Concept explainers
- Explain staged and continuously variable value timing systems.
The explanation of staged and continuously variable valve timing systems.
Explanation of Solution
Staged variable valve timing:
Staged valve timing consists of a central camshaft, where the lobes push against the wall to open when the camshaft is rotated. Crankshaft provides input to drive cam. Both the valves can be opened when there is a single cam. In the case of two cams, one can be used for intake and the second cam is for exhaust.
Valve timing ideal value point changes with a change in rpm. It is related to engine performance and fuel efficiency.
It involves three cams with different timing and lifts profile.
Stage one- low speed.
Stage two- medium speed.
Stage three- high speed.
Example − Honda VTEC system.
Continuously variable valve timing:
Continuously variable valve timing camshaft is fitted with a phaser. It is mounted in place of timing pulley, sprocket, or gear. The principle of phaser is based on a helical gear set or vanes enclosed in a housing. When the engine is running, it helps in changing time from cam-shaft to crankshaft.
It can be electronically or hydraulic controlled.
Example − Toyota’s VVT-i system.
Want to see more full solutions like this?
Chapter 12 Solutions
Automotive Technology: A Systems Approach (MindTap Course List)
- i need the answer quicklyarrow_forwardFor a translating cam-follower system, the pressure angle should: Select one: O a. be 0° O b. be less than 45° O C. not exceed 30° O d. none of these options apply O e. be greater than 45° agearrow_forwardAnalyze the diagram above. Some of the drives system of the figure above has its own depreciation on its efficiencies as the lifecycle progress. State one of the reasons of why the efficiency drop on and explain any method that can increase this efficiency especially on the directional control valvearrow_forward
- Name the engine operating conditions thatmost affect ignition timing requirements.arrow_forwardExplain the benefits of dynamic testing of automatic transmission fluidarrow_forwardwhat is the main advantage of variable valve timing? If you could only vary one valve's timing which would you choose intake or exhaust valve ?arrow_forward
- Automotive Technology: A Systems Approach (MindTa...Mechanical EngineeringISBN:9781133612315Author:Jack Erjavec, Rob ThompsonPublisher:Cengage LearningPrecision Machining Technology (MindTap Course Li...Mechanical EngineeringISBN:9781285444543Author:Peter J. Hoffman, Eric S. Hopewell, Brian JanesPublisher:Cengage LearningElectrical Transformers and Rotating MachinesMechanical EngineeringISBN:9781305494817Author:Stephen L. HermanPublisher:Cengage Learning
- Understanding Motor ControlsMechanical EngineeringISBN:9781337798686Author:Stephen L. HermanPublisher:Delmar Cengage Learning