Methods and systems are provided for detecting air-fuel ratio imbalances across all engine cylinders. In one example, a method (or system) may include indicating cylinder imbalance based on each of the exhaust air-fuel ratio, exhaust manifold pressure, and cylinder torque weighted by a confidence factor, where in the confidence factor is determined based on operating conditions.

A method for managing temperatures in an aftertreatment system positioned downstream of an engine. The method includes (1) combusting a rich air/diesel mixture in a cylinder of the engine, and then (2) combusting a lean air/diesel mixture in the cylinder, in the next combustion event in the cylinder, after combusting the rich air/diesel mixture therein. The method further includes repeating steps (1) and (2) in the cylinder and basing a frequency thereof on a desired aftertreatment system temperature.

An engine system is disclosed. The engine system may have an engine including at least one cylinder. The engine system may also have a first source configured to supply fuel for combustion in the engine. The engine system may have a second source configured to supply ignition promoter material for combustion in the engine. The engine system may also have a droplet generator configured to generate droplets of the ignition promoter material. In addition the engine system may have a controller. The controller may be configured to determine an engine parameter. The controller may also be configured to determine a number of the droplets based on the engine parameter. Further, the controller may be configured to determine droplet sizes of the droplets based on the engine parameter. In addition, the controller may be configured to adjust the droplet generator to generate the number of the droplets having the droplet sizes.

Methods and systems are provided for detecting air-fuel ratio imbalances across all engine cylinders. In one example, a method (or system) may include indicating cylinder imbalance based on each of the exhaust air-fuel ratio, exhaust manifold pressure, and cylinder torque weighted by a confidence factor, where in the confidence factor is determined based on operating conditions.

A method of controlling a concentration of hydrocarbons in exhaust gas from an internal combustion engine includes sensing an oxygen percentage of the flow of exhaust gas from the internal combustion engine and determining a concentration of hydrocarbons in the flow of exhaust gas. An engine control module may then adjust the sensed oxygen percentage of the exhaust gas based on the determined concentration of hydrocarbons in the flow of exhaust gas to define a corrected oxygen percentage. The control module may then control at least one of a hydrocarbon injection rate for in-cylinder combustion of the internal combustion engine, and a hydrocarbon injection rate for a post combustion exhaust gas treatment process, based on the corrected oxygen percentage, to control the concentration of hydrocarbons in the exhaust gas.

A combination system may include a carburetor in fluid communication with an engine intake tract and a fuel injector in fluid communication with the engine intake tract.

In the present invention, an internal combustion engine is provided with an in-cylinder fuel injection valve and a secondary air supply device and is formed so as to make possible first catalyst warming control and second catalyst warming control that promote the raising of the temperature of an exhaust gas purification catalyst. The first catalyst warming control comprises control to inject fuel from the in-cylinder fuel injection valve during the compression stroke to form a stratified state, and control to greatly delay ignition timing. The second catalyst warming control comprises control to supply secondary air to an engine exhaust gas passage. The internal combustion engine executes the first catalyst warming control after startup and, after the first catalyst warming control is executed, carries out control (third catalyst warming control) to execute the first catalyst warming control and the second catalyst warming control simultaneously.

A computing system is disposed remote from a vehicle and communicably coupled to the vehicle over a network. The computing system includes a communications interface, one or more processors, and memory storing instructions that when executed by the one or more processors, cause the one or more processors to receive a first emissions data packet from a vehicle controller, the first emissions data packet including a plurality of emissions values regarding operation of a vehicle; determine whether a first cumulative emissions value is greater than a threshold value; and responsive to determining that the first cumulative emissions value is greater than the threshold, performing, by the remote computing system, corrective operations.

A method of controlling a concentration of hydrocarbons in exhaust gas from an internal combustion engine includes sensing an oxygen percentage of the flow of exhaust gas from the internal combustion engine and determining a concentration of hydrocarbons in the flow of exhaust gas. An engine control module may then adjust the sensed oxygen percentage of the exhaust gas based on the determined concentration of hydrocarbons in the flow of exhaust gas to define a corrected oxygen percentage. The control module may then control at least one of a hydrocarbon injection rate for in-cylinder combustion of the internal combustion engine, and a hydrocarbon injection rate for a post combustion exhaust gas treatment process, based on the corrected oxygen percentage, to control the concentration of hydrocarbons in the exhaust gas.

A control process for controlling an engine speed governor of an engine is provided. The process comprises the steps of calculating the current engine power being developed by the engine, and determining an appropriate engine speed for the current engine power based upon a first engine map. The process then instructs the speed governor to adjust the engine speed in accordance with the first map if required. The process monitors for desired engine power requests, and calculates a power ratio of desired engine power versus current engine power upon receiving a desired engine power request. The process then establishes an engine speed adjustment value based upon a second engine map of power ratio versus speed adjustment value, and instructs the speed governor to adjust the engine speed in accordance with the speed adjustment value. A speed governor system incorporating the control process, and a work machine or vehicle incorporating such a system are also provided.