JPS6114448A - Fuel injection timing controller - Google Patents

Abstract

PURPOSE:To reduce the vibration and the noise while to purify the exhaust gas by providing a detector for detecting the excessive air rate in the exhaust gas of Diesel engine and means for correcting the target injection timing. CONSTITUTION:Detector groups 3 for detecting the operating condition of Diesel engine 1, means for calculating the target injection timing and means 7 for regulating the injection timing and provided. Furthermore, a detector 4 for detecting the excessive air rate in the exhaust gas from Diesel engine 1 and means 6 for correcting the target injection timing on the basis of the signal from the detector 4 are provided. Consequently, the vibration and the noise are reduced while the exhaust gas can be purified.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to electronic control of fuel injection timing in a diesel engine.

[Conventional technology]

Depending on the various operating conditions of the cell engine,
(1-] +1", Ill'i! AU ll, blasphemy J
+, and calculate the target injection timing and actual injection time IIJ' by -
・Is there a device that adjusts the fuel injection timing to achieve this?1. li
j has been proposed.

For example, in a device like this that controls a ζ distribution type injection pump, the engine rotation speed and fuel injection timing ``1'' determine the target injection timing, and then determine the actual injection timing obtained from the timer piston position of the injection pump. An example is to drive a solenoid valve for operating a timer valve 1-1 so that the injection timing coincides with the L1 target injection timing described in 1111. However, in this example, the engine is at high altitude. /, or if the air cleaner is clogged, I4. - If this occurs, the amount of intake air will decrease, the fire time will be delayed, vibration and noise of the engine, and 110 CO in the gas.
There was a problem of an increase in

In addition, in more advanced systems, the intake air t +
An example is to calculate +-y and correct the target injection timing based on this. In this case, two types of detectors, an intake pressure detector and an intake temperature detector, are required, which increases the cost. For example, JP-A-57-110730
The technology of the publication.

[Purpose of the invention]

The present invention has been made in view of the above problem, and by correcting the target injection timing based on a signal from an excess air ratio detector attached to the engine, it is possible to correct the target injection timing when the engine is operated at high altitudes or when the air filter is closed. Optimal injection timing control is performed even in the event of a blockage, reducing vibration, noise, and HC in exhaust gas.
An object of the present invention is to provide a fuel injection timing control device containing less -Co and the like.

[Structure of the invention]

To achieve this object, the present invention, as shown in FIG. 1, includes a group of operating state detectors 3 for detecting the operating state of the diesel engine 1, and a signal pair timing (actual injection timing) from the operating state detector group. In this fuel injection timing control device, the fuel injection timing control device includes an injection timing adjustment means 7 that adjusts the injection timing to match the This is a fuel*-1 injection timing control device characterized by comprising a target injection timing correction means 6 for correcting the target injection timing based on a signal from an excess rate detector 4.

〔Example〕

The present invention will be described below with reference to examples and drawings.

FIG. 2 is an overall configuration diagram of the fuel injection timing control device and related parts of the present invention. 1 is a diesel engine, 2 is a distribution type fuel injection pump, and 7 is an electro-hydraulic timer which corresponds to injection timing adjustment means and adjusts the fuel injection timing.

3Δ to 3D correspond to a group of operating state detectors, 3Δ is a rotational speed detector that detects the engine rotational speed, 3B is an injection amount detector that detects the fuel injection amount, and 3C is an actual injection that detects the fuel injection timing. The timing detector, 3D, is a water/!! detector that detects the temperature of the engine cooling water.

Reference numeral 4 denotes an excess air ratio detector that detects the excess air ratio in the exhaust gas of the engine, and specifically, a lean sensor or the like can be used.

10 is an input circuit that shapes the waveform of the signal from the rotation speed detector 3A, 11 is an input circuit that converts the signal from the excess air ratio detector 4 into a voltage signal, and 12 is an A/D that converts the analog signal into a diesel signal. It is a converter.

Reference numeral 13 corresponds to target injection timing calculation means and target injection timing correction means, and includes a CPU, ROM, and RAM.

It is a microcomputer consisting of a free-run timer, etc.

14 is based on the signal from the microcomputer 13,
This is an output circuit that outputs a drive signal to the timer 7, that is, a pulse having an appropriately adjusted duty ratio.

Next, the main components will be explained in detail below using FIGS. 3 to 8.

FIG. 3 is a cross-sectional view of the main parts of the timer 7 and the injection timing detector 3C. The timer piston 21 is connected to the roller ring 23 by a pinch, and when the timer piston 2I moves to the left in the figure, the roller ring 23 rotates in the clockwise rotation direction, and the fuel injection timing changes to the advance side.625 It is a Hoehn type fuel pump, and pressure is fed to a pressure chamber 28- in a drive shaft (not shown) of the injection pump. 26 is Oha Lona f
This valve is used to prevent the pressure in the pump internal pressure chamber 28 from rising excessively. The fuel in the pump internal pressure chamber 2) 3 is injected into the engine, and is also guided to the piston high pressure chamber 20 through the throttle.

Therefore, the position of the timer piston is determined by the balance between the pressure in the high pressure chamber 20 and the force of the timer piston return spring in the low pressure chamber 27, thereby determining the position of the L normal ring 23 and determining the injection timing. 22 as timer piston position adjustment means? fX Tel valve.

3C is an actual position detector of the timer piston as an actual injection timing detector, which utilizes the fact that the intufftance of the coil 32 increases as the core 3 fixed to the timer piston 21 approaches the coil 32, and is not shown in the figure. By inktance detection circuit? Convert to b pressure 1= sign. As a result, for example, when the roller link 23 reaches the slowest angle side, 3■ is outputted, and when it comes to the most advanced side, it outputs IV.

The rotation speed detector 3Δ and the input circuit 10 are shown in FIG. The rotation speed detector 3Δ consists of a float 33 that rotates in synchronization with the crankshaft of the engine 1 and a corresponding 'I'Ii magnetic pickup 34. From the electromagnetic pickup 34,
An alternating current signal Va as shown in FIG. 5 (al) is output, and when this alternating current signal Va is inputted to the input circuit 10, it is waveform-shaped and a pulse vb with a period Tn as shown in FIG. 5 fb. is output.

This detection signal is input to the microcomputer 13, and the microcomputer 13 determines the pulse interval l'? %” The engine speed can be calculated by counting Fn.

The main part of the injection amount detector 3B relative to the injection pump 2 (=1 position) is shown in FIG. The fuel injection amount is determined by the position of .Injection amount detector 3
By moving the core 3G fixed to the coil 37 in the coil 37, for example, when the fuel injection amount is zero, the spill ring is located at the uppermost position and the output voltage is 3■, and when the injection amount is at the maximum, the spill ring is located at the lowermost position and the output is It operates so that the voltage is 1■.

FIG. 7 shows the excess air ratio detector 4 and its input circuit 11, which are the gist of the present invention. In Figure 7, 24] is test 1
11 parts, is stabilized zirconia doped with yttrium oxide Y2O3 or inoterium oxide Yb2O3, and flows between the outer electrode 243 and the inner electrode 242 depending on the oxygen concentration in the atmosphere. This is a so-called limiting current method in which the lfi current is determined. Reference numeral 244 denotes an electrode, which connects the inner electrode 242 and the contact spring 245 as a good electrical conductor. 246 is a lead wire, 248 is an insulator, 2, i 7 +; I is an envelope, and the tip has a hole to allow engine exhaust gas to pass through, and a threaded part for attaching to the exhaust pipe. It is set up. Also, outside the detection unit 241 +J1. lI? The Li electrode 243 is connected to the envelope 2Δ7 by an insulator 248, a contact spring 245, and an electric conductor 244.
It is electrically connected to F,′. Next, its operation will be explained. Excess air ratio detector 4 detection unit 241
or installed in the exhaust pipe so that it is exposed to engine exhaust gas. Here, a current i shown in FIG. 8(a) flows depending on the amount of oxygen in the exhaust gas.

The characteristics showing this relationship are shown in Figure 8 (al).
The current l written in i'i'lJ is detected as a voltage by the current detection resistor R in the input circuit 11, and amplified by the amplifier, as shown in FIG.
Obtain the relationship between the voltage ■λ and the excess air ratio λ shown in b).

Next, the operation of the microcomputer 13 will be explained using FIGS. 9 to 11. FIG. 9 shows a flowchart of the main routine. First, in step 51, the actual injection timing TRE A L, the actual injection amount Q, and the excess air ratio λ are determined.
A signal such as JJd is input through the A/D converter 12 via U7.

In step 52, the final target injection timing TBASE is determined as a function of the engine speed NE and the actual injection amount Q using a calculation formula or map interpolation.

The relationship between ``I゛B A s r: and N + -2 and Q is shown in Figure 11 ta+.

In step 53, the injection timing correction term T (: o'ph
p is determined by a calculation formula or map interpolation as a function of the excess air ratio λ. T co (The relationship between 4p and λ is shown in FIG. 11(b) L:2.

In step 54, the final target injection timing T F i N is
ノ, (7r) mark blow! (・1 period” ['l A S
It is obtained as the sum of E and the injection timing correction term i''c o M I).

At step 55, the output duty ratio Dn reaches a maximum of 4%! 1.111, IJJT [mistake between ' i N and actual injection timing T RE Al-] is obtained by performing the calculation l) l +) as a function of 2 and the previous output duty ratio Dn-1.

At step 5G, the output duty ratio Dn is 111.
814.

- Steps 51 to 56 are executed repeatedly.

FIG. 10 shows a flowchart of the interrupt routine, which is activated by the fall of the pulse signal from the input circuit 10.

In step 61, the value Ti of the free run timer is read,
At step 62, the pulse interval Tn is determined from the difference from the free run timer value Ti-1 at the time of the previous interrupt. In the following step 63, the engine rotational speed NB is determined from the pulse interval Tn.
is required.

(Effects of the Invention) As described in detail above, the fuel injection timing control device of the present invention corrects the target injection timing based on the signal from the excess air ratio detector. Since optimal injection timing control can be performed even when the air filter is clogged, excellent effects such as vibration and noise reduction and exhaust gas purification can be achieved.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of the present invention, FIG. 2 is an overall configuration diagram according to an embodiment of the present invention, FIG. 3 is a sectional view of main parts showing an electric to hydraulic timer and an actual injection timing detector, and FIG. Figure 4 is a rotational speed detector and its input circuit diagram, Figure 5 is a timing chart showing waveforms of the detector and various parts of the circuit, Figure 6 is a sectional view of main parts showing the installation position of the injection amount detector, 7th
The figure shows the excess air ratio detector and its input circuit, Fig. 8 Cal shows the output characteristics of the excess air ratio detector, Fig. 8 (bl shows the output characteristics of the input circuit, and Fig. 9 shows the injection timing control 10 is a flowchart of the main routine of
) does not indicate the basic target injection timing T8ΔSE.
Figure (bl is excess air ratio λ and injection timing control height 'FCOt4
It is a characteristic diagram showing the relationship with p. ■...Diesel engine, 2...Fuel injection pump, 3
... Driving pleasure detector group, 4... Excess air ratio detector,
5...Target injection timing calculation means, 6...Target injection timing correction means, 7...Injection timing adjustment means.

Claims (1)

[Scope of Claims] A group of operating condition detectors for detecting various operating conditions of a diesel engine, a target injection timing calculation means for calculating a target timing based on signals from the group of operating condition detectors, and a target injection timing A fuel injection timing control device comprising: an injection timing adjustment means for adjusting the injection timing to match the actual fuel injection timing; A fuel injection timing control device comprising: target injection timing correction means for correcting the target injection timing based on a signal from the excess air detector.