Internal-combustion engines – Charge forming device – Fuel injection system
Patent
1981-12-03
1984-02-28
Cox, Ronald B.
Internal-combustion engines
Charge forming device
Fuel injection system
123478, 7386122, F02B 0000
Patent
active
044336632
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
This invention relates to electronically controlled fuel injection devices for the internal combustion engines used in automobiles, and in particular relates to electronically controlled fuel injection devices for internal combustion engines which are provided with a Karman vortex flow meter which detects the amount of intake air to the engine, and an electromagnetic valve for injecting fuel which injects fuel synchronously with a frequency output from the Karman vortex flow meter.
BACKGROUND ART
As is generally known, a Karman vortex flow meter produces a frequency output which corresponds to a vortex velocity (number of Karman vortices) which is proportional to the intake air flow to be detected. Methods of injection feeding a fixed quantity of fuel to an engine synchronously with a frequency output proportional to the intake airflow have been proposed in Japanese Utility Model Laid Open No. 133919/1978, and Japanese Patent Laid Open No. 5448/1979.
However, in such Karman vortex flow meters, the Karman vortex frequency f is related to the width d of the vortex generating body, and the airflow velocity v, by the equation f=St.sub.v/d. In this equation, St is a constant known as the Strouhal number. This Strouhal number, as shown in FIG. 1, varies in accordance with the Reynolds number, Re, which is proportional to the product of the abovementioned d and v. Accordingly, it is necessary to compensate for the variations in the Strouhal number when fuel is injection fed to engine synchronously with the abovementioned Karman vortex frequency f.
On the other hand, the fuel injection frequency is proportional to the intake airflow, so during idling of the engine, when the intake airflow is small, the injection frequency becomes extremely low, and the idling becomes unstable. Accordingly, for said idling state, consideration could be given to increasing the airflow velocity v, or; to reducing the width d of the vortex generating body, in order to increase the Karman vortex frequency f. However, increasing the airflow velocity v also increases pressure losses, and reducing the width d of the vortex generating body results in the size of the Karman vortices produced being made smaller, making it difficult to detect the Karman vortices, while pulsation of the intake air might disturb the generation of Karman vortices, making it impossible to detect then with accuracy.
DISCLOSURE OF THE INVENTION
This invention eliminates the aforementioned drawbacks of the prior art by making it possible to increase the fuel injection frequency during idling, obtaining for a stable idling, without increasing pressure losses, by providing a fuel injection device for an internal combustion engine which is provided with a Karman vortex flow meter which detects the intake airflow volume of the engine, and an electromagnetic fuel injection valve which injects fuel synchronously with a frequency output, corresponding to the vortex velocity, from the Karman vortex flow meter, the fuel injection device being constituted such that idling of the engine is conducted in the vicinity of a flow speed at which the Strouhal number is substantially a maximum, in the low flow velocity range of the Karman vortex flow meter.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a graph showing the relationship of the Strouhal number, St, to the Reynolds number, Re;
FIG. 2 is a cross-sectional diagram illustrating an embodiment of the present invention.
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 2 is a cross-sectional diagram illustrating a preferred embodiment of the present invention, wherein an intake port (not shown) of an engine (1) is connected in a gas-tight manner via an intake manifold pipe (2) to a mixture chamber (3), from which the passage of an air-fuel mixture is controlled by means of a throttle valve (3a) linked by a suitable linkage mechanism (not shown), to the automobile's accelerator pedal (not shown). Air passes into the mixture chamber (3) from the air cleaner (7) via a vortex flow meter (4) which comprises a
REFERENCES:
patent: 3680375 (1972-08-01), Jey et al.
patent: 3722275 (1973-03-01), Rodely et al.
patent: 3818877 (1974-06-01), Barrera et al.
patent: 3881352 (1975-05-01), McShane
patent: 3956928 (1976-05-01), Barrera
patent: 3965730 (1976-06-01), Innes
patent: 3967596 (1976-07-01), Comley
patent: 4263884 (1981-04-01), Suzuki
patent: 4336782 (1982-06-01), Endo
Cox Ronald B.
Mitsubishi Denki & Kabushiki Kaisha
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