Nissan Motor Company Limited

Hitachi, Ltd.

Junichiro Matsumoto

Haruhiko Iizuka

Fukashi Sugasawa

Fumiaki Kato

Yukihiro Etoh

Kenji Maio

Yasuhisa Takeuchi

Nagayuki Marumo

Haruhiko Itzuka

An electronic controlled fuel injection system is disclosed for use in an internal combustion engine including a plurality of cylinders each fitted with a fuel injection valve. The system comprises a fuel injection control circuit timed to engine rotation for providing a drive pulse signal to the fuel injection valves. A deceleration detecting circuit detects deceleration of the engine in accordance with the positions of the associated throttle valve and foot brake. A coupling circuit is responsive to engine rotational speed for allowing or impeding the passage of the drive pulse signal to the fuel injection valves during deceleration.

Electronic controlled fuel injection system

Apparatus for controlling the number of enabled cylinders of an internal combustion engine during deceleration comprises a plurality of comparators responsive to a signal indicative of the engine rotational speed upon deceleration of the engine. The threshold voltages of the comparators are arranged stepwise so that each comparator produces an output signal when the engine speed falls below each threshold voltage. The output signals of the comparators are supplied to logic circuits to control a plurality of switches via which the fuel injection control pulse signal is respectively applied to fuel injection valves to increase in a stepwise fashion the number of enabled cylinders from the fuel cut-off state thereby preventing occurrence of impacts or shocks in the transition period of reactivation of the cylinders upon deceleration.

Apparatus for controlling the number of enabled cylinders of an internal

The engine crankshaft rotational speed is detected to be compared with stepwise arranged threshold speeds so as to stepwise enable fuel injection valves of respective cylinders during deceleration of the engine. Accordingly, the number of enabled cylinders is increased in a stepwise manner from a fuel cut-off state as the engine rotational speed decreases to prevent engine stall, while occurrence of shocks upon reactivation of cylinders is avoided. The threshold speeds are controlled in accordance with the variation of engine load which may be increased upon operation of auxiliary power consuming units, such as an air conditioner the compressor of which is driven by the engine, for preventing undesirable vibrations of the engine during the stepwise reactivation of the cylinders.

Apparatus for performing stepwise reactivation of cylinders of an

A control system for a multi-cylinder internal combustion engine comprises a split engine control unit for operating the engine on partial cylinders when reduced engine power can adequately operate the vehicle, and first and second upstream exhaust conduits for directing exhaust gases from first and second group cylinders respectively to a common junction to which a downstream exhaust conduit is connected for emitting the gases to the atmosphere. A first set of an exhaust gas sensor and catalytic converter is disposed in the first conduit to be exposed to the stream of gases exhausted from the second group cylinders which are activated at all times and a second set of an exhaust gas sensor and catalytic converter is disposed in the common downstream conduit to be exposed to the stream of gases exhausted from the first group cylinders directed through the first conduit and to the gases passed through the upstream catalytic converter in the second conduit. A feedback control circuit is responsive selectively to a signal from the first gas sensor during the partial cylinder operation for correcting the mixture ratio to a rich side of stoichiometry to promote reduction of the NOx component in the upstream converter and oxidation of HC and CO components in the downstream converter, and to a signal from the second gas sensor during the full cylinder operation for correcting the mixture ratio to a point at or near stoichiometry to promote simultaneous reduction and oxidation processes in both of the converters.

Combined split engine and closed loop mixture control operation with

A control system for a multi-cylinder internal combustion engine comprises a split engine control unit for operating the engine on partial cylinders when reduced engine power can adequately operate the vehicle, and first and second exhaust conduits for directing exhaust gases from first and second group cylinders respectively to a common junction to which a common exhaust conduit is connected for directing the gases to the atmosphere. A first set of an exhaust gas sensor and catalytic converter is disposed in the second conduit to be exposed to the stream of gases exhausted from the second group cylinders which are activated at all times and a second set of an exhaust gas sensor and catalytic converter is disposed in the common conduit to be exposed to the stream of gases exhausted from the first group cylinders directed through the first conduit and to the gases passed through the upstream side catalytic converter in the second conduit. Feedback mixture control operation is effected on the basis of the signal from the first exhaust gas sensor during the partial cylinder mode and a full cylinder mode in which the second gas sensor is still below its normal operating temperature. The signal from the second gas sensor is utilized for the feedback operation in the full cylinder mode in which the temperature of the latter sensor is above its normal operating point.

Combined split engine and feedback controlled engine operations

Disclosed is a split engine control system wherein the intake manifold is segmented by a shut-off valve into a first chamber portion leading to a first group of cylinders and a second chamber portion leading to a second group of cylinders. During periods of relatively low load, the cylinders of the second group are deactivated and the shut-off valve is closed to isolate the second chamber from the first chamber to cut off air supply to the deactivated cylinders. Exhaust gases are recirculated through the deactivated cylinders so that their pumping loss is minimized. A pressure detector is provided to detect a pressure difference which might develop between the first and second chambers during the partial cylinder operation to control the flow rate of the recirculated gases until the pressure difference reduces substantially to zero.

Split engine control system with exhaust gas recirculation

A control system for a multi-cylinder internal combustion engine comprises a split engine control unit for operating the engine on partial cylinders when reduced engine power can adequately operate the vehicle, and first and second upstream exhaust conduits for directing exhaust gases from first and second group cylinders respectively to a common junction to which a common downstream exhaust conduit is connected for emitting the gases to the atmosphere. A first catalytic converter is disposed in the second exhaust conduit to be exposed to the stream of gases exhausted from the second group cylinders which are activated at all times and a second catalytic converter is disposed in the common downstream conduit to be exposed to the stream of gases exhausted from the first group cylinders directed through the first conduit and to the gases passed through the first catalytic converter. An exhaust gas sensor is provided in the common exhaust conduit upstream of the downstream converter. A feedback control circuit is responsive to signals from the gas sensor to effect closed loop mixture control in which the air-fuel mixture supplied to all the cylinders during the full cylinder mode is controlled to the stoichiometric point so that both converters each promote simultaneous reduction of the NOx component and oxidation of the HC and CO components. A feedback control disabling circuit is provided which is effective during the partial cylinder mode for controlling the air-fuel ratio to the rich side of the stoichiometric point to promote reduction of the NOx component in the first converter and oxidation of the HC and CO components in the second converter.

Stoichiometric and enrichment mixture control during different split

A split engine control system includes a load level detector for generating a first signal in response to a relatively high engine load and a second signal in response to a relatively low engine load. A certain of the cylinders of an internal combustion engine is deactivated in response to the second signal to operate the engine on partial cylinders and activated in response to the first signal to permit the engine to operate on full cylinders. A discriminating circuit is connected to the load level detector to disable the second signal when the duration of the latter is smaller than a preset time interval which corresponds to the duration of a false indication of engine load reduction which might occur in response to gear changes during full cylinder operation.

Split engine operation with means for discriminating false indication of

In an automatic power transmission system for a multicylinder internal combustion engine wherein the intake vacuum is not available as a true indication of engine load, a detection system for detecting the level of engine load includes an electrical actuator responsive to a signal which faithfully represents the engine load to vary the pressure of fluid in the automatic power transmission system. One embodiment of the invention includes an intake air sensor, an engine speed sensor and a division circuit responsive to the outputs from both sensors to generate a signal representing the quantity of air inducted per unit time to represent the true indication of the engine load free from the effect of exhaust gas recirculation or other factors influencing the intake vacuum.

Engine load detection system for automatic power transmission

Fuel economy of a multi-cylinder internal combustion engine has been improved by allowing, when a vehicle is at a standstill, the engine to run on selected cylinders of all. The idling operation of the engine on the selected cylinders has been made smooth by the provision of a switch valve in a control circuit of the transmission. With the switch valve, as soon as an accelerator pedal is released when the vehicle is at a standstill, hydraulic fluid will be drained from the control circuit to render a gearing of the transmission in a neutral condition even if a manually selector valve in the control circuit is held in a drive range position. This prevents transmission of load to the engine through the hydrokinetic unit which otherwise would occur when the manually selector valve is in the drive range position.

Apparatus for improving fuel economy of multi-cylinder I. C. engine

An internal combustion engine of the type wherein a particular group of engine cylinders are not supplied with air-fuel mixture during light load engine operation, comprises a gas supply device for supplying exhaust gas or fresh air into the particular group of cylinders when not supplied with air-fuel mixture, and a control device for stopping the supply of the exhaust gas or fresh air when a brake pedal is depressed to slow down the speed of a motor vehicle, so that engine brake becomes effective or is improved during light load engine operation.

Internal combustion engine for motor vehicle

In an internal combustion engine, the magnitude of the engine load is compared with a reference level which is variable as a function of engine speed to detect when the engine load under low speed operation is small in proportion to the engine speed. Under these circumstances, fuel supply to a portion of the cylinders is blocked to allow the engine to run on a lesser number of cylinders so that fuel economy is achieved.

Method and apparatus for disabling cylinders under light load conditions

In a variable displacement internal combustion engine, a pair of cylinder groups are alternately switched into deactivation for fuel economy when reduced power output can operate the vehicle adequately at an appropriate timing detected when engine output power is at maximum or minimum so that harmful effect on engine performance is minimized during switching periods.

Variable displacement internal combustion engine with means  for

In an automatic brake controller having a vehicle velocity detector for detecting vehicle velocity and a wheel velocity detector for detecting wheel velocity, a failure detecting system is provided for the vehicle velocity detector and the wheel velocity detector. A comparator which makes a comparison between the vehicle velocity signal obtained from said vehicle velocity detector and the wheel velocity signal obtained from said wheel velocity detector generates a predetermined output signal when the difference between both the output signals of said detectors exceeds a predetermined value, and a logical circuit is responsive to said output signal from said comparator to provide a failure signal when a signal representative of a normal transit condition is being generated.

System for detecting a failure in a vehicle velocity detector and a

A vehicle controlling device wherein an output signal proportional to vehicle velocity obtained from a vehicle velocity detector and an output signal proportional to wheel velocity obtained from a wheel velocity detector are to be compared by a comparator and the slip state of the wheel is to be detected from the result of the comparison, thereby to control a brake mechanism, characterized in that an adder circuit is provided which adds an output signal proportional to a predetermined wheel velocity at a low vehicle running speed to the output signal obtained from the wheel velocity detector and that the output signal of the adder circuit and the output signal from the vehicle velocity detector are compared by the comparator to ensure accurate brake control at all vehicle speeds.

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Yokosuka, Japan

Junichiro Matsumoto