JPS6165049A - Safety device in diesel-engine - Google Patents

Abstract

PURPOSE:To prevent an engine from overrunning, by providing a control device for controlling either one of a solenoid valve and an intake-air throttle valve to stop the engine when no signal indicative of engine rotational speed is delivered over a predetermined time. CONSTITUTION:At step 120 the data on a fail counter Cfail is added with one. At step 122, if Cfail>=5, it is judged that no signal indicative of engine rotating angle is delivered over 40msec. At step 124, when a solenoid valve is judged to be closed, it is shifted to step 126 to open the solenoid valve. Thus, it is detected that the engine rotational speed detecting system is failed, and therefore, it is possible to prevent the engine from overruning.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a safety device for a diesel engine, and in particular,
The present invention relates to a diesel engine safety device that enables stable engine control even in the event that a system for detecting engine rotational speed breaks down.

[Conventional technology]

A plunger is provided which is rotated and reciprocated by being driven by a crankshaft within the plunger, and the reciprocating rotation of the plunger expands and contracts a high pressure chamber formed by the plunger tip surface and the inner wall surface of the cylinder to draw in and pressure feed fuel, The fuel injection device is configured to control the amount of fuel by communicating and cutting off the high-pressure chamber and the low-pressure chamber by opening and closing a solenoid valve provided in a passage that bypasses the high-pressure chamber and the low-pressure chamber. There is something. As mentioned above, the fuel injection amount # of a diesel engine equipped with such a configuration is controlled by opening and closing a solenoid valve, but such a solenoid valve detects the engine rotation speed. Opening/closing is controlled by a control device that receives a detection signal from an engine rotation speed sensor and calculates and determines the amount of fuel based on this detection signal. A device similar to this configuration is disclosed in Japanese Patent Application Laid-Open No. 59-65523.

[Problem that the invention seeks to solve]

According to such a fuel injection device for a diesel engine, if the system for detecting the engine speed has a failure, such as a disconnection of the engine speed sensor or a disconnection of the wiring from the engine speed sensor to the control device, the engine speed detection will be stopped. Since the signal is no longer input to the control device, the solenoid valve is no longer controlled to open or close. In other words, the solenoid valve remains in the state it was in when the engine speed detection system failed.

Therefore, if the solenoid valve was controlled to be closed by the control device at the time of the failure, the solenoid valve will remain closed from then on, so the C fuel will not be spilled and the entire amount of fuel will be sent to the diesel engine. It gets sprayed. As a result, the diesel engine could overrun.

The present invention has been made in view of the above-mentioned circumstances, and it is an object of the present invention to provide a fail-safe device for a diesel engine that prevents engine overrun by detecting a failure of the engine speed detection system. purpose.

[Means for solving problems]

In order to achieve the above object, the present invention provides a plunger that is rotated and reciprocated within a cylinder, and the high pressure chamber formed by the plunger tip surface and the inner wall surface of the cylinder is created by the rotation and reciprocation of the plunger. a fuel injection device configured to draw in and pressure feed fuel, and to control the amount of fuel by communicating and cutting off the high pressure chamber and the low pressure chamber by opening and closing a solenoid valve; In a diesel engine comprising a control device that calculates a fuel injection amount and controls the opening and closing of the solenoid valve based on the calculation result, and also controls the opening degree of the auxiliary intake throttle valve, the control device is configured to control the engine rotation speed signal. When it is determined that the solenoid valve is closed when it is detected that no input has been made for a certain period of time or more, either the solenoid valve or the intake throttle valve is driven and controlled.

This is characterized by a configuration in which the engine is controlled to stop.

[Effect]

A signal for obtaining the engine speed and a signal for obtaining the accelerator opening are input to the control device. The control device obtains the engine rotation speed and accelerator opening from these signals and calculates the fuel injection amount. Further, the opening degree of the sub-intake throttle valve is controlled by the control device. Opening and closing of the electromagnetic valve is controlled based on the calculation result of the fuel injection amount. here,
The control device determines whether or not the engine rotational speed signal is not input for a certain period of time or more, and if the engine rotation speed signal is not input for a certain period of time or more, then determines whether or not the solenoid valve is closed. As soon as the solenoid valve is determined to be closed, the control device opens the solenoid valve or
Alternatively, the sub-intake throttle valve is fully closed to control the engine to stop. This prevents engine overrun.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 2 is a schematic diagram of a diesel engine equipped with an electromagnetic spill distribution type fuel injection pump. The fuel filtered by the filter is passed through the fuel supply port 6 to the pressure regulating pulp 8 by a vane type feed pump (illustrated expanded at 90 degrees) 4 driven by the drive shaft 2.
Guided by this pressure regulating pulp 8
After the pressure is adjusted, the pump chamber 12, which is a low pressure chamber within the pump housing 10, is filled. Pump chamber 12
The fuel filled in the pump chamber 12 lubricates the working parts and at the same time flows into the plunger 1 via the suction boat 14.
6 is sent to a high pressure chamber 18 formed at the tip. Also,
Some fuel is circulated through the overflow valve 20 back to the fuel tank to drain excess fuel and cool working parts.

Suction groups 22 of the same number as the number of cylinders are bored at the tip of the plunger 16, and a distribution boat 26 communicating with an axial boat 24 is bored in the radial direction of the plunger 16. Further, a cam plate 28 is fixed to the tail end of the plunger 16, and the same number of rollers 32 as the number of cylinders fitted into the roller ring 30 are in contact with the cam plate 28. This plunger 16 is inserted into the cylinder 34 from the tip side, and the tip surface of the plunger 16 and the cylinder 34
A high pressure area 18 is formed by the inner wall surface of 4. The cylinder 34 is provided with a suction boat 14 and distribution passages 38 of the same number as the number of cylinders that communicate with the delivery pulp 36 from the inner surface of the cylinder. A solenoid valve 44 is attached to communicate and cut off the communication passage 40 of the pump housing 10KR1. This communication passage 40 allows the high pressure chamber 18 and the pump chamber 12 to communicate with each other. Also,
When the solenoid 46 is energized, the solenoid valve 44 closes the valve body 42.
When the solenoid is de-energized, the valve body is protruded and the communication path 40 is cut off.

The drive shaft 2 protrudes toward the pump chamber 12 and is connected to a cam plate 28 via a coupling. The cam plate 28 is fixed to the plunger 16 and is pressed against the roller 32 by a spring 50. Therefore, the cam plate 28 is rotated by the drive shaft 2, and the cam crest of the cam plate 28 becomes the loaf' depending on the state of contact between the row 232 and the cam plate 28.
32, the granger 16 is reciprocated a number of times equal to the number of cylinders during one revolution.

At the bottom of the fuel injection pump, there is a hydraulic timer (90° expansion) that changes the phase of the drive shaft 2 and the cam plate 28 that drives the granger 16 to change the fuel injection timing using changes in the fuel supply pressure. ) 52 is provided. According to this timer 52, the spring 5
4 pushes the timer piston 56 in the direction of injection delay, and as the near-sin rotational speed increases, the oil feeding pressure increases and the piston 56 is pushed against the elastic force of the spring 540. The pump 30 is rotated in the opposite direction to the direction of rotation of the injection pump, and the fuel injection timing is advanced in proportion to the oil pressure. The hydraulic pressure acting on the piston 56 is controlled by a solenoid valve 48.

A signal rotor 60 having a plurality of teeth is fixed coaxially with the drive shaft at the tip of the drive shaft 2, and a pickup 62 is attached to the roller ring 30 so as to face the circumferential surface of the signal loader 60. . Therefore, when the signal otor rotates together with the drive shaft, the pickup 62 outputs an engine rotation angle signal.

Further, a fuel injection cut pulp 64 is attached to the pump housing IOK as a fuel injection stop device that stops fuel injection by cutting off the suction boat 14.

The delivery pulp 36 is connected to a fuel injection valve 68 that is installed so as to protrude into the auxiliary combustion chamber of the diesel engine 66. A glow plug 70 is attached to this sub-combustion chamber so as to protrude therefrom.

74 is an accelerator sensor that detects the accelerator opening degree, 76 is a pressure sensor that detects the intake pipe pressure, 78 is a water temperature sensor that detects the engine cooling water temperature, and 80 is a glow relay.

Further, 84 is a venturi, and the venturi 84 is constructed by dividing the intake passage into two parts in the direction of flow of intake air, and disposing a main intake throttle valve 86L on one side and disposing a sub-intake 86b on the other side. There is. An accelerator sensor 74 is attached to the main intake throttle valve 86aK, which works in conjunction with the main intake throttle valve 86aK and detects the accelerator opening degree based on the opening of the main intake throttle valve 86aK. Sub-intake throttle valve 86
b is connected to the actuator 88 via a rod 88a. The actuator 88 is divided into an A chamber and a B chamber by a diaphragm connected to a rod 88aK. The A chamber of the vacuum cutter 88 is communicated with a vacuum switch valve 90A, and the B chamber is communicated with a vacuum switch valve 90BK. Both switch pulps 90A and 90B are connected to a negative pressure source.

When the vacuum switch pulp 90B is opened and the vacuum switch valve 90A is closed, negative pressure is introduced into the chamber, chamber A is reduced, and the intake throttle valve 11 is controlled to be half open. Both vacuum switch valves 90A
, 90B, the auxiliary intake throttle valve 86b is fully opened, and conversely, when the vacuum switching pulps 90A and 90B are closed, the sub intake throttle valve 86b is fully opened.
If both 0B and 0B are opened, the auxiliary intake throttle valve 861) is fully closed.

However, the above pickup 62 and accelerator sensor 7
4. The pressure sensor 76 and water temperature sensor 78 are connected to an input port of a microcomputer 82 as a control device. Further, the output port of the teno microcomputer 82 as a control device is connected to the glow plug 70 via the glow relay 80, and the solenoid 46 of the solenoid valve 44, the solenoid of the solenoid valve 48, and the fuel cut pulp 6.
4 solenoid and vacuum switch valve 90
A, connected to 90B.

That is, the microcomputer 82 as a control device.
For example, as shown in FIG. 3, a central processing unit (CPU) 82
A. Read-only memory (ROM) 82B5 Random access memory (RAM) 82C1 Backup program (BU-RAh"1) 82D.

It is composed of an input/output capo (Ilo) 82F, an analog/digital converter (ADC) 82F, a drive circuit 82G, a transistor 82H, and the like.

The ADC 82PK receives an intake pipe pressure signal from the pressure sensor 76, an accelerator opening signal from the accelerator sensor 74, and a water temperature signal from the water temperature sensor 78.
The signal is sequentially converted into a digital signal according to instructions from A. Also, l1082E is 1. Through the drive circuit 82G, a solenoid valve opening/closing signal is output to the transistor 82H whose emitter is grounded and whose collector is connected to the solenoid 46 of the solenoid valve 44 through a resistor R, and at the same time outputs fuel to the fuel injection cut valve 64. It outputs an injection stop signal, outputs a timer signal to the solenoid valve 48, and outputs a no 80 hegelow signal. In addition, the rotation angle signal from l1082EICH and pickup 62 is input, and the resistor R
A voltage signal is input from the connection point between the transistor 82H and the collector of the transistor 82H. Furthermore, the ROM82B contains a main routine, a disconnection detection interrupt routine, and
Programs for the disconnection detection routine and failsafe routine are stored in advance, and the accelerator opening ACCP
A program that calculates the basic fuel injection amount Q0 from Maps etc. are stored in advance.

Next, the processing routine of this embodiment will be explained with reference to FIG.

FIG. 1 (8) shows the main routine, in which the engine speed NE is determined from the rotation angle signal output from the pickup 62 at step 100, and the accelerator speed ACCP is determined from the output of the accelerator controller 74.
Based on the following formulas (1) and (2), the basic fuel injection amount Qo is determined, and this basic fuel injection amount Q0 is calculated from the water temperature sensor 7.
8. The fuel injection amount Q is determined by correcting the fuel injection amount using the output, etc.

(Idle area) However, Ki Castle 1,75 x ACCP + 79.0, Kic
-10.

(Partial load and all W range) However, when Ochi≦ACCP≦20chi, KPA-1,56xACCP-4-20, KP! 1-1
．． 94xACCP-)-50°, and 20chi(ACCP-)-50°.
≦100%, KPA-0,314xACCP-)-4
5, Kpm-2, 18xACCP+45.2.

Therefore, the basic fuel injection amount Qo-MAX (QI OLE
.

QPART).

In the next step 102, based on the engine speed NE and the fuel injection amount Q calculated in step 100, the spill angle θ is calculated by interpolation from the spill angle map stored in the ROM 82BK. Next step 10
4, the integer part obtained by dividing the spill angle θ by the crank angle 11°25° CA) corresponding to the interval between the convex portions of the signal rotor 60 is stored as Qc in a predetermined area of the RAM 82C. Also, in step 106, step 10
The remainder of the calculation in step 4 is converted into time and set as TSP, which is stored in a predetermined area of the RAM 82C.

FIG. 1 is a flowchart showing an input interrupt routine for an engine rotational speed detection signal.

In step 108, 1 is added to the data stored in the interrupt counter CNIRQ for the engine speed NE, and the data is returned to the interrupt counter CNIRQ for the engine speed NE.
and store it in the fail detection counter Cfail.
Let be zero. By the way, is the engine pickup 62 1f? At the time of failure detection counter Cfai
l is not cleared, and the Senna connection can be detected. Next, in step 110, it is determined whether the data of the interrupt counter CNIRQ of the engine speed NE is equal to Qc calculated in the main routine of FIG. 1(G). The determination at step 110 is to determine whether or not there is a spill period before the next engine rotational speed NE111 is included.In step 110, if there is a spill period, step 112 In step 112, the output conveyor register 9 (0°C,
R), 'Current time (time at the time of interruption) - l - Ts
After storing p' and making spill possible, the process moves to step 114. If it is determined in step 110 that there is no spill time, the process similarly proceeds to step 114. In step 114, it is determined whether the content of the NFJ interrupt counter CN IRQ is, for example, 21 m 9, in other words, whether it is time to close the electromagnetic valve 44 as a spill valve. In this step 114, CNIQR
If it is determined that it is time to close the solenoid valve 44, the process moves to step 116; otherwise, the process moves to step 118. In step 116, the output conveyor register (0, C, R) K, 1 current time + α (time until the interrupt calculation ends) 1 is stored, and the process moves to step 118. In step 118, the engine rotation speed NE is determined from the rotation angle signal from the pickup 62. Although not shown, the solenoid valve 44 is opened and closed at the time set in the output conveyor register.

FIG. 1 is a flowchart illustrating a fixed time interrupt routine. This routine lasts for a certain period of time (10 in this example).
ms) gK interrupt processing.

At step 120, an increment function is executed to add 1 to the data stored in the fail counter Cfail. perform operations. Next, in step 122, it is determined whether the fail count Cfail is, for example, 5 or more. If it is determined in step 122 that Cfail≧5, it is determined that the engine rotation angle signal from the engine rotation speed detection system such as the pickup 62 has been input for 40 (ms) or more. Therefore, step 122
Then, it is determined whether the solenoid valve 44 is in a closed state.

In this step 122, if it is determined that the solenoid valve 44 is open, the engine overrun phenomenon will not occur, so the routine proceeds to another routine without applying any operation β. On the other hand, when it is determined in step 122 that the solenoid valve 44 is closed, K moves to step 126 and performs an operation to open the solenoid valve 44 in this step, since there is a risk that an engine overrun phenomenon will occur. Add. That is, 1 current time + β (time until calculation completion) 1 is stored in the output conveyor register. Therefore, when the time set by the output conveyor register is reached, the solenoid valve 44 is opened, so that engine overrun can be prevented.

The first embodiment of the present invention is as described above.

Next, another implementation of the present invention will be described. The first embodiment of the present invention is to control the opening of the solenoid valve 44 by detecting that the engine speed signal is not input for a certain period of time when the engine speed detection system fails. Instead of opening the electromagnetic valve 44 in the embodiment described above, the second practical example of the present invention completely closes the secondary shark valve 86b to prevent engine overflow.

That is, in the routine shown in FIG. 1q, when the flow passes through step 126, when a signal is output from the output conveyor register, both the vacuum switching valves 90A and 90B are opened, and the sub-intake throttle valve is opened. 86b is fully closed.

Even in the non-embodiment, it is possible to prevent engine overrun.

[Effects of the invention] ′ As stated above, according to invention 7 (x), the engine can be stopped even if the engine speed detection system device breaks down, so the effect is that engine overrun can be prevented. There is.

[Brief explanation of drawings]

In Fig. 1) ~ 0 is a flowchart shown to explain the operation of the embodiment of the great invention, Fig. 2 is a schematic diagram showing a diesel engine to which the embodiment of the great invention is applied, and Fig. 3 is a flowchart showing the operation of the embodiment of the great invention.
FIG. 2 is a block diagram showing the control device shown in FIG. 4... Vane type feed pump, 12... Pump chamber (
low pressure chamber), 16... plunger, 18... high pressure chamber,
44... Solenoid valve, 82... Kari@Sho, 84... Ventu'L86a... Main intake relief valve, 86b... Sub-intake throttle valve.

Claims (1)

[Claims] (1) A plunger that rotates and reciprocates within the cylinder is provided, and the reciprocating rotation of the plunger expands and contracts the high pressure chamber formed by the plunger tip surface and the inner wall surface of the cylinder, sucks in fuel, and pumps the fuel. A fuel injection device configured to control the amount of fuel by communicating and disconnecting the high pressure chamber and the low pressure chamber by opening and closing a valve, and a fuel injection device configured to control the amount of fuel by communicating and disconnecting the high pressure chamber and the low pressure chamber. In a diesel engine, the diesel engine includes a control device that controls the opening and closing of the electromagnetic valve and controls the opening degree of the auxiliary intake throttle valve based on a calculation result, and the control device detects that an engine rotation speed signal is not input for a certain period of time or more. 1. A safety device for a diesel engine, characterized in that when the electromagnetic valve is determined to be closed when the electromagnetic valve is closed, the engine is stopped by controlling one of the electromagnetic valve and the intake throttle valve.