JP2557360Y2 - Exhaust brake control circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an exhaust brake control circuit used for an automobile.

[Conventional technology]

As an engine brake of an automobile having a reciprocating internal combustion engine, a butterfly valve (hereinafter referred to as an electromagnetically driven valve in a driving mode) is provided in an exhaust pipe for discharging exhaust gas from an engine combustion chamber, and the exhaust system is closed by the electromagnetically driven valve. There is an exhaust brake that reduces vehicle speed.

In addition, when the exhaust system is closed by the electromagnetically driven valve at the time of low-temperature start, the startability is improved, so-called warm-up operation time is shortened, and white smoke exhaust due to incomplete combustion at the time of low-temperature start is suppressed. Therefore, there is a control called a cold start control for arbitrarily performing the same state of the electromagnetically driven valve as the state of the exhaust brake at the time of starting at a low temperature.
This control uses a cold start
This is done with a switch.

The exhaust brake and cold start control are performed by, for example, an electric circuit shown in FIG.

In the figure, reference numeral 1 denotes an electromagnetically driven valve that opens and closes an exhaust pipe, and reference numeral 2 denotes an electromagnetic coil that drives the electromagnetically driven valve 1. One end of this electromagnetic coil 2 is grounded, and the other end is connected in series in the order of accelerator switch SW1, exhaust switch SW2, clutch switch SW3, fuse 3, starter switch SW4, and fusible link 4. The last end is connected to the positive electrode of the battery 5 as a power supply.

 The negative electrode of the battery 5 is grounded.

In the above description, the accelerator switch SW1 is a switch interlocked with the operation of the accelerator pedal, and turns off when the accelerator pedal is depressed, and turns on when the foot is released from the accelerator pedal. Therefore, it is on when idling.

The exhaust switch SW2 is a manual lever switch operated by the driver, and is turned on when it is desired to apply the exhaust brake and turned off when it is not desired.

The clutch switch SW3 is a switch interlocked with the clutch pedal, and turns off when the clutch pedal is depressed, and turns on when the foot is released from the clutch pedal.

Therefore, in this circuit, the foot switch is released from the accelerator pedal and the clutch switch, and the exhaust switch SW2
Is turned on, the electromagnetic coil 2 is energized, the electromagnetically driven valve 1 is driven, the exhaust pipe is closed, and the exhaust brake is applied.

A pilot lamp that simultaneously indicates the exhaust brake status
PL lights up.

On the other hand, the other end of the line branched from the line between the clutch switch SW3 and the fuse 3 is a cold start line.
Connected to contact B of switch SW5, and ground L of the switch
Is connected through a backflow prevention diode 6 to the middle of the line connecting the accelerator switch SW1 and the electromagnetic coil 2.

With the above circuit, even if any one of the accelerator switch SW1, the exhaust switch SW2, and the clutch switch SW3 is off, the cold start switch SW5
Is turned on, the contacts B and L are connected, the switch is turned on, the electromagnetic coil 2 is energized, and the electromagnetically driven valve 1 closes the exhaust pipe. That is, even if the operation mode of the electromagnetically driven valve 1 is the same as that of the exhaust brake state, the cold start control having completely different effects can be realized.

This state is maintained until the cold start switch SW5 is turned off.

On the other hand, in an automobile equipped with an automatic transmission, under the condition that the transmission is in a power transmission state, when the engine speed is equal to or lower than a constant low speed of, for example, 1000 rpm, cooling by an oil cooler is performed because of the low speed. In addition to the tendency of insufficient capacity, the use of an exhaust brake has been said to result in damage to the transmission due to a sudden increase in oil temperature due to so-called torque converter slip. For this reason, as a control condition of the automatic transmission, a measure is required to prevent the exhaust brake from being effective in a certain low-speed rotation region.

[Problems to be solved by the invention]

For example, in an automobile having an electric circuit as shown in FIG. 2, even if the automobile is running in a certain low-speed rotation range required as a control condition of the automatic transmission, an accelerator switch SW1, an exhaust switch SW2, If all of the clutch switches SW3 are turned on, there is a problem that the exhaust brake functions and the automatic transmission is damaged.

The present invention provides an exhaust brake control circuit that prevents the exhaust brake function from operating as long as the engine is in a predetermined low-speed range while driving a vehicle, suppresses a rapid rise in oil temperature due to torque converter slip, and protects the transmission. The purpose is to do.

[Means for solving the problem]

In order to achieve the above object, an exhaust brake control circuit of the present invention includes an exhaust pipe for an exhaust pipe of an internal combustion engine of a vehicle equipped with an automatic transmission in which a driving force of the internal combustion engine is transmitted through a fluid coupling. An electromagnetic brake valve that opens and closes, and a drive circuit for the electromagnetic drive valve, the exhaust brake control circuit having at least a clutch switch that opens the drive circuit when the clutch pedal is operated and closes the drive circuit when the clutch pedal is not operated, A rotation sensor for detecting a rotation speed of the internal combustion engine, a control switch connected in series with the clutch switch and provided in the drive circuit, and a rotation switch for decelerating the internal combustion engine by closing the electromagnetically driven valve. When the engine speed detected by the sensor is higher than a predetermined speed, the control switch Close one, the engine rotational speed and a controller to open the control switch when it is determined that it has decreased below a predetermined rotational speed.

[Action]

The engine speed determination unit compares the engine speed with a preset reference value. If the engine speed drops to this reference value, the control switch is turned on and the solenoid valve is opened.

〔Example〕

In FIG. 1 shown for explaining the embodiment, the same reference numerals as those in FIG. 2 are used for those having no possibility of confusion in order to avoid complexity.

In FIG. 1, energization of the electromagnetic coil 2 is ensured by two means.

One is a cold start switch SW5, which is the same as the conventional one. When this switch is turned on at the time of low temperature start, the electromagnetic coil 2 is energized to operate the electromagnetically driven valve 1 and close the exhaust pipe. .

The other is according to the present invention, and a normally closed control switch SW50 is connected in series with the clutch switch SW3 and the accelerator switch SW1.

When the coil 10 is energized, the control switch SW50 is turned off by magnetic power generated in accordance with the energization. Turns on when power is turned off. Thus, coil 10
Functions as a switch driving means for controlling ON / OFF of the control switch SW50.

One end of the control switch SW50 is grounded, and the other end is connected to the engine speed determination unit 11. This rotation speed judging unit 11 is provided with a starter switch SW4 and a fuse 1
2 and is supplied with power.

The rotation speed determination unit 11 is also connected to a rotation sensor 13 that detects the rotation speed of the engine, and receives an information signal related to the rotation speed of the engine.

The rotation speed judging unit 11 receives the information on the engine rotation speed from the rotation sensor 13, compares the information with a preset reference value, for example, 1000 rpm, and limits the coil 10 to only the reference value or less.
To turn off the control switch SW50, that is, to open it. These control switch SW50, coil 10, and rotation speed judging unit 11
It is a component of.

During operation, when the engine speed is higher than 1000 rpm, the control switch SW5
0 is ON, that is, a state of being closed is maintained. If it is less than 1000 rpm, the coil 10 is energized and the control switch SW50 is turned off, so that the exhaust brake does not work. Here, 1000 rpm corresponds to a predetermined rotation speed in an engine rotation speed region in which the deceleration of the engine by the closing movement of the electromagnetically driven valve is substantially possible. As a result, a situation in which the oil temperature increases due to the torque converter slip is avoided, and protection of the automatic transmission is achieved.

[Effect of the invention]

According to the present invention, if the engine speed decreases to a certain low-speed rotation region required as a control condition of the automatic transmission while the vehicle is running, the exhaust brake does not function and the automatic transmission is protected. . The protection of such an automatic transmission is that, even if the clutch fails for some reason and remains closed, if the engine speed drops below a predetermined speed, the control switch opens and the electromagnetically driven valve opens. Made by Further, in such a low-speed rotation region, the traveling speed is low, and the necessity of the exhaust brake is also small. Therefore, there is no actual harm caused by the ineffectiveness of the exhaust brake.

[Brief description of the drawings]

FIG. 1 is a diagram of an exhaust brake control circuit illustrating an embodiment of the present invention, and FIG. 2 is a circuit diagram according to the prior art. 10 ... Coil (as switch driving means), 11 ... Rotation speed judgment unit, 15 ... Controller, SW50 ... Control switch.

Claims (1)

(57) [Scope of request for utility model registration] An exhaust valve of an internal combustion engine of a vehicle equipped with an automatic transmission in which a driving force of the internal combustion engine is transmitted through a fluid coupling is provided with an electromagnetically driven valve for opening and closing the exhaust pipe. A valve drive circuit, an exhaust brake control circuit including at least a clutch switch that opens the drive circuit when the clutch pedal is operated and closes the drive circuit when the clutch pedal is not operated; a rotation sensor that detects a rotation speed of the internal combustion engine;
A control switch connected in series with the clutch switch and provided in the drive circuit; and an engine rotation speed detected by the rotation sensor during deceleration of the internal combustion engine due to the closing operation of the electromagnetic drive valve. An exhaust brake control circuit, comprising: a controller that closes the control switch when the engine speed is higher, and opens the control switch when it is determined that the engine speed has decreased to a predetermined speed or less.