JPS6124538B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is provided with a mixture passage for starting, a means for adjusting the flow rate and air-fuel ratio of the mixture so as to control the engine speed in accordance with the engine temperature; This invention relates to a carburetor equipped with means for performing altitude correction.

Among the carburetors, many of those used in internal combustion engines of automobiles are equipped with an automatic choke mechanism as a mechanism for supplying a highly concentrated air-fuel mixture to facilitate engine starting in cold weather. It is well known that when starting with a carburetor equipped with this automatic throttle mechanism, the engine speed increases as the engine warms up. It is necessary to operate the fast idle cam that is linked to the throttle valve to reduce the opening of the throttle valve, and if left as is, the engine rotation speed will increase unnecessarily and the mixture will continue to have a higher concentration than necessary. This increases harmful components in the supplied exhaust gas and causes problems such as significant engine noise.

The present invention maintains the engine rotation speed at the optimum value necessary for warm-up operation by providing a starting mixture passage having a means to operate according to the rotation speed and temperature of the engine instead of the engine rotation speed. Moreover, after warming up, idling operation is automatically carried out, thus completely eliminating the above-mentioned drawbacks.

That is, the carburetor according to the present invention includes: a starting mixture passage connected to the downstream side of the throttle valve; a valve that steplessly adjusts the effective area of the mixture passage; and a driving section for the valve. It is equipped with a fuel control device consisting of a fuel metering valve for supplying fuel to the mixture passage and its driving part, and an electronic control unit that stores an appropriate rotational speed and an appropriate mixture ratio corresponding to the engine temperature. The valve is controlled by an output signal sent from the control unit so that the temperature and rotational speed are detected and compared with the proper rotational speed and the proper mixture ratio, and a mixture of a predetermined mixing ratio that provides a predetermined rotational speed is supplied. A drive unit is operated to adjust the flow rate of the air-fuel mixture, a drive unit for the metering valve is operated to control the fuel, and the valve and the metering valve are fully closed at the end of warm-up; A feature of this configuration is that an altitude correction device is provided and air is supplied using the air-fuel mixture passage.

Embodiments of the present invention will be described below with reference to the drawings. 1 is a carburetor main body, 2 is a bench lily, 3 is a throttle valve, 4 is a constant oil level chamber, 5 is a main jet, 6 is a main nozzle, and 7 is a main fuel. passage, 8 indicates a low speed fuel passage;
A suitable place upstream of the bench lily 2, for example, the air inlet _1a of the carburetor body 1 (or sometimes inside the air cleaner), and a suitable place downstream of the throttle valve 3, such as the air-fuel mixture outlet _1b (or the intake manifold) A jet 11 is connected to the starting air-fuel mixture passage 9 with a bench lily 10 formed near the entrance of the air-fuel mixture passage 9 and opened near the bottom of the constant oil level chamber 4.
A fuel passage 12 having a diameter is connected to a nozzle 13 opened in the bench lily 10, and a valve 14 is provided near the outlet of the mixture passage 9. The valve 14 includes a valve seat 15 formed in the air-fuel mixture passage 9 and a valve body 16 having a needle-shaped or conical tip. The driving part 17 of the valve 14 is a stator 18 fixedly attached to the vaporizer main body 1.
and a rotor 19 that can be rotated in forward and reverse directions.
0 to the carburetor main body 1. The control unit 21 of the drive section 17 is a computer, typically a dedicated microcomputer consisting of a large-scale integrated circuit, or an existing computer installed in the vehicle, and detects the engine rotational speed and the engine temperature, such as cooling water and lubrication. The input signal from the oil temperature detection unit 23 is compared with pre-given data, and a required output signal is sent to the stator 18 to rotate the rotor 19 and operate the valve while rotating the valve body 16 with the threaded rod 20. By moving it relative to the seat 15, the effective area of the valve seat opening _15a is steplessly adjusted between fully closed and fully closed.

If the engine temperature is low when starting the engine, it is necessary to increase the appropriate rotation speed for warm-up operation, and as the engine temperature increases, the appropriate rotation speed decreases, so the appropriate rotation speed for warm-up operation must be increased. can be considered to be a function of engine temperature. Therefore, the control unit 2 stores the appropriate rotational speed corresponding to the engine temperature in advance.
1, the drive unit 17 is operated to adjust the opening degree of the mixture passage 9 by the valve 14 so that the rotation speed is appropriate according to the engine temperature detected by the temperature detection unit 23, and the engine suction negative pressure is adjusted. Yotsute bench lily 2
When the air sucked into the mixture passage 9 from the upstream side of the throttle valve 3 passes through the vent lily 10, fuel is sucked out from the nozzle 13, and the air is turned into a mixture and supplied to the downstream side of the throttle valve 3. In this case, if the actual rotational speed of the engine detected by the rotational speed detection section 22 is different from the appropriate rotational speed stored in the control unit 21, the drive section is configured to correct the actual rotational speed to the appropriate rotational speed. 17 is activated. For example, when the rotational speed decreases due to engine malfunction during warm-up, the opening degree of the valve 14 is increased to restore the proper rotational speed and continue stable operation without stopping the engine.

When the engine temperature reaches a specified temperature, the valve 14 is in the fully closed position and the supply of starting air-fuel mixture is stopped, and from then on, idling operation corresponding to the opening degree of the throttle valve 3 is performed.

Here, when the engine temperature is low, the vaporization of the fuel is poor and the proportion of fuel that is effectively combusted is small, so it is necessary to replenish that extra fuel, and the required mixture ratio during warm-up is the same as the rotation speed. It can be thought of as a function of engine temperature. Therefore, in this embodiment, the fuel passage 12 is fully opened at the time of cold start and the necessary high concentration air-fuel mixture is sent to the engine, but as the temperature rises, the fuel passage 12
A fuel control device 33 is provided which gradually reduces the effective area of the engine and completely closes the engine at the end of warm-up operation. This device 33
It consists of a metering valve 35 with a needle-shaped tip inserted into the jet 11 at the entrance of the fuel passage 12 and its driving part 36, and a stator 37 and a rotor 38 rotating therein.
A screw rod 39 and a metering valve 35 are sequentially and integrally attached to a rotor 38 of a drive section 36 consisting of a servo motor, and the screw rod 39 is screwed into the bottom of the float chamber 4. The relationship between the effective area of the jet 11 by the metering valve 35, that is, the amount of fuel passing through, and the engine temperature is set in advance and stored in the control unit 21 so that an appropriate mixture ratio can be obtained in accordance with the engine temperature. An output signal corresponding to the engine temperature detected by the section 23 is sent from the control unit 21 to the drive section 36 to thin the air-fuel mixture as warm-up progresses, and after the warm-up operation is completed, the fuel passage 12 is closed and the air-fuel mixture is passed to the air-fuel mixture passage 9. Prevent fuel from being sucked out.

Further, an altitude correction device 34 is provided to eliminate the phenomenon that the air mixture becomes richer due to lower air density at high altitudes. This device 34 replenishes air in an amount depending on the altitude by using the mixture passage 9 with the fuel passage 12 closed after the warm-up operation is completed. A valve 41 opens and closes an air port 40 that opens at a suitable location between the throttle valve 3 of the carburetor body 1 and the bench lily 2.
and a drive section 42 thereof. The drive unit 42 is composed of a servo motor consisting of a stator 43 and a rotor 44 rotating therein.
A valve body 46 having a needle-shaped or conical tip facing a valve seat 45 formed in the air port 40 is integrally attached to the rotor 44 via a threaded rod 47 threaded onto the carburetor body 1. When the air-fuel mixture passage 9 is open downstream of the throttle valve to perform warm-up operation, the valve 41 is opened at the air port 4.
0 is closed. Pressure detection unit 48 consisting of a bellows that expands and contracts in response to changes in atmospheric pressure after the warm-up operation is completed.
An output signal corresponding to the atmospheric pressure detected by the controller is sent from the control unit 21 to the drive section 42, and insufficient air is replenished from the mixture passage 9 through the air port 40 in accordance with the air density. In other words, the relationship between the air density and the altitude and the amount of make-up air, that is, the opening degree of the valve 41, is stored in the control unit 21 in advance.

It goes without saying that instead of the servo motors, various types of motors, such as step motors, can be used for each of the drive units 17, 36, 42 to steplessly adjust the opening degree of the valves.

As described above, when the engine needs to be warmed up after starting, the present invention provides an air-fuel mixture passage that opens downstream of the throttle valve at an opening degree that corresponds to the engine temperature, instead of the conventional choke mechanism. Because of this, as the engine warms up, the engine speed increases and the air-fuel mixture becomes more concentrated than necessary, increasing harmful components in the exhaust gas and producing significant engine noise. This inconvenience is completely eliminated, and there is no need to depress the accelerator pedal to reduce the engine speed during warm-up.

That is, according to the present invention, it is possible not only to detect the engine temperature and steplessly control the amount of air-fuel mixture supplied so as to provide the optimum rotation speed for warm-up operation at that temperature, but also to detect the engine rotation speed and adjust the rotation speed to the appropriate level. This allows for stable warm-up operation without having to worry about stopping the engine to adjust the speed. In addition, the rich mixture required at low temperature starting can be supplied without shortage by widening the opening of the fuel passage to the mixture passage, and the engine is adjusted to the set value stored in advance in the control unit circuit. Temperature and rotational speed are given as input signals and compared, each drive section is operated and the engine rotational speed is automatically maintained at the optimal value required for warm-up operation, and after warming up, it is adjusted according to the opening of the throttle valve. The idling operation continues.

Furthermore, according to the present invention, since the fuel control device controls the fuel to the mixture passage so that it has an appropriate mixture ratio corresponding to the engine temperature, it not only supplies a highly concentrated mixture at low temperatures, but also improves the temperature during warm-up. The flow rate of the mixture through the mixture passage and its air-fuel ratio level are properly controlled by different means so that the mixture becomes thinner as the mixture progresses, and optimal heating is achieved without causing incomplete combustion due to over-richness of the mixture. It is possible to operate the machine.

Furthermore, since the air-fuel mixture passage is equipped with an altitude correction device that replenishes air according to the altitude after warming up, it is possible to compensate for the lack of air amount at high altitudes with an extremely simple configuration.

[Brief explanation of the drawing]

The drawings are longitudinal sectional views showing embodiments of the present invention. DESCRIPTION OF SYMBOLS 1... Carburetor body, 3... Throttle valve, 9... Mixture passage, 10... Bench lily, 11... Jet, 12... Fuel passage, 14... Valve, 17... Drive unit, 21... Control unit, 22... Engine rotation speed detection section, 23... Engine temperature detection section, 33...
Fuel control device, 34... Altitude correction device, 35...
Metering valve, 36... Drive unit, 40... Air port, 41
... Valve, 42 ... Drive section, 48 ... Pressure detection section.

Claims (1)

[Scope of Claims] 1. A starting mixture passage 9 connected to the downstream side of the throttle valve 3, a valve 14 for steplessly adjusting the effective area of the mixture passage 9, and a driving section for the valve 14. 17
and a metering valve 3 for supplying fuel to the mixture passage 9.
5 and its drive unit 36.
3, and an electronic control unit 21 that stores the appropriate rotational speed and mixture ratio corresponding to the engine temperature.
The control unit 21 detects the temperature and rotational speed of the engine, compares it with the proper rotational speed and the proper mixture ratio, and supplies the air-fuel mixture at a predetermined mixing ratio that provides a predetermined rotational speed. The drive unit 17 of the valve 14 is operated by the output signal to adjust the flow rate of the air-fuel mixture, and the drive unit 36 of the metering valve 35 is operated to control the fuel. 3. A carburetor characterized by being configured such that 35 is completely closed. 2. A starting mixture passage 9 connected to the downstream side of the throttle valve 3, a valve 14 that steplessly adjusts the effective area of this mixture passage 9, and a drive unit 17 for the valve 14.
and a metering valve 3 for supplying fuel to the mixture passage 9.
5 and its drive unit 36.
3, an altitude correction device 34 consisting of a valve 41 and its driving part 42, and an electronic control unit 21 that stores the appropriate rotational speed and mixture ratio corresponding to the engine temperature, and controls the engine temperature and rotational speed. The mixture passage 9 is controlled by an output signal sent from the control unit 21 so that a mixture having a predetermined mixture ratio that provides a predetermined rotation speed is supplied by detecting the rotation speed and the proper mixture ratio. The drive section 17 of the valve 9 that adjusts the effective area is operated to adjust the flow rate of the air-fuel mixture, and the drive section 36 of the metering valve 35 is operated to control the fuel. 36 is fully closed, and further, the control unit 21 is configured to completely close the air-fuel mixture 36 and replenish air in an amount corresponding to the altitude through the air-fuel mixture passage 9 after the warm-up is completed.
The altitude correction device 3
A carburetor characterized in that it is configured to operate a drive section 42 of No. 4.