Chapter 7 · MCQ Read Mode

Engine Testing, Performance and Batteries

An engine develops a torque of 200 N·m at 3000 rpm. Its brake power is about:

For a four-stroke engine running at N rpm, the number of power strokes per minute per cylinder is:

If IP = 50 kW and BP = 40 kW, the mechanical efficiency is:

The Willans line method of finding friction power is applicable to:

The Morse test is used to determine the friction power of:

In a Morse test on a 4-cylinder engine, BP with all cylinders = 40 kW and BP with cylinder 1 cut out = 29 kW. IP of cylinder 1 is:

The dynamometer that can absorb power and also drive the engine for a motoring test is the:

An air box is used in air-consumption measurement mainly to:

Brake mean effective pressure (BMEP) is related to IMEP by:

An engine has bsfc = 0.25 kg/kWh with fuel of CV = 42 000 kJ/kg. Its brake thermal efficiency is about:

In a petrol engine at full throttle, maximum brake power occurs:

Load in an SI engine is controlled by:

The absorption dynamometer in which a rotor cuts a magnetic field to produce braking torque is the:

At no load, the mechanical efficiency of an engine is:

As engine speed increases, mechanical efficiency generally:

The volumetric efficiency of an SI engine at part load is low mainly because of:

In a CI engine, the indicated thermal efficiency as load decreases:

The volumetric efficiency of a CI engine is:

Maximum torque of an engine occurs at approximately the speed of maximum:

In the heat balance of a petrol engine, the largest share of fuel energy is usually lost to:

Heat carried away by cooling water is calculated from:

The mass of exhaust gas used in a heat balance calculation is:

The instrument used to measure heat carried away by exhaust gases directly is the:

Fuel heat = 100 kW, BP = 30 kW, cooling water = 25 kW, exhaust = 35 kW. The unaccounted loss is:

The brake thermal efficiency of a diesel engine at full load is typically:

Ethanol is a better fuel for SI engines than for CI engines because it has:

A major cold-starting problem with alcohol fuels arises from their:

Biodiesel is produced from vegetable oils mainly by:

The stoichiometric air-fuel ratio of hydrogen is about:

A major problem of hydrogen in IC engines is:

CNG is stored on vehicles at a pressure of about:

LPG leaks are more dangerous than CNG leaks in closed spaces because LPG is:

The main combustible constituents of producer gas are:

Raw biogas mainly contains:

Compared with diesel, biodiesel generally gives:

A petrol engine converted to run on CNG usually suffers:

A flex-fuel vehicle is one that can run on:

The fuel whose combustion in a fuel cell produces only water is:

The ECM stores its calibration look-up tables (maps) in:

The reference voltage supplied by the ECM to most sensors is:

The ECM works in open-loop mode mainly:

The CAN bus was originally developed by:

The two wires of a CAN bus are called:

The termination resistance at each end of a high-speed CAN bus is:

In CAN, a dominant bit represents logic:

When two CAN nodes start transmitting at the same time, the message that wins arbitration is the one with:

The maximum number of data bytes in a classical CAN data frame is:

The maximum bit rate of high-speed classical CAN is:

The standard CAN 2.0A identifier length is:

A low-cost single-wire serial network used for window, mirror and seat modules is:

A stored diagnostic trouble code (DTC) is read by connecting a scan tool to the:

The throttle position sensor is basically a:

The coolant temperature sensor normally uses an NTC thermistor, whose resistance:

An inductive (magnetic) crankshaft position sensor produces:

The missing teeth on a crankshaft reluctor wheel (e.g., 60-2) are used to:

The camshaft position sensor is needed mainly to:

A hot-wire MAF sensor measures:

A zirconia oxygen sensor output of about 0.9 V indicates:

Oxygen sensors are electrically heated mainly because they:

In electronic spark control, when the knock sensor detects knock, the ECM:

The idle air control valve regulates idle speed by:

In an electronic throttle control (drive-by-wire) system, the throttle plate is opened by:

The purge control solenoid valve of the EVAP system allows:

The quantity of fuel delivered by an electronic port injector is controlled mainly by:

The active material of the positive plate of a charged lead-acid battery is:

During discharge of a lead-acid battery, the specific gravity of the electrolyte:

A 12 V lead-acid battery has:

The specific gravity of the electrolyte in a fully charged lead-acid battery is about:

On discharge, both plates of a lead-acid cell are converted into:

Lead-calcium grids are used in maintenance-free batteries because they:

The ampere-hour capacity of an automobile battery is usually specified at the:

Cold cranking amperes (CCA) is the current a battery can deliver at −18 °C for:

The capacity of a lead-acid battery decreases when:

The watt-hour efficiency of a lead-acid battery is lower than its ampere-hour efficiency because:

A battery left in a discharged condition for a long period mainly suffers from:

The electrolyte level of a conventional battery should be topped up with:

In a high-rate discharge test on a 12 V battery, the voltage should not fall below about:

When removing a battery from a vehicle, the terminal disconnected first is the: