JPS601362A - Low-speed control unit for engine - Google Patents

Abstract

PURPOSE:To make an accurate air-fuel mixture feedable with a simple structure, by connecting an auxiliary passage to the downstream side of a throttle valve in a suction passage, while separately controlling the air and fuel fed to an engine by way of this auxiliary passage according to the engine temperature. CONSTITUTION:An auxiliary passage 5 connecting the inlet of a suction passage 2 to the downstream side of a throttle valve 4 is formed, while a fuel feed inlet 6 consisting of a projected nozzle and a butterfly valve type auxiliary valve 7 are installed in this auxiliary passage 5. And, partial fuel is fed to the auxiliary passage 5 from a fuel passage 8 via the fuel feed inlet 6, and a control valve 9 is installed in position opposed to the fuel feed inlet 6. In addition, a temperature feeler mechanism 12 is coupled with an auxiliary shaft 10 via an auxiliary arm 11, and an air quantity is regulated after making the auxiliary valve 7 rotatable. On the other hand, each electric signal out of temperature sensors 19 and 20 for both engine and atmospheric temperatures and a temperature sensor 21 of a heater 17 is transmitted to a control unit 18 whereby a heating value of the temperature feeler mechanism 12 and a duty ratio of the control valve 9 are controlled so as to give the required air-fuel ratio.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a low-speed control device that enables an engine to be started, particularly, to be reliably started, and to be properly warmed up.

As is well known, the carburetor, which is one of the devices that supplies air-fuel mixture to the engine, is connected to the low-speed system that delivers fuel according to the negative pressure in the intake pipe. A choke device is installed to control the amount of intake air in order to supply the proper mixture.The choke device is a bimetallic link mechanism that connects the choke box and throttle valve outside the carburetor body.

Since a correction mechanism such as a cam is provided, the carburetor is extremely complicated and inevitably increases in size as a whole. Furthermore, conventional choke devices cannot accurately control the air-fuel ratio and do not supply a mixture that corresponds to the actual warm-up state of the engine. Therefore, an electronic control unit is used to control the air-fuel ratio. In many cases, measures are taken such as using a combination of equipment that performs this process, but this makes the equipment even more complicated.

The present invention solves these problems and provides a low-speed control device that can supply an appropriate air-fuel mixture with a simple configuration.
an auxiliary passage connected to the downstream side of the throttle valve in the intake passage and having a fuel inlet; an auxiliary valve that controls air passing through the auxiliary passage; and a control that controls fuel sent from the fuel inlet to the auxiliary passage. a temperature sensing mechanism with a heater that drives the auxiliary valve, and an electronic control unit, and the control unit controls the amount of heat generated by the heater and the opening/closing of the control valve according to the engine temperature. It is characterized by being configured to control the operation and adjust the amount of air and fuel in the auxiliary passage.

Next, a specific example of the present invention will be described with reference to 7 in the drawings.

The drawing shows an example of a carburetor according to the present invention, in which an intake passage 2 extending in the vertical direction of a body 1 has a venturi 3 and a throttle valve 4. An auxiliary passage v35 is formed parallel to the intake passage 2 to connect the intake passage 2 to the downstream side of the intake passage 2.

A fuel inlet 6 consisting of a nozzle protruding into this auxiliary passage 5
and a butterfly-shaped auxiliary valve 7 that changes the effective area of the auxiliary passage 5 from zero to a maximum.

A part of the fuel sent out from the float chamber (not shown) is mixed with bleed air if necessary and sent through the fuel oil W18 to the auxiliary passage 5 from the fuel inlet 6. is installed opposite the fuel inlet 06-. This control valve 9 repeats opening and closing operations at fixed short intervals using a drive current consisting of pulses, and the fuel amount is adjusted by the duty ratio.

An auxiliary arm 11 is fixed to an auxiliary valve shaft 10 to which an auxiliary valve 7 is fixed, and the auxiliary valve is rotated by a temperature sensing mechanism 12 to adjust the amount of air. The temperature-sensing mechanism 12 includes an operating rod 14 that reciprocates linearly in response to expansion and contraction of the fluid material 1111 in response to temperature changes from a container 13 filled with an incompressible fluid material having a large coefficient of thermal expansion, such as thermowax. As the temperature rises, the operating rod 14 pushes the auxiliary arm 11 to rotate the auxiliary valve 1 in the direction of decreasing opening, and as the temperature decreases, the auxiliary valve 14 pushes the auxiliary arm 11 and rotates the auxiliary valve 1 by the action of a return spring (not shown). 14, it rotates in the direction of increasing the opening degree. The container 13 is inserted into a case 16 of a heater 17 which includes a case 16 containing a heating element 15 that generates misresistance heat, and the fluid substance is heated by the heat generated by the two heating elements 15.

Electrical signals are sent to the electronic control unit 8 from temperature sensors 19 and 20 that detect the engine temperature and atmospheric temperature, and a temperature sensor 21 that detects the temperature of the heater 17. The temperature sensing mechanism drives the auxiliary valve 7 to provide the air-fuel ratio required at startup depending on the engine temperature and atmospheric temperature.
control the duty ratio of In addition, after starting, the warm-up condition is detected based on the engine temperature, necessary correction is made based on the atmospheric temperature, and the temperature sensing mechanism 12 and the control valve 9 are controlled diagonally. 21 monitors whether the heater 17 is controlled to a required amount of heat and corrects the current supplied to the heating element 15. When warming up is completed, the auxiliary valve 7 is fully closed, but when the engine load fluctuates during idling, it is opened to maintain engine rotation.

The electrical signals output by these three temperature sensors 19, 20, and 21 are processed by the controller 18, and appropriate heating current and drive current are sent to the heater 17° control valve 9. Opening degree of throttle valve 4.

Suction pipe negative pressure, intake air amount, engine speed.

It detects the operation of equipment that generates electrical loads, the oxygen concentration in engine exhaust gas, the operation of the exhaust gas recirculation device, etc., and sends this information to the control unit 18, which controls the air-twisting ratio during low-speed operation and other operations. In some cases, this may be done in a more detailed manner. Temperature sensor 19 that detects engine temperature
is installed to detect the temperature of engine cooling water or lubricating oil, and a temperature sensor 20 for detecting atmospheric temperature is installed in the intake path 2. Installed in place inside the suction pipe or outside the vaporizer.

2. The present invention is applicable not only to the carburetor type but also to the fuel injection type mixture supply device.

In this case, the fuel inlet 6 and the control valve 9 are constituted by a fuel injection valve. Furthermore, instead of adjusting the amount of fuel by the duty ratio of the opening/closing operation, the control valve 9 may change the opening degree of the fuel inlet 6 steplessly. Additionally, all of the low velocity fuel can be provided in the inventive auxiliary passageway without the need for conventional low velocity acid.

As described above, the invention connects an auxiliary passage to the downstream side of the throttle valve in the intake passage, and separately controls the air and fuel supplied to the engine through this auxiliary passage by a control unit according to the engine temperature. This not only makes it possible to supply the optimum air-fuel mixture according to the temperature at startup to ensure a reliable start, but also controls the amount of heat generated by the heater during warm-up and adjusts the amount of air, so the fuel is at the same time By adjusting the amount, a mixture with an air-fuel ratio of 9 and 9 corresponding to the actual warm-up state of the engine is appropriately supplied, and stable warm-up operation is performed. Further, the structure is simpler than the conventional complicated and large choke device and its auxiliary air-fuel ratio control device.

[Brief explanation of drawings]

The drawing is a vertical Iyr plane view showing a specific example of the present invention. 2... Intake path, 4... Throttle valve, 5... Old auxiliary passage, 6... Fuel inlet, 7...
...Auxiliary valve, 9...Control valve, 12...
Temperature-sensing mechanism,] 7. Old... Heater. 18...control unit), 19,20.21
・・Eyes・・Temperature sensor.

Claims (1)

[Claims] an auxiliary passage connected to the downstream side of the throttle valve of the intake passage and having a fuel supply O; an auxiliary valve that controls air passing through the auxiliary passage; and an auxiliary valve that controls fuel supplied from the fuel supply port to the auxiliary passage. It includes a control valve, a temperature sensing mechanism with a heater that drives the auxiliary valve, and an electronic control unit, and the control unit controls the amount of heat generated by the heater and the opening/closing operation of the control valve according to the engine temperature. 1. A low-speed control device for an engine, characterized in that it is configured to control 16 and adjust the amount of air in the auxiliary passage and the amount of fuel t.