JPS6149509B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a diesel engine auxiliary device, and in particular, an object of the present invention is to provide a diesel engine auxiliary device that can suppress the generation of noise during idling.

It is well known that a diesel engine is characterized by large combustion noise at low speeds and low loads. The main reason for this is the ignition delay at low speeds and low loads. There is also a tendency for the ignition delay to result in incomplete combustion, resulting in an increase in harmful gas components in the exhaust gas.

An object of the present invention is to provide a diesel engine auxiliary device that compensates for ignition delay at low speeds and low loads, thereby reducing combustion noise and harmful gas components in exhaust gas.

In this invention, an idling state is specified as a condition for low speed and low load, and by detecting the idling state, power is supplied to, for example, a glow plug installed in a sub-combustion chamber, and by heating it, the sub-combustion The system heats the mixture of indoor air and fuel, and this heating makes it easier to ignite the mixture, compensating for the ignition delay during idling, reducing combustion noise, and suppressing the increase in harmful gas components in the exhaust gas. This is what I did.

An embodiment of the present invention will be described in detail below with reference to the drawings.

The figure shows one embodiment of the invention. In the figure, 1 is a battery, 2 is a key switch, and 3 is a glow plug. The glow plug 3 is originally intended to heat a gas mixture of air drawn into the auxiliary combustion chamber and fuel injected into this air when starting the engine, making it easier to ignite and start the engine. It is designed to help you reach the goal. Therefore, in the preheating position of the key switch 2, the movable contact 2a of the key switch 2 contacts the operating contact 1G and the preheating contact PS, and supplies heating power to the glow plug 3 through the preheating contact PS. The glow plug 3 has a heater 3a on its head.
Here, the resistance value of this heater 3a is set to be smaller than the rated value, for example, about the rated value at the set temperature.
The case where the value is set to 1/2 or less will be explained.
Here, the rated value of the heater 3a is defined as follows. In other words, glow plug 3 generally has a temperature of 800℃ to 900℃.
It is required to be heated to ℃. Conventionally, the resistance value of the glow plug 3 has been selected to be stable at the rated temperature of 800° C. to 900° C. when voltage is applied from the battery 1. This resistance value will be referred to as the rated value here, and in this invention, the glow plug 3
Select the resistance value to be smaller than this rated value, for example, to have a positive temperature coefficient of resistance that is less than 1/2 at room temperature and about 1/2 at the set temperature, and
When the rated temperature reaches 800°C to 900°C, the glow plug 3
A case is shown in which a protective resistor 4 is connected in series and the heating current is reduced by inserting the protective resistor 4 so that the glow plug 3 is stabilized at its rated temperature. This configuration has the advantage of shortening the preheating time.

A determination circuit 6 detects whether the glow plug 3 has reached the rated temperature. That is, the glow plug 3 is connected to one side of a bridge formed by resistors 7, 8, and 9, and the resistance of the glow plug 3 forming one side of this bridge increases with temperature, and when the set temperature is reached, the voltage increases. is compared by the judgment circuit 6, and the signal is supplied to the relay 11 through the amplifier 10 as necessary, and by controlling the relay 11 to turn off, the protective resistor 4 is connected to the glow plug 3.
By connecting this resistor 4 in series with the glow plug 3, the current flowing through the glow plug 3 is reduced, and the temperature of the glow plug 3 is stabilized at the rated temperature of 800°C to 900°C. In addition, in response to the signal from the judgment circuit 6, for example, an indicator lamp (not particularly shown) is lit, and the lighting of the indicator lamp indicates the completion of preheating, and at this point, by switching the key switch 2 to the starting position, Since the glow plug 3 has reached the rated temperature, starting can be achieved easily and in a short time.

The present invention provides an idling detection circuit 12 for detecting an idling state and a glow plug 3 for detecting an idling state in a diesel engine equipped with a starting assist device using such a glow plug 3.
A determination circuit 6 determines whether the temperature of the glow plug 3 is higher or lower than a set temperature, for example, a rated temperature, and if the temperature of the glow plug 3 is lower than the set temperature in an idling state, a rapid heating current is applied to the glow plug 3 to make it higher than the set temperature. In this case, a current control circuit 13 provides a current to maintain the set temperature of the glow plug 3, and an electromagnetic actuator 15 operates based on the detection output of the idling detection circuit 12 to throttle the intake shutter 14.
and

The idling detection circuit 12 can be composed of, for example, three switches 12a, 12b, and 12c. Switches 12b and 12c are connected in parallel with each other, and switch 12a is connected in series with the parallel circuit.
is connected. Switch 12a is a switch that is turned on when the accelerator pedal is not depressed, switch 12b is a switch that is turned on when the clutch is disengaged, and switch 12c is a switch that is turned on when the gear is in neutral. show. Therefore, when the following conditions are met: the accelerator pedal is not depressed, the clutch is disengaged, or the gear is in neutral, it is determined that the idling state is present, and the circuit connects the battery 1 to the current control circuit 13 and the electromagnetic actuator. 15 is supplied with power.

The current control circuit 13 includes a switch circuit 13a such as a Schmitt trigger circuit, an amplifier 13b that amplifies the output of the switch circuit 13a, and a relay 13c that is turned on and off by the output of the amplifier 13b. . relay 1
3c is connected between the output side of the idling detection circuit 12 and the connection point of the resistors 9 and 8 forming the bridge. The relay 13c is a normally closed contact and is kept on when the glow plug 3 is idling and the temperature has not reached the set temperature. Therefore, immediately after the idling state, voltage is supplied to the connection point between the resistors 8 and 9 through the idling detection circuit 12 and the relay 13c, and power is supplied to the glow plug 3. At this time, since the resistor 9 that constitutes the bridge is only connected in series to the glow plug 3, the current flowing through the glow plug 3 is more than twice the current flowing through a conventional glow plug, and the glow plug 3 rapidly heated. Therefore, within a very short time after entering the idling state, the glow plug 3 reaches its rated temperature of 800℃ to 900℃.
This heats the gas mixture in the sub-combustion chamber. Therefore, it becomes easier to ignite the gas mixture, and the ignition timing is not delayed. In other words, ignition is achieved immediately after the piston passes the top dead center, and combustion noise at low speeds and low loads can be reduced. Further, since the mixed gas is heated and ignited by the glow plug 3, complete combustion is achieved, and an increase in harmful gas components in the exhaust gas can be suppressed.

When the temperature of the glow plug 3 reaches the rated temperature of 800°C to 900°C, the comparator 6 detects this and the potential of its output is reversed. This inverted output is supplied to the Schmitt trigger circuit 13a.
The output of is amplified by amplifier 13b and relay 13
Control c off. Therefore, the power supply to the glow plug 3 is cut off, and the temperature of the glow plug 3 decreases. When the temperature of the glow plug 3 becomes lower than the rated value of, for example, 800° C., the output of the comparator 6 returns to, for example, L logic, and the output of the switch circuit 13a also returns to L logic. As a result, the relay 13c returns to the on state and energizes the glow plug 3 again to heat it. Therefore, the temperature of the glow plug 3 rises again, and when the temperature exceeds the rated value of 800°C, the output of the comparator 6 rises to H logic, which inverts the output of the switch circuit 13a to H logic, and turns off the relay 13c. do. In this way, the relay 13c is turned on and off to stabilize the temperature of the glow plug 3 at around the rated temperature of, for example, 800°C during idling, and heat the mixture of air and fuel sucked into the auxiliary combustion chamber during idling. By this heating, it is possible to compensate for the delay in the ignition point and maintain the ignition point at an appropriate level even when the engine is idling, thereby suppressing an increase in combustion noise during idling. In this embodiment, the relay 16 is turned on by the detection output of the idling detection circuit 12, and a resistor 7a is connected in parallel to the resistor 7 constituting the bridge to reduce the voltage generated in the resistor 7. A case is shown in which the temperature at which the glow plug 3 is stabilized is lower than the rated value, for example, about 600 to 700°C.

On the other hand, in the present invention, the detection output of the idling detection circuit 12 supplies power to the electromagnetic actuating device 15 such as an electromagnetic solenoid in the idling state, and operates the electromagnetic actuating device 15 to operate the intake shutter 1.
I'm trying to narrow it down to 4. This intake shutter 14 is provided to control the amount of air taken into the engine, and is normally used before starting the engine to control the amount of air taken in to facilitate starting. It will be done. In this invention, when the intake shutter 14 is in an idling state, the intake amount of throttled air is reduced, thereby reducing the maximum pressure inside the cylinder. By lowering the maximum pressure inside the cylinder during idling in this manner, the amount of combustion noise generated can be further reduced.

Furthermore, this embodiment shows a case where the generator is configured to compensate for a decrease in the power generation capacity of the generator in an idling state. That is, when the idling detection circuit 12 detects that the idling state is detected, the relay 17 is turned on, and by turning on the relay 17, the excitation current supplied to the field winding 19 of the generator 18 is transferred to the resistor 20. The excitation current value is increased to increase power generation capacity. Reference numeral 21 indicates a regulator, and the electric power generated by the rotor 22 is rectified by a rectifier circuit 23, and the rectified output is stabilized at a constant voltage by the regulator 21, and the stabilized output is output by the key switch 2.
It is supplied to the battery 1 through the operating contact 1G of the battery 1, and the surplus is supplied to the electrical components in operation while being charged.

Further, in this embodiment, taking into account that the engine load increases due to the increase in the power generation capacity of the generator 18, when the idling detection circuit 12 detects the idling state, it supplies power to the actuator 24, and this actuator 24 especially Although it is not shown, the fuel pump's flow rate adjustment lever is operated to automatically increase the amount of fuel supplied to prevent the engine from becoming extremely slow.

As explained above, according to the present invention, since the glow plug 3 is heated and the mixed gas is heated during idling, there is no ignition delay, and therefore the combustion noise of the diesel engine during low speed rotation can be reduced. Furthermore, since complete combustion is achieved, harmful gas components in the exhaust gas can be reduced. Furthermore, since the intake shutter 14 is throttled based on the detection output of the idling detection circuit to reduce the maximum pressure in the cylinder, combustion noise can be further reduced by this.

Therefore, according to the present invention, the noise of the diesel engine during low speed rotation can be reduced, and a diesel engine with low noise can be obtained.

In the above-mentioned embodiment, the power supplied to the glow plug 3 is controlled intermittently in the idling state to control the temperature of the glow plug 3 to a constant temperature, but the current control circuit used at startup may be changed as is. You can also use it. In other words, one end of the idling detection circuit 12 is connected to the key switch 2.
Connect the operating contact IG to the operating contact IG, and connect the other end to the preheating contact PS.
While the temperature of the glow plug 3 is lower than the set value, current is supplied directly to the bridge including the glow plug 3 through the relay 11. When the glow plug 3 reaches the set temperature, the relay 11 is turned off and current is supplied to the bridge via the protective resistor 4. It may be configured to supply With this configuration, the switch circuit 13a, amplifier 13b, and relay 13c can be omitted, and the circuit can be simplified.

[Brief explanation of the drawing]

The figure is a connection diagram showing one embodiment of the present invention. 1: Battery, 2: Key switch, 3: Glow plug, 6: Judgment circuit, 12: Idling detection circuit, 13: Current control circuit, 14: Intake shutter, 15: Electromagnetic actuator.

Claims (1)

[Claims] 1. In a diesel engine having a glow plug, an idling detection circuit detects a low speed and low load state after one run, and a determination circuit determines whether the temperature of the glow plug is above or below a set temperature. , current control means that applies a rapid heating current to the glow plug in the idling state and when the determination result of the determination circuit is below the set temperature, and applies a current that causes the glow plug to maintain a constant temperature when the temperature is higher than the set temperature;
A diesel engine auxiliary device comprising: an electromagnetic actuator that throttles an intake shutter when the idling state detection circuit detects an idling state.