Abstract: A high pressure pump for decreasing an initial axial force of a clamping bolt and preventing distortion of a sealing surface and a cylinder form. The high pressure pump has an intermediate member including a cylinder body (4). The cylinder body has a pressurizing chamber (14) communicated with a cylinder (4a) accommodating a plunger (12). Fluid in the pressurizing chamber is pressurized by reciprocating the plunger. The intermediate member is arranged between a cover (6) and a flange (8) and clamped by a clamping bolt (40). The clamping bolt has an exposed area (40a) at its axially central area where the entire periphery of the clamping bolt is exposed from the cover and the flange. One or both of the cover and the flange clamp the intermediate member with a flexing elastic force.

Abstract: The amount of fuel ejected from a high-pressure fuel pump that ejects fuel toward a delivery pipe is adjusted by controlling the valve closure start timing of an electromagnetic spill valve. In this manner, the fuel pressure in the delivery pipe is controlled. The duty ratio DT used for controlling the valve closure start timing of the electromagnetic spill valve is calculated based on a valve closure start timing that provides a maximum amount of fuel ejection. The actual fuel ejection characteristic of a high-pressure fuel pump may deviate from a designed state due to individual differences of the pump. However, the valve closure start timing of the electromagnetic spill valve that provides the maximum amount of fuel ejection in accordance with the actual fuel ejection characteristic is learned as a maximum ejection timing. Based on the maximum ejection timing, the duty ratio DT is calculated.

Abstract: The polyamic acid of the invention can be obtained by the reaction of an acid anhydride component comprising pyromellitic anhydride and 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane with 2,2′-di-substituted-4,4′-diaminobiphenyls as a first aromatic diamine and any aromatic diamine component, as a second aromatic diamine, of 2,2-bis(4-aminophenoxyphenyl)propanes, 1,1-bis(4-(4-aminophenoxy)-3-t-butyl-6-methylphenyl)butane, 2,2-bis(3-amino-4-methylphenyl)hexafluoropropane and &agr;,&agr;′-bis(4-aminophenyl)diisopropylbenzenes in an organic solvent. The polyimide resin of the invention can be obtained by heating such a polyamic acid solution. In the production of a circuit board, by using a photosensitive polyamic acid having a sensitizer incorporated in such a polyamic acid solution, a patterned polyimide resin layer can be provided as an insulation layer on a metal foil.

Abstract: A direct injection type internal combustion engine control apparatus is capable of increasing the frequency of performing the compression-stroke fuel injection following an automatic start of the engine by maintaining a sufficient fuel pressure for the compression-stroke injection even after the engine has been stopped by an automatic stop function. When an immediately-before-automatic-stop flag is “ON”, the control apparatus sets the control duty of an electromagnetic spill valve to 100 (%) to raise the fuel pressure immediately before the automatic stop. As a result, after the engine stops, the fuel pressure starts to decrease from a high pressure, so that there will be a long time before the fuel pressure decreases to a level that makes it impossible to perform appropriate fuel injection into the combustion chamber during the compression stroke.

Abstract: In a high-pressure fuel pump of a fuel supplying apparatus, the amount of movement of a plunger (cam speed) occurring during a unit-angle rotation of a cam changes in accordance with the phase of the cam. The amount of fuel delivered from the high-pressure fuel pump is controlled by changing the start timing of closure of an electromagnetic spill valve. However, the amount of fuel delivered is greatly affected by the cam speed at the start of closure of the spill valve. Therefore, for example, a cam profile of the cam is set such that the closure start timing of the electromagnetic spill valve that provides a maximum amount of fuel that needs to be delivered for fuel injection is placed within a predetermined cam angle range in which the change in the cam speed with respect to changes in phase of the cam is constant.

Abstract: The polyamic acid of the invention can be obtained by the reaction of an acid anhydride component comprising pyromellitic anhydride and 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane with 2,2′-di-substituted-4,4′-diaminobiphenyls as a first aromatic diamine and any aromatic diamine component, as a second aromatic diamine, of 2,2-bis(4-aminophenoxyphenyl)propanes, 1,1-bis(4-(4-aminophenoxy)-3-t-butyl-6-methylphenyl)butane, 2,2-bis(3-amino-4-methylphenyl)hexafluoropropane and &agr;,&agr;′-bis(4-aminophenyl)diisopropylbenzenes in an organic solvent. The polyimide resin of the invention can be obtained by heating such a polyamic acid solution. In the production of a circuit board, by using a photosensitive polyamic acid having a sensitizer incorporated in such a polyamic acid solution, a patterned polyimide resin layer can be provided as an insulation layer on a metal foil.

Abstract: A direct injection type internal combustion engine control apparatus is capable of increasing the frequency of performing the compression-stroke fuel injection following an automatic start of the engine by maintaining a sufficient fuel pressure for the compression-stroke injection even after the engine has been stopped by an automatic stop function. When an immediately-before-automatic-stop flag is “ON”, the control apparatus sets the control duty of an electromagnetic spill valve to 100(%) to raise the fuel pressure immediately before the automatic stop. As a result, after the engine stops, the fuel pressure starts to decrease from a high pressure, so that there will be a long time before the fuel pressure decreases to a level that makes it impossible to perform appropriate fuel injection into the combustion chamber during the compression stroke.

Abstract: During the idling state, the number of times of injecting fuel per performance of the fuel delivery from a high-pressure fuel pump is decreased or increased. If the number of times of injecting fuel per performance of the fuel delivery is decreased, the amount of fuel that needs to be delivered by one performance of the fuel delivery is reduced, so that the timing of starting to close an electromagnetic spill valve can be delayed. Therefore, the lift of a plunger for 1° rotation of a cam (i.e., cam speed) at the time of closure of the electromagnetic spill valve decreases, so that the force applied from fuel to the electromagnetic spill valve in the valve closing direction decreases.

Abstract: The amount of fuel ejected from a high-pressure fuel pump that ejects fuel toward a delivery pipe is adjusted by controlling the valve closure start timing of an electromagnetic spill valve. In this manner, the fuel pressure in the delivery pipe is controlled. The duty ratio DT used for controlling the valve closure start timing of the electromagnetic spill valve is calculated based on a valve closure start timing that provides a maximum amount of fuel ejection. The actual fuel ejection characteristic of a high-pressure fuel pump may deviate from a designed state due to individual differences of the pump. However, the valve closure start timing of the electromagnetic spill valve that provides the maximum amount of fuel ejection in accordance with the actual fuel ejection characteristic is learned as a maximum ejection timing. Based on the maximum ejection timing, the duty ratio DT is calculated.

Abstract: A valve train for driving an engine valve in an internal combustion engine. A pump having a pressure chamber compresses and supplies fuel to the engine. An intake camshaft has valve cams for selectively opening and closing the intake valves and a pump cam for driving the pump. The intake camshaft has a torque fluctuation as a result of driving the intake valves and as a result of compressing fuel by the pump. A timing belt connects a crankshaft to the intake camshaft. The pump cam has a phase with respect to the intake camshaft to reduce a composite of the torque fluctuation (the net torque fluctuation) generated in the intake camshaft by the intake valves and the pump. This improves the life of the timing belt.