JPS6143272A - Glow-plug controller for diesel engine - Google Patents

Abstract

PURPOSE:To shorten the preheating time by starting the elecrric conduction to a glow plug when the plug-in of a key of a Diesel engine is detected and by suspending the electric conduction when a key switch is not set to a prescribed operation state for a prescribed time after the plug-in of the key. CONSTITUTION:The signals supplied from a key switch 1 and a key plug-in detector S2 are input into a control unit 4, and said signal is calculation-treated by a microcomputer 5, and the electric conduction to a glow plug 3 is controlled. When a key 2 is plugged into the key switch 1, the signal H supplied from the key plug-in detector S2 initializes a flip-flop 8 through an inverter I1 and a gate G3, and a power switch 7 is turned-ON, and the microcomputer 5 starts operation to start electric conduction to the glow plug 3. Though a power source is cut-off after the lapse of a prescribed time, if the key 2 is operated to the ON or starting position before said cut-off, a power input passage of the control unit 4 can be secured through a contact point S1.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a glow plug control device for an automobile diesel engine.

<Prior Art> In a conventional glow plug control device used in an automobile diesel engine, first, as shown in FIG.
For example, the engine starting key switch 1 is provided with a preheating ON/OFF operation position.

The glow plug is configured to be energized at the operating position of the preheating ONJ.

To operate and operate the device, first insert a key into the key switch 1, as shown in FIG. Next, move this key through the rOFFJ and rAccJ operating positions to the above-mentioned "preheating ONJ" operating position.Then, the control unit (C/U) is powered on at this "preheating ONJ" operating position. As a result, the control unit operates to start energizing the glow plug.Then, when the temperature of the glow plug becomes sufficiently high after a predetermined preheating time t2 from this point on, the A message indicating that preheating is complete will be emitted.

As described above, the conventional glow plug control device starts energizing the glow plug only when the key is inserted into the key switch and the inserted key is brought to the specified operating position. It was composed of

<Problems to be Solved by the Invention> However, in the conventional glow plug control device described above, the glow plug cannot be energized until the operation time t1 from when the key is inserted to when the key is brought to the operation position has elapsed. Since the preheating time t2 is not started, there is a problem in that it is necessary to wait for a long time equal to the operation time t1 plus the preheating time t2 before the engine is ready to start.

<Means for Solving the Problems> The purpose of the present invention is to solve the above problems, and as a means to achieve this purpose, as shown in FIG. 1, a diesel engine starting operation is performed. A key insertion detection means detects that an operation key is inserted into a key switch for the purpose of operation, and from the time when the key insertion detection means detects the insertion of a key, the glow plug is energized when the operating power is turned on. and a timing device that measures a predetermined waiting time from the time when the key insertion detection device detects the insertion of the key, and when the timing by the timing device is completed and the key switch is turned on. The present invention is characterized in that it includes an operating power cutoff means for cutting off the operating power of the energization control means when a predetermined operating state is not set.

(Function) The above means reliably advances the start of energization to the glow plug, thereby shortening the waiting time until the engine is ready to start.

Further, if there is no intention to start even if the key is inserted, the operating power of the energization control means is cut off after a predetermined waiting time, thereby automatically avoiding wasteful power consumption.

<Embodiments> Hereinafter, preferred embodiments of the present invention will be described based on the drawings.

FIG. 2 shows an embodiment of a glow plug control device for a diesel engine according to the present invention.

The glow plug control device shown in the figure first includes a key insertion detection means S2 and a control unit 4.

The key insertion detection means S2 is constituted by a microswitch, a photoelectric switch, or the like disposed at the back of the key insertion hole of the starting key switch 1. This key insertion detection means S2 outputs whether or not the operation key 2 is inserted at a binary logic level of "H" (high level) and L" (low level). In this case, the operation key 2 is inserted, it outputs "H", otherwise it outputs "L".

As shown in FIG. 3, the key switch 1 is
It has the operating positions of rACCJ, rONJ, rstart.

These operating positions are sequentially arranged along the rotational operating direction of the key.

The control unit (C/U) 4 includes a microcomputer (
CPU)5. Power supply circuit 6. Power switch circuit? , RS flip-flop8. It has a built-in A/D converter 9, etc.

The microcomputer 5 has a function as an energization control means for controlling energization to the glow plug 3, and the like.
A software-based function is provided as a timer for measuring a predetermined waiting time t3 from the time when the key insertion detection means S2 detects insertion of the key 2. In this case, the glow plug 30 energization control is performed via the switching transistor Q3 and the electromagnetic relay RYI.

The power supply circuit 6 receives the vehicle battery power supply vb as an input,
This is stepped down and stabilized to a predetermined voltage and output. The stabilized power supply Vccl output from the power supply circuit 6 is supplied to, for example, the microcomputer 5 as the main operating power supply inside the control unit 4. At any given time, the battery power supply vb is input to the power supply circuit 6 through two paths. The contact S1 of the key switch 1 is interposed in series on one of the paths. This contact S1 is a contact that closes when the key switch 1 is set to the rONJ or "start" operating state. In this case, "ON" is set when the engine is put into operation, and "START" is set when the engine is started. Further, a power switch circuit 7, which will be described later, is provided in series on the other path as an operating power supply cutoff means. The power that has passed through either one of these two paths is input to the power supply circuit 6-. In other words, the control unit 4 turns the key switch l "ON",
"Start" setting or O of power switch circuit 7 described later
It operates with either one of N operations.

In addition, a diode D1. for backflow prevention is installed in each of the above two power supply input paths. D2 is inserted.

Further, the power supply circuit 6 is configured to control the microcomputer 5 at the initial stage when the power input is applied and the output voltage is stabilized.
A reset signal RESET is issued to initialize the settings. It has a so-called power-on reset function.

The power switch circuit 7 is constructed using a pnp bipolar transistor Q1 and an npn bipolar transistor Q2. This switch circuit 7 is connected to the RS
When the cent output Q of the flip-flop 8 takes the logic level of "H", it becomes ON state.

The RS flip-flop 8 is composed of two two-way NAND gates G1 and G2.

The detection output of the key insertion detection means S2 is input to the cent human power S. Further, a time measurement completion signal for the waiting time t3 is inputted to the reset manual R from the microcomputer 5.

Here, the detection output from the key insertion detection means S2 is introduced into the control unit 4 and then branched into two. One of the branches is Invar 211, 2-man NAND
It is input to the cent input S via one logic input of the gate G3 and a time constant formed by the resistor R1 and capacitor C1. The cent output Q of the flip-flop 8 is input to the other logic input of the two-man NAND game (G3). Further, the other branch is inputted to the reset input R via a time constant formed by a resistor R2 and a capacitor C2.

The above flip-flop 8. Inverter ■1 and NAND
A low power consumption C-MO5 logic circuit is used for the gate G3. The operating power supply Vcc2 is generated from the "H" output of the insertion detection means S2 by a constant voltage circuit consisting of a resistor R3, a Zener diode z1, and a capacitor C3.

The A/D converter 9 converts the energizing voltage of the glow plug 3 into a digital signal and supplies it to the microcomputer 5. The microcomputer 5 detects the temperature of the glow plug 3 based on the energization voltage, and further controls the energization time of the glow plug 3 based on the detected temperature. Furthermore, by monitoring the energizing voltage, disconnection of the glow plug and other failures can be detected.

Next, the operation of the glow plug control device described above will be explained with reference to FIG.

First, when the operation key 2 is inserted into the key switch 1, the key insertion detection means S2 issues a detection output of "H". This causes flip-flop 8. The inverter If and the two-man power NAND gate G3 start operating upon receiving the power supply VCC2. At the start of this operation, the flip-flop 8 is initialized through the following steps.

First, the operating power supply Vcc2 of the flip-flop 8 is turned on. Next, a little later than the rise of this power supply Vcc2, the human reset power R of the flip-flop 8 goes to "L".
It rises to “H” from After this, slightly later than the reset human power R, the cent human power S changes from "L" to "H".
stand up.

Through the steps described above, the set output Q of the flip-flop 8 is initially set to "H". As a result, the power switch circuit 7 is turned on, and the control unit 4 is turned on.
The main power supply V'c c 2 is supplied to. by this,
The microcomputer 5 starts operating from the initial setting state and controls the energization of the glow plug 3. As described above, when the operation key 2 is inserted into the key switch 1, the glow plug 3 is immediately energized.

Then, by the time the temperature of glow plug 3 has risen sufficiently,
For example, if the microcomputer 5
J is displayed.

On the other hand, when the waiting time t3 has elapsed since the start of energization of the glow plug 3, the microcomputer 5 issues a timing completion signal. When this time measurement completion signal is issued, the flip-flop 8 is reset and its set output Q is inverted to "L". As a result, the power input path by the power switch/notch circuit 7 is cut off when the waiting time t3 has elapsed. Along with this,
The other logic input of the two-man powered NAND gate G3 is “L”.
", and cent input to the flip-flop 8 is prohibited. This prevents the flip-flop 8 from being erroneously re-cented due to external noise or the like.

Here, before the power input path by the power switch circuit 7 is cut off, turn the key 2 on or off.
When the control unit 4 is brought to the operating position, the power input path for the control unit 4 is secured through the contact S1, which closes at this operating position. In addition, if the key 2 is inserted but there is no intention to start, and the key is left in the operating position of "rOFF" or rACCJ, the main power supply Vccl of the control unit 4 will be cut off after the predetermined waiting time t3 has elapsed. , whereby the power supply to the glow plug 3 is automatically stopped.

As described above, by starting energizing the glow plug 3 immediately from the moment the key 2 is inserted, the time to start energizing the glow plug is reliably brought forward, and this allows the engine to reach a state where it can be started. The waiting time can be reduced. Further, if there is no intention to start the engine, the power supply is automatically stopped after the predetermined waiting time t3, so that no power is wasted.

(Effects of the Invention) As is clear from the description of the embodiments above, the glow plug control device for a diesel engine according to the present invention reliably advances the start time of energizing the glow plug, thereby bringing the engine into a state where it can be started. This has the effect of shortening the waiting time until it becomes available.

Further, even if the key is inserted, if there is no intention to start the machine, the power supply is stopped after a predetermined waiting time, thereby automatically avoiding wasteful power consumption.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an overview of a glow plug control device for a diesel engine according to the present invention, FIG. 2 is a circuit diagram showing an embodiment of a glow plug control device according to the present invention, and FIG. 3 is a glow plug according to the present invention. FIG. 4 is a timing chart showing an example of the operation of the glow plug control device according to the present invention; FIG. 5 is a diagram showing the key switch operation portion in a conventional glow plug control device. , FIG. 6 is a timing chart showing an example of the operation of a conventional glow plug control device.

Claims (1)

[Claims] A device for controlling energization to a glow plug when starting a diesel engine, comprising a key insertion detection means for detecting that an operation key is inserted into a key switch for starting the engine; energization control means that receives operating power and starts energizing the glow plug from the time the detection means detects insertion of the key; and a predetermined waiting time from the time the key insertion detection means detects insertion of the key. and an operating power cutoff means for cutting off the operating power of the energization control means when the timekeeping by the clocking means is completed and the key switch is not set to a predetermined operating state. A glow plug control device for a diesel engine, comprising: