crank angle control of short-time injection into the intake passage is performed during the cold start period, which 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 passage but in-cylinder injection is not performed, both exhaust gas purification performance and cold startability can be achieved at a higher level.

(4) 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.

The above-mentioned (4) alcohol-containing fuel engine system enables more efficient intake of the alcohol-containing fuel from the air passage into the combustion chamber. Therefore, in an engine in which alcohol-containing fuel is supplied to the intake passage but in-cylinder injection is not performed, both exhaust gas purification performance and cold startability can be achieved at a higher level.

(5) 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 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.

The above-mentioned (5) alcohol-containing fuel engine system enables more efficient intake of alcohol-containing fuel from the air passage into the combustion chamber. Therefore, in an engine in which alcohol-containing fuel is supplied to the intake passage but in-cylinder injection is not performed, both exhaust gas purification performance and cold startability can be achieved at a higher level.

(6) The alcohol-containing fuel engine system according to any one of (1) to (5),
The short duration 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 duration intake passage injection.

The alcohol-containing fuel engine system described above in (6) enables more efficient intake of the alcohol-containing fuel from the air passage into the combustion chamber. Therefore, in an engine in which alcohol-containing fuel is supplied to the intake passage but in-cylinder injection is not performed, both exhaust gas purification performance and cold startability can be achieved at a higher level.

(7) 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.

The above-mentioned (7) alcohol-containing fuel engine system enables more efficient intake of alcohol-containing fuel from the air passage into the combustion chamber. Therefore, in an engine in which alcohol-containing fuel is supplied to the intake passage but in-cylinder injection is not performed, both exhaust gas purification performance and cold startability can be achieved at a higher level.

(8) 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.

The above-mentioned (8) alcohol-containing fuel engine system enables more efficient intake of the alcohol-containing fuel from the air passage into the combustion chamber. Therefore, in an engine in which alcohol-containing fuel is supplied to the intake passage but in-cylinder injection is not performed, both exhaust gas purification performance and cold startability can be achieved at a higher level.

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 included in 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 included in the valve overlap crank angle range, but is not included in 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. In addition, an alcohol-containing fuel engine may be configured to switch between the presence and absence of valve overlap by variable valve timing. The injection end crank angle may be included in the valve overlap crank angle range. This allows for more efficient intake of the alcohol-containing fuel from the ventilation passage into the combustion chamber.

The present invention can provide the following vehicles:

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

The vehicle described in (9) above allows the alcohol-containing fuel to be more efficiently introduced from the air passage into the combustion chamber. Therefore, in a vehicle equipped with an engine in which alcohol-containing fuel is supplied to the intake passage but in-cylinder injection is not performed, both exhaust gas purification performance and cold startability can be achieved at a higher level.

A vehicle is a device for transportation. A vehicle is configured so that its operation can be manned or unmanned (automated). 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 rides in a position astride a saddle. The saddle-type vehicle is not limited to a scooter-type, moped-type, off-road-type, or on-road-type motorcycle, but includes a snowmobile, a watercraft, an all-terrain vehicle (ATV), and the like. 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 a motorcycle, but may be a three-wheeled vehicle in which the front or rear wheels are a pair of left and right wheels, or a four-wheeled vehicle in which the front and rear wheels are a pair of left and right wheels, respectively. The saddle-type vehicle may be configured to be able to turn in a lean position toward the inside of a curve. Since lightness is required for a saddle-type vehicle that can turn in a lean position, importance is attached to the responsiveness of the progress to a starting operation by the rider and the acceleration performance at the time of starting. In a saddle-type vehicle configured to be able to turn in a lean position, high responsiveness to a starting operation contributes to the handling stability at the time of starting. The alcohol-containing fuel engine system of the present invention is capable of achieving both exhaust gas purification performance and cold startability, and is therefore suitable for use in saddle-type vehicles that are configured to be able to turn in a lean position. Saddle-type 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, caterpillar-type snowmobiles, and snowplows.

The present invention provides an alcohol-containing fuel engine system that is capable of achieving 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.

Fig. 1(a) is a block diagram showing an outline of an alcohol-containing fuel engine system according to an 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 an engine system using a fuel containing alcohol.

FIG. 1(a) is a block diagram showing an outline of an alcohol-containing fuel engine system 1 according to one embodiment.

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

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 the 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 the wheels via a powertrain.

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 3a, a RAM 3b, a ROM 3c, and a communication I/F 3d (interface). The communication I/F 3d is hardware configured to communicate with sensors and devices within the system 1.

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

The alcohol-containing fuel engine 2 has 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.

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

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 connected to both the intake passage 7 and the 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.

The intake passage 7 consists 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.

The 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 intake passage injection device 9 is controlled by the ECU 3.

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.

The alcohol-containing fuel engine 2 has an exhaust passage 8. The exhaust passage 8 consists of an exhaust port 8a located inside the cylinder block of the cylinder 5 and an exhaust pipe 8b located outside the cylinder block.

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

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 the start-up 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 explosion. The start-up period is the period from when the crankshaft begins to rotate to when complete explosion occurs.

FIG. 1(b) is a diagram for explaining the control executed in the alcohol-containing fuel engine system 1. FIG. 1(c) is a chart for explaining an example of the 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.

The ECU 3 performs the following control during at least a part of the cold start period after complete explosion. The ignition crank angle IGN _C is advanced toward the MBT from the ignition crank angle IGN _W during the normal operation period. Although the output torque of the alcohol-containing fuel engine 2 increases due to this advance, 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 the alcohol-containing fuel per cycle is set to be less than the average intake passage injection amount per cycle during the start start period, within a range in which the exhaust air-fuel ratio does not become leaner than stoichiometric. This enables short-time intake passage injection of the alcohol-containing fuel. The short-time intake passage injection is set so that the intake passage injection period (INJ _C -INE _C ) during one cycle is shorter than the average intake passage injection period (INJ _S -INE _S ) during one cycle during the start start period. The short-time injection of the alcohol-containing fuel into the intake passage ends at a crank angle INE _C that is retarded so as to be closer to the crank angle IVO _I at which the intake valve 12 opens than the injection end crank angle INE _W during normal operation. 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 at the end of the high idle period.

In this manner, 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). This makes it possible to obtain an output torque for realizing a quick cold start, while executing the short-time intake passage injection of the alcohol-containing fuel so as to end at the retarded crank angle INE _C. This makes it possible to efficiently take the alcohol-containing fuel injected in the intake passage 7 from the intake passage 7 into the combustion chamber 6, and to effectively combust the alcohol-containing fuel in the combustion chamber 6.

FIG. 2 is a chart for explaining an example of control executed in the alcohol-containing fuel engine system 1. In addition to the above-mentioned 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 explosion. The following controls (i) to (v) make it possible to more efficiently take in the alcohol-containing fuel supplied to the intake passage 7 by short-time intake passage injection from the intake passage 7 into the combustion chamber 6. This makes it possible to more effectively burn the alcohol-containing fuel in the combustion chamber 6.

As shown in (i) in the figure, the short-time injection of the alcohol-containing fuel into the intake passage may be controlled to end at a crank angle INE _C that is advanced from the crank angle IVO _E at which the intake valve 12 closes.

As shown in (ii) in the figure, the short-time injection of the alcohol-containing fuel into the intake passage may be controlled to end at a crank angle INE _C that is closer to the crank angle IVO _I at which the intake valve 12 opens than to the crank angle IVO _E at which the intake valve 12 closes. In other words, the crank angle range (INE _C - IVO _I ) < crank angle range (INE _C - IVO _E ) may be satisfied.

As shown in (iii) in the figure, the short duration intake passage injection of the alcohol-containing fuel may be controlled to end at a crank angle INE _C that is closer to the crank angle IVO _I at which the intake valve 12 opens than the injection start crank angle INJ _C of the short duration intake passage injection. In other words, the crank angle range (INE _C - IVO _I ) < crank angle range (INE _C - INJ _C ) may be satisfied.

As shown in (iv) in the figure, the short-time injection of the alcohol-containing fuel into the intake passage may be controlled to start at a retarded crank angle INJ _C so as to be closer to the crank angle IVO _I at which the intake valve 12 opens than the injection start crank angle INJ _W during normal operation. In other words, the retarded crank angle INJ _C may be controlled to satisfy the crank angle range (INJ _C - IVO _I ) < crank angle range (INJ _W - IVO _I ).

As shown in (v) in the figure, the short-time injection of the alcohol-containing fuel into the intake passage may be performed so that the injection end crank angle INE _C is closer to the crank angle range (IVO _I -EVO _E ) of the valve overlap VOL than the injection start crank angle INJ _C.

The present invention is not limited to the embodiment described above. The present invention can be implemented in other embodiments, and various modifications can be added.

1: Alcohol-containing fuel engine system 2: Alcohol-containing fuel engine 3: ECU
3a: Processor 3b: RAM
3c: ROM
3d: Communication I/F
Description of the Reference Number 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: Ignition device for alcohol-containing fuel 11: Alcohol-containing fuel tank 12: Intake valve 13: Exhaust valve 20: Vehicle INJ _S : Injection start crank angle INE _S during the start-up period (i.e., the period until complete explosion): Injection end crank angle INJ _C during the start-up period: Injection start crank angle INE _C during at least a portion of the cold start period: Injection end crank angle IGN _C during at least a portion of the cold start period: Ignition crank angle INJ _W during at least a portion of the cold start period: Injection start crank angle INE _W during the normal operation period: Injection end crank angle IGN _W during the normal operation period IVO: Ignition crank angle during normal operation IVO: Crank angle range IVO where the intake valve is open IVO _I : Crank angle IVO where the intake valve is open _E : Crank angle EVO where the intake valve is closed EVO: Crank angle range EVO where the exhaust valve is open EVO _E : Crank angle EVO where the exhaust valve is closed MBT: MBT (Minimum advance for Best Torque)
VOL: Valve overlap

Claims (9)

1. An alcohol-containing fuel engine system, comprising:
The alcohol-containing fuel engine system comprises:
an alcohol-containing fuel engine using an alcohol-containing fuel;
A control device for controlling at least the alcohol-containing fuel engine;
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,
For each cylinder,
A combustion chamber;
an intake passage for introducing air into the combustion chamber;
an intake passage injection device configured to inject a total amount of the alcohol-containing fuel supplied to the combustion chamber into the intake passage;
an alcohol-containing fuel ignition device that ignites an alcohol-containing fuel mixture of the alcohol-containing fuel and air introduced into the combustion chamber, and is configured not to perform in-cylinder injection of the alcohol-containing fuel,
The control device includes:
With respect to at least one cylinder, during at least a portion of a cold start period after a complete combustion,
The alcohol-containing fuel ignition device is controlled so that an ignition crank angle for an alcohol-containing fuel mixture is advanced toward an MBT from an ignition crank angle during normal operation,
an intake passage injection device that controls the intake passage injection device so that the short-time 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 than the injection end crank angle during normal operation, the intake passage injection device controls the intake passage injection device so that the short-time 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, ... The cold start period is at least a part of the period from complete explosion to when the inlet temperature of the three-way catalyst reaches 400°C.
2. The alcohol-containing fuel engine system of claim 1. the cold start period being at least a portion of a high idle period during a cold start;
3. An engine system using an alcohol-containing fuel according to claim 1 or 2. the short-time injection of the alcohol-containing fuel into the intake passage is terminated at a crank angle that is more advanced than the crank angle at which the intake valve is closed;
4. An engine system using an alcohol-containing fuel according to claim 1. 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.
5. An engine system using an alcohol-containing fuel according to claim 1. 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 an injection start crank angle of the short-time intake passage injection.
6. An engine system using an alcohol-containing fuel according to claim 1. 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.
An engine system using an alcohol-containing fuel according to any one of claims 1 to 6. the short-time injection of the alcohol-containing fuel into the intake passage is performed so that an injection end crank angle is closer to a valve overlap crank angle range than an injection start crank angle;
An engine system using an alcohol-containing fuel according to any one of claims 1 to 7. A vehicle equipped with an alcohol-containing fuel engine system according to any one of claims 1 to 8.

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