In various aspects, internal combustion engines, engine controllers and methods of controlling engines are described. The engine includes a camshaft and a two cylinder sets. Cylinders in the first are deactivatable and cylinders in the second set may be fired at high or low output levels. The air charge for each fired working cycle is set based on whether a high or low torque output is selected. In some implementations, the camshaft is axially shiftable between first and second positions. First cam lobes are configured to cause their associated cylinders to intake a large air charge during intake strokes that occur when the camshaft is in the first position. Second cam lobes for cylinders in the second set cause their associated cylinders to intake a smaller air charge when the camshaft is in the second position. Second cam lobes for cylinders in the first set deactivate their associated cylinders.

Methods and systems are provided for improving fuel vapor storage canister purging operations for vehicles with dual-path purge systems. In one example, a method may include purging fuel vapors from a fuel vapor storage canister to an engine of a vehicle via a single path, and in response to an unmetered increase in a concentration of the fuel vapors being purged to the engine via the single path, switching the fuel vapors to be purged to the engine via two paths simultaneously. In this way, fuel vapors may be distributed in time along the two paths, which may lower an effective concentration of fuel vapors entering the engine and may thereby avoid degradation of engine operating conditions.

An abnormality detection device for an air-fuel ratio sensor is provided. An air-fuel ratio sensor is provided in an exhaust passage. A storage device stores mapping data specifying a mapping. The mapping outputs an abnormality determination variable using first time series data and second time series data as an input. The first time series data is time series data of an excess amount variable in a first predetermined period. The excess amount variable is a variable corresponding to an excess amount of fuel actually discharged to the exhaust passage in relation to an amount of fuel reacting without excess or deficiency with oxygen contained in a fluid discharged to the exhaust passage. The second time series data is time series data of an air-fuel ratio detection variable in a second predetermined period.

In various aspects, internal combustion engines, engine controllers and methods of controlling engines are described. The engine includes a camshaft and a two cylinder sets. Cylinders in the first are deactivatable and cylinders in the second set may be fired at high or low output levels. The air charge for each fired working cycle is set based on whether a high or low torque output is selected. In some implementations, the camshaft is axially shiftable between first and second positions. First cam lobes are configured to cause their associated cylinders to intake a large air charge during intake strokes that occur when the camshaft is in the first position. Second cam lobes for cylinders in the second set cause their associated cylinders to intake a smaller air charge when the camshaft is in the second position. Second cam lobes for cylinders in the first set deactivate their associated cylinders.

An air amount control valve of a vehicle changes an intake air amount drawn into a cylinder. A fuel cutoff process stops fuel injection from a fuel injection valve when stopping combustion in the cylinder in a case in which a crankshaft is rotating. When execution of the fuel cutoff process is requested, a temperature-increase limiting process is executed to draw fresh air into a catalyst by increasing the intake air amount through control of the air amount control valve. In a case in which an anomaly occurs in driving of the air amount control valve when executing the temperature-increase limiting process, an amount of air drawn into the catalyst is increased by increasing an engine speed.

The present invention concerns a method in a two-stroke engine comprising at least one cylinder (1) with a reciprocating piston (2), a delimited combustion space (5), at least one outlet port (7) and an inlet port (9) which are both uncovered at the bottom dead center position of the piston, an actuator (8) which activates a valve (17) to open and introduce combustion air via an inlet pipe (6), a control system (15) which controls the actuator to open the valve in order to introduce combustion air via the inlet port. The invention is characterized in that the inlet port is closed by the piston after the outlet port has been closed, thus the opposite compared to the two-stroke engines of today.

Passage-separated intake of the present invention refers to that a separate supercharged intake passage and a separate supercharged intake supply apparatus are provided such that natural intake is separated from supercharged intake to implement respective intake without mutual interference. Time-separated intake refers to that in order to avoid a cylinder C from becoming a passage between natural intake and supercharged intake, natural intake is performed first in an intake stroke, and supercharged intake is performed after a bottom dead center of the intake stroke at the end of the natural intake. The efficiency of supercharged intake in this case is <100%. The supercharged intake is that an ECU controls the timing of intake performed by a supercharged electromagnetic gas valve V according to a signal from a crankshaft position sensor SQ. As data about a supercharged intake amount at different rotational speeds of an internal combustion engine has been input to the ECU, the ECU controls, according to a signal from a crankshaft speed sensor SR, the supercharged electromagnetic gas valve V to inject a corresponding amount of air into the cylinder C, so as to change a compression ratio by changing the supercharged intake amount.

A misfire detection device for an internal combustion engine includes a storage device and processing circuitry, the storage device stores first mapping data corresponding to a case where a warm-up process of a catalyst provided in an exhaust passage of an internal combustion engine is being executed, and second mapping data corresponding to a case where the warm-up process is not being executed, and each of the first mapping data and the second mapping data uses a rotation waveform variable as an input and defines a mapping that outputs a misfire variable that is a variable related to a probability misfire has occurred. The rotation waveform variable is a variable indicating a difference between a plurality of values of an instantaneous speed variable respectively corresponding to a plurality of different minute angular intervals.

A mixture supply system with quantitative mixture control comprises a charging system connectable to an internal combustion engine, comprising a bypass and a bypass valve, and a valve train for periodically actuating an intake valve of the internal combustion engine. A valve control time of the intake valve is controllable by the valve train. The system is configured to at least partially close the bypass valve and change the valve control time for extending the valve opening duration upon increase of an engine load, to at least partially open the bypass valve during and/or after expiration of a valve train latency time, and/or to at least partially open the bypass valve and change the valve control time for decreasing the valve opening duration upon an decrease of an engine load, and to at least partially close the bypass valve during and/or after expiration of a valve train latency time.

An abnormality detection device for an air-fuel ratio sensor is provided. An air-fuel ratio sensor is provided in an exhaust passage. A storage device stores mapping data specifying a mapping. The mapping outputs an abnormality determination variable using first time series data and second time series data as an input. The first time series data is time series data of an excess amount variable in a first predetermined period. The excess amount variable is a variable corresponding to an excess amount of fuel actually discharged to the exhaust passage in relation to an amount of fuel reacting without excess or deficiency with oxygen contained in a fluid discharged to the exhaust passage. The second time series data is time series data of an air-fuel ratio detection variable in a second predetermined period.