Abstract: Reducing engagement noise in a chain drive or belt drive for an internal combustion engine having a crankshaft having a driving sprocket and at least one shaft having a first driven sprocket and a second driven sprocket, where the driving sprocket and at least one of the first driven sprocket and the second driven sprocket contain a pattern of pitch radii such that the radial variation of the pitch radii excite tensions at non-prevalent orders in a drive system of the internal combustion engine. The non-prevalent engine cycle orders excited by each of the driving sprocket, the first driven sprocket and the second driven sprocket are different.

Abstract: A tensioner for tensioning a chain span which uses two pistons. The movement of the two pistons may be coupled together. The first piston provides damping to the chain span and a second piston provides variable, dominant and automatically adjusting spring force to the chain span. The tensioner automatically adjusts the mean tension force to keep the chain tension as low as possible without sacrificing chain control, significantly improving drive efficiency at new chain conditions and conditions with dynamic loads.

Abstract: A tensioner which adjusts the mean tensioner force to keep the chain tension as low as possible without sacrificing chain control, significantly improving drive efficiency as the chain wears and is subject to low dynamic loads.

Abstract: A non-prevalent order random sprocket for an internal combustion engine comprising a pattern of pitch radii, such that the radial variation of the pitch radii excite tensions at non-prevalent orders in a drive system of the internal combustion engine.

Abstract: A pressure regulator is in fluid communication with a supply inlet of a hydraulic tensioner to actively control fluid to the inlet of the hydraulic tensioner. By actively controlling the pressure regulator based on engine conditions and thus the oil pressure being fed to the hydraulic tensioner, the oil pressure to the hydraulic tensioner may be reduced at low engine speeds, increasing the efficiency of the timing system, or allowing full oil pressure at high engine speeds and low engine temperature.

Abstract: A tensioner for tensioning a chain span which uses two pistons. The movement of the two pistons may be coupled together. The first piston provides damping to the chain span and a second piston provides variable, dominant and automatically adjusting spring force to the chain span. The tensioner automatically adjusts the mean tension force to keep the chain tension as low as possible without sacrificing chain control, significantly improving drive efficiency at new chain conditions and conditions with dynamic loads.

Abstract: A tensioner which adjusts the mean tensioner force to keep the chain tension as low as possible without sacrificing chain control, significantly improving drive efficiency as the chain wears and is subject to low dynamic loads.

Abstract: A tensioner for tensioning a chain span which uses two pistons. The movement of the two pistons may be coupled together. The first piston provides damping to the chain span and a second piston provides variable, dominant and automatically adjusting spring force to the chain span. The tensioner automatically adjusts the mean tension force to keep the chain tension as low as possible without sacrificing chain control, significantly improving drive efficiency at new chain conditions and conditions with dynamic loads.

Abstract: A tensioner for tensioning a chain span which uses two pistons. The movement of the two pistons may be coupled together. The first piston provides damping to the chain span and a second piston provides variable, dominant and automatically adjusting spring force to the chain span. The tensioner automatically adjusts the mean tension force to keep the chain tension as low as possible without sacrificing chain control, significantly improving drive efficiency at new chain conditions and conditions with dynamic loads.

Abstract: In order to prevent noise, a ratchet clip and grooves for the ratchet clip to engage are added to the second piston, such that the second piston cannot hit the bottom of the second bore housing. The second piston is prevented from hitting the bottom of the second bore housing by the ratchet clip engaging the ratchet grooves on the outer circumference of the second piston.

Abstract: A tensioner which adjusts the mean tensioner force to keep the chain tension as low as possible without sacrificing chain control, significantly improving drive efficiency as the chain wears and is subject to low dynamic loads.

Abstract: A non-prevalent order random sprocket for an internal combustion engine comprising a pattern of pitch radii, such that the radial variation of the pitch radii excite tensions at non-prevalent orders in a drive system of the internal combustion engine.

Abstract: A tensioner which adjusts the mean tensioner force to keep the chain tension as low as possible without sacrificing chain control, significantly improving drive efficiency as the chain wears and is subject to low dynamic loads.

Abstract: A tensioner for tensioning a chain or belt span which uses two pistons. The movement of the two pistons may be coupled together. The first piston provides damping to the chain span and a second piston provides variable, dominant and automatically adjusting spring force to the chain span. The tensioner automatically adjusts the mean tension force to keep the chain or belt tension as low as possible without sacrificing chain or belt control, significantly improving drive efficiency at new chain or belt conditions and conditions with dynamic loads.

Abstract: A tensioner which adjusts the mean tensioner force to keep the chain tension as low as possible without sacrificing chain control, significantly improving drive efficiency as the chain wears and is subject to low dynamic loads.

Abstract: A pressure regulator is in fluid communication with a supply inlet of a hydraulic tensioner to actively control fluid to the inlet of the hydraulic tensioner. By actively controlling the pressure regulator based on engine conditions and thus the oil pressure being fed to the hydraulic tensioner, the oil pressure to the hydraulic tensioner may be reduced at low engine speeds, increasing the efficiency of the timing system, or allowing full oil pressure at high engine speeds and low engine temperature.

Abstract: A tensioner which adjusts the mean tensioner force to keep the chain tension as low as possible without sacrificing chain control, significantly improving drive efficiency as the chain wears and is subject to low dynamic loads.

Abstract: A tensioner for tensioning a chain span which uses two pistons. The movement of the two pistons may be coupled together. The first piston provides damping to the chain span and a second piston provides variable, dominant and automatically adjusting spring force to the chain span. The tensioner automatically adjusts the mean tension force to keep the chain tension as low as possible without sacrificing chain control, significantly improving drive efficiency at new chain conditions and conditions with dynamic loads.

Abstract: A tensioner for tensioning a chain span which uses two pistons. The movement of the two pistons may be coupled together. The first piston provides damping to the chain span and a second piston provides variable, dominant and automatically adjusting spring force to the chain span. The tensioner automatically adjusts the mean tension force to keep the chain tension as low as possible without sacrificing chain control, significantly improving drive efficiency at new chain conditions and conditions with dynamic loads.

Abstract: A tensioner for tensioning a chain span which uses two pistons. The movement of the two pistons may be coupled together. The first piston provides damping to the chain span and a second piston provides variable, dominant and automatically adjusting spring force to the chain span. The tensioner automatically adjusts the mean tension force to keep the chain tension as low as possible without sacrificing chain control, significantly improving drive efficiency at new chain conditions and conditions with dynamic loads.