Electrohydraulic device for closed-loop driving the control jack of a variable compression ratio engine

摘要

An electrohydraulic device for controlling the compression ratio of a variable compression-ratio engine, includes at least one dual-flow electrovalve (81) with no check valve and capable of opening and closing at least one hydraulic fluid duct (83) between the upper chamber (121) and the lower chamber (122) of a control jack (8), at least one position sensor (82) of a control rack (7), an angular position sensor (88) of the crankshaft (9) of the engine for adjusting the compression ratio, and at least one calculator (84).

主权项

1. An electrohydraulic device controlling a compression ratio of a variable compression ratio engine, comprising:
a computer (84); a transmission member (3) in a bottom portion of a piston (2), the transmission member (3) secured to the piston and interacting with i) a rolling guidance device (4) and ii) a gearwheel (5) interacting with a connecting rod (6) connected to a crankshaft (9) in order to transmit movement between the piston (2) and the crankshaft (9); a control rack (7), the gearwheel (5) interacting opposite to the transmission member (3) with the control rack (7); a control device (12) comprised of a control jack (8) controlling a vertical position of the control rack (7), the control jack (8) comprising, above and below a jack piston (13), a top chamber (121) and a bottom chamber (122), a duct (83) of hydraulic fluid located between the top and chamber bottom chambers; a hydraulic unit supplying hydraulic fluid under pressure to the top and bottom chambers via two booster check valves (188, 185) opening respectively into each of the top and bottom chambers to allow the hydraulic fluid to enter the top and bottom chambers while preventing the hydraulic fluid from leaving the top and bottom chambers; an control jack position sensor (82) located at the control jack (8) and connected to the computer (84) and arranged to determine the vertical position of the control rack (7); a two-way electrovalve (81) configured to open and close the duct (83) connecting the top chamber and bottom chambers of the control jack (8); and an engine crankshaft angular position sensor (88) located adjacent the engine crankshaft (9), wherein, the two-way electrovalve (81) interacts with the control jack position sensor (82), the engine crankshaft angular position sensor (88), and the computer (84) to regulate the compression ratio so that control jack vertical position and engine crankshaft angular position regulate the compression ratio, the two-way electrovalve (81) comprises two parallel channels, a first of the two channels shutoff by a device with a relatively large flow-rate shutoff and a relatively slow response, and a second of the two channels shutoff by another device for a relatively low flow-rate shutoff and a relatively fast response.