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.

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.

The invention involves a system and method for providing a liquid fuel or a liquid and gaseous fuel to a diesel or Otto cycle engine for operation of the engine. The system includes a primary electronic control module (ECM), which monitors engine sensors and contains a first three-dimensional fuel map for the liquid fuel. A second ECM is connected for bi-directional transfer of information to the first ECM, the second ECM contains a second three-dimensional fuel map for delivery of the gaseous fuel through a secondary gaseous fuel injection assembly. The bi-directional communication between the two ECMs while monitoring the engine sensors allows both ECMs to “learn” an efficient fuel map for delivery of both fuels in the same cycle for improved efficiency, reduction in slip and lower emissions.

A fuel supply apparatus includes a material fuel tank, a separator, a condenser, a first fuel tank, and a first storage device. The material fuel tank is to store a material fuel. The separator is to separate the material fuel supplied from the material fuel tank into a first fuel and a second fuel. The condenser is to condense the first fuel supplied from the separator through a primary-order recovery passage. The first fuel tank is to store the first fuel supplied from the condenser through a secondary-order recovery passage. The first storage device is provided in the secondary-order recovery passage to temporarily store the first fuel supplied from the condenser.

A system for measuring quality of fuel in an engine is disclosed. The system includes a fuel quality measuring unit and a controller in communication with the fuel quality measuring unit. The fuel quality measuring unit includes a first valve, a second valve, and a quality measurement sensor disposed between the first valve and the second valve. The controller is configured to determine whether the engine is running in a steady state condition, and identify a measurement window based on a pressure of the fuel at an inlet, an Intake Manifold Pressure (IMP), and the steady state condition. The controller is configured to control an opening and a closing of the first valve, the second valve, and a fuel metering valve during the measurement window. The controller is configured to determine the quality of the fuel captured between the first valve and the second valve by the quality measurement sensor.

Spark ignition engine operation at higher RPM so as to reduce alcohol requirements in high efficiency alcohol enhanced gasoline engines is disclosed. Control of engine upspeeding (use of a higher ratio of engine RPM to wheel RPM) so as to achieve an alcohol reduction objective while limiting any decrease in efficiency is described. High RPM alcohol enhanced gasoline engine operation in plug-in series hybrid powertrains for heavy duty trucks and other vehicles is also described.

Spark ignition engine operation at higher RPM so as to reduce alcohol requirements in high efficiency alcohol enhanced gasoline engines is disclosed. Control of engine upspeeding (use of a higher ratio of engine RPM to wheel RPM) so as to achieve an alcohol reduction objective while limiting any decrease in efficiency is described. High RPM alcohol enhanced gasoline engine operation in plug-in series hybrid powertrains for heavy duty trucks and other vehicles is also described.

Various methods and systems are provided for a multi-fuel capable engine. In one example, a system comprises an engine having at least one cylinder controlled via an intake valve, a first fuel system to deliver liquid fuel and a second fuel system to deliver gaseous fuel to the at least one cylinder, a variable valve timing actuation system to adjust one or more of an opening or a closing timing of the intake valve, and a controller. The controller is configured to, during a liquid fuel only mode, adjust the variable valve timing actuation system to close the intake valve at a first timing based at least on engine load, and during a multi-fuel mode, adjust the variable valve timing actuation system to close the intake valve at a second timing.

In a multi-fuel system for diesel engines, natural gas is mixed with diesel fuel and conditioned in a mixing chamber before being injected into the mixing chamber of the engine. Filtered blow-by gas may also be introduced into the combustion chamber. A computerized controller is used to determine and control the proportion of diesel fuel, natural gas fuel, the mixing and conditioning of these fuels, and the supply of filtered blow-by gas.