JPS58152133A - Drive circuit for electromagnetic fuel injection valve - Google Patents

Abstract

PURPOSE:To control the bounce time to a minimum, to stabilize the movement of a needle valve and to extend the linearity of the amount of fuel injection up to the lower pulse zone by a method wherein the time required for a drive current to reach its peak is made larger than the time by which the opening of the fuel injection valve is delayed. CONSTITUTION:When the drive current is applied on an inner coil 1 from a drive circuit (a) through a terminal 6, a connector 7 is magnetized and a magnetic circuit including the connector 7, a housing 4 and a core 2 in said sequence is formed. Accordingly, a needle valve 3 is attracted to the end surface of the connector 7 against the force of a spring 9 but the stroke of the needle valve is regulated by a flange section 10 and a spacer 11 of the needle valve 3. In this case, the time Tip required for the drive current to reach its peak Ip from the time when the drive pulse is applied on the fuel injection valve is combined with an Ip current setting value peculiar to the fuel injection valve so that for example, Tip=1.2msec or the valve opening delay time To=1.1msec is obtained and the equation of Tip-To>=0.1msec is established.

Description

[Detailed Description of the Invention] This invention relates to a drive circuit for a type fuel injection valve, and is characterized in that a drive current value is set to an appropriate value for the movement of a needle valve inside the injection valve. shall be.

Conventional drive circuits for electromagnetic fuel injection valves have a peak current IP as the drive current, as shown in section 1.

It has a hold current Iit1i. The time Tip from when the drive power is applied to the injection valve until reaching Ip is determined by the resistance value and inductance of the injection valve and the peak current Ip value of the drive circuit.

The drawback of the conventional electromagnetic fuel injection valve and its drive circuit described above is that the resistance value and inductance inherent in the injection valve and the drive current peculiar to the movable circuit, particularly the peak current Ip setting value, are not properly matched.

This will be explained in Part 2.

When a drive pulse is applied to the injection valve now, the drive current will take time (suction time) T to reach the peak current Ip value.
However, the relation between the opening delay time To of the injection valve and the Txp and the t (Txp-To) value are not properly adjusted, and the needle valve inside the injection valve bounces after opening. Experiments have shown that in order to have a time TIO and further reduce the Two, it is necessary to have sufficient suction force after opening the valve and to have a sufficiently long Txp compared to the T. was confirmed.

However, the combination of the conventional injection valve and the drive circuit is
The bounce time Two may become excessive due to the temporary decrease in attractive force that occurs when moving from the peak current IP to the hold current IN due to this rounding. This adversely affects the linearity of the injection amount in the bass region.

The drive current obtained by the drive circuit of the present invention, especially the peak current IPK: The relationship between the time to reach Tip and the valve opening delay time To of the injection valve (σ1p−To) is set to an arbitrary value or more. It is characterized by being Experimental example
, (Ttp-To) 20.1 mH6, it was confirmed that the bounce time Two after opening the valve could be minimized.

In this way, by the combination of the resistance value specific to the injection valve and the nDIP value specific to the inductance drive circuit,
) δ, 1m5ec, the bounce time Tio can be minimized and the need μ
Valve behavior is stable and injection amount linearity is lower than before.
/, X111″1 to enlarge.

Next, one embodiment of the present invention will be explained with reference to the drawings.

As shown in FIG. 1, the electromagnetic fuel injection valve has nine nozzle holes 5 which are opened and closed at the tip of a nozzle body 4 that supports a needle valve 3 connected to a core 2 that is sucked in by energizing the carp μl. ing. Further, the drive circuit that drives the injection valve has a peak current of 1 as shown in FIG.
It is composed of a current IN on the p and negative currents. In this example, the resistance value and inductance of the injection valve are 2Ω, 4. j
llaIIt & the peak current Ip values are set by two people.

In the nine configurations described above, the drive current is supplied from the drive circuit to the terminal 6.
When the voltage is applied to the internal coil lvl through , the connector 7 is magnetized, and a magnetic circuit is formed in the order of connector flap → housing 8 → core 2 → connector 7.

Therefore, the needle valve 8 resists the spring 9 and the connector 7
However, the needle valve stroke is regulated by the flange portion 10 and spacer 11 formed on the needle valve 8. In other words, the time from when the driving current is applied until the flange portion 10 comes into contact with the spacer 11 is called the valve opening delay time ll1lTO, and the time during which the needle valve 3 is bouncing on the spacer 11 is called the bounce time Ti+o. The time Trp from when a drive pulse is applied to the injection valve to when it reaches Ip depends on the resistance value and inductance specific to the injection valve mentioned above and the I specific to the drive circuit.
With the combination of p setting value and consideration, TIP-1,2m5ec and the above 'To are obtained as Te1-1.1m5eci, (TIP
-To, iQ, and -ec can be secured. In addition, ag was performed by a base Fi experiment of 0-1 rnsec. This is shown in FIG.

As can be seen from FIG. 8, when (Txp-To) δ is 1 m5ec or more, the above-mentioned Two can also be kept constant and minimized.

As mentioned above, in this example, the resistance value, inductance, and Ip value of the drive circuit of the injection valve are set to 204.2w5H,
2m, but this matching is aiming for (Tip-To voice Kai 1m5ec.Furthermore, -To)>0.
In order to aim for 11m5ee, the resistance value, inductance, and Ip value of the drive circuit may be changed and matched within allowable ranges.

Tragically, it is conceivable that the resistance value of the injection valve decreases, the inductance increases, and the drive circuit Ip value increases with respect to this embodiment.

As mentioned above, the resistance value inductance specific to the injection valve is 20.4-2m1EI, and the Ip value specific to the drive circuit is 2
With this configuration, the difference (Tip-To) between the time it takes to reach Ip and the opening time To of the injector satisfies (TIP--≧O0-1). We determined through experiments that this is desirable.

Using this result, it is possible to further apply a sufficient suction force to the needle valve inside the injection valve after the injection valve is opened, thereby minimizing the bounce time Ti+o that occurs after the injection valve is opened, and the needle μ valve It has the excellent effect of stabilizing the behavior and extending the injection amount linearity to the low pass μ range.

[Brief explanation of the drawing]

Figure 81 is a cross-sectional view of the electromagnetic fuel injection valve, Figure M2 is a diagram showing the drive current waveform and needle valve behavior waveform, and Figure 3 is the (T
Relationship diagram between i p-To) and bounce time, 1... Carp ~, 2... Core, 3... Needle valve, 4... Nozzle body, 5... Nozzle hole, 6 - Terminal, ? ...Connector, 8-Housing, 9...Spring, 10...
7-Lange portion, 11-Spacer, T o... Valve opening delay time. Ttp 31 hour agent patent attorney Takashi Mabe

Claims (1)

[Scope of Claims] α) A drive circuit K having a peak current Ip and an umbrella current XM as a drive current for driving the electromagnetic fuel injection valve, and the time TiP until reaching the Ip is The drive circuit for the fuel injection valve, wherein the valve opening delay time To and Shi are also set to be long. (21) The relationship between the time TiP until the IPK is reached and the valve opening delay time TO of the injection valve is (T i p-To)
? O, 1m5e. The fuel injection valve drive circuit according to claim 1, wherein both the resistance and inductance inherent to the injection valve and the Ip value of the drive circuit are set to appropriate values so that the following is achieved.