An exhaust device for a saddle-type vehicle having a pipe section with respect to a vehicle body and housing a catalyzer therein, and a muffler connected to a rear end of the pipe section includes an upstream oxygen sensor disposed on the pipe section and positioned upstream of the catalyzer and a downstream oxygen sensor disposed on the pipe section and positioned downstream of the catalyzer. The pipe section includes a larger-diameter portion having an increased diameter for housing the catalyzer therein. The downstream oxygen sensor is disposed in the larger-diameter portion. The upstream oxygen sensor and the downstream oxygen sensor are positioned upwardly of a central line of the larger-diameter portion with respect to the vehicle body as viewed in side elevation of the vehicle body.

An exhaust device for a saddle-type vehicle having a pipe section with respect to a vehicle body and housing a catalyzer therein, and a muffler connected to a rear end of the pipe section includes an upstream oxygen sensor disposed on the pipe section and positioned upstream of the catalyzer and a downstream oxygen sensor disposed on the pipe section and positioned downstream of the catalyzer. The pipe section includes a larger-diameter portion having an increased diameter for housing the catalyzer therein. The downstream oxygen sensor is disposed in the larger-diameter portion. The upstream oxygen sensor and the downstream oxygen sensor are positioned upwardly of a central line of the larger-diameter portion with respect to the vehicle body as viewed in side elevation of the vehicle body.

A physical quantity measurement device includes a measurement flow path that includes a sensor path in which a physical quantity sensor is disposed, an upstream curved path curved between the sensor path and an inlet, and a downstream curved path curved between the sensor path and an outlet. An inner surface of a housing includes an upstream outer curved surface that defines an outer outline of the upstream curved path, and a downstream outer curved surface that defines an outer outline of the downstream curved path. An arrangement line is an imaginary straight line passing through the physical quantity sensor between the upstream curved path and the downstream curved path. On the arrangement line, a distance between the downstream outer curved surface and the physical quantity sensor is larger than a distance between the upstream outer curved surface and the physical quantity sensor.

An aircraft diesel engine may be operated at a minimal fuel rate. Shaft output power of the engine may be reduced by initiating combustion during the compression stroke. Combustion may be initiated during the compression stroke by advancing fuel injection, splitting fuel injection, and/or manipulating individual injection quantities. Initiating combustion during the compression stroke may slew torque generation to the compression stroke.

An aircraft diesel engine may be operated at a minimal fuel rate. Shaft output power of the engine may be reduced by initiating combustion during the compression stroke. Combustion may be initiated during the compression stroke by advancing fuel injection, splitting fuel injection, and/or manipulating individual injection quantities. Initiating combustion during the compression stroke may slew torque generation to the compression stroke.

An aircraft diesel engine may be operated at a minimal fuel rate. Shaft output power of the engine may be reduced by initiating combustion during the compression stroke. Combustion may be initiated during the compression stroke by advancing fuel injection, splitting fuel injection, and/or manipulating individual injection quantities. Initiating combustion during the compression stroke may slew torque generation to the compression stroke.

An aircraft diesel engine may be operated at a minimal fuel rate. Shaft output power of the engine may be reduced by initiating combustion during the compression stroke. Combustion may be initiated during the compression stroke by advancing fuel injection, splitting fuel injection, and/or manipulating individual injection quantities. Initiating combustion during the compression stroke may slew torque generation to the compression stroke.

Methods and systems are provided for catalyst control. In one example, a method may modulate a downstream catalyst by applying a square waveform to an outer feedback control loop. A fuel adjustment is performed in accordance with the square waveform to create an air-fuel ratio oscillation at an upstream catalyst brick and at a downstream catalyst brick.

A system may include at least one processor configured to receive a fuel signal indicative of an amount of fuel supplied to a cylinder of an internal combustion engine, receive an air signal indicative of a quantity of air supplied to the cylinder, and estimate a mean effective pressure in the cylinder based at least in part on the fuel signal and the air signal. The system may estimate an exhaust gas temperature for exhaust gas entering an exhaust manifold associated with the internal combustion engine, generate a rate of temperature change value for the exhaust manifold based at least in part on the exhaust gas temperature, generate an estimated exhaust manifold temperature based at least in part on the rate of temperature change value for the exhaust manifold, and estimate an exhaust gas temperature for exhaust gas exiting the exhaust manifold and entering a turbine of a turbocharger.

A system may include at least one processor configured to receive a fuel signal indicative of an amount of fuel supplied to a cylinder of an internal combustion engine, receive an air signal indicative of a quantity of air supplied to the cylinder, and estimate a mean effective pressure in the cylinder based at least in part on the fuel signal and the air signal. The system may estimate an exhaust gas temperature for exhaust gas entering an exhaust manifold associated with the internal combustion engine, generate a rate of temperature change value for the exhaust manifold based at least in part on the exhaust gas temperature, generate an estimated exhaust manifold temperature based at least in part on the rate of temperature change value for the exhaust manifold, and estimate an exhaust gas temperature for exhaust gas exiting the exhaust manifold and entering a turbine of a turbocharger.