JPS5838385A - Apparatus for controlling preheating of engine - Google Patents

Abstract

PURPOSE:To enable to shorten the time required for a glow plug to be heated to a required high temperature after turning an engine switch ON, by starting high-temperature control before turning the engine switch ON. CONSTITUTION:When a key is turned for starting an engine in the state that a switch 35 is closed, a self-holding switch 21 is closed and current is supplied temporarily to all circuts. Here, if the engine temperature is low to such an extent as to require heating of a glow plug 1 and the engine is at rest, a transistor 27 is turned ON by a bias imparted from a an engine temperature detecting circuit 17 via a resistance 29 and a relay 26 is energized to keep a self- holding switch 21 in its closed state. Here, since a comparison circuit 8 produces a high-level output, an electric contact of a main relay 3 is closed and the glow plug 1 can be heated to a required high temperature within a few seconds although the engine key 21 is not turned ON.

Description

[Detailed description of the invention] The present invention relates to a control device for controlling.

In order to perform rapid preheating, it has been proposed to start energizing the preheating valve when the driver's door is opened or closed.
Starting energization in this way when there is no intention to immediately start operation is not preferable from the viewpoint of energy conservation.

Therefore, in the present invention, a changeover switch is provided, and when this switch is operated, for example, it is opened to start rapid preheating, but when it is not operated, preheating is performed from the time the ignition switch is turned on, and by manual operation, The purpose of the present invention is to provide an engine preheating control device that can set in advance whether or not to perform rapid preheating and is useful for energy saving.

Embodiments of the present invention will be described below with reference to the drawings.

In the figure, 1 is a glove lug that generates heat when energized.
They are installed in a diesel engine (not shown) by a known method, and a plurality of them are electrically connected in parallel. As the heating element of this globe lug, one that has a constant positive temperature coefficient of resistance and that reaches its saturation temperature at a voltage of approximately 1/B of the rated voltage is used, and the target heating temperature (for example, 90
The time it takes to reach 0″C) is several seconds (approximately 3 seconds).

Reference numeral 2 denotes a detection resistor for detecting the magnitude of the current flowing through the globe puffer l, which is composed of a resistor with a small temperature coefficient of resistance, a very small resistance value, and a large capacitance. The current flowing through the globe puffer flows through the detection resistor 2 and is influenced by the temperature of the globe puffer itself, so the temperature of the globe puffer can be determined from the magnitude of the voltage drop occurring across the detection resistor 2.

Reference numeral 8 denotes a main relay, which has electrical contacts inserted into an electrical path that directly supplies current from the on-vehicle battery 6 to the globe puffer 1 and the detection resistor 3. Reference numeral 4 denotes a sub-relay, which has an electrical contact inserted into an electrical path that supplies current from the on-vehicle patch g6 to the globe puffer l and the detection resistor 2 via the current limiting resistor 5. The five current limiting resistors provide a stable preheating effect that lowers the heating rate of the globe puffer and at the same time lowers its saturation temperature, compared to when current is supplied directly to the globe puffer. Power is supplied to the globe puffer l through only one main relay, so the globe puffer current is switched in two stages.

The illustrated electrical control circuit for controlling this globe puffer current will be described below.

A differential amplifier circuit generates a signal voltage depending on the potentials of both terminals of the detection resistor 2. A comparison circuit 8 compares the signal voltage with a reference voltage obtained by dividing the voltage applied to the globe puffer 1 and the detection resistor 2 by resistors 9 and 10. The comparator circuit 8 is provided with hysteresis by a resistor 11 and a diode 12, and when the globe puffer temperature exceeds the upper limit value of 900, the rLJ level is set, and when it falls below the lower limit value of 700t-, the rLJ level is set.
A comparison output of HJ level /I/ (open level) is generated. The differential amplifier circuit 7 and the comparator circuit 8 operate by being supplied with power from the constant voltage circuit 18, and when the supply voltage starts up, the comparator circuit 8 is immediately adjusted to the rHJ level μ by the startup circuit 14 consisting of a capacitor and a resistor. and configured to produce an output.

Here, the temperature regulating effect of the globe puffer fish 1 will be explained. Now, the resistance value of Globe Puffer I11 is Ro,
The number is N, the resistance value of the current detection resistor 2 is 18, and the potential of the current detection resistor 8 II is V with reference to the ground potential.
target temperature 9 for the current detection resistor 2 and one globe pug.
The resistance value at 00°C is 1 depending on the temperature coefficient of resistance!
Therefore, if the resistance value set by the voltage dividing resistor 11, 1o VC is kept in the ratio of the above equation, and the resistance value R of the current detection resistor 3 is constant, the comparator circuit 8 will be able to detect the globe puffer temperature at 9O.
When Oζ is reached, the output is inverted to the rLJ level. When current is supplied through the current limiting resistor 5, the output of the comparator 11 is again inverted to the rliJ level when the glow plug temperature corresponds to 700 t- due to the action of the hysteresis provided in the comparator circuit 8.

Here, even if the power supply voltage changes due to cranking, etc., and the temperature of the globe puffer changes as a result, the globe puffer The controlled humidity range ensures that the high temperature condition is maintained.

15 is a relay drive circuit, which receives the output of the comparator circuit 8 and
At HJ level, main relay 3's % [close contact,
This contact is opened when the level is 'J4'. Reference numeral 16 denotes an engine start detector, and a contact 16a closes when the neutral point voltage of an alternator (not shown) driven by the engine rises.
A known voltage regulator is utilized. Therefore, after the engine is started, the electrical contacts of the main relay 8 are kept open by fixing the input of the relay drive circuit 15 to the rl level, regardless of the output of the comparison circuit 8.

1 is an engine temperature detection circuit, which is connected to a temperature-sensitive resistance element 18 attached to the cooling water jacket of the engine, and responds to the resistance value to detect when the engine is at low temperature (cooling water temperature is 40°C).
t″ or less), at (' HJ level, when the engine is at high temperature (
When the cooling water temperature exceeds 40t'), an output of rLJ level μ is produced. Reference numeral 19 denotes a relay drive circuit which closes the electrical contact of the sub-relay when it receives the detection output from the engine temperature detection circuit 17 and is at the rHJ level, and opens this contact when it is at the rLJ level. Even after the engine is started, the globe puffer l is energized through the electrical contacts of the lag relay 4 and the current limiting resistor 6 to keep it in a heat-generating state until the engine is sufficiently warmed up.

The above-described circuit operates when the vehicle battery 6 is closed when the engine key switch 20 or the self-holding switch 21 is closed.
It operates with more power. In other words, the key switch go supplies power from the ignition terminal (1G) to other on-vehicle electrical loads, while supplying the circuit operating voltage +V via the diode gg.
supply. Further, the self-holding switch 31 supplies the circuit operating voltage +V via the diode 28. The diode 2B has the role of preventing power from being supplied to other electrical loads from the self-holding switch z1, and the diode 23 has the role of preventing the holding current from the key switch 80 from being supplied to the self-holding switch 21.

The engine key switch 20 is closed while the engine is running (however, when the engine is started and the engine temperature is sufficiently high, the circuit operation is stopped).

), but the self-holding switch 21 is the engine key switch 2
The closed state is maintained only for a specific period starting from the operation preparation operation before the 0 is turned on.

The self-holding switch 21 is configured as a normally open contact that is attracted by the holding coil 24, and the starting current flowing through the holding coil 41V24 is applied by the operation readiness detection switch g6, and the holding current is applied to the electric contact of the relay 26. and a manual switch 35. The driving readiness detection switch g6 is built into the keyhole of the driver's door of the vehicle, and when the movable contact comes into contact with the contact 515A located at the middle position of the rotation range of the key, the holding coil A/24 is energized and self-activated. Close the hold switch 21. Once the self-holding switch 21 is closed, the relay 26 is energized and the holding current of the holding coil 24 continues to flow through its electrical contacts, causing the self-holding switch 21 to close.
The closed state of is maintained.

Is the coil of relay 86 transistor 2? The presence or absence of self-holding is determined by the on/off of this transistor 27, which is connected to this transistor 27. Furthermore, the contact of the relay 26 is a manual switch 85.
Only when the switch 86 is closed, it is possible to determine whether or not the transistor 87 is self-holding. The switch 35 is installed near the driver's instrument panel, and the driver opens it when getting out of the vehicle.

By setting it in the closed state, it is possible to control whether or not the above-mentioned self-holding occurs.

When the switch 86 is closed, the conditions for determining self-holding in the transistor 27 are (11) engine temperature, (2) whether or not the engine is started, (3) temperature of the globe puffer l, and (4) operation readiness detection. The elapsed time since the switch 25 was turned off is the 04 condition.Among these conditions, the first three are (1) the engine temperature detection circuit 17, (8) the start detector 16, and @) the signal from the comparison circuit 8. The level signal described above is used.

For the last (4) elapsed time, the level signal from the timer circuit 28 is used. The timer circuit 28 is composed of an OR time constant circuit and is operated by the constant voltage output +vc of the constant voltage circuit 34 which receives the operating voltage +■ when the self-holding switch 21 (engine key switch 20) is opened. When the self-holding switch 21 closes due to the operation of the operation preparation detection switch 25, the constant voltage output terminal vo of the constant voltage circuit 29 starts up, and the timer circuit g8 initially has the rHJ level p, but after a few seconds, the rLJ level μ. produces an output of In the timer circuit 28, the OR time constant circuit is set to a discharging time constant of several tens of seconds in contrast to the charging time constant of several seconds.

The level signals given to the control input terminals of the transistors 2.7 to determine self-holding must be applied to the voltage-dropping resistors in order to achieve their purpose without interfering with each other. 19 and diode groups 30 and 31.8ffi.

Therefore, if the switch 85 is left in an open state, even if the transistor 27 turns on, the self-holding current is refreshed in the switch 86, so that self-holding is not achieved.

The operation of the entire device will be explained based on the above configuration and circuit functions. The switch 85 is currently in the closed state, and when the key is inserted into the keyhole and turned in order to drive the vehicle that has been left unattended for a long time, the self-holding switch s1 is closed and power is temporarily supplied to each circuit. At this time, the engine temperature is low enough to require heating of the glow puffer fish l (40°C or less in this example) (therefore, the output a rl level fi7 of the engine temperature detection circuit 17), and of course the temperature of the globe puffer fish l itself is low. The temperature is low (the output of the comparator circuit 8 is at rHJ level (however, open level A/)), and the engine is stopped (the output from start detection 1!16 is at rHJ level/L/ (however, open level/L/) ), the transistor 27 is biased from the engine temperature detection circuit 17 via the resistor 29 and turned on, energizing the relay z6 and holding the self-holding switch 21 in the closed state 11.

Therefore, since the output of the comparator circuit 8 is at the rl level,
The electrical contacts of the main relay 8 are closed, and therefore the globe puffer l is rapidly heated and reaches a temperature of 900℃ in about a few seconds, even though the engine key switch 20 is not turned on. At this time, the "H" level output of the engine temperature detection circuit 17 also closes the electrical contacts of the sub-relay 4, but no current flows while the electrical contacts of the main relay 8 are closed.

When the globe puffer temperature reaches 900° C., the output of the comparator circuit 8 is inverted and becomes the rLJ level μ. Therefore, the bias of the transistor 27 is fixed at the rLJ level via the diode 81, and the transistor 27 is turned off. Self-holding switch at this point! 1 is released and the device stops operating.

If the engine key switch 20 is turned on before the glow plug temperature reaches 900t', or if the engine key switch 20 is turned on soon after the glow plug temperature reaches 900t' and the self-holding switch 21 is released,
When turned on, the circuit continues or restarts to control the supply of electricity to the globe puffer 1. In this case, until the engine starts, the comparator circuit 8 is set at 90% of the glow plug temperature.
The output is inverted between 0t'' and ?OOt, and the electrical contacts of the main relay 3 are opened and closed to control the globe puffer l to be maintained at a high temperature.The driver should take appropriate timing. The key switch 20 can be turned on to the starting terminal in advance or in accordance with the lighting of the indicator lamp s3.

The sub-relay command preheats the engine until the engine temperature reaches a predetermined value.

The advantage of this device is that by starting this high temperature control before the engine key switch 20 is turned on, the time from when the carrot switch 20 is turned on until the globe puffer temperature reaches the desired high temperature state can be reduced. This can be done by reducing it to zero or making it very short. This time can be further reduced by preventing the driver from taking an unnecessarily long time from unlocking the door key to operating the engine key switch.

An advantage of the present invention is that by opening the manual switch 8b in advance, the glove puffer can be used even during the operation preparation operation.
Therefore, when the driver judges that such rapid heating is not necessary, such as in the summer or when restarting the engine after a while after getting off the vehicle, the driver should not turn off the rapid heating of the engine. This also prevents power wastage. Of course, even in this case, engine key switch 2
6, power is applied to the globe puffer l and temperature control is performed.Furthermore, the device described here can be used when the driver does not intend to start the engine immediately after unlocking the door key,
When the engine condition does not require rapid heating of the globe puffer l, unnecessary operation is prevented.

1st K. Once the globe puffer temperature reaches the desired high temperature state aK, self-holding is released and the engine key switch 20
Until the power is turned on, the power supply is stopped and the power supply is on standby. Once heated, the glow plug 1 gradually cools down due to thermal inertia, but since the comparator circuit 8 and its peripheral circuits are not supplied with power, the main relay 8 and sub-relays are not operated.

Second, when the engine temperature is already high, self-holding is not performed from the beginning.

Third, the engine cannot hold itself when it is already started.

Fourth, during self-holding, if the glow plug temperature does not reach a predetermined high temperature state even after a predetermined period of time has elapsed, the timer circuit 3
Self-holding is canceled by the 1-L level output of 8,
If a failure occurs in another circuit, especially when a failure occurs in the comparator circuit 8 and its preceding stage and the comparator circuit 8 is no longer able to produce the [LJVV output], a failsafe is achieved.

Although one embodiment of the present invention has been described above, the present invention can also be implemented with the following modifications added.

In order to change the engine temperature for controlling the fl+ sub-relay 4 and the engine temperature for controlling self-holding, two engine temperature detection circuits 19 may be provided.

(Note) In order to automatically drive the engine starting motor, the rLJ level μ output of the comparator circuit 8 and the engine key switch 200
It is possible to add a relay circuit that closes the electric switch of the starting motor using the logical AND condition of "turning on" and "turning on".

In accordance with the button operation readiness detection, the sub relay 4 instead of the main relay 8 may be activated to preheat the glow plug 1. Therefore, with the output of the self-holding control function register 27,
While the self-holding switch 21 is closed, the voltage dividing ratio of the voltage dividing resistors 9 and 10 that provides the comparison reference voltage of the comparator circuit 8 is changed only during the self-holding period, and when the globe puffer temperature reaches, for example, about 600 t- , IL to comparison circuit 8.
Self-holding may be released by generating a level output.

(4) As a means for detecting preparation for driving, a seat switch, etc., which responds to the driver's sitting down while driving, may be used in place of the switch g5, which responds to the operation of the door key.

(5) The present invention can also be applied to an apparatus that operates a timer circuit based on the detection of preparation for operation, and uses the timer output to rapidly heat the rug -7'' lug.

(A digital computer (microcomputer) may be used in part.

As described above, the present invention has the excellent effect of significantly shortening the preheating time before starting the engine, and also eliminating unnecessary energization of the glow plug when there is no intention to operate the engine. .

[Brief explanation of drawings]

The drawing is an electrical wiring diagram showing an embodiment of the present invention. l-globe puffer, 8.-resistance for current detection, 3.
- main relay (electrical switch), 8 - ratio l112 circuit, 16 - starting detector for status detection, 21... - self-holding switch, z6 - switch for operation readiness detection,
36-Manual switch. Representative Patent Attorney Takashi Okabe

Claims (1)

[Scope of Claims] (1) - A first means for detecting a driving operation of one engine, a second means for detecting a preparatory operation of the engine, and the first means for detecting a driving operation of the engine.
an electric control device for starting the operation of a preheating device mounted on the engine in response to the second means; and a manual switch provided for substantially disabling the detection operation of the eighth means. An engine preheating control device comprising: (8) The electric control device includes a holding circuit that performs electrical self-holding in response to the ninth means, and is configured such that the manual switch prohibits the self-holding. An engine preheating control device according to claim 1.