nominal [nominal] a.有名无实的;极微小的;标定的,额 定的 bus[bAs]n总线 innovation[ Inou vel∫onv改进,革新,创新,新发明[技 术,方法] residua[ ri'zidjualla剩余的,残余的
nominal ['nɔminəl] a. 有名无实的；极微小的；标定的，额 定的 bus [bʌs] n.总线 innovation [inou'vei∫ən] v.改进，革新，创新，新发明[技 术，方法] residual [ri'zidjuəl] a.剩余的，残余的
PHRASES AND EXPRESSIONS cam|obe凸轮的凸起部分 valve sten气门杆 variable valve timing(WT)可变气门定时 In essence本质上,实质上 spool valve滑阀 electronic valve control(Evc)电子式气门控制 centralized system集中系统 distributed system分布系统 camless engine无凸轮发动机 smart valve智能气门
cam lobe 凸轮的凸起部分 valve stem 气门杆 variable valve timing（VVT）可变气门定时 in essence 本质上，实质上 spool valve 滑阀 electronic valve control (EVC) 电子式气门控制 centralized system 集中系统 distributed system 分布系统 camless engine 无凸轮发动机 smart valve 智能气门 PHRASES AND EXPRESSIONS
Valve Systems Operation of valve System You have seen that the intake valve must be opened for the intake stroke, both valves must remain closed during the compression and power strokes, and the exhaust valve opens during the exhaust stroke. The designer must design a device to open and close the valves at the proper times The shaft will have an egg-shaped bump called a cam lobe. The cam lobe is machined as an integral part of the shaft. this shaft is called a camshaft The distance the valve will be raised, how long it will stay open, and how fast it opens and closes can all be controlled by the height and shape of the lobe [11 As you will see later, it is impractical to have the cam lobe contact the end of the valve stem itself. You have placed the camshaft some distance above the end of the valve stem
Valve Systems Operation of Valve System You have seen that the intake valve must be opened for the intake stroke, both valves must remain closed during the compression and power strokes, and the exhaust valve opens during the exhaust stroke. The designer must design a device to open and close the valves at the proper times. The shaft will have an egg-shaped bump called a cam lobe. The cam lobe is machined as an integral part of the shaft. This shaft is called a camshaft. The distance the valve will be raised, how long it will stay open, and how fast it opens and closes can all be controlled by the height and shape of the lobe [1]. As you will see later, it is impractical to have the cam lobe contact the end of the valve stem itself. You have placed the camshaft some distance above the end of the valve stem
When the camshaft is turn the lobes will not even touch the valve stem. the lifter is installed between the cam lobe and the valve stem. The upper end rides on the lobe and the lower end almost touches the valve stem the lifter slides up and down in a hole bored in the head metal that separates the valve stem from the camshaft [2] You have developed a method of opening and closing the valves. The next problem is how and at what speed to turn the camshafts. each valve must be open for one stroke. The intake valve is open during the intake stroke and remains closed during the compression, power, and exhaust strokes This would indicate that the cam lobe must turn fast enough to raise the valve every fourth stroke You can see that it takes one complete revolution of the cam lobe for every four strokes of the piston
When the camshaft is turn, the lobes will not even touch the valve stem. The lifter is installed between the cam lobe and the valve stem. The upper end rides on the lobe and the lower end almost touches the valve stem. The lifter slides up and down in a hole bored in the head metal that separates the valve stem from the camshaft [2]. You have developed a method of opening and closing the valves. The next problem is how and at what speed to turn the camshafts. Each valve must be open for one stroke. The intake valve is open during the intake stroke and remains closed during the compression, power, and exhaust strokes. This would indicate that the cam lobe must turn fast enough to raise the valve every fourth stroke. You can see that it takes one complete revolution of the cam lobe for every four strokes of the piston