Programmed control system for a lean-burning internal combustion engine
AssigneeYamaha Hatsudoki Kabushiki Kaisha
InventorsRyuichi Yamashita, Hiromitsu Matsumoto, Masato Eda
Life of this patent
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Abstract
A system and method for controlling a lean-burning internal combustion engine. The system and method enable a starter carburetor to operate at cold but not at hot temperature, to provide gulp air and counterbalance means for the starter carburetor, together with means to inhibit them at startup and for a brief time thereafter, and to inhibit exhaust gas recirculation when it would be deleterious to smooth operation. The system also provides for continuous accelerator pump operation during acceleration except at high temperatures. The objective is to secure smooth operation at startup, cold, warm or hot, and during transient conditions during engine warmup.
Claims22
In a carburetion system for an internal combustion engine which includes a principal carburetor, a starter carburetor, and an air gulp valve, which carburetors discharge a mixture of air and fuel into induction means, the induction means including a throttle valve whereby an induction pressure is established at a downstream location from the throttle valve that is respective to engine operating conditions, the starter carburetor including a fuel chamber containing fuel overlaid by a region having limited communication with the atmosphere, balance passage means interconnecting the said downstream location to the region, the gulp valve comprising gulp valve means operable to atmosphere, and gulp passage means connecting the said gulp valve means to the said downstream location, the improvement comprising:
- balance passage valve means in said balance passage means effective to permit or to prevent air flow through said balance passage means;
- balance passage valve actuator means operably connected to said balance passage valve means adapted to set the said balance passage valve means to permit or to prevent said air flow;
- gulp valve actuator means operably connected to said gulp valve to prevent or to enable flow of air from atmosphere through the gulp valve to said gulp passage means;
- and
- delay means operatively connected to both of said actuator means causing both of said actuator means to prevent said flows until after a predetermined period of time has elapsed following catching of the engine after cranking.
In a carburetion system for an internal combustion engine which inclues a principal carburetor, a starter carburetor, and an air gulp valve, which carburetors discharge a mixture of air and fuel into induction means, the induction means including a throttle valve whereby an induction pressure is established at a downstream location from the throttle valve that is respective to engine operating conditions, the starter carburetor including a fuel chamber containing fuel overlaid by a region having restricted communication with the atmosphere, balance passage means interconnecting the downstream location to the region, the gulp valve comprising gulp valve means operable to atmosphere, and gulp passage means connecting the said gulp valve means to the downstream location, disabling means to prevent the flow of fluid from the starter carburetor to the induction means, an exhaust gas recirculation conduit, an exhaust gas recirculation valve disposed in said recirculation conduit, and recirculation valve actuator means so disposed and arranged as selectively to prevent or to enable recirculation, the improvement comprising:
- relay means for controlling the aforesaid in respective temperature ranges during running operation as follows:
- in a first range of low temperature, preventing recirculation, enabling the starter carburetor, and, after a delay from the start of running, enabling gulp air flow and flow through the balance passage means;
- in a second range of higher temperatures than the first range, permitting recirculation and preventing the starter carburetor, both after no more than a specified maximum delay, and enabling gulp air flow;
- in a third range of higher temperatures than the second range, permitting recirculation and preventing the starter carburetor, and enabling gulp air flow;
- and
- in a fourth range of higher temperatures than the third range, permitting recirculation and preventing the starter carburetor, and causing gulp air flow to be enabled at a different rate than formerly.
In a carburetion system for an internal combustion engine which includes a principal carburetor and a starter carburetor, which carburetors discharge a mixture of air and fuel into induction means, the induction means including a throttle valve whereby an induction pressure is established at a downstream location from the throttle valve that is respective to engine operating conditions, the starter carburetor including a fuel chamber containing fuel overlaid by a region having restricted communication with the atmoshphere, balance passage means interconnecting the said downstream location to the region, the improvement comprising:
- balance passage valve means in said balance passage means effective to permit or to prevent air flow through said balance passage means;
- balance passage valve actuator means operably connected to said balance passage valve means adapted to set the said balance passage passage valve means to permit or to prevent said air flow;
- and
- delay means operatively connected to the said actuator means causing said actuator means to prevent said flow until after a predetermined period of time has elapsed following catching of the engine after cranking.
In a carburetion system for an internal combustion engine which includes a principal carburetor and an air gulp valve, which carburetor discharges a mixture of air and fuel into induction means, the induction means including a throttle valve whereby an induction pressure is established at a downstream location from the throttle valve that is respective to engine operating conditions, the gulp valve comprising gulp valve means openable to atmosphere, and gulp passage means connecting the said gulp valve means to the said downstream location, the improvement comprising:
- gulp valve actuator means operably connected to said gulp valve to prevent or to enable flow of air from atmosphere through the gulp valve to said gulp passage means;
- and
- delay means operatively connected to the said actuator means causing said actuator means to prevent said flow until after a predetermined period of time has elapsed following catching of the engine after cranking.
Dependencies are inferred from the claim text.