JP2012211524A - Fuel injection control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately control the injection of gaseous fuel even when a gaseous fuel injection valve is coupled to an air intake pipe via a tubular member.SOLUTION: A fuel injection control device controls the gaseous fuel injection valve 4 coupled to the air intake pipe via the tubular member. The fuel injection control device is configured: to calculate the amount of gaseous fuel remaining in the tubular member based on the capacity of the tubular member and an internal pressure of the air intake pipe every time a gaseous fuel injection amount is calculated; to calculate the mount of gaseous fuel to be injected in the current injection based on the amount of remaining gaseous fuel in the previous injection and the amount of remaining gaseous fuel in the current injection; and controlling the gaseous fuel injection valve 4 according to the result of the calculation.

Description

 The present invention relates to a fuel injection control device.

In the following Patent Document 1, each gas fuel injection is based on the absolute pressure and temperature of the gas fuel in the gas fuel supply pipe and a state quantity calculation coefficient set in advance corresponding to each gas fuel injection valve. A technique is disclosed in which the absolute pressure and temperature of gas fuel when being injected from a valve are calculated, and the fuel injection amount for each gas fuel injection valve is calculated based on the calculation result.
Thus, in a system for supplying gas fuel to a single engine, the gas fuel injection valve is attached to the intake pipe so that the fuel injection port of the gas fuel injection valve is exposed in the intake pipe, and the gas fuel injection valve is connected to the intake pipe. A configuration in which gas fuel is directly injected is common.

JP 2000-87771 A

By the way, in a bi-fuel system that selectively supplies gasoline fuel and gas fuel to a single engine, the gas fuel injection valve is installed at a position away from the intake pipe, and the gas fuel injection valve and intake pipe are connected by a hose or the like. Sometimes connected. In this case, even if gas fuel of the cylinder required fuel amount is injected from the gas fuel injection valve, the amount of fuel actually supplied into the cylinder is affected by the gas fuel remaining in the hose, and the cylinder required fuel amount It will be different from the amount.
For example, when accelerating, the amount of fuel supplied into the cylinder is less than the required fuel amount of the cylinder and leaning occurs, and when decelerating, the amount of fuel supplied into the cylinder is greater than the required fuel amount of cylinder and enrichment occurs. Therefore, there is a possibility of causing deterioration of exhaust gas and acceleration.

In addition, the gas fuel staying in the hose flows into the intake pipe at a timing other than the injection timing, and at the next injection timing of the same cylinder, the amount of fuel supplied into the cylinder is larger than the cylinder required fuel amount. Richness may occur.
Furthermore, since the length of each hose differs depending on the attachment position of the intake pipe to each cylinder, if the gas fuel staying in the hose flows into the intake pipe at the injection timing of other cylinders or other timing, It becomes difficult to accurately control the actual fuel supply amount with respect to the cylinder required fuel amount.

   The present invention has been made in view of the above-described circumstances, and a fuel injection control device capable of realizing highly accurate gaseous fuel injection control even when a gaseous fuel injection valve is connected to an intake pipe via a tubular member. The purpose is to provide.

 In order to solve the above-described problems, the present invention provides a fuel injection control device for controlling a gaseous fuel injection valve connected to an intake pipe via a tubular member as a first solution means related to a fuel injection control device. Each time the calculation timing of the gaseous fuel injection amount arrives, the gaseous fuel residence amount of the tubular member is calculated based on the volume of the tubular member and the internal pressure of the intake pipe, and the gaseous fuel residence amount at the previous injection and A gaseous fuel injection amount at the time of the current injection is calculated based on a gaseous fuel retention amount at the time of the current injection, and the gaseous fuel injection valve is controlled according to the calculation result.

Further, in the present invention, as a second solving means related to the fuel injection control device, in the first solving means, the volume Vh of the tubular member, the internal pressure Pintake of the intake pipe, the atmospheric pressure Patm, the gaseous fuel density ρgas. And the gaseous fuel retention amount Th of the tubular member is calculated based on the following equation (1) consisting of the retention correction coefficient Kgash corresponding to the engine operating conditions.
Th = Vh × Pintake / Patm × ρgas × Kgash (1)

Further, in the present invention, as a third solving means related to the fuel injection control device, in the second solving means, the gaseous fuel retention amount Th during the current injection, the gaseous fuel retention amount Thz during the previous injection, and The gaseous fuel injection amount Tinj at the time of the current injection is calculated based on the following equation (2) consisting of the cylinder required fuel amount Tinjb.
Tinj = Tinjb + Th-Thz (2)

  Further, in the present invention, as a fourth solving means related to the fuel injection control device, in any one of the first to third solving means, corresponding to each of a plurality of cylinders, the tubular member is interposed. When a gas fuel injection valve connected to the intake pipe is arranged, the gas fuel retention amount of the tubular member is calculated for each cylinder, and the gas fuel retention amount at the previous injection and the gas fuel retention at the current injection are calculated. The gaseous fuel injection amount at the time of the current injection is calculated based on the amount.

 According to the present invention, whenever the calculation timing of the gaseous fuel injection amount arrives, the gaseous fuel residence amount of the tubular member is calculated based on the volume of the tubular member and the internal pressure of the intake pipe, and the gaseous fuel residence time at the previous injection is calculated. Gas fuel injection amount at the time of current injection is calculated based on the amount and the amount of gas fuel retained at the time of current injection, and the gas fuel injection valve is controlled according to the calculation result. Even when connected to the intake pipe, highly accurate gaseous fuel injection control can be realized.

It is a schematic structure figure of the bi-fuel system concerning this embodiment. It is a figure which shows a mode that gaseous fuel stagnates in each fuel hose 5a-5d. (A) represents a main routine of gas fuel injection control that is executed every time the 2nd-ECU 9 calculates the gas fuel injection amount for each of the cylinders 1a to 1d. (B) to (d) It is a flowchart showing the subroutine of each process in a main routine. The gas fuel injection amount Tinj (corrected injection execution amount in the figure) calculated according to FIG. 3, the gas fuel injection amount (uncorrected injection execution amount in the figure) calculated by the conventional method, and the cylinder required fuel injection amount Tinjb 6 is a timing chart showing the temporal correspondence relationship with intake pressure Pintake.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic configuration diagram of a bi-fuel system according to the present embodiment. In FIG. 1, reference numeral 1 denotes, for example, a cylinder block of an in-line four cylinder engine. The cylinder block 1 includes four cylinders (first cylinder 1a, second cylinder 1b, third cylinder 1c, and fourth cylinder 1d) arranged in series.

  Reference numeral 2 denotes an intake manifold that is mounted on the cylinder block 1 and distributes the air taken in from the outside to each of the four cylinders 1a to 1d. One end of the intake manifold 2 branches into four intake pipes (a first intake pipe 2a, a second intake pipe 2b, a third intake pipe 2c, and a fourth intake pipe 2d) and is connected to the cylinders 1a to 1d. The air introduced from the air inlet 2e provided at the other end is distributed to the cylinders 1a to 1d via the intake pipes 2a to 2d.

 Reference numeral 3 is a gas fuel distributor, reference numeral 4a is a first gas injector, reference numeral 4b is a second gas injector, reference numeral 4c is a third gas injector, reference numeral 4d is a fourth gas injector, reference numeral 5a is a first fuel hose, reference numeral 5b Is a second fuel hose, reference numeral 5c is a third fuel hose, and reference numeral 5d is a fourth fuel hose.

 The gas fuel distributor 3 distributes gas fuel supplied from a gas fuel tank (not shown) via a shut-off valve, a regulator, a filter, and the like to the gas injectors 4a to 4d. Each of the gas injectors 4a to 4d is a gas fuel injection valve (for example, a solenoid valve) installed at a position away from each of the intake pipes 2a to 2d, and each of the fuel hoses 5a to 5d (communication with the fuel injection port). It is connected with each intake pipe 2a-2d via the tubular member.

 That is, the gas fuel injected from the first gas injector 4a is supplied into the first intake pipe 2a via the first fuel hose 5a, and the gas fuel injected from the second gas injector 4b passes through the second fuel hose 5b. The gas fuel supplied into the second intake pipe 2b through the third gas injector 4c is supplied into the third intake pipe 2c through the third fuel hose 5c and injected from the fourth gas injector 4d. The gas fuel is supplied into the fourth intake pipe 2d through the fourth fuel hose 5d. The lengths of the fuel hoses 5a to 5d differ depending on the attachment positions of the intake pipes 2a to 2d with respect to the cylinder block 1.

 Reference numeral 6a is a first gasoline injector, reference numeral 6b is a second gasoline injector, reference numeral 6c is a third gasoline injector, reference numeral 6d is a fourth gasoline injector, and reference numeral 7 is a gasoline fuel distribution pipe. The gasoline fuel distribution pipe 7 distributes gasoline fuel supplied from a gasoline fuel tank (not shown) to the gasoline injectors 6a to 6d. Each of the gasoline injectors 6a to 6d is a gasoline fuel injection valve (for example, a solenoid valve) installed so that the fuel injection port is exposed in the combustion chamber of each cylinder 1a to 1d.

 That is, the gasoline fuel injected from the first gasoline injector 6a is directly supplied into the combustion chamber of the first cylinder 1a, and the gasoline fuel injected from the second gasoline injector 6b is directly supplied into the combustion chamber of the second cylinder 1b. The gasoline fuel injected from the third gasoline injector 6c is directly supplied into the combustion chamber of the third cylinder 1c, and the gasoline fuel injected from the fourth gasoline injector 6d is directly supplied into the combustion chamber of the fourth cylinder 1d. In addition, you may install each gasoline injector 6a-6d so that a fuel injection port may be exposed inside each intake pipe 2a-2d, respectively.

Reference numeral 8 denotes a 1st-ECU (Electronic Control Unit), reference numeral 9 denotes a 2nd-ECU, and reference numeral 10 denotes a fuel changeover switch. The 1st-ECU 8 calculates the gasoline fuel injection amount and the gasoline fuel injection timing based on various sensor signals input from various sensors (not shown) for detecting the engine state, and for gasoline injector energization according to the calculation results. A pulse signal is generated and output to the 2nd-ECU 9.
Specifically, the pulse width of the gasoline injector energizing pulse signal is set according to the gasoline fuel injection amount, and the rising timing of the gasoline injector energizing pulse signal is set according to the gasoline fuel injection timing.

The various sensor signals input to the 1st-ECU 8 include at least a crank pulse signal having a period for which the crankshaft rotates by a certain angle as one period, and a TDC having a period for the piston reaching top dead center (TDC) as one period. A pulse signal, an intake air temperature signal indicating the intake air temperature, an intake air pressure signal indicating the intake air pressure, a cooling water temperature signal indicating the cooling water temperature, and the like are included.
The 1st-ECU 8 calculates the engine speed from the crank pulse signal, calculates the gasoline fuel injection amount based on the engine speed and the intake air temperature (or the cooling water temperature), and further calculates the gasoline fuel injection timing from the gasoline fuel injection amount. (Crankshaft angle at which gasoline fuel should be injected) is calculated. Note that the method for calculating the gasoline fuel injection amount and the gasoline fuel injection timing is the same as the conventional method, and a detailed description thereof will be omitted.

 The 2nd-ECU 9 (fuel injection control device) receives various sensor signals input from various sensors for detecting the engine state, a gasoline injector energization pulse signal input from the 1st-ECU 8, and a fuel pressure sensor (not shown). Gas injectors 4a to 4d and gasoline injectors based on a gas fuel pressure signal, a gas fuel temperature signal input from a fuel temperature sensor (not shown), and a fuel selection signal input from the fuel changeover switch 10. The energization control of 6a-6d is performed.

 Specifically, when the 2nd-ECU 9 detects that the gasoline fuel is selected based on the fuel selection signal input from the fuel changeover switch 10, the 2nd-ECU 9 enters the gasoline fuel injection mode and is input from the 1st-ECU 8. A pulse signal having the same pulse width and rising timing as the gasoline injector energization pulse signal, that is, a gasoline injector energization pulse signal PL is output to each of the gasoline injectors 6a to 6d.

 When the 2nd-ECU 9 detects that the gas fuel is selected based on the fuel selection signal input from the fuel changeover switch 10, the gas fuel injection mode is set, and the gas fuel pressure signal, the gas fuel temperature signal, A gas injector energization pulse signal PG is generated based on the gasoline injector energization pulse signal input from the 1st-ECU 8, and is output to each of the gas injectors 4a to 4d. Details of the operation in the gas fuel injection mode will be described later.

 The fuel changeover switch 10 is a switch that enables fuel change by manual operation, and indicates the state of the switch, that is, whether gasoline fuel is selected as fuel used in the engine or gas fuel is selected. A fuel selection signal is output to the 2nd-ECU 9.

Next, the operation of the bi-fuel system configured as described above, particularly the operation in the gas fuel injection mode of the 2nd-ECU 9 that is a feature of the present embodiment will be described.
As already described, when the gas injectors 4a to 4d and the intake pipes 2a to 2d are connected by the fuel hoses 5a to 5d, the gas fuel of the cylinder required fuel amount is injected from the gas injectors 4a to 4d. However, the amount of fuel actually supplied into each of the cylinders 1a to 1d differs from the cylinder required fuel amount under the influence of the gas fuel staying in each of the fuel hoses 5a to 5d.

 For example, focusing on the first gas injector 4a, during acceleration, the throttle valve opens and the internal pressure (intake pressure) of the first intake pipe 2a changes to the positive pressure side, so that the first pressure is higher than the internal pressure of the first fuel hose 5a. The internal pressure of the intake pipe 2a becomes larger. When gas fuel is injected from the first gas injector 4a in this state, the fuel density in the first fuel hose 5a increases and the amount of fuel that stays in the first fuel hose 5a (gas fuel retention amount) increases. The amount of fuel flowing out into the first intake pipe 2a is smaller than the required cylinder fuel amount, and leaning occurs (see FIGS. 2A to 2C).

 Further, at the time of deceleration, the throttle valve is closed and the internal pressure (intake pressure) of the first intake pipe 2a changes to the negative pressure side, so that the internal pressure of the first intake pipe 2a is greater than the internal pressure of the first fuel hose 5a. Get smaller. In this state, when the gas fuel is injected from the first gas injector 4a, the fuel density in the first fuel hose 5a is reduced, and the gas fuel retention amount in the first fuel hose 5a is reduced, while the first intake pipe 2a. The amount of fuel that flows into the cylinder increases more than the required cylinder fuel amount, and richening occurs (see FIGS. 2D to 2F).

 In contrast to such a phenomenon, in this embodiment, every time the calculation timing of the gas fuel injection amount arrives, from the hose volume of each fuel hose 5a to 5d and the internal pressure (intake pressure) of each intake pipe 2a to 2d, By calculating the gas fuel retention amount of each fuel hose 5a-5d and calculating the gas fuel injection amount at the current injection from the gas fuel retention amount at the previous injection and the gas fuel retention amount at the current injection, high accuracy The gas fuel injection control is realized.

 Specifically, the 2nd-ECU 9 performs gas fuel injection control according to the flowchart shown in FIG. 3 in the gas fuel injection mode. FIG. 3A shows a main routine of gas fuel injection control executed by the 2nd-ECU 9 every time the calculation timing of the gas fuel injection amount arrives, and FIGS. 3B to 3D show each of the main routines. This represents a processing subroutine.

 As shown in FIG. 3A, when the calculation timing of the gas fuel injection amount comes, the 2nd-ECU 9 first calculates the cylinder required fuel amount (step S1). Specifically, the 2nd-ECU 9 calculates the gasoline fuel injection amount based on the engine speed and the intake air temperature (which may be the cooling water temperature) obtained from the various sensor signals, and the gas fuel correction coefficient is calculated as the gasoline fuel injection amount. Is calculated to calculate the cylinder required injection amount. The 2nd-ECU 9 acquires a gas fuel correction coefficient corresponding to the gas fuel pressure and the gas fuel temperature by searching the gas fuel correction table.

 Hereinafter, in step S1, the cylinder required fuel amount calculated for the first cylinder 1a is represented by Tinjb [1], the cylinder required fuel amount calculated for the second cylinder 1b is represented by Tinjb [2], and the third The cylinder required fuel amount calculated for the cylinder 1c is represented by Tinjb [3], and the cylinder required fuel amount calculated for the fourth cylinder 1d is represented by Tinjb [4].

 Subsequently, the 2nd-ECU 9 calculates the gas fuel retention amount during the current injection according to the subroutine shown in FIG. 3B (step S2). Specifically, as shown in FIG. 3B, the 2nd-ECU 9 increments the control variable Cyl whose initial value is set to “0” (step S2a), and determines whether the fuel cut state or the engine stop state exists. Is determined (step S2b).

The 2nd-ECU 9 includes the hose volume Vh [Cyl], the intake pressure Pintake, the atmospheric pressure Patm, the gas fuel density ρgas, and the stagnation correction coefficient Kgash according to the engine operating conditions when “No” in step S2b. Based on the equation (3), the gas fuel retention amount Th [Cyl] at the time of the current injection is calculated (step S2c).
Th [Cyl] = Vh [Cyl] × Pintake / Patm × ρgas × Kgash (3)

 In the above equation (3), the hose volume Vh [Cyl] indicates the volume of the Cylth fuel hose, and the gas fuel retention amount Th [Cyl] indicates the gas fuel retention amount of the Cylth fuel hose. Yes. That is, for example, when the control variable Cyl is “1”, the hose volume Vh [1] indicates the volume of the first fuel hose 5a, and the gas fuel retention amount Th [1] is the gas fuel retention amount of the first fuel hose 5a. Will be shown. These hose volumes Vh [Cyl] are fixed values obtained in advance from the lengths and inner diameters of the fuel hoses 5a to 5d.

 In the above equation (3), the intake pressure Pintake is a detected value obtained from the intake pressure sensor, and the atmospheric pressure Patm and the gas fuel density ρgas are preset fixed values. The stay correction coefficient Kgash is a fixed value set as table data in advance according to engine operating conditions such as the engine speed and load state. That is, the 2nd-ECU 9 searches the stay correction coefficient table to obtain the stay correction coefficient Kgash corresponding to the engine speed, load state, and the like obtained from various sensor signals.

 On the other hand, if “Yes” in step S2b, the 2nd-ECU 9 sets an initial value determined in advance as the gas fuel retention amount Vh [Cyl] at the time of the current injection (step S2d), and further the previous injection A predetermined initial value is set as the gas fuel retention amount Vhz [Cyl] at the time (step S2e).

 The 2nd-ECU 9 determines whether or not there is a loop end after the execution of step S2c or step S2e, that is, whether or not the control variable Cyl matches the number of cylinders (here, “4”) (step S2f). If “No” (Cyl <4), the process returns to the process of step S2a. If “Yes” (Cyl = 4), this subroutine is terminated and the process returns to the main routine.

 In accordance with the subroutine shown in FIG. 3B, the 2nd-ECU 9 causes the gas fuel retention amount Th [1] during the current injection of the first fuel hose 5a and the gas fuel retention amount during the current injection of the second fuel hose 5b. Th [2], the gas fuel retention amount Th [3] at the time of current injection of the third fuel hose 5c, and the gas fuel retention amount Th [4] at the time of current injection of the fourth fuel hose 5d are calculated.

The 2nd-ECU 9 returns to the main routine of FIG. 3A after the completion of the above-described subroutine of FIG. 3B, and calculates the effective injection amount of the gas fuel, that is, the gas fuel injection amount at the time of the current injection (step). S3). Specifically, the 2nd-ECU 9 increments the control variable Cyl whose initial value is set to “0” according to the subroutine of FIG. 3C (step S3a), and the gas fuel retention amount Th [ Cyl], gas fuel retention amount Thj [Cyl] at the time of the current injection is calculated based on the following equation (4) consisting of gas fuel retention amount Thz [Cyl] at the previous injection and cylinder required fuel amount Tinjb [Cyl] (Step S3b).
Tinj [Cyl] = Tinjb [Cyl] + Th [Cyl] -Thz [Cyl] (4)

 After the execution of step S3b, the 2nd-ECU 9 determines whether or not there is a loop end, that is, whether or not the control variable Cyl matches the number of cylinders (here, “4”) (step S3c). "(Cyl <4), the process returns to the process of step S3a. On the other hand, if" Yes "(Cyl = 4), the present subroutine is terminated and the process returns to the main routine.

 According to the subroutine of FIG. 3C, the 2nd-ECU 9 causes the gas fuel injection amount Tinj [1] at the time of current injection to the first cylinder 1a and the gas fuel injection amount Tinj [1 at the time of current injection to the second cylinder 1b. 2], a gas fuel injection amount Tinj [3] at the time of current injection for the third cylinder 1c, and a gas fuel injection amount Tinj [4] at the time of current injection for the fourth cylinder 1d are calculated.

  2nd-ECU9 returns to the main routine of Fig.3 (a) after completion | finish of the subroutine of FIG.3 (c) mentioned above, and performs gas fuel injection (step S4). Specifically, the 2nd-ECU 9 synchronizes with the rising timing (that is, fuel injection timing) of the pulse signal for energizing the gasoline injector corresponding to the first cylinder 1a input from the 1st-ECU 8 (ie, the fuel injection timing Tinj [ 1], a gas injector energization pulse signal PG having a pulse width corresponding to 1] is output to the first gas injector 4a.

In addition, the 2nd-ECU 9 synchronizes with the rising timing of the gasoline injector energization pulse signal corresponding to the second cylinder 1b, and has a pulse width corresponding to the gas fuel injection amount Tinj [2]. Is output to the second gas injector 4b.
Further, the 2nd-ECU 9 synchronizes with the rising timing of the gasoline injector energization pulse signal corresponding to the third cylinder 1c, and the gas injector energization pulse signal PG having a pulse width corresponding to the gas fuel injection amount Tinj [3]. Is output to the third gas injector 4c.
Further, the 2nd-ECU 9 synchronizes with the rising timing of the gasoline injector energization pulse signal corresponding to the fourth cylinder 1d, and the gas injector energization pulse signal PG having a pulse width corresponding to the gas fuel injection amount Tinj [4]. Is output to the fourth gas injector 4d.

 Finally, the 2nd-ECU 9 ends the main routine after updating the gas fuel retention amount Thz [Cyl] at the previous injection according to the subroutine shown in FIG. 3D (step S5). Specifically, as shown in FIG. 3 (d), the 2nd-ECU 9 sets the number of the cylinder in which the fuel injection has been performed to the control variable Cyl (step S5a), and further, the gas fuel retention amount during the current injection Th [Cyl] is set as the gas fuel retention amount Thz [Cyl] at the previous injection (step S5b).

 FIG. 4 shows the gas fuel injection amount Tinj (corrected injection execution amount in the figure) calculated by the 2nd-ECU 9 according to FIG. 3, and the gas fuel injection amount calculated by the conventional method (uncorrected injection execution amount in the figure). 4 is a timing chart showing a temporal correspondence relationship between the cylinder required fuel injection amount Tinjb and the intake pressure Pintake.

 As can be seen from FIG. 4, at the time of acceleration (when the intake pressure Pintake increases), the gas fuel injection amount Tinj is increased to compensate for the shortage of fuel from the cylinder required fuel injection amount Tinjb. The amount of fuel supplied to the cylinder substantially matches the cylinder required fuel injection amount Tinjb. On the other hand, when decelerating (when the intake pressure Pintake decreases), the gas fuel injection amount Tinj is reduced so as to compensate for the excess fuel from the cylinder required fuel injection amount Tinjb, so the fuel actually supplied to the cylinder The amount substantially coincides with the cylinder required fuel injection amount Tinjb.

 As described above, according to the present embodiment, every time the calculation timing of the gas fuel injection amount arrives, from the hose volume of each fuel hose 5a to 5d and the internal pressure (intake pressure) of each intake pipe 2a to 2d. The gas fuel retention amount of each of the fuel hoses 5a to 5d is calculated, and the gas fuel injection amount at the current injection is calculated from the gas fuel retention amount at the previous injection and the gas fuel retention amount at the current injection. Accordingly, the gas injectors 4a to 4d are controlled accordingly, so even when the gas injectors 4a to 4d are connected to the intake pipes 2a to 2d via the fuel hoses 5a to 5d, highly accurate gas fuel injection control is performed. Can be realized.

Although one embodiment of the present invention has been described above, this embodiment is merely an example, and it is needless to say that various details of the embodiment can be changed without departing from the spirit of the present invention.
For example, in the above-described embodiment, the bi-fuel system provided with the 1st-ECU 8 and the 2nd-ECU 9 separately is illustrated, but a configuration in which the functions of these two ECUs are integrated into one ECU may be adopted. .
In the above-described embodiment, the bi-fuel system has been described as an example. However, the present invention is not limited to this, and even a mono-fuel system that supplies only gas fuel to a single engine may be provided via a tubular member. The present invention can be applied to any system in which a gaseous fuel injection valve connected to the intake pipe is provided.

  DESCRIPTION OF SYMBOLS 1 ... Cylinder block, 1a ... 1st cylinder, 1b ... 2nd cylinder, 1c ... 3rd cylinder, 1d ... 4th cylinder, 2 ... Intake manifold, 2a ... 1st intake pipe, 2b ... 2nd intake pipe, 2c ... 3rd intake pipe, 2d ... 4th intake pipe, 4a ... 1st gas injector, 4b ... 2nd gas injector, 4c ... 3rd gas injector, 4d ... 4th gas injector, 5a ... 1st fuel hose, 5b ... 1st 2 fuel hose, 5c ... 3rd fuel hose, 5d ... 4th fuel hose, 9 ... 2nd-ECU (fuel injection control device)

Claims (4)

A fuel injection control device for controlling a gaseous fuel injection valve connected to an intake pipe via a tubular member,
Each time the calculation timing of the gaseous fuel injection amount arrives, the gaseous fuel retention amount of the tubular member is calculated based on the volume of the tubular member and the internal pressure of the intake pipe, and the gaseous fuel retention amount at the time of the previous injection and this time A fuel injection control device that calculates a gaseous fuel injection amount at the time of current injection based on a gaseous fuel retention amount at the time of injection, and controls the gaseous fuel injection valve according to the calculation result. Based on the following equation (1) consisting of the volume Vh of the tubular member, the internal pressure Pintake of the intake pipe, the atmospheric pressure Patm, the gas fuel density ρgas, and the residence correction coefficient Kgash according to the engine operating conditions, 2. The fuel injection control device according to claim 1, wherein a gaseous fuel retention amount Th is calculated.
Th = Vh × Pintake / Patm × ρgas × Kgash (1) Based on the following equation (2) consisting of the gaseous fuel retention amount Th during the current injection, the gaseous fuel retention amount Thz during the previous injection, and the cylinder required fuel amount Tinjb, the gaseous fuel injection amount Tinj during the current injection is The fuel injection control device according to claim 2, wherein the fuel injection control device calculates the fuel injection control device.
Tinj = Tinjb + Th-Thz (2)   Corresponding to each of a plurality of cylinders, when a gaseous fuel injection valve connected to an intake pipe via the tubular member is arranged, for each cylinder, calculate the gaseous fuel retention amount of the tubular member, The fuel according to any one of claims 1 to 3, wherein a gaseous fuel injection amount at the time of current injection is calculated based on a gaseous fuel retention amount at the time of previous injection and a gaseous fuel retention amount at the time of current injection. Injection control device.

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