JP2001349260A - Fuel heating control device of electromagnetic fuel injection valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently raise a temperature before injecting fuel injected from a fuel injection valve. SOLUTION: This fuel heating control device uses a two-coil type fuel injection valve having a control coil (C coil) for valve opening operation of a needle valve and a hold coil (H coil) for holding the needle valve in a valve opening state. To the control coil, current-carrying is started at valve opening operation time of the needle valve by an injection demand, and the current-carrying is stopped after transferring to the valve opening state. The hold coil is used not only for holding the valve opening state by carrying an electric current when there is the injection demand, and but also used for heating the fuel by heating of the coil by resuming the current-carrying after transferring to a valve closing state after stopping the current-carrying at valve closing operation time of the needle valve.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a fuel heating control device for an electromagnetic fuel injection valve in an internal combustion engine.

[0002]

2. Description of the Related Art In an internal combustion engine, when fuel injected and supplied from a fuel injection valve is vaporized before the start of combustion,
It is possible to reduce harmful components in exhaust gas typified by HC and smoke, and to improve fuel efficiency by improving combustion efficiency.

In view of the above, a method of heating fuel injected from a fuel injection valve before the fuel is injected from the fuel injection valve has been known. Specifically, an electromagnetic fuel injection valve has been known. Japanese Patent Application Laid-Open No. 9-264
As disclosed in Japanese Patent Publication No. 224, the current is supplied to the coil of the fuel injection valve during the invalid injection period that appears by outputting a fuel injection valve drive signal having a predetermined pulse width or less from the control means.
There has been known an apparatus in which fuel in a fuel injection valve is heated by heat generated by the coil.

On the other hand, as disclosed in Japanese Patent Application Laid-Open No. H11-148439, the responsiveness when the valve element is driven from the closed state to the valve opening direction is improved, and after opening the valve, the power consumption is stable with low power consumption. First electromagnetic drive means for opening the needle valve, and second electromagnetic drive means for holding the needle valve in an open state as an electromagnetic fuel injection valve having a structure capable of maintaining the valve open state. Have been proposed, and in general,
A control coil as first electromagnetic driving means;
This is realized as a two-coil fuel injection valve including a hold coil as an electromagnetic drive unit.

[0005]

However, in the conventional fuel heating control device for an electromagnetic fuel injection valve, when current is supplied to the coil of the fuel injection valve to generate heat, one energization is made shorter than the invalid injection period. In order to raise the fuel temperature without lifting the needle valve, it is necessary to repeat the energization shorter than the invalid injection period many times. There is a problem that the efficiency of the temperature rise is poor.

In view of such a conventional problem, the present invention provides a first electromagnetic drive means for opening a needle valve and a second electromagnetic drive means for holding the needle valve in an open state. An object of the present invention is to efficiently increase the fuel temperature by using an electromagnetic fuel injection valve having the following.

[0007]

Therefore, according to the first aspect of the present invention, as shown in FIG. 1, the first electromagnetic driving means for opening the needle valve and the needle valve are set to the open state. An electromagnetic fuel injection valve comprising: a second electromagnetic drive unit for holding; and a fuel heating energization control unit that energizes the needle valve when the needle valve is in a closed state. A fuel heating control device for the electromagnetic fuel injection valve is configured.

According to a second aspect of the present invention, in the direct injection type internal combustion engine, there is provided a means for detecting the in-cylinder pressure. Characterized in that an energization inhibiting means for inhibiting energization is provided.

According to a third aspect of the present invention, in a direct injection type internal combustion engine, there is provided a means for detecting an in-cylinder pressure and a means for detecting a fuel pressure supplied to a fuel injection valve. A current supply prohibiting means for prohibiting power supply in a closed state by the fuel heating power supply control means based on a pressure difference between the fuel pressure and the fuel pressure is provided.

In the invention according to claim 4, there is provided means for detecting a fuel temperature in the fuel injection valve, and based on the fuel temperature,
An energization prohibiting unit for prohibiting energization in the valve closed state by the fuel heating energization control unit is provided. still,
Instead of the energization inhibiting means, an energization time limiting means for limiting the energization time in the valve closed state by the fuel heating energization control means based on the fuel temperature may be provided (claim 5).

The invention according to claim 6 has means for detecting the temperature of the fuel in the fuel injection valve, and means for detecting the pressure of the fuel supplied to the fuel injection valve, based on the fuel temperature and the fuel pressure. An energization prohibiting unit for prohibiting energization in the valve closed state by the fuel heating energization control unit is provided. Instead of the energization inhibiting means, an energization time limiting means for limiting the energization time in the valve closed state by the fuel heating energization control means based on the fuel temperature and the fuel pressure may be provided. 7).

In the invention according to claim 8, there is provided means for detecting the temperature of the fuel injection valve body, and based on the temperature of the fuel injection valve body, energization in the valve closed state by the fuel heating energization control means is prohibited. It is characterized in that an energization inhibiting means is provided. Instead of the energization inhibiting means, an energization time limiting means for limiting the energization time in the valve closed state by the fuel heating energization control means based on the fuel injection valve body temperature may be provided. 9).

[0013] In the invention according to the tenth aspect, there is provided means for detecting an engine cooling water temperature, and based on the engine cooling water temperature,
An energization prohibiting unit for prohibiting energization in the valve closed state by the fuel heating energization control unit is provided. still,
Instead of this energization inhibiting means, based on the engine cooling water temperature,
An energization time limiter for limiting the energization time in the valve closed state by the fuel heating energization control means may be provided.

According to a twelfth aspect of the invention, there is provided a multi-cylinder internal combustion engine having a fuel injection valve for each cylinder and supplying fuel to the fuel injection valves in a predetermined order through a series of fuel passages.
The present invention is characterized in that energization time limiting means for limiting the energization time is provided such that the fuel injection valve on the downstream side of the fuel flow has a shorter energization time in the valve closed state by the fuel heating energization control means. .

[0015]

According to the first aspect of the present invention, the second electromagnetic drive means for holding the needle valve in the open state is energized when the needle valve is in the closed state, thereby injecting the fuel. When there is no request, sufficient electricity can be supplied without lifting the needle valve,
Since energization only needs to be stopped when the needle valve is closed, energization time can be extremely increased, and the temperature of the fuel in the fuel injection valve can be increased efficiently by increasing the amount of heat generated. Accordingly, the vaporization of the fuel injected from the fuel injection valve is promoted, and the exhaust performance, fuel efficiency, and the like can be improved.

According to the second aspect of the invention, the following effects can be obtained by prohibiting the energization in the valve closed state by the fuel heating energization control means based on the in-cylinder pressure. In the case of a direct injection type fuel injection valve, if the in-cylinder pressure increases in a state where the force in the valve closing direction is weakened by energization in the closed state, the in-cylinder pressure acts in the valve opening direction, The valve opens other than at the time of injection request, and the working gas in the cylinder flows into the fuel injection valve. There is a possibility that a problem such as deterioration of reliability represented by breakage or clogging inside the fuel injection valve may occur, but based on the in-cylinder pressure, specifically, when the in-cylinder pressure is a predetermined value or more, By prohibiting energization in the valve closed state, the above-described problem can be prevented.

According to the third aspect of the invention, the energization in the valve closed state by the fuel heating energization control means is prohibited based on the pressure difference between the in-cylinder pressure and the fuel pressure. The effect is obtained. In the case of a direct injection type fuel injection valve, the force in the valve closing direction is weakened by energizing in the closed state,
When the in-cylinder pressure increases, the in-cylinder pressure acts in the valve opening direction, and when the fuel pressure decreases, the force in the valve closing direction further weakens. Although the above-mentioned problem may occur, it is necessary to prohibit energization in the valve-closed state based on the differential pressure between the in-cylinder pressure and the fuel pressure, specifically, when the differential pressure is equal to or higher than a predetermined value. Thereby, the above problem can be more reliably prevented.

According to the fourth aspect of the invention, based on the fuel temperature in the fuel injection valve, specifically, when the fuel temperature is equal to or higher than a predetermined value (evaporation temperature), the fuel heating energization control means is used. By prohibiting energization in the closed state, fuel vaporization inside the fuel injection valve can be prevented, and deterioration in operability due to less fuel injection than the regulation caused by vaporization can be suppressed.

According to the fifth aspect of the present invention, the fuel temperature can be reduced more than necessary by limiting the energizing time in the valve closed state by the fuel heating energizing control means based on the fuel temperature. Therefore, the effect of claim 4 can be exhibited.

According to the sixth aspect of the invention, based on the fuel temperature and the fuel pressure, specifically, when the fuel temperature is equal to or higher than the vaporization temperature determined by the fuel pressure, the fuel heating energization control means closes the valve. By prohibiting the energization in the state, the vaporization of the fuel inside the fuel injection valve can be more reliably prevented, and the deterioration of the operability due to the fuel injection less than the regulation caused by the vaporization can be suppressed.

[0021] In addition, as in the invention according to claim 7, by restricting the energizing time in the valve closed state by the fuel heating energizing control means based on the fuel temperature and the fuel pressure, the fuel temperature can be increased more than necessary. The effect of claim 6 can be exhibited without lowering.

According to the eighth aspect of the invention, the temperature rise of the fuel injection valve main body is suppressed by prohibiting the energization in the closed state by the fuel heating energization control means based on the fuel injection valve main body temperature. In addition, deterioration of the reliability of the fuel injection valve can be suppressed.

[0023] Further, as in the ninth aspect of the invention, the energizing time in the valve closed state by the energizing control means for fuel heating is limited based on the temperature of the fuel injection valve main body, so that the fuel temperature can be increased more than necessary. The effect of claim 8 can be exhibited without lowering.

According to the tenth aspect of the present invention, the energization in the valve closed state by the fuel heating energization control means is prohibited based on the temperature of the engine cooling water. In addition, since the temperature in the combustion chamber is high, and even if the fuel is heated, the effect of improving the exhaust performance and the like is lost, the power consumption under such conditions can be reduced, and the deterioration of fuel efficiency can be suppressed.

Further, the fuel temperature can be reduced more than necessary by limiting the energizing time in the valve closed state by the fuel heating energizing control means based on the engine coolant temperature. The effect of claim 10 can be exerted without causing this.

According to the twelfth aspect of the present invention, when fuel is supplied to the fuel injection valves of each cylinder in a predetermined order through a series of fuel passages, the more downstream the fuel flow is, the more the fuel flows. By shortening the energizing time in the valve closed state by the energizing control means for heating, the fuel temperature rises more in the fuel injection valve on the downstream side of the fuel flow, the combustion state changes for each cylinder, It is possible to suppress the deterioration of the performance and to eliminate the variation between the cylinders.

[0027]

Embodiments of the present invention will be described below in detail with reference to the drawings. In the following embodiments, a first coil (hereinafter, referred to as a control coil, referred to as a C coil in the drawing) as first electromagnetic driving means for opening a needle valve, and opening the needle valve The present invention is applied to a two-coil type fuel injection valve including a second coil (hereinafter, referred to as a hold coil, which is referred to as an H coil in the drawing) as second electromagnetic driving means for maintaining the state. .

FIG. 2 shows a structural diagram of a two-coil fuel injection valve. In the two-coil fuel injection valve 1, a needle valve (plunger) 4 is housed in the main body 2 so as to be opposed to the seat portion of the injection hole 3 at the tip of the main body 2, and the needle valve 4 acts on its flange portion 4 a. The return spring 5 is urged in the valve closing direction. A control coil 6 and a hold coil 7 are provided to generate an electromagnetic attraction in the valve opening direction for the needle valve 4.

On the other hand, the fuel entering from the fuel inlet 8 at the base end of the main body 2 flows through the fuel passage 9 and is guided to the fuel reservoir 10 around the needle valve 4. In a state where neither the control coil 6 nor the hold coil 7 is energized, the needle valve 4 is pressed against the seat portion of the injection hole 3 by the return spring 5 and is in a state where fuel is not injected (valve closed state). .

When energized, the control coil 6 attracts the flange portion 4a of the needle valve 4 by electromagnetic force, and lifts the needle valve 4 upward in the figure. As a result, the needle valve 4 separates from the injection hole 3, and the fuel in the fuel reservoir 10 is injected from the injection hole 3 to form a fuel spray F (valve open state).

Like the control coil 6, the hold coil 7 attracts the needle valve 4 by electromagnetic force, but the valve cannot be opened even if only the hold coil 7 is energized. Use to

That is, the control coil 6 has a coil structure that generates a force sufficient to open the valve, and the hold coil 7 has a coil structure that generates a force sufficient to maintain the valve open state. The former power is larger than the latter power, and the former power consumption is larger than the latter power consumption.

FIG. 3 shows a time chart of a conventional energization control for fuel injection control. When an injection request is generated based on the fuel injection request signal, energization of the control coil 6 is started to shift to the valve open state. At substantially the same time, the power supply to the hold coil 7 is started. Then, after a lapse of time during which the needle valve 4 can be completely opened, the power supply to the control coil 6 is stopped. On the other hand, the energization of the hold coil 7 is continued, and the needle valve 4 is held in the open state. When there is no more injection request, the power supply to the hold coil 7 is stopped and the state is shifted to the valve closed state. This is because, as described above, the electromagnetic attraction generated by the control coil 6 is large, and it takes time for the magnetic force to disappear due to the magnetic characteristics even when the energization is stopped, and it takes time for the valve to be closed. This is also to solve the problem that power consumption is large and fuel consumption is increased.

FIG. 4 is a time chart of the power supply control of the present invention (first embodiment) for fuel injection control and fuel heating control. Even when there is no injection request, power is supplied to the hold coil 7 to heat the fuel by the heat generated by the coil 7. As described above, if only the hold coil 7 is energized, the valve is not opened, and no fuel is injected. When an injection request is generated, the control coil 6 is energized to shift to the valve open state. After a lapse of time that allows the needle valve 4 to be completely opened, the control coil 6
The power supply to the valve is stopped, and the valve is held open by the hold coil 7. When there is no more injection request, the power supply to the hold coil 7 is stopped and the state is shifted to the valve closed state. Then, after a lapse of time during which the needle valve 4 can be completely closed, the supply of electricity to the hold coil 7 is started again. As described above, the valve is not opened even if the hold coil 7 is energized again. With this control, the energization time of the hold coil 7 is significantly longer than that of the conventional control, and the fuel temperature rise effect is excellent.

FIG. 5 is a flowchart of an energization control routine for energization control according to the present invention (first embodiment), which is executed every predetermined unit time or every unit crank angle. In step 1 (referred to as S1 in the figure, the same applies hereinafter), it is determined whether or not there is an injection request based on the fuel injection request signal.

If there is an injection request, the routine proceeds to step 2, where it is determined whether or not the previous injection request was made. Step 2
If there is no previous injection request, it means that there has been a change from no injection request to present (at the start of injection), and the process proceeds to step 3.

In step 3, the control coil 6 is energized to shift to an open state.
Then, the first timer for measuring the energization time of the control coil 6 is reset to 0 and started.

Then, proceeding to step 5, if the power supply to the hold coil 7 is not performed, the power supply to the hold coil 7 is started, and this routine ends. Basically, since the energization has been started in step 13 described later, the energized state is maintained.

If it is determined in step 2 that there has been a previous injection request, the control coil 6 has already been energized, so the flow proceeds to step 6 where the first timer is set to a predetermined value T1 (complete valve open state). It is determined whether or not it is equal to or longer than the time that can be shifted to.

If the value of the first timer is less than the predetermined value T1, this routine is terminated while the power supply to the control coil 6 is continued. When the first timer reaches the predetermined value T1,
Proceeding to step 7, the energization of the control coil 6 is stopped. If the energization has already been stopped, the non-energized state is maintained, and this routine ends. Therefore, the valve open state is maintained by continuing the energization of only the hold coil 7.

If there is no injection request, the routine proceeds to step 8, where it is determined whether or not there was no injection request last time. Step 8
In the determination of the above, the case where there is a previous injection request is a case where there has been a change from the presence of the injection request to the absence thereof (when the injection is stopped), and the routine proceeds to step 9.

In step 9, the power supply to the hold coil 7 is stopped to shift to the valve closed state.
Second measurement for measuring the power supply stop time of the hold coil 7
The timer is reset to 0, started, and this routine ends.

If it is determined in step 8 that there is no previous injection request, the energization of the hold coil 7 has already been stopped, so the routine proceeds to step 11, where the second timer sets the predetermined value T2 (completely closed state). It is determined whether or not it is equal to or longer than the time that can be shifted to.

If the value of the second timer is less than the predetermined value T2, this routine is terminated while the power supply to the hold coil 7 is stopped. If the second timer has reached the predetermined value T2, the routine proceeds to step 13, where the hold coil 7
If you have already energized and have already energized,
The current supply state is maintained, and this routine ends. By energizing only the hold coil 7 in such a closed state, the fuel can be heated without opening the valve. Here, in particular, the step 13 corresponds to the fuel heating power supply control means.

As described above, by energizing the hold coil 7 for holding the needle valve 4 in the open state when the needle valve 4 is in the closed state, in other words, closing the needle valve 4 By stopping the energization only during the valve operation, the energization time can be made extremely long without lifting the needle valve 4 when there is no injection request, and the amount of heat generated in the fuel injection valve 1 can be increased by increasing the heat generation amount. The temperature can be raised efficiently, thereby promoting the vaporization of the fuel injected from the fuel injection valve 1 and improving the exhaust performance and fuel efficiency.

Next, an embodiment in which the energization of the hold coil 7 in the valve closed state is prohibited or the energization time is limited under various conditions will be described. FIG. 6 shows a system configuration in the case of performing fuel heating control using a two-coil fuel injection valve 1 in a direct injection type internal combustion engine, particularly a direct injection spark ignition type internal combustion engine.

Therefore, an internal combustion engine (hereinafter referred to as an engine)
A two-coil fuel injection valve 1 is mounted so as to inject fuel directly into the combustion chamber 21 of the fuel injection valve 20. The fuel in the fuel tank 22 is supplied to the fuel injection valve 1 by a fuel pump 23 through a fuel passage 24. And pressurized supply. In addition, 25 is a throttle valve, 26 is an intake manifold, 27 is an intake valve, and 28 is a spark plug.

The energization of the control coil 6 and the hold coil 7 of the two-coil fuel injection valve 1 is controlled by the control unit 30.
The signal 0 is input from various sensors.

The crank angle sensor 31 outputs a signal for each unit crank angle and for each reference crank angle. The crank angle sensor 31 can detect the crank angle position from the signal and can calculate the engine speed Ne.

The intake pressure sensor 32 is connected to the intake manifold 2
6 and is attached to the collector section to detect the intake pressure Pa. The throttle sensor 33 is attached to the throttle valve 25 and detects the opening TVO.

The water temperature sensor 34 faces the water jacket of the engine 20 and detects a cooling water temperature Tw. The in-cylinder pressure sensor 35 is formed and attached in the shape of a washer of the ignition plug 28, and detects in-cylinder pressure (combustion chamber pressure) Pc by a piezoelectric element.

The fuel pressure sensor 36 detects the fuel pressure Pf supplied to the fuel injection valve 1 in the fuel passage 24 to the fuel injection valve 1 (or in the fuel injection valve 1). The fuel temperature sensor 37 detects a fuel temperature Tf in the fuel injection valve 1.

The fuel injection valve main body temperature sensor 38 detects a main body temperature (preferably a coil temperature) Tb of the fuel injection valve 1. These sensors 31 to 38 are selectively mounted and used according to the necessity in the following embodiments.

The second embodiment is based on the in-cylinder pressure (combustion chamber pressure) when performing fuel heating control using the two-coil fuel injection valve 1 in the in-cylinder direct injection type engine as described above. More preferably, based on the in-cylinder pressure and the fuel pressure, when the pressure difference between the in-cylinder pressure and the fuel pressure is equal to or greater than a predetermined value, the fuel heating control is stopped.

That is, when the in-cylinder pressure increases due to the compression pressure and the combustion pressure, a force acts to open the fuel injection valve 1. Further, when the fuel pressure decreases, the force for closing the valve becomes weak. When the fuel heating control is not performed, in consideration of a rise in in-cylinder pressure and a decrease in fuel pressure, the fuel injection valve 1 is not opened when there is no injection request.
Since the load of the return spring 5 is set, the fuel injection valve 1 does not open when there is no injection request. However, when performing the fuel heating control, when there is no injection request, the hold coil 7 is energized to generate a force in the valve opening direction, so that the in-cylinder pressure increases and the fuel pressure decreases. This causes a problem that the valve is easily opened. To solve this problem, the hold coil 7 in the valve closed state is determined based on the in-cylinder pressure and the fuel pressure.
The prohibition of power supply to the head is prohibited.

In the energization inhibition control, in the system configuration shown in FIG. 6, in-cylinder pressure sensor 35 as in-cylinder pressure detection means and fuel pressure sensor 36 as fuel pressure detection means are provided.
Is used.

FIG. 7 is a flow chart of an energization control routine when energization inhibition control is performed. The difference from the flow of FIG. 5 is that after the injection request is eliminated, the energization of the hold coil 7 is stopped, and the state is shifted to the valve-closed state, the second timer reaches the predetermined value T2. Proceeding to step 12, it is determined whether or not the energization prohibition flag is set to 1. If the energization prohibition flag is 0, the process proceeds to step 13 to start energization of the hold coil 7 (after starting). If the energization prohibition flag = 1, the process proceeds to step 14 and the energization of the hold coil 7 is stopped (if the energization is stopped, the non-energization state is maintained).

FIG. 8 is a flowchart of a power-supply prohibition routine according to the second embodiment, which is executed, for example, at every crank angle of 1 °. In step 21, it is determined whether there is an injection request.

If there is no injection request, the routine proceeds to step 22, where the in-cylinder pressure (combustion chamber pressure) Pc detected by the in-cylinder pressure sensor 35 is read. In step 23, the fuel pressure Pf detected by the fuel pressure sensor 36 is read.

Then, in step 24, it is determined whether or not the difference (Pc-C * Pf) between the in-cylinder pressure Pc and the correction coefficient C * fuel pressure Pf is equal to or greater than a predetermined value. Here, C is the degree of the effect of opening and closing the injection valve due to a difference in the pressure receiving area when the in-cylinder pressure Pc and the fuel pressure Pf are applied to the needle valve 4, and the degree of the influence of the in-cylinder pressure Pc and the fuel pressure. This is a coefficient for correcting the difference with the pressure Pf.

If Pc−C × Pf ≧ predetermined value, it is determined that there is a possibility that the valve will be opened, and the routine proceeds to step 25, where the energization inhibition flag is set to 1. This prohibits the energization of the hold coil 7 in the valve closed state in the flow of FIG. Therefore, steps 24 and 25 in FIG. 8 and steps 12 and 14 in FIG.

If Pc−C × Pf <predetermined value, there is no possibility that the valve will open, so the routine proceeds to step 26, where the energization inhibition flag is reset to 0. As a result, power is supplied to the hold coil 7 in the valve closed state in the flow of FIG.

If there is an injection request, the valve is in the open state, so the routine proceeds to step 26, where the energization inhibition flag is reset to zero. FIG. 9 shows the change in the in-cylinder pressure during the compression stroke to the explosion stroke and the energization pattern to the control coil and the hold coil. Assuming that the fuel pressure is constant, in the case of (a), Since the in-cylinder pressure does not exceed the specified value, energization is not prohibited, but in the case of (b),
Since the in-cylinder pressure temporarily exceeds the specified value,
Energization is prohibited.

Next, a third embodiment will be described. In the above-described second embodiment, for example, the in-cylinder pressure is determined in real time for each crank angle of 1 °, but in the third embodiment, the maximum in-cylinder pressure is detected for each cycle, and this is used. The current supply prohibition control is performed.

FIG. 10 is a flowchart of an energization prohibition routine according to the third embodiment, which is executed every cycle. In step 31, the maximum in-cylinder pressure Pcmax in one cycle, which is calculated separately, is read.

In step 32, the fuel pressure Pf is read. In step 33, the difference between the maximum in-cylinder pressure Pcmax and the correction coefficient C × fuel pressure Pf (Pcmax−C × P
It is determined whether or not f) is equal to or greater than a predetermined value.

If Pcmax-C.times.Pf.gtoreq.predetermined value, it is determined that there is a possibility that the valve will be opened, and the routine proceeds to step 34, where the energization inhibition flag is set to 1. This prohibits the energization of the hold coil 7 in the valve closed state in the flow of FIG. In this case, steps 33 and 3 in FIG.
The portion 4 and the portions of steps 12 and 14 in FIG.

If Pcmax−C × Pf <predetermined value, there is no possibility that the valve will be opened.
The energization prohibition flag is reset to 0. As a result, FIG.
In the flow, the power is supplied to the hold coil 7 in the closed state.

Therefore, as shown in the time chart of FIG. 11, for example, when the accelerator opening is increased and the fuel pressure is constant, if the maximum in-cylinder pressure in one cycle exceeds a specified value, the following occurs. In the cycle, the energization prohibition flag is set to 1, and energization of the hold coil 7 in the valve closed state is prohibited. When the maximum in-cylinder pressure in one cycle falls within the specified value, the energization prohibition flag is reset to 0 from the next cycle, and energization to the hold coil 7 in the valve closed state is restarted. .

In the second embodiment and the third embodiment,
Although the in-cylinder pressure sensor 35 for directly detecting the in-cylinder pressure Pc is provided as the in-cylinder pressure detecting means, the in-cylinder pressure detecting means is not limited to this, and indirectly detects (predicts) the in-cylinder pressure. It may be something.

As a method of estimating the in-cylinder pressure, in the system configuration of FIG. 6, a crank angle sensor 31 for detecting a crank angle position and an intake pressure sensor 32 for detecting an intake pressure Pa are used, and Intake pressure P during open period
From a, a method of predicting the in-cylinder pressure Pc during combustion can be cited.

In this case, the intake pressure Pa can be directly detected by the intake pressure sensor 32, or can be predicted from the throttle opening TVO using the throttle sensor 33. Further, the opening period of the intake valve 27 may be directly detected by an intake valve lift sensor (not shown) instead of the crank angle position.

Since the fuel pressure Pf is basically controlled by a mechanical or electric fuel pressure constant control valve, the fuel pressure Pf is regarded as constant, and is determined based on only the in-cylinder pressure Pc. Alternatively, the fuel pressure sensor 36 may be omitted.

Further, in the second and third embodiments, the differential pressure is calculated by subtracting the fuel pressure Pf (the product of this and the correction coefficient C) from the in-cylinder pressures Pc and Pcmax. The differential pressure may be calculated based on the ratio between Pcmax and the fuel pressure (or a value after the correction).

Next, a fourth embodiment will be described. 4th
The embodiment is based on the fuel temperature in the fuel injection valve 1, and more desirably, based on the fuel temperature in the fuel injection valve 1 and the fuel pressure supplied to the fuel injection valve 1, The power supply to the hold coil 7 is prohibited, or the power supply time to the hold coil 7 in the valve closed state is limited.

That is, at a certain fuel pressure, when the fuel temperature exceeds a certain fuel temperature, the fuel is vaporized inside the fuel injection valve 1, thereby reducing the fuel injection amount and deteriorating the operability.

Therefore, in such a situation, energization of the hold coil 7 in the valve closed state is prohibited, or the energization time is limited to suppress a rise in the temperature of the fuel.
This prevents the fuel from evaporating inside.

For such control, a fuel temperature sensor 37 as a fuel temperature detecting means in the system configuration of FIG.
And a fuel pressure sensor 36 as fuel pressure detecting means. Although FIG. 6 shows an example of a direct injection type engine, the present embodiment and the subsequent embodiments are also applicable to a case where the fuel injection valve 1 is attached to an intake system.

FIG. 12 is a flowchart of a power-supply prohibition routine according to the fourth embodiment. In step 41, the fuel temperature Tf in the fuel injector 1 detected by the fuel temperature sensor 37 is read.

In step 42, the fuel pressure Pf detected by the fuel pressure sensor 36 is read. In step 43, the fuel vaporization temperature Te is calculated from the fuel pressure Pf by referring to a table.

In step 44, the fuel temperature Tf is compared with the fuel vaporization temperature Te, and the fuel temperature Tf is compared with the fuel vaporization temperature Te.
It is determined whether or not this is the case. If Tf ≧ Te, the process proceeds to step 45, in which the energization prohibition flag is set to 1 or the energization stop time T2 during the valve closing operation is set to a predetermined value on the large side in order to limit the energization time in the valve closed state. Set.

When the energization inhibition flag is set to 1,
According to the flow of FIG. 7, energization (fuel heating control) to the hold coil 7 in the valve closed state is prohibited. Power supply stop time T2
Is set to a predetermined value on the large side, the time T2 from when the energization to the hold coil 7 is stopped during the valve closing operation to when the energization is resumed in the flow of FIG.
The energization time (heating time) in the valve closed state can be shortened. Therefore, this part corresponds to the energization inhibiting means or the energization time limiting means.

If Tf <Te, the routine proceeds to step 46, where the energization prohibition flag is reset to 0, or the energization stop time T2 during the valve closing operation is set to a smaller value in order to maximize the energization time in the valve closed state. Is set to a predetermined value.

When the energization inhibition flag is reset to 0, the hold coil 7 in the valve closed state is set according to the flow of FIG.
(Fuel heating control). When the energization stop time T2 is set to the predetermined value on the small side, the time T2 from when the energization to the hold coil 7 is stopped during the valve closing operation in the flow of FIG. Therefore, the energization time (heating time) in the valve closed state can be lengthened.

In this embodiment, the fuel temperature sensor 37 for directly detecting the fuel temperature Tf in the fuel injection valve 1 is provided as the fuel temperature detecting means. However, the fuel temperature detecting means is not limited to this. , Fuel temperature Tf, engine speed Ne, throttle opening TVO, engine coolant temperature T
The information may be detected (predicted) indirectly from w or the like.

Since the fuel pressure Pf is basically controlled by a mechanical or electric fuel pressure constant control valve, the fuel pressure Pf is regarded as constant, and the fuel vaporization temperature Te is set. The sensor 36 may be omitted.

When the power supply time is limited, the power supply time (power supply stop time T2) can be continuously changed according to the difference between the fuel temperature Tf and the vaporization temperature Te.

Next, a fifth embodiment will be described. Fifth
In the embodiment, based on the temperature of the main body of the fuel injection valve 1, energization to the hold coil 7 in the closed state is prohibited, or the energization time to the hold coil 7 in the closed state is limited. is there.

That is, when the temperature of the main body of the fuel injection valve 1 exceeds a certain temperature, it may not be possible to secure the reliability of the coil components. Further, in the case of the direct injection type engine, combustion substances accumulate in the injection hole 3 of the fuel injection valve 1 and the fuel injection amount becomes smaller than a specified value, and the spray form changes.

Therefore, in order to suppress these, the energization is controlled by the temperature of the main body of the fuel injection valve 1. For such control, the fuel injection valve main body temperature sensor 38 as the fuel injection valve main body temperature detecting means in the system configuration of FIG.
Is used.

FIG. 13 is a flowchart of a power-supply prohibition routine according to the fifth embodiment. In step 51, the fuel injection valve 1 detected by the fuel injection valve body temperature sensor 38
Is read.

In step 52, the main body temperature Tb is compared with a predetermined value to determine whether or not the main body temperature Tb is higher than a predetermined value. If Tb ≧ predetermined value, the routine proceeds to step 53, where the energization inhibition flag is set to 1 or the energization stop time T2 is set to a predetermined value on the large side in order to limit the energization time in the valve closed state.

When the energization inhibition flag is set to 1,
According to the flow of FIG. 7, energization of the hold coil 7 in the valve closed state is prohibited. When the energization stop time T2 is set to a predetermined value on the large side, the time T2 from when the energization to the hold coil 7 is stopped at the time of the valve closing operation in the flow of FIG. Therefore, the energization time in the valve closed state can be shortened. Therefore, this part corresponds to the energization inhibiting means or the energization time limiting means.

If Tb <predetermined value, the routine proceeds to step 54, where the energization prohibition flag is reset to 0, or the energization stop time T2 is set to a small predetermined value in order to maximize the energization time in the valve closed state. Set.

When the energization prohibition flag is reset to 0, the hold coil 7 in the valve closed state is set according to the flow of FIG.
Will be energized. When the energization stop time T2 is set to the predetermined value on the small side, the time T2 from when the energization to the hold coil 7 is stopped during the valve closing operation in the flow of FIG. Therefore, the energization time in the valve closed state can be lengthened.

In this embodiment, the fuel injection valve main body temperature sensor 38 for directly detecting the main body temperature Tb of the fuel injection valve 1 is provided as the fuel injection valve main body temperature detecting means.
The fuel injection valve main body temperature detecting means is not limited to this.
The body temperature Tb may be indirectly detected (predicted) from the engine speed Ne, the throttle opening TVO, the engine coolant temperature Tw, and the like. When the energization time is limited, the energization time (energization stop time T2) may be continuously changed according to the fuel injection valve body temperature Tb.

Next, a sixth embodiment will be described. Sixth
In the present embodiment, energization to the hold coil 7 in the valve closed state is prohibited, or the energization time to the hold coil 7 in the valve closed state is limited based on the engine coolant temperature.

That is, when the engine coolant temperature is high,
Since the intake air temperature and the combustion chamber temperature are high, even if the fuel is heated, the effect of improving the exhaust performance and the like is lost. Therefore, in order to reduce power consumption, improve fuel efficiency and reduce harmful exhaust components, when the temperature of the engine cooling water is higher than the specified temperature, energization of the hold coil 7 in the valve closed state is restricted or the energization time is limited. You do it.

For such control, a water temperature sensor 34 as a cooling water temperature detecting means in the system configuration of FIG. 6 is used. FIG. 14 is a flowchart of an energization prohibition routine according to the sixth embodiment.

In step 61, the cooling water temperature Tw detected by the water temperature sensor 34 is read. In step 62, the cooling water temperature Tw is compared with a predetermined value to determine the cooling water temperature Tw.
Is greater than or equal to a predetermined value.

If Tw ≧ predetermined value, the process proceeds to step 63, in which the energization inhibition flag is set to 1 or the energization stop time T2 is set to a predetermined value on the large side in order to limit the energization time in the valve closed state. I do.

When the energization inhibition flag is set to 1,
According to the flow of FIG. 7, energization of the hold coil 7 in the valve closed state is prohibited. When the energization stop time T2 is set to a predetermined value on the large side, the time T2 from when the energization to the hold coil 7 is stopped at the time of the valve closing operation in the flow of FIG. Therefore, the energization time in the valve closed state can be shortened. Therefore, this part corresponds to the energization inhibiting means or the energization time limiting means. When the energization time is limited, the energization time (energization stop time T2) may be continuously changed according to the engine coolant temperature Tw.

If Tw <predetermined value, the routine proceeds to step 64, where the energization prohibition flag is reset to 0, or the energization stop time T2 is set to a small predetermined value in order to maximize the energization time in the valve closed state. Set.

When the energization inhibition flag is reset to 0, the hold coil 7 in the valve closed state is set according to the flow of FIG.
Will be energized. When the energization stop time T2 is set to the predetermined value on the small side, the time T2 from when the energization to the hold coil 7 is stopped during the valve closing operation in the flow of FIG. Therefore, the energization time in the valve closed state can be lengthened.

Next, a seventh embodiment will be described. Seventh
The embodiment includes a fuel injection valve for each cylinder, in a multi-cylinder engine that supplies fuel to each fuel injection valve in a predetermined order through a series of fuel passages, the more the fuel injection valve on the downstream side of the fuel flow, The current supply time to the hold coil 7 in the valve closed state is limited to a short time.

That is, as shown in FIG. 15 for convenience, the fuel in the fuel tank 22 is pressurized by the fuel pump 23, and the fuel in each cylinder (# 1 , # 2) are supplied to the fuel injection valves 1A, 1B and pass through the vicinity of the inside of the fuel injection valve 1A on the way, and the fuel flow is higher than that of the # 1 cylinder fuel injection valve 1A on the upstream side. During the fuel heating control, the fuel injection valve 1B of the # 2 cylinder in which the flow of the fuel flows downstream includes a part of the fuel heated by the fuel injection valve 1A on the upstream side, so that the fuel temperature further increases. . Thereby, the upstream cylinder (#
There is a difference in combustion state between 1) and the downstream cylinder (# 2), which causes a problem that the operability is deteriorated.

Therefore, in order to suppress this, the energization time limiting means reduces the flow of fuel to the downstream side of the fuel injection valve, that is, the time of energization to the hold coil 7 of the fuel injection valve 1A of the # 1 cylinder. , # 2 cylinder fuel injection valve 1B
Therefore, the current supply time to the hold coil 7 is limited to a short time.

Specifically, the energization stop time T2 during the valve closing operation in the flow of FIG. 5 or FIG.
While the energization stop time T2 of the hold coil 7 of the one-cylinder fuel injection valve 1A is shortened, the energization stop time T2 of the hold coil 7 of the # 2 cylinder fuel injection valve 2A is lengthened.

As a result, as shown in the time chart of FIG. 16, the power supply stop time of the hold coil 7 of the fuel injection valve 1B of the # 2 cylinder on the fuel downstream side where the fuel temperature tends to increase is lengthened, in other words, the power supply time , The temperature rise more than necessary can be suppressed, and the fuel temperature of the fuel injection valve of each cylinder can be made uniform.

[Brief description of the drawings]

FIG. 1 is a functional block diagram showing a configuration of the present invention.

FIG. 2 is a structural diagram of a two-coil fuel injector showing an embodiment of the present invention.

FIG. 3 is a time chart of a conventional energization control.

FIG. 4 is a time chart of energization control according to the present invention (first embodiment).

FIG. 5 is a flowchart of an energization control routine according to the first embodiment;

FIG. 6 is a system diagram of an engine showing an embodiment of the present invention.

FIG. 7 is a flowchart of an energization control routine according to a second embodiment.

FIG. 8 is a flowchart of an energization prohibition routine according to a second embodiment.

FIG. 9 is a time chart of the second embodiment.

FIG. 10 is a flowchart of an energization prohibition routine according to a third embodiment.

FIG. 11 is a time chart of the third embodiment.

FIG. 12 is a flowchart of an energization prohibition routine according to a fourth embodiment.

FIG. 13 is a flowchart of an energization prohibition routine according to a fifth embodiment.

FIG. 14 is a flowchart of an energization prohibition routine according to a sixth embodiment.

FIG. 15 is a schematic view of a fuel supply system according to a seventh embodiment.

FIG. 16 is a time chart of the seventh embodiment.

[Explanation of symbols]

 1, 1A, 1B 2 coil type fuel injection valve 2 main body 3 injection hole 4 needle valve 5 return spring 6 control coil 7 hold coil 20 engine 21 combustion chamber 22 fuel tank 23 fuel pump 24 fuel passage 25 throttle valve 26 intake manifold 27 intake Valve 28 Spark plug 30 Control unit 31 Crank angle sensor 32 Intake pressure sensor 33 Throttle sensor 34 Water temperature sensor 35 In-cylinder pressure sensor 36 Fuel pressure sensor 37 Fuel temperature sensor 38 Fuel injector body temperature sensor

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F02M 31/12 321H 321J 321L (72) Inventor Takayuki Iwasaki 2 Takaracho, Kanagawa-ku, Yokohama-shi, Kanagawa Nissan Motor Co., Ltd. (72) Inventor Hiroko Nakajima 2 Takaracho, Kanagawa-ku, Yokohama-shi, Kanagawa Prefecture F-term (reference) 3G066 AA02 AB02 AD12 BA10 BA17 BA23 CC05U CC06U CD22 CD25 CD26 CE22 DC13 DC14 DC15 DC17 DC18

Claims (12)

[Claims] 1. An electromagnetic fuel injection valve comprising: a first electromagnetic driving means for opening a needle valve and a second electromagnetic driving means for holding the needle valve in an open state; A fuel heating control device for an electromagnetic fuel injection valve, comprising: an electromagnetic drive unit; and a fuel heating energization control unit that energizes when the needle valve is in a closed state. 2. An in-cylinder direct injection internal combustion engine, comprising means for detecting in-cylinder pressure, and energizing for inhibiting energization in a closed state by said fuel heating energization control means based on the in-cylinder pressure. 2. The fuel heating control device for an electromagnetic fuel injection valve according to claim 1, further comprising prohibiting means. 3. An in-cylinder direct injection type internal combustion engine having means for detecting in-cylinder pressure and means for detecting fuel pressure supplied to a fuel injection valve, wherein a difference between the in-cylinder pressure and the fuel pressure is provided. 2. A fuel heating control device for an electromagnetic fuel injection valve according to claim 1, further comprising an energization inhibiting means for inhibiting energization in a valve closed state by said fuel heating energization control means based on the pressure. 4. An electric power supply inhibiting means for detecting a fuel temperature in the fuel injection valve and for inhibiting an electric power supply in a closed state by the fuel heating electric power supply control means based on the fuel temperature. The fuel heating control device for an electromagnetic fuel injection valve according to claim 1, wherein: 5. An energizing time limiting means for limiting an energizing time in a closed state of said fuel heating energizing control means based on a fuel temperature in place of said energizing inhibiting means. A fuel heating control device for an electromagnetic fuel injection valve according to claim 4. 6. A fuel supply system comprising: means for detecting a fuel temperature in a fuel injection valve; and means for detecting a pressure of a fuel supplied to the fuel injection valve. 2. The fuel heating control device for an electromagnetic fuel injection valve according to claim 1, further comprising an energization inhibiting means for inhibiting energization in a closed state by the control means. 7. An electric power supply control apparatus according to claim 7, wherein said electric power supply control means includes an electric power supply time limiting means for restricting an electric power supply time in a closed state of said fuel heating electric power supply control means based on a fuel temperature and a fuel pressure. The fuel heating control device for an electromagnetic fuel injection valve according to claim 6, wherein 8. An electric power supply prohibiting means for detecting a fuel injection valve main body temperature, and for prohibiting energization in a closed state by the fuel heating electric power supply control means based on the fuel injection valve main body temperature. The fuel heating control device for an electromagnetic fuel injection valve according to claim 1, wherein: 9. A power supply time limiting means for limiting the power supply time in a closed state by said fuel heating power supply control means based on a fuel injection valve main body temperature in place of said power supply inhibition means. The fuel heating control device for an electromagnetic fuel injection valve according to claim 8. 10. An engine cooling water temperature detecting means,
2. A fuel heating control for an electromagnetic fuel injection valve according to claim 1, further comprising an energization inhibiting means for inhibiting energization in a closed state by said energizing control means for fuel heating based on an engine coolant temperature. apparatus. 11. An electric power supply control apparatus according to claim 7, wherein said electric power supply control means includes an electric power supply time restriction means for restricting an electric power supply time in a closed state of said fuel heating electric power supply control means based on an engine coolant temperature. The fuel heating control device for an electromagnetic fuel injection valve according to claim 10. 12. In a multi-cylinder internal combustion engine having a fuel injection valve for each cylinder and supplying fuel to the fuel injection valves in a predetermined order through a series of fuel passages, a fuel injection valve having a fuel flow downstream. 2. A power supply time limiter for limiting the power supply time so as to shorten the power supply time in the valve closed state by the fuel heating power supply control means.
A fuel heating control device for an electromagnetic fuel injection valve according to claim 1.