In an alcohol concentration estimation apparatus for an engine, a first crank angular speed (ω1) within a first predetermined interval overlapping with the compression top dead center is calculated, and a first variation amount (Δω1) is calculated by subtracting ω1 from an average engine speed. A second crank angular speed (ω2) within a second predetermined interval overlapping with the combustion bottom dead center is calculated, and a second variation amount (Δω2) is calculated by subtracting ω1 from ω2. In a relationship between air fuel ratio A/F and an indicated mean effective pressure (IMEP)/charging efficiency (ηc) of the engine when the engine is operated with a predetermined fuel injection map indicating a relationship between A/F and IMEP/ηc for each desired alcohol concentration, IMEP/ηc is substituted by Δω2/Δω1 ratio to estimate an alcohol concentration in fuel. The alcohol concentration estimation apparatus eliminates requirement of sensors for detecting an intake air mass.

Fuel management system for enhanced operation of a spark ignition gasoline engine. Injectors inject an anti-knock agent such as ethanol directly into a cylinder. It is preferred that the direct injection occur after the inlet valve is closed. It is also preferred that stoichiometric operation with a three way catalyst be used to minimize emissions. In addition, it is also preferred that the anti-knock agents have a heat of vaporization per unit of combustion energy that is at least three times that of gasoline.

A control device of the present invention is applied to an engine provided with a fuel injection valve which directly injects fuel into a combustion chamber. The control device includes a pre-ignition prediction unit which predicts occurrence of pre-ignition when the engine is started; and an injection control unit which causes fuel to be injected in an expansion stroke from the fuel injection valve when occurrence of pre-ignition is predicted by the pre-ignition prediction unit. Thus, it is possible to prevent pre-ignition without lowering the effective compression ratio.

Methods and systems are provided for reducing hot fuel vapor formation in a port injection fuel rail. In one example, a method may include operating a dual fuel injection system with at least a calibrated minimum amount of port fuel injection over a wide range of engine operating conditions, even as conditions change. A direct fuel injection amount is adjusted in accordance.

Methods and systems are provided for synergizing the benefits of a multi-fuel engine in a hybrid vehicle system. During engine operation, in response to a change in driver demand, the controller may opt to switch fuels or maintain a current fuel while using stored power assist. The selection may be based on the combination of fuel and stored power offset that provides the highest engine efficiency at the lowest fuel cost.

An objective of the present invention is to stabilize the fuel injection amount for each cylinder and to execute fuel injection control accurately in a single-pressure-feed dual-injection type alcohol fuel injection system. An engine includes two injection valves and and a single-pressure-feed dual-injection type fuel supply system. The fuel supply system is configured such that fuel is injected sequentially in two cylinders during the pressure-feed-interval period from the execution of one fuel pressure-feed operation to the execution of the next fuel pressure-feed operation. If the alcohol concentration in the fuel is higher than a predetermined determination value γ at a startup operation time, an ECU executes only a cylinder injection for the first of the two cylinders described above, and executes both an intake passage injection and a cylinder injection for the second cylinder. Thus, even if the fuel pressure decreases due to the fuel injection for the first cylinder, the required fuel injection amount can be reserved for the second cylinder.

A storage device is configured to store a first mapping that receives, as an input, a first input variable including a cam phase variable on present and past phases of a cam, and output a pulsating variable on a pulsating component. The execution device is configured to acquire the first input variable and estimate the pulsating variable by applying the acquired first input variable to the first mapping. Therefore, it is possible to estimate the pulsating variable without providing a low-pressure fuel pressure sensor by estimating a fuel pressure variable by applying the first input variable to the first mapping.

Methods and systems are provided herein for increasing an efficiency of an evaporative emissions system of a vehicle by adjusting a purge flow in response to a predicted vapor slug. In one example, a method for an engine of a vehicle includes, upon approaching a location of a predicted vapor slug, ramping down a purge flow rate from a fuel vapor canister to an engine intake, the location of the predicted vapor slug inferred based on communication of the vehicle with one or more other vehicles and/or a network cloud.

A fuel pressure estimation system estimates a fuel pressure variable on a fuel pressure in a supply pipe for an engine apparatus including an engine having a fuel injection valve, and a fuel supply device having a fuel pump that supplies the fuel in a fuel tank to the supply pipe, and includes a storage device and an execution device. The storage device stores a first mapping that receives, as an input, first input variables including a pump variable, a consumption flow rate variable on a consumption flow rate of the fuel, and a property variable on a property of the fuel, and outputs the fuel pressure variable. The execution device acquires the first input variables and estimates the fuel pressure variable by applying the first input variables to the first mapping.

In a fuel pressure control device for an internal combustion engine of the invention, a first map (FIG. 4A) for defining a first target fuel pressure for normal time and a second map (FIG. 5A) for defining a second target fuel pressure for suppressing noise and vibration smaller than the first target fuel pressure are stored. When an acquired fuel temperature is higher than a predetermined temperature, the first target fuel pressure defined in the first map is set as a target fuel pressure (steps 1 to 3), and when the fuel temperature is equal to or lower than the predetermined temperature, the second target fuel pressure defined in the second map is set as the target fuel pressure (steps 1, 5, and 6). The fuel pressure is controlled based on the set target fuel pressure (step 7).