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AssigneeYamaha Hatsudoki Kabushiki Kaisha
InventorsNoriyuki Kurihara, Yoshikatsu Iida, Hiromatsu Matsumoto
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Several embodiments of engines and systems for fueling engines to reduce the emission of unwanted exhaust gas constituents and to improve the fuel economy of the engine. A catalytic converter is provided in the exhaust system and a gaseous fuel is used at least during starting so as to bring the catalytic converter up to its operating temperature rapidly without necessitating the provision of an enriched fuel/air mixture. An oxygen sensor is employed in the exhaust system and a feedback control system varies the fuel/air ratio of the engine during its running in response to the output of the oxygen sensor. In order to test that the oxygen sensor is at its operating condition before feedback control is initiated, a rich fuel mixture is supplied and this rich fuel mixture is discontinued immediately upon the receipt of a signal from the oxygen sensor indicating that a rich mixture exits. Applications of the principal to both air valve type of carburetors and conventional carburetors are disclosed.
A charge forming and induction system for an internal combustion engine having a combustion chamber, an induction system for supplying a charge to said combustion chamber, said induction system comprising a charge forming device having an induction passage communicating at one end with atmospheric air and at another end with said combustion chamber, a throttle valve in said induction passage, means for automatically controlling the position of said throttle valve to maintain a substantially constant pressure in the induction passage in the area of the throttle valve during the running of said engine, a main fuel discharge circuit discharging into said induction passage contiguous to said throttle valve and including a fuel control valve for controlling the amount of fuel supplied from said main fuel discharge circuit, means for controlling the condition of said fuel control valve in response to the position of said throttle valve, an idle discharge circuit for supplying fuel to said engine downstream of said main fuel discharge circuit, a source of gaseous fuel under pressure as a liquid, means for supplying fuel from said source to said fuel discharge circuits, an exhaust system for said engine, a sensor in said exhaust system for sensing a characteristic of the exhaust gases from said engine, and means for selectively adding air to the fuel supplied to at least one of said fuel discharge circuits in response to the signal from said sensor for controlling the fuel/air ratio.
An emission control system for an internal combustion engine having a combustion chamber, an exhaust system for discharging exhaust gases from said combustion chamber to the atmosphere, an oxygen sensor in said exhaust system for sensing a rich fuel/air condition in the exhaust gases of said engine, an induction system including charge forming means for supplying a fuel/air mixture into said combustion chamber for combustion therein, means for controlling said charge former from the signal of said oxygen sensor for maintaining a desired fuel/air ratio for exhaust emission control, means for providing a rich fuel/air mixture to said combustion chamber during initial engine operation for testing when said oxygen sensor is operative to supply a signal indicative of a rich fuel condition, and means for thereafter controlling the supply of fuel/air mixture by said oxygen sensor.
An emission control system for an internal combustion engine having a combustion chamber, an exhaust system for discharging exhaust gases from said combustion chamber to the atmosphere, a catalyzer in said exhaust system for treating the exhaust gases issuing from said combustion chamber, an induction system for supplying a charge to said combustion chamber, a charge former for supplying fuel to said induction system, a source of gaseous fuel stored under pressure as a liquid, and means for supplying fuel from said source to said engine in response to at least starting of said engine for rapidly heating said catalyzer to its operating temperature.
A method of operating an internal combustion engine having a combustion chamber, an exhaust system for discharging combustion products from said combustion chamber, a sensor in said exhaust system for sensing a condition of the exhaust gases, an induction system for supplying a charge to said combustion chamber, said induction system comprising a charge forming device having an induction passage communicating at one end with atmospheric air and at another end with said combustion chamber, a throttle valve in said induction passage, means for automatically controlling the position of said throttle valve to maintain a substantially constant pressure in the induction passage in the area of the throttle valve during the running of said engine, a main fuel discharge circuit discharging into said induction passage and including a fuel control valve for controlling the amount of fuel supplied from said main fuel discharge circuit, means for controlling the condition of said fuel control valve in response to the position of said throttle valve, an idle discharge circuit for supplying fuel to the engine downstream of said main fuel discharge circuit and a source of gaseous fuel under pressure as a liquid, said method comprising the step of supplying fuel from said source to said fuel discharge circuits and adjusting the air/fuel ratio in response to the output of the sensor.
An emission control system for an internal combustion engine having a combustion chamber, an exhaust system for discharging exhaust gases from said combustion chamber to the atmosphere, an oxygen sensor in said exhaust system for sensing a rich fuel condition in the exhaust gases of said engine, an induction system including charge forming means for supplying a fuel/air mixture into said combustion chamber for combustion therein, means for controlling said charge former from the signal of said oxygen sensor for maintaining a desired fuel/air ratio for exhaust emission control, said system comprising providing a rich fuel/air mixture to said combustion chamber during initial engine operation for testing when said oxygen sensor is operative to supply a signal indicative of a rich fuel condition, and thereafter controlling the supply of fuel/air mixture by said oxygen sensor.
An emission control system for an internal combustion engine having a combustion chamber, an exhaust system for discharging exhaust gases from said combustion chamber to the atmosphere, a catalyzer in said exhaust system for treating the exhaust gases issuing from said combustion chamber, an induction system for supplying a charge to said combustion chamber, a charge former for supplying fuel to said induction system, said system comprising a source of gaseous fuel stored under pressure as is a liquid, and supplying fuel from said source to said engine in response to at least starting of said engine for rapidly heating said catalyzer to its operating temperature.
Dependencies are inferred from the claim text.