Quick warm-up intake manifold

Claim 2

A fuel supply system for an internal combustion engine of the type including an intake manifold having a cross-over passageway therein including a thin plate stove exposed on one surface thereof to air-fuel flow to the intake manifold and to exhaust flow on the opposite surface thereof through the cross-over passageway, the improvement comprising: vacuum actuated heat riser valve means having an opened and a closed position, a thermally responsive vacuum control device having means sensing the engine coolant temperature and valve means responsive thereto to selectively direct vacuum to the vacuum actuated heat valve means below a predetermined coolant temperature for maintaining it in its closed position to divert exhaust flow through the crossover passageway during an early fuel evaporation phase of control and operative above the predetermined coolant temperature to direct atmospheric pressure to the heat valve means to open the heat riser valve means to reduce exhaust flow through the crossover passage following the early fuel evaporation phase of operation, a carburetor including a choke for supplying an airfuel mixture to the intake manifold, means including a vacuum operator to pull the choke open to a start position immediately after the engine has started, and means for continuing opening of the choke at a reduced rate from the start position to a full open position following a predetermined time period, said vacuum operated heat riser valve means maintaining heat flow to the stove during the choke opening period and for a period thereafter to assure vaporization of liquid fuel droplets flowing from the carburetor against the stove, said thermally responsive vacuum control device conditioning said heat riser valve means upon a predetermined increase in engine coolant temperature to open said riser valve means to prevent the heating of the stove and airfuel flow into excessive engine once the engine is at a predetermined temperature as reflected by the predetermined increase in engine coolant temperature.

Claim 3

A fuel control system for an internal combustion engine including an intake manifold having a crossover exhaust passageway therein and a thin plate stove therebetween heated by exhaust flow through the crossover passageway to evaporate liquid fuel droplets accumulated on the stove comprising: means including a heat riser valve for diverting engine exhaust through the crossover passage, first vacuum operator means for operating said heat riser valve between first and second positions, a thermal vacuum controller including means for sensing engine coolant temperature and means operative in response to changes in coolant temperature to selectively connect said first vacuum operator with atmosphere and a source of vacuum to move said heat riser valve between its first and second positions, a carburetor for supplying fuel to the intake manifold including a choke having a closed position, a start position and a fully opened position, second vacuum operator means connected to said choke responsive to the intake manifold pressure at engine start to position said choke in its start position to cause an enriched air-fuel mixture into the intake manifold, and means including third vacuum operator means for operating said choke into its fully opened position a predetermined time period after engine start to reduce the fuel enrichment, said thermal vacuum controller being operative when engine coolant is below a predetermined temperature to connect said first vacuum operator means with a source of vacuum to cause said heat riser valve to direct exhaust through the crossover passageway to produce a transfer of heat through the thin plate stove to evaporate liquid fuel droplets during the enriched phase of choke operation, said first diaphragm operator means being conditioned by said thermal vacuum controller to control the heat riser valve to continue exhaust heat flow to the stove folLowing positioning of the choke plate in its fully opened position, said thermal vacuum controller being operative when a predetermined temperature occurs in the engine coolant to condition said first vacuum operator means and said heat riser valve to terminate exhaust flow through the crossover passageway thereby to prevent excessive heating of the air-fuel mixture into the intake manifold following the fuel enrichment period of choke operation.

Claim 4

A fuel control system for an internal combustion engine including an intake manifold having a crossover exhaust passageway therein and a thin plate stove therebetween heated by exhaust flow through the crossover passageway to evaporate liquid fuel droplets accumulated on the stove comprising: means including a heat riser valve for diverting engine exhaust through the crossover passage, first vacuum operator means for operating said heat riser valve between first and second positions, a thermal vacuum controller including means for sensing engine coolant temperature and means operative in response to changes in coolant temperature to selectively connect said first vacuum operator with atmosphere and a source of vacuum to move said heat riser valve between its first and second positions, a carburetor for supplying fuel to the intake manifold including a choke having a closed position, a start position and a fully opened position, second vacuum operator means connected to said choke responsive to the intake manifold pressure at engine start to position said choke in its start position to cause an enriched air-fuel mixture into the intake manifold, and means including third vacuum operator means for operating said choke into its fully opened position a predetermined time period after engine start to reduce the fuel enrichment, said thermal vacuum controller being operative when engine coolant is below a predetermined temperature to connect said first vacuum operator means with a source of vacuum to cause said heat riser valve to direct exhaust through the crossover passageway to produce a transfer of heat through the thin plate stove to evaporate liquid fuel droplets during the enriched phase of choke operation, said first diaphragm operator means being conditioned by said thermal vacuum controller to control the heat riser valve to continue exhaust heat flow to the stove folLowing positioning of the choke plate in its fully opened position, said thermal vacuum controller being operative when a predetermined temperature occurs in the engine coolant to condition said first vacuum operator means and said heat riser valve to terminate exhaust flow through the crossover passageway thereby to prevent excessive heating of the air-fuel mixture into the intake manifold following the fuel enrichment period of choke operation.

Claim 5

A fuel supply system for an internal combustion engine of the type including an intake manifold having a cross-over passageway therein for the flow of exhaust heat from the engine and including a heat transfer plate between the crossover passageway and the intake manifold to evaporate liquid fuel droplets flowing into the intake manifold from a carburetor, the improvement comprising: a choke in said carburetor, a first diaphragm operator for positioning said choke in a closed and a break position following start, means including a second vacuum operator connected to said choke and operative following the start of an engine to pull the choke from the vacuum break position to a full open position through a controlled time period to produce a quick opening of the choke after the engine has started, a third vacuum operator, heat riser valve means connected to said third vacuum operator, and thermal vacuum valve means including a thermally responsive element for sensing the coolant temperature of the vehicle and operative to condition said third vacuum operator to position the heat riser valve means in a heat position during a start phase of operation whereby exhaust heat is directed against the heat transfer plate for causing liquid fuel droplets thereon to evaporate, said thermal vacuum valve means being responsive to a predetermined increase in coolant temperature to position the heat riser valve means in a bypass position to cause less exhaust flow through the crossover passageway thereby to reduce the input of heat into the intake manifold to prevent excessive heating of the air-fuel mixture passing therethrough, said heat riser valve being maintained in its heat position for a time period in excess of the choke controlled time period to maintain transfer of exhaust heat to the heat transfer plate during enriched fuel phase of choke operation whereby liquid fuel particles accumulated on the heat transfer plate are subjected to early fuel evaporation to prevent excessive emissions from the engine during cold start operation of the engine.

Claim 6

A fuel supply system for an internal combustion engine of the type including an intake manifold having a cross-over passageway therein for the flow of exhaust heat from the engine and including a heat transfer plate between the crossover passageway and the intake manifold to evaporate liquid fuel droplets flowing into the intake manifold from a carburetor, the improvement comprising: a choke in said carburetor, a first diaphragm operator for positioning said choke in a closed and a break position following start, means including a second vacuum operator connected to said choke and operative following the start of an engine to pull the choke from the vacuum break position to a full open position through a controlled time period to produce a quick opening of the choke after the engine has started, a third vacuum operator, heat riser valve means connected to said third vacuum operator, and thermal vacuum valve means including a thermally responsive element for sensing the coolant temperature of the vehicle and operative to condition said third vacuum operator to position the heat riser valve means in a heat position during a start phase of operation whereby exhaust heat is directed against the heat transfer plate for causing liquid fuel droplets thereon to evaporate, said thermal vacuum valve means being responsive to a predetermined increase in coolant temperature to position the heat riser valve means in a bypass position to cause less exhaust flow through the crossover passageway thereby to reduce the input of heat into the intake manifold to prevent excessive heating of the air-fuel mixture passing therethrough, said heat riser valve being maintained in its heat position for a time period in excess of the choke controlled time period to maintain transfer of exhaust heat to the heat transfer plate during enriched fuel phase of choke operation whereby liquid fuel particles accumulated on the heat transfer plate are subjected to early fuel evaporation to prevent excessive emissions from the engine during cold start operation of the engine.

Claim 7

A vehicle fuel supply system comprising an intake manifold having a floor, a carburetor for directing air-fuel ratio into the intake manifold downwardly against said floor, said carburetor including a choke plate, a thin metal plate in the floor of the intake manifold, means for directing exhaust gas under the plates through a constricted passage, means including a heat riser valve for opening and closing communication between the engine exhaust valves and the constricted passage, first vacuum operator means for operating the heat riser valve, thermal vacuum control means including means sensing the engine coolant temperature and means operative to condition the vacuum operator means to open the heat riser valve when the coolant reaches a predetermined temperature, second vacuum operator means in communication with intake manifold vacuum through means including a restriction for delaying operation of said second vacuum operator means, means for coupling said second vacuum operator means to the choke, said second vacuum operator being responsive to operation of the engine following engine start to open the choke during a quick response period, said thermal vacuum control means controlling vacuum to the first vacuum operator to maintain the heat riser valve conditioned to direct exhaust heat through the constricted passageway during enriched fuel operation to evaporate liquid fuel particles directed against the thin metal plate, said thermal vacuum control means being operative to apply manifold Vacuum to the first vacuum operator means above a predetermined temperature following a time duration in excess of that required to position said choke in its full open position to terminate exhaust heating of the plates thereby to prevent excessive temperature increases in the air-fuel mixture to the engine following the enriched fuel phase of operation, said heat riser valve including means responsive to a low vacuum produced on full throttle positions in the intake manifold before the thermal vacuum valve senses a predetermined switchover temperature thereby to permit exhaust of gas from the engine to improved engine power and to limit manifold plate temperatures under full throttle conditions.

Claim 8

A vehicle fuel supply system comprising an intake manifold having a floor, a carburetor for directing air-fuel ratio into the intake manifold downwardly against said floor, said carburetor including a choke plate, a thin metal plate in the floor of the intake manifold, means for directing exhaust gas under the plates through a constricted passage, means including a heat riser valve for opening and closing communication between the engine exhaust valves and the constricted passage, first vacuum operator means for operating the heat riser valve, thermal vacuum control means including means sensing the engine coolant temperature and means operative to condition the vacuum operator means to open the heat riser valve when the coolant reaches a predetermined temperature, second vacuum operator means in communication with intake manifold vacuum through means including a restriction for delaying operation of said second vacuum operator means, means for coupling said second vacuum operator means to the choke, said second vacuum operator being responsive to operation of the engine following engine start to open the choke during a quick response period, said thermal vacuum control means controlling vacuum to the first vacuum operator to maintain the heat riser valve conditioned to direct exhaust heat through the constricted passageway during enriched fuel operation to evaporate liquid fuel particles directed against the thin metal plate, said thermal vacuum control means being operative to apply manifold Vacuum to the first vacuum operator means above a predetermined temperature following a time duration in excess of that required to position said choke in its full open position to terminate exhaust heating of the plates thereby to prevent excessive temperature increases in the air-fuel mixture to the engine following the enriched fuel phase of operation, said heat riser valve including means responsive to a low vacuum produced on full throttle positions in the intake manifold before the thermal vacuum valve senses a predetermined switchover temperature thereby to permit exhaust of gas from the engine to improved engine power and to limit manifold plate temperatures under full throttle conditions.