JP2000234551A - Accumulator fuel injection control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce white smoke which may increase engine noises during warming-up until temperature of engine cooling water is sufficiently heated after cold starting. SOLUTION: High pressure fuel pressurized by a fuel pump 1 is stored in a high pressure accumulator 3, supplied to an injector 9 through a changeover valve 5 and a fuel passage 10a, and stored in a low pressure accumulator 4 connected to the fuel passage 10a. An electronic control unit 8 so controls the changeover valve 5 as to pass the fuel in the high pressure accumulator 3 to the low pressure accumulator 4, while opens a pressure control valve 34 so as to obtain fuel pressure of a preset value in the low pressure accumulator 4. The ECU 8 divides engine starting into a normal starting and a low temperature starting according to the temperature of engine cooling water. In the low temperature starting, only the fuel pressure in the low pressure accumulator 4 is set higher than the normal starting. The injector 9 alone is opened for performing initial injection. The changeover valve 5 is opened during the opening of the injector 9 for performing main injection. It is possible to prevent generation of white smoke and reduce combustion noises.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an accumulator type fuel injection control device.

[0002]

2. Description of the Related Art As a fuel injection device for a diesel engine, a high pressure fuel accumulated in an accumulator is stably supplied to each cylinder of the engine to improve the engine performance in a wide operating range from a low speed range to a high speed range. There is a type fuel injection device (common rail system). Even when such a fuel injection device is used, if the fuel injection rate immediately after the start of fuel injection is excessive, rapid explosion combustion is performed at the beginning of combustion, which not only increases engine noise but also increases exhaust gas emissions. Nitrogen oxides (NOx) increase.

In order to solve such a problem, a pressure-accumulation type fuel injection device which injects fuel at a low fuel injection rate in an initial stage of each fuel injection cycle has been proposed. The fuel injection device according to this proposal selectively communicates, for example, a low-pressure accumulator for storing low-pressure fuel, a high-pressure accumulator for storing high-pressure fuel, and a low-pressure accumulator or a high-pressure accumulator to an injector (fuel injection nozzle). A switching valve for switching the fuel injection rate by controlling the fuel injection rate, and an on-off valve for controlling the fuel injection timing by connecting / disconnecting the pressure control chamber of the injector and the fuel tank.

[0004] Regarding the fuel pressure formation in the pressure accumulator, a pressure accumulating fuel injection device of a type that obtains high pressure fuel by a high pressure fuel pump and regulates high pressure fuel introduced into the low pressure accumulator to obtain low pressure fuel (for example, WO98 / 09068) For example, by closing the on-off valve for fuel injection timing control provided corresponding to the injector of each cylinder and switching the switching valve for switching the fuel injection rate to the low pressure side, for example, the fuel chamber ( Low-pressure fuel in the fuel reservoir) and keep the injector closed, and when the fuel injection start time arrives, open the on-off valve, open the injector, and inject low-pressure fuel from the nozzle to initiate low-pressure injection. (Hereinafter referred to as “low-pressure injection”), and when the low-pressure injection period has elapsed, the switching valve is switched to the high-pressure side, and the high-pressure fuel from the high-pressure accumulator is supplied to the nozzle. By al injected perform high pressure main injection (hereinafter referred to as "high-pressure injection"), it closes the on-off valve with the switching valve when the injection end timing comes switched to the low pressure side. That is, the switching valve switches between the low-pressure accumulator and the high-pressure accumulator during fuel injection to control the fuel injection waveform.

[0005] In the low-pressure accumulator, after the switching valve is closed, the high-pressure fuel accumulated between the switching valve and the fuel chamber of the injector is regulated to obtain low-pressure fuel. That is, the pressure control valve of the low-pressure accumulator connected to the fuel passage between the low-pressure accumulator and the fuel tank is duty-controlled so that the fuel pressure in the low-pressure accumulator becomes a predetermined pressure. The fuel is discharged to the fuel tank (open to the atmosphere).

[0006]

By the way, in the pressure accumulating type fuel injection device having the above-mentioned structure for controlling the injection waveform by switching between the low pressure accumulator and the high pressure accumulator during fuel injection, If low-pressure injection is performed during warm-up before the engine coolant temperature rises sufficiently, unburned or incompletely combusted fuel is discharged due to the low combustion chamber temperature, and white smoke is easily generated.

[0007] As an engine warm-up operation control device, for example, there is one disclosed in Japanese Patent Application Laid-Open No. 8-28321. This warm-up operation control device is intended to maintain the heating performance at the time of idling operation of the engine. When a heating switch is turned on, a warm-up control mode is entered, and the pressure of the accumulator is increased to increase the fuel injection. By increasing the injection pressure over the entire period, the load on the high-pressure fuel supply pump, that is, the engine load is increased, and as a result, the fuel amount is increased while the engine speed remains the same, and warm-up is promoted.

However, this warm-up operation control device is
Since the accumulator type fuel injection device using a single accumulator is used, the fuel injection waveform becomes a high-pressure rectangle, and in the warm-up control, the pressure increases from the initial injection to a higher pressure. The amount of fuel injected and mixed into the cylinder increases, and the amount of premixed combustion increases. As a result, there is a problem that the in-cylinder pressure rises and noise increases.

Further, since the main purpose is to maintain the heating performance at the time of idling, the rotation range of the engine is limited, and the engine speed at the time of warm-up immediately after starting at low temperature (normally, idle rotation at maximum +500 to 600 rpm) is reduced. There is a problem that white smoke reduction during warm-up immediately after starting at low temperature (when the engine cooling water temperature is considerably lower than during normal operation) is not addressed.

For this reason, according to the present invention, a pressure-accumulation type fuel for reducing white smoke without increasing engine noise during warm-up until the engine cooling water temperature is sufficiently increased after starting in a low temperature state such as a cold region. It is intended to provide an injection control device.

[0011]

According to a first aspect of the present invention, high-pressure fuel pressurized by a fuel pump is stored in a first accumulator, and a first control valve and a fuel passage are provided. The fuel pressure is supplied to a fuel injection nozzle that injects the fuel into the combustion chamber of the engine through a branch passage, and is connected to the fuel passage through a branch passage, and the second pressure is lower than the fuel pressure in the first accumulator.
It is supplied to the accumulator and stored. The fuel pressure of the second pressure accumulator is controlled by a second control valve that discharges the fuel in the second pressure accumulator to the atmosphere open side. The fuel control means includes:
The first control valve is controlled to open to discharge the high-pressure fuel in the accumulator toward the second accumulator, and the second control valve is controlled to set the fuel pressure of the second accumulator to a set pressure. Control valve opening.

The fuel control means divides the engine start into two modes, a normal start and a low temperature start, in accordance with the engine coolant temperature. In the low temperature start, only the second accumulator is set to have a higher fuel pressure than the normal start. Only the fuel injection nozzle is opened to perform the initial injection. The main injection is performed by opening the first control valve in the middle of the fuel injection nozzle opening timing. This makes it possible to reduce combustion noise while reducing white smoke discharged from the engine at a low temperature start.

According to the second aspect of the present invention, when the engine load is a load, the fuel control means prohibits the increase in the pressure of the second accumulator, that is, gives priority to the engine cooling water temperature of the initial injection pressure. The injection pressure is controlled according to the load. As a result, an appropriate engine output according to the load can be obtained. According to the third aspect of the invention, the so-called boot type injection is maintained by setting the initial injection pressure at the time of the low temperature start to be smaller than the main injection pressure. Thereby, combustion noise can be suppressed.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be illustratively described in detail below with reference to the drawings. FIG. 1 is a schematic configuration diagram of an accumulator type fuel injection control device as an embodiment of the present invention, and FIG. 2 is a schematic diagram showing connection between main elements of the fuel injection control device shown in FIG. 1 and injectors of each cylinder of an engine. FIG.

In FIGS. 1 and 2, the pressure-accumulation type fuel injection control device is mounted on, for example, an in-line six-cylinder diesel engine (not shown), and the high-pressure fuel pump 1 is, for example, as shown in FIG. Two plunger pumps 20 are provided. Each of the plunger pumps 20 corresponds to the front three cylinders and the rear three cylinders of the in-line six-cylinder engine, respectively, and drives the plungers 21 of the front three cylinders and the plungers 21 of the rear three cylinders. Each cam 22 has three peaks, and each plunger 21 performs three pumping strokes to feed fuel while the high-pressure fuel pump shaft makes one rotation. Adjustment of the pressure feeding stroke
This is performed by adjusting the closing timing of the solenoid valve 23 provided on the discharge side of the plunger. While the solenoid valve 23 is open, the pressure feeding operation of the plunger pump 20 becomes invalid. I have. The solenoid valve 23 is controlled by an electronic control unit 8 described later.

Returning to FIG. 1, an electronic control unit (ECU) 8 as a fuel control means of the pressure-accumulation type fuel injection control unit is configured to control the engine speed N detected by the engine speed sensor 8a.
e, the solenoid valve 23 of the high-pressure fuel pump 1 is controlled in accordance with the accelerator pedal depression amount (accelerator opening) Acc detected by an accelerator opening sensor (not shown) as an engine load detecting means, and the pressure feeding stroke is controlled. Is variably adjusted, and the feed stroke (discharge pressure) is feedback-controlled in accordance with the fuel pressure P _HP detected by the pressure sensor 3a provided in the high-pressure accumulator (first pressure accumulator) 3, whereby the engine is controlled. High-pressure fuel suitable for operating conditions is obtained.

The fuel pressurized by the high-pressure fuel pump 1 is stored in the high-pressure accumulator 3. This high-pressure accumulator 3
It is common to each cylinder and communicates with the fuel passage 10a. In the middle of the fuel passage 10a, for example, a switching valve (first control valve) 5 for switching the fuel injection rate, which comprises a two-way solenoid valve, is used.
Is provided for each cylinder (FIG. 2), and a check valve 32 is provided immediately downstream of the switching valve 5 to allow fuel flow only from the upstream side to the downstream side.

The fuel passage 10a has a fuel passage 10b branched from the fuel passage 10a downstream of the check valve 32.
A common low-pressure accumulator (second accumulator) 4 is connected to each cylinder via the. A check valve 6 is provided in the middle of the fuel passage 10b.
And a bypass passage for bypassing the check valve 6, and an orifice 6a is provided in the bypass passage. The check valve 6 is connected between the low-pressure accumulator 4 and the fuel passage 10.
The fuel flow is allowed only in the direction a. When the fuel pressure in the fuel passage 10a is higher than the fuel pressure in the fuel passage 10b,
The fuel in the fuel passage 10a flows into the fuel passage 10b through the orifice 6a, and further flows into the low-pressure accumulator 4. A pressure control valve (second control valve) 34 that operates under the control of the electronic control unit 8 and controls the fuel pressure of the low-pressure accumulator 4 is provided between the low-pressure accumulator 4 and the fuel tank 17 in the fuel passage 10b. Have been. As shown in FIG. 2, the low-pressure accumulator 4 has a pressure sensor 4a for detecting a fuel pressure P _LP in the low-pressure accumulator 4.
Is provided.

The electronic control unit 8 detects the fuel pressure in the low-pressure accumulator 4 by the pressure sensor 4a so as to be a pressure suitable for the engine operating state represented by the engine speed Ne and the accelerator pedal depression amount Acc. The pressure control valve 34 is controlled based on the actual pressure P _LP . Further, the electronic control unit 8 determines whether the engine is started based on a cooling water temperature Tw from a temperature sensor (not shown) serving as cooling water temperature detecting means mounted on the engine and detecting the engine cooling water temperature. At the time of a low temperature start, the fuel pressure is set to the high pressure side only in the low pressure accumulator 4 and the initial injection is performed by opening only the injector 9 as the fuel injection nozzle. And the switching valve 5 is opened during the valve opening timing of the injector 9 to perform the main injection.
Further, the electronic control unit 8 gives priority to loaded operation over idle operation, and performs fuel injection control according to load to obtain an appropriate engine output.

An injector 9 provided in each cylinder of the engine has a pressure control chamber 11 and a fuel chamber (fuel pool) 1 connected to a fuel passage 10a through an orifice 15.
The pressure control chamber 11 is connected to a fuel tank 17 via an orifice 16 and a fuel return passage 10c. An on-off valve 7 for controlling the fuel injection timing, which is composed of, for example, a two-way solenoid valve, is connected in the middle of the fuel return passage 10c. Note that the on-off valve 7 may be installed in the injector.

The injector 9 has a needle valve 13 for opening and closing a nozzle (injection hole) 9a, and a hydraulic piston 14 slidably housed in the pressure control chamber 11. The needle valve 13 is a spring (see FIG. (Not shown) to the nozzle 9a side to close the valve. When fuel is supplied from the fuel passage 10a to the pressure control chamber 11 and the fuel chamber 12 and the on-off valve 7 for controlling the injection timing is closed, the resultant force of the spring force of the spring and the fuel pressure is adjusted by the needle valve 13. In addition, the needle valve 13 closes the nozzle 9a against the fuel pressure in the fuel chamber 12. When the on-off valve 7 opens and the fuel in the pressure control chamber 11 is discharged to the fuel tank 17 side (open to the atmosphere), the needle valve 13 resists the spring force of the spring due to the fuel pressure in the fuel chamber 12. And hydraulic piston 1
The nozzle 9a is opened by moving to the side 4 and fuel in the fuel chamber 12 is injected from the nozzle 9a into the combustion chamber of the engine.

Hereinafter, the operation of the fuel injection device having the above configuration in the normal mode will be described. Under the control of the electronic control unit 8, the fuel pressure in the high-pressure accumulator 3 and the fuel pressure in the low-pressure accumulator 4 are controlled so as to conform to the engine operating state, and the engine operating state (engine speed, accelerator pedal depression amount) is controlled. Etc.), a fuel injection period (fuel injection start / end timing) and a low pressure injection period are set.

As shown in FIG. 4, the switching valve 5 and the on-off valve 7 are both closed until the fuel injection start timing comes, and the low pressure fuel passage 10a is provided in the fuel passage 10a downstream of the switching valve 5. Low-pressure fuel is supplied from the pressure accumulator 4, and the low-pressure fuel is supplied to the pressure control chamber 11 and the fuel chamber 12 of the injector 9. When the on-off valve 7 is closed, the fuel pressure supplied into the pressure control chamber 11 is applied to the needle valve 13 via the hydraulic piston 14, and the nozzle 9 a
Is closed and the valve is closed.

At the fuel injection start timing, only the on-off valve 7 is opened, and the low-pressure fuel in the pressure control chamber 11 of the injector 9 is discharged to the fuel tank 17 through the orifice 16 and the fuel return passage 10c. As a result, when the resultant force of the fuel pressure applied to the needle valve 13 via the hydraulic piston 14 and the spring force of the spring becomes smaller than the fuel pressure in the fuel chamber 12 acting to push up the needle valve 13, the needle valve 13 Rises to open the nozzle 9a, and low-pressure fuel is injected from the nozzle 9a. That is, low-pressure injection is performed at a relatively low fuel injection rate (fuel injection amount per unit time) at the beginning of injection. By this low-pressure injection, the combustion in the initial stage of the fuel injection period is performed relatively slowly, and the amount of NOx in the exhaust gas is reduced.

When a predetermined time has elapsed since the start of the low-pressure injection, the switching valve 5 for switching the injection rate is opened while the on-off valve 7 for controlling the injection timing is opened, and the fuel chamber 12 is opened. High-pressure fuel is supplied, and high-pressure fuel is injected from the injector 9. That is, high-pressure injection is performed at an injection rate larger than the fuel injection rate at low-pressure injection. When the fuel injection ends, the on-off valve 7 for controlling the injection timing is closed, and the high-pressure fuel supplied from the fuel passage 10a to the pressure control chamber 11 through the orifice 15 is supplied to the needle valve 13 via the hydraulic piston 14. Acting, the needle valve 13 closes the nozzle 9a, and the fuel injection from the nozzle 9a ends. At the end of fuel injection, the fuel injection rate falls rapidly, and the amount of black smoke (smoke) and particulates (particulate matter PM) emitted from the engine is reduced. The switching valve 5 for switching the injection rate is closed at the same time as the closing of the on-off valve 7 at the fuel injection end timing, or is closed when a predetermined time has elapsed from the fuel injection timing end timing.

As shown in FIG. 5, between the fuel chamber 12 of the injector 9 and the switching valve 5 for switching the injection rate, the high-pressure fuel in the fuel passage 10a passes through the orifice 6a of the fuel passage 10b to the low-pressure accumulator 4. As a result, the fuel pressure in the fuel passage 10a gradually decreases from the end of the fuel injection in each fuel injection cycle, and the pressure control is continued until the fuel injection in the next fuel injection cycle is started. Valve 3
The fuel pressure is reduced to the fuel pressure suitable for the low-pressure injection set by 4, and the injection rate in the next low-pressure injection becomes required.

Next, the warm-up control during idling operation before the engine cooling water temperature sufficiently rises in a low temperature state such as a cold region will be described with reference to FIGS. FIG. 6 is a flowchart showing a procedure of the warm-up control at the time of the idling operation before the engine cooling water temperature sufficiently rises. Electronic control unit 8
Determines whether the engine cooling water temperature Tw is higher than the set temperature Two (step S1), and when higher than the set temperature Two, shifts to the normal mode control (step S1).
2) Execute the control described above. Therefore, the low pressure accumulator 4
Is controlled to a normal pressure. The electronic control unit 8 determines in step S1 that the engine coolant temperature Tw is equal to the set temperature Tw.
When it is determined that it is lower than o, it is determined whether or not the engine is in a no-load state (step S3). When the determination is made, the process proceeds to the warm-up mode control (step S4). The determination of the no-load state is performed based on the accelerator opening. Electronic control unit 8
When the engine is in a load state, the normal mode control is performed prior to the warm-up mode control even when the engine coolant temperature Tw is equal to or lower than the set temperature Two.

When the electronic control unit 8 enters the warm-up mode control, the electronic control unit 8 reduces the pressure of the low-pressure accumulator 4 as shown in FIG.
The initial injection (low-pressure injection) is performed by increasing ΔPLCR from the pressure during the normal mode control in accordance with w, and the main injection (pressure) of the high-pressure accumulator 3 during the normal mode control is performed during the valve opening period of the injector 9. High pressure injection). That is, the injection pressure is increased only in the initial injection. The pressure increase of the low-pressure accumulator 4 is performed by controlling the duty ratio of the valve opening time of the control valve 34. FIG. 8 shows the relationship between the engine cooling water temperature Tw and the pressure increment ΔPLCR of the low-pressure accumulator 4.

As shown in FIG. 7, the valve opening timing of the injector 9 (the valve opening timing of the on-off valve 7) and the valve opening timing of the switching valve 5 are the same as in the normal mode control, and the initial injection amount of the injector 9 (low pressure The injection amount) increases according to the pressure increase (the pressure increase of the low-pressure accumulator 4) ΔPLCR from the initial injection pressure (the low-pressure injection pressure) during the normal mode control indicated by the dotted line. On the other hand, the fuel injection amount (total amount) during the warm-up mode control needs to be the same as the fuel injection amount (total amount) during the normal mode control. Therefore, the electronic control unit 8 includes the injector 9,
The closing time of the switching valve 5 is shortened by an amount corresponding to the increase in the initial injection amount (the closing timing of the injector 9 and the switching valve 5 is shortened). As a result, the fuel injection amount in the warm-up mode control in one fuel injection can be made equal to the fuel injection amount (indicated by a dotted line) in the normal mode control, and the injection waveform maintains a so-called boot shape. Injection can be performed, and an increase in combustion noise can be minimized.

Returning to FIG. 6, when the engine cooling water temperature Tw becomes higher than the set temperature Two in step S1 and the warm-up mode control ends, the electronic control unit 8 shifts to the normal mode control (step S2), and the low-pressure accumulator. The pressure increment ΔPLCT of the vessel 4 is set to zero. In this way, the white smoke discharged from the engine is reduced by increasing the pressure of the low-pressure accumulator 4 in accordance with the temperature of the engine cooling water at the time of warm-up until the temperature of the engine cooling water is sufficiently increased after the start in a low temperature state. can do. Further, only the pressure during the initial injection (low-pressure injection) increases and the pressure during the main injection (high-pressure injection) remains in the normal mode control, so that an increase in combustion noise can be minimized.

The electronic control unit 8 gives priority to load operation over idle operation and obtains an appropriate engine output according to the load. The electronic control unit 8 sets the accelerator pedal depression amount (accelerator opening) Acc detected by an accelerator opening sensor as an engine load detecting means to 0.
If not, that is, when the engine load is in the loaded state, the pressure increase control of the low-pressure accumulator 4 is prohibited regardless of the engine cooling water temperature Tw detected by the temperature sensor, and the injection pressure control according to the engine load state is performed. Do. This allows
Even during the warm-up mode control, it is possible to obtain an engine output corresponding to a loaded operation such as running.

[0032]

According to the present invention, according to the first aspect of the present invention,
By setting the low-pressure initial injection on the high-pressure side at the time of low-temperature start, white smoke discharged from the engine can be prevented, and combustion noise can be reduced by suppressing the maximum fuel pressure in one fuel injection. According to the second aspect of the present invention, by giving priority to a loaded operation such as running over idling, it is possible to obtain an appropriate engine output according to the loaded load.

According to the third aspect of the invention, the so-called boot-type injection is maintained as the fuel injection, so that an increase in combustion noise can be suppressed.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a pressure accumulating fuel injection device according to an embodiment of the present invention.

FIG. 2 is a schematic diagram showing connection between main elements of the fuel injection device shown in FIG. 1 and injectors of each cylinder of the engine.

FIG. 3 is a schematic view of the high-pressure fuel pump shown in FIG.

FIG. 4 is a diagram showing a change in the injection rate over time and a change in each open / close state of a switching valve for switching the injection rate and an on-off valve for controlling the injection timing in one fuel injection cycle performed in the normal mode. is there.

FIG. 5 is a diagram showing a change in fuel pressure in a fuel passage between an injector and a switching valve over time in one fuel injection cycle performed in a normal mode.

FIG. 6 is a flowchart showing a procedure of normal mode control and warm-up mode control at the time of engine start.

FIG. 7 is a timing chart showing a fuel injection waveform, driving of an injector and a switching valve, and pressure increase control of a low-pressure accumulator during warm-up mode control.

FIG. 8 is a map showing a relationship between an engine cooling water temperature and an increased pressure of a low-pressure accumulator.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 high-pressure fuel pump 3 high-pressure accumulator (first accumulator) 4 low-pressure accumulator (second accumulator) 3a pressure sensor (first fuel pressure detecting means) 4a pressure sensor (second fuel pressure detecting means) 5 high-pressure / low-pressure accumulator (Fuel injection rate) Switching valve (first control valve) for switching 7 On-off valve for controlling injection timing 8 Electronic control unit (control means) 9 Injector (fuel injection nozzle) 10a, 10b Fuel passage 20 Plunger pump (fuel pump) 34) Pressure control valve (second control valve) of low pressure accumulator

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (reference) F02M 45/00 F02M 45/00 A 47/00 47/00 EF term (reference) 3G066 AA07 AB02 AC02 AC09 AD04 AD07 BA22 BA24 BA26 CB07U CB09 CB11 CB12 CB15 CB16 CC14 CC67 CC70 CD26 CE12 CE22 DA04 DA06 DA09 DA11 DA16 DB04 DC04 DC09 DC14 DC18 3G084 AA01 BA14 BA15 CA02 DA10 DA39 EB24 EC03 FA18 FA20 3G301 HA02 MA26 MA23 MA01 MA23 MA02 MA26 NB02 NB06 NB11 ND41 NE01 NE23 PA17Z PB08Z PE01Z PE08Z PF03Z

Claims (3)

[Claims] 1. A first pressure accumulator for storing high-pressure fuel pressurized by a fuel pump, and a fuel connected to the first pressure accumulator via a fuel passage and injecting the supplied fuel into an engine combustion chamber. An injection nozzle, a first control valve for controlling discharge of high-pressure fuel in the first accumulator to the downstream side of the fuel passage, and storing the fuel at a lower pressure than the high-pressure fuel in the first accumulator to perform the first control. A second pressure accumulator connected to the fuel passage downstream of the valve via a branch passage, cooling water temperature detecting means for detecting a cooling water temperature of the engine, and an engine start time and a normal start time according to the cooling water temperature. At the time of the low temperature start, the fuel pressure is divided into two modes. At the time of the low temperature start, the fuel pressure of the second accumulator is set to a higher pressure side than at the time of the normal start, and only the fuel injection nozzle is opened to perform the initial injection. , The fuel injection nozzle opening timing It said in the middle of the first
And a fuel control means for performing a main injection by opening a control valve. 2. An engine load detecting means for detecting a load of the engine, wherein when the engine load is loaded by the engine load detecting means irrespective of an output of the cooling water temperature detecting means, the pressure of the initial injection is increased. The pressure accumulation type fuel injection control device according to claim 1, wherein the control is prohibited, and the injection pressure control is performed according to the engine load state. 3. The accumulator type fuel injection control device according to claim 1, wherein the fuel control means sets an initial injection pressure at the time of the low temperature start to be smaller than a main injection pressure.