
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)
- Q6: A turbocharged engine with a compression ratio of 8 is being designed using an air standard cycle. The ambient air is assumed to be 300K and 100 kPa. The temperature at the end of the compression in the cylinder is desired to be 1000K, assuming no combustion prior to reaching TDC. At the end of the cylinder expansion the temperature is also desired to be 1000K. If both the turbine and the compressor have mechanical efficiencies of 80%, what will be the pressure ratio of the compressor and what will be the turbine exhaust temperature?arrow_forwardQ5: A 5.6 litre V8 engine with a compression ratio of 9.4:1 operates on an air-standard Otto cycle at 2800 RPM, with a volumetric efficiency of 90 % and a stoichiometric air-fuel ratio using gasoline. The exhaust flow undergoes a temperature drop of 44ºC as it passes through the turbine of the supercharger. Calculate (a) mass flow rate of exhaust gas and (b) power available to drive the turbocharger compressor.arrow_forwarddo handwrittenarrow_forward
- Create a report: An example of two people who do not understand each other due to lack of communication, and mention ways to resolve the issue between them .arrow_forwardI want the kinematic diagram to be draw like this plsarrow_forwardAccording to the principles and steps above, draw the kinematic diagram of following mechanisms. Mark the appropriate scale, calculates the degree of freedom. NO.1 NO.2 NO: 3 NO.: 4arrow_forward
- An office building is planned with a lateral-force-resisting system designed for earthquake resistance in aseismic zone. The seismic capacity of the proposed system, expressed as a force factor, is assumed tofollow a lognormal distribution with a median of 6.5 and a standard deviation of 1.5. The ground motionfrom the largest expected earthquake at the site is estimated to correspond to an equivalent force factor of 5.5.(a) What is the estimated probability that the building will experience damage when subjected to the largest expected earthquake? (b) If the building survives (i.e., experiences no damage) during a previous moderate earthquake with aforce factor of 4.0, what is the updated probability of failure of the building under the largest expectedearthquake?(c) Suppose future occurrences of the largest expected earthquake follow a Poisson process with a mean return period of 500 years. Assuming that damage events from different earthquakes are statisticallyindependent,…arrow_forwardDuring a plant visit, it was noticed that a 12-m-long section of a 10-cm-diameter steam pipe is completely exposed to the ambient air. The temperature measurements indicate that the average temperature of the outer surface of the steam pipe is 75°C when the ambient temperature is 5°C. There are also light winds in the area at 10 km/h. The emissivity of the outer surface of the pipe is 0.8, and the average temperature of the surfaces surrounding the pipe, including the sky, is estimated to be 0°C. Determine the amount of heat lost from the steam during a 10-h-long work day. Steam is supplied by a gas-fired steam generator that has an efficiency of 80 percent, and the plant pays $1.05/therm of natural gas. If the pipe is insulated and 90 percent of the heat loss is saved, determine the amount of money this facility will save a year as a result of insulating the steam pipes. Assume the plant operates every day of the year for 10 h. State your assumptions.arrow_forwardAn old fashioned ice cream kit consists of two concentric cylinders of radii Ra and Rb. The inner cylinder is filled with milk and ice cream ingredients while the space between the two cylinders is filled with an ice-brine mixture. Ice cream begins to form on the inner surface of the inner cylinder. To expedite the process, would you recommend rotating the inner cylinder? Justify your recommendation. icecream/ ice-brine Ra Rbarrow_forward
- Find temperatures STRICTLY USING RITZ APPROXIMATION METHODarrow_forwardSolve this Problem using RITZ APPROXIMATION. STEP BY STEParrow_forwardB/40 The body is constructed of a uniform square plate, a uniform straight rod, a uniform quarter‐circular rod, and a particle (negligible dimensions). If each part has the indicated mass, determine the mass moments of inertia of the body about the x‐, y‐, and z‐axes. Answer Given.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



