Method and apparatus to remove polluting components from the exhaust gases of internal combustion engines

Claim 2

Method to remove polluting components from the exhaust gases of internal combustion engines comprising applying an air-fuel mixture to the inlet manifold (12'') of the engine (11) over a first path (13); controlling (14) the relative proportion of air and fuel in the air-fuel mixture being admitted through said first path, in accordance with a commanded input (30); measuring the oxygen content (23) of the exhaust gases from the engine; applying air to the inlet manifold (12'') of the engine (11) over a second path (17); and controling (18) the amount of air being admitted through the second path in accordance with a. the amount of air being admitted through the first path and, additionally, b. the measured oxygen content of the exhaust gases.

Claim 3

Method according to claim 1 wherein the step of controlling the amount of air being admitted through the first path (13) comprises setting a throttle valve (14) in the main air duct in accordance with a commanded position; and the step of controlling the amount of air being admitted through the second path (17) comprises providing an auxiliary air inlet duct (17), in shunt with the main air duct (14) and having an auxiliry valve (18); and controlling the position of the auxiliary valve (18) in accordance with the position of the main throttle valve (14) as modified by the measured oxygen content of the exhaust gases.

Claim 4

Method according to claim 1, wherein the step of controlling the amount of air being admitted through the second path comprises additionally controlling the Amount of air being admitted as a function of engine speed.

Claim 5

Method according to claim 1, wherein a control amplifier (25) is provided, and electrically controlled air flow means are provided in said second path, the output of the control amplifier controlling the air flow control means in the second path to effect the step of controlling the amount of air flowing through the second path; and wherein the range of output of the control amplifier (25) is controlled by at least one of the parameters: engine speed; air flow in the first path.

Claim 6

Method according to claim 4, wherein the control amplifier (25) has a variable delay time; and the delay between control input to the control amplifier and the control output thereof is varied in accordance with at least one of the parameters: engine speed; air flow in the first path.

Claim 7

Method according to claim 1, wherein the air flow in the second path (17) is controlled such that the relationship of air mass to fuel being supplied at the inlet manifold (12'') to the engine is just below the stoichiometric ratio and has a value of about 0.98.

Claim 8

Method according to claim 5, comprising the step of after-burning unburned carbon monoxide and hydrocarbons in a thermo reactor (19, 20), and then reducing nitrogen-oxygen compounds in a catalytic reactor (21) following the thermo reactor.

Claim 9

Internal combustion engine exhaust emission cleaning system, in which the internal combustion engine (11) has an inlet manifold (12''), means (15) introducing fuel into the inlet manifold; means (14) controlling the flow of air in the inlet manifold in a first path; means (17) introducing additional air into the inlet manifold in a second path; means (18) controlling the flow of additional air into the inlet manifold through an additional air path; exhaust gas analysis means (23) measuring the oxygen content of the exhaust gases and deriving an electrical sensing signal; and electromechanical control means connected to and controlling the flow control means for the additional air, the electromechanical control means having an input which is responsive to the amount of air flowing in the first path and further to said electrical sensing signal to control the flow of additional air as a function of the flow of air in the first path as well as a function of a predetermined relationship of oxygen in the exhaust gas as sensed by said exhaust gas analysis means (23).

Claim 10

Internal combustion engine exhaust emission cleaning system, in which the internal combustion engine (11) has an inlet manifold (12''), means (15) introducing fuel into the inlet manifold; means (14) controlling the flow of air in the inlet manifold in a first path; means (17) introducing additional air into the inlet manifold in a second path; means (18) controlling the flow of additional air into the inlet manifold through an additional air path; exhaust gas analysis means (23) measuring the oxygen content of the exhaust gases and deriving an electrical sensing signal; and electromechanical control means connected to and controlling the flow control means for the additional air, the electromechanical control means having an input which is responsive to the amount of air flowing in the first path and further to said electrical sensing signal to control the flow of additional air as a function of the flow of air in the first path as well as a function of a predetermined relationship of oxygen in the exhaust gas as sensed by said exhaust gas analysis means (23).

Claim 11

System according to claim 8, wherein the internal combustion engine has a settable control (30) including means (31) deriving a signal representative of the position of said control and applying said signal to the electromechanical control means in a direction to increase response time of said control means when the settable control is set for high power operation of the engine providing for high air flow through said first path.

Claim 12

System according to claim 8, wherein the means controlling the flow of air in the first path comprises a main throttle valve (14) having a shaft (34); the flow control means for the additional air path comprise an additional throttle valve (18) having an additional shaft (29); and the electro-mechanical control means comprises mechanical means (38, 100) responsive to throttle shaft (34) deflection connected to operate the additional throttle shaft (29) and additional electrical input position-output electrical signal transducer means (35) responsive to the electrical sensing signal additionally deflecting the additional throttle valve (18).

Claim 13

System according to claim 10, wherein the mechanical means comprises a bi-directional one-way clutch (38) connected at the driven side with the main throttle shaft (34) and at the driving side to the additional throttle shaft (29) to transmit rotary movement from the throttle shaft, in both rotary directions, to the additional throttle shaft (29) but not to transmit rotary movement in either rotational direction from the additional thrOttle shaft (29) to the main throttle shaft (34); and the electrical input-position output transducer comprises a synchro motor (35) and a slip coupling (37) connecting the synchro motor to the additional throttle shaft (29) to permit setting of the additional throttle (18) upon change in position of the main throttle shaft (34) and modifying this position under control of the operation of the synchro motor.

Claim 14

System according to claim 11, further comprising a closed servo loop (35, 36-39) including a position transducer (36) coupled to the output shaft of the synchro motor (35).

Claim 15

System according to claim 12, wherein the servo loop includes a servo amplifier (39) controlling the amount and direction of rotation of the synchro motor (35); and means including a reference source (40) connected to the position transducer, the output from the position transducer forming a comparison input to the servo amplifier (39).

Claim 16

System according to claim 13, wherein the electro-mechanical control means comprises a control amplifier (25) having an output connected to and controlling the servo amplifier (39); a source of command signals representative of commanded fuel-air ratio, said control amplifier having one input connected to said command source and another input connected to the output of the gas analysis means.

Claim 17

System according to claim 12, further comprising a position transducer (31) coupled to the main throttle shaft (34) to provide a signal representative of main throttle shaft deflection.

Claim 18

System according to claim 14, further comprising a position transducer (31) coupled to the main control shaft (34) to provide a signal representatve of main throttle shaft deflection; said control amplifier having a third input connected to the output of the position transducer (31).

Claim 19

System according to claim 14, wherein the control amplifier is an integrating amplifier.

Claim 20

System according to claim 17, wherein the integrating amplifier (25) includes an operational amplifier (250) having an output and an inverting input; and an integrating capacitor (251) connected between the output and the inverting input.

Claim 21

System according to claim 18, (FIG. 9), wherein the gas analysis means (23) is interconnected with the inverting input of the operational amplifier (250).

Claim 22

System according to claim 18, further comprising a position transducer (31) coupled to the main throttle shaft (34) to provide a signal representative of main throttle shaft deflection; a first transistor (257) interconnecting the output of the position transducer (31) and the inverting input of the operational amplifier (250); a series connection formed of an inverting amplifier (261) and a second transistor (258) connected in parallel to the first transistor; said transistors being of opposite conductivity types.

Claim 23

System according to claim 20, further comprising a threshold switch (262, 263) connected to the gas analysis means (23), the output of the threshold switch being connected to the base electrodes of the first and second transistors (257, 258).

Claim 24

System according to claim 21, wherein the threshold switch comprises an operational amplifier (262) having a resistor (263) in the feedback circuit from the output to the non-inverting input thereof.

Claim 25

System according to claim 8, wherein the means (18) connecting the flow of additional air comprises a bypass valve having an electro-mechanical positionable valve cone (63) and a mechanically movable valve seat (100); and drive means (102) operatively interconnecting the means controlling flow of air in the first path and the mechanically movable valve seat to move the valve seat in accordance with change in position of said flow control means.

Claim 26

System according to claim 23, wherein the flow control means for the first path comprises a throttle and a throttle shaft and the drive means comprises a cam (102) interconnected with the throttle shAft.

Claim 27

System according to claim 8, wherein the electro-mechanical control means comprises a common electro-magnetic means responsive both to the amount of air flowing in the first path and further to said electrical sensing signal.

Claim 28

System according to claim 25, wherein the electro-mechanical means comprises control amplifier means and an electro-magnetic valve; said valve forming the means controlling the flow of additional air and comprising a valve seat (62); a valve cone (63, 63'') movable with respect to the valve seat; magnet means (69) having an air gap; and a coil adapted to move with respect to the air gap secured to the valve cone, and connected to said control amplifier means.

Claim 29

System according to claim 26, wherein the air gap has an axially non-linear cross section.

Claim 30

System according to claim 25, wherein the electro-mechanical means comprises control amplifier means and an electromagnetic valve; said valve forming the means controlling the flow of additional air and comprising a valve seat (62); a valve cone (63) movable with respect to the valve seat; electro-magnetic means having an air gap; an energizing coil (78) for said electromagnetic means; and an armature adapted to move with respect to the air gap secured to the valve cone (63), the energzing coil being connected to said control amplifier.

Claim 31

System according to claim 28, wherein the air gap is toroidal and has an axially non-linear cross section.

Claim 32

System according to claim 25, wherein the electro-mechanical means comprises a control amplifier means and an electro-magnetic valve, said valve forming the means controlling the flow of additional air and comprising a valve seat (62); a valve cone (63) movable with respect to the valve seat; electro-magnetic means controlling the movement of the valve cone and being connected to said control amplifier means.

Claim 33

System according to claim 30, wherein the valve cone (63) has a non-linear side contour to provide a non-linear characteristic of displacement with respect to flow through the valve.

Claim 34

System according to claim 30, comprising a guide rod (66) guiding the movement of the valve cone (63); a pair of leaf springs (85, 86) securing the guide rod in position in the electro-magnetic valve free from sliding friction.

Claim 35

System according to claim 30, wherein the electro-magnetic valve has a magnet assembly (69); a membrane (82) is located to seal the space between the magnet assembly (69) and the valve seat (62), the membrane being connected with the means moving the valve cone by gas-tight connection; and a pressure equalization opening bridging the membrane.

Claim 36

System according to claim 33, wherein a guide rod (66) is provided secured to the valve cone and guiding the movement of the valve cone (63) of the electro-magnetic valve; and wherein the pressure equalization opening comprises a central bore (81) in the guide rod bridging the region of the membrane and connecting both sides of the membrane (82), the flow resistance of said bore bridging the opening being high with respect to the flow resistance of the valve.

Claim 37

System according to claim 26, wherein the control amplifier means comprises a control amplifier (25) and a power amplifier (63) connected to the output of the control amplifier; the control amplifier being connected to the gas analysis means and providing a signal representative of oxygen content in the exhaust gas to the power amplifier; and additional signal input means are provided connected to at least one of said amplifiers.

Claim 38

System according to claim 35, comprising transducer means (31) connected to the internal combustion engine and providing an engine control output signal representative of engine controller position.

Claim 39

System according to claim 35, further comprising speed transducer means (32, 33) connected to the internal combustion engine (11) and providing a speed output signAl representative of engine speed.

Claim 40

System according to claim 36, wherein the additional input signal means is connected to the engine control output signal.

Claim 41

System according to claim 36, wherein the additional signal input means is connected to the speed output signal.

Claim 42

System according to claim 36, wherein the control amplifier (25) has two additional inputs, one additional input being connected to a command source (27) representative of a commanded air-fuel relationship ( lambda ); transducer means (31) are provided connected to the internal combustion engine and providing an engine control output signal representative of engine controller position, the engine control output signal being connected to the other additional input.

Claim 43

System according to claim 8, wherein the electro-mechanical control means comprises a common electro-magnetic means responsive both to the amount of air flowing in the first path and further of said electrical sensing signal, said electro-magnetic means including control amplifier means and an electro-magnetic valve, said valve forming the means controlling the flow of air; said valve comprising a valve seat (62) and a valve cone (63) movable with respect to the valve seat; cup-shaped magnetic means (69) having a toroidal air gap, and coil means (97) movable within the air gap; an operating rod (66) connected to said coil means, the magnetic means being an electromagnet having an energizing coil (98), said energizing coil and the movable coil being controlled by said control amplifier means.

Claim 44

System according to claim 41, comprising a pair of power amplifiers (95, 96), one power amplifier each being connected to the movable coil and to said magnet coil; and control circuit means controlling said power amplifiers forming said control amplifier means and comprising summing circuit means (90, 91, 92) applying electrical voltages representative of said electrical sensing signal (23, 24) and of operating parameters (31; 32, 33) of the engine applied to one power amplifier and adding resistors (93, 94) being connected to the other power amplifier and having signals representative of operating parameters of the engine (31; 32, 33) applied thereto.

Claim 45

System according to claim 42, wherein the signals representative of operating parameters of the engine comprise signals representative of at least one of: commanded engine controller position; engine speed.

Claim 46

System according to claim 8, wherein the exhaust gas analysis means comprises an oxygen sensor (23) including an oxygen ion conductive solid eletrolyte and providing two surfaces, one surface being exposed to the exhaust gases from the engine and the other surface being exposed to ambient air; the surfaces having microporous platinum layers (43) applied thereto; and contact means contacting the two platinum layers at the two sides of the solid electrolyte.

Claim 47

System according to claim 44, wherein the oxygen ion conductive solid electrolyte comprises zirconium dioxide.