JPS58200080A - Glow plug operating apparatus for diesel engine - Google Patents

Abstract

PURPOSE:To improve the performance of warmping up an engine and to thereby prevent the production of white smoke due to knocking, by connecting a sensor for detecting the temperature of exhaust gas to each cylinder of the engine, and resuming ''after-glow'' when the temperature of exhaust gas of some cylinders has become lower than a prescribed value after completion of ''after-glow''. CONSTITUTION:When the temperature of exhaust gas of a cylinder that has caused abnormal combustion is lowered and the value of resistance of a sensor 20 is varied, a comparator 21 connected to the sensor 20 produces an output ''1'' in response to the deviation to a reference voltage, and an OR-element 23 also produces an output ''1''. Further, when an ''after-glow'' completion signal from an ''after-glow'' timer 11 and an output signal of the OR-element 23 are applied to a second ''after-glow'' timer 13, the output of the timer 13 becomes ''1'' and a transistor 14 is energized. At the same time, a glow plug 1 is also energized. On the other hand, when combustion becomes normal, the potential of the temperature sensor 20 is raised and the outputs of all of the comparators 21 become ''1'', and current supply to the glow plugs 1 is stopped.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a glow plug actuation device for a diesel engine.

In order to improve startability at low temperatures in diesel engines equipped with an auxiliary combustion chamber, a glow plug adjacent to the auxiliary combustion chamber is operated (generated heat) to preheat the engine before starting. In order to improve the warm-up performance after starting, some engines operate the glow plug even after starting to perform so-called afterglow. The glow plug temperature characteristics of this product are shown in Figure 1, for example (
Nissan Motor Co., Ltd.: Service Bulletin No. 450, issued in January 1981, ``Datsun Motor Bird JP, refer to 61) -0 However, even in those models that perform afterglow in this way, some cylinders may be damaged during extremely cold weather. Once ignition combustion has started, a misfire may occur, and conventional systems are unable to deal with such situations, resulting in poor warm-up performance and the generation of knocking and white smoke.

The present invention was developed in view of such conventional problems, and detects the exhaust temperature of each cylinder after startup, and detects the exhaust temperature of any cylinder due to the occurrence of abnormal combustion such as misfire after completion of afterglow after startup. The purpose of the present invention is to provide a glow plug actuating device for a diesel engine that further performs afterglow when the temperature drops below a certain temperature, thereby improving warm-up performance and preventing generation of non-king, white smoke, etc. do.

The present invention will be explained below based on illustrated embodiments.

In FIG. 2 showing one embodiment, glow plugs 1 connected in parallel for each cylinder are connected through a contact 2a of a first relay 2, a contact 3a of a second relay 3 connected in parallel, and a dropping resistor 4. and is connected to the battery 5.

Reference numeral 6 denotes a timer unit, which includes internal circuits such as various timers to be described later and input/output terminals T1 to T.

That is, the lamp timer 7 has its input terminal connected to the T1 terminal, and its output terminal connected to the base terminal of the transistor 8. The collector terminal of the transistor 8 is connected to the T2 terminal, and the emitter terminal is grounded. Preheat timer 9
has two input terminals connected to the T3 terminal and T4 terminal, respectively, and an output terminal connected to the T3 terminal through the coil 10b of the relay 10.
Connected to el terminal. The contact 10a of the relay 10 is T
Connected between the 5 terminal and the T6 terminal. The first afterglow timer 11 has four input terminals, T7 and T7, respectively.
1 terminal, T4 terminal, and one input terminal of a second afterglow timer 13 to be described later, and its output terminal is connected to the base terminal of the transistor 12. The transistor 1
2, the collector terminal is connected to the Te terminal, and the emitter terminal is grounded. The second afterglow timer 13 is 3
It has two input terminals, one of which is the first input terminal as described above.
is connected to the input terminal of the afterglow timer 11, and the others are connected to the T4 terminal and the T9 terminal, respectively. Further, the output terminal of the timer 13 is connected to the base terminal of the transistor 14. The collector terminal of the transistor 14 is connected to the Te terminal, and the emitter terminal is grounded. T2. terminal and T1. The terminals are directly connected inside the timer unit 6.

Further, each of the terminals T1 to T11 of the timer unit 6 is connected outside the unit 6 as will be described later. A water temperature sensor (thermistor) 15 that detects T is connected. A glow lamp 16 is connected between the T2 terminal and the T5 terminal. T
A charge lamp 17 is connected between the third terminal and the T5 terminal, and the T3 terminal is grounded via a regulator switch 18 of the alternator. T4 terminal is glow plug
grounded through. The T5 terminal is connected to the anode of the battery 5 via the ON contact of the ignition switch 19. The T6 terminal is grounded via the coil 2b of the first relay 2. The T7 terminal is connected to the anode of the battery 5 via the start (ST) contact of the ignition switch 19. The T@ terminal is connected via the coil 3b of the second relay 3 to the ON contact of the ignition switch 19, and hence to the T5 terminal.

Further, an exhaust temperature sensor 20 for detecting the exhaust temperature is provided at the exhaust port of each cylinder of the engine (not shown), one end of which is connected to the T+6 terminal, and the other end is connected to the respective comparator 21.
connected to one input terminal of the

Further, the other input terminal of each comparator 21 is connected to T via a resistor 22.
, o terminals, and the output terminals of the comparator 21 are connected to the OR terminals, respectively.
The input terminals of the elements 23 are respectively connected to the input terminals of the elements 23.

The output terminal of the ORs child 23 is connected to the T9 terminal.

Next, the operation of such a device will be explained.

When the ignition switch 19 is set to the ON position, the voltage of the battery 5 is applied to the T5 terminal of the timer unit 6. At this time, since the engine is stopped, the regulator switch 18 is ON, and therefore the potential of the T3 terminal is "0", so the output of the preheat timer 9 is "0".Therefore, the coil 10b of the relay 10 is is energized and its contact 10a is closed, and the output from the Te terminal energizes the coil 2b of the first relay 2 and closes its contact 2.
Since a is closed, the glow plug 1 is energized.

Therefore, the glow plug 1 starts preheating the engine. At this time, the second afterglow timer 11 also has an output of "1" because the potential of the T7 terminal is "0", and the coil 3b of the second relay 3 is energized and the contact 3
a is closed, but since the contact 2a of the first relay 2 is closed, the voltage of the battery 5 is directly applied to the glow plug l, and the glow plug 1 is heated to a high speed and preheated in a short time. Complete.

On the other hand, the output of the lamp timer 7 is "1" due to the resistance value of the water temperature sensor 15 corresponding to the cooling water temperature, and the transistor 8 is turned on, so the glow lamp 16 is energized and lit, and during the preheating wait time. Something is displayed.

When the cooling water temperature rises due to preheating and the resistance value of the water temperature sensor 15 changes to a predetermined value, the output of the lamp timer 7 becomes "0", the transistor 8 becomes non-conducting, and the glow lamp 16 turns off. Turn off the lights.

When the completion of preheating is sensed by turning off the glow lamp 16 and the ignition switch 19 is switched to the start position, the starter is driven and the engine is cranked, so the regulator switch 18 is turned off. Therefore, a high potential is applied to the preheat timer 9 through the T3 terminal, and the output of the preheat timer 9 becomes 1''.Therefore, the current to the coil 10a of the relay 10 is cut off, and the contact 1
0a is opened, the current to the coil 2b of the first relay 2 is also cut off, and the contact 2a is opened.

On the other hand, as the voltage of the battery 5 is applied from the ST contact to the T7 terminal to the first afterglow timer 11, the output of the timer 11 becomes "0" and the transistor 1
2 becomes non-conductive, the coil 3b of the second relay 3 is also de-energized and the contact 3a opens. Therefore, the glow plug 1 is not energized and preheating is stopped. In this state, start the engine by cranking, and press the ignition switch 19.
When it is returned to the ON position, the application of voltage from the T7 terminal to the first afterglow timer 11 is stopped, so that the output of the timer 11 becomes "1".

Therefore, the transistor 12 becomes conductive and the coil 3a of the second relay 3 is energized, and the contact 3a is closed and the glow plug 1 is energized via the dropping resistor 4. That is, afterglow is performed by the glow plug 1 with a lower calorific value than during preheating.

The operation up to this point is the same as the conventional one. Next, a case will be described in which abnormal combustion such as misfire occurs in some cylinders after completion of afterglow by the first afterglow timer 11. At this time, the exhaust temperature of the cylinder where abnormal combustion occurred decreases,
The resistance value of the exhaust gas temperature sensor 20 provided corresponding to the cylinder changes greatly. As a result, for example, the exhaust temperature
℃ or less, the comparator 21 connected to the sensor 20 outputs "1" due to the difference between the potential input from the sensor 20 and the reference potential input from one end of the resistor 22.
Then, the output of the OR element 23 inputting this signal becomes “1”.
''. Then, when the afterglow completion signal from the afterglow timer 11 and the signal of 1 from the OR element 23 are input to the second afterglow timer 13, the output of the timer 13 becomes ``1'' and the transistor 14 conducts, the coil 3a of the second relay 3 is energized, the contact 3a is closed, and the glow plug 1 is connected via the dropping resistor 4.
is energized and afterglow resumes. The afterglow normalizes the combustion in the cylinder where the abnormal combustion occurred and raises the exhaust temperature, which increases the potential of the exhaust temperature sensor 20 corresponding to this, and the outputs of all the comparators 21 become "O".
'', the output of the OR element 23 becomes ``0'', the output of the second afterglow timer 13 becomes ``O'', the transistor 14 becomes non-conductive, the power supply to the glow plug 1 is cut off, and afterglow stops.

In this way, by detecting the exhaust temperature and restarting afterglow, even if abnormal combustion occurs, it can be quickly normalized, improving warm-up performance and suppressing knocking and white smoke. .

Note that in the above embodiment, the second afterglow timer 1
The temperature characteristics of the glow plug when No. 3 is activated are shown in FIG.

As explained above, the present invention is configured to detect the exhaust gas temperature of each cylinder and restart the afterglow by the glow plug when a cylinder has a large decrease in exhaust temperature, so that combustion in the golden cylinder can be quickly carried out. The engine can be normalized, suppressing knocking, white smoke, etc., and improving warm-up performance. This also improves fuel efficiency.

[Brief explanation of drawings]

Fig. 1 is a diagram showing glow plug temperature characteristics in a conventional glow plug operating device, Fig. 2 is a circuit diagram showing an embodiment of the present invention, and Fig. 3 is a diagram showing glow plug temperature characteristics of the same embodiment. It is a line diagram. 1...Glow plug 2...Second relay 3...
・Third relay 5...Battery 6...Timer unit 9...Preheat timer 11...
・First afterglow timer 13... Second afterglow timer 19... Ignition switch, 20... Exhaust temperature sensor 21... Comparator 22... Resistor 23... OR element patent application Person Nissan Motor Co., Ltd. Representative Patent Attorney Fujio Sasashima

Claims (1)

[Claims] A glow plug operating device for a diesel engine that is equipped with a glow plug in the combustion chamber and operates the glow plug for a period of time depending on the operating conditions before and after starting the engine to perform preheating and afterglow. An exhaust temperature sensor is provided to detect the exhaust temperature, and when the exhaust temperature sensor detects that the exhaust temperature of at least some of the cylinders falls below a predetermined value after the end of the afterglow, the glow plug is activated to restart the afterglow. A glow plug actuating device for a diesel engine, characterized in that a means is provided.