Additional approaches for the reduction of particulate emissions in gasoline engines using optimized port+direct injection are described. These embodiments include control of the amount of directly injected fuel so as to avoid a threshold increase in particulates due to piston wetting and reduction of cold start emissions by use of air preheating using variable valve timing.

An HT cooling system cools at least a cylinder block with HT cooling water. An LT cooling system cools an intake port with LT cooling water that is at a lower temperature than the HT cooling water. A controller performs an ignition retard control that involves correcting the ignition timing based on the result of detection of a knock by a knock sensor, and a cooling enhancement control that involves enhancing cooling by the LT cooling system in the case where a knock is detected compared with the case where no knock is detected. The way of cooling by the HT cooling system is unchanged whether a knock is detected.

An HT cooling system cools at least a cylinder block with HT cooling water. An LT cooling system cools an intake port with LT cooling water that is at a lower temperature than the HT cooling water. A controller performs an ignition retard control that involves correcting the ignition timing based on the result of detection of a knock by a knock sensor, and a cooling enhancement control that involves enhancing cooling by the LT cooling system in the case where a knock is detected compared with the case where no knock is detected. The way of cooling by the HT cooling system is unchanged whether a knock is detected.

An electronic engine timing system that includes at least (1) an engine position sensor that includes a diametric magnet and two or more hall effect sensors configured and positioned to sense diametric magnet position, (2) sensor data receiving circuitry configured for receiving sensory input, including at least input from the engine position sensor; and (3) control circuitry configured to control firing of one or more cylinders of the engine at least in part by calculating one or more timing advance positions for one or more cylinders of the engine and by causing the one or more cylinders to fire according to the one or more calculated timing advance positions, the control circuitry further configured to calculate the one or more timing advance positions for the one or more cylinders separately from one another based at least in part on input from the engine position sensor.

To provide a controller and a control method, for an internal combustion engine, that can detect occurrence of knocking appropriately, even though the frequency distribution of the knock signal is distorted according to the occurrence state of knocking. The controller for the internal combustion engine calculates the background level by processing a low pass filter to the knock signal; and performs a low side frequency increase which makes a low side frequency, which is a cutoff frequency of the low pass filter in the case where the knock signal is smaller than an output value of the low pass filter, higher than a high side frequency, which is a cutoff frequency of the low pass filter in the case where the knock signal is larger than the output value of the low pass filter.

To provide a controller and a control method, for an internal combustion engine, that can detect occurrence of knocking appropriately, even though the frequency distribution of the knock signal is distorted according to the occurrence state of knocking. The controller for the internal combustion engine calculates the background level by processing a low pass filter to the knock signal; and performs a low side frequency increase which makes a low side frequency, which is a cutoff frequency of the low pass filter in the case where the knock signal is smaller than an output value of the low pass filter, higher than a high side frequency, which is a cutoff frequency of the low pass filter in the case where the knock signal is larger than the output value of the low pass filter.

An internal combustion engine knock determining device includes a vibration detector that produces a signal corresponding to engine vibration, an intensity computing unit that retrieves vibrational components in a plurality of frequency regions in which vibration intensity peaks are located when knock occurs, a background-noise computing unit that calculates background noise caused by factors other than knock, a frequency computing unit that determines specific frequency regions from which to determine whether knock is occurring by excluding certain frequency regions designated as frequency regions requiring exclusion due to the intensity of false-detection causing noise as a proportion of the background noise in the certain regions, and a knock determining unit that determines the occurrence of knock based on the vibration intensity in the specific frequency regions obtained by excluding the frequency regions requiring exclusion, wherein the number of specific frequency regions is increased to improve the accuracy of knock detection.

An internal combustion engine knock determining device includes a vibration detector that produces a signal corresponding to engine vibration, an intensity computing unit that retrieves vibrational components in a plurality of frequency regions in which vibration intensity peaks are located when knock occurs, a background-noise computing unit that calculates background noise caused by factors other than knock, a frequency computing unit that determines specific frequency regions from which to determine whether knock is occurring by excluding certain frequency regions designated as frequency regions requiring exclusion due to the intensity of false-detection causing noise as a proportion of the background noise in the certain regions, and a knock determining unit that determines the occurrence of knock based on the vibration intensity in the specific frequency regions obtained by excluding the frequency regions requiring exclusion, wherein the number of specific frequency regions is increased to improve the accuracy of knock detection.

When an operating condition including load and speed of an internal combustion engine is in a prescribed low-speed high-load region, i.e., an energy suppression region, having a possibility causing pre-ignition, energization time TDWLMIN for the energy suppression region is selected as a primary coil energization time. In other normal regions, normal energization time TDWL is selected. Normal energization time TDWL has a characteristic such that the normal energization time shortens, as the engine speed increases. In a low speed region, a given energization time that can fulfill a discharge energy required in a high exhaust gas recirculation region is provided. Energization time TDWLMIN for the energy suppression region is constant regardless of engine speeds and relatively short, and is set to a level such that a coil generated maximum voltage does not exceed a withstand voltage of a spark plug even when no-discharge occurs due to pre-ignition.

When an operating condition including load and speed of an internal combustion engine is in a prescribed low-speed high-load region, i.e., an energy suppression region, having a possibility causing pre-ignition, energization time TDWLMIN for the energy suppression region is selected as a primary coil energization time. In other normal regions, normal energization time TDWL is selected. Normal energization time TDWL has a characteristic such that the normal energization time shortens, as the engine speed increases. In a low speed region, a given energization time that can fulfill a discharge energy required in a high exhaust gas recirculation region is provided. Energization time TDWLMIN for the energy suppression region is constant regardless of engine speeds and relatively short, and is set to a level such that a coil generated maximum voltage does not exceed a withstand voltage of a spark plug even when no-discharge occurs due to pre-ignition.