JP7439644B2 - fuel supply device - Google Patents

Description

The present invention relates to a fuel supply device.

Conventionally, the engine is configured to be able to use gaseous fuel and liquid fuel, and there is a known technology that actively uses liquid fuel when starting the engine to ensure engine startability (for example, Patent Document 1) reference).

Japanese Patent Application Publication No. 11-324749

However, in the above-mentioned conventional technology, since liquid fuel is actively used when starting the engine, gaseous fuel is used less frequently. Generally, gaseous fuels are known to have higher thermal efficiency than liquid fuels, so there is room to improve thermal efficiency by selecting the fuel when starting the engine.

Therefore, the present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a fuel supply device that can improve fuel efficiency while ensuring engine startability.

A fuel supply device according to one embodiment is a fuel supply device capable of supplying liquid fuel and gaseous fuel to an engine installed in a vehicle, and automatically stops the engine based on an automatic stop condition. and a control unit configured to stop the engine and restart the engine based on a restart condition, and the control unit includes a control unit configured to stop the engine and restart the engine based on a restart condition, and the control unit controls whether the engine is supplied with the engine if the engine is not rotating when the restart condition is satisfied. The gist is that the liquid fuel is selected as the fuel, and if the engine is rotating, the gaseous fuel is selected as the fuel to be supplied to the engine.

FIG. 1 is a schematic diagram for explaining a vehicle system according to an embodiment. FIG. 2 is a flowchart for explaining operations according to one embodiment. FIG. 3 is a timing chart for explaining the operation of the ECU 3 according to this embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. In addition, in the description of the following drawings, the same or similar parts are given the same or similar symbols. However, it should be noted that the drawings are schematic and the ratio of each dimension is different from the actual one. Therefore, specific dimensions etc. should be determined with reference to the following explanation. Furthermore, the drawings may include portions with different dimensional relationships and ratios. In this specification and the drawings, elements having substantially the same functions and configurations are designated by the same reference numerals to omit redundant explanation, and elements not directly related to the present invention are omitted from illustration.

(1) Schematic configuration of vehicle system The schematic configuration of a vehicle system 1 according to an embodiment will be described using FIG. 1. FIG. 1 is a schematic diagram for explaining a vehicle system 1 according to an embodiment.

The vehicle system 1 is included in a vehicle having an engine 2 configured to be able to use liquid fuel and gaseous fuel.

As shown in FIG. 1, a vehicle system 1 (vehicle) includes an engine 2, an ECU (Engine Control Unit) 3, a fuel tank 4, a fuel switching device 5, an intake manifold 6, a starter 7, and drive wheels. 8, a clutch 9, a transmission 10, a pedal 11, a water temperature sensor 12, a vehicle speed sensor 13, a fuel selection switch 14, an injector 15, a solenoid valve 16, and an IS (Idling Stop) prohibition switch 20. has.

The engine 2 is a device that serves as a power source for the drive wheels 8. Engine 2 is controlled by ECU3. In the engine 2, fuel stored in a fuel tank 4 (described later) is injected by an injector 15, and the injected fuel is combusted to generate power for the drive wheels 8.

ECU 3 is a device (control device) for controlling engine 2 . ECU 3 controls engine 2, fuel switching device 5, and starter 7. Specifically, the ECU 3 transmits and receives electrical signals to and from the engine 2 and the fuel switching device 5. The ECU 3 controls the starter 7 by transmitting an electric signal to the starter 7. ECU 3 can control engine 2 via starter 7 .

The ECU 3 may include a processor, a memory, and a transceiver. The processor and memory may constitute a control unit. The processor includes a CPU (Central Processing Unit). The processor performs various processes described below by executing programs stored in the memory. Memory stores programs executed by the processor and information used in processing by the processor. The transceiver transmits and receives electrical signals to and from various devices controlled by the processor (for example, the engine 2, the fuel switching device 5, etc.). The transceiver receives electrical signals from various devices and outputs them to the processor. Furthermore, the transceiver transmits electrical signals input from the processor to various devices.

ECU 3 receives electrical signals from pedal 11 , water temperature sensor 12 , vehicle speed sensor 13 , fuel selection switch 14 , and IS prohibition switch 20 . ECU 3 can control engine 2, fuel switching device 5, and starter 7 according to the received electrical signals.

The fuel tank 4 is a tank (container) that stores fuel. Specifically, the fuel tank 4 includes a first fuel tank 41 and a second fuel tank 42. The first fuel tank 41 stores liquid fuel. The liquid fuel is, for example, gasoline or light oil. The second fuel tank 42 accommodates gaseous fuel. The gaseous fuel is, for example, CNG (Compressed Natural Gas) or LPG (Liquefied Natural Gas).

The fuel switching device 5 is a device that switches fuel to be sent to the engine 2. The fuel switching device 5 is connected to a first fuel tank 41 and a second fuel tank 42. The fuel switching device 5 sends the fuel selected by the ECU 3 to the engine 2.

Intake manifold 6 is arranged between fuel switching device 5 and engine 2. Fuel sent from the fuel switching device 5 is sent to the engine 2 through an intake manifold 6. Fuel from the fuel switching device 5 is injected into the intake manifold 6. As a result, fuel is injected into the fuel chamber of the engine 2.

The starter 7 is a device that starts the engine 2. The starter 7 is started by an electric signal from the ECU 3 and starts the engine 2. By starting the engine 2, the starter 7 raises the temperature of the engine 2 and brings the engine 2 into a completely warmed up state.

The drive wheels 8 are driven (rotated) using the engine 2 as a power source. Clutch 9 transmits power from engine 2 to transmission 10. The clutch 9 may be operated by a clutch pedal 116, which will be described later. The clutch 9 may be automatically controlled without any operation by the driver. The transmission 10 changes the speed of the power from the engine 2 and transmits it to the drive wheels 8.

The pedal 11 transmits the driver's operation to the ECU 3 by an electric signal. The pedals 11 include an accelerator pedal 112 and a brake pedal 114. The pedal 11 may have a clutch pedal 116 or may not have a clutch pedal 116.

Water temperature sensor 12 measures the water temperature of engine 2 . The water temperature sensor 12 can send a measured value to the ECU 3 as an electrical signal. Vehicle speed sensor 13 measures the speed of the vehicle (vehicle speed). The vehicle speed sensor 13 can send a measured value to the ECU as an electrical signal.

The fuel selection switch 14 is a switch operated by the driver. The fuel selected by the driver's operation is transmitted to the ECU 3 by an electric signal.

The IS prohibition switch 20 is a switch operated by the driver. The IS prohibition is transmitted to the EMC3 by an electric signal by the driver's operation.

An injector (fuel injection device) 15 injects fuel into the intake manifold 6. The injector 15 may be controlled by the ECU 3. The injector 15 may be controlled by the driver's operation (eg, depression of the accelerator pedal 112/release of the brake pedal 114).

The solenoid valve 16 is arranged between the first fuel tank 41 and the injector 15 in a path through which liquid fuel passes. In FIG. 1 , the solenoid valve 16 is arranged between the first fuel tank 41 and the fuel switching device 5 .

The solenoid valve 16 is opened or closed by an electric signal (omitted) from the ECU 3. When the solenoid valve 16 is open, liquid fuel can pass through the path and reach the injector 15. On the other hand, when the electromagnetic valve 16 is closed, liquid fuel cannot pass through the path, and gaseous fuel can reach the injector 15.

Note that a vehicle equipped with the vehicle system 1 may include a sensor (not shown) that measures the state of a battery (for example, a lead battery) of the vehicle. Such sensors can measure battery voltage, battery fluid temperature, and/or battery state of charge.

Furthermore, a vehicle equipped with the vehicle system 1 can select gaseous fuel instead of liquid fuel during normal driving. Thereby, fuel efficiency can be improved.

Here, the above-described fuel switching device 5, injector 15, intake manifold 6, and ECU 3 constitute a fuel supply device that can supply liquid fuel and gaseous fuel to the engine 2 provided in the vehicle 1.

(2) Operation according to the embodiment The operation according to the embodiment will be explained using FIG. 2. FIG. 2 is a flowchart for explaining the operation according to the embodiment.

In addition, in FIG. 2, it is assumed that the engine 2 is in operation and in a state (completely warmed up state) in which gaseous fuel has good startability. The fully warmed up state is a state in which when the engine 2 is started using gaseous fuel, the engine 2 can actually start (the rotational speed of the engine 2 increases) within a predetermined time.

As shown in FIG. 2, in step S1, the ECU 3 determines whether or not the engine 2 is in an automatic stop state where the engine 2 is automatically stopped. The automatic stop state is a state in which the engine 2 continues to operate at a minimum rotational speed in an unloaded state, which is a state in which idling is stopped (idling stop).

Note that the idling stop includes an idling stop when the vehicle is stopped and an idling stop when the vehicle is decelerating. Idling stop when the vehicle is stopped means a state in which the engine 2 is automatically stopped after the vehicle has stopped (that is, when V=0). Idling stop during deceleration refers to a state in which the engine 2 is automatically stopped when the vehicle speed V becomes equal to or less than a predetermined speed while the vehicle is decelerating (that is, when V>0).

The ECU 3 can determine whether or not the engine 2 is in an automatic stop state, in which the engine 2 is automatically stopped, based on the automatic stop condition. That is, the ECU 3 can determine that the engine 2 is in the automatic stop state when the automatic stop condition is satisfied.

For example, the ECU 3 may determine that the automatic stop condition is satisfied when the driver releases the accelerator pedal 112.

In addition, the ECU3 is used in AT (Automatic Transmission) vehicles, CVT (Continuously Variable Transmission) vehicles, AMT (Automatic Manual Transmission) vehicles, and DCT (Dual Cluster) vehicles. tch Transmission) In a vehicle, when the brake pedal 114 is depressed by the driver, It may be determined that the automatic stop condition is satisfied.

Furthermore, in a manual transmission (MT) vehicle, the ECU 3 may determine that the automatic stop condition is satisfied when the driver releases the clutch and shifts the gear to neutral (N).

Furthermore, the ECU 3 may determine that the automatic stop condition is satisfied when the vehicle speed becomes equal to or lower than a predetermined speed.

The ECU 3 may determine that the automatic stop state is present, taking into consideration the battery liquid temperature, the charging state of the battery, and the like.

When the ECU 3 determines that the engine 2 is in the automatic stop state, the ECU 3 executes the process of step S2. If the ECU 3 determines that the engine 2 is not in the automatic stop state, the ECU 3 may repeat the process of step S1.
In step S2, the ECU 3 keeps the solenoid valve 16 open when the engine 2 is in an automatic stop state. As a result, the gaseous fuel in the first fuel tank 41 can be guided to the fuel switching device 5, and the gaseous fuel can be immediately supplied to the engine 2 when the engine 2 is started. The startability of the engine 2 can be maintained.

In step S3, the ECU 3 determines whether restart conditions for the engine 2 are satisfied.

For example, the ECU 3 may determine that the restart/stop condition for the engine 2 is satisfied when the driver depresses the accelerator pedal 112.

In an AT vehicle, a CVT vehicle, an AMT vehicle, or a DCT vehicle, the ECU 3 may determine that the restart condition for the engine 2 is satisfied when the brake pedal 114 is released by the driver.

In a manual transmission vehicle, the ECU 3 may determine that the restart condition for the engine 2 is satisfied when the clutch is released by the driver.

The ECU 3 may determine that the restart condition for the engine 2 is satisfied when the vehicle speed becomes equal to or higher than a predetermined speed.

The ECU 3 may determine that the conditions for restarting the engine 2 are satisfied when a predetermined period of time has passed since the engine 2 entered the automatic stop state.

The ECU 3 may determine that the restart condition for the engine 2 is satisfied when the battery voltage becomes equal to or lower than a predetermined value.

The ECU 3 may determine that the restart condition for the engine 2 is satisfied when the total amount of electrical load is equal to or greater than a predetermined value.

The ECU 3 may determine that the restart condition for the engine 2 is satisfied when the air conditioner provided in the vehicle 1 is activated.

The ECU 3 may determine that the restart condition for the engine 2 is satisfied when the IS prohibition switch is operated.

The ECU 3 may determine that the restart condition for the engine 2 is satisfied when the gear is shifted from "D" to "P", "R", or "M" by the driver.

When the ECU 3 determines that the restart condition for the engine 2 is satisfied, the ECU 3 executes the process of step S4. If the ECU 3 determines that the restart condition for the engine 2 is not satisfied, the ECU 3 repeats the process of step S3.

In step S4, the ECU 3 determines whether the rotation speed (ENGrpm) of the engine 2 is 0 or not.

When the ECU 3 determines that the rotation speed (ENGrpm) of the engine 2 is 0, it performs the process of step S6. When the ECU 3 determines that the rotation speed (ENGrpm) of the engine 2 is not 0, that is, the rotation speed (ENGrpm) of the engine 2 is greater than 0, it performs the process of step S5.

In step S5, the ECU 3 selects gaseous fuel. Thereby, gaseous fuel is supplied to the intake manifold 6 in step S10, and then the engine 2 is started using the gaseous fuel.

In step S6, the ECU 3 determines whether the speed (vehicle speed) V of the vehicle 1 is zero.

When the ECU 3 determines that the vehicle speed V is 0, it performs the process of step S7. When the ECU 3 determines that the vehicle speed V is not 0, that is, the vehicle speed V is greater than 0, it performs the process of step S8.

In step S7, the ECU 3 selects liquid fuel. As a result, in step S10, liquid fuel is supplied to the intake manifold 6, and then the engine 2 is started using the liquid fuel.

In step S8, the ECU 3 determines whether a predetermined time has elapsed since starting the fuel cut (F/C) in which fuel is not supplied to the engine 2.

Here, the predetermined time is, for example, the time during which a predetermined amount or more of fuel remains in the intake manifold 6 at which the engine 2 can be started. By executing the fuel cut, no fuel is injected into the intake manifold 6, so the fuel in the intake manifold 6 gradually decreases. The predetermined time is a standard for determining the amount of fuel remaining in the intake manifold 6.

If the ECU 3 determines that a predetermined time has elapsed since the start of the fuel cut, there is no fuel remaining in the intake manifold 6, so the ECU 3 performs the process of step S7. If the ECU 3 determines that the predetermined time has not elapsed since the start of the fuel cut, fuel remains in the intake manifold 6, so it performs the process of step S9.

Note that if the fuel cut has not been executed, the ECU 3 determines that a predetermined time has not elapsed since the fuel cut was started, and performs the process of step S9.

In step S9, similarly to step S5, the ECU 3 selects gaseous fuel. Thereby, gaseous fuel is supplied to the intake manifold 6 in step S10, and then the engine 2 is started using the gaseous fuel.

Note that the driver can also forcefully switch to a desired fuel using the fuel selection switch 14.

The ECU 3 according to the present embodiment is configured to operate the ECU 3 according to the present embodiment when the restart condition of the engine 2 is satisfied (for example, in the case of Yes in step S3 in FIG. 2), and if the engine 2 is rotating (for example, in the case of step S4 in FIG. 2). If Yes), gaseous fuel is selected as the fuel supplied to the engine 2; otherwise (i.e., when the engine 2 is not rotating), the liquid fuel is selected as the fuel supplied to the engine 2. It's okay.

According to this configuration, if the rotation speed (ENGrpm) of the engine 2 is not 0 before restarting the engine 2, it is determined that the engine 2 is rotating due to inertia and is therefore in a state where the engine is likely to completely explode. It is possible to restart the engine by making a judgment and selecting a gaseous fuel that prioritizes fuel efficiency. On the other hand, before restarting engine 2,
If the engine 2 is not rotating, it is determined that the engine 2 is in a state where complete explosion is difficult to occur, and a liquid fuel that prioritizes startability can be selected and restarted.

In addition, the ECU 3 according to the present embodiment is configured to operate when the restart condition of the engine 2 is satisfied (for example, in the case of Yes in step S3 in FIG. 2) and when the engine is not rotating (for example, in the case of step S3 in FIG. 2). If the speed of the vehicle 1 (vehicle speed V) is not 0 (for example, the case of No in step S6 in FIG. 2), even if gaseous fuel is selected as the fuel to be supplied to the engine 2. good.

According to this configuration, even if the rotation speed (ENGrpm) of the engine 2 is not 0 before restarting the engine 2, if the vehicle speed is V, the vehicle 1 is coasting, and there is no delay after the engine 2 is stopped. It is possible to determine that the engine 2 is in a warmed-up state without any problem, select gaseous fuel that prioritizes fuel efficiency, and restart the engine.

Further, the ECU 3 according to the present embodiment operates when the restart condition of the engine 2 is satisfied (for example, in the case of Yes in step S3 in FIG. 2) and when the engine 2 is not rotating (for example, in the case of Yes in step S3 in FIG. 2). If the vehicle speed (vehicle speed V) is not 0 (for example, No in step S6 in FIG. 2), and within a predetermined time after the fuel cut is started ( For example, in the case of No in step S8 in FIG. 2), gaseous fuel is selected as the fuel to be supplied to the engine 2, and if a predetermined time has elapsed since the fuel cut was started (for example, in the case of step S8 in FIG. In the case of Yes in S8), liquid fuel may be selected as the fuel supplied to the engine 2.

According to this configuration, if a predetermined period of time has not elapsed since the fuel supply was stopped (fuel cut), it is determined that there is a high possibility that unburned fuel is deposited from the fuel supply source to the combustion chamber of the engine 2. gaseous fuel can be selected for restart. On the other hand, if a predetermined period of time has passed since the fuel supply was stopped (fuel cut), it is determined that there is a low possibility that unburned fuel is deposited from the fuel supply source to the combustion chamber, and liquid fuel is used. The engine 2 can be restarted reliably.

(3) Timing chart Next, the operation of the ECU 3 according to this embodiment will be explained using FIG. FIG. 3 is a timing chart for explaining this operation.

At time t1, the EMC 3 selects gaseous fuel as the fuel to be supplied to the engine 2 because the vehicle speed V is not 0 (V>0) and the rotation speed (ENGrpm) of the engine 2 is not 0.

At time t2, the EMC 3 selects liquid fuel as the fuel to be supplied to the engine 2 because the vehicle speed V is 0 (V=0) and the rotation speed (ENGrpm) of the engine 2 is not 0.

At time t3, the EMC 3 supplies fuel to the engine 2 because the vehicle speed V is not 0 (V>0), the rotation speed (ENGrpm) of the engine 2 is 0, and the predetermined time has passed since the start of fuel cut. Gaseous fuel is selected as the fuel to be used.

At time t4, the EMC 3 determines that the vehicle speed V is not 0 (V>0), the rotation speed (ENGrpm) of the engine 2 is 0, and a predetermined time has elapsed since the fuel cut was started, so the EMC 3 Select liquid fuel as the fuel supplied to the

Although the present invention has been described in detail using the embodiments described above, it will be apparent to those skilled in the art that the present invention is not limited to the embodiments described herein. The present invention can be implemented as modifications and variations without departing from the spirit and scope of the present invention as defined by the claims. Therefore, the description in this specification is for the purpose of illustrative explanation and does not have any limiting meaning on the present invention.

According to the present embodiment, it is possible to provide a fuel supply device that can improve fuel efficiency while ensuring engine startability.

1... Vehicle system 2... Engine 3... ECU
4... Fuel tank 5... Fuel switching device 6... Intake manifold 7... Starter 8... Drive wheel 9... Clutch 10... Transmission 11... Pedal 12... Water temperature sensor 13... Vehicle speed sensor 14... Fuel selection switch 15... Injector 16... Solenoid valve 20...IS prohibition switch 41...First fuel tank 42...Second fuel tank 112...Accelerator pedal 114...Brake pedal 116...Clutch pedal

Claims (1)

A fuel supply device capable of supplying liquid fuel and gaseous fuel to an engine installed in a vehicle,
comprising a control unit that automatically stops the engine based on an automatic stop condition and restarts the engine based on a restart condition,
When the restart condition is satisfied, when the engine is not rotating, and when the speed of the vehicle is not 0, the control unit:
Selecting the gaseous fuel as the fuel to be supplied to the engine if it is within a predetermined time after a fuel cut in which fuel is not supplied to the engine is started;
The fuel supply device is characterized in that if the predetermined time has elapsed since the start of the fuel cut, the liquid fuel is selected as the fuel to be supplied to the engine .

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