TH88367A - Controller for single-cylinder four-stroke engines - Google Patents

Abstract

In a single-cylinder (10) four-stroke DC60 engine, the rotational speed is not uniform as the crankshaft (19) is rotated one revolution. The time (T30) required to rotate the crankshaft (19) to the specified crank angle will be different for each stroke, in particular. The tendency of the time (T30) required for rotation will differ for each stroke. The time (T30) for crank angle numbers Cn=8, 9 is obtained (Steps S104, S107), and the time difference (deltaT30) between the different time intervals (T30) required for rotation is calculated (Step S109). In the next step, the time difference (deltaT30) is compared to the previously determined timing values K1 and K2 (Steps S110, 113) to determine the timing of the current stroke (Steps S111, S114). In a single-cylinder four-stroke engine (10), the rotational speed is not uniform as the crankshaft (19) is rotated one revolution. The time (T30) required to rotate the crankshaft (19) to a specified crank angle will differ for each stroke, in particular. The tendency for the change in time (T30) required for each rotation will differ for each stroke. The time (T30) for crank angles Cn=8, 9 is obtained (Steps S104, S107), and the time difference ((formula)T30) between the different time intervals (T30) required for each rotation is calculated (Step S109). Subsequently, the time difference ((formula)T30) is compared to the previously determined timing values K1 and K2 (Steps S110, S113) to determine the current stroke (Steps S111, S114).

Claims (4)

1. A controller for a single-cylinder four-stroke engine (10) that rotates the crankshaft (19) by moving the piston back and forth (17) in the cylinder to increase and decrease the cylinder volume (200). The controller consists of a crank angle sensor (22) that outputs a rotation detection signal each time the crankshaft (19) is rotated to a predetermined angle; a computational trajectory (30) for calculating the time required for the crankshaft (19) to be a predetermined crank angle at a reference angle position on the crankshaft based on the signal output from the crank angle sensor (22), where the reference angle position is the angle position within the time interval during which the cylinder volume (200) is increased by the piston; and a decision trajectory (30) for making a decision on the timing based on two consecutive time intervals required for the rotation, which are calculated by the computational trajectory within the time interval during which the cylinder volume (200) is increased. 2. The controller for a single-cylinder four-stroke engine under claim 1, where the determination path is determined, compares the difference between two consecutive time intervals required for rotation, which is calculated by the computational path, with a previously determined determination reference value to determine the timing of the current stroke. 3. A controller for a single-cylinder four-stroke engine under claim 1, where, when the engine rotational speed is outside the predetermined range from the predetermined reference rotational speed, no timing decision is made when the engine is started. 4. The controller for a single-cylinder four-stroke engine under claim 1, where the determination path is determined, sets the determined result obtained each time the crankshaft is rotated one revolution as a transient result and sets the determined result when a specified number of transient results are obtained consecutively as normal.