An abnormality determination device is applied to an electrostatic capacitance type fuel property sensor that has a sensing section that senses an electrostatic capacitance of a fuel to be detected. The abnormality determination device of the fuel property sensor acquires a first output that is an output when a predetermined voltage is applied to the sensing section and a second output that is an output when a voltage is not applied to the sensing section. The acquired first output and second output are compared and whether or not the fuel property sensor is abnormal is determined.

Methods and systems are provided for estimating fuel volatility. During a vehicle-off condition following a refueling event, fuel volatility may be estimated by operating a fuel pump of a fuel system immediately after the refueling event while a fuel tank temperature is stable. Based on estimated fuel volatility, fuel injection amount and leak test thresholds may be adjusted.

Methods and systems are provided for a multi-fuel engine. In one example, a method includes adjusting a substitution ratio based on an intake manifold temperature. The method further including adjusting the intake manifold temperature to increase the substitution ratio.

Provided herein are processes and microorganisms which utilize both protein hydrolysates and carbohydrates from biomass feedstocks to produce renewable hydrocarbon compositions. Advantages of the disclosed methods may be recognized in fuel blends comprising such hydrocarbon compositions.

A method for starting a direct-injection internal combustion engine of a vehicle includes: rotating the high-pressure injection pump by a starter; measuring fuel pressure delivered by the pump, taken at two successive compression top dead centers of the pump operating in maximum output mode; establishing the pressure gradient of the fuel, on an angular reference system, based on the two successive pressure measurements; comparing the established gradient with a predefined bijective table that respectively matches a plurality of quantities of fuel to be injected and a plurality of pressure gradients; and adapting the quantity of fuel injected during the starting phase before the engine reaches steady operating speed, depending on the result of the comparison, in order to inject a quantity of fuel that corresponds, in the predefined bijective table, to the established pressure gradient, upon authorization of the first injection given by the engine control unit.

In a flexible-fuel engine capable of using fuel containing alcohol as fuel to be combusted in a cylinder, the geometric compression ratio is set to 12 or more, the engine is started by using fuel containing alcohol, an intake valve closing timing at an engine start time is set to an advance angle side than a first reference timing being a timing corresponding to a most retarded angle position out of intake valve closing timings capable of starting the engine in combusting fuel of alcohol 100% in the cylinder at a first intake temperature, and is set to a timing on a retarded angle side than a second reference timing being a timing corresponding to a most advanced angle position out of intake valve closing timings capable of avoiding pre-ignition in combusting fuel of gasoline 100% at an engine start time at a second intake temperature.

Methods and systems are provided for improving engine knock control by accounting for a drop in charge cooling efficiency of a knock control fluid at higher temperatures. In response to the prediction of an elevated temperature of a knock control fluid at a time of release from a direct injector, a pulse width of the injection is adjusted. Any knock relief deficits are compensated for using alternate engine adjustments, such as boost or spark timing adjustments.

A fuel type estimation system configured to estimate a type variable related to a type of fuel in an engine system including an engine and a fuel supply apparatus includes a storage device and an execution device. The storage device is configured to store a mapping that uses, as inputs, input variables including an engine variable related to a condition of the engine and outputs the type variable. The execution device is configured to acquire the input variables, and estimate the type variable by applying the acquired input variables to the mapping.

Methods and systems are provided for adjusting spark and/or fuel injection to a cylinder based on late combustion, partial burn, or misfire in a neighboring cylinder. In one example, a method may include deactivating spark and fuel injection to a second cylinder receiving exhaust residuals from combustion in a first cylinder, the first cylinder experiencing a misfire or late combustion event. Mitigating actions are performed in the second cylinder before the occurrence of a pre-ignition event.

A method may comprise: positioning a pressure control valve (PCV) at an outlet of a fuel rail; positioning a volume control valve (VCV) at an inlet of a high pressure pump; and in response to an exhaust particulate matter (PM) level deviating from a target PM level, adjusting a fuel ratio of a first fuel and a second fuel delivered to an engine, and opening one of the PCV and the VCV. In this way, the fuel oxygen content may be adjusted to maintain a PM at or below a target level without a DPF over a broad range of engine designs and operating conditions, while maintaining fuel economy.