Engine system

Abstract

To provide an engine system capable of improving calculation accuracy of a fuel consumption amount of a vehicle.SOLUTION: An engine system 1 includes: an injection amount determination section 31 that determines an injection amount of gas fuel from an injector 12; an injection control section 32 that controls the injector 12 so as to inject gas fuel in accordance with the determined injection amount; a pressure sensor 20 that detects pressure of the gas fuel upstream of the injector 12; a pressure change amount calculation section 33 that calculates change amounts (pressure change amounts) of pressure of the gas fuel detected by the pressure sensor 20 before the gas fuel is injected from the injector 12 and pressure of the gas fuel detected by the pressure sensor 20 after the gas fuel is injected from the injector 12; a fuel consumption amount correction section 34 that corrects a fuel consumption amount corresponding to the determined injection amount in accordance with the pressure change amount; and a consumption amount integration section 35 that integrates the corrected fuel consumption amount.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to an engine system. [Background technology]

[0002] In recent years, it has become commonplace to have a function for monitoring fuel consumption to indicate engine performance during certification testing, etc. For example, Patent Document 1 describes a technology that integrates the amount of fuel injected into the injector of a gas engine, estimates the amount of fuel consumed in the fuel tank from the pressure and temperature in the fuel tank, and detects whether or not there is an abnormality in the fuel system based on the integrated value of the amount of fuel injected and the amount of fuel consumed. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 8-93564 Summary of the Invention [Problem to be solved by the invention]

[0004] For example, in industrial vehicles where engine loads change suddenly frequently, the use of gaseous fuel as in the above-mentioned conventional technology has the following problems, unlike the use of liquid fuel. That is, in industrial vehicles, after the fuel injection amount is calculated, there are many situations where the fuel pressure and temperature are likely to change before the fuel is injected from the injector, and the actual fuel injection amount from the injector is likely to differ from the calculated fuel injection amount. As a result, the integrated fuel consumption amount differs from the actual fuel consumption amount.

[0005] An object of the present invention is to provide an engine system that can improve the accuracy of calculating the fuel consumption of a vehicle. [Means for solving the problem]

[0006] One aspect of the present invention is an engine system mounted on a vehicle, comprising an engine, an air supply unit that supplies air to the engine, a fuel supply unit having an injector that injects gaseous fuel toward the engine, an injection amount determination unit that determines the amount of gaseous fuel injected from the injector, an injection control unit that controls the injector to inject gaseous fuel according to the injection amount determined by the injection amount determination unit, a state detection unit that detects information regarding the state of the engine, a state change amount calculation unit that calculates the amount of change between information regarding the engine state detected by the state detection unit before the gaseous fuel is injected from the injector and information regarding the engine state detected by the state detection unit after the gaseous fuel is injected from the injector, a consumption amount correction unit that corrects the fuel consumption equivalent to the injection amount determined by the injection amount determination unit according to the amount of change calculated by the state change amount calculation unit, and a consumption amount accumulation unit that accumulates the fuel consumption corrected by the consumption amount correction unit.

[0007] In such an engine system, the amount of change between information about the engine state before the gaseous fuel is injected from the injector and information about the engine state after the gaseous fuel is injected from the injector is calculated. Then, the fuel consumption amount corresponding to the injection amount of the gaseous fuel is corrected according to the amount of change in the information about the engine state, and the corrected fuel consumption amount is integrated. By correcting the fuel consumption amount in this manner, the difference between the integrated value of the fuel consumption amount and the actual fuel consumption amount is reduced even in a situation in which the engine state is likely to change between the time when the injection amount of the gaseous fuel is determined and the time when the gaseous fuel is actually injected from the injector. This improves the calculation accuracy of the vehicle's fuel consumption amount.

[0008] The state change amount calculation unit may calculate an amount of change between the information on the engine state detected by the state detection unit after the injection amount is determined by the injection amount determination unit and before the gaseous fuel is injected from the injector, and the information on the engine state detected by the state detection unit after the gaseous fuel is injected from the injector. In this configuration, in a situation in which the engine state is likely to change between the time the injection amount of the gaseous fuel is determined and the time the gaseous fuel is actually injected from the injector, the deviation between the integrated value of the fuel consumption amount and the actual value of the fuel consumption amount is further reduced.

[0009] The state detection unit may detect the pressure or temperature of the gaseous fuel upstream of the injector as information on the state of the engine. In this configuration, the amount of change between the pressure or temperature of the gaseous fuel before the gaseous fuel is injected from the injector and the pressure or temperature of the gaseous fuel after the gaseous fuel is injected from the injector is calculated. Then, the fuel consumption amount corresponding to the injection amount of the gaseous fuel is corrected according to the amount of change in the pressure or temperature of the gaseous fuel. Therefore, even under a situation in which the pressure and temperature of the gaseous fuel are likely to change between the time when the injection amount of the gaseous fuel is determined and the time when the gaseous fuel is actually injected from the injector, the difference between the integrated value of the fuel consumption amount and the actual value of the fuel consumption amount is reduced.

[0010] The state detection unit may detect the pressure or temperature of air supplied to the engine as information on the state of the engine. In such a configuration, the amount of change between the air pressure or temperature before the gaseous fuel is injected from the injector and the air pressure or temperature after the gaseous fuel is injected from the injector is calculated. Then, the fuel consumption amount corresponding to the injection amount of the gaseous fuel is corrected according to the amount of change in the air pressure or temperature. Therefore, even under a situation in which the air pressure and temperature are likely to change between the time when the injection amount of the gaseous fuel is determined and the time when the gaseous fuel is actually injected from the injector, the difference between the integrated value of the fuel consumption amount and the actual value of the fuel consumption amount is reduced.

[0011] The state detection unit may detect the opening of the accelerator of the vehicle as the information on the engine state. In this configuration, the amount of change between the opening of the accelerator before the gaseous fuel is injected from the injector and the opening of the accelerator after the gaseous fuel is injected from the injector is calculated. Then, the fuel consumption amount corresponding to the injection amount of the gaseous fuel is corrected according to the amount of change in the opening of the accelerator. Therefore, even under a situation in which the engine load is likely to change between the time when the injection amount of the gaseous fuel is determined and the time when the gaseous fuel is actually injected from the injector, the difference between the integrated value of the fuel consumption amount and the actual value of the fuel consumption amount is reduced.

[0012] The state detection unit may detect the oil pressure of a hydraulic pump driven by the engine as information related to the state of the engine. In such a configuration, a change amount between the oil pressure of the hydraulic pump before the gas fuel is injected from the injector and the oil pressure of the hydraulic pump after the gas fuel is injected from the injector is calculated. Then, the fuel consumption amount corresponding to the injection amount of the gas fuel is corrected according to the change amount of the oil pressure of the hydraulic pump. Therefore, even under a situation where the load of the engine is likely to change between the time when the injection amount of the gas fuel is determined and the time when the gas fuel is actually injected from the injector, the difference between the integrated value of the fuel consumption amount and the actual value of the fuel consumption amount is reduced. Effect of the Invention

[0013] According to the present invention, it is possible to improve the accuracy of calculating the fuel consumption of a vehicle. [Brief description of the drawings]

[0014] [Figure 1] 1 is a schematic configuration diagram showing an engine system according to a first embodiment of the present invention. [Diagram 2] 2 is a block diagram showing a configuration of a control system of the engine system shown in FIG. 1. [Diagram 3] 3 is a flowchart showing a processing procedure executed by an ECU shown in FIG. 2. [Figure 4]2 is a timing diagram showing the relationship between the NE counter, the stroke of each cylinder, the calculation of the injection amount of each cylinder, the timing of fuel injection, and the detection of the sensor value in the engine shown in FIG. 1. [Diagram 5] FIG. 6 is a block diagram showing the configuration of a control system of an engine system according to a second embodiment of the present invention. [Figure 6] 6 is a flowchart showing a process executed by an ECU shown in FIG. 5. [Figure 7] FIG. 4 is a schematic configuration diagram showing an engine system according to a third embodiment of the present invention. [Figure 8] FIG. 8 is a block diagram showing a configuration of a control system of the engine system shown in FIG. [Figure 9] FIG. 11 is a block diagram showing the configuration of a control system of an engine system according to a fourth embodiment of the present invention. [Figure 10] FIG. 11 is a schematic configuration diagram showing an engine system according to a fifth embodiment of the present invention. [Figure 11] FIG. 11 is a block diagram showing the configuration of a control system of the engine system shown in FIG. [Figure 12] 12 is a flowchart showing a process executed by an ECU shown in FIG. 11. [Figure 13] FIG. 11 is a schematic configuration diagram showing an engine system according to a sixth embodiment of the present invention. [Figure 14] FIG. 14 is a block diagram showing the configuration of a control system of the engine system shown in FIG. [Figure 15] 15 is a flowchart showing a process executed by the ECU shown in FIG. 14. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. In the drawings, the same or equivalent elements are designated by the same reference numerals, and duplicated explanations will be omitted.

[0016] Fig. 1 is a schematic diagram showing an engine system according to a first embodiment of the present invention. In Fig. 1, an engine system 1 of this embodiment is mounted on a vehicle 2. The vehicle 2 is, for example, an industrial vehicle such as a forklift. The engine system 1 uses LPG (Liquefied Petroleum Gas) as fuel. LPG is a liquefied petroleum gas whose main components are propane and butane.

[0017] The engine system 1 includes an engine 3, an intake pipe 4, an air cleaner 5, a throttle valve 6, an LPG cylinder 7, a fuel pipe 8, a regulator 9, a fuel pipe 10, a distribution pipe 11, four injectors 12, and a hydraulic pump 13.

[0018] The engine 3 is, for example, a four-cylinder engine having four cylinders. The engine 3 performs four strokes, namely, an intake stroke, a compression stroke, a combustion stroke, and an exhaust stroke, as one cycle for each cylinder (see FIG. 4). The four cylinders are arranged in a line in one direction and are referred to as the first cylinder, the second cylinder, the third cylinder, and the fourth cylinder, respectively. The engine 3 performs the four strokes in the order of the first cylinder, the third cylinder, the fourth cylinder, and the second cylinder.

[0019] The intake pipe 4 is connected to the engine 3 via an intake manifold 14. The intake pipe 4 is a flow path through which air (intake air) supplied to the engine 3 flows. The air cleaner 5 is disposed midway through the intake pipe 4. The air cleaner 5 removes foreign matter such as dust and dirt contained in the intake air. The throttle valve 6 is disposed in the intake pipe 4 between the air cleaner 5 and the intake manifold 14. The throttle valve 6 is an electromagnetic flow control valve that controls the flow rate of the intake air.

[0020] The intake pipe 4 , the air cleaner 5 , the throttle valve 6 and the intake manifold 14 constitute an air supply unit 15 that supplies air to the engine 3 .

[0021] The LPG cylinder 7 is a fuel cylinder that is filled with LPG, which is a fuel, in a liquid state. The fuel pipe 8 connects the LPG cylinder 7 and a regulator 9. The fuel pipe 8 is a flow path through which liquid fuel flows from the LPG cylinder 7 to the regulator 9.

[0022] The regulator 9 is a pressure reducing valve that reduces the pressure of the liquid fuel in the LPG cylinder 7 to vaporize it. The fuel pipe 10 connects the regulator 9 to a distribution pipe 11. The fuel pipe 10 is a flow path through which gaseous fuel (fuel gas) flows from the regulator 9 to the distribution pipe 11. The distribution pipe 11 distributes the gaseous fuel to each injector 12.

[0023] The injectors 12 are attached to the distribution pipe 11 so as to be disposed at equal intervals along the axial direction of the distribution pipe 11. The injectors 12 are electromagnetic fuel injection valves that intermittently inject fuel gas into the engine 3. The injectors 12 may inject the fuel gas into the intake manifold 14, or may inject the fuel gas directly into the engine 3.

[0024] The LPG cylinder 7 , the fuel pipe 8 , the regulator 9 , the fuel pipe 10 , the distribution pipe 11 and the injectors 12 constitute a fuel supply unit 16 that supplies fuel to the engine 3 .

[0025] The hydraulic pump 13 is driven by the engine 3. The hydraulic pump 13 discharges hydraulic oil to be supplied to a hydraulic actuator (not shown) such as a lift cylinder mounted on the vehicle 2.

[0026] As shown in FIG. 2, the engine system 1 also includes an accelerator sensor 18, a rotation speed sensor 19, a pressure sensor 20, a map memory 21, a display 22, and an ECU (Electronic Control Unit) 23.

[0027] The accelerator sensor 18 is a sensor that detects the opening degree (accelerator opening degree) of an accelerator 24 of the vehicle 2. The rotation speed sensor 19 is a sensor that detects the rotation speed of the engine 3 (engine rotation speed).

[0028] The pressure sensor 20 is a sensor that detects the pressure of the gaseous fuel upstream of the injector 12. The pressure sensor 20 detects, for example, the pressure inside the distribution pipe 11. The pressure sensor 20 constitutes a state detection unit that detects information related to the state of the engine 3.

[0029] Correction map data is stored in the map memory 21. The correction map data is map data that represents a relationship between a pressure change amount of the gaseous fuel before and after the gaseous fuel is injected from the injector 12 and a correction amount of the fuel consumption amount. The correction map data is defined in advance by an experiment, a simulation, or the like.

[0030] The display 22 is disposed at the driver's seat of the vehicle 2. The display 22 displays the available driving distance of the vehicle 2 by using numbers, a meter, or the like. The available driving distance is the distance that the vehicle 2 can travel with the remaining amount of fuel.

[0031] The ECU 23 is composed of a CPU, a RAM, a ROM, an input / output interface, etc. The ECU 23 executes predetermined processing based on the detection values ​​of the accelerator sensor 18, the rotation speed sensor 19, and the pressure sensor 20 and the correction map data stored in the map memory 21, and controls the injector 12 and the display 22.

[0032] As shown in FIG. 2, the ECU 23 has an injection amount determination unit 31, an injection control unit 32, a pressure change amount calculation unit 33, a fuel consumption amount correction unit 34, a consumption amount integration unit 35, and a cruising distance calculation unit 36.

[0033] The injection amount determination unit 31 determines the injection amount of gaseous fuel from the injector 12 based on the accelerator opening detected by the accelerator sensor 18 and the engine speed detected by the engine speed sensor 19 .

[0034] The injection control unit 32 controls the injector 12 so as to inject the gas fuel according to the injection amount determined by the injection amount determination unit 31 .

[0035] The pressure change amount calculation unit 33 calculates the amount of change (pressure change amount) between the pressure of the gas fuel upstream of the injector 12 detected by the pressure sensor 20 before the gas fuel is injected from the injector 12 after the injection amount has been determined by the injection amount determination unit 31, and the pressure of the gas fuel upstream of the injector 12 detected by the pressure sensor 20 after the gas fuel is injected from the injector 12.

[0036] The pressure change amount calculation unit 33 constitutes a state change amount calculation unit that calculates the amount of change between information regarding the state of the engine 3 detected by the pressure sensor 20 before the gas fuel is injected from the injector 12 and information regarding the state of the engine 3 detected by the pressure sensor 20 after the gas fuel is injected from the injector 12.

[0037] The fuel consumption correction unit 34 corrects the fuel consumption equivalent to the injection amount determined by the injection amount determination unit 31 in accordance with the pressure change calculated by the pressure change calculation unit 33. The fuel consumption correction unit 34 corrects the fuel consumption equivalent to the injection amount by using the correction map data stored in the map memory 21. The fuel consumption correction unit 34 cooperates with the map memory 21 to constitute a consumption correction unit that corrects the fuel consumption equivalent to the injection amount of gaseous fuel in accordance with the pressure change.

[0038] The fuel consumption integrating unit 35 integrates the fuel consumption corrected by the fuel consumption correcting unit 34 to calculate an integrated fuel consumption value.

[0039] The cruising distance calculation unit 36 ​​calculates the remaining cruising distance of the vehicle 2 based on the accumulated fuel consumption value calculated by the consumption amount accumulation unit 35, and causes the display 22 to display the remaining cruising distance.

[0040] 3 is a flowchart showing a procedure of a process executed by the ECU 23. This process is executed when an ignition switch (not shown) is turned on.

[0041] 3, the ECU 23 first acquires the detection values ​​of the accelerator sensor 18 and the rotation speed sensor 19 (step S101). Then, the ECU 23 calculates an injection amount command value of the gas fuel from the injector 12 based on the detection values ​​of the accelerator sensor 18 and the rotation speed sensor 19 (step S102).

[0042] Next, the ECU 23 acquires a detection value of the pressure sensor 20 (step S103). Next, the ECU 23 controls the injector 12 to inject gaseous fuel according to the injection amount command value calculated in step S102 (step S104). At this time, the ECU 23 outputs a drive signal according to the injection amount command value to the injector 12.

[0043] Next, the ECU 23 again acquires the detection value of the pressure sensor 20 (step S105). Then, the ECU 23 calculates the difference between the detection value of the pressure sensor 20 acquired in step S103 and the detection value of the pressure sensor 20 acquired in step S105 as the pressure change amount (step S106).

[0044] Next, the ECU 23 corrects the fuel consumption amount corresponding to the injection amount command value calculated in step S102 by using the correction map data stored in the map memory 21 (step S107). Specifically, the ECU 23 obtains a correction amount corresponding to the pressure change amount from the correction map data, and corrects the fuel consumption amount by using the correction amount.

[0045] Next, the ECU 23 calculates a new integrated fuel consumption value by adding the fuel consumption corrected in step S107 to the current integrated fuel consumption value (step S108). Next, the ECU 23 calculates the cruising distance of the vehicle 2 based on the integrated fuel consumption value calculated in step S108 (step S109). Then, the ECU 23 causes the display 22 to display the cruising distance (step S110).

[0046] Here, the injection amount determination unit 31 executes steps S101 and S102. The injection control unit 32 executes step S104. The pressure change amount calculation unit 33 executes steps S103, S105, and S106. The fuel consumption correction unit 34 executes step S107. The consumption integration unit 35 executes step S108. The cruising range calculation unit 36 ​​executes steps S109 and S110.

[0047] In the engine system 1 as described above, as shown in Fig. 4, after the NE counter is reset, the injection amount of the first cylinder of the engine 3 is calculated. The NE counter is a sensor that measures the angle of the crankshaft (not shown) of the engine 3. The crankshaft rotates twice in one cycle. After that, gaseous fuel is injected from the injector 12 of the first cylinder immediately before the intake stroke of the first cylinder.

[0048] Next, after the NE counter is reset, the injection amount for the third cylinder of the engine 3 is calculated. Then, gaseous fuel is injected from the injector 12 for the third cylinder immediately before the intake stroke of the third cylinder.

[0049] Next, after the NE counter is reset, the injection amount for the fourth cylinder of the engine 3 is calculated. Then, gaseous fuel is injected from the injector 12 for the fourth cylinder immediately before the intake stroke of the fourth cylinder.

[0050] Next, after the NE counter is reset, the injection amount of the second cylinder of the engine 3 is calculated. Then, immediately before the intake stroke of the second cylinder, gaseous fuel is injected from the injector 12 of the second cylinder. Then, in the first cylinder of the engine 3, the calculation of the injection amount and the injection of gaseous fuel from the injector 12 are performed again.

[0051] By the way, the time t from the calculation of the injection amount of the first cylinder to the start of injection of the gaseous fuel from the injector 12 of the first cylinder is longer than the time t0 from the injection of the gaseous fuel from the injector 12 of the second cylinder to the calculation of the injection amount of the first cylinder. The same is true for the third cylinder, the fourth cylinder, and the second cylinder.

[0052] In industrial vehicles such as forklifts, the engine load often changes suddenly, so if the time t from when the injection amount is calculated to when the injection of the gaseous fuel from the injector 12 starts is long, the pressure and temperature of the gaseous fuel are likely to change during that time. If the pressure and temperature of the gaseous fuel change before the gaseous fuel is injected from the injector 12, the actual injection amount from the injector 12 deviates from the injection amount command value, and the integrated fuel consumption amount differs from the actual fuel consumption amount. As a result, the calculation accuracy of the cruising distance of the vehicle 2 decreases.

[0053] To address this issue, the pressure sensor 20 detects the pressure of the gaseous fuel upstream of the injector 12 before and after the gaseous fuel is injected from the injector 12 of the first cylinder. Then, the amount of change in pressure of the gaseous fuel is calculated, and the fuel consumption amount corresponding to the injection amount in the first cylinder is corrected according to the amount of change in pressure. The correction of the fuel consumption amount is performed, for example, until the next calculation of the injection amount for the first cylinder. The same applies to the third, fourth, and second cylinders.

[0054] The fuel consumption amount corrected for each cylinder is thus accumulated to calculate an accumulated fuel consumption amount value, and the cruising distance of the vehicle 2 is then calculated based on the accumulated fuel consumption amount value.

[0055] As described above, in this embodiment, the amount of change between the information on the state of the engine 3 before the gaseous fuel is injected from the injector 12 and the information on the state of the engine 3 after the gaseous fuel is injected from the injector 12 is calculated. Then, the fuel consumption amount corresponding to the injection amount of the gaseous fuel is corrected according to the amount of change in the information on the state of the engine 3, and the corrected fuel consumption amount is integrated. By correcting the fuel consumption amount in this manner, even under a situation in which the state of the engine 3 is likely to change between the time when the injection amount of the gaseous fuel is determined and the time when the gaseous fuel is actually injected from the injector 12, the difference between the integrated value of the fuel consumption amount and the actual fuel consumption amount is reduced. This improves the calculation accuracy of the fuel consumption amount of the vehicle 2. As a result, the calculation accuracy of the cruising distance of the vehicle 2 can be improved.

[0056] Furthermore, in this embodiment, a change amount is calculated between information on the state of the engine 3 after the injection amount of gaseous fuel is determined and before the gaseous fuel is injected from the injector 12, and information on the state of the engine 3 after the gaseous fuel is injected from the injector 12. Therefore, in a situation in which the state of the engine 3 is likely to change between the time when the injection amount of gaseous fuel is determined and the time when the gaseous fuel is actually injected from the injector 12, the difference between the integrated value of the fuel consumption amount and the actual value of the fuel consumption amount is further reduced.

[0057] In this embodiment, the amount of change (pressure change amount) between the pressure of the gaseous fuel before the gaseous fuel is injected from the injector 12 and the pressure of the gaseous fuel after the gaseous fuel is injected from the injector 12 is calculated. Then, the fuel consumption amount corresponding to the injection amount of the gaseous fuel is corrected according to the amount of change in pressure of the gaseous fuel. Therefore, even under a situation in which the pressure of the gaseous fuel is likely to change after the injection amount of the gaseous fuel is determined and before the gaseous fuel is injected from the injector 12, the difference between the integrated value of the fuel consumption amount and the actual value of the fuel consumption amount is reduced.

[0058] Fig. 5 is a block diagram showing the configuration of a control system of an engine system according to a second embodiment of the present invention. In Fig. 5, an engine system 1A of this embodiment includes the accelerator sensor 18, the rotation speed sensor 19, a temperature sensor 40, a map memory 21A, the display 22, and an ECU 23A.

[0059] The temperature sensor 40 is a sensor that detects the temperature of the gas fuel upstream of the injector 12. The temperature sensor 40 detects the temperature inside the distribution pipe 11 (see FIG. 1), for example. The temperature sensor 40 constitutes a state detection unit that detects information related to the state of the engine 3.

[0060] The map memory 21A stores correction map data that indicates the relationship between the amount of change in temperature of the gaseous fuel before and after the gaseous fuel is injected from the injector 12 and the amount of correction for the amount of fuel consumption.

[0061] The ECU 23A has a temperature change amount calculation section 33A and a fuel consumption amount correction section 34A, instead of the pressure change amount calculation section 33 and the fuel consumption amount correction section 34 in the first embodiment.

[0062] The temperature change calculation unit 33A calculates the amount of change (temperature change) between the temperature of the gaseous fuel upstream of the injector 12 detected by the temperature sensor 40 before the gaseous fuel is injected from the injector 12 after the injection amount has been determined by the injection amount determination unit 31, and the temperature of the gaseous fuel upstream of the injector 12 detected by the temperature sensor 40 after the gaseous fuel has been injected from the injector 12.

[0063] The temperature change amount calculation unit 33A constitutes a state change amount calculation unit that calculates the amount of change between information regarding the state of the engine 3 detected by the temperature sensor 40 before the gas fuel is injected from the injector 12 and information regarding the state of the engine 3 detected by the temperature sensor 40 after the gas fuel is injected from the injector 12.

[0064] The fuel consumption correction unit 34A corrects the fuel consumption equivalent to the injection amount determined by the injection amount determination unit 31 in accordance with the temperature change calculated by the temperature change calculation unit 33A. The fuel consumption correction unit 34A corrects the fuel consumption equivalent to the injection amount by using the correction map data stored in the map memory 21A. The fuel consumption correction unit 34A cooperates with the map memory 21A to constitute a consumption correction unit that corrects the fuel consumption equivalent to the injection amount of gaseous fuel in accordance with the temperature change.

[0065] Fig. 6 is a flowchart showing a process executed by the ECU 23A, and corresponds to Fig. 3. In Fig. 6, after executing the above steps S101 and S102, the ECU 23A acquires a detection value of the temperature sensor 40 (step S103A). Then, the ECU 23A executes the above step S104.

[0066] Next, the ECU 23A again acquires the detection value of the temperature sensor 40 (step S105A). Then, the ECU 23A calculates the difference between the detection value of the temperature sensor 40 acquired in step S103A and the detection value of the temperature sensor 40 acquired in step S105A as the amount of temperature change (step S106A).

[0067] Next, the ECU 23A corrects the fuel consumption amount corresponding to the injection amount command value calculated in step S102 by using the correction map data stored in the map memory 21A (step S107A). Specifically, the ECU 23A obtains a correction amount corresponding to the temperature change amount from the correction map data, and corrects the fuel consumption amount by using the correction amount. After that, the ECU 23A executes the above steps S108 to S110.

[0068] Here, temperature change amount calculation section 33A executes steps S103A, S105A, and S106A. Fuel consumption correction section 34A executes step S107A.

[0069] In this embodiment, the amount of change (amount of temperature change) between the temperature of the gaseous fuel before the gaseous fuel is injected from the injector 12 and the temperature of the gaseous fuel after the gaseous fuel is injected from the injector 12 is calculated. Then, the amount of fuel consumption corresponding to the injection amount of the gaseous fuel is corrected according to the amount of change in the temperature of the gaseous fuel. Therefore, even under a situation in which the temperature of the gaseous fuel is likely to change between the time when the injection amount of the gaseous fuel is determined and the time when the gaseous fuel is actually injected from the injector 12, the difference between the integrated value of the fuel consumption amount and the actual value of the fuel consumption amount is reduced.

[0070] Fig. 7 is a schematic diagram showing an engine system according to a third embodiment of the present invention. Fig. 8 is a block diagram showing a configuration of a control system of the engine system shown in Fig. 7. In Fig. 7 and Fig. 8, the engine system 1B of this embodiment includes the accelerator sensor 18, the rotation speed sensor 19, the intake pressure sensor 45, the map memory 21B, the display 22, and the ECU 23B.

[0071] The intake pressure sensor 45 is a sensor that detects the pressure (intake pressure) of air supplied to the engine 3. The intake pressure sensor detects, for example, the pressure inside the intake manifold 14. The intake pressure sensor 45 constitutes a state detection unit that detects information related to the state of the engine 3.

[0072] The map memory 21B stores correction map data that indicates the relationship between the amount of change in intake air pressure (amount of pressure change) before and after the gas fuel is injected from the injector 12 and the amount of correction for the amount of fuel consumption.

[0073] The ECU 23B has a pressure change amount calculation section 33B and a fuel consumption amount correction section 34B, instead of the pressure change amount calculation section 33 and the fuel consumption amount correction section 34 in the first embodiment.

[0074] The pressure change amount calculation unit 33B calculates the amount of change (pressure change amount) between the intake pressure detected by the intake pressure sensor 45 before the gas fuel is injected from the injector 12 after the injection amount is determined by the injection amount determination unit 31, and the intake pressure detected by the intake pressure sensor 45 after the gas fuel is injected from the injector 12.

[0075] The pressure change amount calculation unit 33B constitutes a state change amount calculation unit that calculates the amount of change between information regarding the state of the engine 3 detected by the intake pressure sensor 45 before the gas fuel is injected from the injector 12 and information regarding the state of the engine 3 detected by the intake pressure sensor 45 after the gas fuel is injected from the injector 12.

[0076] The fuel consumption correction unit 34B corrects the fuel consumption equivalent to the injection amount determined by the injection amount determination unit 31 according to the pressure change calculated by the pressure change calculation unit 33B. The fuel consumption correction unit 34B corrects the fuel consumption equivalent to the injection amount by using the correction map data stored in the map memory 21B. The fuel consumption correction unit 34B cooperates with the map memory 21B to constitute a consumption correction unit that corrects the fuel consumption equivalent to the injection amount of gaseous fuel according to the pressure change.

[0077] The processing procedure of the ECU 23B is the same as that shown in FIG. 3 except that the detection value of the intake pressure sensor 45 and the correction map data stored in the map memory 21B are used, and therefore a description thereof will be omitted.

[0078] In this embodiment, the amount of change (pressure change amount) between the air pressure before the gaseous fuel is injected from the injector 12 and the air pressure after the gaseous fuel is injected from the injector 12 is calculated. Then, the fuel consumption amount corresponding to the injection amount of the gaseous fuel is corrected according to the amount of change in the air pressure. Therefore, even under a situation in which the air pressure is likely to change between the time when the injection amount of the gaseous fuel is determined and the time when the gaseous fuel is actually injected from the injector 12, the difference between the integrated value of the fuel consumption amount and the actual value of the fuel consumption amount is reduced.

[0079] Fig. 9 is a block diagram showing the configuration of a control system of an engine system according to a fourth embodiment of the present invention. In Fig. 9, an engine system 1C of this embodiment includes the accelerator sensor 18, the rotation speed sensor 19, an intake air temperature sensor 46, a map memory 21C, the display 22, and an ECU 23C.

[0080] The intake air temperature sensor 46 is a sensor that detects the temperature (intake air temperature) of air supplied to the engine 3. The intake air temperature sensor 46 detects, for example, the temperature inside the intake manifold 14. The intake air temperature sensor 46 constitutes a state detection unit that detects information related to the state of the engine 3.

[0081] The map memory 21C stores correction map data that indicates the relationship between the intake air temperature change amount (temperature change amount) before and after the gas fuel is injected from the injector 12 and the correction amount of the fuel consumption amount.

[0082] The ECU 23C has a temperature change amount calculation unit 33C and a fuel consumption amount correction unit 34C, instead of the pressure change amount calculation unit 33 and the fuel consumption amount correction unit 34 in the first embodiment.

[0083] The temperature change amount calculation unit 33C calculates the amount of change (temperature change amount) between the intake air temperature detected by the intake air temperature sensor 46 before the gas fuel is injected from the injector 12 after the injection amount has been determined by the injection amount determination unit 31, and the intake air temperature detected by the intake air temperature sensor 46 after the gas fuel has been injected from the injector 12.

[0084] The temperature change amount calculation unit 33C constitutes a state change amount calculation unit that calculates the amount of change between information regarding the state of the engine 3 detected by the intake air temperature sensor 46 before the gas fuel is injected from the injector 12 and information regarding the state of the engine 3 detected by the intake air temperature sensor 46 after the gas fuel is injected from the injector 12.

[0085] The fuel consumption correction unit 34C corrects the fuel consumption equivalent to the injection amount determined by the injection amount determination unit 31 in accordance with the temperature change calculated by the temperature change calculation unit 33C. The fuel consumption correction unit 34C corrects the fuel consumption equivalent to the injection amount by using the correction map data stored in the map memory 21C. The fuel consumption correction unit 34C cooperates with the map memory 21C to constitute a consumption correction unit that corrects the fuel consumption equivalent to the injection amount of gaseous fuel in accordance with the temperature change.

[0086] The processing procedure of the ECU 23C is similar to the procedure shown in FIG. 6 except that the detection value of the intake air temperature sensor 46 and the correction map data stored in the map memory 21C are used, and therefore a description thereof will be omitted.

[0087] In this embodiment, the amount of change (amount of temperature change) between the air temperature before the gaseous fuel is injected from the injector 12 and the air temperature after the gaseous fuel is injected from the injector 12 is calculated. Then, the amount of fuel consumption corresponding to the injection amount of the gaseous fuel is corrected according to the amount of change in the air temperature. Therefore, even under a situation in which the air temperature is likely to change between the time when the injection amount of the gaseous fuel is determined and the time when the gaseous fuel is actually injected from the injector 12, the difference between the integrated value of the fuel consumption and the actual value of the fuel consumption is reduced.

[0088] Fig. 10 is a schematic diagram showing an engine system according to a fifth embodiment of the present invention. Fig. 11 is a block diagram showing the configuration of a control system of the engine system shown in Fig. 10. In Fig. 10 and Fig. 11, an engine system 1D of this embodiment includes the accelerator sensor 18, the rotation speed sensor 19, a map memory 21D, the display 22, and an ECU 23D.

[0089] The engine system 1D does not include the above-mentioned pressure sensor 20, temperature sensor 40, intake pressure sensor 45, and intake temperature sensor 46. Here, the accelerator sensor 18 constitutes a state detection unit that detects information related to the state of the engine 3.

[0090] The map memory 21D stores correction map data that indicates the relationship between the amount of change in the accelerator opening before and after the gas fuel is injected from the injector 12 and the amount of correction for the fuel consumption.

[0091] The ECU 23D has an accelerator opening change amount calculation unit 33D and a fuel consumption amount correction unit 34D, instead of the pressure change amount calculation unit 33 and the fuel consumption amount correction unit 34 in the first embodiment.

[0092] The accelerator opening change amount calculation unit 33D calculates the amount of change (accelerator opening change amount) between the accelerator opening detected by the accelerator sensor 18 before the gas fuel is injected from the injector 12 after the injection amount has been determined by the injection amount determination unit 31 and the accelerator opening detected by the accelerator sensor 18 after the gas fuel has been injected from the injector 12.

[0093] The accelerator opening change amount calculation unit 33D constitutes a state change amount calculation unit that calculates the amount of change between information regarding the state of the engine 3 detected by the accelerator sensor 18 before the gas fuel is injected from the injector 12 and information regarding the state of the engine 3 detected by the accelerator sensor 18 after the gas fuel is injected from the injector 12.

[0094] The fuel consumption correction unit 34D corrects the fuel consumption equivalent to the injection amount determined by the injection amount determination unit 31 according to the accelerator opening change amount calculated by the accelerator opening change amount calculation unit 33D. The fuel consumption correction unit 34D corrects the fuel consumption equivalent to the injection amount by using the correction map data stored in the map memory 21D. The fuel consumption correction unit 34D cooperates with the map memory 21D to constitute a consumption correction unit that corrects the fuel consumption equivalent to the injection amount of gaseous fuel according to the accelerator opening change amount.

[0095] Fig. 12 is a flowchart showing the process executed by the ECU 23D, and corresponds to Fig. 3. In Fig. 12, after executing the above steps S101 and S102, the ECU 23D acquires the detection value of the accelerator sensor 18 (step S103D). Then, the ECU 23D executes the above step S104.

[0096] Next, the ECU 23D again acquires the detection value of the accelerator sensor 18 (step S105D). Then, the ECU 23D calculates the difference between the detection value of the accelerator sensor 18 acquired in step S103D and the detection value of the accelerator sensor 18 acquired in step S105D as the accelerator opening change amount (step S106D).

[0097] Next, the ECU 23D corrects the fuel consumption amount corresponding to the injection amount command value calculated in step S102 by using the correction map data stored in the map memory 21D (step S107D). Specifically, the ECU 23D obtains a correction amount corresponding to the accelerator opening change amount from the correction map data, and corrects the fuel consumption amount by using the correction amount. After that, the ECU 23D executes the above steps S108 to S110.

[0098] Here, the accelerator opening change amount calculation unit 33D executes steps S103D, S105D, and S106D. The fuel consumption correction unit 34D executes step S107D.

[0099] In this embodiment, the amount of change (accelerator opening change amount) between the accelerator opening before the gaseous fuel is injected from the injector 12 and the accelerator opening after the gaseous fuel is injected from the injector 12 is calculated. Then, the fuel consumption amount corresponding to the injection amount of the gaseous fuel is corrected according to the amount of change in the accelerator opening. Therefore, even under a situation in which the load of the engine 3 is likely to change between the time when the injection amount of the gaseous fuel is determined and the time when the gaseous fuel is actually injected from the injector 12, the difference between the integrated value of the fuel consumption amount and the actual value of the fuel consumption amount is reduced.

[0100] Fig. 13 is a schematic diagram showing an engine system according to a sixth embodiment of the present invention. Fig. 14 is a block diagram showing the configuration of a control system of the engine system shown in Fig. 13. In Fig. 13 and Fig. 14, an engine system 1E of this embodiment includes the accelerator sensor 18, the rotation speed sensor 19, the oil pressure sensor 50, a map memory 21E, the display 22, and an ECU 23E.

[0101] The hydraulic sensor 50 detects the hydraulic pressure of the hydraulic pump 13 driven by the engine 3. Specifically, the hydraulic sensor 50 detects the discharge pressure of the hydraulic pump 13. The hydraulic sensor 50 constitutes a state detection unit that detects information related to the state of the engine 3.

[0102] The map memory 21E stores correction map data that indicates the relationship between the amount of change in hydraulic pressure (amount of change in pressure) of the hydraulic pump 13 before and after the gas fuel is injected from the injector 12 and the amount of correction for the amount of fuel consumption.

[0103] The ECU 23E has a pressure change amount calculation unit 33E and a fuel consumption amount correction unit 34E, instead of the pressure change amount calculation unit 33 and the fuel consumption amount correction unit 34 in the first embodiment.

[0104] The pressure change amount calculation unit 33E calculates the amount of change (pressure change amount) between the oil pressure of the hydraulic pump 13 detected by the oil pressure sensor 50 before the gas fuel is injected from the injector 12 after the injection amount has been determined by the injection amount determination unit 31, and the oil pressure of the hydraulic pump 13 detected by the oil pressure sensor 50 after the gas fuel has been injected from the injector 12.

[0105] The pressure change amount calculation unit 33E constitutes a state change amount calculation unit that calculates the amount of change between information regarding the state of the engine 3 detected by the oil pressure sensor 50 before the gas fuel is injected from the injector 12 and information regarding the state of the engine 3 detected by the oil pressure sensor 50 after the gas fuel is injected from the injector 12.

[0106] The fuel consumption correction unit 34E corrects the fuel consumption equivalent to the injection amount determined by the injection amount determination unit 31 according to the pressure change calculated by the pressure change calculation unit 33E. The fuel consumption correction unit 34E corrects the fuel consumption equivalent to the injection amount by using the correction map data stored in the map memory 21E. The fuel consumption correction unit 34E cooperates with the map memory 21E to constitute a consumption correction unit that corrects the fuel consumption equivalent to the injection amount of gaseous fuel according to the pressure change.

[0107] Fig. 15 is a flowchart showing the process executed by the ECU 23E, and corresponds to Fig. 3. In Fig. 15, after executing the above steps S101 and S102, the ECU 23E acquires the detection value of the hydraulic sensor 50 (step S103E). Then, the ECU 23E executes the above step S104.

[0108] Next, the ECU 23E again acquires the detection value of the hydraulic pressure sensor 50 (step S105E). Then, the ECU 23E calculates the difference between the detection value of the hydraulic pressure sensor 50 acquired in step S103E and the detection value of the hydraulic pressure sensor 50 acquired in step S105E as the pressure change amount (step S106E).

[0109] Next, the ECU 23E corrects the fuel consumption amount corresponding to the injection amount command value calculated in step S102 by using the correction map data stored in the map memory 21E (step S107E). Specifically, the ECU 23E obtains a correction amount corresponding to the hydraulic pressure change amount from the correction map data, and corrects the fuel consumption amount by using the correction amount. After that, the ECU 23E executes the above steps S108 to S110.

[0110] Here, pressure change amount calculation unit 33E executes steps S103E, S105E, and S106E. Fuel consumption correction unit 34E executes step S107E.

[0111] In this embodiment, the amount of change (oil pressure change amount) between the oil pressure of the hydraulic pump 13 before the gas fuel is injected from the injector 12 and the oil pressure of the hydraulic pump 13 after the gas fuel is injected from the injector 12 is calculated. Then, the amount of fuel consumption corresponding to the injection amount of the gas fuel is corrected according to the amount of oil pressure change of the hydraulic pump 13. Therefore, even under a situation in which the load of the engine 3 is likely to change from the time the injection amount of the gas fuel is determined until the gas fuel is actually injected from the injector 12, the difference between the integrated value of the fuel consumption amount and the actual value of the fuel consumption amount is reduced.

[0112] The present invention is not limited to the above embodiment. For example, in the above embodiment, the injection amount command value calculated based on the accelerator opening and the engine speed is determined as the injection amount of the gas fuel, and the fuel consumption amount corresponding to the injection amount command value is corrected, but the present invention is not particularly limited to such a form. For example, the injection amount of the gas fuel may be calculated from the drive signal output to the injector 12, and the fuel consumption amount corresponding to the injection amount may be corrected.

[0113] In addition, in the above embodiment, information regarding the state of the engine 3 is obtained after the injection amount of gaseous fuel is determined and before the gaseous fuel is injected from the injector 12, but this is not particularly limited, and information regarding the state of the engine 3 may be obtained before the injection amount of gaseous fuel is determined.

[0114] In the above embodiment, LPG is used as the fuel, but the present invention is not limited to this. The present invention is also applicable to engines that use, for example, CNG (compressed natural gas) as long as the gas fuel is injected from the injector 12.

[0115] In an engine that uses CNG as fuel, the CNG is filled in a gaseous state in a CNG tank. In this case, it is possible to detect the pressure or temperature in the CNG tank and estimate the fuel consumption based on the detected value, but this has the problem of a large estimation error. It is also possible to install a flow meter in the CNG tank and directly detect the flow rate of CNG, but this raises the problem of increased costs and inability to install. By correcting the fuel consumption as in the above embodiment, it is possible to reduce costs and improve the calculation accuracy of the fuel consumption.

[0116] Furthermore, although the engine system of the above embodiment is mounted on industrial vehicles such as forklifts and power shovels which are subject to frequent transient operation, the present invention is also applicable to automobiles and the like. [Explanation of symbols]

[0117] 1, 1A, 1B, 1C, 1D, 1E... engine system, 2... vehicle, 3... engine, 12... injector, 13... hydraulic pump, 15... air supply section, 16... fuel supply section, 18... accelerator sensor (state detection section), 20... pressure sensor (state detection section), 21, 21A, 21B, 21C, 21D, 21E... map memory (consumption amount correction section), 24... accelerator, 31... injection amount determination section, 32... injection control section, 33... pressure change amount calculation section (state change amount calculation section), 33A... temperature change amount calculation section (state change amount calculation section) output section), 33B... pressure change amount calculation section (state change amount calculation section), 33C... temperature change amount calculation section (state change amount calculation section), 33D... accelerator opening change amount calculation section (state change amount calculation section), 33E... pressure change amount calculation section (state change amount calculation section), 34, 34A, 34B, 34C, 34D, 34E... fuel consumption correction section (consumption correction section), 35... consumption accumulation section, 40... temperature sensor (state detection section), 45... intake pressure sensor (state detection section), 46... intake air temperature sensor (state detection section), 50... oil pressure sensor (state detection section).

Claims

1. An engine system mounted on a vehicle, The engine, an air supply unit that supplies air to the engine; a fuel supply unit having an injector that injects gas fuel toward the engine; an injection amount determination unit that determines an injection amount of the gas fuel from the injector; an injection control unit that controls the injector so as to inject the gas fuel in accordance with the injection amount determined by the injection amount determination unit; A state detection unit that detects information regarding the state of the engine; a state change amount calculation unit that calculates an amount of change between information about the state of the engine detected by the state detection unit before the gaseous fuel is injected from the injector and information about the state of the engine detected by the state detection unit after the gaseous fuel is injected from the injector; a consumption amount correction unit that corrects a fuel consumption amount corresponding to the injection amount determined by the injection amount determination unit in accordance with the change amount calculated by the state change amount calculation unit; a consumption integrating unit that integrates the fuel consumption corrected by the consumption correcting unit.

2. 2. The engine system according to claim 1, wherein the state change amount calculation unit calculates the amount of change between information regarding the state of the engine detected by the state detection unit after the injection amount determination unit has determined the injection amount and before the gaseous fuel is injected from the injector, and information regarding the state of the engine detected by the state detection unit after the gaseous fuel is injected from the injector.

3. 3. The engine system according to claim 1, wherein the state detection unit detects the pressure or temperature of the gaseous fuel upstream of the injector as the information relating to the state of the engine.

4. 3. The engine system according to claim 1, wherein the state detection unit detects a pressure or a temperature of air supplied to the engine as the information relating to the state of the engine.

5. 3. The engine system according to claim 1, wherein the state detection unit detects an accelerator opening of the vehicle as the information relating to the state of the engine.

6. 3. The engine system according to claim 1, wherein the state detection unit detects an oil pressure of a hydraulic pump driven by the engine as the information relating to the state of the engine.

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