Patent GB-1519325-A (GB)
Title: Multiple-cylinder spark-ignition internal combustion engine with exhaust gas afterburning
IPC: F02P5/145
Filed: 1975-10-03
Abstract: 1519325 IC engines NISSAN MOTOR CO Ltd 3 Oct 1975 [3 Oct 1974] 40545/75 Heading F1B [Also in Divisions Bl and F4]  An I.C. engine 10 has first and second groups of cylinders, e.g. three cylinders per group, supplied with rich and lean mixtures, respectively, and the exhaust gases from the cylinders are supplied to a common afterburning chamber 16. The chamber 16 is surrounded by an air jacket 68 through which air from a blower 76 is directed when the temperature sensed by a temperature responsive switch on the jacket exceeds a predetermined value. Air from the jacket 68 is fed to the air cleaner 48 under the control of a valve 86 operated by a diaphragm motor 88 connected to the intake manifold 40 via a valve 100 operated in response to the air temperature in the air cleaner. An engine-driven air pump 104 supplies air to the engine exhaust passages 30 under the control of valve units 122, 124 closing a flow-path 108, 108b to atmosphere through an outlet 126 or opening the flow-path by a valve 122e or a valve 124e and a restrictor 126a. The engine spark-plugs are connected to at least one distributer 168 providing normal or retarded ignition timing. The operation of the valve units 122, 124 and the distributer is controlled by relays 142 and 144 and a switch 146 linked to the carburetter choke valve 54. The switch 146 is connected between the alternator 132 and its regulator 136. In operation for engine starting the switch 146 is closed and the alternator 132 provides no power to energize the relay coil 144a. With the relay contacts 144c open the normal advance distributer contacts 180 are operative and the relay contacts 144b are open so that three-way valve 118 controlling the supply of manifold vacuum to the actuating chambers 122b, 124b is not energized. The valves 116, 118 provide communication of the actuator chamber 122b with atmosphere and the chamber 124b with the manifold when de-energized. With the engine started the alternator output energizes the relay 144 and the retarded distributor contacts 182 become operative and the valve 118 is energized to connect the actuator chamber 124b to atmosphere and permit the spring 124f to close the valve 124e. Opening of the choke valve 54 manually by the knob 58 or automatically in response to a thermostatic spring de-energizes the relay 144 and the normal timing contacts 182 become operative and the valve 124b is opened. When the switch 140 closes on overheating in the chamber 16 the relay 142 is energized and the blower 76 and the valve 116 are energized. With the valve energized the actuator chamber 122b is connected to the manifold 40 and the valve 122e opens to vent the air from the pump 104 to the atmosphere. The blower 76 provides a flow of air to jacket 68, a jacket 80 around the exhaust pipe 20 and a discharge port 82. A valve 129a opens above a predetermined manifold vacuum to supply air to the manifold 40 on overrunning. In a second embodiment, Figs. 4a and 4b (not shown), the nozzles 114 for injecting air into the engine exhaust passages 30 are connected to the air cleaner 48 via a valve (204) which is closed with the choke valve 54 and the outlet of the blower 76 via a non-return valve (208). The outlet of the blower 76 contains a valve (212), downstream of the connection to the nozzles 114, which is closed when the choke valve is closed. A relay (216) in the blower circuit is closed to energize the blower when the relay (244) controlled by the switch 146 and the alternator output is energized. The spark-plugs of the two groups of cylinders may be connected to respective distributers (168a, 168b), Figs. 5 and 6 (not shown), providing respective normal and retarded ignition timings.