Altitude compensating device of an internal combustion engine
AssigneeToyota Jidosha Kogyo Kabushiki Kaisha
InventorKazuo Shinoda
Life of this patent
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Abstract
An internal combustion engine comprising a secondary air feed control device for feeding secondary air into the exhaust passage from the air pump. The amount of the secondary air fed into the exhaust passage is controlled by the output signal of an oxygen concentration detector arranged in the exhaust passage. An air-fuel ratio control device is arranged in the main fuel passage of the carburetor for controlling the amount of air bled into the main fuel passage in response to the output signal of the oxygen concentration detector. The amount of the air bled into the main fuel passage is increased as the altitude becomes higher so as to reduce the difference between the stoichiometric air-fuel ratio and an air-fuel ratio of the mixture formed by the carburetor.
Claims10
An altitude compensating device of an internal combustion engine comprising an intake passage, a fuel feed apparatus arranged in said intake passage, an exhaust passage, and an air pump driven by said engine and connected to said exhaust passage via a secondary air feed passage, said device comprising:
- a detector arranged in said exhaust passage for detecting the overall air-fuel ratio to produce a detecting signal;
- a first comparator for comparing said detecting signal with a first reference voltage to produce an output signal, the potential of which is a high level when the total air-fuel ratio is less than the stoichiometric air-fuel ratio, but is a low level when the total air-fuel ratio is greater than the stoichiometric air-fuel ratio;
- a first integrator for integrating the output signal of said first comparator;
- an adder for adding an output signal of said first integrator to the output signal of said first comparator;
- first means for generating a first train of pulses, each having a width which is proportional to the level of the output signal of said adder;
- secondary air feed control means arranged in said secondary air feed passage and actuated in response to said first train of pulses for increasing the amount of the secondary air fed into said exhaust passage from said air pump in accordance with an increase in the width of the pulse of said first train of pulses;
- a second integrator for integrating the output signal of said adder to produce an output signal having a level which corresponds to the mean value of the output signal of said adder and is increased in accordance with an increase in altitude, the time constant of said second integrator being greater than that of said first integrator;
- second means for generating a second train of pulses, each having a width which is proportional to the level of the output signal of said second integrator, and;
- air-fuel ratio control means arranged in said fuel feed apparatus and actuated in response to said second train of pulses for increasing the air-fuel ratio of a mixture formed by said fuel feed apparatus to reduce the difference between the air-fuel ratio of said mixture and the stoichiometric air-fuel ratio when the altitude is higher than a predetermined level.
Dependencies are inferred from the claim text.