JPH03501511A - Fuel injection system for diesel engine - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] Fuel injection device for diesel engine [prior art] The present invention is for detecting the rotational direction of the crankshaft of a diesel engine at the time of starting. method and device, which allows the engine to be Jin can be stopped immediately. After kickback when starting the internal combustion engine, There is a possibility that the gin will start rotating in the wrong direction. Possible cause when rotating in the wrong direction Apart from dangerous consequences, there is also the possibility of mechanical damage to the engine. Eyes of the invention The goal is to set the start of fuel injection at seven cylinders in relation to the top dead center (TDC) of the engine. The purpose of this is to detect rotation in the wrong direction.

DE-A-2655046 has advance angle (injection start time relative to TDC). ) is described, and this method does not measure the actual ignition progress. , and compared to the desired injection advance. The actual injection progress is determined by the pump on the crankshaft. Reference mark formed by the lus generator disc and senna in the vicinity of the injection nozzle obtained by measuring the crank angle relationship between the start of injection detected by It will be done.

[Advantages of the present invention]

According to claims 1 and 2 respectively, the present invention provides a jib easel engine at the time of starting. A method and apparatus for detecting the rotational direction of a crankshaft are provided. This is a mistake For example, this signal may be supplied to the engine governor to cause the governor to control the injection point. It can be used to immediately stop the engine by setting the pump to zero delivery. It has the advantage of being able to

The actual fuel injection detected by the injector is extremely slow, below the starting speed. For example, it is not easy with an engine running at a speed below 400 r, p, m, k, so the injection point It is advantageous to detect the start of the injection stroke at the pump. Start of injection stroke and actual injection A small delay between the start is not important and this delay is in any case very low. It is not clearly indicated at low engine speeds. The start of the injection stroke is the camshaft of the injection pump. The start of the injection stroke is directly related to the angular position of the camshaft. It can be detected by

〔drawing〕

The present invention will now be described in detail by way of example, with reference to the accompanying drawings.

Figure 1 shows how the direction of rotation of the crankshaft is detected in a diesel engine according to the present invention. Figure 2 is a block circuit diagram of the device for this purpose. Figure 3 is a diagram of the 6-cylinder diesel engine shown in Figure 2. Figure 4 shows the cam lift and pulse diagram for the fuel injection pump for the 8-cylinder engine. 5 is a side view of another embodiment of the cam, FIG. Figure 6 is a diagram of pulses related to the cam in Figure 5, and Figure 6a is a revised pulse diagram of Figure 6. This is a diagram.

[Explanation of Examples]

A pulse generator 10 is attached to the crankshaft of a diesel engine, and This means that one or more reference pulses BM are generated at precise timing relative to the crankshaft rotation. Form. These reference pulses are controlled by electronic governor operation and/or DE-A- 265,3046 or electronic ignition as described in DE-A-3202614 It may also be used to operate the advance control device. According to the invention, the reference pulse BM is used as a reference such that a signal indicating or indicating the start of fuel injection can be obtained based on the used. , the injection start signal is the actual injection start SB or the actual injection pump signal. may be the start FBA of the fuel delivery, but advantageously the start FB of the injection stroke; This is the signal obtained from the inductive transducer 11 in response to the reciprocating movement of the pump plunger. It may be. Based on fuel compressibility and operating time <, SB, FBA, F The slight difference between Not important at all.

The reference mark BM and the injection start signal FB are the start inputs of the counter 12, respectively. For example, the counter input to the stop input indicates the engine speed. A count pulse train n indicating the rotational speed of the shaft is supplied. The speed signal n is D Another pulse on the crankshaft as described in E-A-2653046 For example, the advance angle degree (degree rotation n) may be a pulse train adapted to form one pulse for n). 'a Alternatively, the speed signal n can be derived from the reference mark BM using a frequency multiplier. .

The output count of counter 12 represents the actual injection angle α and the comparator 14 and the comparator indicates that this angle is the limit value given by the reference memory 16. Check whether αrt- has been exceeded.

FIG. 2 shows a cam 18 with camshaft symmetry. cam by arrow 20 on the cam corresponding to the start of the delivery stroke when rotated in the normal direction shown. The point is marked as FB. If it rotates in the wrong direction, it will start the delivery stroke. , the corresponding point is indicated by FB'. The working angle of the cam 18 in Fig. 2 is 60 It is Q. In other words, the angular range between the start of the delivery stroke and the end of the suction stroke is 60'. Yes, this applies to any direction of rotation. This angle is 4 cycle engine For gin, it is equal to a crank angle of 120°.

The lower part 12 of FIG. 2 shows the formation of the reference pulse BM, and the upper part 12 of FIG. is the crank angle and reference pulse for a 6-cylinder, 4-stroke engine, A cam lift related to BMK is shown. The TDC of a given engine cylinder is 20' after the corresponding reference mark BM.

The engine normally prepares the injection advance, that is, the actual injection start time is determined by the injector. The cylinder is equipped with a device for adjusting the TDC of each cylinder. However, in Fig. The rank angle is shown and the signal FB is related to the crank angle. Enji When the engine starts, the injection advance is zero as shown by the dashed line 24 (BM 2). 0°], at idle link speed the injection is at T, as shown by the solid line 26. When it is advanced 10c' ahead of DC (10° after BM) and the speed increases, the dotted line 28 We proceed further as shown by.

The reference mark BM is placed 20o ahead of the TDC of the engine cylinder to which it belongs. Once formed, the counter 12 counts engine speed-dependent pulses n' (H). start.

The transducer 11 assigned to the cam 18 and with the assigned engine cylinder is thereby As soon as it detects that each injection pump plunger has started its lifting stroke , the counter 12 stops counting. Counter 12 when the engine starts normally As shown on the left side of Fig. 3, the count α stored in I guess. However, if the engine crankshaft starts rotating in the wrong direction, the counter As can be seen from the right side of the 61st count, the count α of 12 reaches a value equivalent to more than 40'J. do.

Special table 13-501511 (3) A reference center between 20° and 40° is provided from memory 16 to the reference input of comparator 14. set limits on the response of the comparator. Therefore, the crankshaft is in the wrong direction. When the engine rotates to For example, the injection pump is set to zero fuel output. As long as the engine doesn't come to a standstill A holding circuit (not shown) is provided to prevent resumption of fuel injection.

Figure 4 is similar to Figure 3, except that Figure 4 is an 8-cylinder, 4-stroke diesel engine. Regarding engine. This value is 20°, and the crankshaft has rotated in the wrong direction. In this case, the smallest possible value is 406, so the median value is not critical. There are large differences that are easy to detect.

A cam 22 is shown in FIG. 5, and the working angle between FB and FB' is 36. This corresponds to a crank angle of approximately 72°. Figure 6 shows the correct direction. The maximum value of α for rotation is less than or equal to 20° and the minimum value of α in case of wrong direction. is shown to be 28c' or more. Therefore, 20°~2 for αr There is only a narrow selection of 8 degrees. Having to work with such precision In order to avoid this, the reference mark BM'i TDC should be set as shown in Fig. 6a. The 20° advance against can be increased to 40°. correct in this case For acceleration with idle link speed 1 during rotation in direction 20, the value of α is 30c ', and the misdirection can be 18°. Therefore, the reference value αr is no longer critical, but instead of counting up counter 12, The counter must be adjusted down and the counter count must be adjusted down before the count is stopped. In order to prevent the output from reaching the comparator, between the counter and the comparator, A controlled /F-"-t must be provided.

Increasing the difference in α between the correct and incorrect direction of rotation for in-line injection pumps Another possibility to increase this is to modify the rear curve of the cam. This is after This cam curve shape is possible because no injection operation is performed.

When the device of the invention is installed, the injection pump is servo-controlled by the injection angle governor. An injection timing adjustment device may be provided, and the feedback signal of the governor may be DE -A-! Actual injection start (SB control) as described in 1202614 from a separate sensor placed near the injection nozzle to detect .

The method and apparatus of the invention are not necessary once the engine is started in the correct direction. and take care to ensure that the engine stop signal is cut off when the starting process is completed. be able to. SB of the injection timing adjustment device when the device is operating normally when the sensor 11 fails or to interfere with the controlled operation of the standby mechanism in the event of a FB control failure. prevent.

Sensor 11 can also be used for FB control or for SP control. A sensor for detecting the actual start of injection can be used in the apparatus and method of the present invention. I can do it.

, D mutual 1.・ international search report kh-culm 1-to 1^ra bowl Lu 1 Oshiuchi Nφ PC knife/EP aB10086B international Investigation report PCT/EP 8810OB68

Claims (6)

[Claims] 1. In a method for detecting the direction of rotation of a crankshaft in a diesel engine , at a special angular position on the engine crankshaft with a signal indicating or indicating the start of injection. Measure the angle difference with the provided reference mark, compare it with the reference value, and determine the rotation direction. characterized by indicating whether the actual value is larger or smaller than the reference value; A method for detecting the direction of rotation of the crankshaft in a diesel engine. 2. In a device for detecting the rotation direction of the crankshaft in a diesel engine , a reference mark (SB ) and a pulse generator (10) for representing or indicating the start of fuel injection. A sensor (11) for generating a signal (FB, FBA or SB) and a reference map. a member (α) for generating a signal (α) indicating the angular difference between the 12), and if the angular difference signal (α) is larger or smaller than the reference signal (αr), and a comparator (14) for generating an output signal when A device for detecting the direction of rotation of the crankshaft in a diesel engine. 3. The member (12) for generating the angular difference signal (α) is a counter (12). , this counter is supplied with a counting pulse (n) representing the engine speed. 3. The device of claim 2, wherein the device is configured as follows. 4. The sensor (11) responds to the start of the delivery stroke (FB) of the assigned injection pump piston. 4. The device according to claim 2 or 3, wherein the device 5. The curve behind the injection pump cam (18) indicates positive rotation of the crankshaft. In order to increase the difference between the value of the signal (α) and the value of the signal (α) indicating wrong direction rotation. 5. Device according to any one of claims 2 to 4, wherein the device is modified. 6. To generate an engine stop signal if the engine rotates in the wrong direction when starting Device according to any one of claims 2 to 5, for use in.