Abstract: An internal combustion engine system includes a first set of cylinders, a second set of cylinders, exhaust manifolds, and exhaust gas sensors. The first set of cylinders has first and second subsets of cylinders. The second set of cylinders has third and fourth subsets of cylinders. The exhaust manifolds have primary conduits, secondary conduits branching from the primary conduits, and tertiary conduits branching from the secondary conduits. The tertiary conduits associated with each of the secondary conduits are connected to one of the first, second, third, or fourth subsets of cylinders. The exhaust gas sensors are disposed within each of the secondary conduits and are each configured to measure air-to-fuel ratios of one of the first, second, third, or fourth subsets of cylinders.

Abstract: An internal combustion engine system includes a first set of cylinders, a second set of cylinders, exhaust manifolds, and exhaust gas sensors. The first set of cylinders has first and second subsets of cylinders. The second set of cylinders has third and fourth subsets of cylinders. The exhaust manifolds have primary conduits, secondary conduits branching from the primary conduits, and tertiary conduits branching from the secondary conduits. The tertiary conduits associated with each of the secondary conduits are connected to one of the first, second, third, or fourth subsets of cylinders. The exhaust gas sensors are disposed within each of the secondary conduits and are each configured to measure air-to-fuel ratios of one of the first, second, third, or fourth subsets of cylinders.

Abstract: Methods and systems are provided for a diagnostic routine of a variable displacement engine (VDE) of a vehicle to detect non-deactivated valves of deactivated cylinders due to a degraded valve deactivation mechanism. In one example, a method comprises, during operation of the VDE with one or more cylinders of the VDE deactivated, calculating a variation in a fast-sampled signal outputted by one or more exhaust gas oxygen (EGO) sensors of the VDE over a plurality of engine cycles; determining that the variation is greater than the threshold variation; and in response, indicating that valves of the one or more cylinders are not deactivated. A second method comprises estimating a throttle air flow rate and an engine air flow rate of the VDE; and indicating non-deactivated valves of one or more deactivated cylinders if the throttle air flow rate exceeds the engine air flow rate by a threshold.

Abstract: Various systems and methods are described for deactivation and reactivation of a cylinder bank in a V-engine. In one example, the cylinder bank is deactivated responsive to an indication of misfire based on crankshaft acceleration and exhaust air fuel ratio. The cylinder bank is reactivated sequentially based on exhaust catalyst temperature.

Abstract: Various systems and methods are described for deactivation and reactivation of a cylinder bank in a V-engine. In one example, the cylinder bank is deactivated responsive to an indication of misfire based on crankshaft acceleration and exhaust air fuel ratio. The cylinder bank is reactivated sequentially based on exhaust catalyst temperature.

Abstract: Various systems and methods are described for deactivation and reactivation of a cylinder bank in a V-engine. In one example, the cylinder bank is deactivated responsive to an indication of misfire based on crankshaft acceleration and exhaust air fuel ratio. The cylinder bank is reactivated sequentially based on exhaust catalyst temperature.

Abstract: Various systems and methods are described for deactivation and reactivation of a cylinder bank in a V-engine. In one example, the cylinder bank is deactivated responsive to an indication of misfire based on crankshaft acceleration and exhaust air fuel ratio. The cylinder bank is reactivated sequentially based on exhaust catalyst temperature.

Abstract: A method (42) is disclosed for detecting the usage of a heater (31) in a block (30) of an internal combustion engine (11). The method (42) uses temperature measurements of the engine coolant and any ambient air used to create the air/fuel mixture. Based on the difference between the temperatures, the temperatures are weighted and added to create a temperature variable. The temperature variable is used by the electronic engine control module (34) to create an air/fuel mixture which will allow the internal combustion engine (11) to start smoothly. The method (42) operates on this modified temperature; i.e., the temperature variable, which is not the temperature of the engine coolant, nor the ambient air, and allows for the stoichiometric balance of the air/fuel mixture to be modified to optimize performance of the internal combustion engine (11) during a cold start in cold weather with warm engine coolant.